US007576231B2

(12) United States Patent (10) Patent No.: US 7,576,231 B2 Tsudera et al. (45) Date of Patent: Aug. 18, 2009

(54) METHOD FOR PRODUCING ISOCYANATE (57) ABSTRACT GROUP-CONTAINING SLOXANE A method for producing an isocyanate group-containing COMPOUND siloxane compound is provided. In this method, a haloge (75) Inventors: Takanobu Tsudera, Joetsu (JP); Tohru nated siloxane compound represented by the following gen Kubota, Joetsu (JP); Ayumu Kiyomori, eral formula (1): Joetsu (JP) (1) R2 R (73) Assignee: Shin-Etsu Chemical Co., Ltd., Tokyo (JP) (*) Notice: Subject to any disclaimer, the term of this R3 3-a patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days. or the following general formula (2) (21) Appl. No.: 11/882,335 (2) RI R4 (22) Filed: Aug. 1, 2007

Si-O--Si-(CH)-X (65) Prior Publication Data

US 2008/O183OO1 A1 Jul. 31, 2008 (30) Foreign Application Priority Data wherein R. R. R. and Rare independently hydrogenatom, Aug. 1, 2006 (JP) ...... 2006-209549 a monovalent hydrocarbon group containing 1 to 8 carbon atoms, or a siloxy group represented by OSiRRR7 wherein (51) Int. Cl. R. R. and Rare a monovalent hydrocarbon group contain C07F 7/10 (2006.01) ing 1 to 8 carbon atoms, X is a halogenatom, n is an integer (52) U.S. Cl...... 556/462:556/414: 556/406; of 1 to 10, a is 0, 1, or 2, and b is an integer of 2 to 9; is reacted 556/460 with a cyanate salt represented by the following general for (58) Field of Classification Search ...... 556/462, mula (3): 556/414, 406, 460 See application file for complete search history. M*(OCN). (3) wherein M represents an alkali metal or an alkaline earth (56) References Cited metal, and m is 1 or 2. The isocyanate group-containing U.S. PATENT DOCUMENTS siloxane compound produced is represented by the following general formula (4): 4,749,806 A 6, 1988 Tkatchenko et al. 5,886,205 A 3, 1999 Uchida et al. (4) R2 R, FOREIGN PATENT DOCUMENTS DE 10240 388 A1 3, 2001 R-i-o Si-(CH2)-NCO 3 JP O8104.755 A * 4f1996 R 3-a JP 10-1486 A 1, 1998 JP 2001-26593. A 1, 2001 JP 2001-026593. A 1, 2001 or the following general formula (5): (5) OTHER PUBLICATIONS RI R European Search Report dated Nov. 14, 2007, issued in correspond ing European Patent application No. 07253013. Si-(CH2)-NCO

Database WPI Week 200136, Derwent Publications Ltd., London, GB, AN 2001-337802, XPO02457180 & JP 2001 026593A. * cited by examiner Primary Examiner Elvis O Price wherein R', R. R. R. n. q, and a are as defined above. (74) Attorney, Agent, or Firm Westerman, Hattori, Daniels & Adrian, LLP. 7 Claims, No Drawings US 7,576,231 B2 1. METHOD FOR PRODUCING ISOCYANATE GROUP-CONTAINING SLOXANE COMPOUND (1) i. CROSS-REFERENCE TO RELATED R-j-o Si-(CH2)-X APPLICATION R3 3-a This non-provisional application claims priority under 35 U.S.C. S 119(a) on Patent Application No. 2006-209549 filed 10 in Japan on Aug. 1, 2006, the entire contents of which are or the following general formula (2) hereby incorporated by reference. 1. Technical Field (2) RI R4 This invention relates to a method for producing an isocy 15 anate group-containing siloxane compound. Si-O Si-(CH2)-X 2. Background Art The isocyanate group-containing siloxane compound con tains both isocyanate group and silicone group in the mol ecule. Since the isocyanate group readily reacts with a func tional group having active hydrogen to form urethane bond and urea bond, the isocyanate group-containing siloxane wherein R. R. R. and Rare independently hydrogenatom, compound is useful as a silicone modifying agent for an a monovalent hydrocarbon group containing 1 to 8 carbon atoms, or a siloxy group represented by OSiRR'R' wherein organic compound having active hydrogen. 25 The isocyanate group-containing siloxane compound has R. R. and R7 are a monovalent hydrocarbon group contain been produced, for example, by reacting an amino group ing 1 to 8 carbon atoms, X is a halogenatom, n is an integer containing siloxane compound with a dialkyl carbonate to of 1 to 10, a is 0, 1, or 2, and b is an integer of 2 to 9; with a produce an alkyl carbamate, and thermally decomposing the cyanate salt represented by the following general formula (3): alkyl carbamate (see, for example, Patent Document 1: JP-A 30 M"(OCN). (3) 10-1486 and Patent Document 2: JP-A 2001-26593), or by reacting an amino group-containing siloxane compound with wherein M represents an alkali metal or an alkaline earth phosgene (see, for example, Patent Document 3: U.S. Pat. No. metal, and m is 1 or 2. The product is the isocyanate group 3,584,024). containing siloxane compound represented by the following However, the method using the thermal decomposition of 35 general formula (4): an alkyl carbamate is associated with the problems such as high price of the amino group-containing siloxane used for the starting material, incapability of producing the isocyanate (4) group-containing siloxane compound at a low cost, and con 40 i || ". tamination of the product with the alkyl carbamate which R-j-o Si-(CH)-NCO failed to undergo thermal decomposition. The method using the phosgene also suffers from various problems such as the R3 high price of the amino group-containing siloxane used for the starting material, incapability of producing the isocyanate 45 group-containing siloxane compound at a low cost, and inad equateness of using the toxic and corrosive phosgene in com mercial production.

