Title of Invention	PROCESS FOR THE PREPARATION OF (MERCAPTOORGANYL ) -ALKOXYSILANES
Abstract	Process for the preparation of (mercaptoorganyl)- alkoxysilanes wherein alkali metal sulfide is reacted with a mixture of (haloorganyl) alkoxysilane and (haloorganyl) halosilane in an alcohol with the exclusion of air, at temperatures of from 0 to 180°C and under elevated pressure of 0.1 to 10 bar above normal pressure.

Full Text

The invention relates to a process for the preparation of (mercaptoorganyl)alkoxysilanes. It is known to prepare mercaptoalkylsilanes in a one- step reaction by reacting suitable (haloorganyl)alkoxy- silane compounds with thiourea and ammonia (DE AS 2035619). This method has the disadvantage that long batch times (more than 24 hours) are required to achieve economically acceptable conversion rates. The yields that are achievable when using this procedure are variable and reach values of only from 75 to 80 %, based on the conversion of (haloorganyl)alkoxysilane compound used. In addition, guanidine hydrochloride is formed in this procedure, the separation and disposal of which necessitate additional expenditure. Also known are processes for the preparation of mercaptoalkylsilanes in which the reaction to form mercaptosilanes is carried out by hydrogenation of thiopropionic acid amide silanes under pressure (EP 0018094.) or by hydrogenation of cyanoalkylsilane compounds in the presence of elemental sulfur or hydrogen sulfide (US-PS 4012403). Both processes have the disadvantage that the yield is poor. US 3,849,471 discloses the preparation of mercapto- silanes by reaction of the appropriate (haloorganyl)- alkoxysilane compounds with hydrogen sulfide in the presence of ethylenediamine and large amounts of heavy metal sulfides. A disadvantage of this process is the formation of various secondary products and the separation thereof. It is also known that the process of US 3,849,471 can be improved by reacting the starting silanes with hydrogen sulfide not in the presence of diamines but in the presence of ammonia, primary, secondary or tertiary amines, optionally additionally in the presence of polar, protic or aprotic media (US 4,082,790). It is disadvantageous in this procedure that, in order to achieve the required reaction temperatures for the reaction of the reactants, the reactions must be carried out in high-pressure autoclaves. If the reactions are carried out in the absence of polar media, uneconomically long reaction times have to be accepted in order to achieve acceptable conversion rates. Moreover, the metered addition and handling of highly toxic H2S on an industrial scale is undesirable, expensive and associated with a high level of safety precautions. From GB 1 102 251 there is known the reaction of alkali hydrogen sulfides with (haloalkyl)alkoxysilanes in a methanolic medium to form the corresponding mercapto- silanes. This procedure has the disadvantage that an extraordinarily long reaction time (96 hours) is required to achieve high conversion rates and the yield achieved thereby is unsatisfactory. It is known to prepare (mercaptoalkyl)alkoxysilanes by reacting alkali hydrogen sulfide with suitable (halo- alkyl) alkoxysi lanes in the presence of a 10-100 % molar excess of H2S (US 5,840,952). On an industrial scale, this process has the disadvantage that highly toxic H2S must be metered in and handled. The known process must be carried out in 2 steps, leading to a fall in the space-time yield of the process. It is also known to prepare (mercaptoalkyl)alkoxy- silanes by reacting (haloalkyl)alkoxysilanes with alkali hydrogen sulfide (NaSH) in polar, aprotic solvents (EP 0 471 164). The disadvantage of this process is that large amounts, at least 50 vol.%, of solvent are used and, for example in the case of dimethylformamide, this is toxic. In addition, the later working-up of the reaction products by distillation and their purification are made more difficult by the high boiling point of dimethylformamide. The object of the invention is to provide a process for the preparation of (mercaptoorganyl)alkoxysilanes in which no gaseous raw materials are used and high space- time yields in the reaction of the (haloorganyl)silanes are achieved specifically while avoiding the metered addition and handling of highly toxic hydrogen sulfide or toxic dimethylformamide. The invention provides a process for the preparation of (mercaptoorganyl)alkoxysilanes which is characterised in that alkali metal sulfide is reacted with a mixture of (haloorganyl)alkoxysilane and (haloorganyl)halo- silane in an alcohol with the exclusion