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2023 Volume 38 Issue 9
2023, 38(9): 1-5
doi: 10.3866/PKU.DXHX202210049
Abstract:
The coming of the information age opens up rich resources and approaches for education, and at the same time brings opportunities and challenges to teaching and learning. Based on Outcome Based Education (OBE) teaching philosophy, aiming at the teaching spot problems existing in the principles of chemical engineering, this paper constructs a “five-in-one” teaching mode, including case analysis, theoretical teaching, project-driven teaching, ideological and political guidance as well as network assistance by using of the internet and combining the development needs of life and national low-carbon environmental protection, which starts from the requirements of continuous improvement under the background of engineering certification. Moreover, the innovation teaching mode fully reflects the mutual integration of knowledge objectives, ability objectives and quality objectives, and meets the needs of applied personnel training under the background of emerging engineering education.
The coming of the information age opens up rich resources and approaches for education, and at the same time brings opportunities and challenges to teaching and learning. Based on Outcome Based Education (OBE) teaching philosophy, aiming at the teaching spot problems existing in the principles of chemical engineering, this paper constructs a “five-in-one” teaching mode, including case analysis, theoretical teaching, project-driven teaching, ideological and political guidance as well as network assistance by using of the internet and combining the development needs of life and national low-carbon environmental protection, which starts from the requirements of continuous improvement under the background of engineering certification. Moreover, the innovation teaching mode fully reflects the mutual integration of knowledge objectives, ability objectives and quality objectives, and meets the needs of applied personnel training under the background of emerging engineering education.
2023, 38(9): 6-13
doi: 10.3866/PKU.DXHX202210075
Abstract:
Intangible cultural heritage is the “living” presentation of China's cultural soft power, providing the foundation and nutrients for China's brilliant culture. Based on the chemical wisdom contained in China's intangible cultural heritage, this paper aims to integrate chemistry, science and technology, and culture in general chemistry courses, and make the classroom full of knowledge and interest. We aim to further realize the protection and inheritance of intangible cultural heritage through cultural and educational integration, boost the modernization of intangible cultural heritage, innovate in the protection and inheritance, enhance students' scientific, technological and cultural confidence in intangible cultural heritage, and achieve the goal of promoting protection through learning.
Intangible cultural heritage is the “living” presentation of China's cultural soft power, providing the foundation and nutrients for China's brilliant culture. Based on the chemical wisdom contained in China's intangible cultural heritage, this paper aims to integrate chemistry, science and technology, and culture in general chemistry courses, and make the classroom full of knowledge and interest. We aim to further realize the protection and inheritance of intangible cultural heritage through cultural and educational integration, boost the modernization of intangible cultural heritage, innovate in the protection and inheritance, enhance students' scientific, technological and cultural confidence in intangible cultural heritage, and achieve the goal of promoting protection through learning.
2023, 38(9): 14-18
doi: 10.3866/PKU.DXHX202210048
Abstract:
With the development of the internet technologies as well as the influence of force majeure factors, the traditional classroom teaching can no longer meet the needs of modern teaching of analytical chemistry. Micro-lecture is a newly rising and online-based premium digital teaching resource. This paper takes titration jump as the representative subject in analytical chemistry course, and illustrates the construction, contents, and exhibition of the micro-lecture. The application of online micro-lecture in the teaching of analytical chemistry provides a novel idea for traditional classroom teaching.
With the development of the internet technologies as well as the influence of force majeure factors, the traditional classroom teaching can no longer meet the needs of modern teaching of analytical chemistry. Micro-lecture is a newly rising and online-based premium digital teaching resource. This paper takes titration jump as the representative subject in analytical chemistry course, and illustrates the construction, contents, and exhibition of the micro-lecture. The application of online micro-lecture in the teaching of analytical chemistry provides a novel idea for traditional classroom teaching.
2023, 38(9): 19-24
doi: 10.3866/PKU.DXHX202211021
Abstract:
To culture the applicability of innovating talents, a case-based teaching method involving “three-position and three-combination” learning was conducted with the course content and property. The satisfaction degree and gain sense of students were improved by the innovation of teaching methods, such as the construction of multiple teaching environments, incorporation of the course into multidisciplinary fields, and importance of students' training mode on divergent thinking. The objective of “knowledge ability, ability culture, and value creation” was achieved with great efforts, and the cultivation purpose of applicability of innovating talents was promoted.
To culture the applicability of innovating talents, a case-based teaching method involving “three-position and three-combination” learning was conducted with the course content and property. The satisfaction degree and gain sense of students were improved by the innovation of teaching methods, such as the construction of multiple teaching environments, incorporation of the course into multidisciplinary fields, and importance of students' training mode on divergent thinking. The objective of “knowledge ability, ability culture, and value creation” was achieved with great efforts, and the cultivation purpose of applicability of innovating talents was promoted.
2023, 38(9): 25-31
doi: 10.3866/PKU.DXHX202210080
Abstract:
Under the background of emerging engineering education, the cultivation of innovative practical ability has become the focus of talent training in colleges and universities. As the eyes of scientific research, instrumental analysis involves many fields, reflects the overall thinking and methodology of multidisciplines, and plays an important role in cultivating talents' innovation and practice ability. In view of the many pain points highlighted in the teaching of instrumental analysis course, our team adhered to the teaching reform concept of “student-centered, moral cultivation, integration of thinking and innovation and integration of knowledge and practice”, reconstructed the curriculum teaching objectives and three-dimensional evaluation system guided by the cultivation of students' innovative practical ability. The four-round integrated teaching modes including the combination of explicit knowledge and implicit values, online and offline, problem-driven teaching and visual teaching, and theoretical teaching and research practice, is adopted for teaching innovation. It has been proved that the new teaching model has greatly stimulated students' interest in learning and desire for knowledge. Based on this teaching reform effort, the students' curriculum performance has been continuously improved, and their comprehensive innovation practice ability has also been well shaped.
Under the background of emerging engineering education, the cultivation of innovative practical ability has become the focus of talent training in colleges and universities. As the eyes of scientific research, instrumental analysis involves many fields, reflects the overall thinking and methodology of multidisciplines, and plays an important role in cultivating talents' innovation and practice ability. In view of the many pain points highlighted in the teaching of instrumental analysis course, our team adhered to the teaching reform concept of “student-centered, moral cultivation, integration of thinking and innovation and integration of knowledge and practice”, reconstructed the curriculum teaching objectives and three-dimensional evaluation system guided by the cultivation of students' innovative practical ability. The four-round integrated teaching modes including the combination of explicit knowledge and implicit values, online and offline, problem-driven teaching and visual teaching, and theoretical teaching and research practice, is adopted for teaching innovation. It has been proved that the new teaching model has greatly stimulated students' interest in learning and desire for knowledge. Based on this teaching reform effort, the students' curriculum performance has been continuously improved, and their comprehensive innovation practice ability has also been well shaped.
2023, 38(9): 32-38
doi: 10.3866/PKU.DXHX202211096
Abstract:
Based on the online and offline teaching of chemical engineering principles course, we carried out the teaching exploration combined with online preview, flipped classroom and home exploration on the basis of cooperative group learning. This work shows the teaching mode by taking the simple calculation of the tray number of distillation column as an example. On the basis of class grouping and pre-class thinking questions, the teacher guides students to online preview and cooperative group discussion with questions, by which students' learning initiative is ignited, and the teaching effect and efficiency of offline flipped classroom are greatly improved. Through flipped classroom and cooperative group learning, students master the ideas and methods to solve the complex engineering problems in chemical engineering, and can solve the corresponding complex engineering problems. Through extending problems and post-class group cooperation, students are guided to study and explore after class, by which students' scientific research and innovation ability is cultivated. Our teaching experiences indicated that “online preview-flipped classroom-home exploration” on the basis of cooperative group learning can be used as a general teaching mode in higher engineering education with high efficiency.
