GB763344A - Improvements in or relating to vinyl ethers - Google Patents

Abstract

Polymers and copolymers are prepared from the vinyl ethers of nitro-alkanols, especially those containing 2 to 5 carbon atoms, of various alkanols substituted by pyridyl, acridyl, quinolyl and benzo-quinolyl groups and of 2-chloro-allyl alcohol. Polymerization and co-polymerization of the nitro-alkyl vinyl ethers yield combustible plastics; the co-polymers of the vinyl ethers of the heterocyclic alcohols with acrylonitrile have basic properties and fibres produced therefrom are capable of being dyed. The preparation of the vinyl ethers is described (see Group IV (b)). Specification 662,503, [Group IV (b)], is referred to.ALSO:Vinyl ethers are catalytically transetherified to other vinyl ethers by mixing together a vinyl ether free of substituents which destroy the catalyst, an alcohol which is free of non-tertiary aminoethyl or aminopropyl groups and of substituents which destroy the catalyst and which has a non-hydroxyl residue different from that forming the vinyl ether and a catalyst comprising a mercury salt of a carboxylic acid which in water gives a pKa value of 4 to 7, reacting the resulting mixture at between 0 DEG and 150 DEG C. by heating it or letting it stand, terminating the reaction by addition of an alkaline reagent, by washing out components of the reaction mixture when they are water-soluble or by flash-distilling at low pressure and recovering the transetherified vinyl ether. The transetherification is suitably effected by refluxing, if desired, under pressure; solvents may be present. Either of the reactants may be in excess. Specified catalysts are the mercury salts of acetic, oxalic, oleic, methoxy-acetic, 2-ethyl butyric and benzoic acids. They may be used in conjunction with a sodium or potassium salt of a weak carboxylic acid, e.g. mercury acetate with sodium acetate. Mercury acetate may also be used with a weak acid boiling higher than acetic acid. The catalysts may be formed by mixing a mercury salt of a strong acid, e.g. mercuric sulphate, with an alkali metal salt of the weak acid. Also, mercury acetate may be reacted with a higher boiling weak acid if desired, in the presence of a solvent, e.g. a vinyl ether and the liberated acetic acid distilled off. The vinyl ethers to be transetherified may be derived from saturated or unsaturated aliphatic, cycloaliphatic, aromatic and heterocyclic alcohols and glycols and many are specified. The alcohols reacted with these vinyl ethers may be acyclic or cyclic and contain substituents such as ether, ester, cyano, keto, hydroxy, nitro and tert.-amino groups and halogen atoms; many examples are given including ether-alcohols, hydroxy esters in which the hydroxy groups may be in the acid or alcohol residues, tert.-amino alcohols, heterocyclic alcohols and polyhydric alcohols. Some of the transetherified vinyl ethers, notably those derived from nitroalkanols and from certain heterocyclic alcohols, are stated to be novel; the nitro-alkyl vinyl ethers may be used in the preparation of combustible polymers and copolymers while the vinyl ethers of the heterocyclic alcohols may be copolymerized with acrylonitrile (see Group IV (a)). In typical examples: (1) n-octyl alcohol and ethyl vinyl ether, with mercuric acetate as catalyst, are refluxed and the mixture thereafter cooled, treated with potassium carbonate, distilled under reduced pressure and an azeotrope containing octyl vinyl ether is collected, treated with sodium and the octyl vinyl ether distilled off; (3) 2-methyl-2-nitro-1-propane is refluxed with vinyl ethyl ether using mercuric acetate and sodium acetate mixture as catalyst, and is thereafter cooled, washed with water, flash-distilled and the distillate is fractionated to give the nitro-alkyl vinyl ether as an azeotrope which is treated with caustic soda and distilled to recover the pure ether; (4) 2 - (b - hydroxyethyl) pyridine is reacted with ethyl vinyl ether as in (1), reaction is terminated by flash-distillation and 2-(2-vinyl oxyethyl) pyridine recovered; many alternatives to the pyridyl ethanol are mentioned including acridyl, quinolyl and benzo-quinolyl substituted alkanols; (7) ethylene cyanohydrin and isopropyl vinyl ether are reacted as in (3), the mixture then being washed and flash-distilled, the recovered cyano ethyl vinyl ether being catalytically hydrogenated to 3-ethoxy propylamine; ethylene chlorhydrin reacted similarly yields 2-chlorethyl vinyl ether. Other examples include the preparation of 2-chlorallyl vinyl ether, 1-methyl-3-ketobutyl vinyl ether, furfuryl vinyl ether and the vinyl ethers of hydroxyethyl acetate and ethyl lactate. Specification 662,503 is referred to.