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2017 Volume 34 Issue 2
2017, 34(2): 123-138
doi: 10.11944/j.issn.1000-0518.2017.02.160282
Abstract:
β-Cyclodextrin (β-CD) is a class of cyclic oligosaccharide which consists of seven D-galactose units linked by α-1, 4-glycosidic bonds. β-CD has a rigid and cone-like molecular structure with hydrophilic outer surface and hydrophobic inner cavity. Recently, unprecedented progress about the preparation and application of supramolecular system based on β-CD has been made. In this paper, the synthesis of derivatives, oligomers and polymers of β-CD, molecular assemblies based on β-CD, and their latest application of supramolecular system that uses β-CD and its modifier as host in drug delivery, gene transfer, catalytic reaction, pollution control and so on, are reviewed. Until now, studies on basic properties of β-CD are becoming mature, but there are still some realistic problems remaining to be solved. With further studies, wider and deeper applications of β-CD may be finally achieved in various fields.
β-Cyclodextrin (β-CD) is a class of cyclic oligosaccharide which consists of seven D-galactose units linked by α-1, 4-glycosidic bonds. β-CD has a rigid and cone-like molecular structure with hydrophilic outer surface and hydrophobic inner cavity. Recently, unprecedented progress about the preparation and application of supramolecular system based on β-CD has been made. In this paper, the synthesis of derivatives, oligomers and polymers of β-CD, molecular assemblies based on β-CD, and their latest application of supramolecular system that uses β-CD and its modifier as host in drug delivery, gene transfer, catalytic reaction, pollution control and so on, are reviewed. Until now, studies on basic properties of β-CD are becoming mature, but there are still some realistic problems remaining to be solved. With further studies, wider and deeper applications of β-CD may be finally achieved in various fields.
2017, 34(2): 146-150
doi: 10.11944/j.issn.1000-0518.2017.02.160163
Abstract:
Dimethyl 6, 6'-dimethyl-[2, 2'-bipyridine]-4, 4'-dicarboxylate was synthesized in two steps from methyl 6-methyl-2-hydroxypyridine-4-carboxylate. The first step was the preparation of methyl 2-methyl-6-[(p-toluenesulfonyl) oxy]pyridine-4-carboxylate by esterification. The second step was to prepare the target product by nickel complex catalyzed homocoupling reaction. Several other factors which affected the reaction such as material proportion, reaction temperature and addition order were investigated. When the reaction was carried out under the optimal conditions, 77% yield was achieved. The products were characterized by nuclear magnetic resonance (NMR), Fourier transform infrared spectrometer (FTIR), mass spectrometry (MS) and differential scanning calorimetry (DSC) to prove the reliability of the synthetic method. This structure can fully satisfy the need of chelating agent intermediate for homogeneous time-resolved fluoroimmunoassay (HTRF), which has been succeeded in prectical applications.
Dimethyl 6, 6'-dimethyl-[2, 2'-bipyridine]-4, 4'-dicarboxylate was synthesized in two steps from methyl 6-methyl-2-hydroxypyridine-4-carboxylate. The first step was the preparation of methyl 2-methyl-6-[(p-toluenesulfonyl) oxy]pyridine-4-carboxylate by esterification. The second step was to prepare the target product by nickel complex catalyzed homocoupling reaction. Several other factors which affected the reaction such as material proportion, reaction temperature and addition order were investigated. When the reaction was carried out under the optimal conditions, 77% yield was achieved. The products were characterized by nuclear magnetic resonance (NMR), Fourier transform infrared spectrometer (FTIR), mass spectrometry (MS) and differential scanning calorimetry (DSC) to prove the reliability of the synthetic method. This structure can fully satisfy the need of chelating agent intermediate for homogeneous time-resolved fluoroimmunoassay (HTRF), which has been succeeded in prectical applications.
