Patent GB-880782-A (GB)
Title: Process for reducing reducible chemical substances soluble in organic solvents
IPC: C08F4/12
Filed: 1958-02-06
Abstract: In a process for reducing reducible chemical substances which are soluble in organic solvents the substance to be reduced is reacted with an organosilicon compound containing at least some hydrogen atoms bonded to silicon atoms by an H-Si bond in the presence of an organic solvent or diluent medium and as catalyst a metallic compound other than chloroplatinic acid which is soluble in the organic solvent or diluent.  There may be present in the reaction mixture a compound containing an active hydrogen atom. Organosilicon compounds mentioned include organo silanes and organosiloxanes containing silicon bonded hydrogen atoms. Examples compounds containing active hydrogen mentioned are water, alcohols and acids.  Metal compounds mentioned for use as catalysts include organo-metallic compounds, e.g. dibutyl tin dilaurate and dimaleinate and phenyl mercury acetate, nickel dibutyl dithiocarbaminate and metal salts of organic acids.  In examples: hydrogen sulphide is obtained by reducing sulphur with linear methyl hydrogen polysiloxane in the presence of carbon disulphide, ethanol and aluminium chloride (6); titanium subchloride is apparently formed by reacting titanium tetrachloride with linear methyl hydrogen polysiloxane (7); tin hydride is obtained by reacting tin tetraricinoleate with linear methyl hydrogen polysiloxane (9) and by reacting dibutyl tin dilaurate with methyl hydrogen polysiloxane (10).ALSO:Organosilanes and organosiloxanes containing hydrogen atoms bonded to silicon are employed for reducing reducible chemical substances (see Groups II, III and IV(b)), the reaction being effected in the presence of an organic solvent or diluent medium and as catalyst a metal compound other than chloroplatinic acid which is soluble in the organic solvent or diluent medium.  A compound containing an active hydrogen atom may be present in the reaction mixture.  Organosilicon compounds specified include low molecular weight cyclic organohydrogen siloxanes, e.g. trimethyl trihydrogeno cyclic trisiloxane [CH3 Si HO]3 or linear organohydrogenosiloxanes (CH3)3 Si(CH3 Si Ho)x Si(CH3)3).  The organic substituents present in the siloxanes and silanes can be any of the monovalent hydrocarbon radicals many of which are listed. Examples of compounds containing active hydrogen are water, alcohols and acids.  Metal compounds for use as catalysts include organometallic compounds, e.g. dibutyl tin dilaurate and dimaleinate, phenyl mercury acetate, nickel dibutyl dithiocarbaminate and metal salts of organic acids.  Substances specified for reduction include fatty acids, aldehydes, ketones, nitrocompounds and unsaturated organic compounds.  In examples, acetophenone is reacted with (CH3Si HO)3 in the presence of ethanol and dibutyl tin dilaurate (1); linear methyl hydrogen polysiloxane is reacted with acetone in a similar process (2); nitrobenzene ethyl hexanol and dibutyl tin dilaurate (3); m-dinitrobenzene in the presence of ethyl hexanol and dibutyl tin dilaurate (4); acetone in similar process to (3)(5); sulphur in the presence of carbon disulphide ethanol and aluminium chloride (6); titanium chloride and butyl titanate in benzene containing butyl alcohol (7); butyl titanate and butyl alcohol (8), (11); tin tetraricinoleate in the presence of methanol (9) and dibutyl tin dilaurate (10).  The compound (CH3 Si HO)3 may be replaced by phenylhydrogen siloxane, vinyl hydrogeno siloxane, copolymeric phenyl-methyl methylhydrogenosiloxane, copolymeric benzylbutyl-tolylhydrogensiloxane or ethylhydrogensiloxane. Polystyrene having silicon organic terminal groups is obtained by heating the mixture of products from the reduction reaction in Example 8 with styrene in toluene solution.  Other polymerizable vinyl compounds and ethylene may be similarly polymerized.ALSO:In a process for reducing reducible chemical substances which are soluble in organic solvents the substance to be reduced is reacted with an organosilicon compound containing at least some hydrogen atoms bound to silicon atoms by an H-Si bond in the presence of an organic solvent or diluent medium and as catalyst a metallic compound other than chloroplatinic acid which is soluble in the organic solvent or diluent medium.  There may be present in the reaction mixture a compound containing an active hydrogen atom.  