A Titanium tetrachloride-1-methyl-3-ethytimidazolium chloride melt has been prepared.The reduction process of Ti(IV)appears to be diffusion controlled in the composition of 0.4:1 mole ralio of TiCl_4-1-methyl-3-ethyli...A Titanium tetrachloride-1-methyl-3-ethytimidazolium chloride melt has been prepared.The reduction process of Ti(IV)appears to be diffusion controlled in the composition of 0.4:1 mole ralio of TiCl_4-1-methyl-3-ethylimidazolium chloride and the electrochemical behavior of Ti(IV)shows remarkable compositon dependence.展开更多
The catalysis technology of propylene dimerization to form 4-methyl-1-pentene(4MP1)using a Cu-K/K_(2)CO_(3) solid base catalyst is a well-known heterogeneous catalytic reaction.In this study,the intrinsic kinetics of ...The catalysis technology of propylene dimerization to form 4-methyl-1-pentene(4MP1)using a Cu-K/K_(2)CO_(3) solid base catalyst is a well-known heterogeneous catalytic reaction.In this study,the intrinsic kinetics of propylene dimerization were studied in a fixed-bed continuous reactor.Internal and external diffusion during the dimerization reaction experiments were eliminated by adjusting the flow rate of the carrier gas and the particle size of the catalyst support.Then,the concentration changes of each substance at the outlet of the catalyst bed under different residence times were investigated.Moreover,the suitable reaction kinetics equations was derived using the Langmuir Hinshelwood-Hougen-Watson kinetic model.Finally,the activation energy for each reaction involved in the dimerization reaction was calculated.The activation energies of 4MP1,branched by-products,and 1-hexene were 115.0,150.8,and 177.4 kJ/mol,respectively.The effect of process conditions on propylene dimerization with solid base catalysts was studied through kinetic model simulation.By comparing the theoretical values obtained from the simulation with the experimental results,the applicability and accuracy of the kinetic model were verified.展开更多
We analysed the photooxidation reaction in the electro-(1O2) and nucleophilic (O2•−) reaction of 2-pyridone azo derivatives. First, we calculated the energy (enthalpies) of tautomers formation, which is a measure of d...We analysed the photooxidation reaction in the electro-(1O2) and nucleophilic (O2•−) reaction of 2-pyridone azo derivatives. First, we calculated the energy (enthalpies) of tautomers formation, which is a measure of durability and the probability of their formation. We performed the light fastness calculations of the monoazopyridone dyes. Using the semi-empirical methods of quantum chemistry AM1 and PM3, the reactivity indicators of superdelocalisability (SrE(N)) and the electron density distribution in ground state on the highest occupied HOMO orbital and the lowest unoccupied excited state LUMO in 2-pyridone phenylazo derivatives were calculated. Superdelocalisability coefficients enable the stability to oxidising agents of various chemical molecules depending on the tautomeric forms in which they may occur. The results of the electron density calculations at the HOMO and LUMO boundary orbitals allow to determine the tendency to electrophilic attack with singlet oxygen 1O2 or nucleophilic attack of the superoxide anion O2•−on a specific atom in the molecule. The structure of the dyes was optimised with MM+, MD and AM1 or PM3 until a constant energy value was achieved with a convergence criterion of 0.01 kcal/mol.展开更多
