Patent GB-1066295-A (GB)
Title: Process for the polymerisation of acrylonitrile
IPC: C08F20/44
Filed: 1964-04-03
Abstract: Acrylonitrile polymers are prepared by polymerizing acrylonitrile or copolymerizing acrylonitrile with at least one other monoethylenically unsaturated polymerizable monomer having a single -CH = C< group, the total of acrylonitrile and other monomer containing at least 50% by weight of acrylonitrile, in an organic solvent, which dissolves the polymer at room temperature or above, and in the presence of an oxidation-reduction catalyst system comprising a hydroperoxide of formula R-OOH, wherein R is an aliphatic, alicyclic or aromatic group, one of the C atoms of which is bonded to the -OOH group, and from 0.0001% to 5% by weight, based on the total weight of monomer, of one or more reducing compounds containing a sulphur atom and an oxygen atom, the sulphur atom of which is oxidizable by the hydroperoxide. Polymerization can be effected at temperatures ranging from - 70 DEG  to + 100 DEG  C., preferably from - 50 DEG  to + 50 DEG  C.  The catalysts may be added incrementally during polymerization, and the process can be operated in continuous manner.  Organic solvents specified are dimethylformamide, dimethylacetamide, g -butyrolactone, ethylene carbonate, dimethyl sulphoxide and mixtures of such solvents, or mixtures thereof with up to 25% by weight of other organic compounds such as alkanols, ketones, hydrocarbons and acetonitrile.  Many hydroperoxide catalysts are listed, the preferred ones being cumene, p-menthane, t-butyl, diisopropylbenzene and methyl ethyl ketone hydroperoxides. Suitable reducing compounds include sulphur sesquioxide and sulphur dioxide; sulphurous, hydrosulphurous and thiosulphurous acids; alkyl sulphoxylates, sulphites and thiosulphites having 1-4 carbon atoms in the alkyl groups; alkyl esters of sulphenic and sulphinic acids having 1-4 carbon atoms in the alkyl groups and the corresponding free acids; thionyl chloride and sulphuryl chloride (the latter forming SO2 in situ); compounds of the formulae <FORM:1066295/C3/1> where R1 is a C1- 7 hydrocarbon radical and X is halogen; and addition compounds of alkali metal bisulphites with aldehydes and ketones. Comonomers for the acrylonitrile include vinyl, isopropenyl and allyl carboxylate esters, allyl alcohol, acrylate and methacrylate esters, vinyl and vinylidene halides, acrylamide and methacrylamide and alkyl derivatives thereof, methacrylonitrile, styrene and substituted styrenes, vinyl pyridines, vinyl lactams, acrylic, methacrylic and chloroacrylic acids and salts thereof; vinyl cyclic imides, vinyl alkyl ketones, ethers and urethanes, vinyl sulphonamides, vinyl- and allyl-sulphonic acids and their alkali metal salts, salts of unsaturated alcohol esters of sulphuric and phosphoric acid, unsaturated dicarboxylic acids and esters, amides and ester-amides thereof, and ethylene, isobutylene and propylene.  Chain transfer agents, e.g. phenols and alkyl mercaptans such as t-dodecylmercaptan, may be present during polymerization and, also, acids such as oxalic or phosphoric acid.  Fillers and pigments may be included during polymerization or afterwards, when the polymer solutions are spun into fibres or filaments or cast to form films, sheets or other shaped articles.  In examples, acrylonitrile is homopolymerized and copolymerized with N-isopropyl-acrylamide, N,N-dimethyl acrylamide, methyl acrylate, methyl methacrylate, the acrylate ester of 2-norcamphanyl - methanol, 3 - methyl - 2 - norcamphanyl methacrylate, methacrylonitrile, 4-vinylpyridine, styrene and N-vinyl pyrrolidone.