Application of photocatalyst in preparation of epoxy silicone oil
By using chloroplatinic acid as a photocatalyst in the preparation of epoxy silicone oil, decompose by-products under sunlight, the color problems and high viscosity decolorization problems caused by high-temperature catalyst decomposition are solved, and the efficient preparation of colorless transparent epoxy silicone oil is achieved. Avoid environmental pollution and increase in production costs.
Patent Information
- Application Number
- CN202411518084.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-29
- Publication Date
- 2025-01-03
AI Technical Summary
In the existing preparation methods for epoxy silicone oil, the decomposition of the catalyst under high temperature conditions leads to side reactions, the product color turns brown, and decolorizing agents such as activated carbon are required, which leads to environmental pollution and operation difficulties, especially the decolorization of high-viscosity epoxy silicone oil is difficult to achieve.
Using chloroplatinic acid as a photocatalyst, decomposes the by-products in epoxy silicone oil under sunlight, avoids physical adsorption methods such as activated carbon, and converts brown epoxy silicone oil into colorless through photocatalysts, combining specific reaction steps and catalyst usage Optimize to ensure product purity and viscosity control.
The preparation of colorless transparent epoxy silicone oil is realized, which avoids environmental pollution and additional adsorption and filtration steps in production, improves product purity and yield, simplifies process operations, saves production costs, and controls molecular weight and viscosity.
Smart Images
Figure CN119241847A_ABST
Abstract
Description
Technical Field
[0001] This patent relates to the application field of photocatalysts, and specifically to the application of a photocatalytic reaction in the preparation and purification of epoxy silicone oil. Background Art
[0002] Epoxy silicone oil is a key raw material widely used in the fields of textile industry, polyacrylonitrile carbon fiber precursor oil, high temperature resistant coating, sealant and silicone rubber. There are usually two methods for preparing epoxy silicone oil. One method is to first prepare hydrogenated silicone oil by Lewis acid catalysis D4, and then prepare epoxy silicone oil by silylation reaction with allyl glycidyl ether under chloroplatinic acid catalyst. This method needs to remove Lewis acid after the preparation of epoxy silicone oil. In addition, the silylation reaction of hydrogenated silicone oil with allyl glycidyl ether is not thorough, and the residual silicon hydrogen is easy to undergo self-crosslinking reaction, which is not conducive to the storage stability of epoxy silicone oil; the second method is to prepare epoxy silicone oil by base catalysis D4 and epoxy double head. The base catalyst used is generally sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, etc. When preparing medium and low molecular weight epoxy silicone oil, tetramethylammonium hydroxide is usually used as a catalyst, and the catalyst is removed by high temperature decomposition of tetramethylammonium hydroxide after the reaction. However, side reactions are prone to occur in the process of decomposing tetramethylhydroxyamine catalyst under high temperature conditions, resulting in the product color turning brown. In order to prepare colorless epoxy silicone oil, activated carbon, activated clay, etc. are usually used to physically adsorb and decolorize the silicone oil. Since the amount of adsorbent used is 20-30%, it will cause environmental pollution. In order to avoid the use of adsorbents such as activated carbon for decolorization, this patent develops a photocatalyst. Under sunlight, the brown epoxy silicone oil can be converted into colorless, avoiding environmental pollution and multiple production steps such as adsorption and filtration. Summary of the invention
[0003] In view of the shortcomings of the prior art, the present invention aims to provide a photocatalyst that can decompose the by-products produced during the preparation of epoxy silicone oil under sunlight, and the product color is converted from brown to colorless, avoiding the use of decolorizing agents such as activated carbon and activated clay. In addition, for the preparation of high-viscosity epoxy silicone oil, the traditional decolorizing method using decolorizing agents such as activated carbon and activated clay encounters process operation difficulties, that is, the operation of filtering and removing the decolorizing agent after decolorizing the high-viscosity epoxy silicone oil is very difficult. Therefore, it is very necessary to invent a photocatalyst that decomposes the by-products through sunlight irradiation to achieve the purpose of purifying epoxy silicone oil, and it also has scientific and technological innovation value.
[0004] Another object of the present invention is to provide a method for preparing epoxy silicone oils of different viscosities, which is colorless and transparent.