of air and under elevated pressure. (Mercaptoorganyl)alkoxysilanes may be compounds of the general formula I wherein the substituents R are identical or different and are a C1-C8 alkyl, preferably CH3, alkenyl, aryl or aralkyl group or a group OR' , the substituents R' are identical or different and are a C1-C24, preferably C1-C4 or C12-C18, branched or unbranched monovalent alkyl or alkenyl group, aryl group, aralkyl group, R' is a branched or unbranched, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic/aromatic divalent C1-C30 hydrocarbon group which is optionally substituted by F, Cl, Br, I, NH2 or NHR'. x is 1-3. For x = 1 R' may represent -CH2-, -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH(CH3)-, -CH2CH(CH3) - , -CH (CH3) CH2-, -C(CH3)2-, -CH(C2H5)-. -CH2CH2CH(CH3)-, -CH2CH (CH3) CH2- or For x = 2 R' may represent CH, -CH-CH2, -CH2-CH, C-CH3, -CH-CH2-CH2, -CH-CH-CH3 or -CH2-CH-CH2. (Mercaptoorganyl)alkoxysilanes of the general formula I may be: 3-mercaptopropyl(trimethoxysilane), 3-mercaptopropyl(triethoxysilane), 3-mercaptopropyl(diethoxymethoxysilane), 3-mercaptopropyl(tripropoxysilane), 3-mercaptopropyl(dipropoxymethoxysilane), 3-mercaptopropyl(tridodecanoxysilane), 3-mercaptopropyl(tritetradecanoxysilane), 3-mercaptopropyl(trihexadecanoxysilane), 3-mercaptopropyl(trioctadecanoxysilane), 3-mercaptopropyl(didodecanoxy)tetradecanoxysilane, 3-mercaptopropyl(dodecanoxy)tetradecanoxy(hexa- decanoxy)silane 3-mercaptopropyl(dimethoxymethylsilane), 3-mercaptopropyl(methoxydimethylsilane), 3-mercaptopropyl(diethoxymethylsilane), 3-mercaptopropyl(ethoxydimethylsilane), 3-mercaptopropyl (dipropoxymethylsilane) , 3-mercaptopropyl (propoxydimethylsilane) , 3-mercaptopropyl (diisopropoxymethylsilane) , 3-mercaptopropyl(isopropoxydimethylsilane), 3-mercaptopropyl(dibutoxymethylsilane) , 3-mercaptopropyl(butoxydimethylsilane), 3-mercaptopropyl (diisobutoxymethylsilane) , 3-mercaptopropyl(isobutoxydimethylsilane), 3-mercaptopropyl(didodecanoxymethylsilane), 3-mercaptopropyl(dodecanoxydimethylsilane), 3-mercaptopropyl(ditetradecanoxymethylsilane), 3-mercaptopropyl(tetradecanoxydimethylsilane), 2-mercaptoethyl(trimethoxysilane), 2-mercaptoethyl(triethoxysilane), 2-mercaptoethyl(diethoxymethoxysilane), 2-mercaptoethyl(tripropoxysilane), 2-mercaptoethyl(dipropoxymethoxysilane), 2-mercaptoethyl(tridodecanoxysilane), 2-mercaptoethyl(tritetradecanoxysilane), 2-mercaptoethyl(trihexadecanoxysilane), 2-mercaptoethyl(trioctadecanoxysilane), 2-mercaptoethyl(didodecanoxy)tetradecanoxysilane, 2-mercaptoethyl(dodecanoxy)tetradecanoxy(hexadecanoxy)- silane, 2-mercaptoethyl(dimethoxymethylsilane), 2-mercaptoethyl(methoxydimethylsilane), 2-mercaptoethyl(diethoxymethylsilane), 2-mercaptoethyl(ethoxydimethylsilane), 1-mercaptomethyl(trimethoxysilane), 1-mercaptomethyl(triethoxysilane), 1-mercaptomethyl(diethoxymethoxysilane), 1-mercaptomethyl(dipropoxymethoxysilane), 1-mercaptomethyl(tripropoxysilane), 1-mercaptomethyl(trimethoxysilane), 1-mercaptomethyl(dimethoxymethylsilane), 1-mercaptomethyl(methoxydimethylsilane) , 1-mercaptomethyl(diethoxymethylsilane), 1-mercaptomethyl(ethoxydimethylsilane) , 1, 3-dimercaptopropyl(trimethoxysilane), 1,3-dimercaptopropyl(triethoxysilane), 1, 3-dimercaptopropyl(tripropoxysilane), 1, 3-dimercaptopropyl(tridodecanoxysilane), 1, 3-dimercaptopropyl(tritetradecanoxysilane), 1, 3-dimercaptopropyl(trihexadecanoxysilane), 2,3-dimercaptopropyl(trimethoxysilane), 2,3-dimercaptopropyl(triethoxysilane), 2,3-dimercaptopropyl(tripropoxysilane), 2,3-dimercaptopropyl(tridodecanoxysilane), 2,3-dimercaptopropyl(tritetradecanoxysilane), 2,3-dimercaptopropyl(trihexadecanoxysilane), 3-mercaptobutyl(trimethoxysilane), 3-mercaptobutyl(triethoxysilane), 3-mercaptobutyl(diethoxymethoxysilane), 3-mercaptobutyl(tripropoxysilane), 3-mercaptobutyl(dipropoxymethoxysilane), 3-mercaptobutyl(dimethoxymethylsilane), 3-mercaptobutyl(diethoxymethylsilane), 3-mercaptobutyl(dimethylmethoxysilane), 3-mercaptobutyl(dimethylethoxysilane), 3-mercaptobutyl(tridodecanoxysilane), 3-mercaptobutyl(tritetradecanoxysilane), 3-mercaptobutyl(trihexadecanoxysilane), 3-mercaptobutyl(didodecanoxy)tetradecanoxysilane or 3-mercaptobutyl(dodecanoxy)tetradecanoxy(hexadecanoxy)- silane. In the process for the preparation of (mercapto- organyl)alkoxysilanes there may be formed compounds of the general formula I or mixtures of compounds of the general formula I. There may be used as (haloorganyl) alkoxysilanes compounds of the general formula II wherein x, R, R' and R' are as defined above and Hal is chlorine, bromine, fluorine or iodine. There may preferably be used as (haloorganyl)alkoxy- silanes 3-chlorobutyl(triethoxysilane), 3-chlorobutyl(trimethoxysilane), 3-chlorobutyl(diethoxymethoxysilane), 3-chloropropyl(triethoxysilane), 3-chloropropyl(trimethoxysilane), 3-chloropropyl(diethoxymethoxysilane), 2-chloroethyl(triethoxysilane), 2-chloroethyl(trimethoxysilane), 2-chloroethyl(diethoxymethoxysilane), 1-chloromethyl(triethoxysilane), 1-chloromethyl(trimethoxysilane), 1-chloromethyl(diethoxymethoxysilane), 3-chloropropyl(diethoxymethylsilane), 3-chloropropyl(dimethoxymethylsilane), 2-chloroethyl(diethoxymethylsilane), 2-chloroethyl(dimethoxymethylsilane), 1-chloromethyl(diethoxymethylsilane), 1-chloromethyl(dimethoxymethylsilane), 3-chloropropyl(ethoxydimethylsilane), 3-chloropropyl(methoxydimethylsilane), 2-chloroethyl(ethoxydimethylsilane), 2-chloroethyl(methoxydimethylsilane), 1-chloromethyl(ethoxydimethylsilane) or 1-chloromethyl(methoxydimethylsilane). The (haloorganyl)alkoxysilane may be a (haloorganyl)- alkoxysilane of the general formula II or a mixture of (haloorganyl)alkoxysilanes of the general formula II. There may be used as (haloorganyl)halosilanes compounds of the general formula III wherein x, Hal, R and R' are as defined above and the substituents R'', independently of one another, are R or Hal. There may preferably be used as (haloorganyl)halo- si lanes 3-chlorobutyl(trichlorosilane), 3-chloropropyl(trichlorosilane), 2-chloroethyl(trichlorosilane), 1-chloromethyl(trichlorosilane), 3-chlorobutyl(dichloromethoxysilane), 3-chloropropyl(dichloromethoxysilane), 2-chloroethyl(dichloromethoxysilane), 1-chloromethyl(dichloromethoxysilane), 3-chlorobutyl(dichloroethoxysilane), 3-chloropropyl(dichloroethoxysilane), 2-chloroethyl(dichloroethoxysilane), 1-chloromethyl(dichloroethoxysilane), 3-chlorobutyl(chlorodiethoxysilane), 3-chloropropyl(chlorodiethoxysilane), 2-chloroethyl(chlorodiethoxysilane), 1-chloromethyl(chlorodiethoxysilane), 3-chlorobutyl(chlorodimethoxysilane), 3-chloropropyl(chlorodimethoxysilane), 2-chloroethyl(chlorodimethoxysilane), 1-chloromethyl(chlorodimethoxysilane), 3-chlorobutyl(dichloromethylsilane), 3-chloropropyl(dichloromethylsilane), 2-chloroethyl(dichloromethylsilane), 1-chloromethyl(dichloromethylsilane), 3-chlorobutyl(chloro-)(methyl-)methoxysilane) , 3-chloropropyl(chloro-)(methyl-}methoxysilane) , 2-chloroethyl(chloro-)(methyl-)methoxysilane), 1-chloromethyl(chloro-)(methyl-)methoxysilane), 3-chlorobutyl(chloro-)(methyl-)ethoxysilane), 3-chloropropyl(chloro-)(methyl-)ethoxysilane), 2-chloroethyl(chloro-)(methyl-)ethoxysilane), 1-chloromethyl(chloro-)(methyl-)ethoxysilane), 3-chlorobutyl(chlorodimethylsilane), 3-chloropropyl(chlorodimethylsilane), 2-chloroethyl(chlorodimethylsilane) or 1-chloromethyl(chlorodimethylsilane). The (haloorganyl)halosilane may be a (haloorganyl)halo- silane of the general formula III or a mixture of (haloorganyl)halosilanes of the general formula III. (Mercaptoorganyl)alkoxysilanes of the general formula I can be prepared by reacting alkali metal sulfide with a mixture of (haloorganyl)alkoxysilane of the general formula II and (haloorganyl)halosilane of the general formula III in. an alcohol with the exclusion of air and under elevated pressure. The composition of mixtures of compounds of the general formula I can actively be influenced in a targeted manner by the choice of the (haloorganyl)alkoxysilanes and (haloorganyl)halosilanes. The quality and nature of the composition of the mixture of (haloorganyl)alkoxysilane and (haloorganyl)- halosilane can be evaluated on the basis of the amount and nature of the hydrolysable Si-Hal bonds contained in the mixture. The amount of hydrolysable Si-Hal bonds is determined by the following process: 80 ml of ethanol and 10 ml of acetic acid are added to not more than 20 g of the sample in a 150 ml glass beaker. The halide content is titrated potentiographically with silver nitrate solution (c(AgNO3)=0.01 mol./l). The advantageous molar ratios of the mixtures of (haloorganyl)alkoxysilanes and (haloorganyl)halosilanes can depend, inter alia, on the number of Si-halogen functions of the chosen (haloorganyl)halosilanes. (Haloorganyl)alkoxysilanes and (haloorganyl)halosilanes can be used in a molar ratio of from 0.001:1 to 2:1. In the reaction of 3-chloropropyl(trimethoxysilane) or 3-chloropropyl(triethoxysilane) and 3-chloropropyl- (trichlorosilane) , for example, a molar ratio of from 2:1 to 2:1.5 can preferably be used, particularly preferably a molar ratio of from 2:1 to 2:1.25. In the reaction of 3-chloropropyl(methyl- dimethoxysilane) or 3-chloropropyl(methyldiethoxy- silane) and 3-chloropropyl(methyldichlorosilane), for