Method for promoting hydrosilylation reactions to prepare ester-functional siloxane oligomers - Patents.com

Abstract

The method for preparing ester functional siloxanes involves the hydrosilylation of alkenyl ethers and organohydrogensiloxane oligomers. Platinum hydrosilylation catalysts and accelerators are used in the method.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 63 / 270075, filed October 21, 2021. U.S. Provisional Patent Application No. 63 / 270075 is incorporated herein by reference.

[0002] A method for preparing ester-functional siloxane oligomers is disclosed. More specifically, the method uses a promoter to improve the yield and selectivity of the hydrosilylation of allyl ethers with organohydrogensiloxane oligomers. [Background technology]

[0003] Currently, siloxane-(meth)acrylate compounds can be synthesized via a direct platinum-catalyzed hydrosilylation reaction of (meth)acryloxy-functional alkenyl compounds with organohydrogensiloxane oligomers, as exemplified in Equation 1 below by the reaction of allyl methacrylate 1 with 1,1,1,3,5,5,5-heptamethyltrisiloxane 2. However, this direct reaction has the disadvantage that there are significant amounts of by-products, including oxy-silyl esters and alkylene hydrosilylation products (exemplified in Equation 1 by oxy-silyl esters 4 and propylene hydrosilylation adducts 5, respectively), resulting in low yields of the desired product (exemplified by MD'M-ALMA 3 in Equation 1), on the order of 45%-55%. The oxy-silyl ester by-products have a similar boiling point as MD'M-ALMA, making distillation difficult, time-consuming, and expensive.

[0004] [ka] Summary of the Invention

[0005] A method for preparing an ester-functional siloxane, comprising combining a starting material comprising (A) an alkenyl ether and (B) an organohydrogensiloxane oligomer in the presence of (C) a hydrosilylation reaction catalyst and (D) an accelerator.

DETAILED DESCRIPTION OF THE INVENTION

[0006] More specifically, the method for preparing an ester-functional siloxane is (1) (A) Formula (A1):

[0007]

Chemical formula

[0008] [ka] (In formula, formula

[0009] [ka] each group is independently selected from the group consisting of cyclohexyl and phenyl; 6 is an independently selected alkyl group of 1 to 6 carbon atoms, and each subscript x is 0, 1, or 2; Combining starting materials comprising Each alkyl group R 6 If present, the expression

[0010] [ka] As used herein, "yield ratio" refers to the weight / molecular weight of ester functional siloxane:the weight / molecular weight of oxy-silyl ester by-product.

[0011] Step (1) of the above method may include mixing and heating the starting materials. The starting materials may be combined in any order. Alternatively, (C) the platinum hydrosilylation reaction catalyst and (D) the accelerator may be combined with one of (A) the alkenyl ether and (B) the organohydrogensiloxane oligomer to form a reaction mixture, and then the other of (A) the alkenyl ether and (B) the organohydrogensiloxane oligomer may be metered continuously or intermittently into the reaction mixture. For example, starting materials including (A) the alkenyl ether, (C) the platinum hydrosilylation reaction catalyst, and (D) the accelerator may be combined to form a reaction mixture, and (B) the organohydrogensiloxane oligomer may be metered into the reaction mixture.

[0012] Alternatively, the method may optionally further comprise combining (C) a platinum hydrosilylation reaction catalyst and (D) an accelerator prior to step (1) of combining (A) the alkenyl ether and (B) the organohydrogensiloxane oligomer. Starting material (E) a solvent may be used in or prior to step (1), for example, to facilitate mixing of the starting materials, for example, to facilitate mixing of (C) the platinum hydrosilylation reaction catalyst and (D) the accelerator. Mixing may be performed at ambient or elevated temperatures, for example, from RT to below the boiling point of the selected solvent, for example, from RT to 50°C.

[0013] Without wishing to be bound by theory, it is believed that by combining (C) a platinum hydrosilylation reaction catalyst and (D) a promoter, optionally in the presence of (E) a solvent, prior to combining with other starting materials, a platinum-ligand complex is formed (if the promoter is a ligand), which complex can then act as a catalyst in step (1). The starting materials introduced above are described in detail below.

[0014] (A) Alkenyl ether The starting material (A) has the formula (A1):

[0015] [ka] where R 1 is a monovalent hydrocarbon radical of 1 to 12 carbon atoms, R 2 is selected from the group consisting of hydrogen and alkyl groups of 1 to 12 carbon atoms. 2 can also be H.

[0016] Or, for each R 1 R may be selected from the group consisting of alkyl groups of 1 to 12 carbon atoms and alkenyl groups of 2 to 12 carbon atoms. 1 and / or R 2 The alkyl group of may be methyl, ethyl, propyl (including n-propyl and isopropyl), butyl (including n-butyl, t-butyl, sec-butyl, and isobutyl), pentyl (including n-pentyl, cyclopentyl, and branched isomers having 5 carbon atoms), hexyl (including n-hexyl, cyclohexyl, and branched isomers having 6 carbon atoms). Alternatively, the alkyl group may be methyl or ethyl, or may be methyl. R 1 The alkenyl group of the formula may be a vinyl group, an allyl group, a hexenyl group, or a branched alkenyl group. For example, the alkenyl group may be of the formula

[0017] [ka] and (A) may be allyl methacrylate, which is commercially available from a variety of sources, such as Sigma Aldrich, Inc. (St. Louis, Missouri, USA). 1 The alkenyl group of the formula

[0018] [ka] wherein (A) may be allyl acrylate, which is commercially available from a variety of sources, such as Sigma Aldrich, Inc.

