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2022 Volume 37 Issue 12
2022, 37(12): 210604
doi: 10.3866/PKU.DXHX202106046
Abstract:
This paper described the application of electronic density distribution analysis in organic chemistry teaching. In detail, after students got hold of mechanisms of organic reactions, teacher guided students to explore organic reactions based on electronic density distribution analysis of the functional group, to achieve the fusion of isolated, numerous, and weak logical reactions with rules. A knowledge system was therefore formed on the basis of electronic density distribution analysis. For example, integration of the electrophilic/nucleophilic addition reactions of alkenes and nucleophilic addition reactions of aldehydes/ketones has been reached; integration of the electrophilic/nucleophilic substitution reactions on benzene ring/six-membered heteroaromatic ring and electrophilic substitution reactions on five-membered heteroaromatic ring has been reached. Teaching method based on the electronic density distribution analysis helps students to develop organic chemistry thinking. Students therefore found a general method to master organic reactions, significantly reducing students’ burden of memory. In a word, electronic density distribution analysis shows a distinct advantage in improving the efficiency and interest of learning as well as the flexibility in knowledge applications.
This paper described the application of electronic density distribution analysis in organic chemistry teaching. In detail, after students got hold of mechanisms of organic reactions, teacher guided students to explore organic reactions based on electronic density distribution analysis of the functional group, to achieve the fusion of isolated, numerous, and weak logical reactions with rules. A knowledge system was therefore formed on the basis of electronic density distribution analysis. For example, integration of the electrophilic/nucleophilic addition reactions of alkenes and nucleophilic addition reactions of aldehydes/ketones has been reached; integration of the electrophilic/nucleophilic substitution reactions on benzene ring/six-membered heteroaromatic ring and electrophilic substitution reactions on five-membered heteroaromatic ring has been reached. Teaching method based on the electronic density distribution analysis helps students to develop organic chemistry thinking. Students therefore found a general method to master organic reactions, significantly reducing students’ burden of memory. In a word, electronic density distribution analysis shows a distinct advantage in improving the efficiency and interest of learning as well as the flexibility in knowledge applications.
2022, 37(12): 211101
doi: 10.3866/PKU.DXHX202111012
Abstract:
The selectivity is one basic parameter for evaluating analytical method. The International Union of Pure and Applied Chemistry (IUPAC) clearly recommends that the selectivity refers to the extent to which the method can be used to determine particular analytes in mixtures or matrices without interferences from other components of similar behavior. However, its definition and quantitation have still remained open questions. Here, the selectivity on the intrinsic characteristics (definitions), the types of interferences, and the estimation of sensitivity are discussed. Some strategies to improve the selectivity are summarized.
The selectivity is one basic parameter for evaluating analytical method. The International Union of Pure and Applied Chemistry (IUPAC) clearly recommends that the selectivity refers to the extent to which the method can be used to determine particular analytes in mixtures or matrices without interferences from other components of similar behavior. However, its definition and quantitation have still remained open questions. Here, the selectivity on the intrinsic characteristics (definitions), the types of interferences, and the estimation of sensitivity are discussed. Some strategies to improve the selectivity are summarized.
2022, 37(12): 211203
doi: 10.3866/PKU.DXHX202112038
Abstract:
The conception of point group of molecules is one of the core contents in chapter of molecular symmetry of structural chemistry course. It is also one of the basic theories to understand the strucutral symmetry of molecules and the relationship between their structures and molecular properties. Therefore, it is of importance to master the identification method of point group of molecules based on their symmetric elements in structures. This paper compared the identification processes of point group of molecules in different structural chemistry textbooks, discussed potential imperfections of classic identification process of point group of molecules, and proposed a modified identification process of point group of molecules, which could help undergradute and graduate students to know and understand the intention of point group of molecules.
The conception of point group of molecules is one of the core contents in chapter of molecular symmetry of structural chemistry course. It is also one of the basic theories to understand the strucutral symmetry of molecules and the relationship between their structures and molecular properties. Therefore, it is of importance to master the identification method of point group of molecules based on their symmetric elements in structures. This paper compared the identification processes of point group of molecules in different structural chemistry textbooks, discussed potential imperfections of classic identification process of point group of molecules, and proposed a modified identification process of point group of molecules, which could help undergradute and graduate students to know and understand the intention of point group of molecules.
2022, 37(12): 211208
doi: 10.3866/PKU.DXHX202112089
Abstract:
The electrocyclization reaction of chain conjugated polyenes is an important teaching content in the basic chemistry course of undergraduates. Taking the simplest 4n and (4n+2) chain conjugated polyenes as examples, this paper designs a teaching case based on quantum chemical calculations to quantitatively and intuitively describe the stereoselectivity of electrocyclization reactions of chain conjugated polyenes, in order to enable students to deepen their understanding of the electrocyclization reaction mechanism, frontier orbital theory, and molecular orbital symmetry conservation principle.
The electrocyclization reaction of chain conjugated polyenes is an important teaching content in the basic chemistry course of undergraduates. Taking the simplest 4n and (4n+2) chain conjugated polyenes as examples, this paper designs a teaching case based on quantum chemical calculations to quantitatively and intuitively describe the stereoselectivity of electrocyclization reactions of chain conjugated polyenes, in order to enable students to deepen their understanding of the electrocyclization reaction mechanism, frontier orbital theory, and molecular orbital symmetry conservation principle.
2022, 37(12): 220206
doi: 10.3866/PKU.DXHX202202068
Abstract:
In this work, in view of the disadvantages of the previous assessment system based on summative evaluation of basic chemical experiments, an evaluation scale is proposed to evaluate the students’ operation process in combination with an online platform. A comparative practice study of a traditional teaching class and an experimental teaching class reveals that the students’ learning ability is improved and that the operation error rate is reduced according to the students’ feedback results on the evaluation scale. Thus, the learning effect of students is significantly improved. Therefore, the use of the evaluation scale to evaluate operations in experimental course helps formulate the teaching objectives, which is conducive to the training of students and improvement of their experimental skills.
In this work, in view of the disadvantages of the previous assessment system based on summative evaluation of basic chemical experiments, an evaluation scale is proposed to evaluate the students’ operation process in combination with an online platform. A comparative practice study of a traditional teaching class and an experimental teaching class reveals that the students’ learning ability is improved and that the operation error rate is reduced according to the students’ feedback results on the evaluation scale. Thus, the learning effect of students is significantly improved. Therefore, the use of the evaluation scale to evaluate operations in experimental course helps formulate the teaching objectives, which is conducive to the training of students and improvement of their experimental skills.
2022, 37(12): 210704
doi: 10.3866/PKU.DXHX202107046
Abstract:
“The Guidelines for Construction of Ideological and Political Courses in Colleges and Universities” promulgated by Ministry of Education requires the specialized course and the ideological and political course go hand in hand, and constructs a long-term mechanism of moral education. As far as the experiment-based chemistry discipline is concerned, it is also urgent to change the experimental teaching ideas, and strive to cultivate all-round talents with high theoretical level and strong scientific research literacy to meet the needs of the new era. In this paper, the comprehensive chemical experiment based on “BiVO4 nanofiber preparation and electrochemical performance characterization” was selected as a carrier. A new type of comprehensive experimental teaching mode of bidirectional transmission of knowledge between teachers and students was constructed by the integration of the ideological and political elements. The way of scientific research infiltration extends the content of comprehensive chemical experiment to the frontier of scientific researching fields, increases the breadth and novelty of lab teaching content, stimulates students’ enthusiasm for scientific research, enhances students’ passion for basic research, and consolidates the foundation of building a powerful country strong in science and technology. The analysis of typical examples of dissecting sparrows refine the moral elements contained in comprehensive chemical experiments, realize the seamless connection between professional teaching and moral education, further cultivate students’ speculative spirit of exploration and innovation, as well as increase their sense of social responsibility and realize all-round education.
