PROCESS FOR PRODUCING FLUOROSILICONE DEFOAMER COMPOSITION

Abstract: A process for producing fluorosilicone/dimethylsilicone copolymer composition for use as a defoamer.

Description: PROCESS FOR PRODUCING FLUOROSILICONE DEFOAMER COMPOSITION CROSS-REFERENCE TO RELATED APPLICATIONS This application claims rights of priority from U.S. Provisional Patent Application Serial No. 60/172,497, filed December 17, 1999. FIELD OF THE INVENTION The invention relates to a process for producing a fluorosilicone composition, more specifically to a process for producing a fluorosilicone/ dimethylsilicone copolymer composition for use as a defoamer. BRIEF DESCRIPTION OF THE RELATED ART Silicone polymers are well suited as defoamers in a number of important applications, for example, food processing, pulp and paper processing, detergent products and oil recovery. In the oil recovery application, defoamers are used to increase the rate of oil recovery. Fluorosilicones are often the best performing materials for this application, and their relatively high cost per pound is offset by the high value of the higher oil recovery rates, particularly in offshore oil wells where the cost of operating oils rigs is very high. (See, for example, U.S. Patent Nos. 3,974,120; 3,997,496; 5,350,824; 4,597,894; 5,116,928; and 5,300,609.) The composition of crude oils varies widely, and a defoamer of a specific chemical composition may work well at some oil platforms and poorly at others. What is needed is a single defoamer for offshore oil recovery that is suitable for a variety of crude oil compositions. SUMMARY OF THE INVENTION The present invention is directed to a process for producing a fluorosilicone/ dimethylsilicone copolymer composition comprising: (a) reacting a composition comprising: (i) a silanol-end stopped diorganopolysiloxane of the formula: HO-(RR 1 SiO) x -H wherein R is a (Cι-C6)alkyl or (C 2 -Ce )alkenyl, R 1 is alkylperfluoroalkyl, preferably (CH2)nR 3 wherein R 3 is a perfluoro(C 1 -C6)alkyl group and n is from 2 to 6, and x is from 3 to 20; (ii) a silanol end-stopped polysiloxane of the formula: HO-(R' 2 SiO) y -H wherein each R' is independently a (Cι-Cό)alkyl or (C2-C6 )alkenyl, y is from 3 to 20, (i) and (ii) are each present in an amount of from about 25 to about 75 mole %, in the presence of a catalyst; (b) condensing the mixture for an appropriate time and temperature; and (c) removing the formed water of condensation, wherein a 25 to 75 mole percent fluorsilicone/75 to 25 mole percent dimethylsilicone block copolymer having enhanced crude oil defoaming ability is produced. The present invention is also directed to a process for producing a fluorosilicone/ dimethylsilicone copolymer composition comprising: (a) reacting a composition comprising: (i) a cyclic trimer of the formula: (R 2 SiO) 3 wherein each R 4 is independently (Ci-Cβjalkyl, cycloalkyl, or fluorinated alkyl such that at least one R 4 is an alkylperfluoroalkyl, preferably (CH 2 ) n R 5 wherein R 5 is a perfluoro(Cι-C6)alkyl group, and n is from 2 to 6, (ii) a silanol end-stopped polysiloxane of the formula: HO-(R 6 2 SiO)y-H wherein R 6 is, independently a (Cι-C 6 )alkyl or (C 2 -C 6 )alkenyl, y is from 3 to 20, (i) and (ii) each present in an amount of from 25 to 75 mole %, until it is miscible, and in the presence of a catalyst; (b) condensing the mixture in the presence of the catalyst for an appropriate time and temperature; and (c) removing the formed water of condensation, wherein a 25 to 75 mole percent fluorsilicone/75 to 25 mole percent dimethylsilicone block copolymer having enhanced crude oil defoaming ability is produced. The present invention is also directed to a copolymer having first structural units of the formula -(RR α SiO)-, and second structural units of the formula -(R' 