[0019] Or, R 1 When is methyl, (A) may be allyl acetate, which is commercially available from a variety of sources, such as Sigma Aldrich, Inc.

[0020] Alternatively, the starting material (A) has the formula (A2):

[0021] [ka] wherein R 5 is selected from the group consisting of H, alkyl and aryl; R 3 is selected from the group consisting of H, alkyl and aryl; R 4 is selected from the group consisting of H, alkyl, and aryl. 5 , R 3 and R 4Suitable alkyl groups may have 1 to 12 carbon atoms, alternatively 1 to 6 carbon atoms. The alkyl groups are exemplified by methyl, ethyl, propyl (including n-propyl and / or isopropyl), butyl (including n-butyl, tert-butyl, sec-butyl, and / or isobutyl), pentyl, hexyl, heptyl, octyl, decyl, dodecyl (and branched isomers having 5 to 12 carbon atoms), and the alkyl groups are further exemplified by cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl. Alternatively, the alkyl groups may be selected from the group consisting of methyl, ethyl, propyl, and butyl, alternatively from the group consisting of methyl, ethyl, and propyl, alternatively from the group consisting of methyl and ethyl. Alternatively, the alkyl group may be methyl. Suitable aryl groups may be monocyclic or polycyclic and may have pendant hydrocarbyl groups. For example, aryl groups include phenyl, tolyl, xylyl, and naphthyl, as well as aralkyl groups such as benzyl, 1-phenylethyl, and 2-phenylethyl. Alternatively, the aryl group may be monocyclic, such as phenyl, tolyl, or benzyl, or the aryl group may be phenyl. Alternatively, R 5 , R 3 and R 4 may each be selected from the group consisting of H and methyl. Alternatively, R 5 may be H. Alternatively, R 3 may be H. Alternatively, R 4 may be methyl. Examples of suitable commercially available compounds for starting material (A) include allyl (meth)acrylate. Suitable (meth)acrylate-functional alkenyl compounds are commercially available, for example, from Sigma Aldrich, Inc. (St. Louis, Missouri, USA).

[0022] (B) Organohydrogensiloxane oligomer The starting material (B) used in step (1) of the method described in this specification is an organohydrogensiloxane oligomer. The organohydrogensiloxane oligomer has at least one silicon-bonded hydrogen atom per molecule, or exactly one silicon-bonded hydrogen atom per molecule. The organohydrogensiloxane oligomer has the unit formula (B1): (R 1 3 SiO 1 / 2 ) a (R 1 2 HSiO 1 / 2 ) b (HR 1 SiO 2 / 2 ) c (R 1 2 SiO 2 / 2 ) d (wherein each R 1 is as defined above, and the subscripts a, b, c, and d each represent the average number of units in the unit formula, with 0 ≦ a ≦ 2, 0 < b ≦ 2, 0 ≦ c ≦ 3, 0 ≦ d ≦ 3, the amount of (a + b) = 2, the amount of (b + c) ≧ 1, and the amount of (a + b + c + d) having a value such that 2 to 10) It may have. Alternatively, 8 ≧ (a + b + c + d) ≧ 2, or 6 ≧ (a + b + c + d) ≧ 2, or 3 ≧ (a + b + c + d) ≧ 2, or (a + b + c + d) = 3.

[0023] Alternatively, the starting material (B) is of the formula (B2)

[0024]

Chemical formula

[0025]

Chemical formula

[0026] Alternatively, the starting material (B) is a compound of formula (B4)

[0027] [ka] Or formula (B5)

[0028] [ka] (In the formula, R 1 is as defined above).

[0029] The organohydrogensiloxane oligomer suitable for starting material (B) is known in the art and commercially available.For example, the organohydrogensiloxane oligomer suitable for starting material (B) can be 1,1,1,3,5,5,5-heptamethyltrisiloxane or 1,1,3,3-tetramethyldisiloxane, which can be obtained, for example, from Sigma-Aldrich, Inc. (St. Louis, Missouri, USA).Alternatively, starting material (B) can be 1,1,1,3,5,5,5-heptamethyltrisiloxane.

[0030] The starting material (B) is an organohydrogensiloxane oligomer or a siloxane having at least one moiety, e.g., R 1The alkenyl ether (A) and the organohydrogensiloxane oligomer (B) may be a combination of two or more oligomers that differ from each other in the selection of the alkyl group, the position of the silicon-bonded hydrogen, and / or the DP. However, the molar ratio of the amount of the organohydrogensiloxane oligomer (B) to the amount of the alkenyl ether (A), (B):(A), is 1.25:1 to 0.75:1, or 1.0:1 to 1.1:1, used in step (1).