example, a molar ratio of from 1:1 to 1:1.25 can preferably be used, particularly preferably a molar ratio of from 1:1 to 1:1.15. In the reaction of 3-chloropropyl(dimethylmethoxy- silane) or 3-chloropropyl(dimethylethoxysilane) and 3- chloropropyl(dimethylchlorosilane), for example, a molar ratio of from 0.001:1 to 0.05:1 can preferably be used. The mixture of the appropriate (haloorganyl)alkoxy- silane and (haloorganyl)halosilane used for the process can be prepared before the addition of the alkali sulfide, depending on the apparatus used and the desired effects, for example selectivity of the reaction, duration of the reaction, reactor coating, reactor material or process sequence. Alkali metal sulfides may be dialkali metal sulfides Me2S. There may be used as dialkali metal sulfides dilithium sulfide (Li2S) , disodium sulfide (Na2S) , dipotassium sulfide (K2S) and dicaesium sulfide (Cs2S) . The molar amount of alkali metal sulfide used can exceed the molar amount of the (haloorganyl)halosilane that is used by from 1 % to 200 %, preferably by from 1 % to 150 %, particularly preferably by from 1 % to 110 %. The molar ratio of hydrolysable silicon-halogen functions, in the mixtures of (haloorganyl)alkoxysilane and (haloorganyl)halosilane, to alkali metal sulfide (Me2S) may be from 1:0.51 to 1:1.2, preferably from 1:0.6 to 1:1.15, particularly preferably from 1:0.75 to 1:1.05. It is possible to mix the (haloorganyl)alkoxysilane and (haloorganyl)halosilane with one another in any desired sequence and manner, at any desired temperature and for any desired duration, and only then to add the alcohol and alkali sulfide, together or in succession. It is possible to mix the (haloorganyl)halosilane, alkali sulfide and alcohol with one another in any desired sequence and manner, at any desired temperature and for any desired duration, and only then to add the (haloorganyl)alkoxysilane. It is possible to mix the (haloorganyl)alkoxysilane, alkali sulfide and alcohol with one another in any desired sequence and manner, at any desired temperature and for any desired duration, and only then to add the (haloorganyl)halosilane. There may be used as the alcohol primary, secondary or tertiary alcohols having from 1 to 24, preferably from 1 to 6, particularly preferably from 1 to 4, carbon atoms. There may be used as primary, secondary or tertiary alcohols methanol, ethanol, n-propanol, isopropanol, isobutanol or n-butanol. The amount of alcohol may be at least 100 vol.%, preferably from 250 to 1000 vol.%, particularly preferably from 500 to 1000 vol.%, of the silane components used. Polar, protic, aprotic, basic or acidic additives may be added to the reaction mixture at the beginning of the reaction and/or during the reaction and/or at the end of the reaction. Under elevated pressure may be understood to mean an excess pressure of from 0.1 to 10 bar, preferably from 1 to 7 bar, above normal pressure. The reaction can take place at temperatures of from 0 to 180°C, preferably from 50 to 150°C, particularly preferably from 70 to 120°C. The optimum reaction temperature in terms of the yield of target product and utilisation of the reaction volume can vary in dependence on the structure of the (haloorganyl)alkoxysilane, (haloorganyl)halosilane and alcohol used. In the case of reactions in methanol, for example, a reaction temperature of from 60 to 95°C may be advantageous with regard to reaction times, amount of secondary products and pressure build-up. In the case of reactions in ethanol, for example, a reaction temperature of from 75 to 120°C may be advantageous with regard to reaction times, amount of secondary products and pressure build-up. The reaction may be carried out in a closed container under a protecting gas. The reaction may be carried out in corrosion-resistant autoclaves, for example made of glass, Teflon, enamelled or coated steel, Hastelloy or tantalum. The amount of secondary products may be less than 20 mol.