Patent GB-651163-A (GB)
Title: Improvements in and relating to processes for the polymerisation of ethylenically unsaturated compounds
IPC: C08F36/04
Filed: 1948-06-25
Abstract: Polymers or copolymers of one or more ethylenically unsaturated organic compounds are obtained by polymerizing the compound or compounds in the presence of an azo compound in which at least one of the nitrogen atoms of the azo group is attached to a tertiary carbon atom which has attached thereto a nitrile group and a radical containing as a substituent a carboxyl group as such, or a carboxyl group in which the hydrogen atom is replaced by a monovalent cation such as sodium, lithium, potassium and quaternary ammonium salts, e.g. tetramethyl ammonium salt. Specified compounds are ethylene, isobutylene, styrene, butadiene, vinyl chloride, vinyl fluoride, vinyl acetate, vinyl propionate, vinylidene chloride and fluoride, vinyl butyl ether, vinyl methyl ketone, acrylonitrile, methyl methacrylate, methacrylamide, tetrafluorethylene, trifluorochloroethylene, 1,1 - difluoro - 2,2 - dichloroethylene; tetraethylene glycol dimethacrylate, diallyl diglycolate, diallyl carbonate, diallyl phthalate, ethylene bis-(allyl maleate); chloroprene and fluoroprene.  The polymerization may be effected by bulk, solution, e.g. in water or benzene, emulsion or granular methods and super-atmospheric pressures employed.  The preferred azo compounds have the formula: R.H.C(COOY) CH2.C(R1 (CN)N = N.C(CN) (R1) CH2.C(COOY)H.R where Y is a monovalent cation, R1 is an organic radical of 1-6 carbon atoms, and R is hydrogen or a hydrocarbon radical of 1-6 carbon atoms.  Specified are alpha, alpha1 - azobis - (alpha - methyl - gamma-carboxybutyronitrile); alpha, alpha1-azobis-(alpha - gamma, gamma - trimethyl - gamma-carboxybutyronitrile); alpha, alpha1-azobis (alpha - methyl - gamma - phenyl - gamma-carboxybutyronitrile); alpha, alpha1-azobis (alpha - propyl - gamma - carboxybutyronitrile).  Specifications 622,374, 623,472, 626,155, 631,225, 634,757, 641,679 and 649,934 are referred to.ALSO:Azo compounds in which at least one of the nitrogen atoms of the azo group is attached to a tertiary carbon atom which has attached thereto a nitrile group and a radical containing as a substituent a carboxyl group as such or a carboxyl group in which the hydrogen is replaced by a monovalent cation are prepared by treating with hydrazine, an oxo-carbonyl compound which also contains a carboxylic group, preferably in the form of a water-soluble salt, e.g. an alkali salt of a carboxyl-containing ketone, reacting the resulting azine with hydrogen cyanide and oxidizing with chlorine or bromine the resultant hydrazo compound to the desired carboxyl-containing azonitrile or its salt.  In an example, alpha, alpha1-azobis-(alpha - methyl - gamma - carboxybutyronitrile), melting point 120-123 DEG  C., is prepared from sodium levulinate and hydrazine hydrate following the above general procedure.  Other specified azo compounds are alpha, alpha1-azobis - (alpha - gamma, gamma - trimethylgamma-carboxybutyronitrile); alpha, alpha1-azobis-(alpha-methyl-gamma-phenyl-gamma -carboxybutyronitrile; alpha, alpha1 - azobis-(alpha - propyl - gamma - carboxybutyronitrile).  The azo compounds may be used as polymerization catalysts.  Specifications 622,374, 623,472, 626,155, 631,225, 634,757, 641,679, [all in Group IV (a)], and 649,934 are referred to.