漆树漆酶的催化氧化作用(ⅩⅠⅠⅠ)-Fe2+离子对漆酶催化氧化反应的影响

以5,6-二溴-2,3-二氰基氢醌为底物,在pH4.50条件下,用分光光度法考察了FeSO4对漆树漆酶催化氧化反应的影响.结果表明,在本文实验条件下SO2-4离子对酶促反应的影响基本可以忽略,而Fe2+离子对漆酶的催化氧化反应则有明显的竞争性抑制作用.研究证实,Fe2+离子的抑制作用是通过它还原酶促反应的产物半醌自由基阴离子来实现的.     

酶催化脂肪族聚酯的合成

脂肪族聚酯是一种可生物降解的新型高聚物,可通过化学催化、发酵和酶催化来合成.酶催化合成聚酯是一种新型的环境友好绿色化学技术,可以在温和条件下高效的合成聚酯,有着传统聚合方法难以比拟的优势.尤其是特种酶的应用,为传统方法难以合成的聚酯,开辟了一条新的合成途径.本文综述了脂肪酶催化缩聚、酯交换、内酯开环聚合等聚酯合成方法,并讨论了反应参数(如溶剂、温度、酶和单体的浓度)对反应的影响.     

酶促水解法拆分布洛芬乙酯的工艺研究

以布洛芬乙酯为反应底物,探索了酶促水解法拆分布洛芬的工艺。以曲拉通X-100为表面活性剂,利用南极假丝酵母脂肪酶B（CAL-B）催化拆分外消旋布洛芬乙酯,并对表面活性剂含量、有机溶剂种类和添加量、酶量、缓冲溶液pH、温度及时间等反应条件进行了优化;得到的最佳反应条件为：在pH为9.0的缓冲溶液中,添加80 mg曲拉通X-100、50 μL二氯甲烷和15 mg CAL-B,于30℃下反应48 h;在该条件下,S-布洛芬乙酯的剩余率（C）为65%,布洛芬乙酯的对映体过量值（ees）为94%。     

漆树漆酶的催化氧化作用(X)──叔丁基儿茶酚类底物的漆酶催化氧化和漆酶的微环境效应

对6个含叔丁基的儿茶酚类底物的离解和漆酶催化氧化反应进行了考察。结果表明:叔丁基的存在,有利于增进对底物的结合,并可以利用漆酶活性中心周围提供的pH环境和质子载体性质,促进底物的离解,使这类底物能在远低于其一级离解的弱酸性环境中进行反应。由于叔丁基的特性和漆酶的微环境效应的共同作用,这些底物在pH=6.0的水溶液环境中都能顺利地氧化成相应邻醌,并具有合成价值。ESR结果证明:这些底物在弱酸性条件下的漆酶催化反应经历了质子转移和单电子氧化步骤。     

酶促水解法拆分布洛芬乙酯的工艺研究

以布洛芬乙酯为反应底物,探索了酶促水解法拆分布洛芬的工艺.以曲拉通X-100为表面活性剂,利用南极假丝酵母脂肪酶B(CAL-B)催化拆分外消旋布洛芬乙酯,并对表面活性剂含量、有机溶剂种类和添加量、酶量、缓冲溶液pH、温度及时间等反应条件进行了优化,得到的最佳反应条件为:在pH为9.0的缓冲溶液中,添加80 mg曲拉通X-100、 50μL二氯甲烷和15 mg CAL-B,于30℃下反应48 h,在该条件下,S-布洛芬乙酯的剩余率(C)为65%,布洛芬乙酯的对映体过量值(ee_s)为94%.     