% as a result of the choice of reaction conditions. The process according to the invention has the advantages that it is possible to dispense with the use of highly toxic, gaseous substances, such as hydrogen sulfide, as sulfur donors. Instead, alkali metal sulfides, which are readily meterable solids (for example dried disodium sulfide), are used as sulfur donors. A further advantage of the process according to the invention is that the selectivity of the reaction can be increased merely by using a closed reaction vessel (autoclave or the like). A further advantage of the process according to the invention over known processes is the high conversions achieved with short batch times and at temperatures that are easily achieved industrially. Examples: Analysis by GC The analysis by GC is carried out on a HP 6890 (WLD) gas chromatograph having a DB5 column with a thickness of 0.53 mm and a film thickness of 1.5 µm. A thermal conductivity detector is used as the detector. The temperature program used contains the following cycles: - starting temperature 100°C - initial time 1 min. - 20°C/min to 280°C - maintain 280°C for 10 min. The retention times for the following components are: Example 1: 29.6 g of 3-chloropropyl(triethoxysilane) and 200 ml of ethanol are together introduced at -10°C into a stainless steel autoclave with a glass insert and a magnetic stirring device. 17.6 g of dried Na2S are added in several portions to the solution. 16.4 g of chloropropyl(trichlorosilane) are added and the autoclave is quickly closed. The autoclave and the substances therein are heated at 120°C for 180 minutes. During that time, the pressure rises to 3.2 bar above normal pressure. The autoclave is cooled to normal temperature and the suspension that has formed is removed. The solvent contained therein is reduced in a rotary evaporator and the precipitated solid is removed using a frit that has been rendered inert. 3 8.4 g of a clear, slightly brownish solution are obtained. Analysis of the reaction mixture by GC shows the following composition in percent by surface area:, Example 2: 24 g of 3-chloropropyl(triethoxysilane) and 150 ml of ethanol are together introduced at -10°C into a stainless steel autoclave with a glass insert and a magnetic stirring device. 12 g of dried Na2S are added in several portions to the solution. 10.6 g of 3- chloropropyl (trichlorosilane) are added and the autoclave is quickly closed. The autoclave and the substances therein are heated at 80°C for 180 minutes. The autoclave is cooled to normal temperature and the suspension that has formed is removed. The solvent contained therein is reduced in a rotary evaporator and the precipitated solid is removed using a frit that has been rendered inert. 29.2 g of a clear, slightly brownish solution are obtained. Analysis of the reaction mixture by GC shows the following composition in percent by surface area: Example 3: 40 g of 3-chloropropyl(triethoxysilane), 23 g of dried Na2S and 22 g of 3-chloropropyl(trichlorosilane) are together introduced at room temperature into an autoclave having a double-wall glass jacket and a stainless steel lid, and the autoclave is closed. 400 ml of ethanol are then pumped into the suspension at room temperature by means of a high-pressure pump. The mixture is heated to 80°C and maintained at 80°C for 5 hours. The mixture is then cooled to room temperature and analysed by gas chromatography. Analysis of the reaction mixture by GC shows the following composition in percent by weight: Based on the above-mentioned components, the selectivity is 89 % and the conversion is 90 %. Example 4: 40 g of 3-chloropropyl(triethoxysilane), 26.5 g of dried Na2S and 24.1 g of 3-chloropropyl(trichloro- silane) are together introduced at room temperature into an autoclave having a double-wall glass jacket and a stainless steel lid, and the autoclave is closed. The mixture is heated to 60°C. 400 ml of ethanol are then pumped into the suspension at 60°C by means of a high- pressure pump. The mixture is heated further to 80°C and maintained at 80°C for 5 hours. The mixture is then cooled to room temperature and analysed by gas chromatography. Analysis of the reaction mixture by GC shows the following composition in percent by weight: Based on the above-mentioned components, the selectivity is 82 % and the conversion is 97 %. Example 5: 50 g of dried Na2S and 650 ml of dry ethanol are introduced at room temperature into an autoclave having a double-wall glass jacket and a Hastelloy C22 lid + fittings (Buechi AG). The suspension is heated and stirred at 50°C for 20 minutes. 