430-67-1Relevant articles and documents
Carboxylic Acid Participation in Amide Hydrolysis. Evidence That Separation of a Nonbonded Complex Can Be Rate Determining
Kluger, Ronald,Chin, Jik
, p. 2891 - 2897 (1982)
Maleamic acids derived from aliphatic amines of a wide range of basicity (compounds 1-8) undergo hydrolysis in solutions of acidity between 1E-4 M and 1 M hydrogen ion concentration by a mechanism involving participation of the carboxyl group at the adjacent amide.Kinetic analysis of the reaction (50 deg C) reveals that the identity of the rate-determining step (or steps) is a function of both the basicity of the leaving group and the acidity of the solution.At pH 4, the rate-determining step is O to N proton transfer to form a zwitterionic intermediate for compounds with weakly basic leaving groups.For compounds with more basic leaving groups, conversion of the zwitterionic intermediate to products is rate determining.In more acidic solutions, where proton transfer is facilitated, diffusion apart from the complex formed from C-N bond breakage of the zwitterionic intermediate is rate determining for compounds with the most basic leaving groups.C-N bond breakage is rate determining for compounds with the least basic leaving groups.This suggests that at pH 4 the breakdown of the zwitterion may also involve rate-determining diffusion.It is concluded that other facile elimination reactions may involve rate-determining diffusion and that changes in the rate-determining step can serve as an indicator of its occurrence and as a means of calibration of rate constants.It is also suggested that since pepsin may catalyze peptide hydrolysis by a carboxyl-participation mechanism, the occurrence of sequential covalent intermediates may exist to permit diffusion of the noncovalently held products.
Method for synthesizing 2, 2-difluoroethylamine by using high-boiling residue in R142b as raw material
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Paragraph 0025-0032, (2021/01/24)
The invention belongs to the technical field of fluorine chemical industry, and particularly relates to a method for synthesizing 2, 2-difluoroethylamine by using a high-boiling residue in R142b as araw material. The method is characterized in that under the catalytic action of a catalyst 1 and a catalyst 2, 2, 2-difluoro-1-chloroethane and an ammonia water solution react in a solvent to prepare2, 2-difluoroethylamine. According to the method, the use of expensive noble metal catalysts can be avoided, the adopted phase transfer catalyst can be dissolved in a water phase and an organic phaserespectively, and can be in full contact with reactants so that the reaction is relatively thorough, the reaction rate is increased, the reaction temperature, the reaction pressure and the reaction time are reduced, and the product yield is high; the method has the advantages of low reaction temperature, low reaction pressure, low equipment requirement strength and simple operation steps, and therectified solvent and ammonia water solution can be continuously recycled, thereby reducing the discharge of three wastes, lowering the environmental pollution, and lowering the production cost and post-treatment cost.
PROCESS FOR PREPARING 2,2-DIFLUOROETHYLAMINE FROM 2,2-DIFLUORO-1-CHLOROETHANE AND AMMONIA
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Page/Page column 4, (2012/07/28)
Process for preparing 2,2-difluoroethylamine, comprising the following steps: (i) mixing 2,2-difluoro-1-chloroethane and gaseous, liquid or supercritical ammonia in a pressure-stable, closed reaction vessel under a pressure in the range from 10 to 180 bar;(ii) reacting the reaction mixture at a reaction temperature in the range from 80° C. to 200° C.;(iii) letting down the reaction mixture and isolating 2,2-difluoroethylamine.