2 SiO)-, wherein R is a (Cι-C 6 )alkyl or (C 2 -C 6 )alkenyl, R 1 is alkylperfluoroalkyl, preferably (CH 2 ) n R 3 wherein R 3 is a perfluoro(Cι-C-6)alkyl group and n is from 2 to 6, and R' is independently a (Cι-C 6 )alkyl or (C2-Gs) alkenyl. The present invention is also directed to a copolymer having first structural units of the formula -(R 4 2 SiO)-, and second structural units of the formula -(R 6 2SiO)-, wherein R 4 is independently (Cι-C 6 )alkyl, cycloalkyl, or fluorinated alkyl such that one R 4 is an alkylperfluoroalkyl, preferably (CH 2 ) n R 5 wherein R 5 is a perfluoro(Cι-C6)alkyl group, and n is from 2 to 6, and R 6 is independently a (Cι-Cό)alkyl or (C2-C6 )alkenyl. The present invention is also directed to defoamers comprising the copolymers of the present invention. The present invention is further directed to methods of using the copolymers of the present invention, and to a methods of defoaming a liquid, preferably a crude oil, using the copolymers of the present invention. DETAILED DESCRIPTION OF THE INVENTION In a preferred embodiment, the process of the present invention comprises adding together a silanol end-stopped diorganopolysiloxane of the formula HO-(RR 1 SiO) x -H, wherein R is a (Cι-C 6 )alkyl or (C2-C6 )alkenyl, more preferably, methyl, ethyl, vinyl or phenyl, and even more preferably methyl or ethyl, and most preferably, methyl; R 1 is a fluorinated alkyl, such as 3,3,3- trifluoropropyl, 4,4,4,3,3-pentafluoro-l -butyl, and the like, preferably of 3 to 8 carbon atoms, most preferably, R 1 is 3,3,3-trifluoropropyl, and x is from 3 to 20; and a silanol end-stopped polysiloxane of the formula HO-(R'2SiO) y -H, wherein each R' is independently a (Cι-C 6 )alkyl or (C2-G-)alkenyl, y is from 3 to 20. Preferably, the condensation temperature is from about 50 to about 125°C, more preferably from about 105 to about 120°C. Preferably, the viscosity of the block copolymer produced is from about 1,000 to about 50,000 centistokes, more preferably from about 2,000 to about 12,000 centistokes. Condensation proceeds until the desired viscosity level is reached. In a second preferred embodiment, the process of the present invention comprises adding together a cyclic trimer of the formula (R 4 2 SiO)3, wherein each R 4 is independently a (Cι-Cό)alkyl, cycloalkyl or fluorinated alkyl such that one R 4 is a fluorinated alkyl, such as 3,3,3-trifluoropropyl, 4,4,4,3,3-pentafluoro-l-butyl, and the like, preferably, of 3 to 8 carbon atoms, more preferably R 4 is methyl or ethyl and one R 4 is preferably 3,3,3- trifluoropropyl, most preferably, R 4 is methyl and one R 4 is most preferably 3,3,3-trifluoropropyl; and a silanol end-stopped polysiloxane of the formula HO-(R 6 2 SiO) r H, wherein each R 6 is independently a (Cι-C 6 )alkyl or (C 2 - C 6 )alkenyl, more preferably, methyl, ethyl, vinyl or phenyl, and even more preferably methyl or ethyl, and most preferably, methyl, and y is from 3 to 20. Preferably the temperature at which the mixture is heated is from about 50 to about 125°C, even more preferably from about 105 to about 120°C. Preferably, the viscosity of the block copolymer produced is from about 1,000 to about 50,000 centistokes, more preferably from about 2,000 to about 12,000 centistokes. Condensation proceeds until the desired viscosity level is reached. In a third preferred embodiment of the present invention, there is a copolymer having first structural units of the formula -(RR 1 SiO)-, and second structural units of the formula -(R'2SiO)-, wherein R is a (Cι-C 6 )alkyl or (C2-C6 )alkenyl, R 1 is alkylperfluoroalkyl, preferably (CH.)nR 3 wherein R 3 is a perfluoro(Cι-C 6 )alkyl group and n is from 2 to 6, and each R' is independently a (Cι-C 6 )alkyl or (C2-C6 )alkenyl. Preferably, R is methyl, ethyl, vinyl or phenyl, more