Based on the online and offline teaching of chemical engineering principles course, we carried out the teaching exploration combined with online preview, flipped classroom and home exploration on the basis of cooperative group learning. This work shows the teaching mode by taking the simple calculation of the tray number of distillation column as an example. On the basis of class grouping and pre-class thinking questions, the teacher guides students to online preview and cooperative group discussion with questions, by which students' learning initiative is ignited, and the teaching effect and efficiency of offline flipped classroom are greatly improved. Through flipped classroom and cooperative group learning, students master the ideas and methods to solve the complex engineering problems in chemical engineering, and can solve the corresponding complex engineering problems. Through extending problems and post-class group cooperation, students are guided to study and explore after class, by which students' scientific research and innovation ability is cultivated. Our teaching experiences indicated that “online preview-flipped classroom-home exploration” on the basis of cooperative group learning can be used as a general teaching mode in higher engineering education with high efficiency.
2023, 38(9): 39-46
doi: 10.3866/PKU.DXHX202210084
Abstract:
An online course of physical chemistry experiment was developed. The primary goal of the course is to bridge the gap between the challenges posed by physical chemistry experiment and limited classroom teaching time. Moreover, we anticipate that the course will compensate for the shortcomings of traditional physical chemistry experiment teaching, which emphasizes the process and ignores the results. This online course should cultivate student knowledge, skills, and thinking ability through modules, such as experimental principles, instrument operation simulation, experimental exercises, and problem solving. Furthermore, the course can serve as a remarkable complementary approach to offline experimental operation training. The online course of physical chemistry experiment provides a prerequisite for flipping the traditional classroom of physical chemistry experiment and significantly improves teaching effects.
An online course of physical chemistry experiment was developed. The primary goal of the course is to bridge the gap between the challenges posed by physical chemistry experiment and limited classroom teaching time. Moreover, we anticipate that the course will compensate for the shortcomings of traditional physical chemistry experiment teaching, which emphasizes the process and ignores the results. This online course should cultivate student knowledge, skills, and thinking ability through modules, such as experimental principles, instrument operation simulation, experimental exercises, and problem solving. Furthermore, the course can serve as a remarkable complementary approach to offline experimental operation training. The online course of physical chemistry experiment provides a prerequisite for flipping the traditional classroom of physical chemistry experiment and significantly improves teaching effects.
2023, 38(9): 47-51
doi: 10.3866/PKU.DXHX202210069
Abstract:
The course of “college chemistry” emphasizes both basic theories and laboratory teaching. Under the background of “emerging engineering education” which pays attention to creativity and innovation, the authors expanded basic chemical knowledge and linked it with undergraduates' science and technology activities, forming the innovation cultivation pattern of “classroom teaching, mini-project, and competition”. The achievements on innovative experiments from research were introduced to the class. Teaching practice shows that it's favorable for inspiring the students, utilizing chemical knowledge in practical applications, and also cultivating students' ability of innovation in scientific research.
The course of “college chemistry” emphasizes both basic theories and laboratory teaching. Under the background of “emerging engineering education” which pays attention to creativity and innovation, the authors expanded basic chemical knowledge and linked it with undergraduates' science and technology activities, forming the innovation cultivation pattern of “classroom teaching, mini-project, and competition”. The achievements on innovative experiments from research were introduced to the class. Teaching practice shows that it's favorable for inspiring the students, utilizing chemical knowledge in practical applications, and also cultivating students' ability of innovation in scientific research.
Exploration and Practice of Efficient Diversified Teaching Mode of Specialized English for Chemistry
2023, 38(9): 52-59
doi: 10.3866/PKU.DXHX202211074
Abstract:
In this paper, an efficient diversified teaching method was proposed to address the issues on teaching of specialized English for chemistry. The method includes summarizing words and terms by suffix and prefix in lectures for improving learning efficiency, classroom interactions based on “flipped classroom” for promoting study interests, daily post-class practice on listening and on online teaching platforms for enhancing listening and oral skills, and seminar-based classroom activity in each section of the courses for improving subjective initiative for learning. This method provides an important reference for teaching reform of specialized English for chemistry.
In this paper, an efficient diversified teaching method was proposed to address the issues on teaching of specialized English for chemistry. The method includes summarizing words and terms by suffix and prefix in lectures for improving learning efficiency, classroom interactions based on “flipped classroom” for promoting study interests, daily post-class practice on listening and on online teaching platforms for enhancing listening and oral skills, and seminar-based classroom activity in each section of the courses for improving subjective initiative for learning. This method provides an important reference for teaching reform of specialized English for chemistry.
2023, 38(9): 60-68
doi: 10.3866/PKU.DXHX202303012
Abstract:
Accurate grasp of students' learning status is the basis of promoting curriculum reform and improving the teaching quality. Through this survey, the basic situation of students' learning of inorganic chemistry laboratory was analyzed, including learning interests, learning objectives, preview methods, preview effects, laboratory skills and learning effects. The main problems and demands of students in the course were summarized, and some improvement measures for effective teaching of inorganic chemistry laboratory were put forward through data analysis.
Accurate grasp of students' learning status is the basis of promoting curriculum reform and improving the teaching quality. Through this survey, the basic situation of students' learning of inorganic chemistry laboratory was analyzed, including learning interests, learning objectives, preview methods, preview effects, laboratory skills and learning effects. The main problems and demands of students in the course were summarized, and some improvement measures for effective teaching of inorganic chemistry laboratory were put forward through data analysis.
2023, 38(9): 69-79
doi: 10.3866/PKU.DXHX202306070
Abstract:
The blended teaching design of inorganic chemistry experiments, utilizing the BOPPPS framework, places a strong emphasis on “learning centered”. This paper presents the application of the BOPPPS model in the teaching of “Determination of Composition and the Stable Constant of the Sulfosalicylic Acid Iron (III) Complex”, outlining its implementation process. Research findings indicate that this approach effectively fosters students' self-learning, enhances teaching efficiency, and cultivates students' experimental and communication skills. Furthermore, it enables the identification of teaching blind spots and difficulties, thereby facilitating ongoing improvements to the teaching methodology.
The blended teaching design of inorganic chemistry experiments, utilizing the BOPPPS framework, places a strong emphasis on “learning centered”. This paper presents the application of the BOPPPS model in the teaching of “Determination of Composition and the Stable Constant of the Sulfosalicylic Acid Iron (III) Complex”, outlining its implementation process. Research findings indicate that this approach effectively fosters students' self-learning, enhances teaching efficiency, and cultivates students' experimental and communication skills. Furthermore, it enables the identification of teaching blind spots and difficulties, thereby facilitating ongoing improvements to the teaching methodology.
2023, 38(9): 80-88
doi: 10.3866/PKU.DXHX202210082
Abstract:
The method of roasting coffee beans was invented by the Arabs of Yemen, who then spread the method to Egypt and Turkey, and finally worldwide. This paper provides a detailed understanding of coffee beans from a chemical perspective, including discussions on identification of two coffee bean varieties—Arabica and Robusta, the chemical process of coffee roasting, and the pore structure of coffee beans.
