选择甲酰胺作磁性Fe3O4微晶的分散剂，通过设计反相悬浮聚合体系，合成了粒径分布窄、球状亲水性含环氧基磁性聚合物（MGM）．利用扫描电子显微镜（SEM）、红外光谱（FT-IR）、X射线粉末衍射仪（XRD）、振动样品磁强计（VSM）和低温N2...选择甲酰胺作磁性Fe3O4微晶的分散剂，通过设计反相悬浮聚合体系，合成了粒径分布窄、球状亲水性含环氧基磁性聚合物（MGM）．利用扫描电子显微镜（SEM）、红外光谱（FT-IR）、X射线粉末衍射仪（XRD）、振动样品磁强计（VSM）和低温N2吸附以及化学分析方法对聚合物进行了性能表征．结果表明，合成的MGM呈球形，且粒度分布较窄，粒径为0．13，0．28mm的粒子占91％；甲酰胺分散Fe3O4，微晶表面的亲水性进一步增强，单体甲基丙烯酸缩水甘油酯和N，N＇-亚甲基双丙烯酰胺交联共聚生成的胶粒能够包埋Fe3O4微晶形成胶核，胶核聚集形成均匀、稳定的MGM微球．MGM中Fe3O4含量为6．17％时，比饱和磁化强度σ．达6．5emu／g；其比表面积、平均孔径和孔容分别为117．6m^2／g，15．6nm和0．46cm^3/g，表面环氧基团含量为0．53mmol／g．MGM借助自身的活性环氧基团在十分温和的条件下共价偶联青霉素酰化酶（penicillin G acylase EC 3．5．1．11，简称PGA），制备的固定化酶在37℃下催化水解青霉素G钾生成6-氨基青霉烷酸（6-APA）的表观活性达502IU／g，并且在使用过程中投有出现磁聚集现象．展开更多
The epoxidation of unsaturated fatty acid methyl esters(FAMEs)by peroxyacetic acid generated in situ from hydrogen peroxide and acetic acid was studied in the presence of SO3H-functional Brnsted acidic ionic liquid (I...The epoxidation of unsaturated fatty acid methyl esters(FAMEs)by peroxyacetic acid generated in situ from hydrogen peroxide and acetic acid was studied in the presence of SO3H-functional Brnsted acidic ionic liquid (IL)[C3SO3HMIM][HSO4]as catalyst.The effects of hydrogen peroxide/ethylenic unsaturation ratio,acetic acid concentration,IL concentration,recycling of the IL catalyst,and temperature on the conversion to oxirane were studied.The kinetics and thermodynamics of unsaturated FAMEs epoxidation and the kinetics of oxirane cleavage of the epoxidized FAMEs by acetic acid were also studied.The conversion of ethylenic unsaturation group to oxirane, the reaction rate of the conversion to oxirane,and the rate of hydrolysis(oxirane cleavage)were higher by using the IL catalyst.展开更多
A series of substituted l,4-oxathiane-3-thione derivatives were synthesized via one-pot multicomponent reactions of nitromethane,carbon disulfide and oxiranes in the presence of Et;N in water as the solvent under micr...A series of substituted l,4-oxathiane-3-thione derivatives were synthesized via one-pot multicomponent reactions of nitromethane,carbon disulfide and oxiranes in the presence of Et;N in water as the solvent under microwave irradiation.Particularly valuable features of this method include high yields of products,broad substrate scope,short reaction time and straightforward procedure.展开更多
目的:建立顶空气相色谱法测定药用辅料15-羟基硬脂酸聚乙二醇酯中的残留杂质环氧乙烷和二氧六环的含量。为15-羟基硬脂酸聚乙二醇酯的质量控制提供参考和依据。方法:参考国内外药典方法,选用色谱柱DB-5(15 m×0.32 mm, 1μm),以5%苯...目的:建立顶空气相色谱法测定药用辅料15-羟基硬脂酸聚乙二醇酯中的残留杂质环氧乙烷和二氧六环的含量。为15-羟基硬脂酸聚乙二醇酯的质量控制提供参考和依据。方法:参考国内外药典方法,选用色谱柱DB-5(15 m×0.32 mm, 1μm),以5%苯基-95%甲基聚硅氧烷为固定液,采用程序升温模式:起始温度为35℃,维持5 min,以每分钟5℃的速率升温至180℃,然后以每分钟30℃的速率升温至250℃,维持5 min。进样口温度为150℃,检测器温度为250℃,顶空平衡温度70℃,平衡时间45 min,分流比为10∶1。按标准加入法计算供试品中环氧乙烷和二氧六环的含量。结果:在该色谱条件下,环氧乙烷和二氧六环分别在0.5~4μg·mL^(-1)和5~40μg·mL^(-1)范围内线性关系良好(r≥0.99);平均回收率均为75%(RSD=5%,n=9)。来自三个厂家的五批次样品均未检测出环氧乙烷,其中一批样品未检出二氧六环,另外四批样品中二氧六环含量均小于0.005%,符合限度要求。结论:该方法适用于15-羟基硬脂酸聚乙二醇酯中环氧乙烷和二氧六环含量测定,为15-羟基硬脂酸聚乙二醇酯的质量控制提供了参考与指导。展开更多
The aim of this research work was to evaluate the potential of using renewable natural feedstock,i.e.,Jatropha curcas oil(JCO)for the synthesis of non-isocyanate polyurethane(NIPU)resin for wood composite applications...The aim of this research work was to evaluate the potential of using renewable natural feedstock,i.e.,Jatropha curcas oil(JCO)for the synthesis of non-isocyanate polyurethane(NIPU)resin for wood composite applications.Commercial polyurethane(PU)is synthesized through a polycondensation reaction between isocyanate and poly-ol.However,utilizing toxic and unsustainable isocyanates for obtaining PU could contribute to negative impacts on the environment and human health.Therefore,the development of PU from eco-friendly and sustainable resources without the isocyanate route is required.In this work,tetra-n-butyl ammonium bromide was used as the activator