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July 3o, 194s. G. A. DALIN PROCESS OF MAKING ORGANO 2,405,019 SILICON COMPOUNDS CONTAINING A C~SI BOND Filed Oct. 5, 1943 Patented‘July 30, 191% 2,405,019 . UNITED A.STATES PATENT 'oFElcE 2,405,019 PROCESS OF MAKING ORGANO-SILICON COMPOUNDS CONTAINING A C-Sl BOND 'George A. Daun. nemers. Conn., assig‘nor to Flax Corporation, Hartfor ,‘Conn., a corporation of Delaware Y Application october s. 19'43. sensi No. sesgos-i 5 Claims. (Cl. 260-807) 'I'his invention relates to the synthesis of of time, and, in fact, probably react at every organo~silicon compounds containing a C-Si bond. collision. It has particular relation to organic substituted Activation can be effected in various ways, such silicon halides, that is, silicon halides in which as by the use of high temperature, electrical dis from one to three halide atoms are replaced by a corresponding number of organic radicals or groups and having the general form charge, in the presence oi’ one or more of the reac tants. ultra-violet light, and by the introduction of rapidly moving particles, such as alpha and beta particles, and hydrogen and chlorine atoms. I have also found that the rate of reaction can where R is an organic radical or group, a carbon atom of which is bonded directly to Si. X is a 10 be increased by the use of suitable catalysts in the reaction zone. Examples of catalysts are silver, halide bonded to Si, and a=1 to 3. iron, copper in the form of metals or oxides ad Such compounds are useful as intermediates sorbed in activated carbon. for -the synthesis of various products, such as A preferred form of the invention comprises silicon resins, and in making heat transfer liquids activating vapors of a hydrocarbon and of a sili impregnants, adhesives, coatings, insulation ma con halide by means of thermal energy. To ac terials and lubricants. complish this the vapors may be passed through The general object is to provide a novel process a suitably heated furnace such as an electrically of making such compounds more cheaply, and eiilciently, and safely than they can be made by s heated quartz tube. To increase the total con 20 version, the unreacted portion of the materials prior processes. may be recirculated. The vapors may be suit Heretofore these compounds have been made ably replenished with the reactants in order to principally by the well-known Grignard reaction. keep the composition of the reaction mixture In this reaction, organo-magnesium halides in constant. The condensate may then be sub ether solution must first be prepared, which are subsequentlyfadded to silicon tetrachloride. Very 25 Jected to fractional distillation to separate the organo-_silicon reaction products. ~ careful control of the temperature and reaction velocity is required. Several illtrations must be t If an evaporative process is used, the concen trations of the _reactants are selected to give the carried out under conditions requiring the exclu sion of O2. CO2 and H2O, followed by vacuum dis 30 proper ratio thereof in the vapor phase with due allowance for differences in vapor pressure. The tillation of the complex mixture of reaction prod ucts. rate of ilow of the reactants, the pressure in the apparatus and the temperature of the hot tube The principal disadvantages in this process when carried out on a commercial scale are: or furnace, as Well as the composition of the 1. Relatively high cost of the alkyl and aryl 35 reaction mixture, are controlled toregulate or halides. , inñuence the reaction. The reaction can be car ried out at reduced pressure in which case air 2. Diñlculties and dansers in handling the large should be removed and prevented from entering quantities of extremely reactive, corrosive and the apparatus. The reaction zone may be heated _ The Grignard reaction also is undesirable as 40 to a temperature of approximately 840° C. to 1060° C. or higher. Lowertemperatures may be the basis of a commercial process because it can used when a catalyst is employed. be run only as a batch process. In order to conduct the reactants through the I have discovered that if suitable hydrocarbons apparatus and to insure that air and oxygen will and silicon halides are passed in the vapor phase through a. zone wherein they are activated, the 45 be excluded, I prefer to use an inert carrier gas fo'r the reactants'. Nitrogen is suitable for this synthesis of organo~silicon compounds, in which purpose. The carrier gas should be freed o1' oxy carbon is bonded directly to silicon, occurs. 'I'his gen and moisture bypassing it through a suit activation consists in imparting energy as rota inñammable materials. tional,> vibrational, electronic or translational able purifying and drying train before admitting energy to one or more oi the reactants, and thus 50 it‘to the apparatus. The apparatus should be prepared before starting operations by passing increasing the concentration of reactive mole cules. y the carrier gas alone or with reactants there If sumcient energy is imparted, dissociation ' takes place, with the formation of free radicals i in the Vapor phase. These fragments are so reac tive that they can exist for only very short periods through. This may best be done before the reac tion chamber is heated up. All joints and con nections must be air-tight and so constructed that 55 the reactants will not be contaminated by foreign matter such as lubricants. 