The method of roasting coffee beans was invented by the Arabs of Yemen, who then spread the method to Egypt and Turkey, and finally worldwide. This paper provides a detailed understanding of coffee beans from a chemical perspective, including discussions on identification of two coffee bean varieties—Arabica and Robusta, the chemical process of coffee roasting, and the pore structure of coffee beans.
2023, 38(9): 89-97
doi: 10.3866/PKU.DXHX202210081
Abstract:
The microfluidics has been widely applied in analytical chemistry and many other fields ascribed to its excellent ability to manipulate fluids on the microscale. The introduction of microfluidics to the undergraduate courses of analytical chemistry will expand the cutting-edge contents, help the teaching process and improve students' learning interest. Herein, we review the history of microfluidics, summarize the ideological and political elements in these contents, briefly introduce the important theories in the area of microfluidics and fabrication processes of microfluidic chips, and discuss their relationship with analytical chemistry. Recent research progresses of the microfluidics in the fields of analytical chemistry research are presented with a focus on bioanalysis. We hope this can be a reference for the introduction of microfluidics into the teaching of analytical chemistry.
The microfluidics has been widely applied in analytical chemistry and many other fields ascribed to its excellent ability to manipulate fluids on the microscale. The introduction of microfluidics to the undergraduate courses of analytical chemistry will expand the cutting-edge contents, help the teaching process and improve students' learning interest. Herein, we review the history of microfluidics, summarize the ideological and political elements in these contents, briefly introduce the important theories in the area of microfluidics and fabrication processes of microfluidic chips, and discuss their relationship with analytical chemistry. Recent research progresses of the microfluidics in the fields of analytical chemistry research are presented with a focus on bioanalysis. We hope this can be a reference for the introduction of microfluidics into the teaching of analytical chemistry.
2023, 38(9): 98-104
doi: 10.3866/PKU.DXHX202211088
Abstract:
This paper investigates the significance of element speciation analysis, the various hyphenated techniques used in element speciation analysis, and their application in real samples. This involves a variety of separation technologies, such as high-performance liquid chromatography, ion chromatography, size exclusion chromatography, gas chromatography, and capillary electrophoresis, as well as various detection methods, such as inductively coupled plasma mass spectrometry, inductively coupled plasma optical emission spectrometry, atomic fluorescence spectrometry, and atomic absorption spectrometry. Based on this, we developed teaching experiments, combined theory with practice, and further strengthened students' understanding, mastery, and application of knowledge.
This paper investigates the significance of element speciation analysis, the various hyphenated techniques used in element speciation analysis, and their application in real samples. This involves a variety of separation technologies, such as high-performance liquid chromatography, ion chromatography, size exclusion chromatography, gas chromatography, and capillary electrophoresis, as well as various detection methods, such as inductively coupled plasma mass spectrometry, inductively coupled plasma optical emission spectrometry, atomic fluorescence spectrometry, and atomic absorption spectrometry. Based on this, we developed teaching experiments, combined theory with practice, and further strengthened students' understanding, mastery, and application of knowledge.
2023, 38(9): 105-113
doi: 10.3866/PKU.DXHX202212053
Abstract:
The scientific characterization of the properties of mesoporous materials is a key link for their development and application. In this paper, the development history, application scope, and characteristics of mesoporous adsorption and commonly used classical analytical models are briefly introduced by tabular comparison. To systematically understand the classical mesoporous analysis methods in physical adsorption, they were classified into four categories: modeled, model-free, completely model-free, and reverse methods. Then, these methods and three frequently-used analytical software for mesoporous adsorption were compared and analyzed. This has reference value for technicians of adsorption instrument management as well as for teaching and research of mesoporous materials.
The scientific characterization of the properties of mesoporous materials is a key link for their development and application. In this paper, the development history, application scope, and characteristics of mesoporous adsorption and commonly used classical analytical models are briefly introduced by tabular comparison. To systematically understand the classical mesoporous analysis methods in physical adsorption, they were classified into four categories: modeled, model-free, completely model-free, and reverse methods. Then, these methods and three frequently-used analytical software for mesoporous adsorption were compared and analyzed. This has reference value for technicians of adsorption instrument management as well as for teaching and research of mesoporous materials.
2023, 38(9): 114-121
doi: 10.3866/PKU.DXHX202210057
Abstract:
Nanomaterial coatings endow traditional fabrics with incomparable properties, such as anti-fouling and waterproofing, and have thus garnered widespread attention. However, the underlying principle of such properties is not widely known. In this experiment, a superhydrophobic fabric coating was produced by a simple copper reduction reaction. After oxidation treatment, the fabric exhibited superhydrophobicity in oil and superoleophobicity in water. Thus, demonstrating the characteristics of copper superwetting fabrics with typical interactive experiments would be significant in popularizing science.
Nanomaterial coatings endow traditional fabrics with incomparable properties, such as anti-fouling and waterproofing, and have thus garnered widespread attention. However, the underlying principle of such properties is not widely known. In this experiment, a superhydrophobic fabric coating was produced by a simple copper reduction reaction. After oxidation treatment, the fabric exhibited superhydrophobicity in oil and superoleophobicity in water. Thus, demonstrating the characteristics of copper superwetting fabrics with typical interactive experiments would be significant in popularizing science.
2023, 38(9): 122-130
doi: 10.3866/PKU.DXHX202210053
Abstract:
To achieve the goals of scientific research on back-feeding teaching and teaching innovation to promote personnel training, reforming traditional chemical experiments is necessary. Based on previous scientific research achievements of the research team, a comprehensive chemical experiment was designed to synthesize and characterize fluorescent copper nanoclusters using DNA molecules as templates, and the conditions for stable synthesis of fluorescent copper nanoclusters were obtained. The experiment included the synthesis of nanoclusters, use of basic spectral analysis instruments, and spectral data processing. The experiment integrates the frontier knowledge of analytical chemistry, biochemistry, and nanoscience, among others. The experimental conditions were simple and mild, and the experimental duration was reasonable, meeting the requirements of experimental teaching, stimulating students' interest in scientific research, enhancing their comprehensive ability, and promoting experimental teaching.
To achieve the goals of scientific research on back-feeding teaching and teaching innovation to promote personnel training, reforming traditional chemical experiments is necessary. Based on previous scientific research achievements of the research team, a comprehensive chemical experiment was designed to synthesize and characterize fluorescent copper nanoclusters using DNA molecules as templates, and the conditions for stable synthesis of fluorescent copper nanoclusters were obtained. The experiment included the synthesis of nanoclusters, use of basic spectral analysis instruments, and spectral data processing. The experiment integrates the frontier knowledge of analytical chemistry, biochemistry, and nanoscience, among others. The experimental conditions were simple and mild, and the experimental duration was reasonable, meeting the requirements of experimental teaching, stimulating students' interest in scientific research, enhancing their comprehensive ability, and promoting experimental teaching.
2023, 38(9): 131-140
doi: 10.3866/PKU.DXHX202211005
Abstract:
In this paper, a simulation scenario of organic dye in sewage was constructed, along with the theory of photogenerated carriers-driven reaction of photocatalysts. A comprehensive experiment of green chemistry based on TiO2/g-C3N4 for the photocatalytic degradation of organic dye in water was designed. In the experiment, TiO2/g-C3N4 composite was synthesized by calcination, and its intrinsic structure and degradation performance were studied by X-ray diffraction, transmittance electron microscope, X-ray photoelectron spectroscopy, automatic physical adsorption measurements and ultraviolet-visible spectrophotometry. The comprehensive experiment involves material preparation, detailed characterization, pollutant degradation and other experimental sections to realize the cross-integration of inorganic chemistry, physical chemistry and other disciplines, which bears the concept of green chemistry. Moreover, the experiment is combined with the photocatalytic degradation of inorganic nanomaterials, which is the hot spot in current disciplines. Additionally, it promotes the combination between the theories and practice of synthesis, and more talents in scientific innovation with high ideals can be trained in the process of China's modernization drive.
