| 摘要 |
1467606 Unsaturated phosphonate esters SOC NATIONALE DES POUDRES ET EXPLOSIES 24 June 1975 [4 July 1974] 26732/75 Heading C2P [Also in Division C3] The invention comprises unsaturated phosphonate esters of the formula wherein R 1 and R 4 which may be the same or different are each -(CH 2 ) m - in which m is 0 or an integer, R 2 and R 3 which may be the same or different are H or alkyl and the total number of carbon atoms of the radicals R 1 , R 2 , R 3 and R 4 is less than or equal to 10. They may be obtained by heating a substantially stoichiometric mixture of diethyl hydroxymethyl phosphonate and a chloride of an unsaturated dicarboxylic acid containing from 4 to 14 C atoms, e.g. fumaric acid dichloride, under reflux in the presence of pyridine and an aromatic hydrocarbon solvent, e.g. benzene. The products are useful as flame-retardant additives for polyurethane foams and may be copolymerized with olefins or monomers of polyester resins to form flame-retardant thermoplastic products. |
