Patent application number | Description | Published |
20080230368 | Process for the purification of lactams - A method and a plant are disclosed for purifying lactams, particularly lactams obtained by cyclizing hydrolysis of aminonitrile. The purification of ε-caprolactam obtained by cyclizing hydrolysis of aminocapronitrile is described which includes eliminating the ammonia from the reaction medium of the hydrolysis, then recovering the lactam from said medium in purified form. The recovery is carried out by performing at least a distillation of the lactam in the presence of a base producing optionally a fronts fraction comprising compounds more volatile than the lactam, a fraction comprising the lactam to be recovered to the degree of desired purity and a distillation tails comprising the lactam and compounds less volatile than the lactam. The distillation tails are treated by various processes such as evaporation in thin layers to recover the major part of the caprolactam and recycling the latter in the purification process. | 09-25-2008 |
20100036169 | Preparation of Primary Diamines - Primary diamines are prepared by hydrogenation of a dinitrile compound in the presence of a catalyst, in particular hexamethylenediamine is prepared by hydrogenation of adiponitrile; the product diamines are recovered by distillation in several distillation columns mounted in series and the heavy impurities are separated from the second distillation. | 02-11-2010 |
20100292511 | PURIFICATION OF IMPURE HEXAMETHYLENEDIAMINES - Impure hexamethylenediamines and more particularly those hexamethylenediamines containing contaminating amounts of tetrahydroazepine (THA), or more generally contaminating amounts of imines, are purified by distillation carried out with a short retention time of the impure hexamethylenediamine in the distillation column; the hexamethylenediamine obtained has a very low concentration of THA. | 11-18-2010 |
20120220798 | METHOD FOR CARBOXYLIC ACID ESTERIFICATION - The present invention relates to a method for esterification from alcohols and carboxylic acids using a heterogeneous catalyst, wherein the esterification reaction is performed at high temperatures enabling an improvement in the compromise between selectivity, conversion, and kinetics in various types of devices for implementing the method. | 08-30-2012 |