preferably, methyl or ethyl, and most preferably, methyl. R 1 is a fluorinated alkyl, such as 3,3,3-trifluoropropyl, 4,4,4,3,3-pentafluoro-l -butyl, and the like, preferably of 3 to 8 carbon atoms, most preferably, R 1 is 3,3,3- trifluoropropyl. Preferably, the copolymer is a block copolymer having from about 25 to about 75% fluorosilicone and from about 75 to about 25% dimethylsilicone, more preferably from about 45 to about 55% fluorosilicone and from 55 to 45 % dimethylsilicone, and most preferably from about 50% fluorosilicone to about 50% dimethylsilicone. In a fourth preferred embodiment of the present invention, there is a copolymer having first structural units of the formula -(R 4 2SiO)-, and second structural units of the formula -(R 6 2SiO)-, wherein each R 4 is independently (G-C^alkyl, cycloalkyl, or fluorinated alkyl such that at least one R 4 is an alkylperfluoroalkyl, preferably (CH2)nR 5 wherein R 5 is a perfluoro(Cι-C6)alkyl group, and n is from 2 to 6, and each R 6 is independently a (Cι-Cό)alkyl or (C2- C 6 ) alkenyl. At least one R 4 is a fluorinated alkyl, such as 3,3,3- trifluoropropyl, 4,4,4,3,3-pentafluoro-l -butyl, and the like, of preferably 3 to 8 carbon atoms, more preferably, R 4 is methyl or ethyl and one R 4 is preferably 3,3,3-trifluoropropyl, most preferably, R 4 is methyl and one R 4 is most preferably 3,3,3-trifluoropropyl. Preferably, R 6 is methyl, ethyl, vinyl or phenyl, more preferably, methyl or ethyl, and most preferably, methyl. Preferably, the copolymer is a block copolymer having from about 25 to about 75% fluorosilicone and from about 75 to about 25% dimethylsilicone, more preferably from about 45 to about 55% fluorosilicone and from 55 to 45 % dimethylsilicone, and most preferably from about 50% fluorosilicone to about 50% dimethylsilicone. The silanol-stopped polymers can be converted to trimethylsiloxy- stopped polymers by treatment with a silylating agent, such as hexamethyldisilazane ("HMDZ"). Alternatively, trimethylsilanol could be added to the two siloxanes and co-condensed to produce trimethyl- terminated products. As used herein, the term "(Cι-C6)alkyl" means a linear or branched alkyl group containing from 1 to 6 carbons per group, such as, for example, methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, pentyl, hexyl, preferably methyl. As used herein, "(C2-C6) alkenyl" means a straight or branched chain alkenyl group containing from 2 to 6 carbon atoms per group and at least one double bond between two carbon atoms per group, such as, for example, vinyl, propenyl and butenyl. As used herein, "cyclic trimer" refers to cyclic trisiloxanes, such as hexamethylcyclotrisiloxane or (fluoro example). Catalysts suitable for use in the present invention are those that effectively produce a condensation reaction, a ring opening of the cyclic material, or both, depending on the process used. In the first preferred embodiment of the present invention, a catalyst that promotes a condensation reaction is used; in the second preferred embodiment, both a condensation catalyst and a ring opening catalyst are necessary. Examples of suitable catalysts for use in the present invention include, but are not limited to, alkali metal compounds or silanolates, more preferably alkali metal hydroxides, even more preferably sodium hydroxide and potassium hydroxide, and most preferably, sodium hydroxide. The catalyst may be used in conjunction with a promotor such as an organic ether, such as for example, The process of the present invention is advantageous because it produces fluorosilicone/ dimethylsilicone block copolymers. The products made by these processes have several advantages over the processes of the prior art. A single 40 to 60 mole percent fluorosilicone/ 40 to 60 mole percent dimethylsilicone block