Process for producing sulfur-containing silanes by utilizing phase transfer catalysis - Patent Application 20070123333

Abstract

The present invention relates to a process for preparing an aqueous phase preparation by the following steps: (a) preparing an aqueous phase preparation by mixing sodium hydrogen sulfide or sodium sulfide, sulfur, Na2CO3, and / or NaOH with the brine of step (f) and optionally the aqueous suspension of step (h); (b) adding 20 to 100 wt. % of the total amount of phase transfer catalyst; (c) adding a halogen alkyl silane continuously or batchwise while simultaneously adding the remainder of the total amount of phase transfer catalyst batchwise or continuously; (d) optionally adding the brine from (f), optionally adding the aqueous suspension from (h), optionally adding the solid residue from step (k), separating the phases into a lower aqueous suspension and an upper organic phase, and withdrawing the organic phase; (e) feeding the aqueous suspension from (d) and optionally the aqueous suspension from (h) to the aqueous phase preparation; (f) recycling all or a portion of the brine of step (e) to step (a) and optionally to step (d); (g) optionally distilling the remainder of the brine from step (e) to produce an aqueous distillate and an aqueous suspension; (h) optionally recycling the aqueous suspension of step (g) to steps (a) and / or (d) and / or (e); (i) sending the organic phase of step (d) to an evaporation step to produce an organic residue and a low-boiling distillate; (j) separating the organic residue from the evaporation step (i) into sulfur-containing silanes and a solid residue; and (k) optionally recycling the solid residue of step (j) to step (d).

Description

[Technical Field]

[0001] The present invention describes a method for producing sulfur-containing silanes through the use of phase transfer catalysis.

[0002] One area of ​​variation in the process for producing sulfur silanes utilizes a phase transfer catalyst to exchange anions between an aqueous and organic phases. The presence of a salt in the reaction is described in U.S. Patent No. 5,468,893, while U.S. Patent No. 5,663,396 mentions the use of a saturated NaCl solution in the reaction.

[0003] In CN103772427, CN103788121, and CN1038704410, NaCl is used during the formation of the aqueous phase, and a significant amount of water is also used, resulting in a non-saturated solution before the addition of chloropropyltriethoxysilane, and presumably a saturated or nearly saturated solution with little or no suspended solids content after the reaction. After the reaction, the reaction mixture undergoes phase separation between the aqueous and organic phases.

[0004] CN Patent No. 103787373 describes the treatment of the aqueous phase by oxidation, heat treatment, filtration, and multiple-effect evaporation.

[0005] In known processes for producing sulfur silanes using phase transfer catalysts, the by-product NaCl exists as a saturated or nearly saturated aqueous solution. In many parts of the world, environmental regulations prohibit the discharge of significant amounts of NaCl into public wastewater treatment plants or bodies of water. This necessitates the separation of the entire aqueous phase into its components by distillation, which requires significant investment and energy consumption.

[0006] The phase transfer catalyst is stated to be added in one step before adding chloropropyltriethoxysilane, which, due to the long holding time, leads to partial decomposition of the catalyst during the reaction and therefore to higher subsequent catalyst consumption.

[0007] To drive the reaction to completion in a reasonable time, some raw materials must be added in molar excess over others, which results in the use of equal or greater amounts of raw materials, since a certain amount of one or more unreacted raw materials will be present in the aqueous phase and destroyed after the reaction.

[0008] Known methods use pure water in their reactions, which must be supplied, evaporated, condensed, and treated, adding cost to the process. Furthermore, adding water to the reactor results in a larger reaction volume per unit of product than necessary.

[0009] Because the aqueous phase of the reaction is not recycled to subsequent batches, the sulfides remaining from the reaction must be detoxified, thereby consuming significant amounts of processing chemicals and significant amounts of sulfate in the spent salt.

[0010] The object of the present invention is to provide a method that does not use pure water during the preparation of the aqueous phase, which significantly reduces water consumption and negates the equipment and energy costs for desalination of the water by distillation and for processing the distillate in a biological treatment plant. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram of an exemplary method of the present invention.

