A method for inhibiting by-products in the synthesis of γ-glycidyloxypropyltrimethoxysilane

Abstract

The present invention relates to the field of fine chemical technology, and in particular to a method for inhibiting by-products in the synthesis of γ-glycidyloxypropyltrimethoxysilane. The specific technical scheme is: using chloroplatinic acid and isopropanol as raw materials, adding a co-catalyst, an inhibitor, and an epoxy ring-opening inhibitor to prepare a combined catalyst, and then using the combined catalyst, glycidyl ether, and trimethoxysilane as raw materials, heating and stirring, and performing a synthesis reaction at a certain temperature to generate γ-glycidyloxypropyltrimethoxysilane. The combined catalyst disclosed in the present invention has a small amount and a high yield. The application of the combined catalyst inhibits the generation of by-products during synthesis, and the molar yield reaches 93%, and the product content can reach more than 99%. There is almost no generation of wastewater, waste residue, and waste liquid in the whole process, which is an economical and environmentally friendly green chemical synthesis.

Description

Technical Field

[0001] The invention relates to the technical field of fine chemicals, and in particular to a method for inhibiting by-products in the synthesis of gamma-glycidyloxypropyltrimethoxysilane. Background Art

[0002] γ-Glycidyloxypropyltrimethoxysilane (trade name: KH-560) is a widely used silane coupling agent. Because it contains an oxirane ring in its molecule, it has special functions and is widely used in many fields such as plastics, coatings and adhesives to improve the mechanical strength of composite materials; improve the electrical insulation properties of integrated circuit materials and printed circuit boards in wet state; and greatly improve the adhesion in acrylic latex, polyurethane, two-component epoxy resin, etc.

[0003] Early foreign patents reported the synthesis of KH-560, but there are relatively few studies on this product in China. The preparation of silane derivatives generally uses transition metals as catalysts, among which Pt complex catalysts have higher activity. The more common Pt complex catalysts are Speier catalyst (chloroplatinic acid dissolved in isopropanol) and Karstedt catalyst (chloroplatinic acid dissolved in dimethylvinyldisiloxane). Speier catalyst has high selectivity when catalyzing the hydrosilylation reaction of olefins containing active functional groups, but its application is limited due to the long induction period; Karstedt catalyst has better activity, but due to the gelation of the catalyst, various side reactions occur in the hydrosilylation reaction.

[0004] During the synthesis reaction, a β-configuration byproduct, β-glycidyloxypropyltrimethoxysilane, is also generated. The boiling point of this byproduct is not significantly different from that of the γ-configuration product, which increases the difficulty of separating and purifying the product. Therefore, the generation of β-configuration byproducts should be suppressed as much as possible during the reaction.

[0005] At the same time, the raw material AGE also produces two isomerization products during the reaction, which are the main by-products in the reaction process and seriously affect the yield of KH-560. Therefore, the key to this process is to select suitable catalysts and co-catalysts to inhibit the production of by-products and improve the conversion rate of raw materials and the yield of KH-560.

[0006] According to US Patent US20100036146, the two isomers of AGE, cis-iso-AGE and trans-iso-AGE, accounted for 6.35% of the crude product and 81% of the product. By changing the catalyst, cis-iso-AGE still accounted for 6.4%, but trans-iso-AGE was reduced to 3%, and the crude product content could reach 87.3%. Summary of the invention

[0007] In view of the deficiencies in the prior art, the present invention provides a combined catalyst, which can effectively inhibit the generation of by-products during the synthesis of γ-glycidyloxypropyltrimethoxysilane using the combined catalyst.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0009] The invention discloses a method for preparing a combined catalyst. Chloroplatinic acid, isopropanol, a co-catalyst, a polymerization inhibitor and an epoxy ring-opening inhibitor are stirred at 20 to 80 DEG C for 30 to 60 minutes, and the combined catalyst is obtained after cooling and filtering.

