Method for decolorizing cyanoethyltrimethoxysilane

Abstract

A method is disclosed for removing color from cyanoethyltrimethoxysilane from various sources. The cyanoethyltrimethoxysilane can be used in polyorganosiloxane compositions that cure to form products such as silicone sealants, which can be white or colorless.

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 / 471,512, filed June 7, 2023. U.S. Provisional Patent Application No. 63 / 471,512 is incorporated herein by reference.

[0002] A method for reducing the color of cyanoethyltrimethoxysilane is provided. More specifically, the method involves treating yellow cyanoethyltrimethoxysilane with activated carbon.

[0003] Introduction Cyanoethyltrimethoxysilane (CETMS) is useful as an adhesion promoter or coupling agent in siloxane compositions, such as room temperature vulcanizable (RTV) polyorganosiloxane sealant compositions. CETMS can be made via the hydrosilylation reaction of acrylonitrile with trichlorosilane, followed by methoxylation. CETMS can also be made by the hydrosilylation reaction of trimethoxysilane with acrylonitrile. However, these processes suffer from drawbacks, including the fact that CETMS is typically a colored liquid. For example, cyanoethyltrimethoxysilane from Gelest, Inc. (Morrisville, Pennsylvania, USA) is a pale yellow liquid. Summary of the Invention

[0004] A method for removing color from CETMS involves contacting the CETMS with wood-based activated carbon. DETAILED DESCRIPTION OF THE INVENTION

[0005] The cyanoethyltrimethoxysilane (CETMS) used in the method introduced above can be provided by any convenient means. The method for reducing the color of CETMS described above can optionally further include preparing CETMS before step 1). For example, CETMS can be prepared by a process including the hydrosilylation reaction of acrylonitrile with trichlorosilane, followed by methoxylation. Alternatively, CETMS can be prepared by a process including the hydrosilylation reaction of trimethoxysilane with acrylonitrile. Alternatively, CETMS can be prepared by a method including the transesterification reaction of cyanoethyltriethoxysilane (CETES) with methanol, and CETES can be prepared by the hydrosilylation reaction of trichlorosilane and acrylonitrile to make cyanoethyltrichlorosilane, followed by ethoxylation of cyanoethyltrichlorosilane (with ethanol). Without wishing to be bound by theory, it is believed that the impurities that impart color to CETMS may be the result of the hydrosilylation reaction described above.

[0006] More specifically, the transesterification process for making CETMS comprises: 1) combining starting materials including (A) cyanoethyltriethoxysilane (CETES), (B) a stoichiometric excess of methanol, and (C) an acid catalyst, thereby producing a transesterification reaction mixture; Optionally, 2) adding (D) activated carbon to the transesterification reaction mixture; 3) removing materials including methanol, ethanol, and (C) the acid catalyst from the transesterification reaction mixture; 4) repeating steps 1)-3) one or more times (for a total of at least two additions of methanol and (C) acid catalyst, and subsequent removal of methanol, ethanol, and catalyst).

[0007] In this process for making CETMS, the transesterification of CETES and methanol may proceed according to the transesterification scheme shown below.

[0008] [ka] In the formula for the alkoxysilane product, when x = 0, the formula is CETMS. However, partially methoxylated species, such as cyanoethyl-, diethoxy-, monomethoxysilane (when x = 2) and / or cyanoethyl-, monoethoxy-, dimethoxysilane (when x = 1), can also be formed during the processes described herein. In the dimer formula in this reaction scheme, each R is independently selected from the group consisting of methyl and ethyl. Dimers are by-products that can form during the processes described herein, and increased dimer formation can adversely affect the yield of CETMS. It is desirable to operate the reaction in a way that converts the ethoxy groups in CETES to methoxy groups to a high degree, resulting in high-purity CETMS, and minimizes dimer formation.