In this paper, a simulation scenario of organic dye in sewage was constructed, along with the theory of photogenerated carriers-driven reaction of photocatalysts. A comprehensive experiment of green chemistry based on TiO2/g-C3N4 for the photocatalytic degradation of organic dye in water was designed. In the experiment, TiO2/g-C3N4 composite was synthesized by calcination, and its intrinsic structure and degradation performance were studied by X-ray diffraction, transmittance electron microscope, X-ray photoelectron spectroscopy, automatic physical adsorption measurements and ultraviolet-visible spectrophotometry. The comprehensive experiment involves material preparation, detailed characterization, pollutant degradation and other experimental sections to realize the cross-integration of inorganic chemistry, physical chemistry and other disciplines, which bears the concept of green chemistry. Moreover, the experiment is combined with the photocatalytic degradation of inorganic nanomaterials, which is the hot spot in current disciplines. Additionally, it promotes the combination between the theories and practice of synthesis, and more talents in scientific innovation with high ideals can be trained in the process of China's modernization drive.
2023, 38(9): 141-147
doi: 10.3866/PKU.DXHX202210005
Abstract:
We introduce a comprehensive chemistry experiment, namely “Nomenclature, synthesis, and characterization of fascaplysin alkaloids”. The experiment involves the nomenclature, preparation, separation, purification, and characterization of fused-ring fascaplysin alkaloids. During the experiment, frontier scientific tools, especially the I2/DMSO combination reagent system, were used to synthesize natural products such as fascaplysin alkaloids starting from aryl ketones to realize green organic chemical synthesis experiments. This approach deepens the understanding of fused ring compounds, stimulates independent thinking and innovation consciousness in students, and could be conducive for cultivating application-oriented talents in emerging engineering.
We introduce a comprehensive chemistry experiment, namely “Nomenclature, synthesis, and characterization of fascaplysin alkaloids”. The experiment involves the nomenclature, preparation, separation, purification, and characterization of fused-ring fascaplysin alkaloids. During the experiment, frontier scientific tools, especially the I2/DMSO combination reagent system, were used to synthesize natural products such as fascaplysin alkaloids starting from aryl ketones to realize green organic chemical synthesis experiments. This approach deepens the understanding of fused ring compounds, stimulates independent thinking and innovation consciousness in students, and could be conducive for cultivating application-oriented talents in emerging engineering.
2023, 38(9): 148-155
doi: 10.3866/PKU.DXHX202210066
Abstract:
The effective conversion of carbon dioxide (CO2) into high value-added carbon-containing chemicals or liquid fuels in mild condition is greatly significant for reducing air pollution and supplementing carbon-containing energy shortages. Polyoxometalates (POMs) possess semiconductor-like properties, reversible redox properties, and structural stability, which represent a class of good electron acceptors that can effectively enhance the photocatalytic performance of semiconductor catalysts. This paper discusses an innovatively designed comprehensive experiment based on scientific research results. The CrMo6/TiO2 photocatalyst was prepared by loading Anderson type POMs, such as CrMo6 on TiO2, by the impregnation method. The material structure was analyzed by means of Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and UV-Vis diffuse reflectance. The research results showed that CrMo6/TiO2 can efficiently convert carbon dioxide into formic acid and other liquid products. Anderson type POMs modification of TiO2 can reduce the energy band gap and the energy required for photocatalysis. This experiment combines inorganic chemistry, physical chemistry, materials chemistry, organic chemistry, analytical chemistry, and other basic chemistry courses, popularizes the concepts of synthetic chemistry and green chemistry, and improves students' environmental awareness, innovation ability, and comprehensive ability.
The effective conversion of carbon dioxide (CO2) into high value-added carbon-containing chemicals or liquid fuels in mild condition is greatly significant for reducing air pollution and supplementing carbon-containing energy shortages. Polyoxometalates (POMs) possess semiconductor-like properties, reversible redox properties, and structural stability, which represent a class of good electron acceptors that can effectively enhance the photocatalytic performance of semiconductor catalysts. This paper discusses an innovatively designed comprehensive experiment based on scientific research results. The CrMo6/TiO2 photocatalyst was prepared by loading Anderson type POMs, such as CrMo6 on TiO2, by the impregnation method. The material structure was analyzed by means of Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and UV-Vis diffuse reflectance. The research results showed that CrMo6/TiO2 can efficiently convert carbon dioxide into formic acid and other liquid products. Anderson type POMs modification of TiO2 can reduce the energy band gap and the energy required for photocatalysis. This experiment combines inorganic chemistry, physical chemistry, materials chemistry, organic chemistry, analytical chemistry, and other basic chemistry courses, popularizes the concepts of synthetic chemistry and green chemistry, and improves students' environmental awareness, innovation ability, and comprehensive ability.
2023, 38(9): 156-162
doi: 10.3866/PKU.DXHX202210011
Abstract:
The preparation of repairable hydrogels is an extensively researched multidisciplinary topic, incorporating organic chemistry, polymer chemistry, material chemistry, and biomimetic materials. Thus, it has tremendous potential for further adaptation in undergraduate teaching experiments. Herein, we propose a novel comprehensive experiment to study the preparation and self-healing performance of self-healing hydrogels based on an agarose/PVA dual network. The experiment is vivid and interesting. Students can shape and design the hydrogels in a variety of ways during the experiment, which can stimulate students' interest and enthusiasm in learning chemistry. As a low-cost and environment-friendly material, hydrogels are also suitable for teaching the concepts of green chemistry, sustainable development, and environmental protection.
The preparation of repairable hydrogels is an extensively researched multidisciplinary topic, incorporating organic chemistry, polymer chemistry, material chemistry, and biomimetic materials. Thus, it has tremendous potential for further adaptation in undergraduate teaching experiments. Herein, we propose a novel comprehensive experiment to study the preparation and self-healing performance of self-healing hydrogels based on an agarose/PVA dual network. The experiment is vivid and interesting. Students can shape and design the hydrogels in a variety of ways during the experiment, which can stimulate students' interest and enthusiasm in learning chemistry. As a low-cost and environment-friendly material, hydrogels are also suitable for teaching the concepts of green chemistry, sustainable development, and environmental protection.
2023, 38(9): 163-171
doi: 10.3866/PKU.DXHX202210012
Abstract:
An exploratory analytical chemistry comprehensive experiment was designed based on Prussian blue analog-derived nanoenzymes. The experiment includes the preparation and characterization of three kinds of Prussian blue analog-derived nanoenzyme materials and the determination of their enzyme catalytic reaction rate constants. These nanomaterials were further applied to hydrogen peroxide detection. As this experiment features inexpensive reagents, mild reaction conditions, obvious experimental phenomena, and reasonable time allocation, it is suitable for undergraduate laboratory teaching to improve students' experimental skills and cultivate their scientific research and innovation ability.
An exploratory analytical chemistry comprehensive experiment was designed based on Prussian blue analog-derived nanoenzymes. The experiment includes the preparation and characterization of three kinds of Prussian blue analog-derived nanoenzyme materials and the determination of their enzyme catalytic reaction rate constants. These nanomaterials were further applied to hydrogen peroxide detection. As this experiment features inexpensive reagents, mild reaction conditions, obvious experimental phenomena, and reasonable time allocation, it is suitable for undergraduate laboratory teaching to improve students' experimental skills and cultivate their scientific research and innovation ability.
