阅读说明：本技术 连续化制备二芳基六氟丙烷的方法 (Method for continuously preparing diaryl hexafluoropropane ) 是由 王汉利 王磊 刘添 单书峰 于 2020-11-30 设计创作，主要内容包括：本发明涉及一种连续化制备二芳基六氟丙烷的方法,属于有机合成技术领域。本发明所述的连续化制备二芳基六氟丙烷的方法,包括以下步骤：(1)将六氟丙酮三水合物、芳基化合物和催化剂离子液体(也可以做溶剂)混合,同时加入抗氧化剂；(2)在一定的反应温度条件下,通入循环回路反应器,并维持一定的时间,制得目标产物粗品；(3)将粗品静止降温后过滤掉固体,经精制得到纯品,将离子液体应用于下次反应。本发明科学合理,操作简单便捷,降低了对设备的腐蚀,在保持较高的转化率及选择性的前提下,提高了效率,同时增强了反应的安全性,节能环保。(The invention relates to a method for continuously preparing diaryl hexafluoropropane, and belongs to the technical field of organic synthesis. The method for continuously preparing diaryl hexafluoropropane comprises the following steps: (1) mixing hexafluoroacetone trihydrate, an aryl compound and a catalyst ionic liquid (which can also be used as a solvent), and adding an antioxidant; (2) introducing the crude product into a circulating loop reactor under a certain reaction temperature condition, and maintaining for a certain time to prepare a target product crude product; (3) and (3) cooling the crude product statically, filtering out solids, refining to obtain a pure product, and applying the ionic liquid to the next reaction. The method is scientific and reasonable, is simple and convenient to operate, reduces the corrosion to equipment, improves the efficiency on the premise of keeping higher conversion rate and selectivity, enhances the safety of the reaction, and is energy-saving and environment-friendly.)

1. A method for continuously preparing diaryl hexafluoropropane is characterized in that: the method comprises the following steps:

(1) mixing hexafluoroacetone trihydrate, an aryl compound and a catalyst ionic liquid, and adding an antioxidant;

(2) introducing the crude product into a circulating loop reactor under a certain reaction temperature condition, and maintaining for a certain time to prepare a target product crude product;

(3) and (3) cooling the crude product statically, filtering out solids, refining to obtain a pure product, and applying the ionic liquid to the next reaction.

2. The continuous process for preparing diarylhexafluoropropanes according to claim 1, wherein: the molar ratio of the hexafluoroacetone trihydrate to the aryl compound is 1: 1.5-3.

3. The continuous process for preparing diarylhexafluoropropanes according to claim 1, wherein: the mass ratio of the catalyst ionic liquid to the hexafluoroacetone trihydrate is 1-3: 1.

4. the continuous process for the preparation of diarylhexafluoropropanes according to claim 1 or 3, wherein: the catalyst ionic liquid is imidazole [ C ]_nmim][x](X＝HSO₄，H₂PO₄Etc.) or quaternary ammonium salts [ R₃NH][x](X＝HSO₄，H₂PO₄) An ionic liquid.

5. The continuous process for preparing diarylhexafluoropropanes according to claim 1, wherein: the antioxidant is sodium sulfite or sodium phosphite.

6. The continuous process for preparing diarylhexafluoropropanes according to claim 1, wherein: the antioxidant is used in an amount of 0.5-5% by mass based on the mass of the aromatic compound.

7. The continuous process for preparing diarylhexafluoropropanes according to claim 1, wherein: in the step (2), the reaction temperature is 80-150 ℃, and the reaction lasts for 5-10 min.

Technical Field

The invention relates to a method for continuously preparing diaryl hexafluoropropane, and belongs to the technical field of organic synthesis.

Background

Diarylhexafluoropropanes refer to 2, 2-diarylhexafluoropropane compounds, a class of molecules of significant value. Such as bisphenol AF, is a vulcanizing agent required by mixing fluororubber and an important intermediate material, and can be used as an intermediate for modifying polymers; 2, 2-bis (3, 4-dimethylphenyl) hexafluoropropane (6 FXY for short) is an important precursor for synthesizing a polyimide monomer 6 FDA.

The synthesis process of diaryl hexafluoropropane is basically open, and the following methods are mainly used at present:

patents US4,400,546 and CN101870641 both report that hexafluoroacetone and phenol are used to prepare bisphenol AF under the catalysis of hydrogen fluoride, the process is simple, the conditions are mature, but toxic gas hexafluoroacetone is used, and the use of hydrogen fluoride puts higher requirements on equipment; [ Journal of Fluorine Chemistry 123(2003) 221-.

Patent CN200810243703.1 reports that hexafluoroacetone trihydrate is used as a raw material, hexafluoroacetone trihydrate and aniline are used as raw materials, and four-step reactions of condensation diazotization, hydrolysis and alkylation are performed to synthesize bisphenol AF under normal pressure.