(5) 50 R DISCLOSURE OF THE INVENTION Si-(CH2)-NCO

In view of the situation as described above, an object of the present invention is to provide a high purity isocyanate group 55 containing siloxane compound at a low cost. In order to obviate the situation as described above, the wherein R', R. R. R. n. q, and a are as defined above. inventors of the present invention made an intensive study and found a method of reacting a halogenated siloxane compound EFFECTS OF THE INVENTION with a cyanate salt. The present invention has been completed 60 on the basis of Such finding. The production method of the present invention is capable Accordingly, the present invention provides a method for of producing an isocyanate group-containing siloxane com producing an isocyanate group-containing siloxane com poundata low cost by using an inexpensive starting materials, pound. The method comprises reacting a halogenated silox 65 namely, a halogenated siloxane compound and a cyanate salt, ane compound represented by the following general formula and therefore, the method of the present invention has great (1): industrial benefits. US 7,576,231 B2 3 4 DESCRIPTION OF THE PREFERRED cium cyanate, strontium cyanate, and barium cyanate which EMBODIMENTS may be used alone or in combination of two or more. More particularly, the cyanate salt is preferably sodium cyanate or The halogenated siloxane compound used for the starting potassium cyanate. material in the present invention is represented by the follow 5 The cyanate salt is preferably used at 1 to 10 molar amount, ing general formula (1): and more preferably at 1 to 2 molar amount in relation to the halogenated siloxane compound. When used at an amount less than 1 molar amount, a certain proportion of the haloge (1) nated siloxane compound will remain unreacted, and use of 10 the cyanate salt in excess of 10 molar amount may be uneco i || ". nomical. R--0 Si-(CH)-X As described above, the halogenated siloxane compound R3 and the cyanate salt are reacted in the method for producing 3-a the isocyanate group-containing siloxane compound of the 15 present invention, and in Such reaction, an aprotic polar sol vent is preferably used for improving compatibility of the or the general formula (2): halogenated siloxane compound and the cyanate salt. Exem plary aprotic polar solvents include acetonitrile, dimethylfor (2) mamide, N-methyl-2-pyrrolidinone, dimethyl sulfoxide, R4 hexamethylphosphoramide, and diethylene glycol dimethyl ether, which may be used alone or in combination of two or more. More specifically, the preferred is use of dimethylfor mamide. The aprotic polar solventis preferably used at an amount of 25 10 to 200% by weight in relation to the halogenated siloxane compound. When used at an amount in excess of 200% by weight, complicated processing may be required in the post wherein R. R. R. and Rare independently hydrogenatom, treatment resulting in a reduced volumetric yield. When used a monovalent hydrocarbon group containing 1 to 8 carbon at less than 10% by weight, reaction speed may become atoms, or a siloxy group represented by OSiRR'R' wherein 30 reduced to an industrially disadvantageous level. R. R. and R7 are a monovalent hydrocarbon group contain In the present invention, the reaction is preferably carried ing 1 to 8 carbon atoms, X is a halogen atom, n is an integer out in the presence of at least one catalyst selected from phase of 1 to 10, a is 0, 1, or 2, and b is an integer of 2 to 9. transfer catalysts and metal iodide salts. Exemplary phase Exemplary monovalent hydrocarbon groups containing 1 transfer catalysts include a quaternary onium salt, a crown to 8 carbon atoms represented by the R', R. R. R. R. R. 35 ether, a cryptate, and the preferred are quaternary onium salts. and R' include alkyl groups such as methyl group, ethyl The quaternary onium salt is represented by the following group, propyl group, and butyl group, cycloalkyl groups such general formula (7): as cyclopentyl group and cyclohexyl group, aryl groups such as phenyl group, alkenyl groups such as benzyl group, and (RZ)"X (7) alkenyl groups such as vinyl group and allyl group. The R', 40 R,R,R,R,R, and R7 may be either the same or different, wherein R is a monovalent hydrocarbon group containing at and preferably, these groups are methyl group. Exemplary least 1 to 40 carbon atoms, Z is phosphorus atom or nitrogen halogen atoms represented by X include chlorine, bromine, atom, and X is a halogen atom. and iodine, and the preferred is chlorine. n