Catalytic and Noncatalytic Ammonolysis of Polyfluorinated 1,3-Dichlorobenzenes

Reactions of 1,3-dichlorotetrafluorobenzene and 1,3-dichloro-2,4,6-trifluorobenzene with aqueous ammonia in the presence and in the absence of copper(I) salt lead to fluorine replacement by amino group in the para and ortho positions with respect to the chlorine atom. Ammonolysis of the resulting chloropolyfluoroanilines in the absence of a catalyst involves replacement of fluorine atom in the meta position with respect to the amino group. In the presence of copper(I) salt, catalytic aminodechlorination occurs at the para and ortho positions with respect to the amino group introduced in the first stage.     

Catalytic Mechanism of the Metal-Free Hydrogenase from Methanogenic Archaea: Reversed Stereospecificity of the Catalytic and Noncatalytic Reaction

By activation of the hydrogen acceptor , the metal-free hydrogenase from methanogenic archaea catalyzes the reduction of methenyl tetrahydromethanopterin with H₂. According to NMR spectroscopic analysis of the conformation of the hydrogen acceptor in solution and of the stereospecificity of the catalyzed and noncatalyzed reaction, in the enzyme-catalyzed reaction the hydrogenation product is formed in a constraint conformation which relaxes upon dissociation from the enzyme. This exergonic conformational change could help to avoid product inhibition of the enzyme.     

木素的氧化性氨化反应(英文)

在一定压力和温度条件下,木素大分子和氨发生反应,生成一些氮修饰木素.为了解反应过程中木素分子结构的变化,用13 C和1H - 13 C 2D -NMRHMQC技术检测了反应前后的分子谱图,结果显示反应过程中木素分子的碎裂化现象十分明显,很可能在氧化性氨化反应过程中,木素大分子表面基团发生了氧化性修饰,如一些侧链 -CH3 被氧化形成 -CHO和 -COOH等,然后这些基团与氨结合等;此外,芳香环结构可能通过粘康酸单体断裂形成一些酰胺类产物,但木素分子内部的高度缩合性结构没有明显的变化     

Oxidative Ammonolysis of Dialkylpyridines

The cluster approach was used to simulate the chemisorption of dialkylperidines on the surface of a vanadium oxide catalyst, involving active centers of various nature, and to assess the enthalpy of proton abstraction from the alkyl substituents. Under oxidative ammonolysis conditions, the order of the transformation of the substituents in unsymmetrical dialkylpyridines into the cyano group is determined by the enthalpy of their deprotonation.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 1, 2005, pp. 159–163.Original Russian Text Copyright © 2005 by Vorob’ev, Sembaev.     

Ammonolysis of technical lignins

The oxidative ammonolysis of hydrolysis lignin, cellolignin, and lignosulfonate takes place effectively with the greatest formation of a water-soluble fraction at 140–150°C in 2 h. On oxyammonolysis, cellolignin forms approximately twice as much water-soluble fraction as hydrolysis lignin, while lignosulfate desulfonates under conditions exceeding the optimum. The maximum amount of nitrogen in the water-soluble fraction of lignin (nitrogen-containing lignin) amounts to 9.0% for cellolignin and is 2–3% less for the others.M. V. Frunze Simferopol' State University. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 275–278, March–April, 1987.     

Ammonolysis and aminolysis reactions of dichlorodimethylsilane

The final composition of the products of ammonolysis of aminolysis of dichlorodimethylsilane depends on the reaction temperature, the concentration of the starting materials the nature of the solvent and of the organic groups bonded to silicon and to nitrogen. When dichlorodimethylsilane in excess reacts with methylamine, the condensation of the Si-Cl and Si-NH₂ groups to give the silazane bond is the basic reaction. The rate of the reaction is decreased by an increase of the length of the organic radicals on silicon or nitrogen. In the ammonolysis or aminolysis of organochlorosilanes with small organic groups the ratio of the rates of halogen displacement by amine and of condensation is the factor which determines whether aminosilanes or silazanes are formed. The yield of silazane falls as the difference in rates increases.     

Noncatalytic hydrophosphorylation and hydrothiophosphorylation of hydroxyaldehydes

Nucleophilic addition of secondary phosphone oxides and phosphine sulfides to 2-hydroxyacet-, 2-hydroxybenz-, and 3,4-dihydroxybenzaldehydes proceeds under mild conditions (48–50°C, THF) and allows tertiary phosphine oxides and phosphine sulfides with several hydroxyl groups to be prepared.     

