WO2024238030A1

WO2024238030A1 - Process for making cyanoethyltrimethoxysilane and dimer

Info

Publication number: WO2024238030A1
Application number: PCT/US2024/022600
Authority: WO
Inventors: Michael DEPIERRO; James CHARBONNEAU; Xiaoyuan Zhou
Original assignee: Dow Silicones Corp
Current assignee: Dow Silicones Corp
Priority date: 2023-05-16
Filing date: 2024-04-02
Publication date: 2024-11-21
Anticipated expiration: 2025-11-16
Also published as: CN121079305A

Abstract

A process for preparing a reaction product including cyanoethyltrimethoxysilane and a dimer is performed via reaction of cyanoethyltriethoxysilane with methanol and water in the presence of a catalyst. The reaction product is useful as an adhesion promoter, a coupling agent, or a crosslinker. The reaction product may be formulated in a polyorganosiloxane sealant composition.

Description

PROCESS FOR MAKING CYANOETHYLTRIMETHOXYSILANE AND DIMER

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63/466,735 filed on May 16, 2024 under 35 U.S.C. §119 (e). U.S. Provisional Patent Application Serial No. 63/466,735 is hereby incorporated by reference.

FIELD

[0002] This invention pertains to a process for making a reaction product comprising cyanoethyltrimethoxysilane and a dimer thereof. This invention further pertains to a polyorganosiloxane composition containing said reaction product.

INTRODUCTION

[0003] U.S. Patent 3,008,975 discloses a process for preparing silicon esters from halosilanes. . . . [S]ilicon esters are produced by forming a mixture of a halosilane and an alcohol, reducing the pressure on said mixture to about 200 mm. Hg absolute pressure, and maintainings aid mixture at a temperature at which the halosilane and alcohol react in the liquid phase to produce a silicon ester. . . . [O]ne by-product of the esterification is water. Water is a highly undesirable by-product since it hydrolyzes the halosilane present in the system to produce undesirable polysiloxanes, and combines with hydrogen halide to produce hydrohalic acid, which attachks certain acid-sensitive groups which may be present on the silane . . . and catalyzes other undesirable side reactions. . . . It is therefore desirable to remove water from the reaction system.

[0004] Cyanoethyltrimethoxysilane (CETMS) is useful as an adhesion promoter or a coupling agent in siloxane compositions, such as room temperature vulcanizable (RTV) polyorganosiloxane sealant compositions. CETMS can be made via hydrosilylation reaction of acrylonitrile with trichlorosilane followed by methoxylation. CETMS can also be made by the hydrosilylation reaction of trimethoxy silane with acrylonitrile. However, these processes suffer from drawbacks with the result that CETMS is not widely available on a commercial scale.

SUMMARY

[0005] A process for making a reaction product comprising an alkoxysilane product and a dimer (composition) comprises combining cyanoethyltriethoxysilane, methanol, water, and an acid catalyst. The composition is useful in a polyorganosiloxane composition.

DETAILED DESCRIPTION

[0006] More specifically, the process for making the reaction product comprising the alkoxy silane product and the dimer (composition) comprises:

1) combining starting materials comprising (A) cyanoethyl triethoxysilane (CETES), (B) the methanol, in a stoichiometric excess, (C) water, and (D) an acid catalyst; thereby producing a reaction mixture; optionally 2) adding (E) activated carbon to the reaction mixture;

3) removing materials comprising methanol, ethanol and (D) the acid catalyst from the reaction mixture; and

4) repeating steps 1) to 3) one or more times (for a total of at least two additions of (B) methanol, (C) water, and (D) acid catalyst and subsequent removal of methanol, ethanol, and catalyst), thereby forming the composition.

[0007] In this process, transesterification reaction of CETES and methanol and hydrolysis reaction to form dimer may proceed according to the reaction scheme shown below.

In the formula for the Alkoxysilane Product, when x = 0 the formula is CETMS. However, partially methoxylated species, e.g., cyanoethyl-, diethoxy-, monomethoxy- silane (where x = 2) and/or cyanoethyl-, monoethoxy-, dimethoxy- silane (where x = 1), may also form during the process described herein. Therefore, subscript x may have a value of 0 to 2, alternatively 0 to 1, and alternatively 0. In the formula for the Dimer in this reaction scheme, each R is independently selected from the group consisting of methyl and ethyl. Alternatively, each R may he methyl. It is desirable to drive the reactions to a high conversion of the ethoxy groups in the CETES to methoxy groups and an amount of Dimer formation that improves one or more properties of a polyorganosiloxane composition and/or the cured product thereof, when the reaction product is used in the polyorganosiloxane composition.