is an integer of 1 to Exemplary quaternary onium salts include cetyltrimethy 10, and in particular, 1 to 6; a is 0, 1, or 2; and b is an integer 45 lammonium chloride, tetrabutylammonium chloride, tetra of 2 to 9, and in particular, 2 to 4. propylammonium chloride, tetrahexylammonium chloride, Among these, the preferred are the halogenated siloxane tetraheptylammonium chloride, tetrapentylammonium chlo compounds represented by the general formula (6): ride, tetramethylammonium chloride, trioctylpropylammo nium chloride, dodecyltrimethylammonium chloride, phe 50 nyltrimethylammonium chloride, (6) hexadecyltrimethylammonium chloride, benzyltriethylam Me monium chloride, benzyltributylammonium chloride, ben Zyltrimethylammonium chloride, didodecyl dimethylammo Me-Si-O nium bromide, dimethyldioctadecylammonium bromide, Me 55 cetyldimethylethylammonium bromide, tetraethylammo nium bromide, tetraoctylammonium bromide, tetrabutylam monium bromide, tetrapropylammonium bromide, phenylt wherein X is as defined above, and Me represents methyl rimethylammonium bromide, benzyltrimethylammonium group. bromide, tetraethylammonium iodide, tetrabutylammonium 60 iodide, ethyltriphenylammonium iodide, methyltripheny The cyanate salt is represented by the general formula (3): lammonium iodide, tetrabutylphosphonium chloride, triph M*(OCN). (3) enylbenzylphosphonium chloride, tetraphenylphosphonium chloride, hexadecyltributylphosphonium bromide, tetrabu wherein M represents an alkali metal or an alkaline earth tylphosphonium bromide, trioctylethylphosphonium bro metal, and m is 1 or 2, and exemplary cyanate salts include 65 mide, tetrabutylphosphonium iodide, and tetraphenylphos lithium cyanate, Sodium cyanate, potassium cyanate, phonium iodide. These quaternary onium salts may be used rubidium cyanate, cesium cyanate, magnesium cyanate, cal either alone or in combination of two or more. US 7,576,231 B2 5 6 Examples of the metal iodide salt include lithium iodide, silane was added dropwise at room temperature. After com Sodium iodide, potassium iodide, rubidium iodide, and pleting the addition, the reaction mixture was heated to 130° cesium iodide, which may be used alone or in combination of C. by heating the flask in an oil bath, and the reaction was two or more as a mixture. More specifically, the preferred is allowed to proceed for 4 hours. After the completion of the use of Sodium iodide or potassium iodide. reaction, the reaction mixture was cooled to room tempera Such catalyst is preferably used at an amount of 0.1 to 20% ture, and 30 g of toluene and 150 g of water was added to by mole, and more preferably at 1 to 10% by mole in relation dissolve the generated salt. The reaction mixture was then to the halogenated siloxane compound. When used at an allowed to stand for 50 minutes, and the organic phase was amount less than 0.1% by mole, reaction speed will be collected. reduced to an industrially disadvantageous level, whereas the 10 A 300 ml distillation still equipped with a capillary, a use in excess of 20% by mole may be uneconomical. thermometer, a vigrew column, and a condenser was purged The reaction is preferably conducted by Suspending the with nitrogen, and the organic phase obtained as described cyanate salt and the catalyst in a solvent, and adding the above was placed in the flask. After reducing the pressure of halogenated siloxane compound dropwise to the Suspension. the flask to 20 kPa and recovering the toluene, the pressure The reaction is preferably conducted in a non-oxidating 15 was reduced to 0.4 kPa, and the resulting product was col atmosphere Such as an inert gas atmosphere of nitrogen. lected by distillation. When the product was measured by gas The reaction temperature of this reaction differs by the chromatography, the resulting propyltris(trimethylsiloxy)si solvent selected. The reaction, however, may be carried out at lane 3-isocianate had a purity of 96.9% and the yield was a temperature in the range of from 0°C. to the boiling point of 63.4% the reaction mixture generated by the reaction. More specifi cally, the reaction is preferably conducted at a temperature in Example 3 the range of 30 to 150° C. Although the reaction time is not particularly limited, the reaction time is typically in the range A 500 ml flask equipped with a reflux condenser, a ther of 1 to 30 hours. mometer, and a dropping funnel was purged with nitrogen, If necessary, the production method of the present inven 25 and 42.7 g of potassium cyanate, 10.2 g of tetrabutylphos