Hexaphenylcyclotrisiloxane and synthesis method thereof
By using diphenyl dimethoxysilane to undergo reflux reaction with acetic acid and a strong acid catalyst, combined with the methods of reduced pressure distillation, dropping reaction and recrystallization purification, the problem of high cost of synthesis of hexophenyl cyclotrisiloxane in the prior art is solved, and the efficient synthesis of high-purity products is achieved.
Patent Information
- Application Number
- CN202411495887.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-25
- Publication Date
- 2025-02-25
AI Technical Summary
The prior art lacks an effective synthesis method for hexaphenylcyclotrisiloxane, and the cost of using diphenylsilicol is relatively high.
Reflux reaction was carried out with diphenyldimethoxysilane with acetic acid and a strong acid catalyst, followed by distillation under reduced pressure to remove by-products, then organic solvent was added and acetic acid and acetic anhydride were added dropwise, and finally, high-purity hexophenylcyclotrisiloxane was purified by cooling crystallization, filtration and recrystallization.
The efficient synthesis of hexophenylcyclotrisiloxane is achieved, reducing costs, and obtaining a high-purity product through recrystallization separation and purification.
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of organic chemistry, and in particular to hexaphenylcyclotrisiloxane and a synthesis method thereof. Background Art
[0002] Hexaphenylcyclotrisiloxane is a white granular solid at room temperature with a high melting point. It is insoluble in water but soluble in many organic solvents. It is an intermediate of organic silicon materials and has similar appearance and uses to octaphenylcyclotetrasiloxane. It can be used to synthesize high molecular polymers, for example, it can be used as a raw material to synthesize phenyl silicone oil, phenyl silicone resin, phenyl silicone rubber, etc.; it can also be used as a modified intermediate for polyurethane resin, epoxy resin, etc., giving new products properties such as high and low temperature resistance, radiation resistance, and aging resistance.
[0003] Hexaphenylcyclotrisiloxane can be obtained by cyclization of diphenylsilanediol with an acid or base catalyst, but there is no mature technical solution and the cost of using diphenylsilanediol is high. Therefore, a method for synthesizing hexaphenylcyclotrisiloxane is developed. Summary of the invention
[0004] In view of the above technical problems, the technical solution adopted by the present invention is: a method for synthesizing hexaphenylcyclotrisiloxane, comprising the following steps: step 1: adding diphenyldimethoxysilane to a reaction container equipped with a reflux device, adding mixed acetic acid and a strong acid catalyst under stirring conditions, heating to 55-65°C, and then maintaining the temperature at 55-65°C for reflux reaction for 1-2h; step 2: after the reflux reaction is completed, switching to reduced pressure distillation to remove most of the generated methyl acetate and methanol; step 3: adding an organic solvent, heating to 50-55°C, dripping acetic acid and acetic anhydride, controlling the temperature during the dripping process at 50-55°C, and maintaining the temperature for reaction for 1h after completion; step 4: cooling and crystallizing, filtering and drying with a Buchner funnel, adding an organic solvent to the filtrate, washing with water to remove acid, and concentrating the crystals, filtering the crystals and concentrating the crystals for multiple recrystallization and purification to obtain high-purity hexamethylcyclotrisiloxane.
[0005] Preferably, in step 1, the mass ratio of diphenyldimethoxysilane to acetic acid is 1:0.12-0.18.
[0006] Preferably, in step 1, the amount of the strong acid catalyst used is 500 to 1500 ppm of the total mass of diphenyldialkoxysilane and acetic acid.
[0007] Preferably, in step 1, the strong acid catalyst is sulfuric acid, hydrochloric acid or trifluoromethanesulfonic acid.
[0008] Preferably, in step 2, during the reduced pressure distillation process, the vacuum degree is -0.07 to -0.09 MPa, the temperature is 50 to 60° C., and the time is 0.5 to 1 h.
[0009] Preferably, in step 3, the organic solvent is an aromatic or alkane solvent, and the mass ratio of diphenyldimethoxysilane, the organic solvent, acetic acid and acetic anhydride is 1:0.8-5:0.06-0.13:0.1-0.21.
[0010] Preferably, the aromatic solvent is toluene or o-xylene.
[0011] Preferably, in step 4, the vacuum degree during concentration and crystallization is -0.095 to -0.098 MPa, the temperature is 70-80°C, and the time is 1-2 h.
[0012] The present invention also provides hexaphenylcyclotrisiloxane prepared by the method described above; the hexaphenylcyclotrisiloxane is a white granular crystal.