In patent CN104496763, under the action of hydrogen fluoride, hexafluoropropylene oxide and phenol are used to prepare bisphenol AF by a one-pot method, the use of HFA with high toxicity is avoided, the process is simple, but hydrogen fluoride has high corrosivity and high requirement on equipment; CN 101851147A adopts a similar method to prepare a diaryl hexafluoropropane compound.

Patent US57633699 reports the preparation of bisphenol AF by reacting phenol with anhydrous hexafluoroacetone using trifluoromethanesulfonic acid as catalyst, avoiding the use of HF, but still using HFA with high toxicity as raw material.

Patent CN 111233632 reports that hexafluoropropylene oxide and phenylalkyl ether are used as raw materials, and three processes of isomerization, friedel-crafts alkylation and removal of alkyl in ether bond are completed through one-step reaction, and continuous high-yield preparation is realized, but fluorine-containing hydrogen chloride adopted in the reaction still has strong corrosivity.

The method for preparing bisphenol AF by fluorination by taking bisphenol A as a raw material has high yield and low price, and is a very promising method, but the method uses high-toxicity F2 and has high danger, and specific reaction parameters are not reported.

Although the methods have various characteristics, and a plurality of methods and processes are very stable and mature, the problems of strong corrosivity, serious environmental pollution, greater risk in the production process and the like generally exist, so that the improvement of the existing process to realize safe and efficient production is still very meaningful.

Disclosure of Invention

The invention aims to provide a method for continuously preparing diaryl hexafluoropropane, which is scientific and reasonable, is simple and convenient to operate, reduces the corrosion to equipment, improves the efficiency on the premise of keeping higher conversion rate and selectivity, enhances the safety of reaction, saves energy and protects environment.

The chemical general formula of the diaryl hexafluoropropane is as follows:

R1＝H,Me,Et，OH；

R2＝H,Me,Et,OH。

the method for continuously preparing diaryl hexafluoropropane comprises the following steps:

(1) mixing hexafluoroacetone trihydrate, an aryl compound and a catalyst ionic liquid (which can also be used as a solvent), and adding an antioxidant;

(2) introducing the crude product into a circulating loop reactor at a certain speed under a certain reaction temperature condition, and maintaining for a certain time to prepare a target product crude product;

(3) and (3) cooling the crude product statically, filtering out solids, refining to obtain a pure product, and applying the ionic liquid to the next reaction.

Preferably, the molar ratio of hexafluoroacetone trihydrate to aryl compound is 1: 1.5-3.

Preferably, the mass ratio of the catalyst ionic liquid to the hexafluoroacetone trihydrate is 1-3: 1.

preferably, the catalyst ionic liquid is imidazole [ C ]_nmim][x](X＝HSO₄，H₂PO₄Etc.) or quaternary ammonium salts [ R₃NH][x](X＝HSO₄，H₂PO₄) An ionic liquid.

Preferably, the antioxidant is sodium sulfite or sodium phosphite.

Preferably, the antioxidant is used in an amount of 0.5 to 5% by mass based on the amount of the aromatic compound.

Preferably, in the step (2), the reaction temperature is 80-150 ℃, preferably 90-120 ℃; preferably, the reaction is carried out for 5-10 min.

The feeding speed is determined by the reaction retention time and the size of the equipment, and the feeding speed can be obtained according to the size of the reaction equipment under the condition of the precursor determined by the reaction retention time.

The ionic liquid recovered by the method is recycled after vacuum drying, and the catalytic activity is not obviously reduced after 5 times of recycling.

The invention adopts the reusable ionic liquid catalyst and the hexafluoroacetone trihydrate with higher safety as raw materials, thereby reducing the corrosion to equipment, improving the safety of the reaction and reducing the generation of three wastes; the circulation loop reactor is used as a reaction device, so that the mass transfer and heat transfer of the reaction are enhanced, the continuous production of the product is realized, and the preparation efficiency is improved.

The loop reactor according to the invention is a device known to the person skilled in the art.

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

(1) the efficiency is improved by adopting a continuous production mode on the premise of keeping higher conversion rate and selectivity;

(2) the ionic liquid catalyst is used, is nontoxic, can be repeatedly used for many times, and is environment-friendly;

(3) the use of substances with higher toxicity and strong corrosivity is avoided, and the safety of the reaction is improved;

(4) and a strong acid substance is not used, so that the generation of waste acid is avoided, and the environmental protection pressure is reduced.

Detailed Description

The present invention is further illustrated by the following examples, which are not intended to limit the practice of the invention.

Example 1

500g of hexafluoroacetone trihydrate, 500g of [ C ]₆mim][HSO₄]481g of o-xylene and 5g of sodium sulfite are stirred and mixed at room temperature, and then pumped into a circulating loop reactor for reaction, the reaction temperature is 120 ℃, the reaction retention time is 8min, after the reaction is finished, the reaction is kept stand, a solid product is separated out from a reaction solution, a crude product is obtained by filtration and separation, the reaction conversion rate is 98 percent calculated by hexafluoroacetone trihydrate, the selectivity is 93 percent, and a pure product is obtained by recrystallization.