tion may further comprise other known steps such as pre phonium iodide, and 200 g of dimethylformamide were treatment steps such as dehydration step, intermediate steps, placed in the flask. While stirring, 98.0 g of 3-chloropropyltris and post-treatment steps such as purification step and recov (trimethylsiloxy)Silane was added dropwise at room tempera ery step. ture. After completing the addition, the reaction mixture was 30 heated to 130° C. by heating the flask in an oil bath, and the EXAMPLES reaction was allowed to proceed for 1 hour. After the comple tion of the reaction, the reaction mixture was cooled to room Next, the present invention is described in further detail by temperature, and the salt generated was separated by filtra referring to the Examples which by no means limit the scope tion. of the present invention. 35 A 300 ml distillation still equipped with a capillary, a thermometer, a vigrew column, and a condenser was purged Example 1 with nitrogen, and the filtrate obtained as described above was placed in the flask. After reducing the pressure of the flask to A 500 ml flask equipped with a reflux condenser, a ther 1.3 kPa and recovering the dimethylformamide, the pressure mometer, and a dropping funnel was purged with nitrogen, 40 was reduced to 0.4 kPa, and the resulting product was col and 26.0 g of potassium cyanate, 2.40 g of potassium iodide, lected by distillation. When the product was measured by gas and 100 g of dimethylformamide were placed in the flask. chromatography, the resulting propyltris(trimethylsiloxy)si While stirring, 98.0 g of 3-chloropropyltris(trimethylsiloxy) lane 3-isocianate had a purity of 98.1% and the yield was silane was added dropwise at room temperature. After com 53.7%. pleting the addition, the reaction mixture was heated to 130° 45 C. by heating the flask in an oil bath, and the reaction was Example 4 allowed to proceed for 4 hours. After the completion of the reaction, the reaction mixture was cooled to room tempera A 100 ml flask equipped with a reflux condenser, a ther ture, and the salt generated was separated by filtration. mometer, and a dropping funnel was purged with nitrogen, A 300 ml distillation still equipped with a capillary, a 50 and 2.6 g of potassium cyanate, 0.22 g of potassium iodide, thermometer, a vigrew column, and a condenser was purged and 10 g of dimethylformamide were placed in the flask. with nitrogen, and the filtrate obtained as described above was While stirring, 9.8 g of 3-chloropropyltris(trimethylsiloxy) placed in the flask. After reducing the pressure of the flask to silane was added dropwise at room temperature. After com 1.3 kPa and recovering the dimethylformamide, the pressure pleting the addition, the reaction mixture was heated to 130° was reduced to 0.4 kPa, and the resulting product was col 55 C. by heating the flask in an oil bath, and the reaction was lected by distillation. When the product was measured by gas allowed to proceed for 7 hours. When the reaction mixture chromatography, the resulting propyltris(trimethylsiloxy)si was measured by gas chromatography, reaction rate of the lane 3-isocianate had a purity of 98.0% and the yield was propyltris(trimethylsiloxy)silane 3-isocianate was 99%. 64.3%. 60 Example 5 Example 2 A 100 ml flask equipped with a reflux condenser, a ther A 500 ml flask equipped with a reflux condenser, a ther mometer, and a dropping funnel was purged with nitrogen, mometer, and a dropping funnel was purged with nitrogen, and 2.1 g of potassium cyanate, 0.45 g of tetrabutylphospho and 26.0 g of potassium cyanate, 2.40 g of potassium iodide, 65 nium bromide, and 10 g of dimethylformamide were placed and 100 g of dimethylformamide were placed in the flask. in the flask. While stirring, 4.9 g of 3-chloropropyltris(trim While stirring, 98.0 g of 3-chloropropyltris(trimethylsiloxy) ethylsiloxy)silane was added dropwise at room temperature. US 7,576,231 B2 7 After completing the addition, the reaction mixture was heated to 130° C. by heating the flask in an oil bath, and the reaction was allowed to proceed for 1.5 hours. When the (1) reaction mixture was measured by gas chromatography, reac tion rate of the propyltris(trimethylsiloxy)silane 3-isocianate was 94%. Example 6 3-a A 100 ml flask equipped with a reflux condenser, a ther 10 mometer, and a dropping funnel was purged with nitrogen, and 2.4 g of potassium cyanate, 0.24 g of potassium iodide, or the following general formula (2) and 16.2 g of dimethylformamide were placed in the flask. While