[0008] In step 1) of the process described herein, (A) the cyanoethyltriethoxysilane and (B) the methanol are used in amounts sufficient to provide a stoichiometric excess of methanol. The amounts of (A) the cyanoethyltriethoxysilane and (B) the methanol may be at least 5:1 (B):(A) (molar ratio), alternatively at least 15: 1, while at the same time (B):(A) may be up to 30: 1, alternatively up to 15:1. Alternatively, (B):(A) may be 5: 1 to 30: 1, alternatively > 5: 1 to 30: 1, and alternatively 15: 1 to 30:1.

[0009] Without wishing to be bound by theory, it is thought that Step 1) may be performed at RT or elevated temperature, such as up to 70 °C. Alternatively, temperature may be 21 °C to 70 °C. Time for the transesterification reaction in step 1) is sufficient to reach equilibrium. For example, at RT the time may be 1 hour to 4 hours. However, the exact time will depend on various factors such as the temperature selected and the selection and amounts of (C) water and (D) the acid catalyst. Without wishing to be bound by theory, it is thought that performing step 1) at RT may be efficient in terms of time, energy, and cost associated with heating and cooling. The use of the acid catalyst may provide the benefit of enabling a fast reaction at RT, which minimizes time and operating cost. The reaction may be optionally carried out at elevated temperatures.

[0010] Starting material (C), the water, is not generally limited, and may be pure (i.e., free from, or substantially free from, minerals and/or other impurities). Alternatively, the water may be processed or unprocessed before its addition in step 1), described above. Examples of processes that may be used for purifying the water include distilling, filtering, deionizing, and combinations of two or more thereof, such that the water may be deionized, distilled, and/or filtered. Alternatively, the water may be unprocessed (e.g., may be tap water, i.e., provided by a municipal water system or well water, used without further purification).

[0011] The water may be utilized in an amount, which will be selected by one of skill in the art, depending on various factors, e.g., the desired amount of Dimer to be formed in the reaction product, the reaction parameters employed, the scale of the reaction, and the species of (D) the acid catalyst selected. However the amount of (C) the water may be 0.05% to 1% based on weight of (B) the methanol.

[0012] Starting material (D), the acid catalyst, may be selected from the group consisting of a hydrogen halide, e.g., of formula HX, where X is Cl, Br, or I; a sulfonic acid (such as toluene sulfonic acid or trifluoromethane sulfonic acid); and an ion exchange resin. Alternatively, (D) the acid catalyst may be the hydrogen halide, and alternatively the acid catalyst may be HC1. When (D) the acid catalyst is the hydrogen halide, e.g., HC1, the hydrogen halide (e.g., HC1) may be used in an amount of at least 1 ppm, alternatively at least 5 ppm, alternatively at least 10 ppm, alternatively at least 30 ppm, while at the same time the amount of hydrogen halide (e.g., HC1) may be up to 100 ppm, alternatively up to 50 ppm, alternatively up to 30 ppm, based on weight of (A) the CETES and weight of (B) the MeOH combined. Alternatively, the amount of hydrogen halide (e.g., HC1) may be 10 ppm to 100 ppm, alternatively 10 ppm to 50 ppm, and alternatively 30 ppm, on the same basis. Alternatively, when the ion exchange resin is used, the amount may be at least 0.1% of solid to liquid, alternatively at least 0.5% while at the same time the amount may be up to 30%, on the same basis. Alternatively, the amount of ion exchange resin may be 0.1% to 30% on the same basis.

[0013] The starting materials used in the step 1) of the process are known in the art and are commercially available. CETES is available from Gelest Inc. of Morrisville, Pennsylvania, USA. MeOH and HC1 are available from various sources including Sigma- Aldrich, Inc. of St. Louis, Missouri, USA. Ion exchange resins may be strong and weak acid cation exchange resins where the ionic form of the resin is not hydrogen (H+) for use herein. Such ion exchange resins are commercially available, for example, DOWEX™ Monosphere 2030, DOWEX™ MARATHON™ 1200 (Na+ form), and AMBERLITE IR122 Na are commercially available from TDCC.

