GB1347134A - Process for producing polyphenylene ether - Google Patents

Abstract

1347134 Polyphenylene ethers ASAHIDOW Ltd 26 May 1971 [27 May 1970 8 Dec 1970] 17246/71 Heading C3R A polyphenylene ether, generally having a particle size of 5-500 microns, is prepared by the oxidative polymerization of 2,6-disubstituted phenol of the formula wherein R represents a linear C 1-4 alkyl group, R<SP>1</SP> represents a halogen atom, a C 1-4 alkoxy group or a C 1-4 alkyl group, with oxygen or a molecular oxygen containing gas, in the presence of a catalyst and a liquid reaction medium, and: (1) using 15-35% wt. of the said phenol; (2) using as reaction medium a solvent system which dissolves the phenol but not the polyphenylene ether having a # SP/C of 0À25 or more (measured in 0À5% CHCl 3 solution at 25‹ C.) obtained by the reaction; and (3) conducting the polymerization in 2 or more separate steps, in the first step the polymerization being carried out maintaining a homogeneous solution until a conversion of phenol to polymer of from 50-95% is attained, and in the subsequent reaction step (S), the reaction mixture obtained from the first step being further polymerized as the polyphenylene ether formed is precipitated. Suitable catalysts include a cuprous, cupric, cobalt or manganese salt together with a tertiary amine, or a cobalt chelate compound together with a chloride, carboxylate or nitrate of Co, Ni, or Fe, or the acetylacetonate of Mn, Fe, Co, Ni, Cu or Zn. The reaction medium may be a single solvent selected from dimethylformamide, dimethylacetamide, trimethyleneglycol, hexamethyleneglycol, dimethylsulphoxide, hexamethylphosphotriamide, methyl ethyl ketone, diethyl ketone, acetylacetone, benzyl methylketone and diethyl carbonate. Alternatively the reaction medium may be a mixture of (A) a solvent for the polymer comprising one or more of benzene, toluene, xylene, chloro-, dichloro-, nitro- or ethylbenzene, styrene, methyl-, chloro- or dimethylstyrene, methylene dichloride, CHCl 3 , CHBr 3 , dichloroethylene, trichloroethane, benzonitrile, furan, thiophene, cyclopentanone and cyclohexane, and (B) a non-solvent for the polymer comprising one or more of C 1-6 alkyl alcohol, benzyl alcohol, cyclopentanol, hexanol, water, acetonitrile, propionitrile, acrylonitrile, diethyl ether, tetrahydrofuran, pentane, nhexane, 2-methylpentane, n-octane cyclopentane or -hexane, or any one of the single solvents listed above. In the examples 2, 6-dimethyl phenol (Examples 1, 3, 4, 6) and 2-ethyl-6-npropyl phenol (Examples 2, 5) are polymerized using oxygen in the presence of the following solvents and catalysts: -(1) CHCl 3 , toluene; cobaltous chloride/ethylenediamine/salicylaldehyde in methanol; (2) n-propanol, xylene; cupric acetate/tri-n-butylamine in CHCl 3 ; (3) n-butanol, ethylbenzene; a cobalt chelate and Cu CH 2 CO.CH 2 CO(CH 3 ) 2 in methanol; (4) dichloroethylene, benzene; cuprous chloride/ pyridine in a methanol/n-propanol mixture; (5) acetonitrile, dimethylstyrene; manganese acetate / tri - n - butylamine / sodium methoxide in a diethyl carbonate/ethanol mixture; (6) propionitrile, xylene; cupric acetate/triethylamine/KOH in a CHCl 3 /isopropanol mixture.