Patent GB-635733-A (GB)
Title: Improvements in or relating to the manufacture of organo silicon esters
IPC: C08G77/38
Filed: 1947-08-26
Abstract: Organo-silicon esters are produced by reacting a siloxane in which all the valencies of the silicon atoms are satisfied by hydrocarbon radicals, chloromethyl radicals and oxygen atoms, with a metal salt of a carboxylic acid in the presence of a solvent for the salt, whereby the chloromethyl radicals are converted to acyloxymethyl radicals.  The solvent may be the acid or anhydride corresponding to the metal salt.  Hydroxy derivatives of the products, obtainable by alcoholysis, are suitable for the manufacture of polyurethane resins. In examples (1) compounds of formula <FORM:0635733/IV (a)/1> and <FORM:0635733/IV (a)/2> are obtained by heating together chloromethyl pentamethyl disiloxane and anhydrous potassium acetate in acetic acid solution; (2) bischloromethyl tetramethyl disiloxane is used in place of the disiloxane of (1); (3) a polymeric siloxane containing methyl and acetoxy-methyl radicals is produced by heating chloro-methyl heptamethyl cyclotetrasiloxane with potassium acetate; (4) heating together symmetrical bis-chloro-methyltetramethyldisiloxane, sodium benzoate, and benzoic acid yields symmetrical bis-benzoxymethyl tetramethyl disiloxane; (5) a chloro-methyl methyl siloxane polymer obtained from chloro-methyl methyl silicon dichloride is heated with sodium acetate and acetic acid; (6) dichloro-(chloromethyl)-methyl siloxane is reacted with phenyl magnesium bromide to yield a mixture of (chloromethyl)-methyl diphenyl silane and chloro-)chloromethyl)- methyl phenyl silane.  The latter is hydrolysed to the siloxane <FORM:0635733/IV (a)/3> , which is reacted with potassium acetate to give symmetrical bis - (acetoxy - methyl)-dimethyldiphenyldisiloxane.ALSO:Organo-silicon esters are produced by reacting a siloxane in which all the valencies of the silicon atoms are satisfied by hydrocarbon radicals, chloromethyl radicals, and oxygen atoms, with a metal salt of a carboxylic acid in the presence of a solvent for the salt, whereby the chloromethyl radicals are converted to acylmethoxy radicals.  The solvent may be the acid or anhydride corresponding to the metal salt.  In examples: (1) compounds of formula <FORM:0635733/IV (b)/1> and <FORM:0635733/IV (b)/2> are obtained by heating together chloromethyl pentamethyl disiloxane and anhydrous potassium acetate in acetic acid solution; (2) bischloromethyl tetramethyl disiloxane is used in place of the disiloxane of (1); (3) a polymeric siloxane containing methyl and acetoxy-methyl radicals is produced by heating chloromethyl heptamethyl cyclotetrasiloxane with potassium acetate; (4) heating together symmetrical bischloromethyl tetramethyl disiloxane, sodium benzoate, and benzoic acid, yields symmetrical bis-benzoxymethyl tetramethyl disiloxane; (5) a chloromethyl methyl siloxane polymer obtained from chloromethyl methyl silicon dichloride is heated with sodium acetate and acetic acid; (6) dichloro-(chloromethyl)-methyl siloxane is reacted with phenyl magnesium bromide to yield a mixture of (chloromethyl)-methyl diphenyl silane and chloro-(chloromethyl)-methyl phenyl silane.  The latter is hydrolysed to the siloxane <FORM:0635733/IV (b)/3> which is reacted with potassium acetate to give symmetrical bis - (acetoxy - methyl) - dimethyl-diphenyldisiloxane.