2017, 34(2): 151-157
doi: 10.11944/j.issn.1000-0518.2017.02.160203
Abstract:
9, 10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), a versatile heterocyclic organophosphorus compound, is widely used for halogen-free fire retarding. In order to improve the synthesis process of DOPO, much effort has been devoted to analyzing these four reactions:esterification, acylation, hydrolysis and cyclization. However, due to the absence of suitable methods or instruments for analysis, it only led to some ambiguous results. In this paper, 31P nuclear magnetic resonance (31P NMR) and measuring the temperature of alkali solutions for HCl absorption were adopted to characterize the reactions to obtain precise optimized conditions for esterification and acylation. By 31P NMR, the effect of esterification temperature, the ratio of o-phenylphenol (OPP) to PCl3 and the addition order of reactants on the component content of products from esterification was discussed, and conditions for the highest content of o-phenyl ester phenoxy phosphorus dichloride (CC) were revealed as 80℃, a feeding order of adding OPP into PCl3 with 25%~50% extra PCl3. The dependence of the content of 6-chloro-dibenzo[c.e] [1, 2]-oxaphosphorine (CDOP) in products from acylation on the component content of products from esterification was also established. The acylation was investigated by measuring temperature change of aqueous NaOH when it absorbed HCl released from the reaction to give desirable reaction temperature and dosage of catalysis. In the present work, when 0.2 g catalyst is used, acylation of 0.2 mol esterified products does not proceed at 150℃, but has increased rate at higher temperatures and can finish in 4 h at 180℃ and 1.5 h at 190℃; a catalyst dosage of 1~1.5 g catalyst per mol OPP is practicable for acylation at 180℃ which can complete in 3~4 h.
9, 10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), a versatile heterocyclic organophosphorus compound, is widely used for halogen-free fire retarding. In order to improve the synthesis process of DOPO, much effort has been devoted to analyzing these four reactions:esterification, acylation, hydrolysis and cyclization. However, due to the absence of suitable methods or instruments for analysis, it only led to some ambiguous results. In this paper, 31P nuclear magnetic resonance (31P NMR) and measuring the temperature of alkali solutions for HCl absorption were adopted to characterize the reactions to obtain precise optimized conditions for esterification and acylation. By 31P NMR, the effect of esterification temperature, the ratio of o-phenylphenol (OPP) to PCl3 and the addition order of reactants on the component content of products from esterification was discussed, and conditions for the highest content of o-phenyl ester phenoxy phosphorus dichloride (CC) were revealed as 80℃, a feeding order of adding OPP into PCl3 with 25%~50% extra PCl3. The dependence of the content of 6-chloro-dibenzo[c.e] [1, 2]-oxaphosphorine (CDOP) in products from acylation on the component content of products from esterification was also established. The acylation was investigated by measuring temperature change of aqueous NaOH when it absorbed HCl released from the reaction to give desirable reaction temperature and dosage of catalysis. In the present work, when 0.2 g catalyst is used, acylation of 0.2 mol esterified products does not proceed at 150℃, but has increased rate at higher temperatures and can finish in 4 h at 180℃ and 1.5 h at 190℃; a catalyst dosage of 1~1.5 g catalyst per mol OPP is practicable for acylation at 180℃ which can complete in 3~4 h.
2017, 34(2): 158-162
doi: 10.11944/j.issn.1000-0518.2017.02.160133
Abstract:
2, 2'-Dithiobisbenzanilide was synthesized with a total yield of 80% via oxidative condensation and acylation reaction. The title compound was extensively characterized by HRMS, NMR and single crystal X-ray diffraction. The single crystal X-ray structural analysis reveals that the crystal packing of the compound was stabilized by intramolecular C-H…O and C-H…S, intermolecular N-H…O and C-H…O interactions, and even Van der Waals force. The results show that the novel method is suitable for scale-up production with the advantages of easily obtained raw materials, easily conducted procedure and relatively high yield. Moreover, the compound shows excellent inhibitory activity against Botrytis cinerea, Sclerotinia sclerotiorum and Rhizoctonia solani.
2, 2'-Dithiobisbenzanilide was synthesized with a total yield of 80% via oxidative condensation and acylation reaction. The title compound was extensively characterized by HRMS, NMR and single crystal X-ray diffraction. The single crystal X-ray structural analysis reveals that the crystal packing of the compound was stabilized by intramolecular C-H…O and C-H…S, intermolecular N-H…O and C-H…O interactions, and even Van der Waals force. The results show that the novel method is suitable for scale-up production with the advantages of easily obtained raw materials, easily conducted procedure and relatively high yield. Moreover, the compound shows excellent inhibitory activity against Botrytis cinerea, Sclerotinia sclerotiorum and Rhizoctonia solani.
