CN1127754A - Process for producing ethyl ortho-silicate from silane coupler leftover - Google Patents
Process for producing ethyl ortho-silicate from silane coupler leftover Download PDFInfo
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- CN1127754A CN1127754A CN 95112029 CN95112029A CN1127754A CN 1127754 A CN1127754 A CN 1127754A CN 95112029 CN95112029 CN 95112029 CN 95112029 A CN95112029 A CN 95112029A CN 1127754 A CN1127754 A CN 1127754A
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Abstract
The process for preparing ethyl ortho-silicate with the fraction before addition in production of silane coupler KH-550 includes mixing said fraction before addition with alcohol to make the SiCl4 in the fraction and alcohol take part in reaction to produce ethyl ortho-silicate and hydrogen chloride, removing impurities, e.g. chloropropenes and hydrogen chloride, by carry-over of alcohol during heating, and filtering decolouring.
Description
The present invention belongs to a production method of acyclic compound, in particular, it relates to a method for producing ethyl orthosilicate by utilizing addition front-cut fraction in the production of KH-550 silane coupling agent.
At present, the industrial silicon, chlorine and ethanol are used as raw materials to produce the ethyl orthosilicate in batches, and the production process comprises four steps of preparing silicon tetrachloride, mixing and reacting, removing impurities and filtering and decoloring. The preparation of the silicon tetrachloride is that industrial silicon reacts with chlorine to generate the silicon tetrachloride at the temperature of 600 ℃. The mixing reaction is that the silicon tetrachloride and the ethanol react in a certain proportion to generate the ethyl orthosilicate and the hydrogen chloride. The impurities are removed by removing the chlorine oxide in the reactants by an extraction method. Filtering and decoloring by using a filtering tank decoloring agent to ensure that the product reaches the quality standard. KH-550 silane coupling agent has been produced for many years, but the front-end distillate in the production process is silicon tetrachloride which is taken as a main body and contains chloropropene and chlorosilane impurities, so that the silicon tetrachloride is difficult to purify and is not utilized all the time, and the silicon tetrachloride is dumped as waste, thereby not only causing environmental pollution, but also wasting raw materials.
The invention aims to provide a method for producing tetraethoxysilane, which can reduce pollution, takes the added front fraction of a silane coupling agent as a raw material for reproduction, and creates higher economic benefit.
The invention is realized by the process comprising three steps of mixing reaction, impurity removal and filtering decoloration.
Mixing and reacting, namely directly producing by taking an addition front cut fraction in the production of the KH-550 silane coupling agent as a raw material, feeding the raw material in a mixing reactor and a reaction kettle in a weight ratio of the addition front cut fraction to ethanol of 1: 0.7-1.0, and reacting silicon tetrachloride in the addition front cut fraction with the ethanol to generate ethyl orthosilicate and chlorine chloride, wherein the reaction formula is as follows:
the impurities are removed by removing chloropropene low-boiling point impurities and hydrogen chloride generated by the reaction in the addition front fraction. The method of heating and removing carried by ethanol, namely the method of adding ethanol and heating under reduced pressure, is adopted, because the boiling point of chloropropene impurities is low, the chloropropene impurities are removed along with hydrogen chloride, chlorine chloride is absorbed by water to generate hydrochloric acid, and other impurities are discharged along with tail gas.
Chlorosilane impurities in the addition front-end fraction generate corresponding ethoxysilane in the reaction, and the ethoxysilane exists in the product, so that the product performance can be improved.
The filtering decolorization is the same as the prior art.
The indexes of the product produced by the method are as follows:
relative density: 0.95 to 1.00
SiO2The content is as follows: 32 to 34 percent
Acidity: less than or equal to 0.04 percent
Viscosity: less than or equal to 1.6
Low fraction: less than or equal to 2 percent
The present invention also can adopt the method that the distillate before the addition is distilled or rectified to take certain distillate as the raw material of the mixing reaction to produce the ethyl orthosilicate. And in the distillation, adding the addition front cut fraction into a distillation kettle, heating, distilling in a rectifying tower, stopping distilling when the temperature in the kettle reaches 59-61 ℃ and the temperature at the top of the tower reaches 56 ℃, removing low-boiling-point impurities in the front cut fraction, retaining the chlorsilane-type impurities in the product, and guiding the product in the distillation kettle out to serve as the raw material of the mixing reaction. And the rectification is to add the addition front fraction into a distillation kettle to heat, refine in a rectification tower with 20-40 theoretical plate numbers, and collect the fraction with the tower top temperature of 56 +/-1 ℃ as the raw material of the mixed reaction.