Oxidative Ammonolysis of Birch Wood

The functional composition of oxidative ammonolysis products obtained from treatment of birch wood with ammoniacal ammonium persulfate using a mechanochemical method was studied.     

Ammonolysis of aziridinecarboxylic acid esters

The ammonolysis of 1-(2-methoxycarbonylvinyl)- and 1-(1,2-dimethoxycarbonylvinyl)-2-methoxycarbonylaziridines at normal pressure leads to 1-(2-methoxycarbonylvinyl)-and 1-(1,2-dicarbamoylvinyl)-2-carbamoylaziridines, respectively, whereas 1,3-diazabicyclo[3.1.0]hexan-4-one derivatives are formed under pressure.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 350–352, March, 1983.     

Ammonolysis of magnesiothermic tantalum powders

Tantalum nitrides are synthesized by ammonolysis of a mesoporous magnesiothermic tantalum powders. The effect of specific surface area of the powders and synthesis temperature on product composition is shown. Nitrogen content in the ammonolysis product of tantalum powder with a specific surface area of 56 m² g^–1 corresponds to oxynitride TaON exposed to 600°C for 1 h. The specific surface area of the oxynitride is 35 m² g^–1.     

Oxidative Ammonolysis of Wood Bark

The influence of temperature (75-100°C), ammonia concentration in solution (1-5%), and oxygen pressure (1-8 MPa) on the yield of the target product (insoluble residue) and nitrogen content in this product in treatment of pine bark with oxygen in aqueous ammonia (oxidative ammonolysis) was studied. The resulting samples were tested in agriculture as nitrogen-containing fertilizers.     

Oxidative Ammonolysis of Vegetable Raw Materials

The influence of the composition of lignocarbohydrate vegetable raw materials, process duration (15-120 min), amount of hydrogen peroxide (0.1-0.9 g per gram of raw materials), and amount of ammonia (0.25-1.5 g per gram of raw materials) on the yield of the target product and on the nitrogen content and the content of functional groups in it in mechanochemical treatment of vegetable wastes with hydrogen peroxide in aqueous ammonia (oxidative ammonolysis) was studied. Sorption and agrochemical testing of the resulting samples as nitrogen-containing ion exchangers and fertilizers was performed.     

Preparation of Nitroanilines by Ammonolysis of Multinitrobenzenes

Highly efficient ammonolysis of several multinitrobenzenes to the corresponding nitroanilines was achieved by aqueous ammonia. o-Dinitrobenzene on reaction with 8 equiv. of ammonia produce the o-nitroaniline in yields of 87%. Similar reactions with p-dinitrobenzene, m-dinitrobenzene, and trinitrobenzene produce p-nitroaniline, m-nitroaniline, and 3,5-dinitroaniline, in yields of 86%, 45%, and 84%, respectively.     

铜催化卤代芳烃氨解反应的研究进展

铜催化卤代芳烃进行氨解反应是构建碳氮键的重要方法。铜作为催化剂不仅便宜、丰富、相对低毒,而且可以通过几个氧化态进行循环催化。配体的发展则扩展了底物的适用范围,提高了官能团的兼容性和反应的选择性,使得该反应成为一种通用的制备芳胺的方法。本文以铜盐催化剂为线索,对该反应机理进行了简介,对近年来铜催化卤代芳烃的氨解反应的研究进展进行了综述和展望,并指出高活性和高选择性的催化体系依然有限,铜催化剂使用量仍然较大,氨和氯代芳烃的使用还不够广泛,而且关于该类反应详细机理的文献报道还缺乏。此外,发展一个新的、高效的和通用的氨解方法仍然显得极为迫切。     

Ammonolysis of 1,4-bis(dimethylchlorosilyl)benzene

The ammonolysis of 1,4-bis(dimethylchlorosilyl)benzene with ammonia forms heterocyclic compounds of low molecular weight. The main reaction product is the crystalline [CH₃)₂SiC₆H₄Si(CH₃)₂NH]₄, which polymerizes on heating with the formation of polymers possessing a relative viscosity of 0.15–0.4.