2023, 38(9): 172-178
doi: 10.3866/PKU.DXHX202210077
Abstract:
The preparation of triphenylmethanol is a classic teaching experiment in the field of chemistry and serves as an important combination of organic chemistry theory and practical laboratory skills. However, the experiment has a low success rate due to the complexity of the apparatus, difficulties in handling Grignard reagents, and the strict requirements for anhydrous and oxygen-free conditions. Moreover, repeated solvent transfers result in solvent exposure for both teachers and students. In this study, we designed and constructed a continuous flow apparatus for the preparation of Grignard reagents using a medium-pressure syringe pump and a fixed-bed continuous flow reactor, achieving the continuous production of triphenylmethanol. The continuous flow apparatus for Grignard reagent preparation is simple to assemble, completely eliminates organic solvent exposure for teachers and students, and exhibits good reproducibility in the conversion of bromobenzene to Grignard reagent. Within this continuous flow setup, the preparation of Grignard reagents is stable, controllable, and safe. Excess magnesium turnings do not require quenching and can be reused.
The preparation of triphenylmethanol is a classic teaching experiment in the field of chemistry and serves as an important combination of organic chemistry theory and practical laboratory skills. However, the experiment has a low success rate due to the complexity of the apparatus, difficulties in handling Grignard reagents, and the strict requirements for anhydrous and oxygen-free conditions. Moreover, repeated solvent transfers result in solvent exposure for both teachers and students. In this study, we designed and constructed a continuous flow apparatus for the preparation of Grignard reagents using a medium-pressure syringe pump and a fixed-bed continuous flow reactor, achieving the continuous production of triphenylmethanol. The continuous flow apparatus for Grignard reagent preparation is simple to assemble, completely eliminates organic solvent exposure for teachers and students, and exhibits good reproducibility in the conversion of bromobenzene to Grignard reagent. Within this continuous flow setup, the preparation of Grignard reagents is stable, controllable, and safe. Excess magnesium turnings do not require quenching and can be reused.
2023, 38(9): 179-187
doi: 10.3866/PKU.DXHX202210105
Abstract:
We introduce an exploratory computational chemistry experiment for senior undergraduate students. By studying the reaction mechanisms of intra- and intermolecular ethanol dehydration, students can understand the role of acid catalysts in alcohol dehydration reactions and the energy pathways at the molecular level. Through this experiment, students can develop expertise in Gaussian and GaussView, which are the general computing software of computational chemistry. Moreover, students can independently conduct structural optimization, frequency calculations, transition state searches, and other basic calculation operations. This experiment enables students to apply quantum chemical calculation methods when studying the general processes of different chemical reactions, thereby laying an important foundation for their future research.
We introduce an exploratory computational chemistry experiment for senior undergraduate students. By studying the reaction mechanisms of intra- and intermolecular ethanol dehydration, students can understand the role of acid catalysts in alcohol dehydration reactions and the energy pathways at the molecular level. Through this experiment, students can develop expertise in Gaussian and GaussView, which are the general computing software of computational chemistry. Moreover, students can independently conduct structural optimization, frequency calculations, transition state searches, and other basic calculation operations. This experiment enables students to apply quantum chemical calculation methods when studying the general processes of different chemical reactions, thereby laying an important foundation for their future research.
2023, 38(9): 188-195
doi: 10.3866/PKU.DXHX202211044
Abstract:
Developing a novel research method by assembling elements and equipment is a significant way of innovation in science and technology. Considering the assembly of DTA-Raman hyphenated system as an example, the modules available in a laboratory were assembled to form a differential thermal analysis (DTA) section. This section was designed to meet the practical conditions for Raman spectral measurement. The phase transition of mixed molten salts was investigated using this DTA-Raman spectroscopy hyphenated system. Through the construction and measuring process, students can understand the principle of DTA in detail and recognize the enhancement effect from the combined use of several experimental techniques. Furthermore, they will learn to establish a new research method from the available materials. Therefore, this experimental teaching case can effectively contribute to the improved creativity and scientific research ability of the students. Finally, this experiment can further improve the aspects of the DTA test platform, data acquisition unit, and phase diagram determination. Thus, sustainable innovation can be expected from this open experimental teaching project.
Developing a novel research method by assembling elements and equipment is a significant way of innovation in science and technology. Considering the assembly of DTA-Raman hyphenated system as an example, the modules available in a laboratory were assembled to form a differential thermal analysis (DTA) section. This section was designed to meet the practical conditions for Raman spectral measurement. The phase transition of mixed molten salts was investigated using this DTA-Raman spectroscopy hyphenated system. Through the construction and measuring process, students can understand the principle of DTA in detail and recognize the enhancement effect from the combined use of several experimental techniques. Furthermore, they will learn to establish a new research method from the available materials. Therefore, this experimental teaching case can effectively contribute to the improved creativity and scientific research ability of the students. Finally, this experiment can further improve the aspects of the DTA test platform, data acquisition unit, and phase diagram determination. Thus, sustainable innovation can be expected from this open experimental teaching project.
2023, 38(9): 196-201
doi: 10.3866/PKU.DXHX202211056
Abstract:
The high performance liquid chromatography (HPLC) method of UV detector-fluorescence detector (UVD-FLD) connected in series for the determination of vitamin B2 in tablets was designed as a teaching experiment. This method can overcome the limitations of common HPLC by a single detector. Through the application of this method for experimental teaching, students could not only master the basic theory and operation of HPLC, but also understand the principles and functions of UVD and FLD. Furthermore, it also improved the undergraduate students' experimental skill and comprehension.
The high performance liquid chromatography (HPLC) method of UV detector-fluorescence detector (UVD-FLD) connected in series for the determination of vitamin B2 in tablets was designed as a teaching experiment. This method can overcome the limitations of common HPLC by a single detector. Through the application of this method for experimental teaching, students could not only master the basic theory and operation of HPLC, but also understand the principles and functions of UVD and FLD. Furthermore, it also improved the undergraduate students' experimental skill and comprehension.
2023, 38(9): 202-208
doi: 10.3866/PKU.DXHX202210071
Abstract:
To improve the undergraduate understanding of supramolecular chemistry and dissipative structures and train their ability to conduct comprehensive chemical experiments, this paper proposes an experiment of dynamic reconfiguration of supramolecular assemblies that is based on guanosine 5'-monophosphate disodium salt and the urea-urease clock reaction. This experiment covers the construction approach and structural characterization of the nonequilibrium supramolecular assembly system based on the clock reaction, as well as the exploration of the mechanism of the dynamic reconfiguration of the assemblies. Integrating science and education can prompt students' interest in scientific investigation, cultivate their scientific thinking, and improve their comprehensive skills.
To improve the undergraduate understanding of supramolecular chemistry and dissipative structures and train their ability to conduct comprehensive chemical experiments, this paper proposes an experiment of dynamic reconfiguration of supramolecular assemblies that is based on guanosine 5'-monophosphate disodium salt and the urea-urease clock reaction. This experiment covers the construction approach and structural characterization of the nonequilibrium supramolecular assembly system based on the clock reaction, as well as the exploration of the mechanism of the dynamic reconfiguration of the assemblies. Integrating science and education can prompt students' interest in scientific investigation, cultivate their scientific thinking, and improve their comprehensive skills.