[0012] The subject of the present invention is a method for producing a method comprising the following steps: (a) preparing an aqueous phase preparation by mixing sodium hydrogen sulfide or sodium sulfide, sulfur, Na2CO3, and / or NaOH with the brine of step (f) and optionally the aqueous suspension of step (h); (b) adding 20 to 100 wt % of the total amount of phase transfer catalyst; (c) adding the halogenalkylsilane continuously or batchwise and simultaneously adding the remainder of the total amount of phase transfer catalyst batchwise or continuously, preferably continuously; (d) optionally adding the brine from step (f); Optionally, adding the aqueous suspension from step (h); optionally adding the solid residue from step (k); separating the phases into a lower aqueous suspension and an upper organic phase and withdrawing the organic phase; (e) providing the aqueous suspension from step (d); Optionally, adding the aqueous suspension from step (h); separating into a salt cake and brine; (f) recycling all or a portion of the brine of step (e) to step (a) and optionally to step (d); (g) optionally distilling the remainder of the brine from step (e) to produce an aqueous distillate and an aqueous suspension; (h) optionally recycling the aqueous suspension of step (g) to steps (a) and / or (d) and / or (e); (i) passing the organic phase of step (d) to an evaporation step to produce an organic residue and a low boiling distillate; (j) separating the organic residue from the evaporation step (i) into sulfur-containing silanes and a solid residue; (k) optionally recycling the solid residue of step (j) to step (d). The present invention relates to a method for producing sulfur-containing silanes.

[0013] The distillate of steps (g) and / or (i) can be detoxified. Any sulfides present in the distillate from process steps (g) and (i) can be detoxified by adding appropriate amounts of hydrogen peroxide and sodium hydroxide.

[0014] The sulfur-containing silanes are represented by Formula I: (R 1 ) 3-m R 2 m Si-R 3 -S x -R 3 -SiR 2 m (R 1 ) 3-m I [In the formula, R 1 are the same or different and are C1 to C10 alkoxy groups, preferably ethoxy, phenoxy groups, or alkyl polyether groups -O-(R'-O) r R″, where R′ are the same or different and are branched or unbranched, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic / aromatic divalent C1 to C30 hydrocarbon groups, preferably CH2CH2, r is an integer from 1 to 30, and R″ is an unsubstituted or substituted, branched or unbranched monovalent alkyl group, preferably an unsubstituted C8 to C15 alkyl group, alkenyl group, aryl group, or aralkyl group; R 2 are the same or different and are a C6 to C20 aryl group, a C1 to C10 alkyl group, a C2 to C20 alkenyl group, a C7 to C20 aralkyl group, or a halogen; R 3 are the same or different, branched or unbranched, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic / aromatic divalent C1 to C30 hydrocarbon radicals, m is the same or different and is 0, 1, 2 or 3, preferably 0; and x is 2 to 10, preferably 2 to 4. The polysulfane silane may be

[0015] Step (a) The purpose of this process step is to prepare the necessary aqueous reagents.

[0016] The sodium hydrogen sulfide in step (a) may be in aqueous solution or hydrate form.

[0017] The sodium sulfide in step (a) may be in aqueous solution or in hydrate form.

[0018] Sodium hydrogen sulfide, sulfur, and the bases Na2CO3 and / or NaOH are represented by the following formula: [ka] to form sodium polysulfide.

[0019] The aqueous sodium hydrogen sulfide solution may be a solution of 30 to 50% by weight, preferably 39 to 43% by weight, of sodium hydrogen sulfide in water.

[0020] The brine from step (f) to be added to step (a) may contain a saturated aqueous solution of process salts and a phase transfer catalyst.

[0021] The aqueous suspension of step (h) to be optionally added to step (a) may contain a saturated aqueous solution of a process salt, a phase transfer catalyst, a solid process salt, and a solid phase transfer catalyst.

[0022] The mixing step (a) could be carried out at a temperature of 23 to 90°C, preferably 70 to 85°C.

[0023] Step (b) The phase transfer catalyst may be a solid or may be a 20 to 80 wt %, preferably 40 to 60 wt %, more preferably 50 wt % aqueous solution.

