GB1044018A - Purification of lactams - Google Patents

Abstract

Lactams, produced by rearrangement of oximes derived by irradiating saturated cycloaliphatic hydrocarbons and nitrosyl chloride or a mixture of nitric oxide and chlorine are purified by contact with 0.01-10% of Mg, Al, Cu, Zn, a metal of the iron group, a chloride or carbonate of a Group IIA or IIB element, AlCl3 or an oxide of an element of Group IIIA or IIB or the iron group or of copper and distillation. Rearrangement of the oxime may be effected at 80-150 DEG C. by H3PO4, 80-100% H2SO4, oleum containing up to 10% SO3 or a solid catalyst. The lactams may have 5-12 carbon atoms, e.g. laurolactam, capryllactam, piperidone, oenanthlactam and omega-amino-decanoic acid lactam. They may be liquid or gaseous or dissolved in an inert solvent, e.g. an aliphatic, cyclo-aliphatic or aromatic alcohol. Catalysts specified are Zn amalgam, a Raney metal of the iron group, e.g. Ni, ZnCl2, CaCl2, ZnCO3, MgCO3, oxides of Fe, Zn, Al, Co and Ni and mixtures thereof. The metal may be granular and may be activated, e.g. by treating Zn or Al with I2 or a mercury salt. The purification may take place at 0-250 DEG C. in an inert atmosphere, e.g. H2, and the pressure may be atmospheric or above or below. A polymerization stabilizer, e.g. 2,4,6-tri-tert.-butyl-phenol may be present. The product may be distilled out batchwise or continuously and the mixture may be filtered prior to distillation. In Example (1) laurolactam is treated under an atmosphere of nitrogen with, Zn dust activated with mercuric chloride, nickelous oxide, ferrous oxide, cupric oxide, magnesium activated with iodine, zinc dust, zinc dust aluminium powder and copper powder activated with mercury, iron powder, CaCO3 and BaCl2. In Example (2) Raney nickel and Raney cobalt are used separately in admixture with Zn dust. In Example (5) methanol is used as a solvent. In Example (6) the lactam is capric lactam.ALSO:In Example 1 laurolactam prepared and purified by a particular process (see Division C2) is fused with 3% of hexamethylene diammonium adipate and heated at 270-280 DEG C. under a nitrogen atmosphere of superatmospheric pressure to polymerize it.