2023, 38(9): 209-217
doi: 10.3866/PKU.DXHX202211061
Abstract:
Herein we describe an innovative comprehensive experiment titled “Design and Evaluation of a ZIF-8/WCNT-Based Electrochemical Sensor for Nitrofurazone Determination in Experimental Teaching” used in our undergraduate program. The experiment comprises several modules, namely synthesis and characterization of Zn-MeIM metal-organic framework ZIF-8, preparation of an electrochemical sensor, optimization of experimental conditions, and development of analytical methods. The experiment involves analytical chemistry, materials chemistry, and other secondary chemistry branches. Owing to its interdisciplinary features and remarkable expansibility, the experiment is suitable for undergraduate experimental analytical chemistry teaching.
Herein we describe an innovative comprehensive experiment titled “Design and Evaluation of a ZIF-8/WCNT-Based Electrochemical Sensor for Nitrofurazone Determination in Experimental Teaching” used in our undergraduate program. The experiment comprises several modules, namely synthesis and characterization of Zn-MeIM metal-organic framework ZIF-8, preparation of an electrochemical sensor, optimization of experimental conditions, and development of analytical methods. The experiment involves analytical chemistry, materials chemistry, and other secondary chemistry branches. Owing to its interdisciplinary features and remarkable expansibility, the experiment is suitable for undergraduate experimental analytical chemistry teaching.
2023, 38(9): 218-226
doi: 10.3866/PKU.DXHX202211072
Abstract:
Graphene exhibits excellent optical and electrical properties. Therefore, it presents remarkable potential application in “carbon neutral” technologies. We have recently developed a green mechanochemical method for preparation of edge-selectively hydroxylated graphene nanosheets using persulfate as the milling reagent. The as-prepared graphene exhibited the typical intrinsic properties of graphene and good dispersity in water. The preparation process did not require organic solvents, it involved low energy consumption, and produced little eco-friendly waste. Based on the aforementioned study, we designed an experiment on the green preparation, characterization, and applications of graphene. Various instrumental analytical methods were used to explore the structure and physicochemical properties of graphene and the applications of graphene as an energy storage material. We also compared the properties of the as-prepared graphene with those of graphene samples previously reported in the literature. This experiment should cultivate student ability to comprehensively use basic chemistry knowledge to solve real-life problems, stimulate their innovative thinking, and cultivate their “green chemistry” consciousness.
Graphene exhibits excellent optical and electrical properties. Therefore, it presents remarkable potential application in “carbon neutral” technologies. We have recently developed a green mechanochemical method for preparation of edge-selectively hydroxylated graphene nanosheets using persulfate as the milling reagent. The as-prepared graphene exhibited the typical intrinsic properties of graphene and good dispersity in water. The preparation process did not require organic solvents, it involved low energy consumption, and produced little eco-friendly waste. Based on the aforementioned study, we designed an experiment on the green preparation, characterization, and applications of graphene. Various instrumental analytical methods were used to explore the structure and physicochemical properties of graphene and the applications of graphene as an energy storage material. We also compared the properties of the as-prepared graphene with those of graphene samples previously reported in the literature. This experiment should cultivate student ability to comprehensively use basic chemistry knowledge to solve real-life problems, stimulate their innovative thinking, and cultivate their “green chemistry” consciousness.
2023, 38(9): 227-233
doi: 10.3866/PKU.DXHX202211089
Abstract:
Based on the quantum chemical calculation software Gaussian 16, a computational chemistry design was carried out for the classical physical chemistry experiment “Determination of electromotive force”. The solvation free energy of Cu2+ and Zn2+ was calculated by density functional theory, and then the standard molar Gibbs free energy change of the cell reaction was computed through the thermodynamic cycle. The standard electromotive force of the Cu-Zn glavanic battery was further derived. The experiment aims to deepen students' understanding of the basic physical chemistry concept, such as standard molar Gibbs free energy, electrode potential and Nernst equation, to give full play to students' subjective initiative, and to cultivate students' abilities of experiment designing, practice and scientific thinking.
Based on the quantum chemical calculation software Gaussian 16, a computational chemistry design was carried out for the classical physical chemistry experiment “Determination of electromotive force”. The solvation free energy of Cu2+ and Zn2+ was calculated by density functional theory, and then the standard molar Gibbs free energy change of the cell reaction was computed through the thermodynamic cycle. The standard electromotive force of the Cu-Zn glavanic battery was further derived. The experiment aims to deepen students' understanding of the basic physical chemistry concept, such as standard molar Gibbs free energy, electrode potential and Nernst equation, to give full play to students' subjective initiative, and to cultivate students' abilities of experiment designing, practice and scientific thinking.
2023, 38(9): 234-241
doi: 10.3866/PKU.DXHX202212037
Abstract:
Aiming at the demand of the “dual carbon strategy”, we have designed an inexpensive and highly safe zinc-manganese dioxide (Zn-MnO2) secondary batteries, and formed a standardized comprehensive physical chemistry experiment. Herein, α-MnO2 was prepared firstly using a hydrothermal method. After that, the structure and morphology of α-MnO2 were characterized using X-ray diffraction and scanning electron microscopy. Furthermore, the Zn-MnO2 secondary batteries were prepared using α-MnO2 cathodes and Zn flake anodes, and the electrochemical performance was evaluated using cyclic voltammetry, rate, and long cycling experiments. We believe that this experiment can promote transformation of popular research topics into comprehensive teaching experiments and facilitate implementation of laboratory findings into daily life. Moreover, by integrating chemical material synthesis with characterization and electrochemical performance testing, modular teaching can be used to meet various teaching and learning styles. In addition, the combination of inquiry-based learning and comprehensive experiments can improve students' interest and hands-on activities. Our approach integrates ideological and political elements, highlights the green chemistry concept, increases students' awareness of safe and pollution-free chemical experiments, and promotes the idea of sustainable development.
Aiming at the demand of the “dual carbon strategy”, we have designed an inexpensive and highly safe zinc-manganese dioxide (Zn-MnO2) secondary batteries, and formed a standardized comprehensive physical chemistry experiment. Herein, α-MnO2 was prepared firstly using a hydrothermal method. After that, the structure and morphology of α-MnO2 were characterized using X-ray diffraction and scanning electron microscopy. Furthermore, the Zn-MnO2 secondary batteries were prepared using α-MnO2 cathodes and Zn flake anodes, and the electrochemical performance was evaluated using cyclic voltammetry, rate, and long cycling experiments. We believe that this experiment can promote transformation of popular research topics into comprehensive teaching experiments and facilitate implementation of laboratory findings into daily life. Moreover, by integrating chemical material synthesis with characterization and electrochemical performance testing, modular teaching can be used to meet various teaching and learning styles. In addition, the combination of inquiry-based learning and comprehensive experiments can improve students' interest and hands-on activities. Our approach integrates ideological and political elements, highlights the green chemistry concept, increases students' awareness of safe and pollution-free chemical experiments, and promotes the idea of sustainable development.
2023, 38(9): 242-251
doi: 10.3866/PKU.DXHX202212023
Abstract:
The urea oxidation reaction (UOR) was comprehensively studied using electrochemical method, including detailed cyclic voltammetry analyses of the UOR behavior on Ni in a standard three-electrode system. The data were analyzed to extract important physical and chemical parameters of the reaction such as the diffusion coefficient, transfer coefficient, and reaction order. This experiment combined current electrocatalysis research with undergraduate electroanalysis courses and the kinetics of chemical and electrochemical reactions. A two-electrode system was used to construct a urea-assisted electrolyzer for hydrogen production to demonstrate the practical application of this system. This experiment was designed to encourage undergraduate students to use their basic knowledge to solve practical problems and stimulate their enthusiasm for scientific research.
