Patent GB-748228-A (GB)
Title: Organic derivatives of tetravalent tin and compositions containing the same
IPC: C07F7/22
Filed: 1953-05-20
Abstract: A resinous composition comprises a chlorine containing synthetic resin, e.g. a chlorine containing polyvinyl resin or a copolymer of vinyl chloride with vinyl acetate, vinylidene chloride or styrene, and as a stabilizer an organo-tin compound wherein 2 or 3 valences of the tin atom are linked to alkyl or aralkyl radicals and each remaining valence is linked to a sulphur atom of a radical of a diester derived from a mercapto carboxylic acid having from 2 to 4 carbon atoms and a glycol containing from 2 to 6 carbon atoms and obtained by reacting said diester with the required triorgano-tin monohalide, diorgano-tin dihalide or diorgano-tin oxide, the quantities of reactants being chosen so that both sulphur atoms of the diester residue are linked to a tin atom.  In the examples, compositions are prepared containing a copolymer of vinyl chloride with vinyl acetate, dioctylphthalate and th reaction product of 1,2-propylene glycol thioglycolic acid diester with di-n-butyl-tin oxide having the formula <FORM:0748228/IV(a)/1> and a copolymer of vinyl chloride with vinyl acetate, commercial tricresyl phosphate and the reaction product of 1,4-butanediol thiopropionic acid diester with tribenzyl-tin chloride having the formula (C6H5CH2-)3Sn-(SCH2CH2COO CH2CH2CH2CH2OOCCH2CH2S) - Sn(- CH2C6H5)3 the said composition being soluble in a mixture of toluene and methyl ethyl ketone.ALSO:The invention comprises organo-tin compounds, wherein 2 or 3 valences of the tin atom are linked to alkyl or aralkyl radicals and each remaining valence of the tin atom is linked to a sulphur atom of a radical of a diester, said diester being formed from a mercapto-carboxylic acid having from 2 to 4 carbon atoms and a glycol containing from 2 to 6 carbon atoms, obtained by heating said glycol with the said mercapto-carboxylic acid to form the diester which is then reacted with the required triorgano-tin monohalide, di-organo tin dihalide or di-organo tin oxide, e.g. at an elevated temperature, the quantities of the reactants being chosen so that both sulphur atoms of the diester residue are linked to a tin atom.  The alkyl radicals may be methyl, ethyl, butyl, octyl, dodecyl or octadecyl radicals, and a suitable aralkyl radical is the benzyl radical.  Glycols mentioned are ethylene and 1,2-propylene glycol, and 1,4 - butanediol. Mercaptocarboxylic acids mentioned are thioglycollic, thiopropionic and thiobutyric acid.  In the examples the following compounds are prepared :- <FORM:0748228/IV(a)/1> from the 1,2-propylene glycol diester with thioglycollic acid and di-n-butyl tin oxide, <FORM:0748228/IV(a)/2> from the ethylene glycol diester with thioglycollic acid and di-n-butyl tin oxide, and <FORM:0748228/IV(a)/3> from the 1,4-butanediol diester with b -thiopropionic acid and tribenzyl tin chloride.  The Specification also states that when dibutyl tin oxide is reacted with the ethylene glycol diester of thioglycollic acid, the reaction product may contain a compound of the formula <FORM:0748228/IV(a)/4> in addition to the compound referred to in the examples.  The organo-tin compounds may be used as antioxidants and are useful for stabilizing chlorine containing organic compounds, e.g. chlorinated paraffins having from 10 to 40 carbon atoms per molecule.  A suitable quantity of stabilizer is 0.1 to 10 per cent by weight based on the compound to be stabilized.