Organosilicon compounds mentioned include organisilanes and organosiloxanes containing silicon bonded hydrogen atoms, e.g. low molecular weight cyclic organo-hydrogen siloxanes, e.g. trimethyltrihydrogeno cyclic trisiloxane [CH3SiHO]3 or linear organo-hydrogeno - siloxanes (CH3)3Si(CH3SiHO)x Si(CH3)3.  The organic substituents present on the siloxanes and silanes can be any of the monovalent hydrocarbon radicals, e.g. alkyl radicals, e.g. methyl, propyl or octodecyl; aryl radicals, e.g. phenyl and anthracyl, alkaryl radicals, e.g. tolyl and methylnaphthyl, aralkyl, e.g. benzyl and phenylethyl; cycloaliphatic, e.g. cyclopropane and cyclopentane and alkenyl, e.g. vinyl and alkyl. Examples of compounds containing active hydrogen mentioned are water, alcohols and acids.  Metal compounds for use as catalysts mentioned include organometallic compounds, e.g. dibutyl tin, dilaurate and dimaleinate and other tin dialkyl diacylates and phenyl mercury acetate, nickel dibutyl dithiocarbaminate and metal salts of organic acids.  Compounds specified for use as starting materials include acids including fatty acids, aldehydes, ketones, nitrocompounds and unsaturated organic compounds.  In examples: Phenyl methyl carbinol is obtained by heating acetophenone with ethanol, dibutyl tin dilaurate and (CH3SiHO)3 adding water and extracting the product with trichlorethylene (1); linear methyl hydrogen polysiloxane is employed in a similar process and the product treated with dilute sulphuric acid before extraction (2); aniline is obtained by boiling nitrobenzene in admixture with ethyl hexanol, dibutyl tin dilaurate, linear methyl hydrogen polysiloxane and ethyl alcohol apparently with separation of metallic tin (3); phenylene diamine is obtained by treating m-dinitrobenzene in ethyl hexanol solution and in the presence of dibutyl tin dilaurate with linear methyl hydrogen siloxane and treating the reacted mixture with dilute hydrochloric acid and extracting with caustic soda before isolating the desired product (4); isopropanol is obtained by reducing acetone in a similar process to (3) (5); butyltitanate in benzene solution containing some butyl alcohol is treated with linear methyl hydrogen polysiloxane to obtain a dark blue solution of compounds of low valency titanium and subsequently titanium (7); a blue coloured solution is obtained by reacting linear methyl hydrogen polysiloxane and butyl titanate containing free butanol (8) a mixture of titanium compounds of valency below 4 is obtained by treating a mixture of monomeric butyl titanate, butanol and methyl hydrogen polysiloxane under nitrogen (11).  The compound represented by the formula (CH3SiHO)3 may be replaced in examples by phenyl hydrogen siloxane vinyl hydrogen siloxane, copolymeric phenyl methyl-methyl hydrogen siloxane, copolymeric benzyl butyl-tolyl hydrogen siloxane or ethyl hydrogen siloxanes.  The alcohols may be replaced by acids, e.g. fatty acids or water and benzene or benzine may be employed as solvents. Equivalent results are obtained when dibutyl tin dilaurate in examples 1 to 5 is replaced by dibutyl tin dimaleinate, phenyl mercury acetate, iron octoate, copper stearate, titanium butylate, nickel octoate, zirconium oxychloride, aluminium chloride or acetyl acetonate or isoproplate, zinc stearate or lead acetate.ALSO:In a process for reducing reducible chemical substances which are soluble in organic solvents, by reducing certain metal compounds to the metals, the substance to be reduced is reacted with an organosilicon compound containing at least some hydrogen atoms bonded to silicon atoms by an H-Si bond in the presence of an organic solvent or diluent medium and as catalyst a metallic compound other than chloroplatinic acid which is soluble in the organic solvent or diluent.  There may be present in the reaction mixture a compound containing an active hydrogen atom.  Suitable organosilicon compounds including organosilanes and organosiloxanes for use in the process are listed.  Examples of compounds containing active hydrogen mentioned are water, alcohols and acids.  Metal compounds for use as catalysts include organo metallic compounds and metal salts of organic acids.  In examples, metallic tin is obtained as by-product when linear methyl hydrogen polysiloxane in ethyl alcohol is added to a boiling mixture of nitrobenzene, ethyl hexanol and dibutyl tin dilaurate (3); titanium is obtained by reacting titanic acid butyl ester with methyl hydrogen polysiloxane in benzene solution (7); tin is obtained by reacting tin tetraricinoleate in methanol solution with linear methyl hydrogenpolysiloxane (9); tin is obtained by reacting dibutyl tin dilaurate with methyl hydrogen polysiloxane (10).