CN109824715B - Method for synthesizing tris (3-trimethoxysilylpropyl) isocyanurate by addition method - Google Patents

Abstract

The invention relates to a method for synthesizing tris (3-trimethoxysilylpropyl) isocyanurate by an addition method; belongs to the field of organosilicon fine chemical synthesis. The invention effectively improves the reaction activity of the hydrosilylation of the isocyanurate nitrogen-containing olefin and reduces the production cost by neutralizing the raw material trimethoxyhydrosilane and using the self-made platinum catalyst, and has the characteristics of good appearance, high content, low free chlorine and no harmful isocyanate monomer residue.

Description

Method for synthesizing tris (3-trimethoxysilylpropyl) isocyanurate by addition method

Technical Field

The invention relates to a method for synthesizing tris (3-trimethoxysilylpropyl) isocyanurate by an addition method; belongs to the field of organosilicon fine chemical synthesis.

Background

The tris (3-trimethoxysilylpropyl) isocyanurate has good high-temperature resistance and flame retardance due to the fact that the isocyanurate six-membered ring structure similar to a benzene ring is contained. The adhesive is often used as an adhesion promoter, can improve the adhesion of surfaces which are difficult to adhere, such as plastics, can still keep thermal stability at the temperature of 200 ℃, can be mixed with most hot melt resins for use, and is suitable for various substrates. The synthesis method of tris (3-trimethoxysilylpropyl) isocyanurate is various, and can be divided into a condensation method, a trimerization method, a cracking method, an addition method and the like according to the reaction mode.

The condensation method is that chloropropyl alkoxy silane is used as a basic raw material and directly reacts with sodium cyanate or sodium cyanurate to remove generated sodium chloride salt, so as to obtain the isocyanurate product. Because sodium cyanate and sodium cyanurate have low nucleophilicity and are not easy to produce substitution reaction with chloropropylalkoxysilane, the reaction must be carried out under the synergistic action of high temperature, phase transfer catalyst and solvent. The data show that the reaction temperature of the chloralkane and the sodium cyanate is usually as high as 120-160 ℃, and at the temperature, the stability of the common solvent such as DMF and the common phase transfer catalyst such as tetrabutylammonium bromide are obviously reduced, and decomposition is easy to occur, thereby causing the adverse effects of reduction of the reaction conversion rate, deepening the color and luster of the product and the like.

The trimerization method is obtained by taking 3-isocyanate propyl trimethoxy silane as a raw material and carrying out trimerization reaction under the action of a basic catalyst. Chinese patent CN101805366 "preparation method of tris (3-trimethoxysilylpropyl) isocyanurate" mentions that sodium acetate, sodium methoxide and the like are used as trimerization reaction catalysts, N, N-dimethylformamide and N, N-diethylformamide are used as solvents, tris (3-trimethoxysilylpropyl) isocyanurate is synthesized at the reaction temperature of 80-250 ℃, and separation and purification are carried out by adopting molecular distillation. Compared with a condensation method, the trimerization method has obvious advantages on appearance and quality of a synthesized product, but the production cost of the product is high due to the high price of the raw material 3-isocyanatopropyl trimethoxy silane.

The cracking method is that 3- (methoxycarbonylamino) propyl trimethoxy hydrosilane is used as raw material, and is cracked at high temperature under the action of catalyst, firstly methanol is decomposed to form monoisocyanate silane, and then monoisocyanate silane undergoes self-polymerization reaction to generate isocyanurate silane. A similar reaction is mentioned in U.S. Pat. No. 2006013093, which uses ammonium carboxylates, alkali metal carboxylates or alkaline earth metal carboxylates as cracking catalysts to cleave silylcarbamates to isocyanates, which then continue to polymerize under the catalysis of the carboxylates to form silylisocyanurates. The cracking method has relatively low production cost, but the reaction temperature is higher than that of the condensation method, and the reaction catalyst is also usually selected from alkaline earth metal salt substances, so that the polymerization degree is easily increased, polymers are increased, the viscosity of the product is increased, the product is yellowed, and the application performance of the product is seriously influenced.

The addition method is characterized in that triallyl isocyanurate and trimethoxy hydrosilane are used as raw materials, and the tris (3-trimethoxysilylpropyl) isocyanurate is directly synthesized through addition reaction. However, this method also has problems of poor addition activity, low yield, high boiling point of the product, and inability to purify efficiently by distillation.

Disclosure of Invention

The invention aims to: provides a method for synthesizing tris (3-trimethoxysilylpropyl) isocyanurate by an addition method, which has the advantages of low production cost, good product appearance, high content, low free chlorine and no harmful isocyanate monomer residue.