[0014] Combining the starting materials in step 1) may be performed batchwise or continuously and by any convenient means, such as mixing. Mixing may be performed in conventional equipment, such as a batch reactor equipped with an agitator and optionally heating means, such as a jacket. For example, when step 1) is performed in a batch mode, (A) the CETES may be placed in the reactor, optionally under agitation. All or a portion of (B) the methanol may then be added to the reactor. Next, (C) the water may be added to the reactor. Next, (D) the acid catalyst may be added to the reactor. The acid catalyst may be added to the reactor neat. Alternatively, a portion of (B) the methanol and (D) the acid catalyst may be combined to form a catalyst solution, which is added to the reactor.

[0015] Alternatively, the process may be performed in packed bed reactor, e.g., where the reactor may be packed with (D) the acid catalyst when a solid catalyst is used, e.g., the ion exchange resin, and/or when step 2) is present, e.g., activated carbon is used.

[0016] Step 2) of the process comprises combining (E) activated carbon and the reaction mixture prepared in step 1). Step 2) is optional. However, when used, step 2) may be performed at RT, for example, by mixing the activated carbon with the reaction mixture prepared in step 1) for a time sufficient to adsorb acid HC1 therefrom. The exact time depends on various factors, such as size of the vessel used for step 2), (which may be the same as the reactor used in step 1),) however, the time may be at least 1 hour, alternatively at least 2 hours, alternatively at least 4 hours, alternatively at least 8 hours, and alternatively at least 16 hours; while concurrently the time may be up to 48 hours, alternatively up to 24 hours, and alternatively up to 16 hours. Step 2) may be performed under conditions that minimize or eliminate moisture.

[0017] When step 2) is present, (E) the activated carbon may be selected from the group consisting of (El) bituminous coal activated carbon, (E2) coconut activated carbon with an iodine number > 1200 mg/g, and (E3) a combination of both (El) and (E2). The (El) bituminous coal activated carbon and (E2) coconut activated carbon are known in the art and are commercially available from various sources, such as General Carbon Corporation of Paterson, New Jersey, USA, or Calgon Carbon of Pittsburgh, Pennsylvania, USA. The bituminous coal activated carbon may have an iodine number of at least 500 mg/g (min), alternatively at least 600 mg/g (min), alternatively at least 750 mg/g (min), alternatively at least 850 mg/g (min), alternatively at least 900 mg/g (min), while at the same time the bituminous coal activated carbon may have an iodine number up to 1200 mg/g (min), alternatively up to 1,100 mg/g (min), alternatively up to 1,000 mg/g (min), and alternatively up to 950 mg/g (min). Alternatively, iodine number of the bituminous coal activated carbon may be 600 mg/g (min) to 1200 mg/g (min), alternatively 750 mg/g (min) to 1200 mg/g (min), 900 mg/g (min) to 1200 mg/g (min), and alternatively 900 mg/g (min) to 1050 mg/g (min). Iodine number of the coconut activated carbon may be > 1200 mg/g (min), alternatively 1,200 mg/g (min) to 1,500 mg/g (min), and alternatively 1,200 mg/g (min) to 1,300 mg/g (min).

[0018] Examples of bituminous coal activated carbon include GC 12x40, which is a virgin activated carbon which is granular in form with an iodine number of 900 mg/g (min) and a density of 0.47 to 0.53 g/cc and which is commercially available from General Carbon Corporation; and CAL™ 12x40 granular activated carbon, which is reagglomerated metallurgical grade bituminous coal with an iodine number of 1000 mg/g (min), and which is commercially available from Calgon Carbon. Other bituminous coal activated carbons from Calgon Carbon include CPG™ LF 12 x 40, which has an iodine number of 950 mg/g (min); FILTRASORB™ 300M, which has an iodine number of 900 mg/g (min); FILTRASORB™ 400M, which has an iodine number of 1000 mg/g (min); HPC MAXX, which has an iodine number 900 mg/g; and SGL 8 x 20, which is a granular activated carbon made from bituminous coal combined with binders and having iodine number 900 (min) mg/g. Coconut activated carbons include OLC Plus 12x30, which has an iodine number of 1200 mg/g (min) and a density of 0.45 g/cc, and OLC Plus 12x30 is also available from Calgon Carbon.

[0019] When step 2) is present (i.e., the activated carbon is used), the activated carbon may be treated or untreated before use. Water adsorbed in the activaed carbon may form additional Dimer. Alternatively, the process may further comprise treating the activated carbon before use in step 2). Treating may be performed, e.g., to dry the activated carbon (e.g., remove all or a portion of any adsorbed moisture to minimize potential for hydrolysis of the Alkoxysilane Product when the carbon contacts the transesterification reaction mixture). For example, the activated carbon may be heated to a temperature above the boiling point of water (e.g., > 100 °C, alternatively > 100 °C to 200 °C, alternatively 120 °C to 160 °C) for a time sufficient to remove all or a portion of the water, e.g., 1 minute to 24 hours. The activated carbon may be heated at ambient or reduced pressure. The activated carbon may be heated and stored under an inert atmosphere, such as nitrogen, before use in step 2) such that the amount of water used in the process to form Dimer is controlled.