[0005] A photocatalyst is used in the preparation of epoxy silicone oil, characterized in that chloroplatinic acid is used as a photocatalyst to decompose the byproducts produced in the synthesis of epoxy silicone oil under sunlight to prepare colorless epoxy silicone oil, avoiding the use of physical adsorption methods such as activated carbon and activated clay for decolorization. The specific steps are as follows:
[0006] 1) Heating octamethylcyclotetrasiloxane (D4) to 75°C-80°C, adding tetramethylammonium hydroxide catalyst, and reacting for 1-3 hours;
[0007] 2) Add epoxy double head (1,3-bis (3-glycidyl ether oxypropane) and D4 mixture, 75℃
[0008] -80℃ for 3-6 hours;
[0009] 3) Raise the temperature to 115-120°C and react for 3-6 hours;
[0010] 4) Take the sample and let it stand to observe whether there is phase separation;
[0011] 5) After phase separation, tetramethylammonium hydroxide catalyst is added and the reaction is continued at 115-120°C;
[0012] 6) Raise the temperature to 140-150°C and react for 2-3 hours;
[0013] 7) Cooling to below 60°C and adding photocatalyst;
[0014] 8) After high-speed stirring, discharge the material;
[0015] 9) Sunlight exposure.
[0016] In the step 1), a polydimethylsiloxane cationic initiator is prepared by reacting D4 with tetramethylammonium hydroxide;
[0017] In the steps 2) to 3), the polydimethylsiloxane cationic initiator prepared in step 1) further initiates the ring-opening reaction of D4, the molecular weight of polydimethylsiloxane increases, the epoxy double-capping simultaneously terminates the further chain extension reaction of polydimethylsiloxane, and the amount of tetramethylammonium hydroxide catalyst affects the conversion rate of D4;
[0018] In the steps 4) to 5), it is determined whether the reaction between D4 and the epoxy double end cap is complete, and then tetramethylammonium hydroxide catalyst is added to induce the reaction between the unreacted D4 and the epoxy double end cap to increase the conversion rate of D4;
[0019] In the step 6), the reaction is carried out at 140-150° C. to thermally decompose the tetramethylammonium hydroxide catalyst;
[0020] In the step 7), the photocatalyst is chloroplatinic acid, and the amount used accounts for 1-5 ppm of the total product.
[0021] In the step 9), the prepared epoxy silicone oil is exposed to sunlight to photodecompose the epoxy silicone oil byproducts prepared in the steps 1) to 6).
[0022] As a further optimization of the present invention, the amount of tetramethylammonium hydroxide used in step 1) is 0.01%-0.06% of the mass of the epoxy silicone oil.
[0023] As a further optimization of the present invention, steps 4) and 5) are necessary preparation steps to ensure that the conversion rate of D4 is greater than 95%, the prepared epoxy silicone oil is clear and transparent, and the unreacted epoxy double head residue is avoided.
[0024] Beneficial Effects
[0025] In view of the shortcomings of the existing technology, this patent invented a photocatalyst, chloroplatinic acid, which can decompose the by-products produced in the preparation process of epoxy silicone oil under sunlight, and the color of epoxy silicone oil changes from brown to colorless. There is no need for activated carbon, activated clay and other decolorizers to decolorize epoxy silicone oil, avoiding environmental pollution and the use of additional adsorption, filtration and other equipment in production, effectively saving production costs, and at the same time, it can also improve product yield. A small amount of unreacted D4 can be recycled. In addition, using photocatalysts and photodecomposition reactions, epoxy silicone oils of different viscosities can be prepared with a purity of 100% and a controllable molecular weight from hundreds to thousands. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 Chemical reaction formula for preparing epoxy silicone oil and the process of photocatalytic decomposition byproducts DETAILED DESCRIPTION
[0027] Embodiment 1:
[0028] In a 3-liter glass reactor equipped with a nitrogen inlet and a nitrogen outlet, 516 grams of D4 were added, heated and mechanically stirred, the temperature was raised to 75-80°C, 0.4 grams of tetramethylammonium hydroxide catalyst was added, and after reacting for 1 hour, 516 grams of D4 and 507 grams of epoxy double-end mixture were added, and the mixture was reacted at 75-80°C for 3 hours, and then the temperature was raised to 115-120°C and kept at a constant temperature for 3 hours, and then the solution in the glass reactor was observed to be transparent. If the mixture solution was turbid, 0.2-0.4 grams of tetramethylammonium hydroxide catalyst was added, and the mixture was reacted at 115-120 for 2 hours, and the mixture was heated to 140-150°C to decompose the tetramethylammonium hydroxide catalyst. After cooling to 60°C, 1-5ppm chloroplatinic acid isopropanol solution was added, and the product changed from brown to colorless under sunlight. A small amount of precipitate was removed by filtration to obtain colorless and transparent epoxy silicone oil, and the conversion rate of D4 was 100%.