[0009] In step 1) of the transesterification process for making CETMS described herein, (A) CETES and (B) methanol are used in amounts sufficient to provide a stoichiometric excess of methanol. The amount of (A) CETES and (B) methanol can be at least 5:1 (B:(A) molar ratio), alternatively at least 15:1, while the (B:(A) ratio can be up to 30:1, alternatively up to 15:1. Alternatively, the (B:(A) ratio can be 5:1 to 30:1, alternatively >5:1 to 30:1, alternatively 15:1 to 30:1. Without wishing to be bound by theory, it is believed that step 1) can be carried out at room temperature or at an elevated temperature, such as up to 70°C. Alternatively, the temperature can be 21°C to 70°C. The time for the transesterification reaction in step 1) is sufficient to reach equilibrium. For example, at room temperature, the time can be 1 hour to 4 hours. However, the exact time will depend on various factors, such as the selected temperature and the choice and amount of (C) acid catalyst. Without wishing to be bound by theory, it is believed that conducting the transesterification reaction in step 1) at room temperature can be efficient in terms of the time, energy, and costs associated with heating and cooling. The use of an acid catalyst can offer the advantage of allowing for a rapid reaction at room temperature, which minimizes time and operating costs. The reaction can optionally be carried out at an elevated temperature. Furthermore, step 1) can be carried out under conditions that minimize or eliminate the presence of moisture. Without wishing to be bound by theory, it is believed that moisture contamination can initiate the side reaction of dimer formation, which reduces the CETMS yield when maximizing the CETMS yield is desired.

[0010] The starting material (C), the acid catalyst, can be selected from the group consisting of, for example, a hydrogen halide of formula HX (wherein X is Cl, Br, or I), a sulfonic acid (such as toluenesulfonic acid or trifluoromethanesulfonic acid), and an ion exchange resin. Alternatively, the (C) acid catalyst can be a hydrogen halide, or alternatively, the acid catalyst can be HCl. When the (C) acid catalyst is a hydrogen halide, for example, HCl, the hydrogen halide (e.g., HCl) can be used in an amount of at least 1 ppm, alternatively at least 5 ppm, alternatively at least 10 ppm, or alternatively at least 30 ppm, based on the combined weight of (A) CETES and (B) MeOH, while simultaneously, the amount of hydrogen halide (e.g., HCl) can be up to 100 ppm, alternatively at most 50 ppm, or alternatively at most 30 ppm. Alternatively, the amount of hydrogen halide (e.g., HCl) can be 10 ppm to 100 ppm, alternatively 10 ppm to 50 ppm, alternatively 30 ppm, on the same basis. Alternatively, if ion exchange resin is used, its amount can be at least 0.1%, alternatively at least 0.5%, of solids relative to the liquid, while at the same time, its amount can be up to 30%, on the same basis. Alternatively, the amount of ion exchange resin can be 0.1% to 30%.

[0011] The starting materials used in step 1) of this process are known in the art and commercially available. CETES is available as a pale yellow liquid from Gelest Inc. (Morrisville, Pennsylvania, USA), and CETES is available as a yellow liquid from TCI America. MeOH and HCl are available from various sources, including Sigma-Aldrich, Inc. (St. Louis, Missouri, USA). Ion exchange resins, for use herein, can be strong acid and weak acid cation exchange resins, where the ionic form of the resin is not hydrogen (H+). Such ion exchange resins are commercially available, for example, DOWEX™ Monosphere 2030, DOWEX™ MARATHON™ 1200 (Na+ form), and AMBERLITE IR122 Na from TDCC.

[0012] Combining the starting materials in step 1) of the transesterification process can be carried out batchwise or continuously by any convenient means, such as mixing. Mixing can be carried out in conventional equipment, such as a batch reactor equipped with an agitator and, optionally, a heating means, such as a jacket. Alternatively, the process can be carried out in a packed bed reactor, for example, the reactor can be packed with (C) an acid catalyst, e.g., an ion exchange resin, when a solid catalyst is used, and / or activated carbon, when step 2) is present.

[0013] Step 2) of the process involves combining (D) activated carbon and the transesterification reaction mixture prepared in step 1). Step 2) is optional. However, if used, step 2) can be carried out at room temperature, for example, by mixing activated carbon with the transesterification reaction mixture prepared in step 1) for a time sufficient to adsorb the acid HCl from the transesterification reaction mixture. The exact time depends on various factors, such as the size of the vessel used in step 2) (which can be the same as the reactor used in step 1), but the time can be at least 1 hour, alternatively at least 2 hours, alternatively at least 4 hours, alternatively at least 8 hours, or alternatively at least 16 hours, while the time can be up to 48 hours, alternatively up to 24 hours, or alternatively up to 16 hours. Step 2) can be carried out under conditions that minimize or exclude moisture to prevent dimer formation and maximize the yield of CETMS.