[0024] The phase transfer catalyst has the general formula: [(Alk)N] + Hal- wherein Alk is a similar or different C2-C 10 It may be a hydrocarbon, preferably a C3 to C5 hydrocarbon, and may be Hal - may be chloride, iodide, or bromide, preferably bromide] The compound may be a tetraalkylammonium halide.

[0025] The phase transfer catalyst may preferably be tetrabutylammonium bromide.

[0026] In step (b), 20-100 wt % of the total amount of phase transfer catalyst could be added, preferably 30-80 wt %, most preferably 40-60 wt %.

[0027] Step (c) Step (c) could be carried out at a temperature of 40 to 100°C, preferably 70 to 85°C.

[0028] In step (c), the halogen alkyl silane is reacted with NaS n+1 would be able to react with

[0029] Halogen alkyl silanes are (R 1 ) 3-m R 2 m Si-R 3 -Hal, where R 1 , R 2 , R 3 and m are as previously described, and Hal is a halogen, preferably chlorine.

[0030] Halogen alkyl silanes are 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 propyl(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), 1-chloromethyl(methoxydimethylsilane), [ka]

[0031] [ka]

[0032] [ka]

[0033] [ka] It could be.

[0034] In step (c), 0-80% by weight, preferably 40-60% of the total amount of phase transfer catalyst could be added.

[0035] Step (d) The phase separation time can be from 60 seconds to 24 hours, preferably from 20 minutes to 120 minutes.

[0036] An additional amount of the brine of step (f) can be added to the phase separator before or during phase separation. Optionally, the brine from step (f) added to step (d) can contain a saturated aqueous solution of a process salt and a phase transfer catalyst.

[0037] The aqueous suspension from step (h) can be added before or during phase separation. Optionally, the aqueous suspension of step (h) added to step (d) can contain a saturated aqueous solution of process salts, phase transfer catalyst, solid process salts, and solid phase transfer catalyst.

[0038] The solid residue of step (k) can be added before, during, or after phase separation. Optionally, the solid residue of step (k) added to step (d) can contain solid process salts and solid phase transfer catalysts.

[0039] Phase separation can be achieved using centrifugal force or gravity. Phase separation can be achieved in a vessel. Phase separation can be achieved in a centrifuge.

[0040] If gravity is used for phase separation, the organic phase could be withdrawn through a side outlet and / or the lower aqueous suspension phase could be withdrawn from the bottom. Phase separation can be carried out in a Nutsche filter.

[0041] Step (e) Separation of the aqueous suspension from step (d) into salt cake and brine could be done by settling or filtration. A decanter centrifuge can be used for settling. Filtration can be done in a vacuum filter. Filtration can be done in a pressure filter. Filtration can be done in a Nutsche filter. The Nutsche filter used in step (d) may be the same as the Nutsche filter used in step (e).

[0042] The aqueous suspension of step (h) that is optionally added to step (e) may contain a saturated aqueous solution of a process salt, a phase transfer catalyst, a solid process salt, and a solid phase transfer catalyst.

[0043] Step (f) Between 5 and 100% by weight of the brine could be recycled to step (a), preferably between 10 and 50% by weight.

[0044] Between 0 and 95% by weight of the brine could be recycled to step (d), preferably between 10 and 50% by weight.

[0045] Step (g) The brine of step (e) may be concentrated in a brine distillation to obtain an aqueous distillate and an aqueous suspension containing the process salt. The brine distillation may be carried out in an overhead stirred vessel. The brine distillation may be carried out in a multiple-effect evaporator. Heating for the distillation may be carried out using indirect combustion, steam, or inorganic or organic heat transfer fluids. Condensation may be carried out directly or indirectly, preferably indirectly using cooling water. System heating and condensation may be achieved using vapor compression. The pressure during the distillation may be from 8 mbar absolute to 3000 mbar absolute, preferably from 30 to 1050 mbar absolute, and most preferably from 200 to 500 mbar absolute. The aqueous suspension containing the process salt and brine may have a water content of 40 to 73% by weight, preferably from 50 to 68% by weight.