[0020] Step 3) of the process comprises removing materials comprising (excess) unreacted (B) methanol, ethanol (which is produced as a side product), and (D) the acid catalyst from the reaction mixture. Step 3) may be performed by any convenient means. Step 3) may comprise filtration, e.g., to remove solid materials, such as ion exchange resin, when used as (D) the acid catalyst, and/or activated carbon, when step 2) is present. Step 3) may also comprise stripping and/or distillation with heating and optionally with reduced pressure, which can remove methanol, ethanol, and liquid acid catalysts, such as HC1.

[0021] Step 4) of the process comprises repeating steps 1) to 3) one or more times. Step 4) may comprise repeating 1) to 3) at least one time, alternatively one to four times. Without wishing to be bound by theory, it is thought that repeating steps 1) to 3) too many times (e.g., five or more times (alternatively 5 or more times), for a total of six to seven, or more, additions of water, methanol, and acid catalyst and subsequent removals, may result in increased costs that make the process impractical on a commercial scale. Alternatively, step 4) may comprise repeating steps 1) to 3) one or two times, particularly when step 2) is present. Without wishing to be bound by theory, it is thought that due to thermodynamic equilibrium limitations and higher volatility of methanol than ethanol, during step 3), (e.g., via stripping and/or distillation) a reverse reaction can occur via reaction of the CETMS (where x = 0 in the formula for the Alkoxylated Product shown above) or partially the methoxylated species (where x = 1 or 2) with the EtOH side product, which cannot be removed until all or a significant portion of the lower boiling point MeOH is first removed. Without wishing to be bound by theory, it is thought that treating the reaction mixture with activated carbon in step 2) may minimize this reverse reaction. Because each repetition of steps 1) to 3) can add cost to the process, it is desirable to minimize the number of repetitions in step 4) for efficiency, provided yield and purity of the reaction product is achieved.

[0022] The process described above may optionally further comprise one or more additional steps. For example, after step 4), the process may further comprise: 5) treating the reaction product with activated carbon. Without wishing to be bound by theory, step 5) may be performed by pumping the reaction product through a vessel, such as a drum or bed, that contains activated carbon, or the activated carbon may be added to the vessel used in step 4) and thereafter filtered out of the product. The activated carbon used in step 5) may be the as described above with respect to step 2). When step 5) is present, the process may optionally further comprise drying the activated carbon before use.

[0023] The process described above produces a composition comprising

Alternatively, each R may be methyl. Alternatively, each x may be 0. Alternatively, the composition may comprise: cyanoethyltrimethoxysilane (CETMS), which has formula:

v y, p n may consist essentially of CETMS and the dimer thereof. Alternatively, the composition may consist of CETMS and the dimer thereof. Alternatively, the composition may be substantially free of, or free of, methoxy groups in the alkoxysilane product and the dimer. In the process described above, conversion of the ethoxy groups of the CETES starting material to methoxy groups may be at least 90 GC area %, alternatively at least 91 GC area %, alternatively at least 92 GC area %, alternatively at least 93 GC area %, and alternatively at least 94 GC area %, while at the same time, the conversion may be up to 100 GC area %, alternatively up to 99 GC area %, alternatively up to 98 GC area %, alternatively up to 97 GC area %, and alternatively up to 96 GC area %, as measured by the test method described below and used in the examples. Purity of the CETMS may be at least 72 GC area %, alternatively at least 81 GC area %, alternatively at least 86 GC area %, alternatively at least 89 GC area %, and alternatively at least 90 GC area %, while at the same time purity of the CETMS may be up to 100 GC area %, alternatively up to 98 GC area %, alternatively up to 95 GC area %, alternatively up to 92 GC area %, and alternatively up to 90 GC area %, as measured by the test method described below and used in the examples. The amount of Dimer may be at least 20 wt% (based on combined weights of Alkoxysilane Product and Dimer), alternatively 20 wt% to 30 wt %, alternatively 20 wt% to 29 wt%, alternatively 20 wt% to 28 wt%, alternatively 20 wt % to 27 wt%, and alternatively 20 to 26 wt%, on the same basis.

