The reaction of cyclohexene oxide with CO2 to synthesize cyclohexene carbonate, catalyzed by a complex catalyst, under 1.4—2.6 MPa of pressure, at 130—170℃ of temperature was studied experimentally.After eliminatin...The reaction of cyclohexene oxide with CO2 to synthesize cyclohexene carbonate, catalyzed by a complex catalyst, under 1.4—2.6 MPa of pressure, at 130—170℃ of temperature was studied experimentally.After eliminating the influence of external diffusion, the rate constants of positive and reverse reactions were estimated by fitting the experimental data to a macro-kinetics model.The results indicated that the reaction was an exothermal reaction.The reaction heat was -42.11 kJ·mol-1.The activation energy was 27.51 kJ·mol-1 for the positive reaction, and 69.66 kJ·mol-1 for the reverse reaction.展开更多
According to the theoretical bases of thermokinetics and analog thermogram method, a general analog thermogram method for several types of reversible reactions, with which the rate constants of forward and backward re...According to the theoretical bases of thermokinetics and analog thermogram method, a general analog thermogram method for several types of reversible reactions, with which the rate constants of forward and backward reactions and equilibrium constant can be calculted from the same thermogram simultaneously, has been proposed in this paper. The thermokinetics of the reactions of nitroethane with ammonia at 15℃ and 25℃ and with tris (hydroxymethyl)aminomethane at 15℃ and 30℃ have been studied with this method,re-spectively. The results of rate constants and equilibrium constants calculated with this method are in agreement with those in literatures. Therefore, the analog thermogram method for the reversible reactions is believed to be correct.展开更多
文摘The reaction of cyclohexene oxide with CO2 to synthesize cyclohexene carbonate, catalyzed by a complex catalyst, under 1.4—2.6 MPa of pressure, at 130—170℃ of temperature was studied experimentally.After eliminating the influence of external diffusion, the rate constants of positive and reverse reactions were estimated by fitting the experimental data to a macro-kinetics model.The results indicated that the reaction was an exothermal reaction.The reaction heat was -42.11 kJ·mol-1.The activation energy was 27.51 kJ·mol-1 for the positive reaction, and 69.66 kJ·mol-1 for the reverse reaction.
文摘为了快速、简便地评价冬凌草(Isodon rubescens(Hemsley)H.Hara)活性成分的抗肿瘤活性,以冬凌草活性成分冬凌草甲素和冬凌草乙素及其乙酰化产物与对硝基苯甲酰乙酸乙酯(ENBA)进行迈克尔加成反应,以反应动力学得出迈克尔加成反应的反应活性,首次以反应活性预测了对冬凌草甲素(1)、冬凌草乙素(2)、1,14-二乙酰基冬凌草甲素(1a)和1,6-二乙酰基冬凌草乙素(2a)4个对映-贝壳杉烯的抗肿瘤活性。结果表明:4种活性成分的迈克尔加成反应均符合二级动力学方程,反应活性1>1a>2>2a,根据阿伦尼乌斯公式,测得冬凌草甲素活化能(Ea)为(38.7±5.8)kJ/mol,冬凌草乙素Ea为(46.8±7.1)kJ/mol。采用~1H NMR和^(13) C NMR等波谱技术鉴定冬凌草甲素与ENBA经迈克尔加成反应得到的新化合物为1α,6β,7β,14β-四羟基-7α,20-环氧-17-(2-(3-(4-硝基苯基))-3-氧-丙酸乙酯)-对映贝壳杉烷-15-酮,命名为nitrobenoridonin(1b)。4个对映-贝壳杉烯具有较强的体外抗肿瘤活性,经测定它们的抗肿瘤活性大小依次为1>1a>2>2a,与其迈克尔加成反应活性排序一致,表明迈克尔加成反应活性与抗肿瘤活性之间存在较好的相关性,可以通过测定迈克尔加成反应活性预测对映-贝壳杉烯的抗肿瘤活性。
文摘According to the theoretical bases of thermokinetics and analog thermogram method, a general analog thermogram method for several types of reversible reactions, with which the rate constants of forward and backward reactions and equilibrium constant can be calculted from the same thermogram simultaneously, has been proposed in this paper. The thermokinetics of the reactions of nitroethane with ammonia at 15℃ and 25℃ and with tris (hydroxymethyl)aminomethane at 15℃ and 30℃ have been studied with this method,re-spectively. The results of rate constants and equilibrium constants calculated with this method are in agreement with those in literatures. Therefore, the analog thermogram method for the reversible reactions is believed to be correct.