[0046] Step (h) Between 0 and 100% by weight of the aqueous suspension, preferably 0% by weight, could be recycled to step (a).

[0047] Between 0 and 100% by weight of the aqueous suspension could be recycled to step (d).

[0048] Between 0 and 100% by weight of the aqueous suspension could be recycled to step (e).

[0049] Step (i) The evaporation step can be carried out in a vessel. The evaporation step can be carried out in a thin film evaporator. The evaporation step can be carried out in a short path evaporator. The pressure during evaporation can be between 5 and 500 mbar absolute, preferably between 10 and 50 mbar absolute.

[0050] Step (j) Salts precipitated in the organic phase during distillation step (i) can be removed in a product polishing step. The solid precipitate can be removed as a solid or suspended in a slurry. The clarified liquid (product) can be passed through an optional activated carbon bed and polishing filter for final clarification. The device for product polishing can be one or a combination of a filter or a centrifuge.

[0051] Step (k) The solid content of the solid residue separated in step (j) and returned to step (d) may be 0-99% by weight, preferably 10-90% by weight.

[0052] The method can be performed continuously or batchwise. Where different process steps are performed in different pieces of equipment, these can be performed simultaneously on successive batches.

[0053] The brine of step (f) added in step (a) and / or step (d) can be from any previous batch.

[0054] The aqueous suspension of step (h) added in step (a) and / or step (d) and / or step (e) may be that of any previous batch.

[0055] The solid residue of step (k) added in step (d) can be from any previous batch.

[0056] The brine of step (f) added in step (a) and / or step (d), and / or the aqueous suspension of step (h) added in step (a) and / or step (d) and / or step (e), and / or the solid residue of step (k) added in step (d) may be from any previous batch.

[0057] In the recycle step, the brine of step (f) can be fed in any successive batches.

[0058] In the recycle step, the aqueous suspension of step (h) can be fed in any successive batches.

[0059] In the recycling step, the solid residue of step (k) can be fed to any successive batches.

[0060] In the recycling step, the brine of step (f), and / or the aqueous suspension of step (h), and / or the solid residue of step (k) can be fed in any successive batches.

[0061] An exemplary method is shown in FIG.

[0062] Adding the phase transfer catalyst stepwise or continuously during the reaction results in a shorter overall catalyst retention time, and therefore less catalyst is lost to decomposition, allowing for a reduction in the total amount of catalyst.

[0063] The reaction recipe is set up so that most of the by-products produced precipitate, so little / no water is needed during the reaction to keep them in solution. Therefore, the reactor and downstream equipment can be much smaller than expected for known technologies, thus reducing investment costs.

[0064] As mentioned previously, unreacted starting materials in the aqueous phase tend to remain in solution. This results in a sulfide-free salt cake. Therefore, the salt produced as a by-product does not need to be treated to oxidize sulfides, thereby minimizing the cost of detoxification equipment and chemicals.

[0065] In the process of the present invention, no or less pure water is used during the preparation of the aqueous phase. Instead, part of the brine from the previous batch is used, which also serves as a fluid to keep the solid components of the reaction mixture in suspension. Only the water introduced into the process by the raw materials and the water produced in the reaction need be removed. This significantly reduces water consumption and negates the equipment and energy costs for desalination of the water by distillation and for processing the distillate in a biological treatment facility.

[0066] The solubility of the starting materials and phase transfer catalyst in aqueous solution is generally greater than that of the by-products. Therefore, the remaining starting materials and phase transfer catalyst added in excess tend to remain in solution, while the by-products tend to form the filter cake. This brine containing these valuable raw materials is recycled to successive batches. Thus, the addition of raw materials and phase transfer catalyst per batch can be reduced while maintaining the desired excess of these raw materials.

[0067] Example The average sulfur chain length and S2-S10 content of the final product were determined according to ASTM D6844-02 using an Aglient Technologies Series 1260 Infinity II HPLC instrument with the following parameters: Column: Bakerbond C18 (RP), 5 μm, 4.6 × 250 mm, flow rate 1.50 ml / min, λ = 254 nm, column temperature 30 °C, mobile phase: a mixture of 200 ml of tetrabutylammonium bromide solution (made from 400 mg of tetrabutylammonium bromide in 1 L of deionized water), 450 ml of ethanol, and 1350 ml of methanol.