9,406,019 ` f 4 stitution to form a mixed compound, such as I have employed three principal methods to pass th’e- reactants throughthe reaction sys phenyl methyl silicon dihalide. The release of methyl groups from aromatic compounds typi tem. Figure 1 shows schematically, the sequence of' operations involved in 'any of these methods. provisions for variation in these operations be ing indicated. iled by toluene may be facilitated by the presence of chlorine in the ortho or para positions. An examplefoi such compounds is ortho-, or para chlorotoluene. ‘ Hydrocarbons containing tertiary carbon atomsÑ . Method No. 1.-Vacuum- transfer may be used in'v carrying out my invention to The raw materials, ii liquid, are placed in the reservoir, or reservoirs, which may be heated. 10 take advantage o! the high degree of reactivityj The pump is connected into the line and started 4 oi hydrogen atoms bonded to such carbon atoms. up, evacuating the system back to the reservoir. ' Examples of such hydrocarbons are isobutane and cymene. The contents of the reservoir are permitted to To form- methyl silicon halides, methane and evaporate and to pass (with or without pre heating) into the reaction chamber, through the 15 ethane as well as other volatile paraiiln hydro carbons may be used, particularly highly condensing system and into the separating sys branched hydrocarbons which have more methyl groups. Methane, for example, dissociates .to keeping the composition of the liquid in the form methyl groups and hydrogen atoms. Each reservoir such that, according to well-known principles of evaporation, the composition oi the 20 ethane -molecule dissociates into two methyl groups:I Methane or ethane may also be used vapor will be that desired. to form >mixed compounds.~ Thus. the silicon Method No. 1-A tetrahalide ilrst may be reacted with methane and then with benzene to form phenyl methyl _ In order to increase the rate oivevaporation silicon halide or these reactions may be carried and, i! desired, to dilute the reactants, a 'carrier out simultaneously to obtain the same product. gas is passed through the contents of the reser > The preferred silicon Itetrahalide employed as voir. thus becoming laden with'the vapors of the tem. Suitable arrangements can be made for reactants. ’ areactant is silicon tetrachloride. ~ ‘MethodîNd Zn-Carrier aas An ihert carrier gas, such as nitrogen, is passed through the reservoir. The system may be main tained at any pressure from atmospheric up to that at which the carrier gas is supplied. The . Benzene is preferred to form phenyl substituted silicon com 30 pounds. Also, it is preferred to use a hot tube as the means for activating the reactants. In forming aryl-silicon compounds from ben zene and silicon tetrahalide according to my use of a vacuum pump is not'required. 35 novel process valuable by-products, such as di phenyl. also may be formed. The amount oi di Method No. 3.-Fzasn boiler a phenyl formed may be increased -by increasing The reactants are pumped into a ñash boiler, the ratio of benzene to silicon tetrahalide in the and being given no opportunity tocondense be reactant mixture. fore reaching the reaction zone must pass 40 through it in the vapor phase. 250 ml. of a solution containing silicon tetra chloride and benzene in the proportions of 100 to 130 parts by weight was placed in an evaporator Method No. sea-Flash boiler wimÍ carrier gas The ñash boiler method may be used in com bination with a carrier gas. l _ In the event that the hydrocarbon is a gas, it may be admitted to the reaction chamber, with or without preheating. Example I 45 havin-g air-tight connection with an electrically heated quartz tube. The tube was heated to 840° C. and nitrogen passed through the solution at the rate of about 1/_2 liter per minute in accord The drawing indicates provision for irradiat ing the chamber with ultra-violet light, heating ance with Method No. 2 described above. excited particles which may be used separately rated and passed through the tube. The reaction or in combination. products were collected in a dry-ice trap and then The system was maintained at atmospheric pressure. the chamber, and for the admission of various 50 In about 61/2 hours all the solution ywas evapo ` Although the drawing indicates apparatus for distilled up to 85° C. at atmospheric pressure. practicing all of the methods described above, it The residue was distilled at a pressure of approx will be understood that variations and changes 55l imately 19 m. m. and'fractions were collected as may be made in the apparatus indicated in the follows: 11o-130° C., 30% of distillate collected; drawing without departing from the invention. 130-140°, 10% of distillate collected; 140-170" C., i The conversion may be increased by connect 30% collected: and 17o-175° C., 30% was col ing a separating system' (scrubbing towers,` still, lected. The 'distillation range of this last frac# etc.) between the discharge end of the reaction 60 tion at thegpressure indicated corresponds closely to that~of diphenylsilicondichloride. The follow chamber and its inlet end so that unreacted' vapors or gas may be separated from the end ing is a comparison of an analysis of this fraction products and passed again through the zone of with the calculated composition of diphenylsili reaction. The converted materials may be drawn` condichloride. 65 out oi the separating system and fractionated. The hydrocarbon to be used is selected accord Diphenylsili Fraction at condiohlorido ing to the organic radical or radicals to be sub 17o-175° O. calcmmd stituted for the halide atoms oi the silicon tetra halide. To effect aryl substitution an aryl com pound is used. Thus benzene may be used to effect phenyl substitution.> Other examples of aryl compounds are naphthalene, anthracene, iiuorene, phenanthrene, indene and diphenyl. Aralkyl compounds may also be used. Thus, toluene may effect both phenyl and methyl sub- ~ Percent Percent 3. 