stirring, 9.8g of chloromethyltris(trimethylsiloxy)si 15 (2) lane was added dropwise at room temperature. After complet R4 ing the addition, the reaction mixture was heated to 130°C by heating the flaskin an oil bath, and the reaction was allowed to proceed for 6 hours. When the reaction mixture was mea Sured by gas chromatography, reaction rate of the chlorom ethyltris(trimethylsiloxy)silane was 99%. Example 7 wherein R', R. R. and R are independently hydrogen atom, a monovalent hydrocarbon group containing 1 to A 100 ml flask equipped with a reflux condenser, a ther 25 mometer, and a dropping funnel was purged with nitrogen, 8 carbon atoms, or a siloxy group represented by and 2.5 g of potassium cyanate, 0.25 g of potassium iodide, OSiRRR wherein R. R. and R7 are a monovalent and 16.9 g of dimethylformamide were placed in the flask. hydrocarbon group containing 1 to 8 carbon atoms, X is While stirring, 9.8 g of chloromethylheptamethylcy a halogen atom, n is an integer of 1 to 10, a is 0, 1, or 2, clotetrasiloxane was added dropwise at room temperature. 30 and b is an integer of 2 to 9; with a cyanate salt repre After completing the addition, the reaction mixture was sented by the following general formula (3): heated to 130° C. by heating the flaskin an oil bath, and the reaction was allowed to proceed for 3 hours. When the reac M*(OCN). (3) tion mixture was measured by gas chromatography, reaction wherein M represents an alkali metal or an alkaline earth rate of the chloromethylheptamethylcyclotetrasiloxane was 35 99%. metal, and m is 1 or 2; in the presence of a metal iodide salt to produce the isocyanate group-containing siloxane Example 8 compound represented by the following general formula (4): A 100 ml flask equipped with a reflux condenser, a ther 40 mometer, and a dropping funnel was purged with nitrogen, and 2.3 g of potassium cyanate, 0.23g of potassium iodide, (4) and 15.6 g of dimethylformamide were placed in the flask. i || ". While stirring, 9.8 g of 3-chloropropylheptamethylcy R-i-o Si-(CH)-NCO clotetrasiloxane was added dropwise at room temperature. 45 R3 After completing the addition, the reaction mixture was 3-a heated to 130° C. by heating the flask in an oil bath, and the reaction was allowed to proceed for 2.5 hours. When the reaction mixture was measured by gas chromatography, reac tion rate of the 3-chloropropylheptamethylcyclotetrasiloxane 50 or the following general formula (5): was 100%. Japanese Patent Application No. 2006-209549 is incorpo rated herein by reference. (5) Although some preferred embodiments have been R 55 described, many modifications and variations may be made Si-(CH)-NCO thereto in light of the above teachings. It is therefore to be understood that the invention may be practiced otherwise than as specifically described without departing from the Scope of the appended claims. 60 wherein R', R. R. R. n, b, and a are as defined above. The invention claimed is: 1. A method for producing an isocyanate group-containing 2. The method for producing an isocyanate group-contain siloxane compound comprising the step of reacting a haloge 65 ing siloxane compound according to claim 1 wherein the nated siloxane compound represented by the following gen halogenated siloxane compound is the one represented by the eral formula (1): general formula (6): US 7,576,231 B2 9 10 5. The method for producing an isocyanate group-contain ing siloxane compound according to claim 1 wherein the (6) metal iodide Salt is sodium iodide or potassium iodide. 6. The method for producing an isocyanate group-contain y ing siloxane compound according to claim 1 wherein the se--o Si-(CH2)3-X halogentated siloxane compound starting material is repre Me sented by the general formula (2) and the isocyanate group containing compound is represented by the general formula (5). wherein X is as defined in formula (1), and Me represents 10 7. The method for producing an isocyanate group-contain methyl group. ing siloxane compound according to claim 1 wherein the 3. The method for producing an isocyanate group-contain halogentated siloxane compound starting material is repre ing siloxane compound according to claim 1 wherein the sented by the general formula (1) and the isocyantate group cyanate salt is sodium cyanate or potassium cyanate. containing compound is represented by the general formula 4. The method for producing an isocyanate group-contain 15 (4). ing siloxane compound according to claim 1 wherein the reaction is conducted in an aprotic polar solvent.