The invention has the advantages of simple process and easy implementation. The addition front distillate is a strong acid substance which seriously pollutes the environment, and is dumped as waste, so that the environment is polluted and waste is caused. The method makes use of waste, the produced tetraethoxysilane is a chemical product with high price, and the by-product hydrochloric acid is also a popular product with large demand on the market. Overcomes the difficulty of removing various impurities from the raw material refining and adding front-end distillate in the prior art, retains few impurities and improves the performance of the product. Can treat pollution, increase income and create profits.
The present invention will be described in detail below with reference to the accompanying drawings and examples.
The figure is a process flow chart of the invention
1-addition front-end distillate tank 2-ethanol tank 3-ethanol recovery tank 4-rotameter 5-mixing reactor 6-reaction kettle 7-thermometer 8-vacuum meter 9-glass tube 10-enamel cooler 11-vapor-liquid separator 12-chlorine chloride discharge pipe 13-ethyl orthosilicate tank 14-filter tank 15-packaging barrel
And the mixing reaction is to add 100 kg of addition front distillate into an addition front distillate tank (1), to ensure that the total ethanol amount of a recovered ethanol tank (3) and an ethanol tank (2) is 80 kg, to open the three tanks simultaneously after the charging is finished, to add the mixture into a mixing reactor (5) at a constant speed, to enter a reaction kettle (6) through an overflow port, to drip off the mixture in about 1.5 hours at a controlled speed, and to react at a temperature below 80 ℃ to generate ethyl orthosilicate and hydrogen oxide.
The impurity removal is to remove chloropropene low-boiling point impurities and chlorine chloride generated in the reaction, a method of carrying ethanol and heating for removing the impurities is adopted, after a front fraction and an ethanol gold part enter a reaction kettle (6), a feeding valve is closed, a vacuum pump is opened, the vacuum degree is controlled by a valve of a hydrogen chloride discharge pipe, when the vacuum degree in the reaction kettle reaches below-0.08 MPa, steam is introduced into an interlayer of the reaction kettle, and when the temperature in the reaction kettle is controlled to rise to 80 ℃, the steam valve and the vacuum pump are closed, so that the reaction is recovered to normal pressure. After 20 kg of ethanol is added into the reaction kettle from the feeding pipe through the mixing reactor, the feeding valve is closed, the pressure is reduced again, the temperature is raised, when the vacuum degree reaches below-0.08 MPa and the temperature is raised to 80 ℃, the steam valve and the vacuum pump are closed, and the reaction is recovered to normal pressure. And adding 20 kg of ethanol into the reaction kettle through the feed pipe through the mixing reactor, closing the feed valve, reducing the pressure and raising the temperature again, and closing the steam valve and the vacuum pump to react and recover the normal pressure when the vacuum degree reaches-0.08 MPa again and the temperature is 80 ℃. Can remove low boiling point impurities of nitrogen propylene in the distillate before addition, and simultaneously reduce the content of chlorine chloride to below 0.05 percent. The chlorine chloride is absorbed with water as hydrochloric acid. Chlorosilane impurities contained in the addition front cut fraction generate corresponding dichlorosilane in the reaction, and the dichlorosilane exists in the product.
The filtering and decoloring are implemented by filtering and decoloring silicic acid acetic acid produced from a reaction kettle by a filter tank (14), and activated carbon is used as a decoloring agent. The quality of the decolored tetraethoxysilane product reaches the following standard:
relative density: 0.97
SiO2The content is as follows: 33.2 percent
Acidity: less than or equal to 0.03 percent
Viscosity: less than or equal to 1.6
Low fraction: less than or equal to 1.5 percent
The process of impurity removal is different with the weight of the raw materials, the process of adding ethanol and reducing pressure and temperature can be repeatedly operated until the content of hydrogen chloride in the product is lower than 0.05 percent. The amount of ethanol added in each case was 1/5% of the weight of the charge in the front cut. The operating temperature is optimized below 80 ℃ otherwise side reactions increase.