128.2 g of a silane mixture of 3-chloropropyl(diethoxy(chloro)silane), chloropropyl(ethoxy(dichloro)silane), chloropropyl- (trichlorosilane) and 3-chloropropyl(triethoxysilane) are added to the suspension by means of a compressed- air-operated burette. The silane mixture used is prepared by reacting 80 g of 3-chloropropyl(triethoxy- silane) and 48.2 g of 3-chloropropyl(trichlorosilane). A further 150 ml of ethanol are added to the suspension by means of the burette. The mixture is heated to 97-102°C, with stirring, and the temperature is maintained for 180 minutes. The mixture is then cooled to room temperature. A sample is removed and analysed by gas chromatography. Analysis of the reaction mixture by GC shows the following composition in percent by surface area: Based on the above-mentioned values, the conversion is >99 % and the selectivity of the reaction is 93 %. Example 6: 50 g of dried Na2S and 650 ml of dry ethanol are introduced at room temperature into an autoclave having a double-wall glass jacket and a Hastelloy C22 lid + fittings (Buechi AG) . The suspension is heated and stirred at 50°C for 20 minutes. A mixture of 80 g of 3- chloropropyl(triethoxysilane) and 48.2 g of 3-chloro- propyl(trichlorosilane) is added to the suspension by means of a compressed-air-operated burette. A further 150 ml of ethanol are added to the suspension by means of the burette. The mixture is heated to 95-100°C, with stirring, and the temperature is maintained for 180 minutes. The mixture is then cooled to room temperature. A sample is removed and analysed by gas chromatography. Analysis of the reaction mixture toy GC shows the following composition in percent by surface area: Based on the above-mentioned values, the conversion is 97 % and the selectivity of the reaction is 89.5 %. The reactor is emptied and flushed with a small amount of ethanol in order to remove any residues that have remained. The resulting suspension is filtered. The solid separated off is washed with 400 ml of n-pentane. The solution obtained is freed of volatile constituents at 200-600 mbar and 60-80°C using a rotary evaporator. The suspension obtained is mixed thoroughly with 200 ml of pentane and stored for 10 hours at 4-8°C. The precipitated solid is separated off by filtration and washed with 150 ml of pentane. The pentane is removed from the resulting clear solution using a rotary evaporator at 200-600 mbar and 60-80°C. 119.3 g of a colourless liquid are obtained. Combined analysis by GC, 1H-NMR and 29Si-NMR shows the following composition of the resulting product, in percent by weight: Based on the above-mentioned values, the conversion is 96 % and the selectivity of the reaction is 91 %. Example 7: 50 g of dried Na2S and 800 ml of dry ethanol are introduced at room temperature into an autoclave having a double-wall glass jacket and a Hastelloy C22 lid + fittings (Buechi AG). The suspension is heated and stirred at 50°C for 20 minutes. A mixture of 80 g of 3- chloropropyl(triethoxysilane) and 48.2 g of 3-chloro- propyl(trichlorosilane) is added to the suspension by means of a compressed-air-operated burette. A further 2 00 ml of ethanol are added to the suspension by means of the burette. The mixture is heated to 95-100°C, with stirring, and the temperature is maintained for 180 minutes. The mixture is then cooled to room temperature. A sample is removed and analysed by gas chromatography. Analysis of the reaction mixture by GC shows the following composition in percent by surface area: Based on the above-mentioned values, the conversion is 98 % and the selectivity of the reaction is 91 %. The reactor is emptied and flushed with a small amount of ethanol in order to remove any residues that have remained. The resulting suspension is filtered. The solid separated off is washed with 400 ml of n-pentane. The solution obtained is freed of volatile constituents at 200-600 mbar and 60-80°C using a rotary evaporator. The suspension obtained is mixed thoroughly with 200 ml of pentane and stored for 10 hours at 4-8°C. The precipitated solid is separated off by filtration and washed with 150 ml of pentane. The pentane is removed from the resulting clear solution using a rotary evaporator at 200-600 mbar and 60-80°C. 116.2 g of a colourless liquid are obtained. Combined analysis by GC, 1H-NMR and 29Si-NMR shows the following composition of the resulting product, in percent by weight: Based on the above-mentioned values, the conversion is 99 % and the selectivity of the reaction is 88 %. Example 8: 57.8 g of dried Na2S and 650 ml of dry ethanol are introduced at room temperature into an autoclave having a double-wall glass jacket and a Hastelloy C22 lid + fittings (Buechi AG). The suspension is heated and stirred at 50°C for 2 0 minutes. A mixture of 80.5 g of 3-chloropropyl(triethoxysilane) and 57.4 g of 3- chloropropyl(trichlorosilane) is added to the suspension by means of a compressed-air-operated burette. A further 150 ml of ethanol are added to the suspension by means of the burette. The mixture is heated to 110-115°C, with stirring, and the temperature is maintained for 12 0 minutes. The mixture is then cooled to room temperature. A sample is removed and analysed by gas chromatography. Analysis