“The Guidelines for Construction of Ideological and Political Courses in Colleges and Universities” promulgated by Ministry of Education requires the specialized course and the ideological and political course go hand in hand, and constructs a long-term mechanism of moral education. As far as the experiment-based chemistry discipline is concerned, it is also urgent to change the experimental teaching ideas, and strive to cultivate all-round talents with high theoretical level and strong scientific research literacy to meet the needs of the new era. In this paper, the comprehensive chemical experiment based on “BiVO4 nanofiber preparation and electrochemical performance characterization” was selected as a carrier. A new type of comprehensive experimental teaching mode of bidirectional transmission of knowledge between teachers and students was constructed by the integration of the ideological and political elements. The way of scientific research infiltration extends the content of comprehensive chemical experiment to the frontier of scientific researching fields, increases the breadth and novelty of lab teaching content, stimulates students’ enthusiasm for scientific research, enhances students’ passion for basic research, and consolidates the foundation of building a powerful country strong in science and technology. The analysis of typical examples of dissecting sparrows refine the moral elements contained in comprehensive chemical experiments, realize the seamless connection between professional teaching and moral education, further cultivate students’ speculative spirit of exploration and innovation, as well as increase their sense of social responsibility and realize all-round education.
2022, 37(12): 211103
doi: 10.3866/PKU.DXHX202111036
Abstract:
Synthesis and characterization of (2R,3R)-1,4-dimethoxyl-1,1,4,4-tetraphenyl-2,3-butanediol is an innovative experiment from the “comprehensive chemistry experiment” course. While (2R,3R)-1,1,4,4-tetraphenylbutanetetraol has found diverse applications in asymmetric organic synthesis, its preparation cost is high, and the synthesis operation is cumbersome and dangerous. (2R,3R)-1,4-dimethoxyl-1,1,4,4-tetraphenyl-2,3-butanediol was synthesized via a highly regioselective reaction of (2R,3R)-1,1,4,4-tetraphenyl-butanetetraol. We propose a comprehensive chemistry experiment that includes classical reaction types, synthetic operations, and characterization analysis. This experiment will strengthen students’ understanding of the theoretical knowledge of organic chemistry and cultivate and improve students’ comprehensive experimental ability. In addition, this experiment also can establish the green chemistry concept among students and stimulate students’ scientific research interest and their awareness of scientific research innovations. Therefore, this experiment is suitable for use as a college chemistry experiment.
Synthesis and characterization of (2R,3R)-1,4-dimethoxyl-1,1,4,4-tetraphenyl-2,3-butanediol is an innovative experiment from the “comprehensive chemistry experiment” course. While (2R,3R)-1,1,4,4-tetraphenylbutanetetraol has found diverse applications in asymmetric organic synthesis, its preparation cost is high, and the synthesis operation is cumbersome and dangerous. (2R,3R)-1,4-dimethoxyl-1,1,4,4-tetraphenyl-2,3-butanediol was synthesized via a highly regioselective reaction of (2R,3R)-1,1,4,4-tetraphenyl-butanetetraol. We propose a comprehensive chemistry experiment that includes classical reaction types, synthetic operations, and characterization analysis. This experiment will strengthen students’ understanding of the theoretical knowledge of organic chemistry and cultivate and improve students’ comprehensive experimental ability. In addition, this experiment also can establish the green chemistry concept among students and stimulate students’ scientific research interest and their awareness of scientific research innovations. Therefore, this experiment is suitable for use as a college chemistry experiment.
2022, 37(12): 211106
doi: 10.3866/PKU.DXHX202111060
Abstract:
We select advanced scientific research results that are suitable for undergraduate laboratory teaching. In order to present a complete process of scientific researches for students, the preparation and characterization of inorganic materials, as well as the establishment and application of optical analysis methods are integrated in this experiment. On the basis of titanium carbide mediated in situ reduction, a label-free, visualized plasmonic sensing method was constructed to achieve highly sensitive and selective detection of silver ions. The implementation of this experiment will not only help students grasp the research paradigm of nanoanalytical chemistry and develop a habit of innovative scientific thinking, but also stimulate students’ interests in studying and enthusiasm to science for serving our country.
We select advanced scientific research results that are suitable for undergraduate laboratory teaching. In order to present a complete process of scientific researches for students, the preparation and characterization of inorganic materials, as well as the establishment and application of optical analysis methods are integrated in this experiment. On the basis of titanium carbide mediated in situ reduction, a label-free, visualized plasmonic sensing method was constructed to achieve highly sensitive and selective detection of silver ions. The implementation of this experiment will not only help students grasp the research paradigm of nanoanalytical chemistry and develop a habit of innovative scientific thinking, but also stimulate students’ interests in studying and enthusiasm to science for serving our country.
2022, 37(12): 211106
doi: 10.3866/PKU.DXHX202111067
Abstract:
Zinc oxide is a usual additive in food, cosmetics, and pharmaceuticals. In this experiment, ZnO content in prickly heat powder and skin ointment was determined by complexometric titration using ethylenediaminetetraacetic acid (EDTA) as the titrant. With real-life pharmaceuticals as experimental materials, it could stimulate the students’ interests in learning the applications of complexometric titrations in quality control. By comparing the experimental results with label information, the students could better understand and master the principle of complexometric titration, experimental operation and analysis of experimental results.
Zinc oxide is a usual additive in food, cosmetics, and pharmaceuticals. In this experiment, ZnO content in prickly heat powder and skin ointment was determined by complexometric titration using ethylenediaminetetraacetic acid (EDTA) as the titrant. With real-life pharmaceuticals as experimental materials, it could stimulate the students’ interests in learning the applications of complexometric titrations in quality control. By comparing the experimental results with label information, the students could better understand and master the principle of complexometric titration, experimental operation and analysis of experimental results.
2022, 37(12): 211106
doi: 10.3866/PKU.DXHX202111069
Abstract:
The 13th five-year plan of education informatization’s requirements and the Ministry of Education’s “experimental plan for training top students in basic disciplines” note the need to fully integrate the information on internet technology and basic chemistry laboratory teaching. They also note the importance of building a virtual simulation laboratory platform that is based on basic theoretical knowledge such as chiral catalysis and drug synthesis, both of which we are committed to. Traditional basic chemistry laboratory limitations with regard to the teaching time, space and safety should be overcome. In addition, teaching methods and connotation of the chemistry laboratory should be enriched to enhance students’ autonomy, practicality, and innovativeness in terms of participating in basic chemistry in the laboratory. Further, innovation in personnel training mechanisms in basic chemistry subjects should be promoted, and the fundamental task of establishing morality and cultivating talents in higher education in the new era should be seen to. In this regard, the problems and difficulties experienced in relation to virtual laboratory teaching were analyzed, and the role of the virtual simulation platform in chemistry laboratory teaching was discussed.
The 13th five-year plan of education informatization’s requirements and the Ministry of Education’s “experimental plan for training top students in basic disciplines” note the need to fully integrate the information on internet technology and basic chemistry laboratory teaching. They also note the importance of building a virtual simulation laboratory platform that is based on basic theoretical knowledge such as chiral catalysis and drug synthesis, both of which we are committed to. Traditional basic chemistry laboratory limitations with regard to the teaching time, space and safety should be overcome. In addition, teaching methods and connotation of the chemistry laboratory should be enriched to enhance students’ autonomy, practicality, and innovativeness in terms of participating in basic chemistry in the laboratory. Further, innovation in personnel training mechanisms in basic chemistry subjects should be promoted, and the fundamental task of establishing morality and cultivating talents in higher education in the new era should be seen to. In this regard, the problems and difficulties experienced in relation to virtual laboratory teaching were analyzed, and the role of the virtual simulation platform in chemistry laboratory teaching was discussed.
2022, 37(12): 211107
doi: 10.3866/PKU.DXHX202111076
Abstract:
The paper, according to the online measuring of aspirin synthesis process, employs the chemometrics method based on the subspace-angle transformations to realize the nondestructive quantification and the trend tracking of aspirin synthesis products. The quantitative relation is the angle value of Raman spectra between the reaction system and the pure aspirin. On the concept introducing for the process analysis technology (PAT) and teachers’ research improvements into the laboratory class, the reform on laboratory teaching is implemented, which enables students to have a direct understanding of new technology. The benefits to students include the broadening of vision, and the improvement of the learn-interest, and the quality and ability of enhancing the innovation.