[0068] Example 1 (4,4,13,13-tetraethoxy-3,14-dioxa-8,9-dithia-4,13-disilahexadecane) without recycle step (comparative example) Sodium carbonate (94.5 g, 0.89 mol, 1.153 equiv.), sodium hydrogen sulfide hydrate (112.9 g, 0.81 mol, 1.044 equiv., 43%), and water (286.0 g, 15.9 mol, 20.6 equiv.) were heated to 72 °C. The reaction mixture was stirred at 72 °C for 5-10 min. Subsequently, sulfur (27.5 g, 0.86 mol, 1.112 equiv.) was added while maintaining the temperature at 70-75 °C. After stirring the reaction mixture at 72 °C for 45 min, tetra-n-butylammonium bromide (TBAB, 9.4 g, 15.5 mmol, 0.020 equiv., 50% in deionized water) and (3-chloropropyl)triethoxysilane (CPTEO, 372 g, 1.54 mol, 2.00 equiv.) were added to the reaction mixture while maintaining the temperature at 72-78 °C. The suspension was stirred at 75°C for 3 hours. The conversion of (3-chloropropyl)triethoxysilane in the organic phase was determined by GC and found to be 98.6%. Water (412.5 g) was then added to dissolve all salts, and the phases were separated at 75°C. The aqueous phase (0.94 kg) was discarded. After the organic phase was cooled to room temperature, it was subjected to removal of light boilers by thin-film evaporation. After filtration, the product was obtained as a clear yellowish liquid with an average sulfur chain length of 2.17 and an S2-S10 concentration of 93.32%.

[0069] Example 2 (4,4,13,13-tetraethoxy-3,14-dioxa-8,9-dithia-4,13-disilahexadecane) with recycle step (example of the invention) (a) Sodium hydrogen sulfide solution (102 g, 0.785 mol, 1.00 equiv, 43%), Na2CO3 (83.2 g, 0.785 mol, 1.00 equiv), and brine (f) (291 g containing the remaining reagents, phase transfer catalyst, and / or saturated aqueous solution of product from one or more previous reaction batches using the same recipe) were combined and stirred at 72 °C for 10 minutes. Sulfur (28.0 g, 0.873 mol, 1.112 equiv) was then added while maintaining the temperature at 70 °C to 75 °C. After stirring the reaction mixture at 72 °C for 45 minutes, (b) Tetra-n-butylammonium bromide (TBAB, 5.06 g, 7.9 mmol, 0.010 equiv., 50% in deionized water) was added.

[0070] (c) (3-chloropropyl)triethoxysilane (CPTEO, 378 g, 1.57 mol, 2.00 equivalents) was then added to the reaction mixture at a rate of 6.3 g / min while maintaining a temperature of 72-78 °C. The suspension was stirred at 75 °C for 3 hours. The conversion of (3-chloropropyl)triethoxysilane in the organic phase was determined by GC and found to be 98.2%.

[0071] (d) After this step, 424 g of brine (containing an aqueous solution of the remaining reagents, phase transfer catalyst, and / or products from one or more previous reaction batches using the same recipe) was added and the phases were separated at 75°C.

[0072] (e) The aqueous suspension (h) from the brine distillation of the previous batch was then added to the aqueous phase of the phase separation step and the mixture was filtered to yield a salt cake (176 g) and brine (aqueous solution for the next brine recycling reaction).

[0073] (f) The remaining brine (839 g) was used in the next batch.

[0074] (g) 130 g of this brine were introduced into a rotary evaporator for distillation. The water was partially extracted at 300 mbar absolute, leaving an aqueous suspension (85 g).

[0075] (h) Should be used in the next batch.

[0076] (i) After the organic phase was cooled to room temperature, it was purified by thin film evaporation.

[0077] (j) After filtration, 350 g of product, 93% yield, was obtained as a clear yellowish liquid with an average sulfur chain length of 2.15 and an S2-S10 concentration of 95.16%.