[0024] The reaction product produced as described above may be used in a polyorganosiloxane composition, such as a room temperature vulcanizable organopolysiloxane composition. RTV organopolysiloxane compositions are known in the art, such as those disclosed in U.S. Patent 4,483,973 to Lucas, et al.; U.S. Patent 5,962,559 to Lucas, et al.; U.S. Patent 7,550,548 to Hatanaka, et al.; U.S. Patent 7,674,871 to Koch, et al.; U.S. Patent Application Publication 2007/0173597 to Williams, et al.; and PCT Patent Application Publication W02007/024792. The reaction product comprising the CETMS and the Dimer may function as an adhesion promoter, a coupling agent, and/or a crosslinking agent in a polyorganosiloxane composition. Alternatively, the reaction product may be added to a commercially available RTV sealant, such as XIAMETER™ SLT-5200 from DSC. Without wishing to be bound by theory, it is thought that the polyorganosiloxane composition containing the reaction product prepared as described herein may superior adhesion to a comparative polyorganosiloxane composition that does not contain CETMS or that contains CETMS with a lower level of Dimer than that described herein.

EXAMPLES

[0025] These examples are intended to illustrate the invention to one skilled in the art and are not to be construed so as to limit the invention set forth in the claims. Materials used herein are described in Table 1.

Table 1

Example 1 (Comparative) [0026] CETMS 1 was purchased from MPM. The CETMS 1 contained 2 wt% Dimer measured by GC.

Example 2 - Dow CETMS 2 (Comparative)

[0027] Cyanoethyltrimethoxysilane (CETMS) was synthesized by the following method. 3299g of methanol was added to 1514g of cyanoethyltriethoxysilane (CETES) in a 7L glass reactor under agitation. Then, 1.50mL of 3M HC1 in methanol was added to the reactor. Reaction was completed after 1 hour at room temperature. The reaction mixture was then distilled to remove methanol and ethanol under 75-150 mmHg vacuum while heated to 30-60°C prior to addition of new methanol.

[0028] The partially reacted CETES recovered from distillation was then reacted in a second cycle. To the reaction mix 3265 g of methanol was added to the mixture. The reaction mix was stirred for 1 hour at room temperature. The reaction mixture was then distilled to remove methanol and ethanol under 75-150 mmHg vacuum while heated to 30-60°C prior to addition of new methanol.

[0029] The partially reacted CETES recovered from distillation was then reacted in a third cycle. To the reaction mix 3301 g of methanol was added to the mixture. The reaction mix was stirred for 1 hour at room temperature. The reaction mixture was then distilled to remove methanol and ethanol under 75-150 mmHg vacuum while heated to 30-60°C prior to addition of new methanol.

[0030] The partially reacted CETES recovered from distillation was then reacted in a fourth cycle. To the reaction mix 3352 g of methanol was added to the mixture. The reaction mix was stirred for 1 hour at room temperature. The reaction mixture was then distilled to remove methanol and ethanol under 75-150 mmHg vacuum while heated to 30-60°C.

[0031] The final CETMS product recovered after distillation was then neutralized with 25 wt% sodium methoxide in methanol then filtered. 1047 g of final CETMS product was recovered. The CETMS product was measured by GC to be 89.7% CETMS, 5.0% cyanoethyldimethoxymonoethoxysilane (CE2M1ES), 0.1% cyanoethylmonomethoxydiethoxysilane (CE1M2ES), 1.1 % methanol, and 4.0% dimer by weight.

Example 3 - Reaction Product Produced by the Process Herein

[0032] Cyanoethyltrimethoxysilane (CETMS) was synthesized by the following method. 3271 g of methanol was added to 1480 g of cyanoethyltriethoxysilane (CETES) in a 7L glass reactor under agitation. Next, 7.3 g of deionized water was added to the reactor. Then, 2.0 mL of 3M HC1 in methanol was added to the reactor. Reaction was completed after 1 hour at room temperature. The reaction mixture was then distilled to remove methanol and ethanol under 75- 150 mmHg vacuum while heated to 30-60°C prior to addition of new methanol.

[0033] The partially reacted CETES recovered from distillation was then reacted in a second cycle. To the reaction mix 3244 g of methanol, 7.4 g of water was added to the mixture. The reaction mix was stirred for 1 hour at room temperature. The reaction mixture was then distilled to remove methanol and ethanol under 75-150 mmHg vacuum while heated to 30-60°C prior to addition of new methanol.