[0010] Preferably, the co-catalyst is one or more of malic acid, citric acid, oxalic acid, salicylic acid, benzoic acid, terephthalic acid, p-hydroxybenzoic acid, adipic acid, acrylic acid, fumaric acid, and maleic acid; the polymerization inhibitor is one or more of hydroquinone, catechol, phenothiazine, 2,6-di-tert-butyl-p-cresol, 2,5-di-tert-butyl-hydroquinone, 2-tert-butyl-hydroquinone, p-hydroxyanisole, ZJ-701, and ZJ-705; and the epoxy ring-opening inhibitor is one or more of cobalt acetate, manganese acetate, nickel acetate, nickel nitrate, and cobalt nitrate.

[0011] Preferably, the mass ratios of chloroplatinic acid, isopropanol, co-catalyst, polymerization inhibitor and epoxy ring-opening inhibitor are 1-3, 85-95, 0.5-5, 0.5-5 and 0.5-5.

[0012] Correspondingly, a combined catalyst prepared by the above preparation method has a pH value of 4-6 and a water content of <0.05%.

[0013] Correspondingly, a method for inhibiting by-products in the synthesis of γ-glycidyloxypropyltrimethoxysilane is provided, which uses the combined catalyst prepared by the above preparation method to synthesize γ-glycidyloxypropyltrimethoxysilane.

[0014] Preferably, trimethoxysilane and the combined catalyst are subjected to a temperature-raising reaction, and then allyl glycidyl ether is slowly added dropwise. After the temperature is kept for reaction, γ-glycidyloxypropyl trimethoxysilane is obtained by distillation under reduced pressure.

[0015] Preferably, the molar ratio of trimethoxysilane to allyl glycidyl ether is 1.0-1.2:1, the dosage of the combined catalyst is 6-12 ppm, the temperature is raised to 60-90° C., the time for dripping allyl glycidyl ether is 1-3 hours, and the heat preservation reaction time is 1-2 hours.

[0016] Correspondingly, a method for synthesizing γ-glycidyloxypropyltrimethoxysilane comprises the following steps: heating trimethoxysilane and a combined catalyst for reaction, slowly dropping allyl glycidyl ether, keeping the temperature for reaction, and performing reduced pressure distillation to obtain γ-glycidyloxypropyltrimethoxysilane.

[0017] Preferably, the molar ratio of trimethoxysilane to allyl glycidyl ether is 1.0-1.2:1, the dosage of the combined catalyst is 6-12 ppm, the temperature is raised to 60-90° C., the time for dripping allyl glycidyl ether is 1-3 hours, and the heat preservation reaction time is 1-2 hours.

[0018] The present invention has the following beneficial effects:

[0019] 1. The present invention starts with improving the catalyst activity and optimizing the synthesis process, reducing the side reactions occurring during the synthesis, reducing the production cost, and improving the yield and quality of the product. The combined catalyst synthesized in the present invention has high activity and is used in small amounts. The reaction conditions for synthesizing γ-glycidyloxypropyltrimethoxysilane are mild, the amount of chloroplatinic acid used in the catalyst is small, it is easy to control, the operation is simple, the synthesis reaction time is short, the yield is high, and there are few by-products.

[0020] 2. The raw materials of the present invention are directly reacted, easy to operate, and suitable for large-scale production. The combined catalyst used in the present invention effectively improves the reaction efficiency, inhibits the generation of by-products, and improves the reaction selectivity and product yield. The product has good quality, good stability, is not easy to gel, and meets the higher standard requirements in the application of composite mid- and downstream products. Moreover, no solvent is used during the reaction, which accelerates the reaction rate and reduces energy consumption.

[0021] 3. The dosage of the combined catalyst disclosed in the present invention is 6-12 ppm, which is small in dosage and high in yield. The application of the combined catalyst inhibits the generation of by-products during synthesis, the molar yield reaches 93%, and the product content can reach more than 99%. There is almost no wastewater, waste residue, and waste liquid generated in the whole process, which is an economical and environmentally friendly green chemical synthesis. DETAILED DESCRIPTION

[0022] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0024] 1. The present invention discloses a method for preparing a combined catalyst. Chloroplatinic acid, isopropanol, a co-catalyst, an inhibitor, and an epoxy ring-opening inhibitor are stirred at 20 to 80° C. for 30 to 60 minutes, and the combined catalyst is obtained after cooling and filtering.