[0014] When step 2) is present, (D) activated carbon may be selected from the group consisting of (D1) bituminous activated carbon, (D2) coconut activated carbon having an iodine value of ≧1200 mg / g, and (D3) a combination of both (D1) and (D2). (D1) bituminous activated carbon and (D2) coconut activated carbon are known in the art and are commercially available from various sources, such as General Carbon Corporation (Paterson, New Jersey, USA) or Calgon Carbon (Pittsburgh, Pennsylvania, USA). The bituminous activated carbon may have an iodine value 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 activated carbon may have an iodine value of up to 1200 mg / g(min), alternatively up to 1100 mg / g(min), alternatively up to 1,000 mg / g(min), alternatively up to 950 mg / g(min). Alternatively, the iodine value of the bituminous activated carbon may be between 600 mg / g(min) and 1200 mg / g(min), alternatively between 750 mg / g(min) and 1200 mg / g(min), alternatively between 900 mg / g(min) and 1200 mg / g(min), alternatively between 900 mg / g(min) and 1050 mg / g(min). The iodine value of the coconut activated carbon may be ≧1200 mg / g(min), alternatively between 1200 mg / g(min) and 1500 mg / g(min), alternatively between 1200 mg / g(min) and 1300 mg / g(min).

[0015] Examples of bituminous activated carbon include GC 12x40, a virgin activated carbon in granular form having an iodine number of 900 mg / g(min) and a density of 0.47-0.53 g / cc, available from General Carbon Corporation, and CAL™ 12x40 granular activated carbon, a re-agglomerated metallurgical grade bituminous coal having an iodine number of 1000 mg / g(min), available from Calgon Carbon. Other bituminous activated carbons from Calgon Carbon include CPG™ LF 12x40, which has an iodine value of 950 mg / g(min), FILTRASORB™ 300M, which has an iodine value of 900 mg / g(min), FILTRASORB™ 400M, which has an iodine value of 1000 mg / g(min), HPC MAXX, which has an iodine value of 900 mg / g, and SGL 8x20, a granular activated carbon made from bituminous coal combined with a binder and has an iodine value of 900 mg / g(min). Coconut activated carbons include OLC Plus 12x30, which has an iodine value of 1200 mg / g(min) and a density of 0.45 g / cc, and is also available from Calgon Carbon.

[0016] If step 2) is present (i.e., activated carbon is used), the process may further include treating the activated carbon before use in step 2). Treatment may be carried out, for example, to dry the activated carbon (e.g., to remove all or a portion of any adsorbed moisture to minimize the possibility of 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 under ambient or reduced pressure. The activated carbon may be heated and stored under an inert atmosphere, such as nitrogen, before use in step 2).

[0017] Step 3) of the process involves removing materials from the transesterification reaction mixture, including (excess) unreacted (B) methanol, ethanol (produced as a by-product), and (C) acid catalyst. Step 3) can be carried out by any convenient means. Step 3) can include, for example, filtration to remove solid materials, such as ion exchange resins if used as the (C) acid catalyst, and / or activated carbon if present in step 2). Step 3) can also include stripping and / or distillation under heat and optionally reduced pressure, which can remove methanol, ethanol, and liquid acid catalysts, such as HCl.

[0018] Step 4) of the transesterification process to produce CETES involves repeating steps 1)-3) one or more times. Step 4) can involve repeating 1)-3) at least once, alternatively 1-4 times. Without wishing to be bound by theory, it is believed that repeating steps 1)-3) too many times (e.g., 5 or more times (alternatively 5 or more times) for a total of 6-7 or more additions and subsequent removals of methanol and acid catalyst can result in the formation of undesirably large amounts of dimer and / or increased costs that make the process impractical on a commercial scale. Alternatively, step 4) can involve repeating steps 1)-3) once or twice, especially when step 2) is present. Without wishing to be bound by theory, it is believed that due to thermodynamic equilibrium limitations and the higher volatility of methanol relative to ethanol, a back reaction may occur during step 3) (e.g., via stripping and / or distillation) via reaction of CETMS (when x=0 in the alkoxylation product formula shown above) or partially methoxylated species (when x=1 or 2) with the EtOH by-product (which cannot be removed until all or most of the lower boiling MeOH has first been removed). Furthermore, the inventors have surprisingly found that treating the transesterification reaction mixture with activated carbon in step 2) minimizes this back reaction. Because each repetition of steps 1)-3) can add cost to the process, it is desirable to minimize the number of repetitions in step 4) for efficiency, provided that the yield and purity of the CETMS product are achieved.

