Patent GB-669790-A (GB)
Title: Improvements in or relating to organopolysiloxanes
IPC: C08G77/00
Filed: 1950-04-04
Abstract: An organo-polysiloxane comprises organic groups each of which is carboxyphenyl, methyl, phenyl or tolyl, there being from 0.5 to 3 organic groups per silicon atom and from one carboxyphenyl group per 4000 silicon atoms to one carboxyphenyl group per silicon atom, all remaining silicon valencies being satisfied by oxygen. The polymers may be prepared (a) by oxidation of tolyl groups in polysiloxanes containing such groups with alkaline potassium permanganate or by air blowing at elevated temperatures in the presence of, e.g., MnO2 or Cr2O3; (b) by preparing Grignard reagents from the corresponding halogeno-phenylsiloxane, carbonating the Grignard reagent with carbon dioxide and acidifying; (c) catalytic copolymerization of carboxyphenylsiloxanes with the appropriate alkyl or acyl siloxanes. The polymers are useful per se as lubricants, high temperature resins and coating agents or as intermediates in the preparation of polyester and polyamide type polymers by reacting the carboxyphenylsiloxanes with polyhydric alcohols and diamines respectively; e.g. a mixture of isomeric 1.3 carboxy-phenyltetramethyldisiloxanes may be reacted with ethylene diamine to produce a resin that can be drawn into threads.  A similar product is produced with ethanolamine and 1.3-di-p-carboxyphenyltetramethyldisiloxane.  From one part amine to 200 parts siloxane to 2.5 parts amine to 1 part siloxane may be used, the reaction proceeding on mixing and heating above 100 DEG  C. In examples: (1) to (6) various tolysiloxanes were oxidized with alkaline potassium permanganate to give carboxyphenylsiloxanes; the starting materials were (1) and (2) a mixture o-, m-, and p-isomers of tolysilsesquioxane; (3) a mixture of o-, m-, and p-isomers of tolylmethylsiloxane; (4) a copolymer of composition 35 mol. per cent CH3C6H4SiO3/2, and 65 mol. per cent CH3SiO3/2; (5) a copolymer of equal parts CH3C6H4SiO3/2, (CH3)2SiO and CH3SiO3/2; (6) a copolymer of 25 mol. per cent CH3C6H4 SiO3/2, 70 mol. per cent (CH3)2SiO and 5 mol. per cent C6H4(CH3)2SiO1/2; the products of examples (3)-(6) were soluble in concentrated ammonium hydroxide; (7) a mixture of isomeric tolyl methyl siloxanes in pyridine solution was oxidized with potassium permanganate, filtered, extracted with benzene and acidified to give a copolymer having one carboxyphenyl group per 3900 Si atoms.  A sample heated with glycerol set to a soft gel; (8) tetramethyl-1,3-di-p-bromophenyldisiloxane was added to magnesium shavings in ether, the product being added to an excess of solid carbon dioxide and the mixture hydrolysed in acid to give 1.3-di-p-carboxyphenyltetramethyldisiloxane, the ammonium, sodium, copper and iron salts of which were then prepared; (9) the product of (8) was copolymerized with octamethylcyclotetrasiloxane, the product being soluble in ether; (10) copolymers of octamethylcyclotetrasiloxane with (a) carboxyphenylsilsesquioxane and (b) carboxyphenylmethylpolysiloxane were prepared.ALSO:Organo-siloxanes having from 0.5 to 3 organic groups per silicon atom and in which the organic groups are each carboxyphenyl, tolyl, phenyl or methyl, there being from one carboxyphenyl radical per 4000 silicon atoms to 1 carboxyphenyl radical per silicon atom, are prepared by (a) oxidation of appropriate tolyl siloxanes to convert some or all the tolyl radicals into carboxyphenyl radicals; (b) carbonation and subsequent acidification of Grignard reagents from appropriate halogenophenylsiloxanes; or (c) catalytic copolymerization of carboxyphenylsiloxanes with appropriate alkyl and/or aryl siloxanes. Oxidation may be effected by alkaline potassium permanganate or by air blowing at elevated temperatures in the presence of MnO2 and Cr2O3.  Tetramethyl - 1,3 - di - p - carboxyphenyldisiloxane is prepared by adding magnesium shavings to tetramethyl-1,3-di-p-bromophenyldisiloxane in anhydrous ether, the resulting Grignard reagent being added to a large excess of powdered solid CO2 in ether, and the carbonated mixture hydrolysed with hydrochloric acid, extracted with sodium hydroxide and acidified. The product after recrystallization melts at 243 DEG  to 244 DEG  C. and gives water-soluble ammonium, sodium, copper and iron salts.