The paper, according to the online measuring of aspirin synthesis process, employs the chemometrics method based on the subspace-angle transformations to realize the nondestructive quantification and the trend tracking of aspirin synthesis products. The quantitative relation is the angle value of Raman spectra between the reaction system and the pure aspirin. On the concept introducing for the process analysis technology (PAT) and teachers’ research improvements into the laboratory class, the reform on laboratory teaching is implemented, which enables students to have a direct understanding of new technology. The benefits to students include the broadening of vision, and the improvement of the learn-interest, and the quality and ability of enhancing the innovation.
2022, 37(12): 211108
doi: 10.3866/PKU.DXHX202111080
Abstract:
Being complementary to the organic chemistry theory course, organic chemistry laboratory is an important professional basic course. It occupies a very important position in the curriculum of colleges and universities, because it plays an important role in cultivating students’ scientific attitude of linking theory with practice, seeking truth from facts and being strict and serious. The main content has become the entry-level skills for those engaged in chemistry-related professional scientific research. Therefore, it is imperative to carry out the comprehensive innovation experiment of organic chemistry in connection with the frontier of science. The experimental design integrates the synthesis, separation and purification, structural characterization and application of spiropyran molecules with photoisomerization characteristics. The comprehensive experiment is used as the carrier to penetrate the scientific research contents and operation skills into laboratory teaching, so as to preliminarily cultivate students’ interest and ability in scientific research. This experiment not only covers the important theoretical knowledge of organic chemistry and basic laboratory skills, but also focuses on cultivating students’ professional scientific research ability of using modern instruments to analyze the structure of products. Through the application of products in anti-counterfeiting ink, it strengthens students’ awareness of actively mining organic molecules in life. More importantly, this experimental design has great flexibility in teaching arrangement, which can be used in holistic teaching or modular teaching. These characteristics make it more suitable for undergraduate teaching as a comprehensive innovation experiment of scientific research infiltration organic chemistry.
Being complementary to the organic chemistry theory course, organic chemistry laboratory is an important professional basic course. It occupies a very important position in the curriculum of colleges and universities, because it plays an important role in cultivating students’ scientific attitude of linking theory with practice, seeking truth from facts and being strict and serious. The main content has become the entry-level skills for those engaged in chemistry-related professional scientific research. Therefore, it is imperative to carry out the comprehensive innovation experiment of organic chemistry in connection with the frontier of science. The experimental design integrates the synthesis, separation and purification, structural characterization and application of spiropyran molecules with photoisomerization characteristics. The comprehensive experiment is used as the carrier to penetrate the scientific research contents and operation skills into laboratory teaching, so as to preliminarily cultivate students’ interest and ability in scientific research. This experiment not only covers the important theoretical knowledge of organic chemistry and basic laboratory skills, but also focuses on cultivating students’ professional scientific research ability of using modern instruments to analyze the structure of products. Through the application of products in anti-counterfeiting ink, it strengthens students’ awareness of actively mining organic molecules in life. More importantly, this experimental design has great flexibility in teaching arrangement, which can be used in holistic teaching or modular teaching. These characteristics make it more suitable for undergraduate teaching as a comprehensive innovation experiment of scientific research infiltration organic chemistry.
2022, 37(12): 211108
doi: 10.3866/PKU.DXHX202111083
Abstract:
The chemistry practical competition is an advanced form of practical teaching. It can make up for the problems of traditional laboratory teaching items such as obsolete content, backward technical methods, inadequate training, and insufficient innovation. The multi-level, multi-channel, and all-round chemistry laboratory skills competition system provides a rich training platform on which more and more students can be trained. The organic integration of chemistry laboratory skills competition activities and traditional laboratory teaching can promote teaching and learning, enhance training of laboratory skills, improve the quality of practical teaching, better cultivate students’ practical ability, craftsmanship and social responsibility. The implement of cooperative measures transforms selective education into quality education and innovative education. As a result, a new model of chemical practice teaching with characteristics will be formed.
The chemistry practical competition is an advanced form of practical teaching. It can make up for the problems of traditional laboratory teaching items such as obsolete content, backward technical methods, inadequate training, and insufficient innovation. The multi-level, multi-channel, and all-round chemistry laboratory skills competition system provides a rich training platform on which more and more students can be trained. The organic integration of chemistry laboratory skills competition activities and traditional laboratory teaching can promote teaching and learning, enhance training of laboratory skills, improve the quality of practical teaching, better cultivate students’ practical ability, craftsmanship and social responsibility. The implement of cooperative measures transforms selective education into quality education and innovative education. As a result, a new model of chemical practice teaching with characteristics will be formed.
2022, 37(12): 211108
doi: 10.3866/PKU.DXHX202111085
Abstract:
In this study, we introduce an in situ, non-destructive method of chemical element identification utilizing a portable X-ray fluorescence spectrometer (pXRF) to identify the dominant elements of heavy metals in two volumes of Buddhist scriptures from Tang Dynasty collected by Nanjing University Museum. By detecting the ratio of mercury to iron in the scripture marks, and studying the color, we authenticated that the light words on one volume referred to the “blood scripture” were scripted in a mixture of blood and cinnabar. To validate the selection of pXRF rather than the energy dispersive X-ray spectroscopy (EDX) as the chosen detection method, we first analyzed the mercury and iron contents of ancient red pigment cinnabar powder (containing mercury), iron trioxide powder (containing iron), 50 : 50 and 99 : 1 mixtures of the two, and dried animal blood in the laboratory. The results confirmed that pXRF performed well in differentiating the relative contents of mercury and iron, even the trace levels of iron present in the blood sample. Following this check, we used pXRF to detect the dominant elements in the scripture marks of both volumes of Buddhist scriptures at the University Museum. The results indicated that the dark words on one volume referred to the “cinnabar scripture” were written in cinnabar; the light words on the most marks of the blood scripture were written in a mixture of blood and cinnabar, while the dark words on the few marks of the blood scripture were repaired by cinnabar. This study serves as a good example of the interdisciplinary application of college chemistry, providing a reliable, in situ, non-destructive method for element identification in blood scriptures that can be considered cultural relics.
In this study, we introduce an in situ, non-destructive method of chemical element identification utilizing a portable X-ray fluorescence spectrometer (pXRF) to identify the dominant elements of heavy metals in two volumes of Buddhist scriptures from Tang Dynasty collected by Nanjing University Museum. By detecting the ratio of mercury to iron in the scripture marks, and studying the color, we authenticated that the light words on one volume referred to the “blood scripture” were scripted in a mixture of blood and cinnabar. To validate the selection of pXRF rather than the energy dispersive X-ray spectroscopy (EDX) as the chosen detection method, we first analyzed the mercury and iron contents of ancient red pigment cinnabar powder (containing mercury), iron trioxide powder (containing iron), 50 : 50 and 99 : 1 mixtures of the two, and dried animal blood in the laboratory. The results confirmed that pXRF performed well in differentiating the relative contents of mercury and iron, even the trace levels of iron present in the blood sample. Following this check, we used pXRF to detect the dominant elements in the scripture marks of both volumes of Buddhist scriptures at the University Museum. The results indicated that the dark words on one volume referred to the “cinnabar scripture” were written in cinnabar; the light words on the most marks of the blood scripture were written in a mixture of blood and cinnabar, while the dark words on the few marks of the blood scripture were repaired by cinnabar. This study serves as a good example of the interdisciplinary application of college chemistry, providing a reliable, in situ, non-destructive method for element identification in blood scriptures that can be considered cultural relics.
2022, 37(12): 211200
doi: 10.3866/PKU.DXHX202112001
Abstract:
A comprehensive applied chemistry experiment is introduced in this paper, including the synthesis, characterization, and performance of ammonium polyphosphate (APP). This experiment consists of the preparation of APP by low-temperature solvent method, the characterization of APP through Fourier-transform infrared spectroscopy and X-ray diffraction analysis, and the examination of solubility, flame retardancy as well as oxygen index. This experiment can improve students’ ability to broaden the basic chemical knowledge and cultivate the critical thinking, which would greatly assist the training of students’ solid and comprehensive skills, thus, improving the teaching quality of the applied chemistry major.