2017, 34(2): 163-171
doi: 10.11944/j.issn.1000-0518.2017.02.160183
Abstract:
Tris (o-methylbenzyl) tin thiosalicylate (1) and di (m-fluorobenzyl) tin thiosalicylate (2) have been synthesized. Crystal structures of the complexes were determined by X-ray diffraction. Crystal 1 belongs to the triclinic space group P1 with a=1.00221(5) nm, b=1.48934(8) nm, c=1.71789(9) nm, α=78.3120(10)°, β=85.6560(10)°, γ=80.2580(10)°, V=2.4725(2) nm3, Z=2, Dc=1.371 g/cm3, μ(MoKα)=10.91 cm-1, F(000)=1040, R1=0.0439, wR2=0.1119. Crystal 2 belongs to the monoclinic space group P21/n with a=1.17827(5) nm, b=2.11945(9) nm, c=1.55970(7) nm, β=93.4510(10)°, V=3.8880(3) nm3, Z=4, Dc=1.671 g/cm3, μ(MoKα)=14.53 cm-1, F(000)=1936, R1=0.0323, wR2=0.0927. The tin atoms in complexes 1 and 2 have four coordinates in a distorted tetrahedral configuration and five coordinates in a distorted trigonal bipyramidal configuration, respectively. Further more, the thermal stability and electrochemical and anticancer activity of the complexes were tested. The results show that complexes 1 and 2 are stable below 152℃ and below 195℃, respectively, and show irreversible redox process. Complexes 1 and 2 display in vitro anti-tumor activity against five human tumor cell lines Colo205, Hep G2, MCF-7, Hela and NCI-H460, and the anti-tumor activity of complex 2 is higher than that of complex 1.
Tris (o-methylbenzyl) tin thiosalicylate (1) and di (m-fluorobenzyl) tin thiosalicylate (2) have been synthesized. Crystal structures of the complexes were determined by X-ray diffraction. Crystal 1 belongs to the triclinic space group P1 with a=1.00221(5) nm, b=1.48934(8) nm, c=1.71789(9) nm, α=78.3120(10)°, β=85.6560(10)°, γ=80.2580(10)°, V=2.4725(2) nm3, Z=2, Dc=1.371 g/cm3, μ(MoKα)=10.91 cm-1, F(000)=1040, R1=0.0439, wR2=0.1119. Crystal 2 belongs to the monoclinic space group P21/n with a=1.17827(5) nm, b=2.11945(9) nm, c=1.55970(7) nm, β=93.4510(10)°, V=3.8880(3) nm3, Z=4, Dc=1.671 g/cm3, μ(MoKα)=14.53 cm-1, F(000)=1936, R1=0.0323, wR2=0.0927. The tin atoms in complexes 1 and 2 have four coordinates in a distorted tetrahedral configuration and five coordinates in a distorted trigonal bipyramidal configuration, respectively. Further more, the thermal stability and electrochemical and anticancer activity of the complexes were tested. The results show that complexes 1 and 2 are stable below 152℃ and below 195℃, respectively, and show irreversible redox process. Complexes 1 and 2 display in vitro anti-tumor activity against five human tumor cell lines Colo205, Hep G2, MCF-7, Hela and NCI-H460, and the anti-tumor activity of complex 2 is higher than that of complex 1.
2017, 34(2): 172-179
doi: 10.11944/j.issn.1000-0518.2017.02.160146
Abstract:
Aryl palladium complex (bt-DTT) Pd (PCy3)2Br was synthesized by oxidative addition of 5-bromo-2-trimethylsilanyl-dithieno[2, 3-b:2', 3'-d]thiophene (bt-DTT-Br) to bis (tericlohexylphosphine) palladium (Pd (PCy3)2). X-ray crystal structure analysis reveals that the complex adopts a nearly square-planar geometry around central Pd atom with the expected trans configuration of the phosphine ligands. The complex can initiate the polymerization of AB-type fluorene monomer under heating conditions to afford the polyfluorene with the defined end group of aryl group bt-DTT derived from the complex (bt-DTT) Pd (PCy3)2Br. The similar conjugated polymers can also be prepared by employing the aryl palladium complexes in situ generated from bt-DTT-Br/Pd (0)-species as initiators. Polymerization of AB-type fluorene monomers is achieved at room temperature to give the single polyfluorene with the well-defined end groups while initiators are the complexes with the ancillary ligand of tris(2-methylphenyl) phosphine (P (o-tol)3) or tri-tert-butylphosphine (P (t-Bu)3). Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectra confirm that the polymers bear a bt-DTT group at one end and a Br/H atom or end-capping group at the other end. Gel permeation chromatography (GPC) analyses demonstrate that molecular mass of polymers increases linearly with increase of the molar ratio of monomer to catalyst, indicating that the polymerizations proceed through the catalyst-transfer mechanism.