[0019] The transesterification process described above can be carried out by the reaction of the formula:

[0020] [ka] The conversion of the ethoxy groups of the CETES starting material to methoxy groups, as measured by the test methods described below and used in the examples, can be at least 90 GC area %, alternatively at least 91 GC area %, alternatively at least 92 GC area %, alternatively at least 93 GC area %, alternatively at least 94 GC area %, while the conversion can be up to 100 GC area %, alternatively at most 99 GC area %, alternatively at most 98 GC area %, alternatively at most 97 GC area %, alternatively at most 96 GC area %. The purity of CETMS, as measured by the test methods described below and used in the examples, can be at least 72 GC area%, alternatively at least 81 GC area%, alternatively at least 86 GC area%, alternatively at least 89 GC area%, alternatively at least 90 GC area%, while at the same time, the purity of CETMS can be up to 100 GC area%, alternatively up to 98 GC area%, alternatively up to 95 GC area%, alternatively up to 92 GC area%, alternatively up to 90 GC area%. The amount of dimer can be 0, alternatively 1 wt% to 10 wt%, alternatively 1.5 wt% to 9 wt%, alternatively 1.8 wt% to 6 wt%, alternatively 2 wt% to 3 wt%. However, the amount of dimer can vary depending on whether step 2) is present. For example, the amount of dimer can be 1 wt% to 3 wt%, alternatively 1.5 wt% to 2 wt%, alternatively 1.8 wt% if step 2) of the process is omitted (no treatment agent is used). If a treating agent (eg, activated carbon) is used, the amount of dimer may be 5% to 10% by weight, alternatively 6% to 9% by weight.

[0021] Alternatively, the transesterification process described above can be modified to produce CETMS further comprising a dimer. In the transesterification process described above, water can optionally be added in step 1), for example, by combining water with methanol prior to step 1). The water generally is not limited and can be pure (i.e., free or substantially free of minerals and / or other impurities). Alternatively, the water can be treated or untreated prior to its addition in step 1), described above. Examples of processes that can be used to purify water include distillation, filtration, deionization, and combinations of two or more thereof, whereby the water can be deionized, distilled, and / or filtered. Alternatively, the water can be untreated (e.g., tap water, i.e., well water provided by a municipal water system or used without further purification). Water can be utilized in an amount selected by one skilled in the art depending on various factors, such as the desired amount of dimer formed in the reaction product, the reaction parameters employed, the scale of the reaction, and the species of acid catalyst selected. However, the amount of water can be 0.05% to 1% based on the weight of (B) methanol.

[0022] This process is formula

[0023] [ka] and an alkoxysilane product of formula

[0024] [ka] wherein R and x are as described above. Alternatively, each R can be methyl. Alternatively, each x can be 0. Alternatively, the composition comprises: formula

[0025] [ka] and cyanoethyltrimethoxysilane (CETMS) having the formula

[0026] [ka] and its dimer having the formula: Alternatively, the composition may consist essentially of CETMS and its dimer. Alternatively, the composition may consist of CETMS and its dimer. Alternatively, the composition may be substantially free of, or free of, methoxy groups in the alkoxysilane product and dimer. In the processes described above, the conversion of the ethoxy groups of the CETES starting material to methoxy groups, as measured by the test methods described below and used in the examples, 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%, alternatively at least 94 GC area%, while at the same time, the conversion may be up to 100 GC area%, alternatively at most 99 GC area%, alternatively at most 98 GC area%, alternatively at most 97 GC area%, alternatively at most 96 GC area%. The purity of the CETMS, as measured by the test methods described below and used in the examples, can be at least 72 GC area%, alternatively at least 81 GC area%, alternatively at least 86 GC area%, alternatively at least 89 GC area%, alternatively at least 90 GC area%, while at the same time, the purity of the CETMS can be up to 100 GC area%, alternatively up to 98 GC area%, alternatively up to 95 GC area%, alternatively up to 92 GC area%, alternatively up to 90 GC area%. The amount of dimer can be at least 20 wt% (based on the combined weight of alkoxysilane product and dimer), and on the same basis, alternatively 20 wt% to 30 wt%, alternatively 20 wt% to 29 wt%, alternatively 20 wt% to 28 wt%, alternatively 20 wt% to 27 wt%, alternatively 20 to 26 wt%. Without wishing to be bound by theory, it is believed that when a product containing 20% to 30% by weight of dimer is used in a polyorganosiloxane composition, the tack of the cured product of the composition may be improved compared to the cured product of a composition containing CETMS with a lower amount of dimer.

