阅读说明：本技术 改进的有机聚硅氧烷合成方法 (Improved organopolysiloxane synthesis ) 是由 彭派潜 唐建振 吴光飞 游正林 陈巧站 宾家辉 于 2020-12-30 设计创作，主要内容包括：本发明公开一种改进的有机聚硅氧烷合成方法,是将具有碳碳双键的化合物与具有硅氢基的聚硅氧烷在缓冲溶液存在的条件下进行反应。该合成方法用于制备含羟基的有机聚硅氧烷,进而用于改性合成等,具有步骤简单、副产物少、溶剂用量少的优点。(The invention discloses an improved synthesis method of organopolysiloxane, which is to react a compound with carbon-carbon double bonds with polysiloxane with hydrosilyl in the presence of a buffer solution. The synthesis method is used for preparing the hydroxyl-containing organopolysiloxane, is further used for modification synthesis and the like, and has the advantages of simple steps, few byproducts and little solvent consumption.)

1. An improved process for the synthesis of organopolysiloxanes, characterized by the steps of:

under the protection of inert gas, mixing the reactant 1 with a buffer solution, the reactant 2 and a catalyst, and then heating for reaction to obtain organopolysiloxane;

a compound having at least one hydroxyl group and at least one carbon-carbon double bond in the molecular structure of the reactant 1; the reactant 2 is an organopolysiloxane having at least one hydrogen bond with silicon.

2. The improved process for the synthesis of organopolysiloxanes according to claim 1 wherein reactant 1 has at least one hydroxyl group in its molecular structure and at least one compound having at least one carbon-carbon double bond from the groupRadical (I)Or groupR₁Is H or CH₃。

3. The improved process for the synthesis of organopolysiloxanes according to claim 1 wherein the buffer solution is a buffer solution having a pH of from 2.5 to 6 at 37 ℃.

4. The improved process for the synthesis of organopolysiloxanes according to claim 1 wherein the temperature of the elevated temperature reaction is in the range of 50 to 90 ℃.

5. The improved organopolysiloxane synthesis process of claim 3, wherein the buffer solution is prepared from a weak acid having a dissociation constant of 2.5 to 6.5 at 25 ℃ in an aqueous solution, a salt of the weak acid prepared by neutralization reaction of the weak acid with a strong base, and an organic solvent.

6. The improved organopolysiloxane synthesis process of claim 3, wherein the buffer solution is prepared from a weak acid, a strong acid and an organic solvent, wherein the weak acid has a dissociation constant of 2.5 to 6.5 at 25 ℃ in aqueous solution.

7. The improved synthesis method of organopolysiloxane according to claim 5 or 6, wherein the organic solvent used for the preparation of the buffer solution is one or more of butanol, ethanol, acetone, and glycerol.

8. The improved organopolysiloxane synthesis process according to any of claims 1 to 4, wherein the mass ratio of the buffer solution to reactant 1 is (0.3 to 1.5): 1.

9. an improved organopolysiloxane synthesis process as claimed in any of claims 1 to 4, wherein reactant 1 is selected from one or more of the following compounds: ethylene glycol monoallyl ether, trimethylolpropane diallyl ether, diethylene glycol monoallyl ether, propylene glycol monoallyl ether, glycerol allyl ether, butanediol monoallyl ether.

10. The improved process for the synthesis of organopolysiloxanes as claimed in any of claims 1 to 4, wherein the number average molecular weight of reactant 2 is 200-5000.

11. The improved organopolysiloxane synthesis process of any of claims 1-4, wherein reactant 2 comprises a compound having a formula shown in formula 1:

in formula 1, m is an integer greater than 1, and R is the same or different alkyl, cycloalkyl, aryl, aralkyl, alkoxy, or haloalkyl.

12. The improved organopolysiloxane synthesis of claim 11, wherein the compound having the formula shown in formula 1 is prepared as follows: mixing cyclosiloxane, acid catalyst and organic solvent 1, heating to 65-75 ℃ for reaction for 2-4 h, adding trialkylsiloxidate and organic solvent 2, heating to 75-80 ℃ for reaction for 8-12 h, and adding dialkyl monohalosilane at 0 +/-5 ℃ for reaction for 18-24 h to obtain reactant 2.