The technical scheme of the invention is as follows:

a method for synthesizing tris (3-trimethoxysilylpropyl) isocyanurate by an addition method is characterized by comprising the following steps:

1) and mixing chloroplatinic acid hexahydrate, isopropanol and ethylene diamine tetraacetic acid ferric sodium salt according to the mass ratio of 1: 30: 2-4, heating to 40-50 ℃, reacting for 4-5 hours, and filtering to remove a small amount of generated sodium chloride salt to obtain a platinum catalyst; standby;

2) adding 0.5 to 1 mass percent of cyclohexene oxide into the acidic trimethoxy hydrosilane, and standing for 4 to 6 hours at normal temperature until the free chlorine of the trimethoxy hydrosilane is reduced to less than 15 ppm;

3) adding triallyl isocyanurate into a reactor, adding a spare platinum catalyst, heating to 100 ℃, then beginning to dropwise add neutralized trimethoxy hydrosilane to perform addition reaction, controlling the reaction temperature in the addition reaction at 110 ℃ with 100-; obtaining a crude product of the tris (3-trimethoxysilylpropyl) isocyanurate;

4) introducing the crude product into a distillation device, distilling to remove unreacted trimethoxy silane, wherein the distillation temperature is 85-95 ℃, the vacuum degree requirement is more than 0.098MPa, cooling after distilling for 6h, and filtering by a positive pressure filter under the protection of nitrogen to obtain the product; finished products of tris (3-trimethoxysilylpropyl) isocyanurate.

The total chlorine of the acidic trimethoxy silane is 200-400 ppm.

The dosage of the platinum catalyst accounts for 0.3-0.5% of the mass of the fed triallyl isocyanurate.

The molar ratio of the trimethoxyhydrosilane to the triallyl isocyanurate as the raw materials is 3.06-3.12: 1.0.

the invention has the advantages that:

compared with the traditional monoisocyanate trimerization method and the sodium cyanate chloroalkane condensation method, the method for synthesizing the tris (3-methoxylsilyl propyl) isocyanurate by the addition method has the following advantages:

1. the production cost is low. High-quality tris (3-methoxylsilyl) isocyanurate is mostly prepared by adopting a monoisocyanate trimerization method, 3-isocyanatopropyl trimethoxy silane is used as a main raw material, and the 3-isocyanatopropyl trimethoxy silane is complex in preparation process and high in price, so that the cost is high. The invention successfully overcomes the problem of low hydrosilylation reaction activity of an amine-containing system through continuous tests, and the tris (3-methoxysilylpropyl) isocyanurate is synthesized with high yield by taking trimethoxyhydrosilane and triallyl isocyanurate as raw materials, thereby greatly reducing the production cost.

2. The product has high purity. The monoisocyanate trimerization method is based on the condensation method of chloralkane with sodium cyanate, then isocyanate tripolymer is obtained through high-temperature catalytic polymerization, side reaction is inevitably generated in the polymerization process, and isocyanate dimer and polymer are generated, and a small amount of unreacted monoisocyanate is remained. According to the invention, trimethoxyhydrosilane and triallyl isocyanurate are used as raw materials, and the neutralization of the trimethoxyhydrosilane and the improvement of a catalyst greatly improve the hydrosilylation activity of the nitrogenous olefin, so that the content of a crude product after addition reaches more than 97% at one time, and a small amount of unreacted trimethoxyhydrosilane is removed only by simple distillation, and a tris (3-methoxysilylpropyl) isocyanurate product with the content of more than 99.0% is obtained.

3. The product has good appearance and low free chlorine. Because the reaction temperature is low, the appearance of the product does not turn yellow due to high-temperature reaction; the system does not use chloroalkoxysilane, does not produce sodium chloride salt, does not use monoisocyanate silane, so that the product does not contain free chlorine, does not have monoisocyanate residue harmful to human bodies, is more aging-resistant when being used as an adhesion promoter, and is more environment-friendly.

Detailed Description

Example 1

Adding 1g of clorine, 2g of sodium iron ethylene diamine tetraacetate and 30g of isopropanol into a 50ml three-neck flask which is provided with a condenser tube and is stirred by magnetic force, heating to 40-50 ℃, reacting for 4-5h, then cooling to room temperature, pouring the reaction solution into a triangular funnel which is paved with filter paper, filtering to obtain a transparent platinum catalyst, and quantifying to 30g by adding a small amount of isopropanol.

Adding 0.5% of cyclohexene oxide into the acidic trimethoxy hydrosilane with free chlorine of 200ppm, standing at normal temperature for 4h, detecting that the free chlorine is 6ppm, and detecting the content by gas chromatography to be 99.0%.