[0013] Compared with the prior art, the invention has the following beneficial effects: the purpose of the invention is to provide a method for synthesizing hexaphenylcyclotrisiloxane. The method uses diphenyldimethoxysilane and acetic acid as reaction raw materials, a strong acid as a catalyst, removes methyl acetate and methanol by reduced pressure distillation after the reflux reaction, then adds an organic solvent, drips acetic acid and acetic anhydride, and reacts by heat preservation after the dripping. After the reaction, the reaction is cooled and crystallized, filtered and dried with a Buchner funnel, the filtrate is added with an organic solvent, washed with water to remove acid, and then concentrated and crystallized. The products obtained by filtering and concentrating the crystals are mainly hexaphenylcyclotrisiloxane and octaphenylcyclotetrasiloxane, which can be separated and purified by recrystallization to obtain high-purity hexaphenylcyclotrisiloxane. DETAILED DESCRIPTION
[0014] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are partial embodiments of the present invention, rather than all embodiments.
[0015] The present invention provides a method for synthesizing hexaphenylcyclotrisiloxane, the steps of the method are as follows: Step 1: Add diphenyldimethoxysilane to a reaction vessel equipped with a reflux device, add the mixed acetic acid and strong acid catalyst under stirring, raise the temperature to 55-65° C., and then maintain the temperature at 55-65° C. for reflux reaction for 1-2 hours; Step 2: After the reflux reaction is completed, the reaction is performed by vacuum distillation to remove most of the produced methyl acetate and methanol; Step 3: Add an organic solvent, raise the temperature to 50-55°C, add acetic acid and acetic anhydride dropwise, control the temperature at 50-55°C during the addition process, and keep the temperature for reaction for 1 hour after completion; Step 4: Cool the crystals, filter and dry them using a Buchner funnel, add an organic solvent to the filtrate, wash with water to remove the acid, and then concentrate the crystals. The filtered crystals and concentrated crystals are purified by recrystallization to obtain high-purity hexaphenylcyclotrisiloxane.
[0016] Example 1: (1) Reflux reaction step: add 366.54 g (1.5 mol) of diphenyldimethoxysilane to a reaction vessel equipped with a reflux device, add 60.05 g (1 mol) of acetic acid and 0.64 g (1500 ppm) of trifluoromethanesulfonic acid mixed under stirring conditions, raise the temperature to 55-65°C, and then maintain the temperature at 55-65°C for reflux reaction for 2 hours; (2) Vacuum distillation step: After the reflux reaction is completed, switch to vacuum distillation with a vacuum degree of -0.08 to -0.09 MPa, a temperature of 50 to 60°C, and a time of 0.5 to 1 h to remove most of the methyl acetate and methanol produced. At this time, the material will turn white and crystals will appear; (3) Dropwise reaction step: add 300 g of toluene, raise the temperature to 50-55°C, dropwise add 30.03 g (0.5 mol) of acetic acid, and the dropwise addition time is 20-40 min; then dropwise add 51.05 g (0.5 mol) of acetic anhydride, and the dropwise addition time is 40-80 min. The temperature during the dropwise addition process is controlled at 50-55°C. After completion, keep the temperature for reaction for 1 hour; (4) Crystallization and filtration step: cooling and crystallization, filtering and drying with a Buchner funnel, obtaining 165.42 g of product, the content of hexaphenylcyclotrisiloxane in the liquid phase was 88%, and the content of octaphenylcyclotetrasiloxane was 11%; adding 200 g of toluene to the filtrate, washing with water to remove acid, and concentrating and crystallizing, the vacuum degree was -0.095 to -0.098 MPa, the temperature was 70 to 80°C, and the time was 1 to 2 h, and the solvent toluene was removed by reduced pressure distillation. When a large amount of white solid appeared, the concentration was stopped, cooling and crystallization, filtering and drying with a Buchner funnel, obtaining 111.12 g of product, the content of hexaphenylcyclotrisiloxane in the liquid phase was 57%, and the content of octaphenylcyclotetrasiloxane was 32%; filtering and concentrating the crystals and purifying by recrystallization, obtaining 179.79 g of hexaphenylcyclotrisiloxane with a purity of 99.6%, and a yield of 60.54%; and 53.75 g of octaphenylcyclotetrasiloxane with a purity of 99%, and a yield of 18.07%.
