USOO65451.71B2 (12) United States Patent (10) Patent No.: US 6,545,171 B2 Krafczyk et al. (45) Date of Patent: Apr. 8, 2003 (54) PROCESS FOR THE PRODUCTION OF (52) U.S. Cl. ....................................................... 556/427 YELLOW BIS(3-TRIALKOXYSILYALKYL) (58) Field of Search .......................................... 556/427 POLYSULEANES (56) References Cited (75) Inventors: Roland Krafczyk, Rheinfelden (DE); Ulrich Deschler, Sailauf (DE); Björn U.S. PATENT DOCUMENTS Treffeisen, Gundelfingen (DE) 6,140,524 A * 10/2000 Ichinohe et al. ............ 556/427 (73) Assignee: Degussa AG, Düsseldorf (DE) 6,384.256 B1 * 5/2002 Backer et al. .............. 556/427 * cited by examiner (*) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 Primary Examiner Paul F. Shaver U.S.C. 154(b) by 0 days. (74) Attorney, Agent, or Firm-Smith, Gambrell & Russell, LLP (21) Appl. No.: 10/188,033 (57) ABSTRACT (22) Filed: Jul. 3, 2002 Process for the production of yellow bis(3-trialkoxy-silyl (65) Prior Publication Data alkyl)polysulfanes with an iodine color index of s 10 mg iodine/100 ml, in which an organic acid is added to neutral US 2003/00231.06 A1 Jan. 30, 2003 chloroalkyltrialkoxysilane and then reacted with Sodium (30) Foreign Application Priority Data polysulfide (NPS) or sodium sulfide (NaS) and Sulfur or sodium polysulfide (NPS) and NaS in alcohol. Jul. 6, 2001 (DE) ... - - - - - - - - - - - - - - - - - - - - - - - - 101 32939 (51) Int. Cl." ............................... C07F 7/08; CO7F 7/18 9 Claims, No Drawings US 6,545,171 B2 1 2 PROCESS FOR THE PRODUCTION OF An object of the present invention therefore is to provide YELLOW BIS(3-TRIALKOXYSILYALKYL) an alternative process by means of which a yellow bis(3- POLYSULEANES trialkoxysilylalkyl)polysulfane can be obtained and in which the additional use of aggressive chlorosilanes can be dispensed with. INTRODUCTION AND BACKGROUND The present invention relates to a process for the produc SUMMARY OF THE INVENTION tion of yellow bis(3-trialdoxysilyl-alkyl)polysulfanes. The above and other objects of the invention can be The production of bis(3-triethoxysilyl)propyl)- achieved by a process for the production of yellow bis(3- tetrasulfanes by reacting chloropropyltriethoxysilane with trialkoxysilylalkyl)polysulfanes with an iodine color index sodium polysulfide (NPS) is known from DE 2141 159. of s 10 mg iodine/100 ml, preferably 5-7 mg iodine/100 ml, The production of bis(3-triethoxysilylpropyl)disulfane which is characterised in that an organic acid, for example by reacting chloropropyltriethoxysilane with Sodium formic acid, formyl chloride, acetyl chloride, acetic acid or polysulfide (NPS) and sodium sulfide (NaS) is known from mixtures of these acids are added to neutral chloroalkyltri DE 10034493.3. Alternatively, bis(3-triethoxysilyl-propyl) 15 alkoxysilane and then reacted with Sodium polysulfide polysulfanes can be produced by reacting chloropropyltri (NPS) or sodium sulfide (NaS) and sulfur or sodium ethoxysilane with sodium sulfide (NaS) and Sulfur. The polysulfide (NPS) and NaS in alcohol. chloropropyltriethoxysilane used in the known processes The sodium polysulfide (NPS) may be Na-S, where x=2 can be produced by ethanolysis of chloropropyl to 5 or mixtures thereof. trichlorosilane. In this connection a fully reacted product DETAILED DESCRIPTION OF INVENTION with only a very Small proportion of chloropropyl monochlorodiethoxysilane is obtained according to known In accordance with the present invention, preferably the processes such as described in DE 20 61 189 and DE 32 36 bis(3-trialkoxysilylalkyl)polysulfanes may be bis(3- 628. This completely reacted chloropropyltriethoxysilane is triethoxysilylpropyl)polysulfane, bis(3-triethoxysilyl hereinafter termed “neutral'. 25 ethyl)polysulfane, bis(3-trie thoxysilyl)-methyl) If the neutral chloropropyltriethoxysilane is reacted with polysulfane, bis(3-trimethoxysilylpropyl-polysulfane, bis sodium polysulfide (NPS, Na-S, where X=2 to 5 and mix (3-trimethoxysilyl)ethyl)polysulfane or bis(3- tures thereof) or sodium sulfide (Na2S) and sulfur or sodium trimethoxysilyl)methyl)polysulfane. polysulfide (NPS, Na-S, where X=2 to 5 and mixtures AS chloroalkyltrialkoxysilane there can be used thereof) and NaS for the production of bis(3-triethoxysilyl chloropropyltriethoxysilane, chloroethyltriethoxysilane, propyl)polysulfanes according to the processes specified chloromethyltriethoxysilane, chloropropyltrimethoxysilane, above, then a dark yellow to red product (iodine color index chloroethyltrimethoxysilane or chloromethyltrimethoxy 220 mg iodine/100 ml) is obtained. However, a pale yellow silane. Chloropropyltriethoxysilane may particularly prefer product has been introduced on the market that cannot be ably be used. obtained from neutral chloropropyltriethoxysilane. 