300g of 99.5% triallyl isocyanurate was added to a 1000ml four-neck flask equipped with magnetic stirring, a thermometer, a dropping funnel and a condenser, then 0.9g of the self-made catalyst was added, and the temperature was raised. 450g of neutralized trimethoxyhydrosilane was added to a dropping funnel and the dropwise addition of trimethoxyhydrosilane was started when the reaction temperature in the flask rose to 100 ℃. After 5min, the temperature of the reaction starts to rise, the reaction temperature is controlled at 100-. After the feeding is finished, continuing the heat preservation aging reaction for 1h, and sampling to detect the product content. Gas chromatography detection shows that the main content of the crude product is 97.8%, wherein unreacted trimethoxy hydrosilane is 1.4%, and a bis-addition byproduct, namely one molecule of triallyl isocyanurate and two molecules of trimethoxy hydrosilane, is 0.79%. And after the addition is finished, introducing the crude product into a distillation device, distilling to remove unreacted trimethyl, wherein the distillation temperature is 85-95 ℃, the vacuum degree is more than 0.098MPa, distilling for 6 hours, cooling, and filtering by a positive pressure filter under the protection of nitrogen to obtain the finished product of the tris (3-trimethoxysilylpropyl) isocyanurate. The product content was 99.2% by gas chromatography; measuring the total chlorine to be 5ppm by a total chlorine detector; the chroma of the product is 10 colors measured by a platinum-cobalt standard colorimetric method.

Example 2

Adding 1g of clorine, 2g of sodium iron ethylene diamine tetraacetate and 30g of isopropanol into a 50ml three-neck flask which is provided with a condenser tube and is stirred by magnetic force, heating to 40-50 ℃, reacting for 4-5h, then cooling to room temperature, pouring the reaction solution into a triangular funnel which is paved with filter paper, filtering to obtain a transparent platinum catalyst, and quantifying to 30g by adding a small amount of isopropanol.

Adding 0.5% of cyclohexene oxide into the acidic trimethoxy hydrosilane with the free chlorine of 400ppm, standing for 4h at normal temperature, detecting that the free chlorine is 15ppm, and detecting the content by gas chromatography to be 99.0%.

300g of 99.5% triallyl isocyanurate was added to a 1000ml four-neck flask equipped with magnetic stirring, a thermometer, a dropping funnel and a condenser, then 0.9g of the self-made catalyst was added, and the temperature was raised. 450g of neutralized trimethoxyhydrosilane was added to a dropping funnel and the dropwise addition of trimethoxyhydrosilane was started when the reaction temperature in the flask rose to 100 ℃. After 5min, the temperature of the reaction starts to rise, the reaction temperature is controlled at 100-. After the feeding is finished, continuing the heat preservation aging reaction for 1h, and sampling to detect the product content. Gas chromatography detection shows that the main content of the crude product is 97.3%, wherein unreacted trimethoxyhydrosilane is 1.5%, and 1.2% of di-addition by-products are obtained. And after the addition is finished, introducing the crude product into a distillation device, distilling to remove unreacted trimethyl, wherein the distillation temperature is 85-95 ℃, the vacuum degree is required to be more than 0.098MPa, after distillation is carried out for 6 hours, cooling, and filtering by a positive pressure filter under the protection of nitrogen to obtain the finished product of the tris (3-trimethoxysilylpropyl) isocyanurate. The product content was 98.8% by gas chromatography; measuring the total chlorine to be 10ppm by a total chlorine detector; the chroma of the product is 10 colors measured by a platinum-cobalt standard colorimetric method.

Example 3

Adding 1g of clorine, 4g of sodium iron ethylene diamine tetraacetate and 30g of isopropanol into a 50ml three-neck flask which is provided with a condenser tube and is stirred by magnetic force, heating to 40-50 ℃, reacting for 4-5h, then cooling to room temperature, pouring the reaction solution into a triangular funnel which is paved with filter paper, filtering to obtain a transparent platinum catalyst, and quantifying to 30g by adding a small amount of isopropanol.

Adding 0.5% of cyclohexene oxide into the acidic trimethoxy hydrosilane with free chlorine of 200ppm, standing at normal temperature for 4h, detecting that the free chlorine is 6ppm, and detecting the content by gas chromatography to be 99.0%.