[0017] Example 2: (1) Reflux reaction step: add 366.54 g (1.5 mol) of diphenyldimethoxysilane to a reaction vessel equipped with a reflux device, add 54.05 g (0.9 mol) of acetic acid and 0.63 g (1500 ppm) of trifluoromethanesulfonic acid mixed under stirring conditions, raise the temperature to 55-65°C, and then maintain the temperature at 55-65°C for reflux reaction for 2 hours; (2) Vacuum distillation step: After the reflux reaction is completed, switch to vacuum distillation with a vacuum degree of -0.08 to -0.09 MPa, a temperature of 50 to 60°C, and a time of 0.5 to 1 h to remove most of the methyl acetate and methanol produced. At this time, the material will turn white and crystals will appear; (3) Dropwise reaction step: add 300 g of toluene, raise the temperature to 50-55°C, dropwise add 36.03 g (0.6 mol) of acetic acid, and the dropwise addition time is 20-40 min; then dropwise add 61.25 g (0.6 mol) of acetic anhydride, and the dropwise addition time is 40-80 min. The temperature during the dropwise addition process is controlled at 50-55°C. After completion, keep the temperature for reaction for 1 hour; (4) Crystallization and filtration step: cooling and crystallization, filtering and drying with a Buchner funnel, obtaining 172.26 g of product, the content of hexaphenylcyclotrisiloxane in the liquid phase was 84%, and the content of octaphenylcyclotetrasiloxane was 15%; adding 200 g of toluene to the filtrate, washing with water to remove acid, and concentrating and crystallizing, the vacuum degree was -0.095 to -0.098 MPa, the temperature was 70 to 80°C, and the time was 1 to 2 h, and the solvent toluene was removed by reduced pressure distillation. When a large amount of white solid appeared, the concentration was stopped, cooling and crystallization, filtering and drying with a Buchner funnel, obtaining 109.74 g of product, the content of hexaphenylcyclotrisiloxane in the liquid phase was 55%, and the content of octaphenylcyclotetrasiloxane was 33%; filtering and concentrating the crystals and purifying by recrystallization, obtaining 176.12 g of hexaphenylcyclotrisiloxane with a purity of 99.5%, and a yield of 59.21%; and 62.05 g of octaphenylcyclotetrasiloxane with a purity of 99%, and a yield of 20.86%.
[0018] Example 3: (1) Reflux reaction step: add 366.54 g (1.5 mol) of diphenyldimethoxysilane to a reaction vessel equipped with a reflux device, add 45.04 g (0.9 mol) of acetic acid and 0.62 g (1500 ppm) of trifluoromethanesulfonic acid mixed under stirring conditions, raise the temperature to 55-65°C, and then maintain the temperature at 55-65°C for reflux reaction for 2 hours; (2) Vacuum distillation step: After the reflux reaction is completed, switch to vacuum distillation with a vacuum degree of -0.08 to -0.09 MPa, a temperature of 50 to 60°C, and a time of 0.5 to 1 h to remove most of the methyl acetate and methanol produced. At this time, the material will turn white and crystals will appear; (3) Dropwise reaction step: add 300 g of toluene, raise the temperature to 50-55°C, dropwise add 45.04 g (0.75 mol) of acetic acid, and the dropwise addition time is 20-40 min; then dropwise add 76.57 g (0.75 mol) of acetic anhydride, and the dropwise addition time is 40-80 min. The temperature during the dropwise addition process is controlled at 50-55°C. After completion, keep the temperature for reaction for 1 hour; (4) Crystallization and filtration step: cooling and crystallization, filtering and drying with a Buchner funnel, obtaining 153.45 g of product, the content of hexaphenylcyclotrisiloxane in the liquid phase was 82%, and the content of octaphenylcyclotetrasiloxane was 17%; adding 200 g of toluene to the filtrate, washing with water to remove acid, and concentrating and crystallizing, the vacuum degree was -0.095 to -0.098 MPa, the temperature was 70 to 80°C, and the time was 1 to 2 h, and the solvent toluene was removed by reduced pressure distillation. When a large amount of white solid appeared, the concentration was stopped, cooling and crystallization, filtering and drying with a Buchner funnel, obtaining 105.68 g of product, the content of hexaphenylcyclotrisiloxane in the liquid phase was 53%, and the content of octaphenylcyclotetrasiloxane was 36%; filtering and concentrating the crystals and purifying by recrystallization, obtaining 181.84 g of hexaphenylcyclotrisiloxane with a purity of 99.2%, and a yield of 61.13%; and 64.13 g of octaphenylcyclotetrasiloxane with a purity of 99%, and a yield of 21.56%.