A comprehensive applied chemistry experiment is introduced in this paper, including the synthesis, characterization, and performance of ammonium polyphosphate (APP). This experiment consists of the preparation of APP by low-temperature solvent method, the characterization of APP through Fourier-transform infrared spectroscopy and X-ray diffraction analysis, and the examination of solubility, flame retardancy as well as oxygen index. This experiment can improve students’ ability to broaden the basic chemical knowledge and cultivate the critical thinking, which would greatly assist the training of students’ solid and comprehensive skills, thus, improving the teaching quality of the applied chemistry major.
2022, 37(12): 211202
doi: 10.3866/PKU.DXHX202112020
Abstract:
The Suzuki-Miyaura cross-coupling reaction is a powerful tool for organic transformations and has been widely used in the synthesis of drugs, natural products, dyes, etc. However, this reaction has not been promoted in undergraduate laboratories due to the expense of the catalyst and the complexity of the reaction. Herein, we present a green organic synthesis experiment utilizing recyclable, commercially available tetraamminepalladium chloride as a catalyst in the Suzuki-Miyaura cross-coupling reaction, significantly reducing experimental costs. Furthermore, this experiment has the advantages of mild reaction conditions, a fast reaction rate, convenient product separation, and the use of water as a solvent, demonstrating the safety benefits of green chemistry and rendering it suitable for integration into an upper-division undergraduate course. While engaging with a Nobel Prize-winning organic synthesis reaction, students will gain an appreciation for green chemistry and catalyst recycling in traditional metal-catalyzed organic reactions, and the advantages in terms of energy savings, emission reduction, and sustainable development.
The Suzuki-Miyaura cross-coupling reaction is a powerful tool for organic transformations and has been widely used in the synthesis of drugs, natural products, dyes, etc. However, this reaction has not been promoted in undergraduate laboratories due to the expense of the catalyst and the complexity of the reaction. Herein, we present a green organic synthesis experiment utilizing recyclable, commercially available tetraamminepalladium chloride as a catalyst in the Suzuki-Miyaura cross-coupling reaction, significantly reducing experimental costs. Furthermore, this experiment has the advantages of mild reaction conditions, a fast reaction rate, convenient product separation, and the use of water as a solvent, demonstrating the safety benefits of green chemistry and rendering it suitable for integration into an upper-division undergraduate course. While engaging with a Nobel Prize-winning organic synthesis reaction, students will gain an appreciation for green chemistry and catalyst recycling in traditional metal-catalyzed organic reactions, and the advantages in terms of energy savings, emission reduction, and sustainable development.
2022, 37(12): 211203
doi: 10.3866/PKU.DXHX202112034
Abstract:
Surface catalysis is an important branch of physical chemistry. The relationship between the surface structure of the catalyst and its catalytic performance is one of the most challenging issues in the fundamental studies of surface catalysis. However, the research contents are rarely involved in the teaching content of chemistry laboratory. In this experiment, we studied the structure-catalytic performance relation of CuO/Cu2O core-shell nanocrystals with different surface structures by combining reaction kinetics analysis and DFT calculations on their catalytic performance in ethylene oxidation. Through this experiment, students will get a profound insight into the relationship between structures and properties of catalysts in surface catalysis.
Surface catalysis is an important branch of physical chemistry. The relationship between the surface structure of the catalyst and its catalytic performance is one of the most challenging issues in the fundamental studies of surface catalysis. However, the research contents are rarely involved in the teaching content of chemistry laboratory. In this experiment, we studied the structure-catalytic performance relation of CuO/Cu2O core-shell nanocrystals with different surface structures by combining reaction kinetics analysis and DFT calculations on their catalytic performance in ethylene oxidation. Through this experiment, students will get a profound insight into the relationship between structures and properties of catalysts in surface catalysis.
2022, 37(12): 211203
doi: 10.3866/PKU.DXHX202112039
Abstract:
This work aims to provide an approach to determine the dissociation constant (pKa) of Eriochrome Black T by using UV-Visible spectrophotometry. The absorbance of Eriochrome Black T was measured at different pH and the data was fitted by ORIGIN with specific function model. Based on the obtained formula, the three pKa of Eriochrome Black T can be calculated, respectively. This method is highly efficient, accurate, and easy to operate. It can also serve as an expansion for the undergraduates’ chemistry laboratory, which can help cultivate the students’ comprehensive ability of experimental design, data processing, and model derivation.
This work aims to provide an approach to determine the dissociation constant (pKa) of Eriochrome Black T by using UV-Visible spectrophotometry. The absorbance of Eriochrome Black T was measured at different pH and the data was fitted by ORIGIN with specific function model. Based on the obtained formula, the three pKa of Eriochrome Black T can be calculated, respectively. This method is highly efficient, accurate, and easy to operate. It can also serve as an expansion for the undergraduates’ chemistry laboratory, which can help cultivate the students’ comprehensive ability of experimental design, data processing, and model derivation.
2022, 37(12): 211204
doi: 10.3866/PKU.DXHX202112045
Abstract:
Recently, the comprehensive innovation experiments for undergraduates played important roles in enriching the teaching contents, establishing new teaching models, and enhancing students’ innovative ability. However, due to the limited time for undergraduates, and their lack of understanding of the background and content of innovation experiments, how to propose a proper comprehensive innovation experiment is very important, and it is also one of the key steps to realize the teaching and training goals. Based on these considerations, the research on “aggregation-induced emission” (AIE) is proposed as a comprehensive innovation experiment. By comparing the photo-physical properties of AIE active tetraphenylethylene and traditional fluorescent material of 4’,5’-dibromofluorescein, and investigating its potential application in fingerprint imaging, it is anticipated that the content in innovative laboratory teaching can be well enriched. While expanding students’ understanding of the relevant background knowledge, their practical ability in fluorescence spectrometers and some other instruments can also be improved. The implementation of this comprehensive innovation experiment can then cultivate and improve students’ ability to discover and solve problems, and finally provide new exploration ideas for their scientific training and innovative thinking.
Recently, the comprehensive innovation experiments for undergraduates played important roles in enriching the teaching contents, establishing new teaching models, and enhancing students’ innovative ability. However, due to the limited time for undergraduates, and their lack of understanding of the background and content of innovation experiments, how to propose a proper comprehensive innovation experiment is very important, and it is also one of the key steps to realize the teaching and training goals. Based on these considerations, the research on “aggregation-induced emission” (AIE) is proposed as a comprehensive innovation experiment. By comparing the photo-physical properties of AIE active tetraphenylethylene and traditional fluorescent material of 4’,5’-dibromofluorescein, and investigating its potential application in fingerprint imaging, it is anticipated that the content in innovative laboratory teaching can be well enriched. While expanding students’ understanding of the relevant background knowledge, their practical ability in fluorescence spectrometers and some other instruments can also be improved. The implementation of this comprehensive innovation experiment can then cultivate and improve students’ ability to discover and solve problems, and finally provide new exploration ideas for their scientific training and innovative thinking.
2022, 37(12): 211204
doi: 10.3866/PKU.DXHX202112046
Abstract:
Recombinant protein preparation is an important part of many chemical biology experiments, but its effective implementation in a regular undergraduate experiment course is limited by the long period of time required. This work reports innovative improvements on the content and teaching methods in an undergraduate teaching experiment: “Preparation and kinetic characterization of metallo-β-lactamase L1”. The main improvements include: (1) using online virtual simulation experiments on a mobile device to study the whole process of L1 preparation and conduct a kinetics study; and (2) offline classroom operation for compulsory and extended experiments. The online resource contains 10 modules, such as polymerase chain reaction of a target gene, recombinant plasmid transformation, protein induction, etc. High-quality simulation of experimental scenarios and human-machine interactive operations provide students with a highly immersive experience, and the coherent experimental arrangement presents a clear knowledge framework. A new offline extension experiment was added to enable the use of the isothermal titration microcalorimetric method to characterize the kinetic parameters of the L1 enzyme. This blended teaching mode realizes the integration of online and offline teaching, which can not only improve the quality and efficiency of teaching, but also broaden students’ horizons and cultivate their hands-on ability and innovation awareness. Thus far, good feedback has been received from preliminary implementation, which is expected to provide a reference for undergraduate experimental teaching in other institutions.