Example 2

500g of hexafluoroacetone trihydrate, 500g of [ C ]₆mim][HSO₄]433g of o-xylene and 5g of sodium sulfite are stirred and mixed at room temperature, and then pumped into a circulation loop reactor for reaction, the reaction temperature is 130 ℃, the reaction retention time is 10min, after the reaction is finished, the reaction is kept still, a solid product is separated out from a reaction solution, a crude product is obtained by filtration and separation, the reaction conversion rate is 99% by weight of hexafluoroacetone trihydrate, the selectivity is 89%, and a pure product is obtained by recrystallization.

Example 3

500g of hexafluoroacetone trihydrate, 500g of [ Et ]₃N][HSO₄]530g of o-xylene and 5g of sodium sulfite are stirred and mixed at room temperature, and then pumped into a circulation loop reactor for reaction, the reaction temperature is 90 ℃, the reaction retention time is 8min, after the reaction is finished, the reaction is kept stand, a solid product is separated out from a reaction solution, a crude product is obtained by filtration and separation, the reaction conversion rate is 90% by weight of hexafluoroacetone trihydrate, the selectivity is 94%, and a pure product is obtained by recrystallization.

Example 4

Will 500g hexafluoroacetone trihydrate, 500g [ C ]₆mim][HSO₄]448g of phenol and 10g of sodium sulfite are stirred and mixed at room temperature, and then are pumped into a circulating loop reactor for reaction, the reaction temperature is 100 ℃, the reaction retention time is 5min, after the reaction is finished, the reaction is kept stand, a solid product is separated out from a reaction solution, a crude product is obtained by filtration and separation, the reaction conversion rate is 98 percent by taking hexafluoroacetone trihydrate, the selectivity is 95 percent, and a pure product is obtained by recrystallization.

Example 5

500g of hexafluoroacetone trihydrate, 500g of [ Et ]₃N][HSO₄]493g of phenol and 10g of sodium sulfite are stirred and mixed at room temperature, then the mixture is pumped into a circulating loop reactor for reaction, the reaction temperature is 100 ℃, the reaction retention time is 6min, after the reaction is finished, the mixture is stood, a solid product is separated out from a reaction liquid, a crude product is obtained by filtration and separation, the reaction conversion rate is 99 percent calculated by hexafluoroacetone trihydrate, the selectivity is 96 percent, and a pure product is obtained by recrystallization.

Example 6

500g of hexafluoroacetone trihydrate, 500g of [ C ]₆mim]HSO₄403g of phenol and 6g of sodium sulfite are stirred and mixed at room temperature, and then pumped into a circulation loop reactor for reaction, the reaction temperature is 90 ℃, the reaction retention time is 8min, after the reaction is finished, the reaction is kept stand, a solid product is separated out from a reaction solution, a crude product is obtained by filtration and separation, the reaction conversion rate is 97 percent based on hexafluoroacetone trihydrate, the selectivity is 82 percent, and a pure product is obtained by recrystallization.

Example 7

500g of hexafluoroacetone trihydrate, 500g of [ C ]₆mim][HSO₄](fifth circulation), 448g of phenol and 10g of sodium sulfite are stirred and mixed at room temperature, and then are pumped into a circulation loop reactor for reaction, the reaction temperature is 100 ℃, the reaction retention time is 5min, after the reaction is finished, the reaction is kept still, a solid product is separated out from the reaction liquid, a crude product is obtained by filtration and separation, the reaction conversion rate is 95% by weight of hexafluoroacetone trihydrate, the selectivity is 93%, and a pure product is obtained by recrystallization.

Comparative example 1

377g of hexafluoroacetone (gas), 448g of phenol and 363g of hydrogen fluoride are added into a reaction kettle, the reaction temperature is 100 ℃, the pressure is 1.0MPa, the reaction is carried out for 8 hours, after the reaction is finished, the reaction conversion rate is 89% in terms of hexafluoroacetone, the selectivity is 89%, and the pure product is obtained after the crude product is subjected to alkali washing and recrystallization.

Comparative example 2

377g of hexafluoroacetone (gas), 363g of hydrogen fluoride and 505g of o-xylene are added into a reaction kettle, the reaction temperature is 150 ℃, the pressure is 2.5MPa, the reaction is carried out for 12 hours, after the reaction is finished, the reaction conversion rate is 90 percent in terms of hexafluoroacetone, the selectivity is 87 percent, and the crude product is recrystallized to obtain a pure product.

The above-mentioned embodiments are intended to illustrate the technical solutions and advantages of the present invention, and it should be understood that the above-mentioned embodiments are only specific embodiments of the present invention, and are not intended to limit the present invention, and any modifications, additions, equivalents, etc. made within the scope of the principles of the present invention should be included in the scope of the present invention.