Technical Field

The invention relates to the field of organic silicon synthesis, in particular to an improved organic polysiloxane synthesis method.

Technical Field

The organic silicon compound has good temperature resistance, hydrophobicity, weather resistance, aging resistance and ultraviolet resistance, can be used as a material independently or used for modifying other materials, and has continuously widened application in the chemical field. For example, the vinyl silicone oil has good weather resistance, aging resistance, ultraviolet resistance and flexibility, and can react with various organic materials such as polyurethane, acrylic acid and the like to prepare a high-performance anti-corrosion weather-resistant coating. The paint film formed by the acrylate emulsion still has defects in water resistance; the disadvantages of brittleness at low temperature and stickiness at high temperature also limit the use of acrylate emulsions. To solve this problem, the research on various composite structure emulsions, such as polyorganosiloxane PDMS modified silicone-acrylic emulsion, is now a hot research focus in high performance water-borne coatings. However, in the process of synthesizing the organosilicon modified acrylate emulsion, due to poor compatibility between PDMS and polyacrylate, phase separation is very easy to occur during synthesis and film formation, so that floating oil or coagulation is caused, the effective binding capacity is not high, and meanwhile, the large-scale phase separation causes low light transmittance of a coating film, so that the organosilicon property cannot be well reflected.

Patent CN105801769B describes a method for improving the anti-graffiti property of the surface by introducing vinyl silicone oil through emulsion polymerization, but the vinyl silicone oil has lower reactivity of double bonds, and the emulsion polymerization mode cannot obtain higher grafting efficiency, and has a certain risk to the stability of the coating. Modification of hydroxyl silicone oil is an effective way for modification of organic silicon, but the synthesis of the hydroxyl silicone oil at present has the defects of complex process and more side reactions, and the application of the modification scheme is influenced.

Disclosure of Invention

In order to solve the problems of the prior art, the present invention aims to provide an improved method for synthesizing organopolysiloxane, which is used for preparing hydroxyl-containing organopolysiloxane, further used for modification synthesis and the like, and has the advantages of simple steps, less by-products and less solvent consumption.

The technical scheme adopted by the invention is as follows:

an improved organopolysiloxane synthesis process comprising the steps of:

under the protection of inert gas, mixing the reactant 1 with a buffer solution, the reactant 2 and a catalyst, and heating to react to obtain organopolysiloxane;

a compound having at least one hydroxyl group and at least one carbon-carbon double bond in the molecular structure of the reactant 1; the reactant 2 is an organopolysiloxane having at least one hydrogen bond with silicon.

Preferably, the reactant 1 has a molecular structure having at least one hydroxyl group and a compound having at least one carbon-carbon double bond derived from a groupRadical (I)Or groupR₁Is H or CH₃。

Preferably, the reactant 1 is selected from one or more of the following compounds: ethylene glycol monoallyl etherTrimethylolpropane monoallyl etherTrimethylolpropane diallyl ether and diethylene glycol monoallyl etherPropylene glycol monoallyl etherGlycerol allyl etherButanediol monoallyl ether.

Preferably, the reactant 2 has a number average molecular weight of 200-.

Preferably, reactant 2 comprises a compound having the formula shown in formula 1:

in formula 1, m is an integer greater than 1, and R is the same or different alkyl, cycloalkyl, aryl, aralkyl, alkoxy, or haloalkyl.

The above-mentioned R's are the same or different alkyl groups, cycloalkyl groups, aryl groups, aralkyl groups, alkoxy groups or haloalkyl groups, the alkyl groups include methyl, ethyl, propyl or butyl groups, the cycloalkyl groups include cyclohexyl and cyclopentyl groups, the aryl groups include phenyl, tolyl and xylyl groups, the aralkyl groups include benzyl and phenethyl groups, the haloalkyl groups include 3, 3, 3-trifluoropropyl groups, and the alkoxy groups include methoxy, ethoxy and propoxy groups. The R is preferably methyl and phenyl.

The preparation of the compound having the formula shown in formula 1 can be performed with reference to the prior art. Preferably, the compound having the structural formula shown in formula 1 is prepared by the following method: mixing cyclosiloxane, acid catalyst and organic solvent 1, heating to 65-75 ℃ for reaction for 2-4 h, adding trialkylsiloxidate and organic solvent 2, heating to 75-80 ℃ for reaction for 8-12 h, and adding dialkyl monohalosilane at 0 +/-5 ℃ for reaction for 18-24 h to obtain reactant 2.