[0031] (C) Platinum hydrosilylation catalyst The starting material (C) is a hydrosilylation catalyst. The hydrosilylation catalyst promotes the reaction between the alkenyl group in the starting material (A) alkenyl ether and the silicon-bonded hydrogen atom in the starting material (B) organohydrogensiloxane. This catalyst contains platinum. The hydrosilylation catalyst may be the above-mentioned (C1) platinum metal, (C2) a compound of platinum metal such as chloroplatinic acid (Speier's catalyst), chloroplatinic acid hexahydrate, platinum dichloride, (C3) a complex of this compound with an alkenyl-functional organopolysiloxane, or (C4) a platinum compound microencapsulated in a matrix or core-shell structure. Complexes of platinum with low molecular weight organopolysiloxanes include platinum complexes with 1,3-diethyl-1,1,3,3-tetramethyldisiloxane (Karstedt's catalyst) and platinum complexes with vinyldimethylsiloxane complexes such as Pt(0) complex in tetramethyltetravinylcyclotetrasiloxane (Ashby's complex). Alternatively, the hydrosilylation reaction catalyst may be a (C5) compound or complex as described above microencapsulated in a resin matrix. Specific examples of platinum-containing catalysts suitable for use herein include chloroplatinic acid in either hexahydrate or anhydrous form, or platinum-containing catalysts obtained by a process comprising reacting chloroplatinic acid with an aliphatically unsaturated organosilicon compound such as divinyltetramethyldisiloxane, or alkene-platinum-silyl complexes as described in U.S. Pat. No. 6,605,734 to Roy. These alkene-platinum-silyl complexes may be prepared, for example, by mixing 0.015 moles of (COD)PtCl 20.045 moles of COD and 0.0612 moles of HMeSiCl 2 and COD represents cyclooctadienyl. Other exemplary hydrosilylation reaction catalysts are described in U.S. Patents 2,823,218 to Speier, 3,159,601 to Ashby, 3,220,972 to Lamoreaux, 3,296,291 to Chalk et al., 3,419,593 to Willing, 3,516,946 to Modic, 3,814,771 to Karstedt, and 3,171,113 to Langmuir et al. 30, Chandra No. 3,928,629, Lee et al. No. 3,989,668, Lee et al. No. 4,766,176, Lee et al. No. 4,784,879, Lee et al. No. 5,017,654, Togashi No. 5,036,117, Chung et al. No. 5,175,325, and Brown No. 0 347 895(A) to Togashi et al. Suitable hydrosilylation catalysts for the starting material (C) are commercially available, for example SYL-OFF™ 4000 catalyst and SYL-OFF™ 2700 are available from DSC.

[0032] The starting material (C) may be a platinum hydrosilylation catalyst or a combination of two or more of the above platinum hydrosilylation catalysts. The amount of (C) platinum hydrosilylation catalyst used in the present process depends on various factors, including the selection of the starting materials (A), (B), and (D), but the amount of catalyst is sufficient to catalyze the hydrosilylation reaction of SiH and alkenyl groups, or the amount of catalyst is sufficient to provide at least 0.01 ppm, alternatively at least 0.05 ppm, alternatively at least 0.1 ppm, alternatively at least 0.5 ppm, alternatively at least 1 ppm, by weight of platinum group metal, based on the total amount of starting materials (A), (B), (C), and (D) used in step (1) of the process described herein. At the same time, the amount of catalyst is sufficient to provide up to 1,000 ppm, alternatively up to 800 ppm, alternatively up to 500 ppm, alternatively up to 100 ppm, by weight of platinum group metal, based on the total amount of starting materials (A), (B), (C), and (D) used in step (1) of the process described herein.

[0033] (D) Accelerator The starting material (D) used in the methods described herein is a (D) promoter, which has the general formula:

[0034] [ka] (In formula, formula

[0035] [ka] is independently selected from the group consisting of cyclohexyl and phenyl; 6 is an independently selected alkyl group of 1 to 6 carbon atoms, and each subscript x is 0, 1, or 2. 6 When present, R is covalently attached to a carbon atom in the cyclohexyl or phenyl ring. 6 Suitable alkyl groups for include methyl, ethyl, propyl, and butyl, alternatively methyl or ethyl, alternatively methyl. Each subscript x may be 0, 1, or 2, alternatively 0 or 1, alternatively x=0. Each instance of the subscript x may be the same or different. Alternatively, the (D) accelerator may be selected from the group consisting of (D1) bis(diphenylphosphino)methane, (D2) bis(dicyclohexylphosphino)methane, and (D3) a combination of both (D1) and (D2). Alternatively, the accelerator may be (D1) bis(diphenylphosphino)methane. Alternatively, the accelerator may be (D2) bis(dicyclohexylphosphino)methane. Each of these compounds is commercially available from a variety of sources, for example, Sigma Aldrich, Inc., TCI America, or Alfa Aesar.

[0036] The amount of accelerator used in the method is sufficient to provide both a yield ratio of ester functional siloxane:oxy-silyl ester by-product of ≧2.5:1 and a conversion of ≧50% of starting materials (A) and (B). Alternatively, the amount of accelerator can be sufficient to provide both a yield ratio of ≧3:1 and a conversion of ≧50% of starting materials (A) and (B). Alternatively, the amount of accelerator can be sufficient to provide both a yield ratio of ≧3.4:1 and a conversion of ≧50% of starting materials (A) and (B). Alternatively, the amount of accelerator can be >0.5 moles to <1.25 moles per mole of platinum from starting material (C). Alternatively, the amount of accelerator can be at least 0.75 moles, alternatively >0.5 moles, per mole of platinum from starting material (C), while at the same time, the amount of accelerator can be up to 1 mole, alternatively <1.25 moles.

[0037] (E) Solvent Starting material (E) is a solvent, which may be used to facilitate mixing of one or more starting materials. For example, prior to step (1), (C) platinum hydrosilylation catalyst may be provided in a solvent, and / or (C) platinum hydrosilylation catalyst and (D) accelerator may be combined in a solvent. Suitable solvents include polydialkylsiloxanes, monohydric alcohols, aromatic hydrocarbons, aliphatic hydrocarbons, and combinations of two or more thereof. Polyalkylsiloxanes having suitable vapor pressures may be used as solvents, including hexamethyldisiloxane, octamethyltrisiloxane, hexamethylcyclotrisiloxane, and other low molecular weight polyalkylsiloxanes such as DOWSIL™ 200 Fluid and DOWSIL™ OS FLUID, available from DSC, from 0.5 cSt to 1.5 cSt. The monohydric alcohol may have 1 to 6 carbon atoms, such as methanol, ethanol, isopropanol, n-propanol, n-butanol, t-butanol, isobutanol, and / or sec-butanol. The aromatic hydrocarbon may have 6 to 20 carbon atoms, such as benzene, toluene, ethylbenzene, or xylene. The aliphatic hydrocarbon may have 1 to 20 carbon atoms, such as heptane, hexane, cyclohexane, or octane. Monohydric alcohols and hydrocarbon solvents are commercially available from a variety of sources, such as Sigma-Aldrich, Inc. (St. Louis, Missouri, USA). The starting material (E) may be one or a combination of two or more of the above solvents.