目的探讨血清几丁质酶-3样蛋白1(chitinase 3-like protein 1,CHI3L1)与血液透析患者全因死亡和心脑血管疾病死亡之间的关系。方法本研究为前瞻性队列研究,病例来自2014年9月北京大学第三医院肾内科维持性血液透析患者。测定基线血CHI3L...目的探讨血清几丁质酶-3样蛋白1(chitinase 3-like protein 1,CHI3L1)与血液透析患者全因死亡和心脑血管疾病死亡之间的关系。方法本研究为前瞻性队列研究,病例来自2014年9月北京大学第三医院肾内科维持性血液透析患者。测定基线血CHI3L1水平,并根据中位数将患者分为高CHI3L1组和低CHI3L1组,随访9年。用Kaplan-Meier生存分析高CHI3L1组和低CHI3L1组患者生存率的差异,用限制性立方样条(restricted cubic spline,RCS)曲线描述CHI3L1与全因死亡率的剂量反应关系,用多因素COX比例风险模型分析患者全因死亡或心脑血管疾病死亡的独立危险因素。结果共纳入109例患者,随访时间为80.0(38.2,113.2)个月。Kaplan-Meier生存分析显示高CHI3L1组患者全因死亡率高于低CHI3L1组(χ^(2)=4.720,P=0.030),2组患者心脑血管疾病死亡率无明显差异(χ^(2)=1.954,P=0.162)。当CHI3L1≥199.8 ng/ml时,全因死亡率随着CHI3L1水平的增加有明显增加(HR=1.747,95%CI:1.035~2.947,P=0.037)。COX回归分析结果显示:年龄增加(HR=1.029,95%CI:1.001~1.056,P=0.040)、长透析龄(HR=2.251,95%CI:1.310~3.868,P=0.003)、收缩压高(HR=1.022,95%CI:1.008~1.036,P=0.002)、血肌酐低(HR=0.135,95%CI:0.064~0.283,P<0.001)均为血液透析患者全因死亡的独立危险因素,多种因素校正后高CHI3L1仍然是患者全因死亡的独立危险因素(HR=1.963,95%CI:1.010~3.813,P=0.047)。结论高CHI3L1组患者全因死亡率高于低CHI3L1组患者,血CHI3L1可能是血液透析患者全因死亡的独立预测指标。展开更多
文摘A Titanium tetrachloride-1-methyl-3-ethytimidazolium chloride melt has been prepared.The reduction process of Ti(IV)appears to be diffusion controlled in the composition of 0.4:1 mole ralio of TiCl_4-1-methyl-3-ethylimidazolium chloride and the electrochemical behavior of Ti(IV)shows remarkable compositon dependence.
基金supported by the National Natural Science Foundation of China under agreement number 22378026the Project of Construction of Innovative Teams and Teacher Career Development for Universities and Colleges under Beijing Municipality(IDHT20180508).
文摘The catalysis technology of propylene dimerization to form 4-methyl-1-pentene(4MP1)using a Cu-K/K_(2)CO_(3) solid base catalyst is a well-known heterogeneous catalytic reaction.In this study,the intrinsic kinetics of propylene dimerization were studied in a fixed-bed continuous reactor.Internal and external diffusion during the dimerization reaction experiments were eliminated by adjusting the flow rate of the carrier gas and the particle size of the catalyst support.Then,the concentration changes of each substance at the outlet of the catalyst bed under different residence times were investigated.Moreover,the suitable reaction kinetics equations was derived using the Langmuir Hinshelwood-Hougen-Watson kinetic model.Finally,the activation energy for each reaction involved in the dimerization reaction was calculated.The activation energies of 4MP1,branched by-products,and 1-hexene were 115.0,150.8,and 177.4 kJ/mol,respectively.The effect of process conditions on propylene dimerization with solid base catalysts was studied through kinetic model simulation.By comparing the theoretical values obtained from the simulation with the experimental results,the applicability and accuracy of the kinetic model were verified.
文摘We analysed the photooxidation reaction in the electro-(1O2) and nucleophilic (O2•−) reaction of 2-pyridone azo derivatives. First, we calculated the energy (enthalpies) of tautomers formation, which is a measure of durability and the probability of their formation. We performed the light fastness calculations of the monoazopyridone dyes. Using the semi-empirical methods of quantum chemistry AM1 and PM3, the reactivity indicators of superdelocalisability (SrE(N)) and the electron density distribution in ground state on the highest occupied HOMO orbital and the lowest unoccupied excited state LUMO in 2-pyridone phenylazo derivatives were calculated. Superdelocalisability coefficients enable the stability to oxidising agents of various chemical molecules depending on the tautomeric forms in which they may occur. The results of the electron density calculations at the HOMO and LUMO boundary orbitals allow to determine the tendency to electrophilic attack with singlet oxygen 1O2 or nucleophilic attack of the superoxide anion O2•−on a specific atom in the molecule. The structure of the dyes was optimised with MM+, MD and AM1 or PM3 until a constant energy value was achieved with a convergence criterion of 0.01 kcal/mol.