[0019] Example 4: (1) Reflux reaction step: add 366.54 g (1.5 mol) of diphenyldimethoxysilane to a reaction vessel equipped with a reflux device, add 66.06 g (1.1 mol) of acetic acid and 0.61 g (1400 ppm) of trifluoromethanesulfonic acid mixed under stirring, raise the temperature to 50-55°C, and then maintain the temperature at 55-65°C for reflux reaction for 2 hours; (2) Vacuum distillation step: After the reflux reaction is completed, switch to vacuum distillation with a vacuum degree of -0.07 to -0.08 MPa, a temperature of 50 to 60°C, and a time of 0.5 to 1 h to remove most of the methyl acetate and methanol produced. At this time, the material will turn white and crystals will appear; (3) Dropwise reaction step: add 300 g of toluene, raise the temperature to 50-55°C, dropwise add 31.03 g (0.5 mol) of acetic acid, and the dropwise addition time is 20-40 min; then dropwise add 51.05 g (0.5 mol) of acetic anhydride, and the dropwise addition time is 40-80 min. The temperature during the dropwise addition process is controlled at 50-55°C. After completion, keep the temperature for reaction for 1 hour; (4) Crystallization and filtration step: cooling and crystallization, filtering and drying with a Buchner funnel, obtaining 169.85 g of product, the content of hexaphenylcyclotrisiloxane in the liquid phase was 86%, and the content of octaphenylcyclotetrasiloxane was 13%; adding 200 g of toluene to the filtrate, washing with water to remove acid, and concentrating and crystallizing, the vacuum degree was -0.095 to -0.098 MPa, the temperature was 70 to 80°C, and the time was 1 to 2 h, and the solvent toluene was removed by reduced pressure distillation. When a large amount of white solid appeared, the concentration was stopped, cooling and crystallization, filtering and drying with a Buchner funnel, obtaining 112.31 g of product, the content of hexaphenylcyclotrisiloxane in the liquid phase was 55%, and the content of octaphenylcyclotetrasiloxane was 38%; filtering and concentrating the crystals and purifying by recrystallization, obtaining 157.67 g of hexaphenylcyclotrisiloxane with a purity of 99.3%, and a yield of 52.67%; and 71.55 g of octaphenylcyclotetrasiloxane with a purity of 99%, and a yield of 24.06%.
[0020] Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.
Claims
1. A method for synthesizing hexaphenylcyclotrisiloxane, characterized in that: The steps include: Step 1: Add diphenyldimethoxysilane to a reaction vessel equipped with a reflux device, add the mixed acetic acid and strong acid catalyst under stirring, raise the temperature to 55-65° C., and then maintain the temperature at 55-65° C. for reflux reaction for 1-2 hours; Step 2: After the reflux reaction is completed, the reaction is performed by vacuum distillation to remove most of the produced methyl acetate and methanol; Step 3: Add an organic solvent, raise the temperature to 50-55°C, add acetic acid and acetic anhydride dropwise, control the temperature at 50-55°C during the addition process, and keep the temperature for reaction for 1 hour after completion; Step 4: Cool the crystals, filter and dry them using a Buchner funnel, add an organic solvent to the filtrate, wash with water to remove the acid, and then concentrate the crystals. The filtered crystals and concentrated crystals are purified by recrystallization to obtain high-purity hexaphenylcyclotrisiloxane.
2. A method for synthesizing hexaphenylcyclotrisiloxane according to claim 1, characterized in that: In the step 1, the mass ratio of diphenyldimethoxysilane to acetic acid is 1:0.12-0.
18.
3. A method for synthesizing hexaphenylcyclotrisiloxane according to claim 1, characterized in that: In the step 1, the amount of the strong acid catalyst used is 500 to 1500 ppm of the total mass of diphenyldialkoxysilane and acetic acid.
4. A method for synthesizing hexaphenylcyclotrisiloxane according to claim 1, characterized in that: In step 1, the strong acid catalyst is sulfuric acid, hydrochloric acid or trifluoromethanesulfonic acid.
5. A method for synthesizing hexaphenylcyclotrisiloxane according to claim 1, characterized in that: In the step 2, during the reduced pressure distillation, the vacuum degree is -0.07 to -0.09 MPa, the temperature is 50 to 60° C., and the time is 0.5 to 1 h.
6. A method for synthesizing hexaphenylcyclotrisiloxane according to claim 1, characterized in that: In step 3, the organic solvent is an aromatic or alkane solvent, and the mass ratio of diphenyldimethoxysilane, the organic solvent, acetic acid and acetic anhydride is 1:0.8-5:0.06-0.13:0.1-0.
21.
7. A method for synthesizing hexaphenylcyclotrisiloxane according to claim 6, characterized in that: In the step 3, the aromatic solvent is toluene or o-xylene.
8. A method for synthesizing hexaphenylcyclotrisiloxane according to claim 1, characterized in that: During the concentration and crystallization process in step 4, the vacuum degree is -0.095 to -0.098 MPa, the temperature is 70-80°C, and the time is 1-2 hours.
9. Hexaphenylcyclotrisiloxane prepared by the method according to any one of claims 1 to 8.
10. The hexaphenylcyclotrisiloxane according to claim 9, characterized in that: The hexaphenylcyclotrisiloxane is a granular crystal.