[0027] Products prepared by any of the processes described above typically have a color that is pale yellow to yellow, i.e., a b of ≥ 38, alternatively 38-60, according to the color measurements in the Examples below. * Contains CETMS with values.

[0028] The adhesion promoters and coupling agents are colorless or have a low color value (i.e., a b of <38 as measured by the color measurements described in the Examples below) so that they do not adversely affect the color of the desired product. * value, alternatively b from 0 to 10 * There is an industrial need for these additives with high color values. For certain (e.g., colorless or white polyorganosiloxane compositions), it is undesirable to include colored (e.g., pale yellow or yellow) components that can adversely affect the appearance of the final cured polyorganosiloxane product, such as a sealant. The method of the present invention provides a method for reducing the b * Used to reduce the value to <38, alternatively <10, alternatively to a value between 0 and 10.

[0029] Methods for reducing the color of CETMS A method for reducing the color of cyanoethyltrimethoxysilane (CETMS) is 1) ≧38 color b * CETMS and wood-based activated carbon with a b value of CETMS * for a time sufficient to reduce the .DELTA.H of the solution to <38; 2) Separating the wood-based activated carbon from the cyanoethyltrimethoxysilane.

[0030] The method for removing color from CETMS introduced above is based on a b of ≥ 38. *The method includes step 1), which comprises contacting a CETMS (which may be prepared by any of the processes described above) and a wood-based activated carbon having a value of 0.01g. The contacting of the CETMS and the activated carbon of the wood-based activated carbon may be carried out by any convenient means. For example, a continuous mode may involve pumping the CETMS through a vessel such as a drum or bed containing a packed bed of wood-based activated carbon. The size of the bed may be such that after one pass, the b * Alternatively, multiple passes may be sufficient to reduce the b * Alternatively, in a batch mode, wood-based activated carbon can be added to CETMS, for example, in the vessel used to prepare CETMS, and the wood-based activated carbon can then be removed, for example, by filtration. This is because the CETMS can be prepared in a batch mode as described above. * The amount of wood-based activated carbon can be calculated by the b value of the CETMS to be treated. * The amount of CETMS and the amount of activated carbon present in the activated carbon may vary depending on various factors, including the amount of CETMS present and whether continuous or batch mode is used. For example, step 1) may involve mixing 93% to 99% by weight of CETMS and 1% to 7% by weight of wood-based activated carbon in batch mode.

[0031] The wood-based activated carbon used to remove color from CETMS is different from the bituminous or coconut activated carbon used in the transesterification process for making CETMS described above. Wood-based activated carbon, which may be referred to as plant-based activated carbon depending on the brand selected, is useful in the present invention. The wood-based activated carbon may have phosphoric acid within its pore structure. Optionally, the wood-based activated carbon is activated with phosphoric acid prior to step 1). Wood-based activated carbons produced by phosphoric acid activation are commercially available from various sources, such as ACTICARBONE™ BGE and ACTICARBONE™ BGX products from Calgon Carbon Corporation, and NORIT™ CNSP and NORIT™ C Gran from Norit Activated Carbon (Marshall, Texas, USA). Phosphoric acid activation is typically performed at 1500-2500 m 2 Carbons with very wide surface areas, in the range of 0.22 g / cm, can be produced and are commercially available in granular, pelleted, or powder form from a variety of sources, including Calgon Carbon Corporation or Carbon Activated Corp. (Compton, California, USA). Wood-based activated carbons can have an iodine value of >600 (alternatively >600-1500) or a molasses value of >150. Wood-based activated carbons have an iodine value of 0.22 g / cm. 3 ~0.24g / cm 3 The apparent density may be

[0032] The method for removing color from CETMS may optionally further include one or more additional steps. For example, the method may optionally further include drying the wood-based activated carbon before contacting it with CETMS in step 1).

[0033] Step 2) of the method described above can be carried out by any convenient means. For example, step 2) can include filtering the CETMS after step 1), thereby removing the wood-based activated carbon.

