阅读说明：本技术 一种分步格氏法中四氢呋喃的回收处理工艺 (Recovery processing technology of tetrahydrofuran in step-by-step Grignard method ) 是由 霍晓剑 常贺飞 毛满意 邓国伟 罗念 白雪琴 常思乔 武卫华 熊丽霞 任家君 黄 于 2020-07-20 设计创作，主要内容包括：本发明公开一种分步格氏法中四氢呋喃的回收处理工艺,包括有机碱处理、过滤、调整溶液配比和脱水干燥；有机碱处理的步骤具体包括：向含四氢呋喃的回收液中加入有机碱,随后升温至35～45℃,保温搅拌0.5～2h,得到有机碱处理后的含四氢呋喃溶液；调整溶液配比的步骤具体包括：向过滤后的含四氢呋喃溶液中加入改性溶剂,得到调整溶液配比后的含四氢呋喃溶液。本发明处理后得到的含四氢呋喃混合物能够直接套用至分步格氏试剂法生产甲基苯基二甲氧基硅烷的过程中,且对目标产物收率影响较小；本发明只需常压简单分溜回收混合物,避免反复精馏回收四氢呋喃造成的高能耗和安全风险、回收成本低。(The invention discloses a tetrahydrofuran recovery processing technology in a step-by-step Grignard method, which comprises organic base treatment, filtration, solution proportioning adjustment, dehydration and drying; the organic base treatment step specifically comprises: adding organic base into the tetrahydrofuran-containing recovery liquid, then heating to 35-45 ℃, and stirring for 0.5-2 hours under heat preservation to obtain a tetrahydrofuran-containing solution after organic base treatment; the step of adjusting the solution ratio specifically comprises: and adding a modified solvent into the filtered tetrahydrofuran-containing solution to obtain the tetrahydrofuran-containing solution with the solution ratio adjusted. The tetrahydrofuran-containing mixture obtained after treatment can be directly applied to the process of producing the methyl phenyl dimethoxy silane by the step-by-step Grignard reagent method, and has small influence on the yield of a target product; the invention only needs to simply separate and recycle the mixture under normal pressure, thereby avoiding high energy consumption and safety risk caused by recycling tetrahydrofuran by repeated rectification and having low recycling cost.)

1. A recovery processing technology of tetrahydrofuran in a step Grignard method is characterized by comprising organic base treatment, filtration, solution ratio adjustment, dehydration and drying; wherein the content of the first and second substances,

the organic base treatment step specifically comprises: adding organic base into the tetrahydrofuran-containing recovery liquid, then heating to 35-45 ℃, and stirring for 0.5-2 hours under heat preservation to obtain a tetrahydrofuran-containing solution after organic base treatment;

the step of adjusting the solution ratio specifically comprises: and adding a modified solvent into the filtered tetrahydrofuran-containing solution to obtain the tetrahydrofuran-containing solution with the solution ratio adjusted.

2. The process for recycling tetrahydrofuran in the stepwise grignard process according to claim 1, wherein the recycling solution containing tetrahydrofuran is a mixed solution containing tetrahydrofuran obtained by simple fractional distillation at atmospheric pressure of 100 ℃ or lower in the process of producing the methylphenyldimethoxysilane by the stepwise grignard reagent method.

3. The process for recycling tetrahydrofuran in the stepwise grignard process according to claim 2, wherein the recycling solution containing tetrahydrofuran comprises: 80-95% of tetrahydrofuran, 0-6% of petroleum ether component, 1-15% of methyltrimethoxy silane and 0.01-10% of chlorobenzene and other silane components.

4. The stepwise grignard process according to claim 1, wherein the organic base is sodium methoxide, and the amount of the organic base added is 0.01% to 0.4% of the recovery solution containing tetrahydrofuran.

5. The stepwise grignard process tetrahydrofuran recycling process according to claim 1, wherein the modified solvent is one or both of fresh tetrahydrofuran and fresh petroleum ether.

6. The process for recycling tetrahydrofuran in the stepwise Grignard process according to claim 5, wherein the tetrahydrofuran content in the fresh tetrahydrofuran is not less than 99.5% and the water content is not more than 100 ppm; the boiling range of the fresh petroleum ether is 90-120 ℃, and the water content is less than or equal to 100 ppm.