Recombinant protein preparation is an important part of many chemical biology experiments, but its effective implementation in a regular undergraduate experiment course is limited by the long period of time required. This work reports innovative improvements on the content and teaching methods in an undergraduate teaching experiment: “Preparation and kinetic characterization of metallo-β-lactamase L1”. The main improvements include: (1) using online virtual simulation experiments on a mobile device to study the whole process of L1 preparation and conduct a kinetics study; and (2) offline classroom operation for compulsory and extended experiments. The online resource contains 10 modules, such as polymerase chain reaction of a target gene, recombinant plasmid transformation, protein induction, etc. High-quality simulation of experimental scenarios and human-machine interactive operations provide students with a highly immersive experience, and the coherent experimental arrangement presents a clear knowledge framework. A new offline extension experiment was added to enable the use of the isothermal titration microcalorimetric method to characterize the kinetic parameters of the L1 enzyme. This blended teaching mode realizes the integration of online and offline teaching, which can not only improve the quality and efficiency of teaching, but also broaden students’ horizons and cultivate their hands-on ability and innovation awareness. Thus far, good feedback has been received from preliminary implementation, which is expected to provide a reference for undergraduate experimental teaching in other institutions.
2022, 37(12): 211204
doi: 10.3866/PKU.DXHX202112049
Abstract:
The preparation of n-bromobutane by the reaction of n-butanol, sodium bromide, and sulfuric acid is a basic experiment in organic chemistry. In this paper, a tail-gas-absorption reflux device was designed using these three reactants as raw materials. Any two of them were heated to reflux, and then the third was added instantaneously. The effects of different raw-material addition sequences and reflux times on the yield of n-bromobutane were investigated. This experiment can act as a practical reference for domestic universities endeavoring to set up organic chemistry laboratory courses and can also encourage students to see experimental mistakes as opportunities for innovation.
The preparation of n-bromobutane by the reaction of n-butanol, sodium bromide, and sulfuric acid is a basic experiment in organic chemistry. In this paper, a tail-gas-absorption reflux device was designed using these three reactants as raw materials. Any two of them were heated to reflux, and then the third was added instantaneously. The effects of different raw-material addition sequences and reflux times on the yield of n-bromobutane were investigated. This experiment can act as a practical reference for domestic universities endeavoring to set up organic chemistry laboratory courses and can also encourage students to see experimental mistakes as opportunities for innovation.
2022, 37(12): 211205
doi: 10.3866/PKU.DXHX202112050
Abstract:
An experiment was designed to replace benzene with aniline as the raw material in the preparation of p-aminoacetophenone by Friedel-Crafts acylation. In addition to the safety benefits, this modification challenges the students’ ability to continuously synthesize the target product in multiple steps; encourages the students to think about the application of amino protection during synthesis; promotes the use of scientific methods and thinking.
An experiment was designed to replace benzene with aniline as the raw material in the preparation of p-aminoacetophenone by Friedel-Crafts acylation. In addition to the safety benefits, this modification challenges the students’ ability to continuously synthesize the target product in multiple steps; encourages the students to think about the application of amino protection during synthesis; promotes the use of scientific methods and thinking.
2022, 37(12): 211205
doi: 10.3866/PKU.DXHX202112058
Abstract:
Superparamagnetic magnetic iron oxide nanoparticles (SPIONs) show unique magnetic properties and good biocompatibility and have been used extensively in the biomedical field. Of particular interest is the ability of SPIONs to produce thermal energy in response to an external alternating magnetic field, which has shown potential for the treatment of tumors. This study details the synthesis of monodispersed SPIONs and investigates their size- and magnetic field-dependent inductive heating properties. It will encourage students to learn about the controllable synthesis of SPIONs and to understand the mechanism behind magnetic heat induction. This comprehensive experiment considers a cutting-edge topic with great potential for disease treatment, serving to broaden students’ horizons, inspire their interest in scientific research and cultivate their awareness of scientific innovation.
Superparamagnetic magnetic iron oxide nanoparticles (SPIONs) show unique magnetic properties and good biocompatibility and have been used extensively in the biomedical field. Of particular interest is the ability of SPIONs to produce thermal energy in response to an external alternating magnetic field, which has shown potential for the treatment of tumors. This study details the synthesis of monodispersed SPIONs and investigates their size- and magnetic field-dependent inductive heating properties. It will encourage students to learn about the controllable synthesis of SPIONs and to understand the mechanism behind magnetic heat induction. This comprehensive experiment considers a cutting-edge topic with great potential for disease treatment, serving to broaden students’ horizons, inspire their interest in scientific research and cultivate their awareness of scientific innovation.
2022, 37(12): 211206
doi: 10.3866/PKU.DXHX202112069
Abstract:
The “Separation of three organic component mixtures” experiment is arranged by the organic chemistry teaching group of the College of Chemistry and Chemical Engineering of Central South University. The aim is to develop college students’ skills of separation and purification by testing their understanding of and ability to use the principles of extraction, distillation and recrystallization. This experiment is designed for fifth and eighth-year students pursuing studies in clinical medicine, pharmaceutical sciences, biological sciences and applied chemistry. One experimental component, p-toluidine, poses a risk to students, teachers, and laboratory staff due to its toxicity, and wastewater generated does considerable harm to the environment. Furthermore, p-toluidine requires the preparation of ice to facilitate its low melting point, which is not conducive to energy-saving goals. Hence, this paper presents a modified experiment where p-toluidine is replaced by ethyl p-aminobenzoate, a greener, non-toxic alternative which has a higher melting point. After conducting two test acid/alkali separations in the laboratory, Organic Chemistry Experiment B was launched and received positive feedback.
The “Separation of three organic component mixtures” experiment is arranged by the organic chemistry teaching group of the College of Chemistry and Chemical Engineering of Central South University. The aim is to develop college students’ skills of separation and purification by testing their understanding of and ability to use the principles of extraction, distillation and recrystallization. This experiment is designed for fifth and eighth-year students pursuing studies in clinical medicine, pharmaceutical sciences, biological sciences and applied chemistry. One experimental component, p-toluidine, poses a risk to students, teachers, and laboratory staff due to its toxicity, and wastewater generated does considerable harm to the environment. Furthermore, p-toluidine requires the preparation of ice to facilitate its low melting point, which is not conducive to energy-saving goals. Hence, this paper presents a modified experiment where p-toluidine is replaced by ethyl p-aminobenzoate, a greener, non-toxic alternative which has a higher melting point. After conducting two test acid/alkali separations in the laboratory, Organic Chemistry Experiment B was launched and received positive feedback.
2022, 37(12): 211208
doi: 10.3866/PKU.DXHX202112082
Abstract:
An experiment was designed for determination of metal ions in the leaching solution of thermos cups by inductively coupled plasma atomic emission spectrometry (ICP-AES), which can greatly stimulate the students’ interest. This experiment can not only guide students to apply their knowledge and conduct in-depth research, but also improve their laboratory skill and cultivate the spirit of teamwork. This experiment is suitable for undergraduate laboratory teaching, because the content and process of this experiment are complete, the experimental reagents and process are safe and green, the experimental sample processing is quick and easy, and the experimental time is reasonable.
An experiment was designed for determination of metal ions in the leaching solution of thermos cups by inductively coupled plasma atomic emission spectrometry (ICP-AES), which can greatly stimulate the students’ interest. This experiment can not only guide students to apply their knowledge and conduct in-depth research, but also improve their laboratory skill and cultivate the spirit of teamwork. This experiment is suitable for undergraduate laboratory teaching, because the content and process of this experiment are complete, the experimental reagents and process are safe and green, the experimental sample processing is quick and easy, and the experimental time is reasonable.