[0034] The partially reacted CETES recovered from distillation was then reacted in a third cycle. To the reaction mix 3269 g of methanol, 7.75 g of water was added to the mixture. The reaction mix was stirred for 1 hour at room temperature. The reaction mixture was then distilled to remove methanol and ethanol under 75-150 mmHg vacuum while heated to 30-60°C prior to addition of new methanol.

[0035] The partially reacted CETES recovered from distillation was then reacted in a fourth cycle. To the reaction mix 3289 g of methanol, 7.5 g of water was added to the mixture. The reaction mix was stirred for 1 hour at room temperature. The reaction mixture was then distilled to remove methanol and ethanol under 75-150 mmHg vacuum while heated to 30-60°C.

[0036] The final CETMS product recovered after distillation was then neutralized with 25 wt% sodium methoxide in methanol then filtered. 1051 g of final CETMS product was recovered. The CETMS product was measured by GC to be 76. 1% CETMS, 3.6% cyanoethyldimethoxymonoethoxysilane (CE2M1ES), 3.8% methanol, and 20.2% dimer by weight.

Example 4 - Reaction Product Produced by the Process Herein

[0037] Cyanoethyltrimethoxysilane (CETMS) was synthesized by the following method. 3273 g of methanol was added to 1441 g of cyanoethyltriethoxysilane (CETES) in a 7L glass reactor under agitation. Next, 5.0 g of deionized water was added to the reactor. Then, 1.32mL of 3M HC1 in methanol was added to the reactor. Reaction was completed after 1 hour at room temperature. The reaction mixture was then distilled to remove methanol and ethanol under 75- 150 mmHg vacuum while heated to 30-60°C prior to addition of new methanol.

[0038] The partially reacted CETES recovered from distillation was then reacted in a second cycle. To the reaction mix 3158 g of methanol, 5.5 g of water was added to the mixture. The reaction mix was stirred for 1 hour at room temperature. The reaction mixture was then distilled to remove methanol and ethanol under 75-150 mmHg vacuum while heated to 30-60°C prior to addition of new methanol.

[0039] The partially reacted CETES recovered from distillation was then reacted in a third cycle. To the reaction mix 3307 g of methanol, 5.0 g of water was added to the mixture. The reaction mix was stirred for 1 hour at room temperature. The reaction mixture was then distilled to remove methanol and ethanol under 75-150 mmHg vacuum while heated to 30-60°C prior to addition of new methanol.

[0040] The partially reacted CETES recovered from distillation was then reacted in a fourth cycle. To the reaction mix 3282 g of methanol, 5.0 of water was added to the mixture. The reaction mix was stirred for 1 hour at room temperature. The reaction mixture was then distilled to remove methanol and ethanol under 75-150 mmHg vacuum while heated to 30-60°C prior to addition of new methanol.

[0041] The partially reacted CETES recovered from distillation was then reacted in a fifth cycle. To the reaction mix 3282 g of methanol, 16.1 g of water was added to the mixture. The reaction mix was stirred for 1 hour at room temperature. The reaction mixture was then distilled to remove methanol and ethanol under 75-150 mmHg vacuum while heated to 30-60°C.

[0042] The final CETMS product recovered after distillation was then neutralized with 25 wt% sodium methoxide in methanol then filtered. 1031 g of final CETMS product was recovered. The CETMS product was measured by GC to be 71.4% CETMS, 2.3% cyanoethyldimethoxymonoethoxysilane (CE2M1ES), 3.7% methanol, and 26.3% dimer by weight.

Example 5 - Reaction Product Produced by the Process Herein

[0043] Cyanoethyltrimethoxysilane (CETMS) was synthesized by the following method. 3526 g of methanol was added to 1595 g of cyanoethyltriethoxysilane (CETES) in a 7L glass reactor under agitation. Next, 2.8 g of deionized water was added to the reactor. Then, 1.50 mL of 3M HC1 in methanol was added to the reactor. Reaction was completed after 1 hour at room temperature. The reaction mixture was then distilled to remove methanol and ethanol under 75- 150 mmHg vacuum while heated to 30-60°C prior to addition of new methanol.

[0044] The partially reacted CETES recovered from distillation was then reacted in a second cycle. To the reaction mix 3594 g of methanol, 2.7 g of water was added to the mixture. The reaction mix was stirred for 1 hour at room temperature. The reaction mixture was then distilled to remove methanol and ethanol under 75-150 mmHg vacuum while heated to 30-60°C prior to addition of new methanol.

