| 摘要 |
Polymers of acrolein, methacrolein and vinyl alkyl ketones in which the alkyl group has 1 to 4 carbon atoms, or copolymers thereof with styrene and alkyl methacrylates in which the alkyl group has 1 to 4 carbon atoms, are condensed with aminoguanidine or salts thereof, e.g. the bicarbonate, acetate and butyrate. The condensation may be effected at subatmospheric, atmospheric or superatmospheric pressures in inert media, e.g. 1,4-dioxane, glacial acetic acid or mixtures thereof, isopropyl alcohol and isopropyl alcohol-water mixtures, and the products decolourized with reducing agents, e.g. sodium and potassium bisulphites and metabisulphites, sulphur dioxide, sodium and potassium dithionites and metallic zinc and acetic acid. The polymers may be prepared by polymerization in bulk or solution, e.g. in dioxane and isopropyl alcohol, in the presence of catalysts, e.g. benzoyl peroxide. The polymers may be used as mordants in photographic processes in and for over-coating gelatino-silver halide emulsion layers, and in imbibition and dye transfer blanks. Specifications 522,997, 654,266, 796,401 and U.S.A. Specification 2,739,137 are referred to.ALSO:Propionyl chloride is added dropwise to a cooled suspension of aluminium chloride in methylene chloride and gaseous ethylene passed through the cooled, stirred mixture which is worked up to recover 1-chloro-pentanone-3. A mixture of 1-chloropentanone-3 and N, N-diethyl-aniline is heated rapidly and the product which distils during the vigorous reaction is fractionated twice to recover vinyl ethyl ketone. Specifications 522,997, 654,266, 796,401 and U.S.A. Specification 2,739,139 are referred to.
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