Aryl palladium complex (bt-DTT) Pd (PCy3)2Br was synthesized by oxidative addition of 5-bromo-2-trimethylsilanyl-dithieno[2, 3-b:2', 3'-d]thiophene (bt-DTT-Br) to bis (tericlohexylphosphine) palladium (Pd (PCy3)2). X-ray crystal structure analysis reveals that the complex adopts a nearly square-planar geometry around central Pd atom with the expected trans configuration of the phosphine ligands. The complex can initiate the polymerization of AB-type fluorene monomer under heating conditions to afford the polyfluorene with the defined end group of aryl group bt-DTT derived from the complex (bt-DTT) Pd (PCy3)2Br. The similar conjugated polymers can also be prepared by employing the aryl palladium complexes in situ generated from bt-DTT-Br/Pd (0)-species as initiators. Polymerization of AB-type fluorene monomers is achieved at room temperature to give the single polyfluorene with the well-defined end groups while initiators are the complexes with the ancillary ligand of tris(2-methylphenyl) phosphine (P (o-tol)3) or tri-tert-butylphosphine (P (t-Bu)3). Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectra confirm that the polymers bear a bt-DTT group at one end and a Br/H atom or end-capping group at the other end. Gel permeation chromatography (GPC) analyses demonstrate that molecular mass of polymers increases linearly with increase of the molar ratio of monomer to catalyst, indicating that the polymerizations proceed through the catalyst-transfer mechanism.
2017, 34(2): 180-186
doi: 10.11944/j.issn.1000-0518.2017.02.160193
Abstract:
In order to explore the melting and crystallization behaviors of polyoxymethylene (POM) with the addition of 4, 4'-thiobisphenol (TDP), a series of POM/TDP alloys was prepared by melt blending of POM and TDP. The melting, crystallization behavior and crystal structure were studied by differential scanning calorimeter (DSC) and wide-angle X-ray diffraction (WAXD). The results demonstrate that POM has a less compact crystal structure with addition of TDP, which makes the melt crystallization temperatures (Tc), heat of crystallization (ΔHc), melting temperatures (Tm) and heat of fusion (ΔHm) decrease with the increase of the content of TDP. Incorporation of TDP with a mass fraction of 30% leads to reduction of melting point and crystallization temperature by 15.2℃ and 12.8℃ compared with pure POM, respectively. Meanwhile, it is worth noting that the crystallization time of POM increases with the increase of the content of TDP, the crystallization rate decreases, and crystallization activation energy increases gradually during isothermal crystallization process. The addition of TDP does not influence the crystal structure of POM, but has a great influence on the crystallization and melting behaviors of POM.
In order to explore the melting and crystallization behaviors of polyoxymethylene (POM) with the addition of 4, 4'-thiobisphenol (TDP), a series of POM/TDP alloys was prepared by melt blending of POM and TDP. The melting, crystallization behavior and crystal structure were studied by differential scanning calorimeter (DSC) and wide-angle X-ray diffraction (WAXD). The results demonstrate that POM has a less compact crystal structure with addition of TDP, which makes the melt crystallization temperatures (Tc), heat of crystallization (ΔHc), melting temperatures (Tm) and heat of fusion (ΔHm) decrease with the increase of the content of TDP. Incorporation of TDP with a mass fraction of 30% leads to reduction of melting point and crystallization temperature by 15.2℃ and 12.8℃ compared with pure POM, respectively. Meanwhile, it is worth noting that the crystallization time of POM increases with the increase of the content of TDP, the crystallization rate decreases, and crystallization activation energy increases gradually during isothermal crystallization process. The addition of TDP does not influence the crystal structure of POM, but has a great influence on the crystallization and melting behaviors of POM.
2017, 34(2): 187-194
doi: 10.11944/j.issn.1000-0518.2017.02.160118
Abstract:
The effects of mass concentration and salinity on the viscoelasticity of three temperature-tolerant and salt-resistant flooding polymers (high molecular mass polyacrylamide (HPAM), sulfonated polyacrylamide (S-HPAM) and hydrophobic associating polyacrylamide (A-HPAM)), were investigated through the dynamic and steady state shear test at 85℃. The results show that the higher the mass concentration, the higher the storage modulus (G') and the loss modulus (G″). The apparent viscosity of polymer solutions decreases with the increase of the shear rate. The normal stress difference (N1) of polymer solutions was calculated by using dynamic experimental data. With the increase of the solution concentration, N1 gradually increases. With the increase of salinity, N1 appears different salt sensitive areas, which shows that elastic responses of polymer solutions to salinity are different. The study provides the theoretical reference for the choice and development of flooding polymers of high temperature and high salt reservoir.