In the preparation method of the compound with the structural formula shown in the formula 1, the structural formula of the cyclosiloxane is shown in the specification

Wherein n is an integer from 3 to 6, R is as previously described and is selected, identically or differently, from alkyl, cycloalkyl, aryl, aralkyl, alkoxy or haloalkyl.

In the preparation method of the compound with the structural formula shown in the formula 1, alkyl in trialkylsiloxide is R as described above and is selected from alkyl, cycloalkyl, aryl, aralkyl, alkoxy or halogenated alkyl, trialkylsiloxide is selected from trialkylsiloxide lithium, trialkylsiloxide sodium or trialkylsiloxide potassium, the trialkylsiloxide is preferably trialkylsiloxide potassium, and the mass ratio of cyclosiloxane to trialkylsiloxide potassium is (6-20): 1, trialkylsilyloxidates as blocking agents, the amount used somewhat influencing the molecular weight of the final organopolysiloxane.

In the preparation method of the compound having the structural formula shown in formula 1, the acid catalyst can catalyze ring-opening polymerization of cyclosiloxane, and the specific substance is not particularly limited, and is preferably concentrated sulfuric acid, hydrochloric acid or trifluoromethanesulfonic acid, and preferably, the mass of the acid catalyst is 0.3% -1.8% of that of the cyclosiloxane.

In the preparation method of the compound with the structural formula shown in the formula 1, the halogenated group of the dialkyl monohalogenated silane is chlorine or bromine, preferably the dialkyl monohalogenated silane, and the alkyl in the dialkyl monohalogenated silane is R as described above and is selected from alkyl, cycloalkyl, aryl, aralkyl, alkoxy or halogenated alkyl. Preferably, in the method for preparing the compound having the structural formula shown in formula 1, the molar ratio of the dialkyl monohalosilane to the trialkylsilyloxide is (1-1.1): 1.

preferably, in the preparation method of the compound having the structural formula shown in formula 1, in the operation of mixing the cyclosiloxane, the acid catalyst and the organic solvent 1, the organic solvent 1 is a nonpolar solvent, such as toluene, xylene or cyclohexane, and the mass ratio of the organic solvent 1 to the cyclosiloxane is (0.3-2): 1.

preferably, in the preparation method of the compound having the structural formula shown in formula 1, in the operation of adding the trialkylsilyl silicon alkoxide and the organic solvent 2, the organic solvent 2 is a polar non-alcoholic solvent, and may be one or more of tetrahydrofuran and acetonitrile, and the mass ratio of the organic solvent 2 to the trialkylsilyl silicon alkoxide is (1-6): 1.

preferably, in the preparation method of the compound with the structural formula shown in formula 1, dialkyl monohalosilane is added to react for 18-24 hours, then the mixture is filtered, and then the organic solvent and low-boiling-point substances such as low molecules are removed by reduced pressure distillation at 80-90 ℃ to obtain a reactant 2, wherein the low molecules comprise side reaction products with low molecular weight, unreacted reactants and the like.

In the improved synthesis method of the organopolysiloxane, a reactant 1 is a compound with a carbon-carbon double bond and a hydroxyl group, a reactant 2 is the organopolysiloxane with a hydrogen group connected with silicon, and the carbon-carbon double bond and Si-H undergo an addition reaction in the reaction process, so that the hydroxyl group is introduced into the reactant 2, and an organopolysiloxane reaction product with a hydroxyl group is obtained.

Preferably, in the improved organopolysiloxane synthesis method, the buffer solution is a buffer solution with a pH value of 2.5-6 at 37 ℃, the buffer solution ionizes hydrogen ions to form stable hydrogen bonds with-OH, side reactions are effectively avoided, the buffer solution is too strong in acidity to inhibit normal addition reactions, or more catalysts need to be added, and the buffer solution cannot play a role in protection and cannot effectively avoid side reactions if too weak in acidity.