of the reaction mixture by GC shows the following composition in percent by surface area: Based on the above-mentioned values, the conversion is >99 % and the selectivity of the reaction is 91 %. The reactor is emptied and flushed with a small amount of ethanol in order to remove any residues that have remained. The resulting suspension is filtered. The solid separated off is washed with 400 ml of n-hexane. The solution obtained is freed of volatile constituents at 200-600 mbar and 60-80°C using a rotary evaporator. The suspension obtained is mixed thoroughly with 200 ml of hexane and stored for 10 hours at 4-8°C. The precipitated solid is separated off by filtration and washed with 150 ml of hexane. The hexane is removed from the resulting clear solution using a rotary evaporator at 200-600 mbar and 60-80°C. 121.3 g of a colourless liquid are obtained. Combined analysis by GC, 1H-NMR and 29Si-NMR gives the following composition of the resulting product, in percent by weight: Based on the above-mentioned values, the conversion is >99 % and the selectivity of the reaction is 88 %. Example 9: 57.7 g of dried Na2S and 800 ml of dry ethanol are introduced at room temperature into an autoclave having a double-wall glass jacket and a Hastelloy C22 lid + fittings (Buechi AG). The suspension is heated and stirred at 50°C for 20 minutes. A mixture of 80.5 g of 3-chloropropyl(triethoxysilane) and 57.4 g of 3- chloropropyl(trichlorosilane) is added to the suspension by means of a compressed-air-operated burette. A further 200 ml of ethanol are added to the suspension by means of the burette. The mixture is heated to 110-115°C, with stirring, and the temperature is maintained for 120 minutes. The mixture is then cooled to room temperature. A sample is removed and analysed by gas chromatography. Analysis of the reaction mixture by GC shows the following composition in percent by surface area: Based on the above-mentioned values, the conversion is >99 % and the selectivity of the reaction is 88 %. The reactor is emptied and flushed with a small amount of ethanol in order to remove any residues that have remained. The resulting suspension is filtered. The solid separated off is washed with 400 ml of n-hexane. The solution obtained is freed of volatile constituents at 200-600 mbar and 60-80°C using a rotary evaporator. The suspension obtained is mixed thoroughly with! 200 ml of hexane and stored for 10 hours at 4-8°C. The precipitated solid is separated off by filtration and washed with 150 ml of hexane. The hexane is removed from the resulting clear solution using a rotary evaporator at 200-600 mbar and 60-90°C. 116.3 g of a colourless liquid are obtained. Combined analysis by GC, 1H-NMR and 29Si-NMR shows the following composition of the resulting product, in percent by weight: Based on the above-mentioned values, the conversion is >99 % and the selectivity of the reaction is 89 %. Example 10: 50 g of dried Na2S and 550 ml of dry ethanol are introduced at room temperature into an autoclave having a double-wall glass jacket and a Hastelloy C22 lid + fittings (Buechi AG). The suspension is heated and stirred at 50°C for 20 minutes. A mixture of 80 g of 3- chloropropyl(triethoxysilane) and 48.2 g of 3-chloro- propyl(trichlorosilane) is added to the suspension by means of a compressed-air-operated burette. A further 150 ml of ethanol are added to the suspension by means of the burette. The mixture is heated to 112-117°C, with stirring, and the temperature is maintained for 180 minutes. The mixture is then cooled to room temperature. 1.8 g of formic acid in 50 ml of ethanol are added at 50°C to the reaction solution by means of the pressure burette. The suspension is stirred for 15 minutes at 50°C. A sample is removed and analysed by gas chromatography. Analysis of the reaction mixture by GC shows the following composition in percent by surface area: Based on the above-mentioned values, the conversion is 98 % and the selectivity of the reaction is 88 %. The reactor is emptied and flushed with a small amount of ethanol in order to remove any residues that have remained. The resulting suspension is filtered. The solid separated off is washed with 400 ml of n-pentane. The solution obtained is freed of volatile constituents at 200-600 mbar and 60-80°C using a rotary evaporator. The suspension obtained is mixed thoroughly with 2 00 ml of pentane and stored for 10 hours at 4-8°C. The precipitated solid is separated off by filtration and washed with 150 ml of pentane. The pentane is removed from the resulting clear solution using a rotary evaporator at 200-600 mbar and 60-90°C. 124.5 g of a colourless liquid are obtained. Combined analysis by GC, 1H-NMR and 29Si-NMR shows the following composition of the resulting product, in percent by weight: Based on the above-mentioned values, the conversion is 98 % and the selectivity of the reaction is 85 %. WE CLAIM: 1. Process for the preparation of (mercaptoorganyl) - alkoxysilanes, characterized in that alkali metal sulfide is reacted with a mixture of (haloorganyL) alkoxysilane and (haloorganyl) halo-silane in an alcohol with the exclusion of air, at temperatures of from 0 bo 180°C and under elevated pressure of 0.1 to 10 bar above normal pressure. 