[0025] Wherein, the cocatalyst is one or more of malic acid, citric acid, oxalic acid, salicylic acid, benzoic acid, terephthalic acid, p-hydroxybenzoic acid, adipic acid, acrylic acid, fumaric acid, and maleic acid; the polymerization inhibitor is one or more of hydroquinone, catechol, phenothiazine, 2,6-di-tert-butyl-p-cresol, 2,5-di-tert-butyl-hydroquinone, 2-tert-butyl-hydroquinone, p-hydroxyanisole, ZJ-701, and ZJ-705; the epoxy ring-opening inhibitor is one or more of cobalt acetate, manganese acetate, nickel acetate, nickel nitrate, and cobalt nitrate. The mass ratios of chloroplatinic acid, isopropanol, cocatalyst, polymerization inhibitor, and epoxy ring-opening inhibitor are 1 to 3, 85 to 95, 0.5 to 5, 0.5 to 5, and 0.5 to 5. The pH of the combined catalyst prepared by the invention is 4-6, the water content is less than 0.05%, the content of the synthetic product reaches more than 99%, the beta addition by-product is less than 0.5%, and the product quality is high.

[0026] 2. The combined catalyst prepared by the present invention can inhibit the generation of by-products in the synthesis of γ-glycidyloxypropyltrimethoxysilane, specifically: using the combined catalyst prepared by the above preparation method to synthesize γ-glycidyloxypropyltrimethoxysilane.

[0027] Among them, the synthesis process of γ-glycidyloxypropyltrimethoxysilane is:

[0028] After heating trimethoxysilane and 6-12ppm (calculated as Pt content) of the combined catalyst to 60-90°C, slowly drip allyl glycidyl ether, the molar ratio of trimethoxysilane to allyl glycidyl ether is 1.0-1.2:1, the dripping time is 1-3h, and the temperature is kept for 1-2h. Samples are taken and analyzed by gas chromatography, and the crude product content is 84-90%. Excess trimethoxysilane is recovered, and the fraction of 116-120°C / 10mmHg is collected by vacuum distillation to obtain KH-560 (γ-glycidyloxypropyl trimethoxysilane), with a yield of 91-93% and a fine product content of more than 99%.

[0029] The present invention will be further described below in conjunction with specific embodiments.

[0030] The combined catalysts used in the following examples are all prepared by the above-mentioned method 1.

[0031] Example 1

[0032] In a 250ml four-necked flask equipped with electromagnetic stirring, reflux condenser, drying tube, constant pressure dropping funnel and thermometer, add 77g (0.6mol) of trimethoxysilane, add 12ppm (calculated by Pt content) of combined catalyst, heat to reaction temperature 90°C, slowly drop 57g (0.5mol) of allyl glycidyl ether, drop for 1h, keep warm for 1h, take samples and analyze by gas chromatography, the product content is 90%, the two isomers of AGE cis-iso-AGE and trans-iso-AGE account for 3.05% and 1.85% of the crude product respectively. Recover excess trimethoxysilane, collect the fraction of 116-120°C / 10mmHg by vacuum distillation, and obtain KH-560, the yield is 93%, and the content is greater than 99%.

[0033] Example 2

[0034] In a 250ml four-necked flask equipped with electromagnetic stirring, reflux condenser, drying tube, constant pressure dropping funnel and thermometer, add 70.6g (0.55mol) of trimethoxysilane, add 6ppm (calculated by Pt content) of combined catalyst, heat to reaction temperature 90°C, slowly drop 57g (0.5mol) of allyl glycidyl ether, drop for 1h, keep warm for 1h, take samples and analyze by gas chromatography, the product content is 85%, the two isomers of AGE cis-iso-AGE and trans-iso-AGE account for 3.35% and 2.51% of the crude product respectively. Recover the excess trimethoxysilane, collect the fraction of 116-120°C / 10mmHg by vacuum distillation, and obtain KH-560, the yield is 91%, and the content is greater than 99%.