300g of 99.5% triallyl isocyanurate was added to a 1000ml four-neck flask equipped with magnetic stirring, a thermometer, a dropping funnel and a condenser, then 0.9g of the self-made catalyst was added, and the temperature was raised. 450g of neutralized trimethoxyhydrosilane was added to a dropping funnel and the dropwise addition of trimethoxyhydrosilane was started when the reaction temperature in the flask rose to 100 ℃. After 2min, the temperature of the reaction starts to rise, the reaction temperature is controlled at 100-. After the feeding is finished, continuing the heat preservation aging reaction for 1h, and sampling to detect the product content. Gas chromatography detection shows that the main content of the crude product is 97.0%, wherein unreacted trimethoxyhydrosilane is 1.5%, and 1.48% of di-addition by-products are obtained. And after the addition is finished, introducing the crude product into a distillation device, distilling to remove unreacted trimethyl, wherein the distillation temperature is 85-95 ℃, the vacuum degree is required to be more than 0.098MPa, after distillation is carried out for 6 hours, cooling, and filtering by a positive pressure filter under the protection of nitrogen to obtain the finished product of the tris (3-trimethoxysilylpropyl) isocyanurate. The product content was 98.5% by gas chromatography; measuring the total chlorine to be 5ppm by a total chlorine detector; the chroma of the product is 10 colors measured by a platinum-cobalt standard colorimetric method.

Example 4

Adding 1g of clorine, 2g of sodium iron ethylene diamine tetraacetate and 30g of isopropanol into a 50ml three-neck flask which is provided with a condenser tube and is stirred by magnetic force, heating to 40-50 ℃, reacting for 4-5h, then cooling to room temperature, pouring the reaction solution into a triangular funnel which is paved with filter paper, filtering to obtain a transparent platinum catalyst, and quantifying to 30g by adding a small amount of isopropanol.

Adding 0.5% of cyclohexene oxide into the acidic trimethoxy hydrosilane with free chlorine of 200ppm, standing at normal temperature for 4h, detecting that the free chlorine is 6ppm, and detecting the content by gas chromatography to be 99.0%.

300g of 99.5% triallyl isocyanurate was added to a 1000ml four-neck flask equipped with magnetic stirring, a thermometer, a dropping funnel and a condenser, then 0.9g of the self-made catalyst was added, and the temperature was raised. 455g of neutralized trimethoxyhydrosilane was added to a dropping funnel and the dropwise addition of trimethoxyhydrosilane was started when the reaction temperature in the flask rose to 100 ℃. After 5min, the temperature of the reaction starts to rise, the reaction temperature is controlled at 100-. After the feeding is finished, continuing the heat preservation aging reaction for 1h, and sampling to detect the product content. Gas chromatography detection shows that the main content of the crude product is 97.1%, wherein unreacted trimethoxyhydrosilane is 2.0%, and a bis-addition byproduct is 0.8%. And after the addition is finished, introducing the crude product into a distillation device, distilling to remove unreacted trimethyl, wherein the distillation temperature is 85-95 ℃, the vacuum degree is required to be more than 0.098MPa, after distillation is carried out for 6 hours, cooling, and filtering by a positive pressure filter under the protection of nitrogen to obtain the finished product of the tris (3-trimethoxysilylpropyl) isocyanurate. The product content was 99.1% by gas chromatography; measuring the total chlorine to be 5ppm by a total chlorine detector; the chroma of the product is 10 colors measured by a platinum-cobalt standard colorimetric method.

Claims (1)

1. A method for synthesizing tris (3-trimethoxysilylpropyl) isocyanurate by an addition method is characterized by comprising the following steps:

1) and mixing chloroplatinic acid hexahydrate, isopropanol and ethylene diamine tetraacetic acid ferric sodium salt according to the mass ratio of 1: 30: 2-4, heating to 40-50 ℃, reacting for 4-5 hours, and filtering to remove a small amount of generated sodium chloride salt to obtain a platinum catalyst; standby;

2) adding 0.5 to 1 mass percent of cyclohexene oxide into the acidic trimethoxy hydrosilane, and standing for 4 to 6 hours at normal temperature until the free chlorine of the trimethoxy hydrosilane is reduced to less than 15 ppm; the total chlorine of the acidic trimethoxy silane is 200-400 ppm;

3) adding triallyl isocyanurate into a reactor, adding a spare platinum catalyst, heating to 100 ℃, then beginning to dropwise add neutralized trimethoxy hydrosilane to perform addition reaction, controlling the reaction temperature in the addition reaction at 110 ℃ with 100-; obtaining a crude product of the tris (3-trimethoxysilylpropyl) isocyanurate; the dosage of the platinum catalyst accounts for 0.3 to 0.5 percent of the mass of the fed triallyl isocyanurate; the molar ratio of trimethoxyhydrosilane to triallyl isocyanurate as the raw materials is 3.06-3.12: 1.0;

4) introducing the crude product into a distillation device, distilling to remove unreacted trimethoxy silane, wherein the distillation temperature is 85-95 ℃, the vacuum degree requirement is more than 0.098MPa, cooling after distilling for 6h, and filtering by a positive pressure filter under the protection of nitrogen to obtain the product; finished products of tris (3-trimethoxysilylpropyl) isocyanurate.