2022, 37(12): 220807
doi: 10.3866/PKU.DXHX202208076
Abstract:
The charge transfer is a ubiquitous phenomenon in nature, and the physicochemical properties of the materials change due to the change of electronic configurations during the charge-transfer process. Charge transfer complexes with tunable properties actuated by external stimuli have potential applications in the fields of smart responsive materials and molecular sensing. In this paper, a novel comprehensive experiment is designed based on scientific research achievements: the preparation and properties of smart molecular materials with reversible thermal-induced charge-transfer effect. The experiment includes synthesis of metal-organic complexes, preparation of thin-film materials, instrumental analysis of the materials and research on thermochromic effect of materials, in which the main relevant knowledge points of most chemistry courses could be covered. The experiment is comprehensive and presents frontiers of disciplines. Through this experiment, students can not only consolidate the basic knowledge of relevant chemical theory including mastering the synthesis and characterization of metal-organic complexes and understanding the response mechanism of thermal sensor devices, but also can be attracted by the scientific research, and their scientific literacy can be improved.
The charge transfer is a ubiquitous phenomenon in nature, and the physicochemical properties of the materials change due to the change of electronic configurations during the charge-transfer process. Charge transfer complexes with tunable properties actuated by external stimuli have potential applications in the fields of smart responsive materials and molecular sensing. In this paper, a novel comprehensive experiment is designed based on scientific research achievements: the preparation and properties of smart molecular materials with reversible thermal-induced charge-transfer effect. The experiment includes synthesis of metal-organic complexes, preparation of thin-film materials, instrumental analysis of the materials and research on thermochromic effect of materials, in which the main relevant knowledge points of most chemistry courses could be covered. The experiment is comprehensive and presents frontiers of disciplines. Through this experiment, students can not only consolidate the basic knowledge of relevant chemical theory including mastering the synthesis and characterization of metal-organic complexes and understanding the response mechanism of thermal sensor devices, but also can be attracted by the scientific research, and their scientific literacy can be improved.
2022, 37(12): 211102
doi: 10.3866/PKU.DXHX202111026
Abstract:
Blended teaching for physical chemistry was carried out with the organic integration of independent learning and information-based classroom teaching based on the Chao Xing network teaching platform. While inspecting their basic knowledge, the students’ advanced ability and scientific literacy were also evaluated through quantitative indicators, and their learning effectiveness was evaluated in an all-around and multi-level way. The practice results indicated that the process assessment and evaluation system based on their abilities was more conducive to stimulating students’ autonomous learning abilities, cultivating higher-order thinking and scientific ideologies, and improving the ability of sustainable development. This demonstrated that the method could be used to improve the training quality of application-oriented talents in line with the needs of society and enterprises.
Blended teaching for physical chemistry was carried out with the organic integration of independent learning and information-based classroom teaching based on the Chao Xing network teaching platform. While inspecting their basic knowledge, the students’ advanced ability and scientific literacy were also evaluated through quantitative indicators, and their learning effectiveness was evaluated in an all-around and multi-level way. The practice results indicated that the process assessment and evaluation system based on their abilities was more conducive to stimulating students’ autonomous learning abilities, cultivating higher-order thinking and scientific ideologies, and improving the ability of sustainable development. This demonstrated that the method could be used to improve the training quality of application-oriented talents in line with the needs of society and enterprises.
2022, 37(12): 211204
doi: 10.3866/PKU.DXHX202112042
Abstract:
Combined with the modern classroom-teaching concept of “student-oriented”, this paper tries to integrate mind-mapping into task-driven teaching method on analytical chemistry course. The task is using as a bridge to fully stimulate the initiative and enthusiasm of learning, and the knowledge framework of mind mapping is using as a direction to effectively help students understand and grasp the teaching content. Two advanced teaching ways integrate and promote each other to ensure the steady improvement of analytical chemistry teaching effects.
Combined with the modern classroom-teaching concept of “student-oriented”, this paper tries to integrate mind-mapping into task-driven teaching method on analytical chemistry course. The task is using as a bridge to fully stimulate the initiative and enthusiasm of learning, and the knowledge framework of mind mapping is using as a direction to effectively help students understand and grasp the teaching content. Two advanced teaching ways integrate and promote each other to ensure the steady improvement of analytical chemistry teaching effects.
2022, 37(12): 211205
doi: 10.3866/PKU.DXHX202112054
Abstract:
Computational chemistry laboratory is a laboratory course that uses molecular simulation as a tool to solve various core chemical problems through the synergy of “experiment, calculation and theory”. In order to improve the teaching quality of computational chemistry laboratory course, the teaching reform of computational chemistry laboratory course are carried out against the backdrop of COVID-19 prevention. Based on the previous teaching papers of our course group and the teaching practice of our school, we have redesigned and integrated teaching resources, recorded micro-videos of laboratory lectures, designed the pre-class, in-class and after-class learning contents, and constructed an online course of computational chemistry laboratory using Chaoxing Learning Platform. The teaching practice has showed that the mixed mode is beneficial to the mode transformation from “teacher-oriented” to “student-oriented”. It also can improve the students’ ability to analyze and solve problems by using the principles and methods of structural chemistry, and cultivate students’ sense of responsibility and mission to explore the unknown, pursue the truth, and climb the heights of science. Our teaching reform practices not only have good teaching effects, but also provide some references for the teaching reform in university.
Computational chemistry laboratory is a laboratory course that uses molecular simulation as a tool to solve various core chemical problems through the synergy of “experiment, calculation and theory”. In order to improve the teaching quality of computational chemistry laboratory course, the teaching reform of computational chemistry laboratory course are carried out against the backdrop of COVID-19 prevention. Based on the previous teaching papers of our course group and the teaching practice of our school, we have redesigned and integrated teaching resources, recorded micro-videos of laboratory lectures, designed the pre-class, in-class and after-class learning contents, and constructed an online course of computational chemistry laboratory using Chaoxing Learning Platform. The teaching practice has showed that the mixed mode is beneficial to the mode transformation from “teacher-oriented” to “student-oriented”. It also can improve the students’ ability to analyze and solve problems by using the principles and methods of structural chemistry, and cultivate students’ sense of responsibility and mission to explore the unknown, pursue the truth, and climb the heights of science. Our teaching reform practices not only have good teaching effects, but also provide some references for the teaching reform in university.
2022, 37(12): 220300
doi: 10.3866/PKU.DXHX202203006
Abstract:
This paper discusses problems encountered in the training of application-oriented analysis and testing talents under the background of emerging engineering education. Specifically, solutions are put forward from the integration of course ideology and politics, the reconstruction of teaching content, the construction of teaching mode, the improvement of teaching method, and integration of production, teaching and research. While imparting professional knowledge, it cultivates students’ innovative consciousness and ability to help students meet the requirements of employers in terms of comprehensive application ability of instruments as soon as possible after graduation.
This paper discusses problems encountered in the training of application-oriented analysis and testing talents under the background of emerging engineering education. Specifically, solutions are put forward from the integration of course ideology and politics, the reconstruction of teaching content, the construction of teaching mode, the improvement of teaching method, and integration of production, teaching and research. While imparting professional knowledge, it cultivates students’ innovative consciousness and ability to help students meet the requirements of employers in terms of comprehensive application ability of instruments as soon as possible after graduation.
2022, 37(12): 220710
doi: 10.3866/PKU.DXHX202207105
Abstract:
Analytical chemistry is a basic compulsory course for chemical engineering, food science, biological and pharmaceutical majors with many students, which is a good carrier for course ideology and politics. In this paper, the overall design of course ideology and politics in analytical chemistry has been carried out. The case materials have been selected from seven aspects, such as the rise of great powers, regional construction, scientific development, etc. The goal of ideological and political construction of the course is “craftsman spirit of excellence and professional ethics of reverence and integrity”. The ways of integrating ideological and political elements into classroom teaching have been explored by combination the cases and course content organically, and two detailed implementation cases have been formed. It provides ideas for improving the quality and efficiency of ideological and political education in colleges and universities in the new era.
Analytical chemistry is a basic compulsory course for chemical engineering, food science, biological and pharmaceutical majors with many students, which is a good carrier for course ideology and politics. In this paper, the overall design of course ideology and politics in analytical chemistry has been carried out. The case materials have been selected from seven aspects, such as the rise of great powers, regional construction, scientific development, etc. The goal of ideological and political construction of the course is “craftsman spirit of excellence and professional ethics of reverence and integrity”. The ways of integrating ideological and political elements into classroom teaching have been explored by combination the cases and course content organically, and two detailed implementation cases have been formed. It provides ideas for improving the quality and efficiency of ideological and political education in colleges and universities in the new era.
