Abstract:
The disclosure is a process for recovering caprolactam monomer and oligomer from aqueous polycaprolactam extracts by removing the inorganic contaminants present therein.
Abstract:
This continuous process for preparing an aqueous mixture of .di-elect cons.-caprolactam and 6-aminocaproic acid and/or 6-aminocaproamide by involves, as the reductive amination step, continuously contacting 5-formylvaleric acid or an alkyl 5-formylvalerate in water as solvent with hydrogen and an excess of ammonia in the presence of a ruthenium on carrier, as a catalyst, wherein the carrier is at least one of titanium oxide or zirconium oxide. The aqueous mixture can be used to prepare .di-elect cons.-caprolactam.
Abstract:
A process is described for the purification of .epsilon.-caprolactam which involves hydrogenation of a water-.epsilon.-caprolactam mixture in the presence of a heterogeneous hydrogenation catalyst, wherein the .epsilon.-caprolactam-water mixture is contacted with gaseous hydrogen, upon which hydrogen dissolves in the .epsilon.-caprolactam-water mixture, and subsequently, this hydrogen-containing mixture is contacted with the hydrogenation catalyst. About 90-100% of the hydrogen is dissolved in the water-.epsilon.-caprolactam mixture.
Abstract:
The invention provides a process for producing high quality .epsilon.-caprolactam which comprises allowing crude .epsilon.-caprolactam obtained by gas phase Beckmann rearrangement of cyclohexanone oxime to contact with hydrogen at 100.degree.-200.degree. C. in the presence of a hydrogenation catalyst.
Abstract:
Crude capronitrile is purified by hydrogenation, subsequent treatment in an acidic medium and subsequent distillation in an alkaline medium, by a process in which(a) 6-aminocapronitrile is converted into crude caprolactam by reaction with water,(b) high boilers and low boilers are separated off from the crude caprolactam from step (a),(c) the crude caprolactam from step (b) is treated with hydrogen at from 50.degree. to 150.degree. C. and from 1.5 to 250 bar in the presence of a hydrogenation catalyst and, if desired, of a solvent to give a mixture A,(d1) mixture A in a solvent is passed, at from 30.degree. to 80.degree. C. and from 1 to 5 bar, over an ion exchanger containing terminal acid groups to give a mixture B1, or(d2) mixture A is distilled in the presence of sulfuric acid, any solvent present being removed before the addition of the sulfuric acid, to give a mixture B2, and(e) mixture B1 or mixture B2 is distilled in the presence of a base to give pure caprolactam.
Abstract:
The preparation of N-substituted 2-pyrrolidones (I) by the reaction of maleic acid, fumaric acid, or succinic acid or functional derivatives of these acids (compounds II) with a primary amine (III) or by the reaction of amides or imides derived from II and III under hydrogenating conditions in a synthesis stage followed by isolation, by distillation, of I and other volatile components from the resulting reaction mixture, in which the residues present following distillation are subjected to further hydrogenation treatment and the compound (I) thus formed is isolated by distillation.
Abstract:
Caprolactam is prepared in a process comprising(a) a Beckmann rearrangement of cyclohexanone oxime with oleum at from 70.degree. to 130.degree. C. in one or more rearrangement stages, and(b) aftertreatment of the reaction mixture obtained from the rearrangement stage in a delay zone at from 70.degree. to 110.degree. C. for from 10 to 600 minutes.
Abstract:
A process is provided for recovering epsilon-caprolactam of a purity in excess of 99.9 wt. %, in a two-stage distillation operation. Each stage comprises an evaporator and a rectification column having a pressure drop across the theoretical trays thereof of less than about 2.5 MBAR.
Abstract:
Process for the preparation of .omega.-lactams (in particular caprolactam)ith improved yields, by reaction of cycloaliphatic derivatives having the general formula: ##STR1## wherein n=3-13 with nitrosating agents in the presence of dehydrating agents, characterized by the fact that the reaction is carried out a low temperature which is constant between stages, and in all the zones of a stage and with particular concentrations of the dehydrating agent.