7. The process of claim 1, wherein the solution containing tetrahydrofuran is prepared by the following steps: 80-90% of tetrahydrofuran, 3-13% of petroleum ether and less than or equal to 7% of other components.

8. The process for recovery and treatment of tetrahydrofuran in a stepwise grignard process according to claim 1, wherein the step of filtering comprises: and cooling the tetrahydrofuran solution treated by the organic base to room temperature, and filtering to obtain a filtered tetrahydrofuran solution.

9. The process for recovery and treatment of tetrahydrofuran in stepwise grignard as claimed in claim 1, wherein the step of dehydration and drying comprises: and dehydrating and drying the tetrahydrofuran-containing solution with the ratio of the solution adjusted by using a 3A molecular sieve until the water content is less than or equal to 100ppm to obtain the dehydrated and dried tetrahydrofuran-containing solution.

Technical Field

The invention relates to the technical field of organic chemical synthesis, in particular to a tetrahydrofuran recovery processing technology in a step-by-step Grignard method.

Background

The methyl phenyl dimethoxy silane is an important organic silicon monomer, can endow organic silicon materials with more excellent performances such as high and low temperature resistance, electrical insulation grade, radiation resistance and the like, and is commonly used for preparing methyl phenyl silicone oil, silicone rubber, silicone resin and the like.

The grignard reagent method is a relatively mature synthesis method of the methyl phenyl dimethoxy silane, and is generally divided into a step method and a one-step method. The fractional step method is that chlorobenzene or bromobenzene and magnesium metal are first made into Grignard reagent through Grignard reaction, and the Grignard reagent and methyltrimethoxysilane are then synthesized into the target product methyl phenyl dimethoxy silane through substitution reaction. Among them, bromobenzene has high Grignard reaction activity but high price, and chlorobenzene is not easy to have Grignard reaction and needs a large amount of tetrahydrofuran or diethyl ether solvent. In the synthesis technology for synthesizing the methylphenyldimethoxysilane by the Grignard method reported in the literature, bromobenzene is mostly adopted for synthesis. The 'one-step method' is that chlorobenzene or bromobenzene, magnesium metal and methyltrimethoxysilane are subjected to Grignard reaction and substitution reaction simultaneously in a reactor to obtain a target product. Due to the particular grignard reactivity of chlorobenzene, the yield of the "one-shot" reaction using chlorobenzene is generally not high.

The stepwise Grignard method for synthesizing the methyl phenyl dimethoxysilane by using chlorobenzene as a raw material generally comprises the steps of adding metal magnesium, chlorobenzene, tetrahydrofuran and an initiator into a reactor under the protection of nitrogen for initiation, dropwise adding a mixture of the chlorobenzene and the tetrahydrofuran after stabilization to prepare a Grignard reagent, adding the prepared Grignard reagent into the reactor with the methyl trimethoxysilane under the protection of nitrogen for substitution reaction to obtain a target product crude product, and then filtering, distilling to remove a solvent and rectifying to obtain the methyl phenyl dimethoxysilane product. The specific reaction equation of the stepwise grignard reaction is as follows:

PhCl+Mg→PhMgCl

PhMgCl+MeSi(OMe)₃→MePhSi(OMe)₂+MeOMgCl

in the process, a large amount of pure tetrahydrofuran is used as a reaction solvent to improve the conversion rate of the Grignard reaction step. However, tetrahydrofuran and methyltrimethoxysilane are difficult to separate due to azeotropic characteristics, and if excessive methyltrimethoxysilane and other chlorosilane impurities are contained in the recovered tetrahydrofuran, the yield is affected by direct application. At present, the purity of tetrahydrofuran is generally improved by rectification and then drying through a molecular sieve, but the recovery cost is high, the energy consumption is high, and the safety is poor.

Disclosure of Invention

The invention aims to overcome the technical defects, provides a recovery treatment process of tetrahydrofuran in a step-by-step Grignard method, and solves the technical problems of high recovery cost, high energy consumption and poor safety in the prior art.

In order to achieve the technical purpose, the invention provides a tetrahydrofuran recovery processing technology in a step-by-step Grignard method, which comprises organic base treatment, filtration, solution proportion adjustment, dehydration and drying; the organic base treatment step specifically comprises: adding organic base into the tetrahydrofuran-containing recovery liquid, then heating to 35-45 ℃, and stirring for 0.5-2 hours under heat preservation to obtain a tetrahydrofuran-containing solution after organic base treatment; the step of adjusting the solution ratio specifically comprises: and adding a modified solvent into the filtered tetrahydrofuran-containing solution to obtain the tetrahydrofuran-containing solution with the solution ratio adjusted.

