Patent GB-788325-A (GB)
Title: Polymeric organo-tin compounds and process for their preparation
IPC: C07F7/22
Filed: 1955-05-12
Abstract: The invention comprises organo-tin compounds of formula: <FORM:0788325/IV (b)/1> wherein R1, R2, R3 and R4 are like o different alkyl or aryl radicals and n is \sF 1.  They may be prepared by condensing a tin monomethoxide of formula R1R3R4SnOMe either with itself or with a methoxide of formula R2R3R4SnOMe to obtain compounds wherein n = 1, or by condensation of two mols. of either or one of each of said monomethoxides with one or more mols. of a tin dimethoxide of formula R3R4Sn(OMe)2 to obtain compounds wherein n = 2 or n > 2, the condensation being carried out by heating in the presence of a small amount of water.  The condensation may be carried out under reduced pressure and at a temperature between 65 DEG  and 150 DEG  C.  Specified methoxides include tributyltin, trioctyl tin and triphenyl tin monomethoxides and dibutyl tin, dioctyl tin and diphenyl tin dimethoxides.  The starting materials may be prepared in situ by reacting the corresponding trialkyl tin chloride or dialkyl tin dichloride with sodium methoxide or with methanol in the presence of ammonia.  The condensation products may be used as stabilizers for polyvinyl resin chloride resin compositions.  Detailed preparations are given in the examples. Reference has been directed by the Comptroller to Specification 772,663.ALSO:The invention comprises organo-tin condensation polymers of formula <FORM:0788325/IV (a)/1> wherein R1, R2, R3 and R4 are like o different alkyl or aryl radicals and n is >1.  They may be prepared by condensing two mols. of a tin monomethoxide of formula R1R3R4SnOMe or one of each of tin methoxides of formula R1R3R4SnOMe and R2R3R4SnOMe with (n-2) mols. of a tin dimethoxide of formula R3R4Sn (OMe)2, the condensation being carried out by heating at a temperature of 65-150 DEG  C. in the presence of a small amount of water.  The reaction may be carried out under reduced pressure. Specified methoxides include tributyl tin, trioctyl tin and triphenyl tin monomethoxides and dibutyl tin, dioctyl tin and diphenyl tin dimethoxides.  The starting materials may be prepared in situ by reacting the corresponding trialkyl tin chloride and dialkyl tin dichloride with sodium methoxide or with methanol in the presence of ammonia.  In Example (4), tributyl tin chloride and dibutyl tin dichloride are reacted in solution in toluene with ammonia and methanol.  The separated ammonium chloride is filtered off and the toluene removed under vacuum.  Heating is continued in the presence of a small amount of water to give a product in which n=14. Organotin compounds of formula <FORM:0788325/IV (a)/2> wherein R1, R2, R3 and R4 are like o different alkyl or aryl radicals and n is \sF1 may be used as heat and light stabilizers in halogenated vinyl compositions. Polyvinyl chloride, polyvinyl chloride-polyvinylidene chloride and polyvinyl chloride-acrylonitrile compositions plasticized with dioctyl phthalate and stabilized by organo-tin compounds in which the hydrocarbon groups are butyl and phenyl are described in the examples.  Example (4) describes a film-forming composition comprising a vinyl chloride-vinyl acetate copolymer in methyl ethyl ketone stabilized with a compound of formula <FORM:0788325/IV (a)/3> and Example (5) describes a spinning solution comprising polyvinyl chloride in acetone-carbon disulphide stabilized with a compound of formula  <FORM:0788325/IV (a)/4> Reference has been directed by the Comptroller to Specification 772,663.