[0029] Embodiment 2:
[0030] In a 3-liter glass reactor equipped with a nitrogen inlet and a nitrogen outlet, 516 grams of D4 were added, heated and mechanically stirred, the temperature was raised to 75-80°C, 0.4 grams of tetramethylammonium hydroxide catalyst was added, and after reacting for 1 hour, 516 grams of D4 and 507 grams of epoxy double-capped containing chloroplatinic acid were added, and the reaction was carried out at 75-80°C for 3 hours, and then the temperature was raised to 115-120°C and kept at a constant temperature for 3 hours, and then the solution in the glass reactor was observed to be transparent. If the mixture solution was turbid, 0.2-0.4 grams of tetramethylammonium hydroxide catalyst was added, and the reaction was carried out at 115-120 for 2 hours, and the temperature was raised to 140-150°C to decompose the tetramethylammonium hydroxide catalyst. After cooling to 60°C, the product was discharged from the reactor and exposed to sunlight. The product changed from brown to colorless. A small amount of precipitate was removed by filtration to obtain colorless and transparent epoxy silicone oil. The conversion rate of D4 was 100%.
[0031] Embodiment 3:
[0032] In a 3-liter glass reactor equipped with a nitrogen inlet and a nitrogen outlet, 516 grams of D4 were added, heated and mechanically stirred, the temperature was raised to 75-80°C, 0.4 grams of tetramethylammonium hydroxide catalyst was added, and after reacting for 1 hour, 516 grams of D4 and 200 grams of epoxy double-capped containing chloroplatinic acid were added, and the reaction was carried out at 75-80°C for 3 hours, and then the temperature was raised to 115-120°C and kept at a constant temperature for 3 hours, and then the solution in the glass reactor was observed to be transparent. If the mixture solution was turbid, 0.2-0.4 grams of tetramethylammonium hydroxide catalyst was added, and the reaction was carried out at 115-120 for 2 hours, and the temperature was raised to 140-150°C to decompose the tetramethylammonium hydroxide catalyst. After cooling to 60°C, the product was discharged from the reactor and exposed to sunlight. The product changed from brown to colorless. A small amount of precipitate was removed by filtration to obtain colorless and transparent epoxy silicone oil. The conversion rate of D4 was 96%.
Claims
1. An application of a photocatalyst in the preparation of epoxy silicone oil, characterized in that: Using chloroplatinic acid as a photocatalyst, the byproducts produced in the synthesis of epoxy silicone oil can be decomposed under sunlight to prepare colorless epoxy silicone oil, avoiding the use of physical adsorption methods such as activated carbon and activated clay for decolorization. The specific steps are as follows: 1) Heating octamethylcyclotetrasiloxane (D4) to 75°C-80°C, adding tetramethylammonium hydroxide catalyst, and reacting for 1-3 hours; 2) Add epoxy double head (1,3-bis (3-glycidyl ether oxypropane) and D4 mixture, react at 75 ° C -80 ° C for 3-6 hours; 3) Raise the temperature to 115-120°C and react for 3-6 hours; 4) Take the sample and let it stand to observe whether there is phase separation; 5) After phase separation, tetramethylammonium hydroxide catalyst is added and the reaction is continued at 115-120°C; 6) Raise the temperature to 140-150°C and react for 2-3 hours; 7) Cooling to below 60°C and adding photocatalyst; 8) After high-speed stirring, discharge the material; 9) Sunlight exposure.
2. According to claim 1, a photocatalyst is used in the preparation of epoxy silicone oil, wherein in step 1), the D4 reacts with tetramethylammonium hydroxide to prepare a polydimethylsiloxane cationic initiator.
3. According to the use of a photocatalyst in the preparation of epoxy silicone oil according to claim 1, in step 2), the addition of D4 and epoxy double head is for the polydimethylsiloxane cationic initiator to carry out chain growth reaction and polydimethylsiloxane chain termination reaction.
4. According to the use of a photocatalyst in the preparation of epoxy silicone oil according to claim 1, in step 5), tetramethylammonium hydroxide catalyst is added to induce the reaction between unreacted D4 and epoxy double head to increase the conversion rate of D4.
5. Use of a photocatalyst in the preparation of epoxy silicone oil according to claim 1, wherein in step 6), the reaction is carried out at 140-150°C to thermally decompose the tetramethylammonium hydroxide catalyst.
6. Use of a photocatalyst in the preparation of epoxy silicone oil according to claim 1, wherein in step 7), the photocatalyst is chloroplatinic acid.
7. The use of a photocatalyst in the preparation of epoxy silicone oil according to claim 1, wherein in step 9), the sunlight irradiation is used to photodecompose byproducts produced during the preparation of epoxy silicone oil, and the color of the epoxy silicone oil product changes from brown to colorless.