The urea oxidation reaction (UOR) was comprehensively studied using electrochemical method, including detailed cyclic voltammetry analyses of the UOR behavior on Ni in a standard three-electrode system. The data were analyzed to extract important physical and chemical parameters of the reaction such as the diffusion coefficient, transfer coefficient, and reaction order. This experiment combined current electrocatalysis research with undergraduate electroanalysis courses and the kinetics of chemical and electrochemical reactions. A two-electrode system was used to construct a urea-assisted electrolyzer for hydrogen production to demonstrate the practical application of this system. This experiment was designed to encourage undergraduate students to use their basic knowledge to solve practical problems and stimulate their enthusiasm for scientific research.
2023, 38(9): 252-262
doi: 10.3866/PKU.DXHX202212001
Abstract:
The semi-synthesis and antibacterial study of penicillin V potassium is primarily an interdisciplinary experiment. Currently, only a few foreign universities such as the Massachusetts Institute of Technology (MIT) allow undergraduate students to conduct this experiment. To incorporate a research-like environment into teaching experiments and enable students to develop scientific thinking, the following improvements were made to the experiment: 1) A circulating condensing device was designed and built, and low-temperature control was introduced to improve the stability of the products and effectively reduce the formation of by-products. 2) Absolute ethyl alcohol was added to remove the by-products based on solubility difference. 3) The minimum inhibitory concentration of penicillin was determined using the microbroth dilution method, and antibiotic sensitivity was determined using the Oxford penicillin cup method. 4) The effects of penicillin on the integrity of bacterial cell walls were characterized via wheat germ agglutinin fluorescent labeling combined with confocal fluorescence microscopy. This comprehensive experiment, which combines several important multidisciplinary concepts, can develop students' skills in integrated analysis and increase their interest in scientific research.
The semi-synthesis and antibacterial study of penicillin V potassium is primarily an interdisciplinary experiment. Currently, only a few foreign universities such as the Massachusetts Institute of Technology (MIT) allow undergraduate students to conduct this experiment. To incorporate a research-like environment into teaching experiments and enable students to develop scientific thinking, the following improvements were made to the experiment: 1) A circulating condensing device was designed and built, and low-temperature control was introduced to improve the stability of the products and effectively reduce the formation of by-products. 2) Absolute ethyl alcohol was added to remove the by-products based on solubility difference. 3) The minimum inhibitory concentration of penicillin was determined using the microbroth dilution method, and antibiotic sensitivity was determined using the Oxford penicillin cup method. 4) The effects of penicillin on the integrity of bacterial cell walls were characterized via wheat germ agglutinin fluorescent labeling combined with confocal fluorescence microscopy. This comprehensive experiment, which combines several important multidisciplinary concepts, can develop students' skills in integrated analysis and increase their interest in scientific research.
2023, 38(9): 263-271
doi: 10.3866/PKU.DXHX202212027
Abstract:
In this experiment, the dehydrogenative coupling of p-ethyl anisole and 2-(1-(4-methoxyphenyl)ethyl)-5-phenyl-2H-tetrazole is realized through electro-oxidation to generate C―N bonds and synthesize a benzyl-azolated aromatic product. The reaction is simple, safe, and efficient. It also integrates the experimental exploration of green chemistry concepts and organic synthetic methodology. As an undergraduate teaching experiment, it not only covers the basic operation of various organic experiments, but also includes reaction monitoring, purification, structural characterization, and other important procedures. Using this experimental protocol, micro-class learning, extended exercises on the progress of C―H activation, interesting experiments, as well as effective synergy of theoretical knowledge and synthetic practice are realized. Thus, the comprehensive ability of undergraduates majoring in chemistry and pharmacy to solve complex organic synthesis problems is improved, and the research foundation to nurture chemistry talents is further established.
In this experiment, the dehydrogenative coupling of p-ethyl anisole and 2-(1-(4-methoxyphenyl)ethyl)-5-phenyl-2H-tetrazole is realized through electro-oxidation to generate C―N bonds and synthesize a benzyl-azolated aromatic product. The reaction is simple, safe, and efficient. It also integrates the experimental exploration of green chemistry concepts and organic synthetic methodology. As an undergraduate teaching experiment, it not only covers the basic operation of various organic experiments, but also includes reaction monitoring, purification, structural characterization, and other important procedures. Using this experimental protocol, micro-class learning, extended exercises on the progress of C―H activation, interesting experiments, as well as effective synergy of theoretical knowledge and synthetic practice are realized. Thus, the comprehensive ability of undergraduates majoring in chemistry and pharmacy to solve complex organic synthesis problems is improved, and the research foundation to nurture chemistry talents is further established.
2023, 38(9): 272-279
doi: 10.3866/PKU.DXHX202211040
Abstract:
This study introduced an innovative, comprehensive experiment of organic chemistry — “the experimental teaching scheme of learning the Hammett equation by Suzuki coupling reaction”. The relationship curve of the Hammett equation was further obtained by exploring the influence of different substituted substrates on the reaction rate of the Suzuki coupling reaction. The results showed that the reaction rate was slowed down by the electron-withdrawing substituents on phenylboronic acid and accelerated by the electron-donating substituents. The influence of the metallization process on the Suzuki coupling reaction was also explored. In the process of literature research, experimental design, experimental operation, result analysis and report writing, students can learn the basic principle of Suzuki coupling reaction and understand the significance of the Hammett equation. The comprehensive experimental project is helpful to stimulate students' interest in scientific research of organic chemistry and improve their comprehensive quality.
This study introduced an innovative, comprehensive experiment of organic chemistry — “the experimental teaching scheme of learning the Hammett equation by Suzuki coupling reaction”. The relationship curve of the Hammett equation was further obtained by exploring the influence of different substituted substrates on the reaction rate of the Suzuki coupling reaction. The results showed that the reaction rate was slowed down by the electron-withdrawing substituents on phenylboronic acid and accelerated by the electron-donating substituents. The influence of the metallization process on the Suzuki coupling reaction was also explored. In the process of literature research, experimental design, experimental operation, result analysis and report writing, students can learn the basic principle of Suzuki coupling reaction and understand the significance of the Hammett equation. The comprehensive experimental project is helpful to stimulate students' interest in scientific research of organic chemistry and improve their comprehensive quality.
2023, 38(9): 280-286
doi: 10.3866/PKU.DXHX202211018
Abstract:
Herein we comment on and discuss the article mentioned in the title, “Understanding the Effect of Solvents on the Nucleophilicity of CH3O−/CH3S− Using Quantum Chemical Calculations”, which was published in this journal. By implementing the recent advances in solvent effect, we intend to use quantum chemistry to improve the understanding of students towards solvent effect on ion-molecular nucleophilic substitution (SN2) reactions. We have added visualization examples to demonstrate the different properties of nucleophiles CH3O− and CH3S−, uncovered the nature of how solvation weakens the nucleophilicity through comparing the potential energy profiles in gas and liquid phases, considered different types of solvents, and employed frontier molecular orbital model to illustrate the solvation effect. We anticipate the work herein can improve this teaching case as a model for organic chemistry assisted by computational chemistry.
Herein we comment on and discuss the article mentioned in the title, “Understanding the Effect of Solvents on the Nucleophilicity of CH3O−/CH3S− Using Quantum Chemical Calculations”, which was published in this journal. By implementing the recent advances in solvent effect, we intend to use quantum chemistry to improve the understanding of students towards solvent effect on ion-molecular nucleophilic substitution (SN2) reactions. We have added visualization examples to demonstrate the different properties of nucleophiles CH3O− and CH3S−, uncovered the nature of how solvation weakens the nucleophilicity through comparing the potential energy profiles in gas and liquid phases, considered different types of solvents, and employed frontier molecular orbital model to illustrate the solvation effect. We anticipate the work herein can improve this teaching case as a model for organic chemistry assisted by computational chemistry.