[0038] The amount of solvent will depend on a variety of factors, including the type of solvent selected, as well as the amounts and types of other starting materials selected for use in the method, however, the amount of solvent may be from 0% to 10% based on the total weight of all starting materials used in step (1).

[0039] The method may optionally further comprise adding (F) a (meth)acrylate polymerization inhibitor (inhibitor) before and / or during step (1).

[0040] (F) (Meth)acrylate Polymerization Inhibitor Starting material (F) is a (meth)acrylate polymerization inhibitor (inhibitor) that may be optionally used in the process. Inhibitors may include, but are not limited to, radical scavengers, antioxidants, light stabilizers, UV absorbers, or combinations thereof, or may be any of these. Such inhibitors are known in the art and include chemical compounds or moieties that can interact with and inactivate free radicals, for example, via scavenging the free radicals through the formation of covalent bonds therewith. The inhibitor may alternatively be a polymerization retarder, i.e., a compound that reduces the initiation and / or propagation rate of radical polymerization. For example, the inhibitor may include or be oxygen gas. In general, inhibitors are utilized to prevent and / or inhibit the formation of by-products that may be formed via radical polymerization of some portion of starting material (A).

[0041] The inhibitor (F) may include a phenolic compound, a quinone or hydroquinone compound, an N-oxyl compound, a phenothiazine compound, a hindered amine compound, or a combination thereof. Examples of phenolic compounds include phenol, alkylphenols, aminophenols (e.g., p-aminophenol), nitrosophenols, and alkoxyphenols. Specific examples of such phenolic compounds include o-, m-, and p-cresol (methylphenol), 2-tert-butyl-4-methylphenol, 6-tert-butyl-2,4-dimethylphenol, 2,6-di-tert-butyl-4-methylphenol, 2-tert-butylphenol, 4-tert-butylphenol, 2,4-di-tert-butylphenol, 2-methyl-4-tert-butylphenol, 4-tert-butyl-2,6-dimethylphenol or 2,2'-methylenebis(6-tert-butyl-4-methylphenol), 4,4'-oxybiphenyl, 3,4-methylenedioxydiphenol (sesamol), 3,4-dimethylphenol, pyrocatechol (1,2-dihydroxybenzene), 2-(1'-methylcyclohex-1'-yl)-4,6-dimethylphenol, 2- or 4-(1'-phenyleth-1'-yl)phenol, 2-tert-butyl- 6-Methylphenol, 2,4,6-tris-tert-butylphenol, 2,6-di-tert-butylphenol, nonylphenol, octylphenol, 2,6-dimethylphenol, bisphenol A, bisphenol B, bisphenol C, bisphenol F, bisphenol S, 3,3',5,5'-tetrabromobisphenol A, 2,6-di-tert-butyl-p-cresol, methyl 3,5-di-tert-butyl-4-hydroxybenzoate, 4-tert-butylpyrocatechol, 2-hydroxybenzyl alcohol, 2-methoxy-4-methylphenol, 2,3,6-trimethylphenol, 2,4,5-trimethylphenol, 2,4,6-trimethylphenol, 2-isopropylphenol, 4-isopropylphenol, 6-isopropyl-m-cresol, n-octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 1,1,3-Tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxyethyl isocyanurate, 1,3,5-tris(2,6-dimethyl-3-hydroxy-4-tert-butylbenzyl)isocyanurate pentaerythrityl tetrakis[p-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,6-di-tert-butyl-4-dimethylaminomethylphenol, 6-sec-butyl-2,4-dinitrophenol, octadecyl 3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate, hexadecyl 3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate, octyl 3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate 3-Thia-1,5-pentanediol bis[(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate], 4,8-dioxa-1,11-undecanediol bis[(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate], 4,8-dioxa-1,11-undecanediol bis[(3'-tert-butyl-4'-hydroxy-5'-methylphenyl)propionate], 1,9-nonanediol bis[(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate] nate], 1,7-heptanediamine bis[3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionamide], 1,1-methanediamine bis[3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionamide], 3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionic acid hydrazide, 3-(3',5'-dimethyl-4'-hydroxyphenyl)propionic acid hydrazide, bis(3-tert-butyl-5-ethyl-2-hydroxyphen-1-yl)methane, bis(3,5-di-tert-butyl-4-hydroxyphen-1-yl)methane, bis[3-(1'-methylcyclohex-1'-yl)-5-methyl-2-hydroxyphen-1-yl]methane, bis(3-tert-butyl-2-hydroxy-5-methylphen-1-yl)methane, 1,1-bis(5-tert-butyl-4-hydroxy-2-methylphen-1-yl)ethane, bis(5-tert-butyl-4-hydroxy-2-methylphen-1-yl)sulfide, bis(3-tert-butyl-2-hydroxy-5-methylf 1,1-bis(3,4-dimethyl-2-hydroxyphen-1-yl)sulfide, 1,1-bis(3,4-dimethyl-2-hydroxyphen-1-yl)-2-methylpropane, 1,1-bis(5-tert-butyl-3-methyl-2-hydroxyphen-1-yl)butane, 1,3,5-tris-[1'-(3Δ,5”-di-tert-butyl-4”-hydroxyphen-1”-yl)meth-1'-yl]-2,4,6-trimethylbenzene, 1,1,4-tris(5'-tert-butyl-4'-hydroxy-2'-methylphen-1'-yl)butane and tert-butylcatecholate p-nitrosophenol, p-nitroso-o-cresol, methoxyphenol (guaiacol, pyrocatechol monomethyl ether), 2-ethoxyphenol, 2-isopropoxyphenol, 4-methoxyphenol (hydroquinone monomethyl ether), mono- or di-tert-butyl-4-methoxyphenol, 3,5-di-tert-butyl-4-hydroxyanisole, 3-hydroxy-4-methoxybenzyl alcohol, 2,5-dimethoxy-4-hydroxybenzyl alcohol, 4-hydroxy-3-methoxy Examples of suitable hydroxybenzaldehydes include 4-hydroxy-3-ethoxybenzaldehyde, 3-hydroxy-4-methoxybenzaldehyde, 1-(4-hydroxy-3-methoxyphenyl)ethanone, eugenol, dihydroeugenol, isoeugenol, tocopherols such as α-, β-, γ-, δ- and ε-tocopherol, tocol, α-tocopherol hydroquinone, 2,3-dihydro-2,2-dimethyl-7-hydroxybenzofuran (2,2-dimethyl-7-hydroxycoumaran), and combinations thereof.