Preferably, the buffer solution is prepared from weak acid, salt of weak acid and organic solvent, and the dissociation constant of weak acid in water solution at 25 ℃ is 2.5-6.5. Preferably, the weak acid is selected from inorganic weak acid or organic weak acid, the inorganic weak acid is selected from carbonic acid, nitrous acid and the like, the organic weak acid is selected from alkyd, saturated fatty acid, aromatic acid or olefinic acid, and the alkyd can be glycolic acid, lactic acid and citric acid; examples of the aromatic acid include benzoic acid, phenylacetic acid, phthalic acid; the alkenoic acid may be acrylic acid, crotonic acid, oleic acid, and the salt of the weak acid is obtained by neutralizing a weak acid with a strong base, and is not particularly limited.

Specifically, the buffer solution is preferably obtained by mixing a solution of a weak acid with a solution of a salt of a weak acid and then diluting the mixture with an organic solvent, and more preferably, the concentration of the solution of the weak acid is 0.1 to 0.3mol/L, the concentration of the solution of the salt of the weak acid is 0.05 to 0.2mol/L, and the mixture is diluted to a pH value of 2.5 to 6 at 37 ℃.

Additionally, preferably, the buffer solution is prepared from weak acid, strong acid and organic solvent, and the dissociation constant of the weak acid in aqueous solution at 25 ℃ is 2.5-6.5. Preferably, the weak acid is an inorganic weak acid selected from carbonic acid, nitrous acid, etc., or an organic weak acid selected from alkyd, saturated fatty acid, aromatic acid, or olefinic acid, and the alkyd may be glycolic acid, lactic acid, citric acid; examples of the aromatic acid include benzoic acid, phenylacetic acid, phthalic acid; the olefinic acid may be acrylic acid, crotonic acid, or oleic acid.

Preferably, the organic solvent used for preparing the buffer solution is one or more of butanol, ethanol, acetone and glycerol.

Preferably, the mass ratio of the buffer solution to the reactant 1 is (0.3-1.5): 1, the invention adds the buffer solution, and hydrogen ions ionized from the buffer solution and hydroxyl in the reactant 1 form hydrogen bonds, thereby playing a role in protecting groups, effectively reducing the occurrence of side reactions and improving the reaction yield.

In the improved method for synthesizing the organopolysiloxane, the catalyst is a catalyst commonly used for the addition reaction of a carbon-carbon double bond and Si-H, is not particularly limited, and comprises a platinum catalyst, and preferably, the amount of the catalyst is 0.5-5% of the mass of the reactant 1.

In order to ensure the reaction rate, the molar ratio of the carbon-carbon double bond in the reactant 1 to the silicon-bonded hydrogen bond in the reactant 2 is greater than 1, so that the silicon-bonded hydrogen bond is completely reacted.

Preferably, the reaction product 1, the buffer solution, the reaction product 2 and the catalyst are mixed, heated, reacted, cooled, separated to obtain an organic layer, washed with water, and distilled under reduced pressure to remove the solvent, unreacted reaction products or low molecular weight by-products to obtain the organopolysiloxane.

Preferably, the temperature for mixing and heating the reactant 1, the buffer solution, the reactant 2 and the catalyst is 50-90 ℃. The reaction time of heating to 50-90 ℃ is not particularly limited, and the reaction time is adjusted according to the actual amount of reaction materials and the stirring condition until the viscosity of the reaction solution is not obviously changed.

The invention has the beneficial effects that: the invention effectively reduces the occurrence of side reaction by the improved synthesis method, saves the step of silazane protection, avoids the complex steps of acid washing, toluene solvent extraction and the like in the later period, simplifies the process and reduces the cost.

Detailed Description

The following specific examples are given to further illustrate the present invention.

The reactant 2 used in the examples is silicone oil containing a silylhydride at one end (hereinafter referred to as terminal hydrogen silicone oil), a preparation example of the reactant 2 is given below, the molecular weight of the terminal hydrogen silicone oil in examples 1-3 is calculated by gel permeation chromatography, the equipment is water1525, waters corporation, toluene is mobile phase, the flow rate is 1.0ml/min, polysiloxane is standard sample, the temperature of a column box is 35 ℃, the model of a separation column is Stry-agleo HT4, the column size is 7.8 × 300mm, the hydrogen content is measured at room temperature, the hydrogen content is the mass percentage content of the silylhydride connected with silicon, and the measuring method is HG-T4658 and 2014 determination of the active hydrogen content in textile dyeing and finishing auxiliary hydrogenous silicone oil.

