芳香取代反应—ipso取代反应

谈到芳香取代反应,人们立刻会想到芳环上取代基的o~-、p-、m~-位上氢原子的取代反应。然而对另一类反应,即环上取代基本身的取代反应却少为人知。它是起始于试剂对芳环上取代基所在位置(ipso位)的进攻,进而置换了该取代基的反应。称作ipso取代反应。某些研究表明,试剂对氢原子所在位置的进攻与它对ipso位的进攻处于竞争状态,往     

依时计量学反应与非依时计量学反应

依时计量学反应与非依时计量学反应李汝雄（北京石油化工学院化工系１０２６００）化学反应计量式一般表示反应物与产物间的计量关系，总的计量式中不出现反应中间物。如反应步骤中出现中间物，由于中间物的积累，且随时间变化，反应物与产物的量间的关系在反应过程中将不...     

有机反应的竞争性

有机反应的竞争性胡秀贞（南京师范大学化学系，２１００２４）竞争反应是有机化学中一个相当普遍的反应，所以我们研究有机反应机理时，必须具有有关这个反应的热力学和动力学的基本知识。大家知道热力学研究的一个重要内容是反应的起始状态和终止状态的能量变化，而动力...     

多反应离子的质子转移反应质谱

在无放射性辉光放电离子源内, 采用不同试剂气体进行放电, 为质子转移反应质谱(PTR-MS)新增了强度在10⁵ cps量级的3种反应离子NH₄⁺, NO⁺和O₂⁺, 纯度大于95%; 测试了这3种反应离子的离子-分子反应特征. 采用H₃O⁺, NH₄⁺, NO⁺和O₂⁺等4种反应离子对同分异构体丙醛/丙酮进行检测发现, H₃O⁺和NH₄⁺均不能区分的丙醛/丙酮可采用NO⁺或O₂⁺进行区分. 结果表明, 增加反应离子不仅使PTR-MS的可检测有机物范围不再局限于质子亲和势(PA)大于H₂O的有机物, 还提高了PTR-MS区分同分异构体的能力.     

Friedel-Crafts反应的发现史

介绍Ｆｒｉｅｄｅｌ和Ｃｒａｆｔｓ在进行Ｇｕｓｔａｖｓｏｎ反应的实验过程中如何发现了Ｚｉｎｃｋｅ反应的本质,从而创立了以无水三氯化铝等金属卤化物为催化剂的烷基化和酰基化反应。     

Belousov—Zhabotinskii反应

一、引言化学振荡是现代化学前沿课题之一。化学振荡现象已引起人们极大的兴趣与广泛的重视,而研究得最为深入的化学振荡反应就是Belousov-Zhabotinskii反应。B-Z反应在均相化学振荡的研究发展上有着极为     

谈谈麦克尔反应

讨论了麦克尔（Ｍｉｃｈａｅｌ）反应及其在有机合成上的应用。     

水煤气变换反应初始微观反应动力学的模拟研究

用蒙特水罗方法对水气转移反应两种典型机理的寝反应动力学进行了研究。结果表明,Ｔｅｍｋｉｎ等人的氧化－还原机理中,无论反应物ＣＯ和Ｈ２Ｏ的相对浓度怎样变化,ＣＯ２和Ｈ２的初始生成速率总是相差很大。     

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。