[0042] Suitable quinones and hydroquinones include hydroquinone, hydroquinone monomethyl ether (4-methoxyphenol), methylhydroquinone, 2,5-di-tert-butylhydroquinone, 2-methyl-p-hydroquinone, 2,3-dimethylhydroquinone, trimethylhydroquinone, 4-methylpyrocatechol, tert-butylhydroquinone, 3-methylpyrocatechol, benzoquinone, 2-methyl-p-hydroquinone, 2,3-dimethylhydroquinone, tert-butylhydroquinone, 4-ethoxyphenol, 4-butoxyphenol, hydroquinone monobenzyl ether, p-phenoxyphenol, 2-methylhydroquinone, tetramethyl-p-benzoquinone, diethyl-1,4-cyclohexanedione 2,5-dicarboxylate, phenyl-p-benzoquinone, 2,5-dimethyl-3-benzyl-p-benzoquinone, 2-isopropyl-5-methyl-p-benzoquinone, Quinone (thymoquinone), 2,6-diisopropyl-p-benzoquinone, 2,5-dimethyl-3-hydroxy-p-benzoquinone, 2,5-dihydroxy-p-benzoquinone, embelin, tetrahydroxy-p-benzoquinone, 2,5-dimethoxy-1,4-benzoquinone, 2-amino-5-methyl-p-benzoquinone, 2,5-bisphenylamino-1,4-benzoquinone, 5,8-dihydroxy-1,4-naphthoquinone, 2-anilin No-1,4-naphthoquinone, anthraquinone, N,N-dimethylindoaniline, N,N-diphenyl-p-benzoquinone diimine, 1,4-benzoquinone dioxime, coellignon, 3,3'-di-tert-butyl-5,5'-dimethyldiphenoquinone, p-rosolic acid (aurin), 2,6-di-tert-butyl-4-benzylidenebenzoquinone, 2,5-di-tert-amylhydroquinone, and combinations thereof.

[0043] Suitable N-oxyl compounds (i.e., nitroxyl or N-oxyl groups) include compounds having at least one NO group, such as 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl, 4-oxo-2,2,6,6-tetramethylpiperidine-N-oxyl, 4-methoxy-2,2,6,6-tetramethylpiperidine-N-oxyl, 4-acetoxy-2,2,6,6-tetramethylpiperidine-N-oxyl, 2,2,6,6-tetramethylpiperidine-N-oxyl (tetramethylpiperidin-N-oxyl, T EMPO), 4,4',4"-tris(2,2,6,6-tetramethylpiperidine-N-oxyl)phosphite, 3-oxo-2,2,5,5-tetramethylpyrrolidine-N-oxyl, 1-oxyl-2,2,6,6-tetramethyl-4-methoxypiperidine, 1-oxyl-2,2,6,6-tetramethyl-4-trimethylsilyloxypiperidine, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl 2-ethylhexanoate, bis(2,2,6,6-tetramethylpiperidin-1-yl)oxyl sebacate, 1-oxy 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl stearate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl-benzoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl (4-tert-butyl)benzoate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) succinate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) adipate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) 1,10-decane dioate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) n-butyl malonate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) phthalate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) isophthalate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) terephthalate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) hexahydroterephthalate, N,N'-bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)adipamide, N-(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)caprolactam, N-(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)dodecylsuccinimide, 2,4,6-tris[N-butyl-N-(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl]triazine, N,N'-bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)-N,N'-bisformyl-1,6-diaminohexane, 4,4'-ethylenebis(1-oxyl-2,2,6,6-tetramethylpiperazin-3-one) and combinations thereof.

[0044] Other compounds suitable for use in or as an inhibitor include phenothiazine (PTZ) and compounds having a similar structure, such as phenoxazine, promazine, N,N'-dimethylphenazine, carbazole, N-ethylcarbazole, N-benzylphenothiazine, N-(1-phenylethyl)phenothiazine, N-alkylated phenothiazine derivatives such as N-benzylphenothiazine and N-(1-phenylethyl)phenothiazine, and combinations thereof. The inhibitor may be one of the compounds listed above or a combination of two or more different compounds. Alternatively, the inhibitor may comprise (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO), 4-hydroxy(2,2,6,6-tetramethylpiperidin-1-yl)oxyl (4HT), bis(2,2,6,6-tetramethylpiperidin-1-yl)oxyl sebacate (Bis-TEMPO), polymer-bound TEMPO, or combinations thereof.