2022, 37(12): 211102
doi: 10.3866/PKU.DXHX202111027
Abstract:
Metallicity is one of major difficulties in inorganic chemistry. The metal element has various ability of losing its electrons in various conditions, so we should analyze the metallicity by using some viewpoints and methods of materialist dialectics. The right evaluation criterion of metallicity is chosen according to actual condition on the basis of the particularity of contradiction. Ionization energy (I) is adopted to evaluate the metallicity when the metal element exists in a free-atom state. ΔfHmϴ or ΔfGmϴ is employed to evaluate the metallicity when the elemental metal reacts with the nonmetal in dry condition. The standard electrode potential (φϴ) is taken to evaluate the metallicity when the elemental metal reacts with the oxidant in aqueous solution. Finally, it is essential to understand the relationship between thermodynamics and dynamics. Thermodynamic criteria (I, ΔfHmϴ, ΔfGmϴ, and φϴ) only indicate the ability of losing electrons, and the reaction rate is depended on actual dynamic factors.
Metallicity is one of major difficulties in inorganic chemistry. The metal element has various ability of losing its electrons in various conditions, so we should analyze the metallicity by using some viewpoints and methods of materialist dialectics. The right evaluation criterion of metallicity is chosen according to actual condition on the basis of the particularity of contradiction. Ionization energy (I) is adopted to evaluate the metallicity when the metal element exists in a free-atom state. ΔfHmϴ or ΔfGmϴ is employed to evaluate the metallicity when the elemental metal reacts with the nonmetal in dry condition. The standard electrode potential (φϴ) is taken to evaluate the metallicity when the elemental metal reacts with the oxidant in aqueous solution. Finally, it is essential to understand the relationship between thermodynamics and dynamics. Thermodynamic criteria (I, ΔfHmϴ, ΔfGmϴ, and φϴ) only indicate the ability of losing electrons, and the reaction rate is depended on actual dynamic factors.
2022, 37(12): 220501
doi: 10.3866/PKU.DXHX202205012
Abstract:
To improve the self-learning ability and inquiry-based learning skills of undergraduates, we guided the students to study the concepts and data in the literature, performed first-principles simulations, analyzed and discussed the relevant results of aromatic hydrocarbon molecules. Through this research-oriented teaching, students understood that the chemical shift is influenced by different substituent groups, chemical structures, and the states of matter, and that spin-spin coupling constants indicate chemical structures. In addition, the students gained further understanding of the relationship between the microscopic structure and macroscopic properties. Moreover, research-oriented teaching improves students’ self-learning skills and ability to apply knowledge and solve problems. Furthermore, this activity type improves students’ ability to explore in-depth knowledge and develop critical thinking skills, which are essential for training innovative scientists and engineers.
To improve the self-learning ability and inquiry-based learning skills of undergraduates, we guided the students to study the concepts and data in the literature, performed first-principles simulations, analyzed and discussed the relevant results of aromatic hydrocarbon molecules. Through this research-oriented teaching, students understood that the chemical shift is influenced by different substituent groups, chemical structures, and the states of matter, and that spin-spin coupling constants indicate chemical structures. In addition, the students gained further understanding of the relationship between the microscopic structure and macroscopic properties. Moreover, research-oriented teaching improves students’ self-learning skills and ability to apply knowledge and solve problems. Furthermore, this activity type improves students’ ability to explore in-depth knowledge and develop critical thinking skills, which are essential for training innovative scientists and engineers.
2022, 37(12): 211200
doi: 10.3866/PKU.DXHX202112005
Abstract:
Experiences on the 2ndNational College Student’s Chemical Experiment Innovative Design Contest were summarized in this paper. By taking our project as an example, discussions and introductions about rules and their corresponding implementation of a science popularization experiment were shared. Based on our reflections on this contest, we regard it as a powerful platform for promoting chemistry laboratory teaching reform in universities, and also we furtherly presented suggestions on ways to extend the contest influence, the construction of the ranks of teachers and the talent cultivation.
Experiences on the 2ndNational College Student’s Chemical Experiment Innovative Design Contest were summarized in this paper. By taking our project as an example, discussions and introductions about rules and their corresponding implementation of a science popularization experiment were shared. Based on our reflections on this contest, we regard it as a powerful platform for promoting chemistry laboratory teaching reform in universities, and also we furtherly presented suggestions on ways to extend the contest influence, the construction of the ranks of teachers and the talent cultivation.
2022, 37(12): 220904
doi: 10.3866/PKU.DXHX202209049
Abstract:
The COVID-19 outbreak has made a dramatic impact worldwide; the development of a rapid and simple method for the detection of SARS-COV-2 is thus of great significance. The problem 1 of the 54th International Chemistry Olympiad examines relevant knowledge in analytical chemistry with a focus on gold nanoparticles and their application in SARS-COV-2 nucleic acid detection.
The COVID-19 outbreak has made a dramatic impact worldwide; the development of a rapid and simple method for the detection of SARS-COV-2 is thus of great significance. The problem 1 of the 54th International Chemistry Olympiad examines relevant knowledge in analytical chemistry with a focus on gold nanoparticles and their application in SARS-COV-2 nucleic acid detection.
2022, 37(12): 220905
doi: 10.3866/PKU.DXHX202209050
Abstract:
Organocatalysis has become the third kind of chemical catalysis besides enzyme and metal catalysis. Under the scientific background of nucleophilic phosphine organocatalysis, problem 6 of the 54th International Chemistry Olympiad is made up of a series of questions which are set with respects of the Lu (3+2) cycloaddition reaction including its occurrence, mechanism, asymmetric variant, and use in organic synthesis. By the diverse questionnaire, problem 6 examines contestants in respects of basic organic chemistry knowledge, learning ability, and logic analysis ability. Meanwhile, it also unveils to contestants a new function of nucleophilic phosphines as organocatalysts.
Organocatalysis has become the third kind of chemical catalysis besides enzyme and metal catalysis. Under the scientific background of nucleophilic phosphine organocatalysis, problem 6 of the 54th International Chemistry Olympiad is made up of a series of questions which are set with respects of the Lu (3+2) cycloaddition reaction including its occurrence, mechanism, asymmetric variant, and use in organic synthesis. By the diverse questionnaire, problem 6 examines contestants in respects of basic organic chemistry knowledge, learning ability, and logic analysis ability. Meanwhile, it also unveils to contestants a new function of nucleophilic phosphines as organocatalysts.
2022, 37(12): 220905
doi: 10.3866/PKU.DXHX202209051
Abstract:
Chiral compounds are very important in people’s life and health. Taking the chiral spiro catalyst developed by the team of academician Zhou Qilin of Nankai University as the main content of the 54th International Chemistry Olympiad, problem 8 investigated the synthesis route of chiral spiro ligand SpiroPAP, the preparation of chiral spiro catalyst Ir-SpiroPAP, and the application of chiral spiro catalyst in the synthesis of natural products.
Chiral compounds are very important in people’s life and health. Taking the chiral spiro catalyst developed by the team of academician Zhou Qilin of Nankai University as the main content of the 54th International Chemistry Olympiad, problem 8 investigated the synthesis route of chiral spiro ligand SpiroPAP, the preparation of chiral spiro catalyst Ir-SpiroPAP, and the application of chiral spiro catalyst in the synthesis of natural products.
Total Synthesis of Capitulactone: Analysis of Problem 9 of the 54th International Chemistry Olympiad
2022, 37(12): 220905
doi: 10.3866/PKU.DXHX202209052
Abstract:
The problem 9 of the 54th International Chemistry Olympiad describes the total synthesis of capitulactone which was isolated from a plant called Curculigo capitulate, a Chinese medicinal herb. Isolation and synthesis of Capitulactone were reported by academician Jian-Min Yue of Shanghai Institute of Materia Medica in 2019. This problem comprises of two parts. The first part is the construction of the skeleton of this natural product, and the second part is the introduction of the stereocenter derived from chiral pool D-mannitol. The interesting thing is that the oxidative cleavage of the protected D-mannitol leads to a single chiral product, and the stereocenter remains neatly during all transformations. The fundamental knowledges examined in this problem include a number of classical organic reactions like electrophilic substitution, nucleophilic substitution, oxidation, reduction, cleavage of ester bond, ring-opening of epoxides, and formation of ketals. Furthermore, protection and deprotection of hydroxyl groups are also involved in this problem.
