Abstract:
The present disclosure discloses a method for preparing caprolactam including: (1) contacting cyclohexanone oxime with a catalyst to carry out reaction in the presence of ethanol and under the condition of gas phase Beckmann rearrangement reaction of cyclohexanone oxime; (2) separating the reaction product obtained in step (1) to produce an ethanol solution of crude caprolactam, and then separating the ethanol solution of crude caprolactam to obtain ethanol and crude caprolactam; (3) removing impurities with boiling points lower than that of caprolactam in the crude caprolactam to obtain a light component removal product; (4) mixing the light component removal product with a crystallization solvent to carry out crystallization and solid-liquid separation to obtain a crystalline crystal; (5) subjecting the crystalline crystal to a hydrogenation reaction; wherein the crystallization solvent contains 0.1-2 wt % of ethanol.
Abstract:
Disclosed herein is an efficient, economical, industrially advantageous, straight-through process for the preparation of cyclic amides, also referred as lactams, in substantially pure form and high yield, from the corresponding cyclic ketones and a hydroxylammonium salt, using a combination of amphoteric metal oxide or amphoteric masked metal oxide and a base.
Abstract:
A process for the recovery of ε-caprolactam from extract water of polycaprolactam obtained by hydrolytic polymerization, wherein the extract water is concentrated, subsequently contained oligomers are depolymerized, non-depolymerizable impurities are separated, water and low-boiling impurities are removed, wherein for adjusting the purity of the recovered ε-caprolactam and the energy consumption used for the process a part of the product is removed from the process as intermediate products.
Abstract:
A compound of the formula (I): wherein X is hydroxy or the like; Y is —C(═R2)—R3—R4 wherein R2 and R3 is oxygen atom or the like, R4 is hydrogen, optionally substituted alkyl, optionally substituted heteroaryl or the like; Z is hydrogen or the like; Z1 and Z3 each is independently a bond, alkylene or the like; Z2 is a bond, alkylene, —O— or the like; R1 is optionally substituted aryl, optionally substituted heteroaryl or the like; p is 0 to 2 and ring (A) is optionally substituted aromatic heterocycle, a tautomer of itself, a prodrug thereof, a pharmaceutically acceptable salt thereof or a solvate thereof has an integrase-inhibiting activity.
Abstract:
A system for purifying an aqueous solution of crude caprolactam is provided, which includes a filtration zone (A), an inspection unit (B), a purification zone (C), and a first temporary storage tank (D). The filtration zone (A) contains a filtration apparatus though which an aqueous solution of crude caprolactam is filtered to remove ionic impurities therein, so as to obtain caprolactam-containing filtrate; the inspection unit (B) is used for judging the filtrate from the filtration zone (A) meets the preset inspection standards; the purification zone(C) is used for concentrating and further purifying filtrate meeting the preset inspection standards, thereby forming a final caprolactam product; and the first temporary storage tank (D) is used for receiving the filtrate not meeting the preset inspection standards, which is then mixed with the aqueous solution of crude caprolactam and delivered back to the filtration zone (A).
Abstract:
This invention relates to a continuous and efficient method for the manufacture of highly pure caprolactam suitable for the polycondensation of Polyamide 6 (polycaprolactam) from polyamide waste. In particular the invention relates to a method for the manufacture of caprolactam from waste containing polyamides, including the steps a) depolymerisation of the waste containing polyamides, whereby a caprolactam raw material and a flow containing secondary constituents or additives is obtained, b) at least one distillation of the caprolactam raw material, and c) at least one crystallisation of the caprolactam material obtained in step b), by which means caprolactam is obtained, whereby at least part of the caprolactam obtained in step c) with a permanganate number of
Abstract:
Process for recovering caprolactam from a solution comprising caprolactam dissolved in an organic solvent, said process comprising: a) washing the solution with water or an aqueous alkaline solution, resulting in a washed solution comprising caprolactam and organic solvent and in a washing residue, b) evaporating organic solvent from the washed solution, resulting in caprolactam product, c) optionally, hydrogenating the caprolactam product, d) optionally, evaporating water from the caprolactam product, e) distilling the caprolactam product to recover caprolactam and a distillation residue, f) extracting the distillation residue with an organic solvent in the presence of water to obtain (i) an extract comprising caprolactam dissolved in organic solvent and (ii) an aqueous effluent, and g) recycling the extract to step a) or b).
Abstract:
A process is provided for the separation of ammonia (I) from mixtures (II) containing ammonia (I) and an amide (IV) selected from the group consisting of a lactam (IVa), an oligomer (IVb) and a polymer (IVc) with amide groups in the main chain, said amide (IV) having been obtained by reacting educts (III), selected from the group consisting of nitrites (IIIa), amines (IIIb), amino nitrites (IIIc) and amino amides (IIId), with water, wherein a) the educt (III) is reacted with water in the liquid phase, in the presence of an organic liquid diluent (V), to give a mixture (II) containing the amide (IV) and the ammonia (I), the diluent (V) exhibiting a miscibility gap with water under certain quantity, pressure and temperature conditions, b) the mixture (II) is converted under quantity, pressure and temperature conditions such that the diluent (V) and the water are in liquid form and exhibit a miscibility gap, to give a two-phase system consisting of a phase (VII) containing a higher proportion of diluent (V) than water, and a phase (VIII) containing a higher proportion of water than diluent (V), c) the phase (VII) is separated from the phase (VIII), d) all or part of the ammonia present in the phase (VII) is separated off by extraction (a) with a water-containing mixture (IX) to give an aqueous mixture (X) containing the ammonia which has been separated off, and a mixture (XI) containing less ammonia than the phase (VII), and e) the diluent (V), any residual ammonia and any by-products selected from the group consisting of low-boiling components, high-boiling components and unreacted compounds (III) are separated from the mixture (XI) to give the amide (IV).
Abstract:
The invention relates to a process for the separation of a ketoxime or aldoxime from a ketoxime- or aldoxime-containing amide mixture in which the ketoxime or aldoxime is separated from the amide mixture by means of distillation. This has proved to be a very simple and direct method for separating the ketoxime and/or aldoxime from the desired amide.
Abstract:
The present invention provides an improved process for the recovery of caprolactam from polycaprolactam processing waste. The present process for depolymerizing polycaprolactam waste to form caprolactam comprises the step of: in the absence of added catalyst, contacting the polycaprolactam waste with superheated steam at a temperature of about 250.degree. C. to about 400.degree. C. and at a pressure within the range of about 1.5 atm to about 100 atm and substantially less than the saturated vapor pressure of water at the temperature wherein a caprolactam-containing vapor stream is formed.The formed caprolactam may then be used in the production of engineered resins and fibers.