United States Patent (19) 11 Patent Number: 4,820,674 Shiozawa et al. 45) Date of Patent: Apr. 11, 1989 54 PROCESS FOR PREPARING A 58) Field of Search ....................... 502/169, 172, 230; HYDROSLYLATION CATALYST 556/479, 136; 549/206, 211 75 Inventors: Kouji Shiozawa, Saitama; Yoshiharu (56) References Cited Okumura, Tokyo; Chihiro Imai, U.S. PATENT DOCUMENTS Kanagawa; Nobukazu Okamoto, 3,220,972 11/1965 Lamoreaux ......................... 502/169 Saitama, all of Japan 3,624,119 11/1971 Rothe.................................. 502/169 73) Assignee: Toa Nenryo Kogyo Kabushiki Kaisha, 3,814,731 6/1974 Nitzsche .............................. 502/169 Tokyo, Japan Primary Examiner-Patrick P. Garvin Assistant Examiner-Elizabeth Irzinski 21 Appl. No.: 149,092 Attorney, Agent, or Firm-Wenderoth, Lind and Ponack 22 Filed: Jan. 27, 1988 57 ABSTRACT A process for preparing a hydrosilylation catalyst by 30 Foreign Application Priority Data dissolving chloroplatinic acid H2PtCl6 in a cyclic ether or cyclic ester containing at least 3 carbon atoms, and Jan. 29, 1987 JP Japan .................................. 62-18916 maintaining the resulting solution at a temperature of at (51 Int. Cl. .............................................. B01J 31/00 least 3O C. 52 U.S. Cl. .................................... 502/169; 502/172; 502/230 4. Claims, No Drawings 4,820,674 1. 2 the resulting solution at a temperature of at least 30 C., PROCESS FOR PREPARING A preferably from 50° to 120° C. HYDROSILYLATION CATALYST DETAILED DESCRIPTION OF THE BACKGROUND OF THE INVENTION INVENTION This invention relates to a process for preparing a A process for preparing a hydrosilylation catalyst hydrosilylation catalyst which is preferably used in according to the present invention will be fully de synthesizing a silane coupling agent and, more particu scribed hereinafter. larly, to a process for preparing a hydrosilylation cata First, starting materials, reaction conditions and the lyst which is preferably used in synthesizing, by hy like used in preparing a hydrosilylation catalyst accord drosilylation reaction, a silane coupling agent of which ing to the present invention are described in detail. demand is enlarged as an indispensable material in the development of ultrafasionable composite materials. (1) ETHERS Heretofore, the following catalysts or processes (1) to Linear or cyclic ethers containing at least 3 carbon (4) have been known as catalysts or processes which are 15 atoms such as ethyl ether, butyl ether, phenyl ether, used in synthesizing silane coupling agents by a hy anisole, tetrahydrofuran, furan, tetrahydropyran, and drosilylation reaction. However, any of these catalysts dioxane can be used herein. The preferred ethers are or processes present problems as described hereinafter: those containing no aliphatic multiple bonds. (1) as solution of chloroplatinic acid H2PtCl66H2O in Of these, tetrahydrofuran is particularly preferred. isopropanol (see J.Amer. Chem.Soc., VOL.82, 20 The amount of these ethers used is usually at least 1 3602(1960)). mole per 1 mole of chloroplatinic acid, particularly This catalyst requires a considerably long period preferably from 100 to 2,000 moles. There is no upper (generally called induction period) until it exhibits a limit thereof. It is possible to use the ethers as solvents steady catalytic activity. Further, it must be pretreated for the hydrosilylation reaction in producing the silane with a portion of a reaction reagent prior to the reac 25 coupling agent. tion. (2) A platinum-beta-diketone complex (see Japanese (2) ESTERS Patent Publin. No.24947/1975). Linear or cyclic esters containing at least 3 carbon When this catalyst is used, hydrosilylated products atoms such as methyl acetate, amyl acetate, methyl can be obtained in a relatively high yield by a reaction 30 propionate, ethylbenzoate, dimethyl phthalate, gamma of allyl chloride and trichlorosilane as described in the butyrolactone, delta-valerolactone, and epsilon Japanese Patent Publin. However, the reaction tempera caprolactone can be used herein. The preferred esters ture is high, the reaction time is long, and the prepara are those containing no aliphatic multiple bonds. tion of the catalyst takes a long time. Of these, gamma-butyrolactone is particularly pre (3) A process wherein a choloroplatinic acid catalyst 35 ferred. is used in the presence of phenothiazine, diphenylamine The amount of the esters used is the same as that of or the like (Japanese Patent Publin, No.29873/1981) the ethers described above. When this process is utilized, the induction period of (3) PREPARATION OF HYDROSILYLATION the catalyst is reduced and it is possible to lower the CATALYST reaction temperature. However, the yield of hy In order to prepare a