The effects of mass concentration and salinity on the viscoelasticity of three temperature-tolerant and salt-resistant flooding polymers (high molecular mass polyacrylamide (HPAM), sulfonated polyacrylamide (S-HPAM) and hydrophobic associating polyacrylamide (A-HPAM)), were investigated through the dynamic and steady state shear test at 85℃. The results show that the higher the mass concentration, the higher the storage modulus (G') and the loss modulus (G″). The apparent viscosity of polymer solutions decreases with the increase of the shear rate. The normal stress difference (N1) of polymer solutions was calculated by using dynamic experimental data. With the increase of the solution concentration, N1 gradually increases. With the increase of salinity, N1 appears different salt sensitive areas, which shows that elastic responses of polymer solutions to salinity are different. The study provides the theoretical reference for the choice and development of flooding polymers of high temperature and high salt reservoir.
2017, 34(2): 195-203
doi: 10.11944/j.issn.1000-0518.2017.02.160189
Abstract:
Improving flame retardant properties of wood plastic composite material (WPC) has become one of the research hotspots of WPC in recent years. In this paper, the flame-retardant synergistic effects of eight kinds of synergists on intumescent flame retardants (IFRs, m(polyphosphate, APP):m(pentaerythritol, PER)=2:1) were studied by two rounds of orthogonal experiments. The synergist group MgO/EG (expandable graphite)/SiO2 with a significant synergistic flame retardant effect on the IFRs was obtained. The composition of MgO/EG/SiO2 is m(MgO):m(EG):m(SiO2)=1:5:5, optimum proportion of m(IFRs):m(MgO/EG/SiO2) is 1:0.18. The influence of IFRs and MgO/EG/SiO2 on thermal stability and flame-retardant properties of polypropylene based wood-plastics composite (WPC) was evaluated by thermogravimetric analysis (TGA) and cone calorimetry analysis (CONE). The results show that adding IFRs and MgO/EG/SiO2 to WPC can improve its thermal stability effectively, and the char residue of WPC/IFRs/MgO/EG/SiO2 at 600℃ reaches to 22.42%. The peak heat release rate (PHRR), the total heat release (THR) and total smoke production release (TSP) of WPC/IFRs reduce by 19.0%, 8.7% and 22.1%, respectively, compared with WPC. MgO/EG/SiO2 can further improve the flame retardant efficiency of IFRs, and the PHRR and THR of WPC/IFRs/MgO/EG/SiO2 drop by 33.0% and 13.8%, respectively, compared with WPC.
Improving flame retardant properties of wood plastic composite material (WPC) has become one of the research hotspots of WPC in recent years. In this paper, the flame-retardant synergistic effects of eight kinds of synergists on intumescent flame retardants (IFRs, m(polyphosphate, APP):m(pentaerythritol, PER)=2:1) were studied by two rounds of orthogonal experiments. The synergist group MgO/EG (expandable graphite)/SiO2 with a significant synergistic flame retardant effect on the IFRs was obtained. The composition of MgO/EG/SiO2 is m(MgO):m(EG):m(SiO2)=1:5:5, optimum proportion of m(IFRs):m(MgO/EG/SiO2) is 1:0.18. The influence of IFRs and MgO/EG/SiO2 on thermal stability and flame-retardant properties of polypropylene based wood-plastics composite (WPC) was evaluated by thermogravimetric analysis (TGA) and cone calorimetry analysis (CONE). The results show that adding IFRs and MgO/EG/SiO2 to WPC can improve its thermal stability effectively, and the char residue of WPC/IFRs/MgO/EG/SiO2 at 600℃ reaches to 22.42%. The peak heat release rate (PHRR), the total heat release (THR) and total smoke production release (TSP) of WPC/IFRs reduce by 19.0%, 8.7% and 22.1%, respectively, compared with WPC. MgO/EG/SiO2 can further improve the flame retardant efficiency of IFRs, and the PHRR and THR of WPC/IFRs/MgO/EG/SiO2 drop by 33.0% and 13.8%, respectively, compared with WPC.