十二烷基苯磺酸/异辛烷微乳液中脂肪酶催化合成异丁酸异戊酯

在十二烷基苯磺酸(DBSA)/异辛烷微乳液中进行了脂肪酶催化合成异丁酸异戊酯的反应, 考察了微乳体系的含水量w₀、溶解酶缓冲溶液的pH值、反应温度等因素对酯合成反应转化率的影响; 与前期研究的CTAB微乳体系进行比较发现, DBSA微乳体系中的酯合成反应速率明显增加, 短时间内的转化率显著提高, 在温和条件下反应9 h后, 转化率达90%以上; 通过DBSA体系中有酶与无酶条件下反应进程的比较得知, DBSA作为一种质子酸对酯合成反应具有一定的催化能力; 提出了该体系中微乳催化、酶催化和质子酸催化的三重催化机理.     

微量热法研究漆酶和3,4,5-三羟基苯甲酸的反应

用LKB－2107型微量热系统,在不同的温度(pH＝7.4)条件下,测定了3,4,5－三羟基苯甲酸与漆酶反应的摩尔反应烙、米氏常数、反应速率常数、漆酶的活性并计算了结合能、活化自由能、活化能和活化烟等.在此基础上,应用过渡态理论,从能量变化的角度,对其催化过程进行了分析.由活化摘(△S_≠^T＜0)得出酶－底物过渡态的结构较酶－底物复合物更为有序的结论.     

混合溶剂系统中固定化脂肪酶对酮基布洛芬的催化酯化反应

以硅藻土吸附的脂肪酶为催化剂,对外消旋酮基布洛芬[2-(3-苯甲酰苯基)丙酸]进行对映选择性酯化反应;考察了不同的脂肪酶制剂,固定化时所加缓冲液的体积与pH值,酰基受体(醇)的种类以及混合溶剂系统的组成等因素对酶活性的影响.结果表明,在所考察的7种脂肪酶中,以LipaseOF的酪化活性最高;用硅藻土吸附固定化酶时,缓冲溶液的最适pH为7.0左右,每克酶粉加1.0mL缓冲溶液为最佳;固定化酶催化酯化的活性比游离的脂肪酶高.在酮基布洛芬与不同酰基受体(醇)的酶促酯化反应中,以丙醇的反应速度为最快.在由一种主溶剂与一种助溶剂组成的混合溶剂系统中,酶促酯化的速度要比在单一的主溶剂或助溶剂系统中快.当以1gP值较大的环己烷或异辛烷等为主溶剂,甲苯为助溶剂时,脂肪酶催化酮基布洛芬酯化反应的活性最高.     

酶催化水解法快速测定牛奶中蛋白质含量

以酪蛋白水解度为指标,采用pH-stat法优化了胰蛋白酶催化酪蛋白水解的反应条件,并以该酶为检测用酶,分析了酪蛋白浓度与酶解反应初速度的关系,并建立了一种快速检测牛奶中蛋白质含量的方法.在pH=7.5,温度55℃的条件下,用pH-stat法测得酪蛋白浓度与酶促蛋白质水解反应初速度呈良好线性关系.最后采用该酶催化水解法测...     

醇水介质中漆酶催化氧化漆酚及其类似物

本文作者在醇水介质中对漆酚及其类似物的酶催化氧化反应进行了研究。探讨了混合溶剂中漆酶的行为。结果发现邻苯二酚被烷基取代后更有利于漆酶的催化氧化。反应可能经过两个步骤,先是底物氧化生成黄色苯醌类物质,然后醌类中间物偶联形成多聚酚。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

Summary of development of the theory of stability of colloids and thin films

In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

Thermodynamics of the formation of oxosulfides of rare-earth elements

The enthalpies of solution of several oxosulfides of rare-earth elements and the high-temperature enthalpies of oxosulfides and oxosulfates of lanthanum and yttrium were measured using solution calorimetry and high-temperature microcalorimetry techniques. Standard enthalpies of formation and some thermodynamic properties of oxosulfides and oxosulfates were calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2 pp. 294–297, February, 1997.     

探究“铁的锈蚀条件”实验创新设计

设计了铁的锈蚀实验,说明了铁钉的处理方法,增加了温度、酸、碱的影响条件,实现了铁跟蒸馏水及空气中氧气快速反应而生锈,使实验在5 min左右就能够得到准确的结果。