[0045] The method may optionally include one or more additional steps. For example, the method may further include (2) recovering the ester-functional siloxane from the reaction product prepared in step (1). The recovering may be carried out by any convenient means, such as stripping and / or distillation, optionally under heating and / or vacuum. Without wishing to be bound by theory, it is believed that any unreacted starting material may be recycled in a subsequent reaction. Alternatively, the recovering may be carried out to separate the ester-functional siloxane and the platinum hydrosilylation reaction catalyst (or a complex of the catalyst and the promoter).

[0046] The ester-functional siloxanes prepared by this method have the unit formula (G1): (R 1 3 SiO 1 / 2 ) a (R 1 2 R 4 SiO 1 / 2 ) b (R 4 R 1 SiO 2 / 2 ) c (R 1 2 SiO 2 / 2 ) d (In the formula, R 1 and subscripts a, b, c, and d are as defined above; R 4 is the expression:

[0047] [ka] is a group of R 1 and R 2 is as defined above). EXAMPLES

[0048] These examples are intended to illustrate the invention to one of ordinary skill in the art and should not be construed as limiting the invention as set forth in the claims.

[0049] In this Reference Example 1, the platinum-catalyzed hydrosilylation reaction of allyl methacrylate with 1,1,1,3,5,5,5-heptamethyltrisiloxane (HMTS) to form 3-(1,1,1,3,5,5,5-heptamethyltrisiloxane-3-yl)propyl methacrylate (MD'M-ALMA) was investigated (see formula 1 above). The sample was prepared as follows. 2 In a loading glove box, 0.1 mL (0.01 mmol) of Karstedt's catalyst (2 wt% Pt in xylene solution, commercially available from Millipore Sigma, CAS number 2017-20-7) was loaded into a GC vial. When used, promoter was added to the catalyst solution to provide a 1:1 (Pt: promoter) ratio. The resulting catalyst solution was allowed to stand for 30 minutes before use. An appropriate volume of this catalyst solution (2 μL, 100 ppm) was then added to 1 mmol of allyl methacrylate (shown in Equation 1 as Substrate 1) (126 mg) and 800 ppm of TEMPO (used as inhibitor) in a 2-dram vial and heated to 50° C. 1.1 mmol of HMTS (245 mg) was slowly injected into the reaction vial. The reaction temperature was maintained at 50° C. and the GC-FID / 1 H NMR was monitored. Once GC-FID showed partial or complete consumption of substrate 1 (typically after 20-24 h), the heating block was removed and the resulting products were further analyzed by NMR spectroscopy.

[0050] The GC-FID conditions were as follows: GC-FID was performed on an Agilent 7890A equipped with an Agilent DB-5 capillary (15 m x 0.25 mm x 0.25 μm; length, ID, film). The method consisted of a 2 min hold at 50°C, followed by a 20 min -1 The temperature was raised to 250°C at 250°C and held at 250°C for 5 minutes.

[0051] [Table 1-1]

[0052] [Table 1-2]

[0053] Example 1 in Table 1 shows that the absence of a promoter resulted in poor selectivity under the conditions tested. The yield ratio of the desired product MD'M-ALMA produced relative to the oxy-silyl ester by-product was only 1.5:1. Furthermore, Examples 2 and 3 showed that comparative phosphine compounds such as those disclosed in U.S. Pat. No. 5,750,753 also promoted poor selectivity under the conditions tested.

[0054] In contrast, Examples 5 and 9 showed that dppm and dchpm all produced reaction products that had both 1) high selectivity to the desired product MD'M-ALMA (e.g., yield ratios of ≧3.4:1) and 2) good conversion of the starting material (e.g., ≧50%).

[0055] In this Example 2, the reaction described in Example 1 was carried out using different loadings of dppm and catalyst. The results are shown in Table 2 below.

[0056] [Table 2] a The remainder of the mass balance accounted for unreacted starting material, which was >90% converted to MD'M-ALMA after 24 h. b Only <2%-3% propylene hydrosilylation products were observed. c The reaction was completely stopped and all starting material was recovered after 24 hours.

[0057] The data in Table 2 showed that the amount of promoter can affect the yield and selectivity.

[0058] In this Reference Example 3, the hydrosilylation reaction of allyl acetate (6) with HMTS using a platinum catalyst and dppm to form 3-(1,1,1,3,5,5,5-heptamethyltrisiloxane-3-yl)propyl acetate (7) was investigated.

[0059] [ka]

[0060] The samples were prepared as follows: 2 In a packed glove box, 0.1 mL (0.01 mmol) of Karstedt's catalyst (2 wt% Pt in xylene solution, commercially available from Millipore Sigma, CAS number 2017-20-7) was loaded into a GC vial. An appropriate volume of diphenylphosphinomethane promoter (4.0 mg, 0.01 mmol) was added to the catalyst solution to give a (Pt:promoter) ratio ranging from 1:1 to 1:0.75. The catalyst solution was allowed to sit for 30 min before use. An appropriate volume (2 μL, 100 ppm) of this catalyst solution was then added to 1 mmol of allyl acetate (substrate 6) (100 mg) and 800 ppm of TEMPO (used as an inhibitor) in a 2-dram vial and heated to 50 °C. 1.1 mmol of HMTS (245 mg) was slowly injected into the vial. The reaction was maintained at 50 °C and analyzed by GC-FID / 1 The reaction was monitored by H NMR. Once GC-FID showed partial or complete consumption of allyl acetate (substrate 6), which typically required 20-24 h, the heating block was removed and the resulting products were further analyzed by NMR spectroscopy.