2017, 34(2): 204-210
doi: 10.11944/j.issn.1000-0518.2017.02.160117
Abstract:
Preparation of crumb rubber modified asphalt (CRMA) is an effective way to recycle waste rubber and to reduce environmental pollution. To study the physical and chemical behavior of crumb rubber in asphalt, dibutylphthalate (DBP) is used to simulate the light components of asphalt. The reaction time is 1.5 h at 175℃ after crumb rubber is stirred into the DBP. The light components are separated from crumb rubber. The physical and chemical effects of crumb rubber in the light components are investigated by gas chromatography-mass spectrometry (GC-MS) analysis of the separated light component. To study functional group changes and thermodynamic properties of rubber modified asphalt, CRMAs were respectively prepared under conditions of different temperature and treating time. Infrared spectra (IR) and differential scanning calorimetry (DSC) tests were then conducted on asphalt samples after removing crumb rubber by sieving method. The results indicate that 19 kinds of substances are detected in separated light components. In addition to the highest contents of DBP, the others are speculated to be all the materials from crumb rubber or the products from the complex physical and chemical reactions between crumb rubber and the light components. The absorption peaks of typical functional groups -CH2 and C=C increase significantly, which fully proves that the molecular chains of rubber rupture and release small molecule materials dissolved into asphalt playing a role of asphalt modification. The strong endothermic peaks of DSC curve appear for asphalt samples prepared at 195℃, 1.5 h and 175℃, 3.0 h. Therefore, the processing conditions such as high temperature and long time may lead to excessive degradation or aggregation of crumb rubber as well as asphalt aging, which change the physical and chemical properties and performances of CRMA. The production conditions of CRMA are recommended that the dosage of crumb rubber is 20% approximately, at a temperature less than 195℃ and the treating time less than 1.5 h.
Preparation of crumb rubber modified asphalt (CRMA) is an effective way to recycle waste rubber and to reduce environmental pollution. To study the physical and chemical behavior of crumb rubber in asphalt, dibutylphthalate (DBP) is used to simulate the light components of asphalt. The reaction time is 1.5 h at 175℃ after crumb rubber is stirred into the DBP. The light components are separated from crumb rubber. The physical and chemical effects of crumb rubber in the light components are investigated by gas chromatography-mass spectrometry (GC-MS) analysis of the separated light component. To study functional group changes and thermodynamic properties of rubber modified asphalt, CRMAs were respectively prepared under conditions of different temperature and treating time. Infrared spectra (IR) and differential scanning calorimetry (DSC) tests were then conducted on asphalt samples after removing crumb rubber by sieving method. The results indicate that 19 kinds of substances are detected in separated light components. In addition to the highest contents of DBP, the others are speculated to be all the materials from crumb rubber or the products from the complex physical and chemical reactions between crumb rubber and the light components. The absorption peaks of typical functional groups -CH2 and C=C increase significantly, which fully proves that the molecular chains of rubber rupture and release small molecule materials dissolved into asphalt playing a role of asphalt modification. The strong endothermic peaks of DSC curve appear for asphalt samples prepared at 195℃, 1.5 h and 175℃, 3.0 h. Therefore, the processing conditions such as high temperature and long time may lead to excessive degradation or aggregation of crumb rubber as well as asphalt aging, which change the physical and chemical properties and performances of CRMA. The production conditions of CRMA are recommended that the dosage of crumb rubber is 20% approximately, at a temperature less than 195℃ and the treating time less than 1.5 h.
2017, 34(2): 211-219
doi: 10.11944/j.issn.1000-0518.2017.02.160176
Abstract:
Composite ceramsite was prepared by sintering solid waste residue of shield residues, powdered rice straw and magnesium oxide. The effects of pH, sorption time and temperature were investigated. The results show that the optimal sintering temperature of the composite ceramsite is 700℃ with the mass ratio of shield residue to powdered rice straw and to magnesium oxide as 7:2:1. The optimum adsorption pH is 6.3, and phosphate can reach adsorption equilibrium within 12 hours. The Lagergren pseudo second order kinetics and the Temkin isotherm model fit the experimental data well. The adsorption capacity increases with increasing the sorption temperature, and the maximum adsorption of ceramsite is 12.76 mg/g at 40℃. The adsorption is confirmed as a nonspontaneous endothermic process according to the results of ΔH=5.64 kJ/mol > 0, ΔS=8.00 J/(K·mol) > 0, ΔG=3.16 kJ/mol > 0. Meanwhile, the adsorbed phosphate on ceramsite can be recovered by using 2.0 mol/L NaOH.