Example 1

Adding 300g of octamethylcyclotetrasiloxane into a 1L three-neck flask, adding 5.4g of concentrated sulfuric acid and 600g of toluene, slowly heating to 75 ℃, reacting for 3 hours, adding 45g of potassium trimethylsilanolate and 270g of THF, heating to 80 ℃, reacting for 10 hours, cooling to room temperature, dropwise adding 33g of dimethylchlorosilane under an ice bath condition, reacting for 20 hours while keeping the temperature, filtering, distilling the filtrate under reduced pressure at 90 ℃ to remove low-boiling-point substances, and obtaining hydrogen-terminated silicone oil, wherein the number average molecular weight of the hydrogen-terminated silicone oil is 1000 and the hydrogen content of the hydrogen-terminated silicone oil is 0.10 percent.

Example 2

Adding 300g of octamethylcyclotetrasiloxane into a 1L three-neck flask, adding 0.9g of trifluoromethanesulfonic acid and 90g of toluene, slowly heating to 75 ℃, reacting for 3h, adding 15g of potassium trimethylsilanolate and 45g of THF, heating to 80 ℃, reacting for 10h, cooling to room temperature, dropwise adding 11g of dimethylchlorosilane under an ice bath condition, reacting for 20h while keeping the temperature, filtering, distilling the filtrate under reduced pressure at 90 ℃ to remove low-boiling-point substances, obtaining hydrogen-terminated silicone oil, and testing that the number average molecular weight of the hydrogen-terminated silicone oil is 2700 and the hydrogen content is 0.037%.

Example 3

Adding 300g of octamethylcyclotetrasiloxane into a 1L three-neck flask, adding 1.5g of concentrated sulfuric acid and 300g of toluene, slowly heating to 75 ℃, reacting for 3 hours, adding 25g of potassium trimethylsilanolate and 25g of THF, heating to 80 ℃, reacting for 10 hours, cooling to room temperature, dropwise adding 18.5g of dimethylchlorosilane under an ice bath condition, reacting for 20 hours while keeping the temperature, filtering, distilling the filtrate under reduced pressure at 90 ℃ to remove low-boiling-point substances, obtaining hydrogen-terminated silicone oil, and testing that the number average molecular weight of the hydrogen-terminated silicone oil is 1700 and the hydrogen content is 0.059%.

Examples of the preparation of organopolysiloxanes are given below, where the viscosity is a dynamic viscosity number at 25 ℃, test methods are referenced in GB/T2794-1995, and the hydroxyl group content is tested in GB/T12008.3-2009; and meanwhile, the hydrogen content of the reaction product is tested, and the reaction rate of hydrosilation is examined, wherein the test method is HG-T4658-2014 determination of the content of active hydrogen in the hydrogen-containing silicone oil as the textile dyeing and finishing auxiliary.

Example 4

Under the protection of nitrogen, 52g of ethylene glycol monoallyl ether, 55g of buffer solution, 150g of toluene, 500g of hydrogen-terminated silicone oil prepared in example 1 and 0.26g of 5000ppm of Karsted platinum catalyst are reacted at 55 ℃ for 6 hours, then the reaction mixture is cooled to room temperature, deionized water is added for washing for 5 times, then the reaction mixture is moved into a separating funnel for standing and layering, an upper organic layer is collected, and the organic layer is subjected to reduced pressure distillation to remove the solvent, unreacted reactants or low molecular byproducts, so that organopolysiloxane is obtained, wherein the yield is 98%, the viscosity is tested to be 20 mPas, the number average molecular weight is 1100, the hydroxyl content is 50mgKOH/g, and the hydrogen content is tested to be 0; the preparation method of the buffer solution comprises the following steps: 50ml of 0.2mol/L phthalic acid ethanol solution is mixed with 2.6ml of 0.2mol/L hydrogen chloride ethanol solution, and then the mixture is diluted into 200ml of buffer solution with ethanol, and the pH value is 3.8 at 37 ℃.