Compared with the prior art, the invention has the beneficial effects that:

according to the invention, the tetrahydrofuran-containing recovery liquid is subjected to impurity removal by using an organic base, and then is blended by using tetrahydrofuran and petroleum ether, so that the tetrahydrofuran-containing mixture obtained after treatment can be directly applied to the process of producing the methyl phenyl dimethoxysilane by the step-by-step Grignard reagent method, and the influence on the yield of a target product is small; meanwhile, due to the existence of petroleum ether, the contents of methyltrimethoxysilane and other impurity chlorosilane in the fraction with the normal pressure fractionation temperature of less than or equal to 100 ℃ are lower, the utilization efficiency of the recovered solvent is further improved, and the difficulty in recovery and reuse is reduced; the invention only needs to simply separate and recycle the mixture under normal pressure, thereby avoiding high energy consumption and safety risk caused by recycling tetrahydrofuran by repeated rectification and having low recycling cost.

Drawings

FIG. 1 is a process flow diagram of an embodiment of the recovery process of tetrahydrofuran in the stepwise Grignard process according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 1, the present invention provides a process for recovering tetrahydrofuran in a stepwise grignard process, comprising S1 organic base treatment, S2 filtration, S3 solution proportioning adjustment, and S4 dehydration drying. Each process is described in detail below.

The step of organic base treatment of S1 specifically includes: adding organic base into the tetrahydrofuran-containing recovery liquid, then heating to 35-45 ℃, and stirring for 0.5-2 hours under heat preservation to obtain the tetrahydrofuran-containing solution after organic base treatment. In the process, the recovered liquid containing tetrahydrofuran is treated by using the organic alkali, so that chlorosilane impurities in the recovered liquid containing tetrahydrofuran can be removed conveniently, and the problem that the yield is reduced due to deactivation of Grignard reaction caused by the chlorosilane impurities in the subsequent application process is avoided. In this embodiment, the tetrahydrofuran-containing recovered solution is a tetrahydrofuran-containing mixed solution obtained by simple fractionation at normal pressure at a temperature of 100 ℃ or lower in the process of producing methylphenyldimethoxysilane by a stepwise grignard reagent method, and comprises the following components: 80-95% of tetrahydrofuran, 0-6% of petroleum ether component, 1-15% of methyltrimethoxy silane and 0.01-10% of chlorobenzene and other silane components. Specifically, the recovery liquid containing tetrahydrofuran recovered in the process of producing the methyl phenyl dimethoxy silane by using fresh tetrahydrofuran as a raw material comprises the following components: 80 to 90 percent of tetrahydrofuran, 10 to 15 percent of methyltrimethoxysilane, 0.01 to 10 percent of chlorobenzene and other silane components; after repeated application, the obtained tetrahydrofuran-containing recovery liquid also contains a certain amount of petroleum ether with a boiling range of 90-120 ℃, and the applied tetrahydrofuran-containing recovery liquid comprises the following components: 82 to 93 percent of tetrahydrofuran, 4 to 6 percent of petroleum ether component, 1 to 4 percent of methyl trimethoxy silane, and 0.01 to 8 percent of chlorobenzene and other silane components. Wherein, the other silane components comprise a certain amount of chlorosilane. In the present embodiment, the organic base is sodium methoxide, and the amount of the organic base added is 0.01% to 0.4%, preferably 0.1% to 0.4%, and more preferably 0.3% to 0.4% of the mixed solution containing tetrahydrofuran. In the process, the addition amount of the organic base needs to be strictly controlled, the removal effect of impurities such as chlorosilane is poor due to the fact that the addition amount is too small, the residue of the organic base in the tetrahydrofuran-containing solution after the organic base treatment is more due to the fact that the addition amount is too large, chlorobenzene is consumed in the subsequent reaction, and the yield is affected.