[0035] Example 3

[0036] In a 250ml four-necked flask equipped with electromagnetic stirring, reflux condenser, drying tube, constant pressure dropping funnel and thermometer, add 70.6g (0.55mol) of trimethoxysilane, add 6ppm (calculated by Pt content) of combined catalyst, heat to reaction temperature 60°C, slowly drop 57g (0.5mol) of allyl glycidyl ether, drop for 1h, keep warm for 1h, take samples and analyze by gas chromatography, the product content is 87%, the two isomers of AGE cis-iso-AGE and trans-iso-AGE account for 3.15 and 2.47% of the crude product respectively. Recover excess trimethoxysilane, collect the fraction of 116-120°C / 10mmHg by vacuum distillation, and obtain KH-560, the yield is 92%, and the content is greater than 99%.

[0037] Example 4

[0038] In a 250ml four-necked flask equipped with electromagnetic stirring, reflux condenser, drying tube, constant pressure dropping funnel and thermometer, add 64.2g (0.5mol) of trimethoxysilane, add 6ppm (calculated by Pt content) of combined catalyst, heat to reaction temperature 90°C, slowly drop 57g (0.5mol) of allyl glycidyl ether, drop for 1h, keep warm for 1h, take samples and analyze by gas chromatography, the product content is 84%, the two isomers of AGE cis-iso-AGE and trans-iso-AGE account for 3.95% and 2.69% of the crude product respectively. Recover excess trimethoxysilane, collect the fraction of 116-120°C / 10mmHg by vacuum distillation, and obtain KH-560, the yield is 90%, and the content is greater than 99%.

[0039] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preparing a combined catalyst for inhibiting by-products in the synthesis of γ-glycidyloxypropyltrimethoxysilane, characterized in that: Chloroplatinic acid, isopropanol, a co-catalyst, an inhibitor, and an epoxy ring-opening inhibitor are stirred at 20 to 80° C. for 30 to 60 minutes, cooled, and filtered to obtain a combined catalyst; The co-catalyst is one or more of malic acid, oxalic acid, salicylic acid, benzoic acid, terephthalic acid, p-hydroxybenzoic acid, adipic acid, acrylic acid, fumaric acid, and maleic acid; the polymerization inhibitor is one or more of hydroquinone, catechol, phenothiazine, 2,6-di-tert-butyl-p-cresol, 2,5-di-tert-butyl-hydroquinone, 2-tert-butyl-hydroquinone, p-hydroxyanisole, ZJ-701, and ZJ-705; and the epoxy ring-opening inhibitor is one or more of cobalt acetate, manganese acetate, nickel acetate, nickel nitrate, and cobalt nitrate.

2. The preparation method according to claim 1, characterized in that: The mass ratio of the chloroplatinic acid, isopropanol, co-catalyst, polymerization inhibitor and epoxy ring-opening inhibitor is 1-3:85-95:0.5-5:0.5-5:0.5-5.

3. A combined catalyst prepared by the preparation method according to claim 1 or 2, characterized in that: The combined catalyst has a pH value of 4-6 and a water content of less than 0.05%.

4. A method for inhibiting by-products in the synthesis of γ-glycidyloxypropyltrimethoxysilane, characterized in that: Using the combined catalyst prepared by the preparation method according to claim 1 or 2 to synthesize γ-glycidyloxypropyltrimethoxysilane; Trimethoxysilane and a combined catalyst are subjected to a temperature-raising reaction, and then allyl glycidyl ether is slowly added dropwise. After the temperature is kept for reaction, γ-glycidyloxypropyl trimethoxysilane is obtained by vacuum distillation.

5. The method for inhibiting by-products in the synthesis of γ-glycidyloxypropyltrimethoxysilane according to claim 4, characterized in that: The molar ratio of trimethoxysilane to allyl glycidyl ether is 1.0-1.2:1, the dosage of the combined catalyst is 6-12 ppm, the temperature is raised to 60-90° C., the time for dripping allyl glycidyl ether is 1-3 hours, and the heat preservation reaction time is 1-2 hours.