28. l1. 56. 'â a F .. lI ..00. :sses: .97 0 .00 9 asna. 5 2,405,019 Eœample II , 43.7 grams of silicon tetrachloride and 56.3 grams of benzene (which evaporates to give a ra tio of approximately 1:1 in mols in the vapor phase) were placed in an evaporator and con nected to a reservoir containing 68.5 grams of silicon tetrachloride and 31.5 grams of benzene for replacement of the evaporated reactants. Using the technique of Method No. 1, the react ants were evaporated and passed through the quartz tube at 850° C., at a pressure of approxi mately 50 mm. The reaction products were con Example VI 700 ml. of S1014 and approximately 8 cubic feet of cthane were passed through a stainless steel tube at 1030° C. in 49 minutes, using Method No. 3A. 'I'he tube was packed with a catalyst similar to that in Example V. The products were col lected in brine-cooled xylene. Fractiona1 distillation yielded a. fraction, boil ing between 32.4° C. and 56.0° C., and a second fraction boiling between 65.3° C. and 75.0° C., as well as'unchanged silicon tetrachloride. The ñrst fraction appeared to consist of te densed and distilled up to 88° C. at atmospheric pressure to remove traces of silicon tetrachloride and nearly all the benzene. >The residue solidi tramethyl-silicane, trimethylsiliconmonochloride ñed on cooling and was identified as a mixture. of methylsilicon trichloride and dimethylsilicondi chloride. andV silicon tetrachloride. The higher boiling fraction on analysis proved to be a. mixture of aryl substituted silicon halides and diphenyl. From the foregoing it will be seen that I have Example III provided a. novel process whereby organo-silicon The procedure of Example II was repeated at 20 compounds may easily and continuously be pro a pressure of 45 to 55 mm. which was found to lbe the optimum range for fog formation in the hot tube. The temperature of the tube was 960° C. The fog was white at 45 mm. and brown at 55 mm, The optimum pressure varied considerably de ending upon the stage of reaction. After ev porating and passing about 250 ml. of solution through the tube, the collected condensate was distilled up to 85° C. Following this, three frac tions were collected at a pressure of 45 mm.: A at 30 duced from raw materials which are plentiful and of low cost. Having thus described my invention. what I desire to claim and secure by Letters Patent is: 1. A process for the preparation of organo silicon compounds which comprises reacting an inorganic silicon halide with a hydrocarbon While both reactants are in the vapor phase at a tem perature of not less than approximately 840° C., condensing the reaction products. and separating 240°-260° C.; B at 260°-360° C.; and C at 360° organic substituted silicon halide from such re 480° C. (all temperatures uncorrected). Quanti action products. tative analysis of fraction C veriñed the presence 2. A process for the preparation of organo of phenyl substituted silicon chloride compounds silicon compounds which comprises reacting an in and by-products, such as diphenyl. 35 organic silicon halide with a hydrocarbon while both reactants are in the vapor phase at a tem Example IV perature of from 840° C. to 1060° C., condensing 90 ml. of benzene and 90 ml. of silicon tetra the reaction products, and separating organic sub chloride were evaporated and the vapor mixture stituted silicon halide from such reaction prod passed by evaporation through the hot tube once ucts. . at 980° C. The condensate was distilled to re move silicon tetrachloride and 20 ml. of toluene added and removed by distillation leaving a resi 3. A process for the preparation of organo silicon compounds which comprises reacting an inorganic silicon halide with a hydrocarbon con due which solidified. Quantitative analysis taining a tertiary carbon atom while both re showed that the main product was triphenyl 45 actants are in the vapor phase at a temperature siliconmonochloride. of from 840° C. to 1060° C., condensing the re Example V y action products, and separating organic sub stituted silicon halide from such reaction prod 850 ml. of SiC14 and 5% cubic feet of methane ucts. were passed through a stainless steel tube at 960° 50 4. A process for the preparation of organo C. in 63 minutes. in accordance with Method No. silicon compounds which comprises reacting an 3A. « inorganic silicon halide with an aromatic hy The tube was packed with a catalyst prepared drocarbon while both reactants are in the vapor as follows: A ten per cent solution of ferric ammonium Ul u phase ata temperature of not less than ap proximately 840° C., condensing the reaction prod alum was prepared. Activated carbon in 4 mesh ucts, and separating organic substituted silicon granular form was soaked in this solution and halide from the reaction products. ammonia was added until strongly basic, The 5. A process for the preparation of organo carbon was washed by decantation until the wash ' water was neutral. The catalyst was dried at 60 silicon compounds which comprises reacting silicon tetrachloride with benzene while both re 110° C. for 16 hours and charged into the reac actants are in the vapor phase at a temperature tion tube.l In bringing the tube to 960° C., a of from 840° C. to 1060° C., and separating the small amount of water was evolved and removed. organo-silicon products resulting from the re The products of the reaction were absorbed in xylene and fractionated. .A fraction distilling be 65 action. tween 61° and 69° C. was collected and analyzed. GEORGE A. DALIN. It proved to be fairly pure methylsilicontrichlo- . ride.