[0078] Example 3 (4,4,15,15-tetraethoxy-3,16-dioxa-8,9,10,11-tetrathia-4,15-disilaoctadecane) without recycle step (comparative example) Sodium hydroxide (40.3 g, 1.01 mol, 0.97 equiv.), sodium hydrogen sulfide hydrate (142.1 g, 1.017 mol, 0.98 equiv., 43%), and water (79.2 g, 4.40 mol, 4.24 equiv.) were heated to 72 °C. The reaction mixture was stirred at 72 °C for 10 min. Subsequently, sulfur (91.8 g, 2.87 mol, 2.76 equiv.) was added in two portions while maintaining the temperature at 70-75 °C. After stirring the reaction mixture at 72 °C for 15 min, tetra-n-butylammonium bromide (TBAB, 8.7 g, 13.5 mmol, 0.013 equiv., 50% in deionized water) and (3-chloropropyl)triethoxysilane (CPTEO, 499.7 g, 2.07 mol, 2.00 equiv.) are added to the reaction mixture while maintaining the temperature between 72 and 78 °C.

[0079] The suspension was stirred at 75°C for 2 hours. Water (321 g) was then added to dissolve all salts, and the phases were separated at 75°C. The aqueous phase (464 g) was discarded. After the organic phase was cooled to room temperature, it was subjected to removal of low boiling materials by thin film evaporation. After filtration, the product was obtained as a clear yellowish liquid with an average sulfur chain length of 3.72 and an S2-S10 concentration of 93.33%.

[0080] Example 4 (4,4,15,15-tetraethoxy-3,16-dioxa-8,9,10,11-tetrathia-4,15-disilaoctadecane) with recycle step (example of the invention) (a) Sodium hydroxide (40.2 g, 1.01 mol, 0.97 equiv.), sodium hydrogen sulfide hydrate (133 g, 1,017 mol, 0.98 equiv., 43%), and brine (79.3 g containing an aqueous solution of the remaining reagents, phase transfer catalyst, and / or product from one or more previous reaction batches using the same recipe) were heated to 72°C. The reaction mixture was stirred at 72°C for 10 minutes. Subsequently, sulfur (91.8 g, 2.86 mol, 2.76 equiv.) was added in two portions while maintaining the temperature at 70-75°C. After stirring the reaction mixture at 72°C for 15 minutes, (b) tetra-n-butylammonium bromide (TBAB, 6.7 g, 10.4 mmol, 0.010 equiv., 50% in deionized water, added in 4 equal portions); (c) and (3-chloropropyl)triethoxysilane (CPTEO, 500 g, 2.08 mol, 2.00 equivalents, added at a rate of 8.5 g / min) were added to the reaction mixture while maintaining the temperature between 72 and 78 °C. The suspension was stirred at 75 °C for 2 hours.

[0081] (d) Brine (324.6 g, containing an aqueous solution of the remaining reagents, phase transfer catalyst, and / or products from one or more previous reaction batches using the same recipe) was then added, and the mixture was allowed to settle and the phases were separated.

[0082] (e) The aqueous suspension was filtered, resulting in a salt cake and brine (aqueous solution for subsequent brine recycling reactions).

[0083] (f) The brine was used in the next batch.

[0084] (g) - (h) - (i) After the organic phase was cooled to room temperature, it was subjected to removal of low boiling materials by thin film evaporation.

[0085] (j) After filtration, the product was obtained as a clear yellowish liquid with an average sulfur chain length of 3.71 and an S2-S10 concentration of 94.11%.