[0061] GC-FID conditions: GC-FID was performed on an Agilent 7890A equipped with an Agilent DB-5 capillary (15 m x 0.25 mm x 0.25 μm; length, ID, film). The method consisted of a 2 min hold at 50°C, followed by a 20 min -1 The temperature was raised to 250°C at 250°C and held at 250°C for 5 minutes.

[0062] [Table 3]

[0063] The results in Table 3 showed that the use of the dppm promoter was effective in producing the product in good yield (≧65%, higher than the no promoter control) and selectivity to 3-(1,1,1,3,5,5,5-heptamethyltrisiloxan-3-yl)propyl acetate under the conditions tested.

[0064] Industrial Applicability The method for preparing ester-functional siloxanes has advantages over previous methods that do not include promoters as described herein. The combination of advantages includes both 1) high selectivity to the desired ester-functional siloxanes (e.g., yield ratio of ester-functional siloxanes:oxy-silyl ester by-products of ≧2.5:1) and 2) good conversion of starting materials (e.g., ≧50%).

[0065] Definitions and Usage of Terms All amounts, ratios and percentages are by weight unless otherwise indicated. The Summary and Abstract of the Invention are incorporated herein by reference. The articles "a", "an" and "the" each refer to one or more, unless otherwise indicated by the context of the specification. The singular includes the plural, unless otherwise indicated. The terms "comprising" and derivatives thereof, such as "comprise" and "comprises", are used herein in their broadest sense to mean and encompass the notions of "including", "include", "consist(ing) essentially of", and "consist(ing) of". The use of "for example", "eg", "such as", and "including" to list examples is not limited to only the examples listed. Thus, "for example" or "such as" means "for example, but not limited to" or "such as, but not limited to," and includes other similar or equivalent examples.

[0066] It is to be understood that the appended claims are not limited to the specific compounds, compositions, or methods described therein for purposes of describing the "Description of the Invention" and may vary among specific embodiments within the scope of the appended claims. With respect to any Markush group relied upon in this specification to describe particular features or aspects of various embodiments, different, special, and / or unexpected results may result from each element of the respective Markush group independent of all other Markush elements. Each element of the Markush group may be relied upon individually and / or in combination to provide adequate support for specific embodiments within the scope of the appended claims.

[0067] Abbreviations used herein are defined in Table 4.

[0068]

Table 4

[0069] Embodiments of the present invention In the first embodiment, the method for preparing an ester-functional siloxane is (1) (A) A formula

[0070]

Chemical formula

[0071] [ka] (In formula, formula

[0072] [ka] is independently selected from the group consisting of cyclohexyl and phenyl; 6 is an independently selected alkyl group of 1 to 6 carbon atoms, and each subscript x is 0, 1, or 2; Combining starting materials comprising Includes.

[0073] In a second embodiment, in the method of the first embodiment, in the starting material (A), R 1 is methyl.

[0074] In a third embodiment, in the process of the first or second embodiment, the starting material (A) is allyl acetate.

[0075] In a fourth embodiment, in the method of the first embodiment, in the starting material (A), R 1 is the formula

[0076] [ka] is an alkenyl group.

[0077] In a fifth embodiment, in the method of the fourth embodiment, the starting material (B) is allyl methacrylate.

[0078] In a sixth embodiment, in the method of the first embodiment, in the starting material (A), R 1 is the formula

[0079] [ka] is an alkenyl group.

[0080] In a seventh embodiment, in the method of the sixth embodiment, the starting material (A) is allyl acrylate.

[0081] In an eighth embodiment, in the method of the first embodiment, the starting material (A) has the formula

[0082] [ka] (In the formula, R 5 is selected from the group consisting of H, alkyl and aryl; R 3 is selected from the group consisting of H, alkyl, and aryl; R 4 is selected from the group consisting of H, alkyl, and aryl.

[0083] In a ninth embodiment, in the method of any one of the first to eighth embodiments, the starting material (B) is represented by the formula (B4):

[0084] [ka] (In the formula, R 1 is as above).

[0085] In a tenth embodiment, in the method according to any one of the first to eighth embodiments, the starting material (B) is represented by the formula (B5):

[0086] [ka] In the formula, R 1 is as above).

[0087] In an eleventh embodiment, in the method of the ninth embodiment or the tenth embodiment, each R in formula (B4) and formula (B5) 1 is methyl.

[0088] In a twelfth embodiment, in the method of any one of the first to eleventh embodiments, the starting material (C) includes a platinum vinyldimethylsiloxane complex.

[0089] In a thirteenth embodiment, in the method of any one of the first to twelfth embodiments, the method further comprises combining (C) a platinum hydrosilylation reaction catalyst and (D) an accelerator prior to step (1).

[0090] In a fourteenth embodiment, in the method of the thirteenth embodiment, combining (C) the platinum hydrosilylation reaction catalyst with (D) the promoter is conducted in (E) a solvent.

[0091] In a fifteenth embodiment, in the process of any one of the first to fourteenth embodiments, the amount of starting material (D) promoter is >0.5 moles to <1.25 moles per mole of platinum.

[0092] In a sixteenth embodiment, in the method of any one of the first to fifteenth embodiments, (D) the promoter is selected from the group consisting of (D1) bis(diphenylphosphino)methane, (D2) bis(dicyclohexylphosphino)methane, and (D3) a combination of both (D1) and (D2).

[0093] In a seventeenth embodiment, in the method of any one of the first to sixteenth embodiments, the (D) accelerator is (D1) bis(diphenylphosphino)methane.