2. Process for the preparation of (mercaptoorganyl) - alkoxysilanes as claimed in claim 1, wherein there are obtained as the (mercaptoorganyl), alkoxy-silane compounds of the general formula 1 wherein the substituents R are identical or different and are a C1-C8 alkyl, alkenyl aryl or aralkyl group or a group OR', the substituents R' are identical or different and are a C1-C24, branched or unbranched monovalent alkyl or alkenyl group, aryl group or aralkyl group, R" is a branched or unbranched, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic/aromatic divalent C1-C30 hydrocarbon group which is optionally substituted by F, CI, Br, I, NH2 or NHR', x is 1-3. 3. Process for the preparation of (mercaptoorganyl)-alkoxysilanes as claimed in claim 1, wherein there are used as the (haloorganyl) alkoxysilane compounds of the general formula II wherein the substituents R are identical or different and are a C1-C8 alkyl, alkenyl, aryi or aralkyl group or a group OR', the substituents R' are identical or different and are a C1-C24 branched or unbranched monovalent alkyl or alkenyl group, aryl group or arakyl group, R' is a branched or unbranched, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic/aromatic divalent C1-C30 hydrocarbon group which is optionally substituted by F, CI, Br, I, NH2 or NHR', x is 1-3, Hal is chlorine, bromine, fluorine or iodine. 4. Process for the preparation of (mercaptoorganyl)-alkoxysilanes as claimed in claim 1, wherein there are used as the (haioorganyl) halosilane compounds of the general formula III wherein x, Hal, R and R' are as defined for formula II and the substituents R'' are identical or different and are R or Hal. 5. Process for the preparation of (mercaptoorganyl) - alkoxysilanes as claimed in claim 1, wherein the molar ratio of (haloorganyl) alkoxysilane to (haloorganyl) halosilane is from 0.001 : 1 to 2:1. 6. Process for the preparation of (mercaptoorganyl)-alkoxysilanes as claimed in claim 1 wherein the molar ratio of hydrolysable Si-halogen functions in the mixtures of (haloorganyl) alkoxysilane and (haloorganyl) halosilane to alkali metal sulfide is from 1:0.51 to 1:1.2. 7. Process for the preparation of (mercaptoorganyl)-alkoxysilane as claimed in claim 1 wherein dilithium sulfide (Li2S), disodium sulfide (Na2S) or dipotassium sulfide (K2S) is used as the alkali metal sulfide. 8. Process for the preparation of (mercaptoorganyl)-alkoxysilanes as claimed in claim 1 wherein primary, secondary, tertiary alcohols having from 1 to 24 carbon atoms are used as the alcohol, 9. Process for the preparation of (mercaptoorganyl)-alkoxysilanes as claimed in claim 1 wherein polar, protic, aprotic, basic or acidic additives are added to the reaction mixture at the beginning of the reaction and/or during the reaction and/or at the end of the reaction. Process for the preparation of (mercaptoorganyl)- alkoxysilanes wherein alkali metal sulfide is reacted with a mixture of (haloorganyl) alkoxysilane and (haloorganyl) halosilane in an alcohol with the exclusion of air, at temperatures of from 0 to 180°C and under elevated pressure of 0.1 to 10 bar above normal pressure.

Documents:

680-KOL-2004-(28-10-2011)-CORRESPONDENCE.pdf

680-KOL-2004-(28-10-2011)-OTHER PATENT DOCUMENTS.pdf

680-KOL-2004-(28-10-2011)-PA.pdf

680-kol-2004-abstract.pdf

680-KOL-2004-ASSIGNMENT.pdf

680-kol-2004-claims.pdf

680-KOL-2004-CORRESPONDENCE 1.1.pdf

680-kol-2004-correspondence.pdf

680-kol-2004-description (complete).pdf

680-kol-2004-examination report.pdf

680-kol-2004-form 1.pdf

680-KOL-2004-FORM 13.1.1.pdf

680-KOL-2004-FORM 13.1.2.pdf

680-KOL-2004-FORM 13.pdf

680-kol-2004-form 18.pdf

680-kol-2004-form 2.pdf

680-kol-2004-form 3.pdf

680-kol-2004-form 5.pdf

680-KOL-2004-FORM-27.pdf

680-kol-2004-gpa.pdf

680-KOL-2004-PA.pdf

680-kol-2004-priority document.pdf

680-kol-2004-reply to examination report.pdf

680-kol-2004-specification.pdf

680-kol-2004-translated copy of priority document.pdf