Example 5

Under the protection of nitrogen, 88g of trimethylolpropane monoallyl ether, 132g of buffer solution, 150g of toluene, 500g of hydrogen-terminated silicone oil prepared in example 1 and 4.4g of 5000ppm of Karster platinum catalyst react at 90 ℃ for 6 hours, then the temperature is reduced to room temperature, deionized water is added for washing for 5 times, the mixture is moved into a separating funnel for standing and layering, an upper organic layer is collected, and the organic layer is subjected to reduced pressure distillation to remove the solvent, unreacted reactants or low molecular byproducts, so that organopolysiloxane is obtained, wherein the yield is 99%, the viscosity is 86mPa & s, the number average molecular weight is 1200, the hydroxyl content is 93mgKOH/g, and the hydrogen content is 0; the preparation method of the buffer solution comprises the following steps: 38ml of a 0.1mol/L citric acid ethanol solution was mixed with 162ml of a 0.1mol/L sodium citrate glycerol solution to give 200ml of a buffer solution having a pH of 6.0 at 37 ℃.

Example 6

Under the protection of nitrogen, 66.7g of glycerol allyl ether, 70g of buffer solution, 150g of toluene, 500g of hydrogen-terminated silicone oil prepared in example 1 and 2g of 5000ppm of Karsted platinum catalyst are reacted at 80 ℃ for 6 hours, then the reaction temperature is reduced to room temperature, deionized water is added for washing for 5 times, then the mixture is moved into a separating funnel to be kept stand for layering, an upper organic layer is collected, and the organic layer is subjected to reduced pressure distillation to remove the solvent, unreacted reactants or low molecular byproducts, so that organopolysiloxane is obtained, wherein the yield is 99%, the viscosity is tested to be 80 mPas, the number average molecular weight is 1150, the hydroxyl content is 97mgKOH/g, and the hydrogen content is tested to be 0; the preparation method of the buffer solution comprises the following steps: 49ml of a 0.2mol/L ethanol solution of sodium acetate and 51ml of a 0.3mol/L ethanol solution of acetic acid were mixed to obtain 100ml of a buffer solution having a pH of 4.6 at 37 ℃.

Example 7

Under the protection of nitrogen, 19g of ethylene glycol monoallyl ether, 5.7g of buffer solution, 150g of toluene, 500g of hydrogen-terminated silicone oil prepared in example 2 and 0.5g of 5000ppm of Karsted platinum catalyst are reacted at 70 ℃ for 6h, then the temperature is reduced to room temperature, deionized water is added for washing for 5 times, the mixture is moved into a separating funnel for standing and layering, an upper organic layer is collected, and the organic layer is subjected to reduced pressure distillation to remove solvent, unreacted reactants or low molecular byproducts, so that organopolysiloxane is obtained, wherein the yield is 98%, the viscosity is tested to be 52 mPas, the number average molecular weight is 2800, the hydroxyl content is 19mgKOH/g, and the hydrogen content is tested to be 0, and the preparation method of the buffer solution comprises the following steps: 7.5ml of a 0.2mol/L ethanol solution of sodium acetate and 92.5ml of a 0.3mol/L ethanol solution of acetic acid were mixed to obtain 100ml of a buffer solution having a pH of 2.6 at 37 ℃.

Example 8

Under the protection of nitrogen, 30.5g of ethylene glycol monoallyl ether, 31g of buffer solution, 150g of toluene, 500g of hydrogen-terminated silicone oil prepared in example 3 and 1g of 5000ppm of Karsted platinum catalyst are reacted at 60 ℃ for 6 hours, then the reaction temperature is reduced to room temperature, deionized water is added for washing for 5 times, the mixture is moved into a separating funnel and is kept stand for layering, an upper organic layer is collected, and the organic layer is subjected to reduced pressure distillation to remove the solvent, unreacted reactants or low molecular byproducts, so that organopolysiloxane is obtained, the yield is 98%, the viscosity is tested to be 33 mPas, the number average molecular weight is 1800, the hydroxyl content is 31mgKOH/g, and the hydrogen content is tested to be 0, wherein the preparation method of the buffer solution is as follows: 18ml of a 0.2mol/L solution of sodium acetate in acetone and 82ml of a 0.3mol/L solution of acetic acid in ethanol are mixed and diluted with ethanol to 200ml of a buffer solution having a pH of 4.0 at 37 ℃.

The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.