The problem 9 of the 54th International Chemistry Olympiad describes the total synthesis of capitulactone which was isolated from a plant called Curculigo capitulate, a Chinese medicinal herb. Isolation and synthesis of Capitulactone were reported by academician Jian-Min Yue of Shanghai Institute of Materia Medica in 2019. This problem comprises of two parts. The first part is the construction of the skeleton of this natural product, and the second part is the introduction of the stereocenter derived from chiral pool D-mannitol. The interesting thing is that the oxidative cleavage of the protected D-mannitol leads to a single chiral product, and the stereocenter remains neatly during all transformations. The fundamental knowledges examined in this problem include a number of classical organic reactions like electrophilic substitution, nucleophilic substitution, oxidation, reduction, cleavage of ester bond, ring-opening of epoxides, and formation of ketals. Furthermore, protection and deprotection of hydroxyl groups are also involved in this problem.
2022, 37(12): 220905
doi: 10.3866/PKU.DXHX202209053
Abstract:
Carbon dioxide is considered as the “culprit” of the greenhouse effect, and the study on the capture and transformation of carbon dioxide has been being one of the hot topics of scientific research. The problem 3 of the 54th International Chemistry Olympiad focused on this topic: starting from the absorption of CO2 by NaOH solution, then presenting the development of the electrochemical cycle assisted by H2 to realize the regeneration of absorbent and the recovery of CO2 with high-purity, and finally introducing the structure of new porous materials with zeolite-like imidazolate framework and their application in catalytic conversion of CO2. A story was told about solving the problem by the strategy from conventional mothed to frontier research, from ordinary solution systems to new solid materials. The young students are expected to pay attention to the climate change, to have a comprehensive understanding of the fundamental chemical principles in solving environmental problems, and to devote themselves to developing new methods and materials in the field.
Carbon dioxide is considered as the “culprit” of the greenhouse effect, and the study on the capture and transformation of carbon dioxide has been being one of the hot topics of scientific research. The problem 3 of the 54th International Chemistry Olympiad focused on this topic: starting from the absorption of CO2 by NaOH solution, then presenting the development of the electrochemical cycle assisted by H2 to realize the regeneration of absorbent and the recovery of CO2 with high-purity, and finally introducing the structure of new porous materials with zeolite-like imidazolate framework and their application in catalytic conversion of CO2. A story was told about solving the problem by the strategy from conventional mothed to frontier research, from ordinary solution systems to new solid materials. The young students are expected to pay attention to the climate change, to have a comprehensive understanding of the fundamental chemical principles in solving environmental problems, and to devote themselves to developing new methods and materials in the field.
2022, 37(12): 220905
doi: 10.3866/PKU.DXHX202209059
Abstract:
Nitrogen oxides are a main group of gaseous pollutants. Different nitrogen oxides undergo complicated interconversion in the atmosphere. With the oxidation of NO to NO2 that takes place in the atmosphere and on the surface of solid catalyst as the main content, problem 5 of the 54th International Chemistry Olympiad presents the thermodynamic and dynamic features of this reaction, and illustrates the application of physical chemistry and surface catalysis in environmental treatment.
Nitrogen oxides are a main group of gaseous pollutants. Different nitrogen oxides undergo complicated interconversion in the atmosphere. With the oxidation of NO to NO2 that takes place in the atmosphere and on the surface of solid catalyst as the main content, problem 5 of the 54th International Chemistry Olympiad presents the thermodynamic and dynamic features of this reaction, and illustrates the application of physical chemistry and surface catalysis in environmental treatment.
A New Journey for Ancient Sulfur: Analysis of Problem 4 of the 54th International Chemistry Olympiad
2022, 37(12): 220906
doi: 10.3866/PKU.DXHX202209063
Abstract:
Sulfur is an abundant and inexpensive chemical substance. As cathode material for battery, the theoretical specific capacity of sulfur is as high as 1675 mAh∙g−1. Therefore, lithium-sulfur battery is considered to be one of the most promising devices in the field of energy storage in the future. The problem 4 of the 54th International Chemistry Olympiad takes the frontier research of lithium-sulfur batteries as the main line, and guides students to understand the working principle, fascinating application prospect and some scientific challenges for practical applications of lithium-sulfur batteries. The inspection content covers the chemical reactions between lithium and sulfur-containing substance, back titration, chemical equilibrium, electrochemistry, material and charge conservation.
Sulfur is an abundant and inexpensive chemical substance. As cathode material for battery, the theoretical specific capacity of sulfur is as high as 1675 mAh∙g−1. Therefore, lithium-sulfur battery is considered to be one of the most promising devices in the field of energy storage in the future. The problem 4 of the 54th International Chemistry Olympiad takes the frontier research of lithium-sulfur batteries as the main line, and guides students to understand the working principle, fascinating application prospect and some scientific challenges for practical applications of lithium-sulfur batteries. The inspection content covers the chemical reactions between lithium and sulfur-containing substance, back titration, chemical equilibrium, electrochemistry, material and charge conservation.
2022, 37(12): 220907
doi: 10.3866/PKU.DXHX202209077
Abstract:
Chromium has a long history of application during the development of human society. Based on the various oxidation states of chromium and the characteristic colors of the chromium-containing compounds with different oxidation states, the problem 2 of the 54th International Chemistry Olympiad examined the oxidation changes of chromium and corresponding reactions, the relevant crystal phase structure, and its application in the ceramic glaze and catalytic polymerization.
Chromium has a long history of application during the development of human society. Based on the various oxidation states of chromium and the characteristic colors of the chromium-containing compounds with different oxidation states, the problem 2 of the 54th International Chemistry Olympiad examined the oxidation changes of chromium and corresponding reactions, the relevant crystal phase structure, and its application in the ceramic glaze and catalytic polymerization.
2022, 37(12): 220908
doi: 10.3866/PKU.DXHX202209086
Abstract:
Proteins are a class of organic molecules with important biological activities in life; the synthesis and modification of proteins is an important way to explore the mysteries of life. The problem 7 of the 54th International Chemistry Olympiad mainly focuses on the synthesis and modification of proteins, investigated the construction method of amide bond, the connection strategy of peptides and at last the modification method of protein.
Proteins are a class of organic molecules with important biological activities in life; the synthesis and modification of proteins is an important way to explore the mysteries of life. The problem 7 of the 54th International Chemistry Olympiad mainly focuses on the synthesis and modification of proteins, investigated the construction method of amide bond, the connection strategy of peptides and at last the modification method of protein.
2022, 37(12): 221001
doi: 10.3866/PKU.DXHX202210014
Abstract:
Chemical equilibrium contains information on the extent of reaction, which is an important part of physical chemistry. In the context of the solvation of lithium polysulfide in lithium-sulfur batteries, Q4-9 of the 54th International Chemistry Olympiad (IChO) examined students’ understanding and calculation of the apparent equilibrium constant of the reaction in the equilibrium system of multi conformational compounds. This article will discuss how to apply the weighted average of the free energy of the two conformations of lithium polysulfide to calculate the apparent equilibrium constant from the perspective of thermodynamics and statistical physics.
Chemical equilibrium contains information on the extent of reaction, which is an important part of physical chemistry. In the context of the solvation of lithium polysulfide in lithium-sulfur batteries, Q4-9 of the 54th International Chemistry Olympiad (IChO) examined students’ understanding and calculation of the apparent equilibrium constant of the reaction in the equilibrium system of multi conformational compounds. This article will discuss how to apply the weighted average of the free energy of the two conformations of lithium polysulfide to calculate the apparent equilibrium constant from the perspective of thermodynamics and statistical physics.