Claims (6)
1. A process for preparing ethyl orthosilicate from the leftover of silane coupler includes such steps as mixing reaction, removing impurities and filtering for decolouring, and features that the addition front fraction of KH-550 silane coupler is used as raw material, or the addition front fraction is distilled or rectified to obtain a certain fraction, which is used as raw material for mixing reaction, the mixing reaction is carried out by adding ethanol in the weight ratio of 1: 0.7-1.0, reacting silicon tetroxide with ethanol in the addition front fraction to obtain ethyl orthosilicate and hydrogen chloride,
the impurities are removed by removing chloropropene low-boiling point impurities in the addition front fraction and hydrogen chloride generated in the reaction.
2. The process for producing tetraethoxysilane according to claim 1, wherein the removal of impurities is carried out by heating with ethanol, i.e., adding ethanol, and raising the temperature under reduced pressure to remove impurities, and the process is repeated until the hydrogen chloride content in the product is less than 0.05%, wherein the amount of ethanol added is 1/5 of the weight of the distillate before addition, and the operation temperature is preferably below 80 ℃.
3. The process for producing tetraethoxysilane according to claim 1, wherein the oxysilane-type impurities contained in the addition front cut produce the corresponding ethoxysilane in the reaction, which is present in the product.
4. A process for the production of tetraethoxysilane according to claim 1, characterized in that hydrogen chloride is absorbed with water to produce hydrochloric acid.
5. The method for producing tetraethoxysilane according to claim 1, wherein the raw material distillation is to add the addition front cut fraction into a distillation still to raise the temperature, when the temperature in the still reaches 59 to 61 ℃ and the temperature at the top of the still reaches 56 ℃, the distillation is stopped, low boiling point impurities in the front cut fraction are removed, chlorosilane impurities remain in the product, and the product in the distillation still is led out to be used as the raw material for the mixing reaction.
6. The method for producing tetraethoxysilane according to claim 1, wherein the raw material rectification is to add the pre-addition fraction into a distillation still for heating, and collect the fraction with the tower top temperature of 56 ± 1 ℃ as the raw material of the mixing reaction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN95112029A CN1045298C (en) | 1995-09-26 | 1995-09-26 | Process for producing ethyl ortho-silicate from silane coupler leftover |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN95112029A CN1045298C (en) | 1995-09-26 | 1995-09-26 | Process for producing ethyl ortho-silicate from silane coupler leftover |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1127754A true CN1127754A (en) | 1996-07-31 |
| CN1045298C CN1045298C (en) | 1999-09-29 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN95112029A Expired - Fee Related CN1045298C (en) | 1995-09-26 | 1995-09-26 | Process for producing ethyl ortho-silicate from silane coupler leftover |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102634028A (en) * | 2012-04-08 | 2012-08-15 | 荆州市江汉精细化工有限公司 | Method for preparing modified tetraethoxysilane by use of waste in production of 3-chloropropyltrichlorosilane |
| CN104072530A (en) * | 2014-06-24 | 2014-10-01 | 吴娟 | Device system and method for recycling chlorosilane residual slurry liquid |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5175330A (en) * | 1992-07-16 | 1992-12-29 | Dow Corning Corporation | Process for the recovery of hydrogen chloride and monomeric alkoxysilanes from mixtures of chloride-containing silicon compounds |
-
1995
- 1995-09-26 CN CN95112029A patent/CN1045298C/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102634028A (en) * | 2012-04-08 | 2012-08-15 | 荆州市江汉精细化工有限公司 | Method for preparing modified tetraethoxysilane by use of waste in production of 3-chloropropyltrichlorosilane |
| CN104072530A (en) * | 2014-06-24 | 2014-10-01 | 吴娟 | Device system and method for recycling chlorosilane residual slurry liquid |
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| Publication number | Publication date |
|---|---|
| CN1045298C (en) | 1999-09-29 |
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