[0045] The partially reacted CETES recovered from distillation was then reacted in a third cycle. To the reaction mix 3642 g of methanol, 2.8 g of water was added to the mixture. The reaction mix was stirred for 1 hour at room temperature. The reaction mixture was then distilled to remove methanol and ethanol under 75-150 mmHg vacuum while heated to 30-60°C prior to addition of new methanol. [0046] The partially reacted CETES recovered from distillation was then reacted in a fourth cycle. To the reaction mix 3601 g of methanol, 2.8 g of water was added to the mixture. The reaction mix was stirred for 1 hour at room temperature. The reaction mixture was then distilled to remove methanol and ethanol under 75-150 mmHg vacuum while heated to 30-60°C.

[0047] The final CETMS product recovered after distillation was then neutralized with 25 wt% sodium methoxide in methanol then filtered. 1197 g of final CETMS product was recovered. The CETMS product was measured by GC to be 85.4% CETMS, 4.0% cyanoethyldimethoxymonoethoxy silane (CE2M1ES), 0.1% cyanoethylmonomethoxydiethoxysilane (CE1M2ES), 0.9% methanol, and 9.6% dimer by weight.

Reference Example 6

[0048] In this Reference Example, the materials prepared as described above in Examples 1-4 were tested as adhesion promoters in a curable polyorganosiloxane composition (sealant). Adhesion peel testing was performed as described below. The results are shown below in Table 2.

Table 2 - Results

[0049] The results in Table 2, above, show that adhesion is improved when the reaction product including 20 wt% to 26 wt% Dimer (balance CETMS based on combined weights of CETMS and Dimer) is used in a curable polyorganosiloxane composition, as compared to the same composition but using CETMS containing lower amounts of Dimer (2 wt% to 4 wt%). Specifically, after immersion in water, the adhesion peel strength (pli) was higher for the samples made with CETMS containing 20% Dimer or 26% Dimer as compared to the samples with 2% Dimer or 4% Dimer.

Test Methods

[0050] Gas Chromatography (GC) was used to verify composition of material with internal standard composition of lwt% nonane in acetonitrile. All reported compositions are based on GC area % unless otherwise indicated. An Agilent 7890A GC System with helium carrier gas and an FID detector was used with Restek Rtx- 1 30m x 0.25 mm x 1 um. Flow rate was set at a constant flow of 1.5 mL/min. The gradient began at 40 °C for 2 min, then ramped at 20 °C/min to 260 °C. The final temperature of 260 °C was held for 2 min. Other conditions were:

1. Injection volume of 1 uL

2. Needle washing with acetonitrile for Solvent A and B Washes

3. Split/splitless inlet temperature and FID temperature of 260 °C

4. Split injection with a split ratio of 50: 1

[0051] Titrations were performed with a Metrohm Brinkmann 776 Dosimat to determine chloride level with BCP indicator and 0.1N KOH.

[0052] Adhesion peel testing was undertaken according to a modified version of ASTM C794 on anodized aluminum substrates. The substrates were prepared by wiping twice with isopropyl alcohol (IPA) and air dried. Stainless steel screens (20 x 20 x 0.016”) (50.8 x 50.8 x 0.0406cm), 0.5” thick (1.27cm) in width were prepared by cleaning with xylene and priming with DOWSIL™ 1200 OS Primer from Dow Silicones Corporation and drying of at least 24 hours after each step. A bead of sealant was applied to the substrate and drawn down to 1/8” (0.3175cm) thickness. Next, the screen was lightly pressed into the sealant, and a second bead of sealant was applied onto the screen and drawn down to *4” (0.635cm) total thickness. Samples were cured for 7 days at room temperature and 50% relative humidity (RH). Prior to testing, a fresh score mark was created with a knife at the substrate/sealant interface just below the screen. The adhesion peel strength (pli) was measured by pulling the screen 180° at 2.0 in/min (5.08cm per minute) using an Instron 33R 4465 with a 5 kN load cell. After the peel, a user assessment of failure mode (Adhesive Failure vs Cohesive Failure) was made and recorded. After measuring initial peel strength, the same cured peel preparation was aged in water for 1 day and retested, followed by another 6d water immersion and final test.

INDUSTRIAL APPLICABILITY

[0053] To achieve high conversion to CETMS via transesterification reaction of CETES with MeOH, reaction and subsequent removal of EtOH and other materials can be repeated several times. Due to thermodynamic equilibrium limitations and higher volatility of MeOH than EtOH, during removal of EtOH, (e.g., via stripping and/or distillation) a reverse reaction can occur via reaction of the CETMS (where, in the reaction scheme above, x = 0) or the partially methoxylated species (where x = 1 or 2) with the EtOH by-product, which cannot be removed until the lower boiling point MeOH reactant is first removed.

