Abstract:
A method is disclosed for the preparation of alicyclic ketenes, useful as intermediates in the preparation of lactams. The instant method consists in a heat treatment of an alicyclic acid, or its anhydride, in a matallic reactor exempt from nickel, at high temperatures but under subatmospherical pressures. A catalyst of the type XP(OR)3 wherein X is selected from the group consisting of oxygen, sulphur and selenium and R is an alkyl radical is preferred for accelerating the reactions. The temperatures are in the range from 550* to 750*C and the preferred pressure is under 100 millimeters of mercury. High yields and conversion rates are obtained and the purity of the end product is more than satisfactory. The method can be applied to the preparation of a number of alicyclic ketenes.
Abstract:
A method is disclosed for recovering lactams from acidic reaction mixtures, the improvement consisting in the fact that the extractant is an alkylsubstituted phenol the alkyl chain of which contains at least three carbon atoms, the alkyl substituent being capable of imparting to the phenol a lipophilic character. Monosubstituted and disubstituted phenols, such as isopropyl phenols, sec. and tert. butyl phenols, sec. and tert. amylphenols, di-sec. amylphenols and di-tert. amylphenols are preferred.
Abstract:
A method for the preparation of pure lactam is disclosed wherein a primary solution of the lactam in an organic phenolic solvent is supplemented by a compound miscible with the solution which is compatible with the primary solvent and is a solvent for the primary solvent but not for the lactam and susceptible of giving rise to precipitation of the lactam, the lactam being then separated from the mixture of the primary solvent and the compound which is a solvent for said primary solvent.