The S2 filtering step specifically comprises the following steps: and cooling the tetrahydrofuran-containing solution treated by the organic base to room temperature, and filtering to obtain a filtered tetrahydrofuran-containing solution. The solid impurities in the tetrahydrofuran-containing solution after the organic alkali treatment can be removed by filtration. In this embodiment, the composition of the filtered tetrahydrofuran-containing solution is: 80-95% of tetrahydrofuran, 0-6% of petroleum ether component, 1-15% of methyltrimethoxy silane and 0.01-4% of chlorobenzene and other silane components. Specifically, when the production raw material is fresh tetrahydrofuran, the filtered tetrahydrofuran-containing solution comprises the following components: 80 to 90 percent of tetrahydrofuran, 10 to 15 percent of methyltrimethoxysilane, 0.01 to 4 percent of chlorobenzene and other silane components; when the production raw material is tetrahydrofuran which is recycled after repeated use, the obtained tetrahydrofuran-containing recycling liquid comprises the following components: 82 to 93 percent of tetrahydrofuran, 4 to 6 percent of petroleum ether component, 1 to 4 percent of methyl trimethoxy silane, and 0.01 to 4 percent of chlorobenzene and other silane components.

The step of S3 of adjusting the solution ratio specifically comprises: and adding a modified solvent into the filtered tetrahydrofuran-containing solution to obtain the tetrahydrofuran-containing solution with the solution ratio adjusted. In this embodiment, the composition of the tetrahydrofuran-containing solution after the solution ratio is adjusted is as follows: 80-90% of tetrahydrofuran, 3-13% of petroleum ether and less than or equal to 7% of other components. Preferably, the composition of the tetrahydrofuran solution after the mixture ratio of the obtained solution is adjusted is as follows: 84 to 87.5 percent of tetrahydrofuran, 7.5 to 11 percent of petroleum ether and less than or equal to 5 percent of other components. According to the invention, the azeotropic characteristic of tetrahydrofuran and methyltrimethoxysilane can be changed by adding petroleum ether into the filtered tetrahydrofuran-containing solution, so that the content of methyltrimethoxysilane and other impurity chlorosilane in the tetrahydrofuran can be greatly reduced by only atmospheric fractionation in the recovery process of the subsequent mechanical reaction of the recovered tetrahydrofuran treated by the process, and the content of the fraction of less than or equal to 100 ℃ in the recovered tetrahydrofuran can be greatly reduced, thereby improving the reaction effect of the recovered solvent in the Grignard reaction step; meanwhile, the composition of the tetrahydrofuran-containing solution after the solution ratio is adjusted is controlled within the range, so that the tetrahydrofuran-containing solution after the solution ratio is adjusted is dehydrated and then is directly applied to the Grignard reaction step of the methyl phenyl dimethoxy silane as a raw material, and the influence on the yield of the product is little. It should be noted that if the content of the petroleum ether component is too high, the product yield in the process of applying mechanically will be low; if the content of the petroleum ether component is too low, the azeotropic property of the tetrahydrofuran and the methyltrimethoxysilane is not favorably improved, and the recovered tetrahydrofuran has too high content of the methyltrimethoxysilane and great rectification difficulty. Specifically, the above-mentioned other components include unreacted chlorobenzene, methyltrimethoxysilane, various chlorosilanes, alkylsiloxane impurities, and the like. In the present embodiment, the modifying solvent is one or both of tetrahydrofuran and petroleum ether. In the process, the used tetrahydrofuran and petroleum ether are directly available and have not undergone the Grignard reaction (for the convenience of distinction, the tetrahydrofuran and the petroleum ether are respectively called as fresh tetrahydrofuran and fresh petroleum ether). Specifically, the tetrahydrofuran content in the fresh tetrahydrofuran used in the step of adjusting the solution ratio is more than or equal to 99.5 percent, and the water content is less than or equal to 100 ppm; the boiling range of the fresh petroleum ether is 90-120 ℃, and the water content is less than or equal to 100 ppm.

The step of S4 dehydration drying specifically comprises the following steps: and (3) dehydrating and drying the tetrahydrofuran-containing solution with the solution ratio adjusted by using a 3A molecular sieve until the water content is less than or equal to 100ppm to obtain the dehydrated and dried tetrahydrofuran-containing solution. In the process, the obtained dehydrated and dried tetrahydrofuran-containing solution can be directly used as a mixed raw material solvent used in the Grignard reaction step for producing the methyl phenyl dimethoxy silane by a step-by-step Grignard reagent method.