[0094] In an eighteenth embodiment, in the method of any one of the first to sixteenth embodiments, the (D) promoter is (D2) bis(dicyclohexylphosphino)methane.

[0095] In a nineteenth embodiment, in the method of any one of the first to eighteenth embodiments, the amount of the promoter (D) is 0.75 moles to 1 mole per mole of platinum.

[0096] In a twentieth embodiment, the method of any one of the first to nineteenth embodiments further comprises adding (F) a (meth)acrylate polymerization inhibitor.

[0097] In a twenty-first embodiment, the method of any one of the first to twentieth embodiments further comprises recovering the ester functional siloxane after step (1).

[0098] In a twenty-second embodiment, in the method of any one of the first to twenty-first embodiments, the ester-functional siloxane is represented by the unit formula: (R 1 3 SiO 1 / 2 ) a (R 1 2 R 4 SiO 1 / 2 ) b (R 4 R 1 SiO 2 / 2 ) c (R 1 2 SiO 2 / 2 ) d (In the formula, each R 1 and subscripts a, b, c, and d are as defined above, and each R 4 is the formula

[0099] [ka] where R 1 and R 2 is as above).

[0100] In a twenty-third embodiment of the method of the twenty-second embodiment, the ester functional siloxane is 3-(1,1,1,3,5,5,5-heptamethyltrisiloxane-3-yl)propyl methacrylate.

[0101] In a twenty-fourth embodiment, in the method of the twenty-second embodiment, the ester functional siloxane is 3-(1,1,1,3,5,5,5-heptamethyltrisiloxane-3-yl)propyl acrylate.

[0102] In a twenty-fifth embodiment, in the method of the twenty-second embodiment, the ester functional siloxane is 3-(1,1,1,3,5,5,5-heptamethyltrisiloxane-3-yl)propyl acetate.

Claims

1. A method for preparing ester-functionalized siloxanes, （１） (A) Formula 【Chemistry 1】 (In the formula, R １ R is a monovalent hydrocarbon group consisting of 1 to 12 carbon atoms. ２ (Selected from the group consisting of hydrogen and alkyl groups with 1 to 12 carbon atoms.) alkenyl esters, (B) Unit formula (R １ ３ SiO １／２ ) ａ (R １ ２ HSiO １／２ ) ｂ (HR １ SiO ２／２ ) ｃ (R １ ２ SiO ２／２ ) ｄ (In the formula, each R １ (a + b + c + d) is a monovalent hydrocarbon group consisting of 1 to 12 independently selected carbon atoms, where the subscripts a, b, c, and d represent the average number of units in the unit formula, and have values ​​such that 0 ≤ a ≤ 2, 0 ≤ b ≤ 2, 0 ≤ c ≤ 3, 0 ≤ d ≤ 3, the amount of (a + b) = 2, the amount of (b + c) ≥ 1, and the amount of (a + b + c + d) is between 2 and 10. Organohydrogensiloxane oligomer, Here, (A) the alkenyl ester and (B) the organohydrogensiloxane oligomer are present in amounts such that the molar ratio (B):(A) of (B) the organohydrogensiloxane oligomer to (A) the alkenyl ester (B) is 1.25:1 to 0.75:

1. (C) Platinum hydrosilylation reaction catalyst, and A sufficient amount of formula (D) to provide both a yield ratio of ≥2.5:1 for the ester-functionalized siloxane:oxysilyl ester byproduct and a conversion rate of ≥50% for the starting materials (A) and (B). 【Chemistry 2】 (In formula, formula 【Transformation 3】 Each group is independently selected from the group consisting of cyclohexyl and phenyl, and each R ６ (where x is an independently selected alkyl group of 1 to 6 carbon atoms, and each subscript x is independently 0, 1, or 2) as an accelerator. Combine the starting materials that include Methods that include...

2. In the starting materials (A), R １ The method according to claim 1, wherein is methyl.

3. In the starting materials (A), R １ However, the formula 【Chemistry 4】 The method according to claim 1, wherein the alkenyl group is...

4. In the starting materials (A), R １ However, the formula 【Transformation 5】 The method according to claim 1, wherein the alkenyl group is...

5. Starting material (B) is, 【Transformation 6】 The method according to any one of claims 1 to 4, comprising:

6. Each R １ The method according to claim 5, wherein the substance is methyl.

7. The method according to any one of claims 1 to 4, wherein the starting material (C) comprises a platinum vinyl dimethylsiloxane complex.

8. The method according to any one of claims 1 to 4, further comprising combining (C) the platinum hydrosilylation catalyst and (D) the accelerator before step (1).

9. The method according to claim 8, wherein (C) the platinum hydrosilylation reaction catalyst and (D) the accelerator are combined in (E) a solvent.

10. The amount of starting material (D) is greater than 0.5 moles but less than 1.25 moles per mole of platinum, and the amount of starting material (D) (D1) Bis(diphenylphosphin)methane, (D2) Bis(dicyclohexylphosphino)methane, and (D3) Selected from the group consisting of combinations of both (D1) and (D2), The method according to any one of claims 1 to 4.

11. The method according to claim 10, wherein the accelerator is (D1) bis(diphenylphosphin)methane.

12. The method according to claim 10, wherein the accelerator is (D2) bis(dicyclohexylphosphino)methane.

13. The method according to any one of claims 1 to 4, wherein the amount of the accelerator (D) is 0.75 moles to 1 mole per mole of platinum.

14. (F) The method according to any one of claims 1 to 4, further comprising adding a (meth)acrylate polymerization inhibitor.

15. The method according to any one of claims 1 to 4, further comprising (2) recovering the ester-functionalized siloxane after step (1).

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