35 The yellow bis(3-trialkoxysilylalkyl)polysulfanes that The disadvantage of these known processes is that a may be produced according to the invention may be a product having a dark yellow to red color is obtained. polysulfane mixture. The polysulfane chain can on average In order to obtain pale yellow bis(3-triethoxysilyl contain 1.5-10.0 sulfur, preferably 2.0-4.0 sulfur. propyl)polysulfanes (iodine color index s 10 mg iodine/100 40 The organic acid can be added in amounts of 0.1-10 ml) a so-called residual acid content in the form of chloro wt.%, preferably 0.5-5.0 wt.%, particularly preferably propylimonochlorodiethoxysilane must be present in the 10-5.0 wt.%. chloropropyltriethoxysilane. This can be achieved if the Propanol, ethanol or methanol can be used as alcohol. ethanolysis reaction is not carried out to completion. This Preferably the alcohol derived from the alkoxy group may procedure introduces a not inconsiderable additional com be used as alcohol, for example ethanol in the case of ethoxy plication in operational practice however, especially since 45 groups. Lower alkanols, i.e. containing 1 to 5 carbon atoms the residual acid content has to be kept within a very narrow are Suitable. range, and the reaction therefore has to be discontinued in a The reaction mixture can be heated before addition of very targeted manner at a specific point Shortly before sodium polysulfide (NPS) or sodium sulfide (NaS) and complete conversion. 50 sulfur or sodium polysulfide (NPS) and NaS, preferably at Also, an acidification of the neutral chloropropyltri temperatures of 20–90° C. ethoxysilane with alcoholic hydrochloric acid before the The organic acid, for example formic acid or acetic acid, reaction with the aforementioned Sulfurisation agents does can no longer be detected by means of NMR spectroscopy not lead to pale yellow bis(3-triethoxysilylpropyl)- in the product, namely bis(3-trialkoxysilylalkyl) polysulfanes, but instead to dark yellow to red bis(3- 55 polysulfane, after the working up, from which it may be triethoxysilylpropyl)polysulfanes. assumed that no organic acid remains in the product. The production of pale yellow bis(3-triethoxysilyl Bis(3-trialkoxysilylalkyl)polysulfanes produced by the propyl)polysulfanes by adding a small amount of chloro process according to the invention have an iodine color propyltrichlorosilane or chloropropylimonochloro index of s 10 mg iodine/100 ml. diethoxysilane or chloropropyldichloromonoethoxysilane to 60 The process according to the invention has the advantage chloropropyltriethoxysilane before addition of the sulfuriza that the use of aggressive chlorosilanes can be avoided. The tion agents is known from DE 100 24 037.2 and DE 100 45 Small amount of organic acid required for the production of 269.8. yellow bis(3-trialkoxysilylalkyl)-polysulfanes may be pro The disadvantage of this proceSS is that chlorosilanes have Vided simply by adding for example formic acid or acetic to be handled, which on account of their properties are 65 acid to neutral chloropropyl-triethoxysilane. The use of aggressive and highly corrosive compounds that release organic acids has the advantage that no hydrogen chloride hydrogen chloride vapors in the presence of moisture. Vapors are released in the presence of moisture. US 6,545,171 B2 3 4 EXAMPLES boiled for 2 hours under reflux at 82 C. while stirring. After cooling the reaction mixture to room temperature the pre Example 1 cipitated sodium chloride is filtered off and the ethanol is 2.5 g of formic acid are added dropwise at room tem removed on a rotary evaporator. A Subsequent filtration perature to a Solution of 240.8 g of chloropropyltriethoX yields 225.0 g of pale yellow bis(3-triethoxysilylpropyl) ysilane (neutral) in 120 ml of ethanol. 87.1 g of sodium polysulfane with an iodine color index of 5-7 mg iodine/100 polysulfide (NPS, NaS) are then added and the reaction ml, whose identity is confirmed by H-NMR spectroscopy. mixture is boiled for 2 hours under reflux at 82 C. while Example 6 Stirring. After cooling the reaction mixture to room tempera ture the precipitated sodium chloride is filtered off and the Comparison Example 1 ethanol is removed on a rotary evaporator. A Subsequent filtration yields 225.2 g of pale yellow bis(3-triethoxysilyl 87.1 g of Sodium polysulfide are added at room tempera propyl)polysulfane with an iodine color index of 5-7 mg ture to a solution of 240.8 g of chloropropyltriethoxysilane iodine/100 ml, whose identity is confirmed by H-NMR (neutral) in 120 ml of ethanol and the reaction mixture is SpectroScopy. 15 boiled for 2 hours at 82 C. under reflux while stirring. After cooling the reaction mixture to room