Patent GB-681527-A (GB)
Title: A process for the manufacture of organosilicon compounds
IPC: C07F7/12
Filed: 1951-01-18
Abstract: Organo silicon polyesters are obtained by the reaction of phthalic anhydride and a small amount of glycerine with the polyhydric alcohols obtained by the hydrolysis of polyacetoxymethyl silanes (the polyacetoxymethyl silanes are obtained by the reaction of poly-(chloromethyl) silanes-for preparation (see Group IV (b)), with potassium acetate).ALSO:Poly-(chloromethyl)-silanes are prepared by continuously charging into a reaction zone chlorine and a compound of the general formula (CH3)a(CH2Cl)bSiCl4-a-b, wherein a has a value from 1 to 3, b has a value of from 1 to 2, and a+b has a value from 2 to 4, each inclusive, maintaining the reaction zone at a temperature between the boiling point of the compound of the above general formula and of the desired product, whereby poly-(chloromethyl)-silanes having a higher chlorine content than the chlorine content of the chloromethylmethylsilane reactant condense on formation, and are continuously removed from the reaction zone.  The reaction <PICT:0681527/IV (b)/1> <PICT:0681527/IV (b)/2> may be accelerated by exposure to light.  Suitable compounds which may be chlorinated are (CH3)3SiCH2Cl, (CH3)2(CH2Cl)SiCl, (CH3)2 (CH2Cl)2Si, CH3(CH2Cl)SiCl2 and CH3(CH2Cl)2 SiCl.  In the examples the following compounds are prepared: CH3SiCl(CH2Cl)2, CH3SiCl(CH2Cl) (CHCl2) and (CH3)2Si(CH2Cl)2 together with the following compounds formed as impurities (CH3)2SiCl(CHCl2), (CH3)2SiCl(CCl3), and (CH3)3 SiCHCl2. Fig. 1 illustrates an apparatus for carrying out the above process, and comprises reactant line 1 leading into the bottom of chlorinator 2 provided with heat exchanger 3.  The vapours of the reactant rise from liquid level 4, through trap-out plate 9 and are chlorinated with chlorine introduced by line 5 and diffuser 6.  Heat exchanger 7 condenses silane vapour from effluent hydrogen chloride which is removed by line 8.  The chlorinated product boils below the temperature of the chlorinator and is collected on trap-out plate 9 and is removed through line 10.  Lights 11 are located in the wall of the chlorinator to accelerate the reaction.  In an alternative apparatus, Fig. 2, the reactants are maintained in the vapour phase in chlorinator 20 which communicates with a distillation column 21. The top zone of the chlorinator is provided with heat exchanger 22, and is separated from the reaction zone below by trap-out plate 23 for removing liquid phase reactant via drain 26.  Sloping plate 24 serves to drain liquid reaction product into the collector section of the chlorinator.  The reactant is introduced at 25 between plates 23 and 24 and vaporizer 27 vaporizes liquid reactant collected in 26 which is then passed through line 28.  Chlorine is introduced through diffuser 29 and the reaction is accelerated with lights 30.  The fractionator 21 is of the conventional type for separating reaction product introduced by line 31 from the bottom of chlorinator 20. Polyacetoxymethyl- and polyhydroxymethylsilanes are obtained by reacting the products of the above process with potassium acetate and, if required, hydrolysing the polyacetoxymethyl silanes thus formed.