to open the epoxy ring with 3-Aminopropyltriethoxisylane as a catalyst to yield urethane of JCO(UJCO).The UJCO were characterized by Fourier Transform Infra-Red spectroscopy(FTIR)and their oxirane,and hydroxyl values were measured.The result showed that a decrease in oxirane value was found while the hydroxyl value was increased during the time,confirming that the urethane group was formed.The presence of functional groups in FTIR spectra at wave numbers 1732.08,1562.34,and 3348.42 cm^(−1) indicates the functional groups of C=O(urethane carbonyl),–NH,and–OH,respectively confirmed this finding.The potential applications of NIPU in the wood composite were also outlined.展开更多
The structures, energies, atomic chaiges and IR spectra of complexes (CH2)2O…XY (X, Y = H, F, Cl, Br, and I) have been examined by means of ab initio molecular orbital theory at the second-order level of Moller-Ples... The structures, energies, atomic chaiges and IR spectra of complexes (CH2)2O…XY (X, Y = H, F, Cl, Br, and I) have been examined by means of ab initio molecular orbital theory at the second-order level of Moller-Plesset perturbation correction. It is found that the hydrogen bond O…H-X is non-linear. The attraction between X and the H atoms in oxirane ring causes O…H-X bond bending. The hydrogen bond slighdy weakens the bond strength of C-O, and leads the bending and stretching mode of IR to shift to the red. The calculation results show that there is no evidence of a significant extent of proton transfer to give (CH2)2OH+ …X- in the isolated complexes.展开更多
The reaction of singlet oxygen with ethylene has been studied at the ab initio level with both HF/3-21G and HF/6-31G basis sets, fully optimizing the geometries of the critical points. The transition state leading to... The reaction of singlet oxygen with ethylene has been studied at the ab initio level with both HF/3-21G and HF/6-31G basis sets, fully optimizing the geometries of the critical points. The transition state leading to the intermediate peroxirane from the initial reactants is found,Iocated at 81.71 kJ/mol above the dissociation limit. The vibrational analysis is done with two basis sets. From the results it can be seen that the frequencies have not been made an improvement obviously with augmented 6-31G compared to 3-21G basis; it follows that main reason for too high HF/3-21G frequency could mainly be the vibrational anharmonicity. The eigenvector corresponding to the single imaginary vibrational frequency is dominated by the larger O-O distance. The finding of the transition state confirms that the peroxirane minimum can be reachable passing through a peroxirane-like saddle point. In addition , the mechanisms of the reaction forming oxirane are discussed as well.展开更多
文摘选择甲酰胺作磁性Fe3O4微晶的分散剂，通过设计反相悬浮聚合体系，合成了粒径分布窄、球状亲水性含环氧基磁性聚合物（MGM）．利用扫描电子显微镜（SEM）、红外光谱（FT-IR）、X射线粉末衍射仪（XRD）、振动样品磁强计（VSM）和低温N2吸附以及化学分析方法对聚合物进行了性能表征．结果表明，合成的MGM呈球形，且粒度分布较窄，粒径为0．13，0．28mm的粒子占91％；甲酰胺分散Fe3O4，微晶表面的亲水性进一步增强，单体甲基丙烯酸缩水甘油酯和N，N＇-亚甲基双丙烯酰胺交联共聚生成的胶粒能够包埋Fe3O4微晶形成胶核，胶核聚集形成均匀、稳定的MGM微球．MGM中Fe3O4含量为6．17％时，比饱和磁化强度σ．达6．5emu／g；其比表面积、平均孔径和孔容分别为117．6m^2／g，15．6nm和0．46cm^3/g，表面环氧基团含量为0．53mmol／g．MGM借助自身的活性环氧基团在十分温和的条件下共价偶联青霉素酰化酶（penicillin G acylase EC 3．5．1．11，简称PGA），制备的固定化酶在37℃下催化水解青霉素G钾生成6-氨基青霉烷酸（6-APA）的表观活性达502IU／g，并且在使用过程中投有出现磁聚集现象．
文摘The epoxidation of unsaturated fatty acid methyl esters(FAMEs)by peroxyacetic acid generated in situ from hydrogen peroxide and acetic acid was studied in the presence of SO3H-functional Brnsted acidic ionic liquid (IL)[C3SO3HMIM][HSO4]as catalyst.The effects of hydrogen peroxide/ethylenic unsaturation ratio,acetic acid concentration,IL concentration,recycling of the IL catalyst,and temperature on the conversion to oxirane were studied.The kinetics and thermodynamics of unsaturated FAMEs epoxidation and the kinetics of oxirane cleavage of the epoxidized FAMEs by acetic acid were also studied.The conversion of ethylenic unsaturation group to oxirane, the reaction rate of the conversion to oxirane,and the rate of hydrolysis(oxirane cleavage)were higher by using the IL catalyst.