hydrosilylation catalyst (the drosilylated objective products is low. reaction product of chloroplatinic acid and ether or (4) A Reaction product of chloroplatinic acid and ester) according to the present invention, chloroplatinic cyclohexanone (Japanese Patent publin. No.41132/1978) acid is dissolved in the ether or ester described above, When this catalyst is used, hydrosilylated products 45 and preferably, the mixture is heated under a nitrogen which are objective products are obtained in a rela atmosphere usually for at least 5 minutes, preferably for tively high yield. However, cyclohexanone reacts with 30 minutes to 2 hours. The heating temperature is at silane compounds such as trichlorosilane. least 30° C., preferably from 50 C. to 120° C. When the It is therefore an object of the present invention to boiling point of the ethers or esters used is lower than provide a process for preparing a hydrosilylation cata 50 this temperature range, the mixture is heated to a tem lyst which meets the following requirements: (1) the perature below the boiling point of the ethers or esters. preparation of the catalyst is simple; (2) the induction While thus obtained reaction product of chloroplatinic period can be shortened; (3) the catalyst or the auxiliary acid and ethers or esters can be used as catalyst as it is, catalyst is not consumed, and (4) the reaction proceeds it is preferred that a desiccating agent such as anhy under mild conditions and the silane coupling agent can 55 drous sodium sulfate, anhydrous sodium carbonate or be obtained in a high yield. sodium carbonate is usually added to the reaction prod SUMMARY OF THE INVENTION uct, and thereafter used as a hydrosilylation catalyst. Among these desiccating agents, sodium carbonate The present invention relates to a process for prepar and anhydrous sodium carbonate are particularly pre ing a hydrosilylation catalyst wherein the long induc 60 ferred because they can remove hydrogen chloride tion period which was the drawback of the prior cata formed in the preparation step of the catalyst. lyst can be eliminated or shortened by subjecting chlo When chloroplatinic acid is dissolved in the ethers or roplatinic acid H2PtCl6heretofore used in this reaction esters and the solution is heated at a temperature at least as the catalyst to predetermined treatment. 30 C, preferably from 50° C. to 120° C., it is believed A process for preparing a hydrosilylation catalyst 65 that platinum is chloroplatinic acid is converted into a according to the present invention comprises the steps divalent state and platinum which is in a divalent state of dissolving chloroplatinic acid H2PtCl6 in an ether or exhibits high catalytic activity towards the hydrosilyla ester containing at least 3 carbon atoms, and retaining tion reaction. That is, according to the process for pre 4,820,674 3 4. paring the hydrosilylation catalyst based on the present gram of chloroplatinic acid (IV) H2PtCl6.6H2O, and invention, divalent platinum having high catalytic ac 200ml of tetrahydrofuran. The mixture was heated for tivity can be efficiently and readily formed. one hour at the reflux temperature of tetrahydrofuran When a small amount of the hydrosilylation catalyst (about 65° C) under a nitrogen atmosphere. The result formed by the present invention is added to, for exam ing solution was dried with anhydrous sodium sulfate to ple, an equimolar mixture of trichlorosilane and allyl prepare a hydrosilylation catalyst. (Catalyst A) chloride, a remarkable exothermic reaction rapidly oc curs. When only chloroplatinic acid is added, such an EXAMPLE 2 exothermic reaction does not occur. Thus, when the Preparation of Catalyst (B) hydrosilylation catalyst prepared by the present inven O tion is used to carry out the hydrosilylation reaction, the A three-neck flask equipped with a reflux condenser, hydrosilylation catalyst according to the present inven stirring rod and thermometer was charged with one tion remarkably shortens the induction period also ac gram of chloroplatinic aid (IV), and 200ml of gramma companying the exothermic reaction. (4) In order to use butyrolactone. The mixture was heated for one hour at the hydrosilylation catalyst according to the present 15. a temperature of 100° C. under a nitrogen atmosphere. invention to synthesize a silane coupling agent by hy The resulting solution was dried with anhydrous so drosilylation reation, the hydrosilylation catalyst may dium sulfate to prepare a hydrosilylation catalyst (Cata be added to unsaturated compounds such as allyl chlo lyst B) ride and allyl methacrylate (olefins) and silane com pounds such as trichlorosilane and trimethoxy silane EXAMPLE 3 may be dropwise added, while maintaining the solution Preparation of Catalyst (C) at a predetermined