[0034] How to use Color value b<38, alternatively 0-10, generated as described above * CETMS having the formula (I) can be used in polyorganosiloxane compositions, such as room-temperature vulcanizable organopolysiloxane compositions. RTV organopolysiloxane compositions are known in the art, such as those disclosed in U.S. Patent No. 4,483,973 to Lucas et al., U.S. Patent No. 5,962,559 to Lucas et al., U.S. Patent No. 7,550,548 to Hatanaka et al., U.S. Patent No. 7,674,871 to Koch et al., U.S. Patent Application Publication No. 2007 / 0173597 to Williams et al., and PCT Patent Application Publication No. WO 2007 / 024792. CETMS can function as an adhesion promoter, coupling agent, and / or crosslinker in the polyorganosiloxane composition. Alternatively, the reaction product can be added to a commercially available RTV sealant, such as XIAMETER™ SLT-5200 from TDCC. Without wishing to be bound by theory, it is believed that the polyorganosiloxane compositions containing CETMS prepared as described herein have a low b * Due to the color value, it is believed that it may be useful in white or colorless sealants. [Example]

[0035] The following invention is provided to illustrate the invention to one of ordinary skill in the art and should not be construed as limiting the scope of the invention as claimed. Adsorbents were obtained and prepared as follows: The adsorbents received from the supplier had various concentrations of moisture.

[0036] [Table 1]

[0037] All adsorbents were dried consistently in a vacuum oven at 130°C for 16 hours. Once dry, the adsorbents were removed from the hot oven and placed in a bottle. The bottle was then stored in a dry box.

[0038] In this Example 1, adsorbents were screened in a shaker test as follows: Using adsorbents that had been dried and stored in a dry box, the adsorbents were weighed based on the desired solid-to-liquid ratio and added to glass vials in a hood. CETMS was then added to the vials. Once addition was complete, the vials were then placed on a wrist shaker and shaken for 24 hours.

[0039] After 24 hours of shaking, the vials were placed back inside the hood. The treated CETMS was analyzed to determine the effectiveness of the adsorbent as follows: A 5 mL syringe threaded onto a 0.45 micron filter was used to stain the contents of each vial. The effluent from the filter was a clear liquid free of adsorbent particulates. The clear liquid was sent for color testing.

[0040] Color measurements were performed using a Konica Minolta CM-5 spectrophotometer equipped with a C illuminant and a 2° observer. * , a * , and b * The primary measurements used are blue and yellow. * and higher b * is more yellow. * and a * The value is also recorded, L * is a measure of brightness, with 100 being the brightest and a * measures green and red, positive numbers are red and negative numbers are green.

[0041] Table 1 shows the color results for different activated carbons with the same solid to liquid ratio, i.e., 3% solids, 97% liquid. As can be seen from Table 2, Acticarbone™ BGX, an acidic wood-based activated carbon, showed the lowest b value (least yellow color).

[0042] [Table 2]

[0043] In this Example 2, shaker tests were performed as described in Example 1, but the amounts of activated carbon and CETMS were varied. The activated carbon, amounts, and color test results are shown below in Table 3. The data in Table 3 show that 7% ACTICARBONE BGX provided better color reduction than 10% and 12% CAL 12X40 under otherwise identical processing conditions.

[0044] [Table 3]

[0045] In this Example 3, shaker tests were conducted as described in Example 1, but using different wood-based and bituminous activated carbons, CAL 12x40, each at a 3% loading. The activated carbons tested and the results are in Table 4. The data in Table 4 show that all of the wood-based activated carbons tested provided better color reduction than the bituminous activated carbon under otherwise identical conditions.

[0046] [Table 4]

[0047] In this Example 4, shaker tests were conducted as described in Example 1, but with different amounts of activated carbon, as shown below in Table 5. The data in Table 5 show that ACTICARBONE BGX provided better color reduction than CAL 12X40 at each loading tested.

[0048] [Table 5]

[0049] In this Example 5, a single-pass continuous process for removing color from CETMS was modeled as follows: A column having a length of 18 inches (45.72 cm) and a diameter of 3 inches (7.62 cm) (length / diameter, L / D ratio = 6) was packed with activated carbon. *CETMS, having a color value of 0.05% = 38, was pumped into the column inlet at 50 g / min. Samples were collected at the column outlet and analyzed for color. The operating conditions are shown in Table 6 below.