文摘A series of substituted l,4-oxathiane-3-thione derivatives were synthesized via one-pot multicomponent reactions of nitromethane,carbon disulfide and oxiranes in the presence of Et;N in water as the solvent under microwave irradiation.Particularly valuable features of this method include high yields of products,broad substrate scope,short reaction time and straightforward procedure.
文摘The aim of this research work was to evaluate the potential of using renewable natural feedstock,i.e.,Jatropha curcas oil(JCO)for the synthesis of non-isocyanate polyurethane(NIPU)resin for wood composite applications.Commercial polyurethane(PU)is synthesized through a polycondensation reaction between isocyanate and poly-ol.However,utilizing toxic and unsustainable isocyanates for obtaining PU could contribute to negative impacts on the environment and human health.Therefore,the development of PU from eco-friendly and sustainable resources without the isocyanate route is required.In this work,tetra-n-butyl ammonium bromide was used as the activator to open the epoxy ring with 3-Aminopropyltriethoxisylane as a catalyst to yield urethane of JCO(UJCO).The UJCO were characterized by Fourier Transform Infra-Red spectroscopy(FTIR)and their oxirane,and hydroxyl values were measured.The result showed that a decrease in oxirane value was found while the hydroxyl value was increased during the time,confirming that the urethane group was formed.The presence of functional groups in FTIR spectra at wave numbers 1732.08,1562.34,and 3348.42 cm^(−1) indicates the functional groups of C=O(urethane carbonyl),–NH,and–OH,respectively confirmed this finding.The potential applications of NIPU in the wood composite were also outlined.
基金Project supported jointly by the National Natural Science Foundation of Chinathe Foundation of State Key Laboratory of Structural Chemistry
文摘 The structures, energies, atomic chaiges and IR spectra of complexes (CH2)2O…XY (X, Y = H, F, Cl, Br, and I) have been examined by means of ab initio molecular orbital theory at the second-order level of Moller-Plesset perturbation correction. It is found that the hydrogen bond O…H-X is non-linear. The attraction between X and the H atoms in oxirane ring causes O…H-X bond bending. The hydrogen bond slighdy weakens the bond strength of C-O, and leads the bending and stretching mode of IR to shift to the red. The calculation results show that there is no evidence of a significant extent of proton transfer to give (CH2)2OH+ …X- in the isolated complexes.
文摘 The reaction of singlet oxygen with ethylene has been studied at the ab initio level with both HF/3-21G and HF/6-31G basis sets, fully optimizing the geometries of the critical points. The transition state leading to the intermediate peroxirane from the initial reactants is found,Iocated at 81.71 kJ/mol above the dissociation limit. The vibrational analysis is done with two basis sets. From the results it can be seen that the frequencies have not been made an improvement obviously with augmented 6-31G compared to 3-21G basis; it follows that main reason for too high HF/3-21G frequency could mainly be the vibrational anharmonicity. The eigenvector corresponding to the single imaginary vibrational frequency is dominated by the larger O-O distance. The finding of the transition state confirms that the peroxirane minimum can be reachable passing through a peroxirane-like saddle point. In addition , the mechanisms of the reaction forming oxirane are discussed as well.
