Patent GB-899665-A (GB)
Title: Activators for the polymerisation of 2-pyrrolidone
IPC: C08G69/24
Filed: 1960-04-05
Abstract: A process for polymerizing 2-pyrrolidone comprises forming a mixture comprising (1) 2-pyrrolidone, (2) an alkaline catalyst selected from alkali metals; carbonates and pyrrolidone salts of alkali metals; alkyl and aryl salts of alkali metals; hydrides, hydroxides and oxides of alkali and alkaline earth metals, said catalyst being employed in an amount ranging from 0,002 to 0,25 chemical equivalents of catalyst based upon one mole of pyrrolidone, and (3) an activator selected from (a) adipimide in an amount of 0,0001 to 0,075 chemical equivalents per mole of monomeric 2-pyrrolidone; (b) an organic carbonyl compound selected from aromatic carbonyl halides and N-carbonyl pyrrolidone having the formula <FORM:0899665/IV (a)/1> wherein R is hydrogen or an alkyl or substituted group containing 1 to 8 carbon atoms in admixture with an organic acid amide having the formula <FORM:0899665/IV (a)/2> where R1 is hydrogen, a phenyl radical or an alkyl radical having 1 to 8 carbon atoms, and R2 is hydrogen or an alkyl radical having 1 to 8 carbon atoms; and (c) an aromatic carbonyl halide admixed with adipimide wherein said organic carbonyl compound of (b) or said aromatic carbonyl halide of (c) is employed in a range of 0,0001 to 0,075 chemical equivalents per mole of monomeric pyrrolidone and wherein said acid amide of (b) or adipimide of (c) is employed in a range of 0,00005 to 0,075 chemical equivalents per mole of pyrrolidone, and subjecting said mixture to polymerization conditions until said monomer is polymerized. Specified catalysts are sodium, potassium, lithium and the carbonates, hydroxides, hydrides and oxides thereof, butyl lithium, sodium phenyl, sodium, potassium and lithium pyrrolidone and calcium and barium hydrides. Specified aromatic monocarbonyl halides are benzoyl chloride, benzoyl fluoride, benzoyl bromide, 1-naphthoyl halides, 2-naphthoyl halides, o-, m- and p-toluyl halides, xyloyl halides, phenyl acetyl chloride, 2-phenyl propionyl chloride and mixtures thereof.  N-monocarbonyl pyrrolidones specified are N-formyl pyrrolidone, N-acetyl pyrrolidone, N-propionyl pyrrolidone, N-butyryl pyrrolidone and N-valeryl pyrrolidone.  Specified organic acid amides are formamide, acetamide, propionamide, butyramide, valeramide, g -hydroxybutyramide, g -methyl butyramide, N-ethyl formamide, N-ethyl acetamide, N,N-dimethyl formamide and N,N-dimethylacetamide.  In a preferred embodiment of the invention, the 2-pyrrolidone and catalyst are reacted and subjected to vacuum distillation to remove water of reaction prior to addition of the activator.  Solution, emulsion, suspension or bulk polymerization may be used in the process of the present invention.  The 2-pyrrolidone may be copolymerized with other lactams, e.g. S -caprolactam.  In the examples, 2-pyrrolidone is polymerized in the presence of:- (III) and (V) sodium hydride, benzoyl chloride and N,N-dimethylamide; (IV) sodium hydride, benzoyl chloride and g -hydroxybutyramide; (VI) potassium hydroxide, benzoyl chloride and N,N-dimethyl formamide; (VII) sodium hydroxide, benzoyl chloride and N,N-dimethyl formamide; (IX) and (X) sodium hydride, N-acetyl pyrrolidone and N,N-dimethyl formamide; (XI) sodium hydride and adipimide and (XII) sodium hydride, adipimide and benzoyl chloride.