Claims

1. Steps below: (a) Sodium hydrogen sulfide or sodium sulfide, sulfur, Na ２ CO ３ and / or NaOH with the brine of step (f) and optionally the aqueous suspension of step (h), (b) adding 20-100 wt. % of the total amount of phase transfer catalyst; (c) adding a halogenalkylsilane continuously or batchwise; Simultaneously adding the remainder of the total amount of phase transfer catalyst batchwise or continuously; (d) optionally adding the brine from step (f); Optionally adding the aqueous suspension from step (h); Optionally adding the solid residue from step (k); separating the phases into a lower aqueous suspension and an upper organic phase and withdrawing the organic phase; (e) providing the aqueous suspension from step (d); Optionally adding the aqueous suspension from step (h); separating into a salt cake and a brine; (f) recycling all or a portion of the brine of step (e) to step (a) and, optionally, to step (d); (g) optionally distilling the remainder of the brine from step (e) to produce an aqueous distillate and an aqueous suspension; (h) optionally recycling said aqueous suspension of step (g) to steps (a) and / or (d) and / or (e); (i) passing the organic phase of step (d) to an evaporation step to produce an organic residue and a low boiling distillate; (j) separating the organic residue from the evaporation step (i) into sulfur-containing silanes and a solid residue; (k) optionally recycling said solid residue of step (j) to step (d).

1. A method for producing a sulfur-containing silane, comprising the steps of: The sulfur-containing silane has the formula I': (R 1 ) 3 Si-R 3 -S x -R 3 -Si(R 1 ) 3 I' [In the formula, R 1 is the same or different and is a C1 to C10 alkoxy group; R 3 is the same or different and is a branched or unbranched, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic / aromatic divalent C1 to C30 hydrocarbon group; x is 2 to 10. The polysulfane silane of the above formula.

2. The phase transfer catalyst has the general formula: <h2 style=";text-align:left;direction:ltr">([(Alk)<h2 style=";text-align:left;direction:ltr"> ４ <h2 style=";text-align:left;direction:ltr"> N]<h2 style=";text-align:left;direction:ltr"> ＋ <h2 style=";text-align:left;direction:ltr"> Hal<h2 style=";text-align:left;direction:ltr"> － wherein Alk is a similar or different C ２ ~C １０ It may be a hydrocarbon, such as Hal － may be chloride, iodide, or bromide.

2. A method for producing a sulfur-containing silane according to claim 1, characterized in that the tetraalkylammonium halide is

3. 2. The method for producing sulfur-containing silanes according to claim 1, wherein the phase transfer catalyst is tetrabutylammonium bromide.

4. 2. The method for producing sulfur-containing silanes according to claim 1, characterized in that in step (d), an additional amount of the brine of step (f) can be added to the phase separator before or during the phase separation.

5. 2. The process for producing sulfur-containing silanes according to claim 1, characterized in that in step (d), the aqueous suspension from step (h) can be added before or during the phase separation.

6. 2. The method for producing sulfur-containing silanes according to claim 1, characterized in that in step (d), the solid residue of step (k) can be added before, during or after the phase separation.

7. 2. The method for producing sulfur-containing silanes according to claim 1, characterized in that in step (f), 5 to 100 wt. % of the brine is recycled to step (a) and 0 to 95 wt. % of the brine is recycled to step (d).

8. 2. The method for producing sulfur-containing silanes according to claim 1, characterized in that in step (h), 0-100% by weight of the aqueous suspension is recycled to step (a), 0-100% by weight of the aqueous suspension is recycled to step (d), and 0-100% by weight of the aqueous suspension is recycled to step (e).

9. 2. The process for producing sulfur-containing silanes according to claim 1, characterized in that the process is batchwise.

10. 2. The method for producing sulfur-containing silanes according to claim 1, characterized in that the brine of step (f) added in step (a) and / or step (d) is from any previous batch.

11. 2. The method for producing sulfur-containing silanes according to claim 1, characterized in that the aqueous suspension of step (h) added in step (a) and / or step (d) and / or step (e) is that of any previous batch.

12. 2. The method for producing sulfur-containing silanes according to claim 1, wherein the solid residue of step (k) added in step (d) is from any previous batch.

13. 2. A method for producing sulfur-containing silanes according to claim 1, characterized in that in a recycling step, the brine of step (f), and / or the aqueous suspension of step (h), and / or the solid residue of step (k) are fed in any successive batches.

14. 2. The method for producing sulfur-containing silanes according to claim 1, characterized in that in step (e), the aqueous suspension from step (h) can be added before or during said separation.

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