[0050] [Table 6]

[0051] Even though the column containing CAL 12X40 contained more than twice the mass of activated carbon as the column containing ACTICARBONE™ BGX (due to density differences), the column packed with ACTICARBONE™ BGX provided better color reduction than the column packed with CAL 12X40. Samples were taken from the column effluent at various times and color was measured as described above. The results are in Table 7 below.

[0052] [Table 7]

[0053] [Table 8]

[0054] The data in Table 7 show that ACTICARBONE™ BGX used in Run 5-1 provided better color reduction than CAL 12X40 used in Run 5-2, even though a larger mass of CAL 12X40 activated carbon was used compared to that used in Run 5-1. These data show that not only does ACTICARBONE™ BGX provide better color reduction than CAL 12X40, but the process can be run longer before the activated carbon needs to be replaced or regenerated when ACTICARBONE™ BGX is used.

[0055] Test Method Gas chromatography (GC) was used to verify the composition of the materials. All reported compositions in the above examples were based on GC area %. An Agilent 7890A GC system equipped with helium carrier gas and an FID detector was used with a Restek Rtx-1 30 m x 0.25 mm x 1 um. The flow rate was set at a constant flow rate of 1.5 mL / min. The gradient started at 40°C for 2 minutes and then increased to 260°C at 20°C / min. The final temperature of 260°C was held for 2 minutes.

[0056] Other conditions used were as follows: 1.1uL injection volume 2. Needle Wash 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

[0057] Titrations were performed using a Metrohm Brinkmann 776 Dosimat to determine chloride levels using BCP indicator and 0.1 N KOH. [Industrial Applicability]

[0058] CETMS is useful as an adhesion promoter or coupling agent in polyorganosiloxane compositions, such as room-temperature vulcanizable polyorganosiloxane sealant compositions. However, CETMS is not widely available commercially, and those that are available typically suffer from the drawback of being pale yellow or yellow in color. There is an industrial need for polyorganosiloxane compositions containing CETMS that cure to form colorless or white cured products. Thus, polyorganosiloxane compositions that have a light or no color, i.e., a b of 0 to 10, according to the color measurement described in the Examples above, are generally used. * It is desirable to provide CETMS that have value.

[0059] Definitions and Usage of Terms The amounts of all starting materials in the composition total 100% by weight. All amounts, ratios, and percentages are by weight unless the context of the specification dictates otherwise. 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 the context of the specification dictates otherwise. The singular includes the plural unless the context of the specification dictates otherwise. Each embodiment or alternative presented herein may be combined with any other embodiment or alternative. The term "comprising" and its derivatives, such as "comprise" and "comprises," are used herein in their broadest sense to mean and encompass the terms "including," "include," "consist(ing) essentially of," and "consist(ing of). The use of "for example," "eg," "such as," and "including" to list examples does not limit 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.

[0060] It is understood that the appended claims are not limited to the explicit and specific compounds, compositions, or methods described in the detailed description, which may vary among specific embodiments falling within the scope of the appended claims. With respect to any Markush group relied upon herein to describe particular features or aspects of various embodiments, different, special, and / or unexpected results may be obtained from each element of the respective Markush group independent of all other Markush elements. Each element of a Markush group may be relied upon individually and / or in combination to provide sufficient support for specific embodiments within the scope of the appended claims.

[0061] Abbreviations used in this application are defined in Table 8 below.

[0062] [Table 9]

[0063] Embodiments of the present invention In a first embodiment, a method for producing CETMS comprises: I) A transesterification process comprising: 1) (A) cyanoethyltriethoxysilane (CETES), (B) a stoichiometric excess of methanol, and (C) combining the starting materials with an acid catalyst, thereby producing a transesterification reaction mixture; Optionally, 2) adding (D) activated carbon to the transesterification reaction mixture; 3) removing materials including methanol, ethanol, and (C) the acid catalyst from the transesterification reaction mixture; 4) Repeat steps 1)-3) one or more times (for a total of at least two additions of methanol and (C) acid catalyst, and subsequent removal of methanol, ethanol, and catalyst), thereby obtaining a color value b of ≥ 38. *and producing a transesterification reaction product comprising CETMS having a value of 0.015. II) Cyanoethyltrimethoxysilane b * A color value b > 30 for a time sufficient to reduce * contacting a CETMS having the formula (I) with wood-based activated carbon; III) separating the wood-based activated carbon from the cyanoethyltrimethoxysilane.