2023, 38(9): 287-292
doi: 10.3866/PKU.DXHX202211087
Abstract:
Distillation is a typical unit operation for separating liquid mixtures. The temperature–composition curve in the gas–liquid equilibrium phase diagram is important for guiding distillation operations. An ideal liquid mixture with two components was utilized as the study system in this work. We proved that the temperature–composition curve (T–x or T–y) of ideal liquid mixtures with two components is strictly monotonic, regardless of whether the saturated vapor pressure of liquid conforms to the Clausius-Clapeyron equation or Antoine equation. This means that the bubble point temperature and dew point temperature increase monotonously with the increase of lowly volatile substance content.
Distillation is a typical unit operation for separating liquid mixtures. The temperature–composition curve in the gas–liquid equilibrium phase diagram is important for guiding distillation operations. An ideal liquid mixture with two components was utilized as the study system in this work. We proved that the temperature–composition curve (T–x or T–y) of ideal liquid mixtures with two components is strictly monotonic, regardless of whether the saturated vapor pressure of liquid conforms to the Clausius-Clapeyron equation or Antoine equation. This means that the bubble point temperature and dew point temperature increase monotonously with the increase of lowly volatile substance content.
2023, 38(9): 293-300
doi: 10.3866/PKU.DXHX202212024
Abstract:
Cyclic voltammetry (CV) is one of the most important electrochemical research methods; however, many instrumental analysis textbooks only briefly discuss CV operating principles.The electrode reaction processes are not discussed in-depth; consequently, students can lack the necessary skills to interpret CV curves. This study analyzed the electrode processes to determine the changes in the concentration of electroactive materials at the electrode/interface. Furthermore, the characteristics of the CV curve and the effect of concentration and scanning speed on the CV curve are also described. Finally, the philosophical principles contained in CV are discussed. This study can provide reference information for both peer teaching and student learning.
Cyclic voltammetry (CV) is one of the most important electrochemical research methods; however, many instrumental analysis textbooks only briefly discuss CV operating principles.The electrode reaction processes are not discussed in-depth; consequently, students can lack the necessary skills to interpret CV curves. This study analyzed the electrode processes to determine the changes in the concentration of electroactive materials at the electrode/interface. Furthermore, the characteristics of the CV curve and the effect of concentration and scanning speed on the CV curve are also described. Finally, the philosophical principles contained in CV are discussed. This study can provide reference information for both peer teaching and student learning.
2023, 38(9): 301-307
doi: 10.3866/PKU.DXHX202211014
Abstract:
Using the liquid-gas phase transition as an example, this study discussed how to achieve the triune teaching goal better for physical chemistry course, that is, to simultaneously cultivate the “knowledge-ability-quality” of the students.
Using the liquid-gas phase transition as an example, this study discussed how to achieve the triune teaching goal better for physical chemistry course, that is, to simultaneously cultivate the “knowledge-ability-quality” of the students.
2023, 38(9): 308-312
doi: 10.3866/PKU.DXHX202211026
Abstract:
In this study, we used the multireference complete active space perturbation theory (CASPT2) method to calculate the equilibrium nuclear distances and wave functions of the 2nd-row homonuclear diatomic molecules in the ground-state. The wave functions of Li2, N2, O2, and F2 molecules are dominated by a single electron configuration; thus, their bonding properties can be analyzed on the base of a single configuration. In contrast, Be2, B2, and C2 molecules have obvious multiconfigurational characteristics, so considering the contributions of multiple configurations is necessary to obtain consistent results with the experimental observations. By introducing the contribution of the second most important configuration in the calculation of bond order or using the fractional electron occupation number of natural orbitals, we have rationalized the existence of the Be2 molecule and its non-zero Be―Be bond order. Additionally, we determined that the bond orders in B2 and C2 are 1–2 and 2–3, respectively. The results obtained here can be used as a supplement to the simple molecular orbital theory to help students understand the structure and bonding nature of diatomic molecules. The present work emphasizes the necessity of multiconfiguration characteristics of wave functions to understand molecular structure, and verifies the feasibility of introducing relatively simple, cost effective, multireference calculations to assist in teaching.
In this study, we used the multireference complete active space perturbation theory (CASPT2) method to calculate the equilibrium nuclear distances and wave functions of the 2nd-row homonuclear diatomic molecules in the ground-state. The wave functions of Li2, N2, O2, and F2 molecules are dominated by a single electron configuration; thus, their bonding properties can be analyzed on the base of a single configuration. In contrast, Be2, B2, and C2 molecules have obvious multiconfigurational characteristics, so considering the contributions of multiple configurations is necessary to obtain consistent results with the experimental observations. By introducing the contribution of the second most important configuration in the calculation of bond order or using the fractional electron occupation number of natural orbitals, we have rationalized the existence of the Be2 molecule and its non-zero Be―Be bond order. Additionally, we determined that the bond orders in B2 and C2 are 1–2 and 2–3, respectively. The results obtained here can be used as a supplement to the simple molecular orbital theory to help students understand the structure and bonding nature of diatomic molecules. The present work emphasizes the necessity of multiconfiguration characteristics of wave functions to understand molecular structure, and verifies the feasibility of introducing relatively simple, cost effective, multireference calculations to assist in teaching.
2023, 38(9): 313-321
doi: 10.3866/PKU.DXHX202210040
Abstract:
This paper mainly introduces the way of optimizating synthesis process of the [Ni(Me3en)(acac)]BPh4 complex and the preliminary results of initial effort. On the basis of guiding students to understand the synthetic principle, conditions and process of [Ni(Me3en)(acac)]BPh4 complex, we take absorbing the free water on the solid surface of Ni(NO3)2·6H2O as the starting point, the effect of water on the synthetic system was discussed. Combined with the experimental principle, synthetic process and conditions, we propose several different synthetic approaches, and explore and verify them through the experiment. Through the above optimization processes, students' problem awareness and ability to solve problems can be cultivated, and we lay the foundation for the experiment to face students with different levels, different teaching needs and different teaching purposes.
This paper mainly introduces the way of optimizating synthesis process of the [Ni(Me3en)(acac)]BPh4 complex and the preliminary results of initial effort. On the basis of guiding students to understand the synthetic principle, conditions and process of [Ni(Me3en)(acac)]BPh4 complex, we take absorbing the free water on the solid surface of Ni(NO3)2·6H2O as the starting point, the effect of water on the synthetic system was discussed. Combined with the experimental principle, synthetic process and conditions, we propose several different synthetic approaches, and explore and verify them through the experiment. Through the above optimization processes, students' problem awareness and ability to solve problems can be cultivated, and we lay the foundation for the experiment to face students with different levels, different teaching needs and different teaching purposes.
2023, 38(9): 322-328
doi: 10.3866/PKU.DXHX202212020
Abstract:
Problem 5 of the 51th International Chemistry Olympiad is analyzed. Based on the nanomachines, this problem examined the properties of azo compounds as well as application of Lambert-Beer law, chemical equilibrium and chemical dynamics.
Problem 5 of the 51th International Chemistry Olympiad is analyzed. Based on the nanomachines, this problem examined the properties of azo compounds as well as application of Lambert-Beer law, chemical equilibrium and chemical dynamics.