Composite ceramsite was prepared by sintering solid waste residue of shield residues, powdered rice straw and magnesium oxide. The effects of pH, sorption time and temperature were investigated. The results show that the optimal sintering temperature of the composite ceramsite is 700℃ with the mass ratio of shield residue to powdered rice straw and to magnesium oxide as 7:2:1. The optimum adsorption pH is 6.3, and phosphate can reach adsorption equilibrium within 12 hours. The Lagergren pseudo second order kinetics and the Temkin isotherm model fit the experimental data well. The adsorption capacity increases with increasing the sorption temperature, and the maximum adsorption of ceramsite is 12.76 mg/g at 40℃. The adsorption is confirmed as a nonspontaneous endothermic process according to the results of ΔH=5.64 kJ/mol > 0, ΔS=8.00 J/(K·mol) > 0, ΔG=3.16 kJ/mol > 0. Meanwhile, the adsorbed phosphate on ceramsite can be recovered by using 2.0 mol/L NaOH.
2017, 34(2): 220-224
doi: 10.11944/j.issn.1000-0518.2017.02.160161
Abstract:
ZnO with various morphologies has been obtained by microwave hydrothermal method with the assistance of ethylene glycol (EG). By adjusting the concentration of EG in the system, the morphology of sample can be tuned from irregular disks to twin crystal rods, to shuttle shape, and finally to sphere shape. It is founded that the concentration of EG plays an important role in adjusting system pressure, which significantly influence the reaction speed and final shape of products. The photocatalytic activity of as-prepared ZnO with different morphologies in aqueous solution was investigated by bleaching dye rhodamine B under Xe lamp. The sphere shape sample possesses the most efficient photocatalytic properties, which can completely photodegradate rhodamine B in 50 min.
ZnO with various morphologies has been obtained by microwave hydrothermal method with the assistance of ethylene glycol (EG). By adjusting the concentration of EG in the system, the morphology of sample can be tuned from irregular disks to twin crystal rods, to shuttle shape, and finally to sphere shape. It is founded that the concentration of EG plays an important role in adjusting system pressure, which significantly influence the reaction speed and final shape of products. The photocatalytic activity of as-prepared ZnO with different morphologies in aqueous solution was investigated by bleaching dye rhodamine B under Xe lamp. The sphere shape sample possesses the most efficient photocatalytic properties, which can completely photodegradate rhodamine B in 50 min.
2017, 34(2): 225-232
doi: 10.11944/j.issn.1000-0518.2017.02.160138
Abstract:
A nano-sized microwave absorbing Fe3O4/multi-walled carbon nanotubes (MWNTs) hybrids with dielectric and magnetic properties was fabricated by solvothermal method. The morphology and structure of Fe3O4/MWNTs hybrids were characterized by X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR), thermal gravimetric analysis (TGA) and transmission electron-microscopy (TEM). The results show that Fe3O4/MWNTs hybrids can be dispersed homogeneously, and Fe3O4 particles exhibit crystal integrity. The electromagnetic parameters of Fe3O4/MWNTs hybrids were measured by vector network instrument. The microwave absorbing properties shows that the microwave absorption frequency of Fe3O4/MWNTs hybrids shifts to low frequency with the increase of thickness. The maximum reflection loss (RL) of Fe3O4/MWNTs hybrids is -42.9 dB at 6.16 GHz and 3.2 nm thickness, and the frequency bandwidth is 1.42 GHz for -10 dB RL over.
A nano-sized microwave absorbing Fe3O4/multi-walled carbon nanotubes (MWNTs) hybrids with dielectric and magnetic properties was fabricated by solvothermal method. The morphology and structure of Fe3O4/MWNTs hybrids were characterized by X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR), thermal gravimetric analysis (TGA) and transmission electron-microscopy (TEM). The results show that Fe3O4/MWNTs hybrids can be dispersed homogeneously, and Fe3O4 particles exhibit crystal integrity. The electromagnetic parameters of Fe3O4/MWNTs hybrids were measured by vector network instrument. The microwave absorbing properties shows that the microwave absorption frequency of Fe3O4/MWNTs hybrids shifts to low frequency with the increase of thickness. The maximum reflection loss (RL) of Fe3O4/MWNTs hybrids is -42.9 dB at 6.16 GHz and 3.2 nm thickness, and the frequency bandwidth is 1.42 GHz for -10 dB RL over.