[0064] In a second embodiment, in the method of the first embodiment, step I) further comprises adding water in an amount of 0.05% to 1% by weight based on the weight of (B) methanol.

[0065] In a third embodiment, in step II) of the method of the second embodiment, the wood-based activated carbon is activated with phosphoric acid prior to step 1).

[0066] In a fourth embodiment, in step II) of the method of any of the preceding embodiments, the wood-based activated carbon has an iodine value >600.

[0067] In a fifth embodiment, in step II) of the method of any one of the preceding embodiments, the activated wood carbon has a concentration of 0.22 to 0.24 g / cm 3 It has a density of

[0068] In a sixth embodiment, in step II) of the method according to any one of the preceding embodiments, the wood-based activated carbon comprises ACTICARBONE™ BGX, ACTICARBONE™ BGE, NORIT™ CNSP, NORIT™ C Gran, or a combination thereof.

[0069] In a seventh embodiment, the method of any one of the preceding embodiments, wherein step 2) in the transesterification process is present.

[0070] In an eighth embodiment, in the method of the seventh embodiment, the activated carbon added in step 2) is selected from bituminous activated carbon and coconut activated carbon.

Claims

1. 1. A method for reducing the color of cyanoethyltrimethoxysilane, comprising: 1) Color b ≧ 38 ＊ Cyanoethyltrimethoxysilane having a value of b and wood-based activated carbon are mixed together. ＊ for a time sufficient to reduce the .DELTA. to <38; 2) separating the wood-based activated carbon from the cyanoethyltrimethoxysilane.

2. 10. The method of claim 1, wherein the wood-based activated carbon is activated with phosphoric acid prior to step 1).

3. 3. The method of claim 1 or 2, wherein the wood-based activated carbon has an iodine value of >600.

4. The wood-based activated carbon has a density of 0.22 to 0.24 g / cm ３ The method according to any one of claims 1 to 3, wherein the granules have a density of

5. 5. The method of any one of claims 1 to 4, wherein the wood-based activated carbon comprises ACTICARBONE™ BGX, ACTICARBONE™ BGE, NORIT™ CNSP, NORIT™ C Gran, or a combination thereof.

6. 6. The method of claim 1, wherein step 1) comprises mixing 93% to 99% by weight of cyanoethyltrimethoxysilane and 1% to 7% by weight of the wood-based activated carbon in a batch mode.

7. 6. The method of any one of claims 1 to 5, wherein step 1) comprises flowing the cyanoethyltrimethoxysilane through a packed bed of the wood-based activated carbon in a continuous process.

8. 8. The method of claim 1, wherein step 2) comprises filtering the cyanoethyltrimethoxysilane after step 1), thereby removing the wood-based activated carbon.

9. 9. The method of any one of claims 1 to 8, wherein the method further comprises, prior to step 1), preparing the cyanoethyltrimethoxysilane by a process comprising a hydrosilylation reaction of acrylonitrile with trichlorosilane, followed by methoxylation.

10. 9. The method of claim 1, further comprising, prior to step 1), preparing the cyanoethyltrimethoxysilane by a process comprising a hydrosilylation reaction of trimethoxysilane with acrylonitrile.

11. 9. The method of claim 1, further comprising, prior to step 1), preparing the cyanoethyltrimethoxysilane by a process comprising transesterification of cyanoethyltriethoxysilane with methanol.

12. 12. The method of claim 11, wherein the process further comprises adding water, thereby producing a dimer.

13. The transesterification reaction comprises: i) (A) cyanoethyltriethoxysilane, (B) a stoichiometric excess of methanol; optionally water, and (C) combining starting materials, including an acid catalyst, thereby forming a reaction mixture; Optionally, ii) adding to the reaction mixture: (D1) bituminous activated carbon; (D2) coconut activated carbon having an iodine value of at least 1200 mg / g; and (D3) Both (D1) and (D2) (D) adding activated carbon selected from the group consisting of: iii) removing materials from the reaction mixture, including methanol, ethanol, and the acid catalyst; and iv) repeating steps i) through iii) one or more times, thereby forming the reaction product comprising the cyanoethyltrimethoxysilane.

14. 14. The method of claim 12 or 13, wherein (C) the acid catalyst is selected from the group consisting of HCl and an ion exchange resin.

15. The method according to claim 13 or 14, wherein in step i), the amount of water is 0.05% by weight to 1% by weight based on the weight of (B) the methanol.

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