[0054] The inventors surprisingly found that by adding water to produce Dimer in addition to the CETMS resulted in a reaction product (composition) that improved adhesion of a cured product of a polyorganosiloxane composition, as compared to adhesion of a cured product of a polyorganosiloxane composition containing CETMS with a lower amount of dimer.

DEFINITIONS AND USAGE OF TERMS

[0055] The amounts of all starting materials in a composition total 100% by weight. The Summary and the Abstract are hereby incorporated by reference. The articles ‘a’, ‘an’, and ‘the’ each refer to one or more, unless otherwise indicated by the context of specification. The singular includes the plural unless otherwise indicated. Each embodiment or alternative presented herein may be combined with any other embodiment or alternative. The term “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,” “e.g. ” “such as,” and “including” to list illustrative examples does not limit to only the listed examples. Thus, “for example” or “such as” means “for example, but not limited to” or “such as, but not limited to” and encompasses other similar or equivalent examples.

[0056] It is to be understood that the appended claims are not limited to express and particular compounds, compositions, or methods described in the detailed description, which may vary between particular embodiments which fall within the scope of the appended claims. With respect to any Markush groups relied upon herein for describing particular features or aspects of various embodiments, different, special, and/or unexpected results may be obtained from each member of the respective Markush group independent from all other Markush members. Each member of a Markush group may be relied upon individually and or in combination and provides adequate support for specific embodiments within the scope of the appended claims. [0057] Abbreviations used in this application are defined below in Table 5.

Table 5 - Abbreviations

Claims

CLAIMS:

1. A process for preparing a reaction product comprising an alkoxysilane product and a dimer, wherein the process comprises:

1) combining starting materials comprising

(A) cyanoethyltriethoxysilane,

(B) methanol, in a stoichiometric excess,

(C) water, and

(D) an acid catalyst; thereby producing a reaction mixture; and optionally 2) adding to the reaction mixture (E) an activated carbon selected from the group consisting of

(DI) bituminous coal activated carbon,

(D2) coconut activated carbon with an iodine number of at least 1200 mg/g, and

(D3) both (DI) and (D2);

3) removing materials comprising methanol, ethanol and the acid catalyst from the reaction mixture; and

4) repeating steps 1) to 3) one or more times, thereby forming the reaction product.

2. The process of claim 1, where in step 1), an amount of (A) the cyanoethyltriethoxysilane and an amount of (B) methanol is used in a molar ratio (B):(A) of at least 5:1, alternatively 5:1 to 30:1 , alternatively > 5: 1 to 30: 1, and alternatively 15:1 to 30:1.

3. The process of claim 1 or claim 2, where (D) the acid catalyst is selected from the group consisting of HC1 and an ion exchange resin.

4. The process of any one of claims 1 to 3, where (D) the acid catalyst is HC1, and the HC1 is used in an amount of at least 30 ppm based on weight of (A) the cyanoethyltriethoxysilane and weight of (B) the methanol combined, and time for step 3) is 1 to 4 hours.

5. The process of any one of claims 1 to 4, where in step 1), an amount of (C) the water is 0.05 wt% to lwt% based on weight of (B) the methanol.

6. The process of any one of claims 1 to 5, where step 2) is present.

7. The process of any one of claims 1 to 6, where the reaction product comprises: up to 80 wt% of an alkoxysilane product of formula

at least 20 wt% of a dimer of formula

each R is independently selected from the group consisting of methyl and ethyl, and each subscript x is independently 0 to 2.

8. The process of claim 7, where each R is methyl and subscript x = 0.

9. The process of claim 7 or claim 8, where the composition comprises 80 wt% to 70 wt% of the alkoxysilane product and 20 wt% to 30 wt% of the dimer.

10. Use of the reaction product prepared by the process of any one of claims 1 to 9 in a polyorganosiloxane sealant composition.

11. The use of claim 10, where the composition is an adhesion promoter, a coupling agent, or a crosslinker.

12. A method comprising: adding the reaction product of any one of claims 1 to 9 to a polyorganosiloxane sealant composition.

13. The method of claim 12, where the polyorganosiloxane sealant composition comprises an alkoxy-functional polyorganosiloxane.

14. The method of claim 12, where the polyorganosiloxane sealant composition comprises an acyloxy-functional polyorganosiloxane.