2017, 34(2): 233-241
doi: 10.11944/j.issn.1000-0518.2017.02.160125
Abstract:
To improve the electrochromic performance of thin film[PEI/P5W30]30(PEI:polyethyleneimine), graphene oxide with large two-dimensional size and excellent electrical conductivity was incorporated. We have fabricated an organic/inorganic hybrid thin film[PEI/P5W30/PEI/GO]30 based on Preyssler-type polyoxometalate K12.5Na1.5[NaP5W30O110]·15H2O (P5W30) and graphene oxide (GO) by layer-by-layer method (LBL). The composition and growth process of the film were characterized by ultraviolet-visible (UV-Vis) spectrophotometer. We investigated the morphology by atomic force microscopy (AFM) and studied the electrochemical properties by cyclic voltammetry of the multilayers. The film displays reversible electrochromic behavior from colorless to blue when applied a redox potential, and the response time of the coloring and discoloring process are all within 10 seconds. More importantly, the electrochromic property has no obvious change after 150 cycles under double potential step at 0.75 V and -0.75 V, the electrocromic film reflects a good reversibility. The film of[PEI/P5W30/PEI/GO]30 exhibits fast response, long durability after GO embedding, and has a potential application in electrochromic devices.
To improve the electrochromic performance of thin film[PEI/P5W30]30(PEI:polyethyleneimine), graphene oxide with large two-dimensional size and excellent electrical conductivity was incorporated. We have fabricated an organic/inorganic hybrid thin film[PEI/P5W30/PEI/GO]30 based on Preyssler-type polyoxometalate K12.5Na1.5[NaP5W30O110]·15H2O (P5W30) and graphene oxide (GO) by layer-by-layer method (LBL). The composition and growth process of the film were characterized by ultraviolet-visible (UV-Vis) spectrophotometer. We investigated the morphology by atomic force microscopy (AFM) and studied the electrochemical properties by cyclic voltammetry of the multilayers. The film displays reversible electrochromic behavior from colorless to blue when applied a redox potential, and the response time of the coloring and discoloring process are all within 10 seconds. More importantly, the electrochromic property has no obvious change after 150 cycles under double potential step at 0.75 V and -0.75 V, the electrocromic film reflects a good reversibility. The film of[PEI/P5W30/PEI/GO]30 exhibits fast response, long durability after GO embedding, and has a potential application in electrochromic devices.
2017, 34(2): 242-244
doi: 10.11944/j.issn.1000-0518.2017.02.160251
Abstract:
By using Pd/Pt as main active ingredients and Fe/Ni as auxiliary, coconut shell activated carbon (ACcs) loaded mono metal (M/ACcs), binary metal (M-Ni/ACcs, M-Fe/ACcs) and ternary metal (M-Ni-Fe/ACcs) catalysts have been prepared via metal impregnation and H2 reduction. The catalytic activity and selectivity of the catalysts for conversion of CCl4 to CHCl3 by liquid-phase hydrogenation was evaluated. Compared with Pt-based catalysts, the Pd-based counterparts have higher activity, but lower CHCl3 selectivity. During initial reaction time of 5 h, the catalytic activity order follows:Pd-Ni-Fe/ACcs > Pd-Fe/ACcs > Pd/ACcs > Pd-Ni/ACcs and Pt/ACcs≈Pt-Fe/ACcs > Pt-Ni/ACcs > Pt-Ni-Fe/ACcs. Addition of Fe component improves the activity while single addition of Ni lowers the catalytic performance. The Pd-Ni-Fe/ACcs catalyst can realize more than 97% conversion of CCl4 and nearly 100% selectivity for CHCl3 at 393 K for 5 h.
By using Pd/Pt as main active ingredients and Fe/Ni as auxiliary, coconut shell activated carbon (ACcs) loaded mono metal (M/ACcs), binary metal (M-Ni/ACcs, M-Fe/ACcs) and ternary metal (M-Ni-Fe/ACcs) catalysts have been prepared via metal impregnation and H2 reduction. The catalytic activity and selectivity of the catalysts for conversion of CCl4 to CHCl3 by liquid-phase hydrogenation was evaluated. Compared with Pt-based catalysts, the Pd-based counterparts have higher activity, but lower CHCl3 selectivity. During initial reaction time of 5 h, the catalytic activity order follows:Pd-Ni-Fe/ACcs > Pd-Fe/ACcs > Pd/ACcs > Pd-Ni/ACcs and Pt/ACcs≈Pt-Fe/ACcs > Pt-Ni/ACcs > Pt-Ni-Fe/ACcs. Addition of Fe component improves the activity while single addition of Ni lowers the catalytic performance. The Pd-Ni-Fe/ACcs catalyst can realize more than 97% conversion of CCl4 and nearly 100% selectivity for CHCl3 at 393 K for 5 h.