copolymer composition may be used effectively for crude oil recovery. The present invention is also directed to defoamers comprising the copolymers of the present invention as well as to a method of defoaming a liquid, preferably a crude oil, by adding the copolymers of the present invention to the crude oil. The copolymers of the present invention may also be used as additives to liquids. The copolymers of the present invention are effective as defoamers when used with other types of defoamers, such as for example, polyalkylsiloxanes such as polydimethylsiloxane. When used in conjunction with other liquids, the amount of defoamer necessary is drastically reduced, thereby significantly reducing the cost. The respective disclosures of all United States patents referenced herein are hereby specifically incorporated herein. Example Samples produced by both embodiments of the present invention were evaluated as defoamers for crude oil. Time until foaming began after the initial defoaming by the addition of the defoamer to the crude oil was measured, and results are shown in Table 1. The longer the time until refoaming, the better the performance of the defoamer. Table 1 - Time Until Defoaming polymer. Types 1 A and IB represent samples produced using the first preferred embodiment. Type 1 A samples represent lower viscosity materials taken at 110°C; Type IB samples represent higher viscosity materials taken at 120°C Type 2A represents samples produced using the second preferred embodiment. Samples were taken at different times during condensation to represent different viscosities.

Claims: Claims: 1. A process for producing a fluorosilicone/ dimethylsilicone copolymer composition comprising: (a) reacting a composition comprising: (i) a silanol-end stopped diorganopolysiloxane of the formula: HO-(RR i SiO) x -H wherein R is a (Cι-C 6 )alkyl or (C -C 6 )alkenyl, R 1 is alkylperfluoroalkyl, preferably (CH 2 ) n R 3 wherein R 3 is a perfluoro(Cι-C6)alkyl group and n is from 1 to 6, and x is from 3 to 9; (ii) a silanol end-stopped polysiloxane of the formula: HO-(R' 2 SiO) y -H wherein each R' is independently a (Cι-C 6 )alkyl or (C 2 -C6 )alkenyl, y is from 3 to 9, (i) and (ii) are each present in an amount of from about 40 to about 60 mole %, in the presence of a catalyst; (b) condensing the mixture for an appropriate time and temperature; and (c) removing the formed water of condensation, wherein a 40 to 60 mole percent fluorsilicone/40 to 60 mole percent dimethylsilicone block copolymer having enhanced crude oil defoaming ability is produced. 2. A process for producing a fluorosilicone/ dimethylsilicone copolymer composition comprising: (a) reacting a composition comprising: (i) a cyclic trimer of the formula: (R 4 2 SiO) 3 wherein each R 4 is independently (Cι-C 6 ) alkyl, cycloalkyl, or fluorinated alkyl such that at least one R 4 is an alkylperfluoroalkyl, preferably (CH2)nR 5 wherein R 5 is a perfluoro(Ci-Co)alkyl group, and n is from 1 to 6, (ii) a silanol end-stopped polysiloxane of the formula: HO-(R 6 2 SiO)y-H wherein R 6 is, independently a (Cι-Cό)alkyl or (C2-C6 )alkenyl, y is from 3 to 9, (i) and (ii) each present in an amount of from 40 to 60 mole %, at a temperature above 50°C until it is miscible, and in the presence of a catalyst; (b) condensing the mixture in the presence of the catalyst for an appropriate time and temperature; and (c) removing the formed water of condensation, wherein a 40 to 60 mole percent fluorsilicone/40 to 60 mole percent dimethylsilicone block copolymer having enhanced crude oil defoaming ability is produced.

Inventors: GOSH NANCY E, RAZZANO JOHN S, GOSH, NANCY, E., RAZZANO, JOHN, S.
Applicants: GEN ELECTRIC, GENERAL ELECTRIC COMPANY
Application year: 2001
Main classification: C08G77
IPC codes: B01D19, C08G77