CN-117105767-B - Preparation method of trifluoro propionic acid

CN117105767BCN 117105767 BCN117105767 BCN 117105767BCN-117105767-B

Abstract

The invention discloses a preparation method of trifluoropropionic acid, which comprises the following steps of reacting acetic acid with trifluoropropene under the action of a catalyst to obtain trifluoropropyl acetate, exchanging trifluoropropyl acetate with methanol to obtain trifluoropropanol, and oxidizing trifluoropropanol with hydrogen peroxide under the action of the catalyst to obtain trifluoropropionic acid. The invention has higher yield, simple process condition and cheaper raw materials, and can greatly reduce the cost of the trifluoro propionic acid.

Inventors

WU SHENGJUN
GE FANLONG
WANG BIN
CHEN CAIYAN
GUO YINGJIE

Assignees

南通宝凯药业有限公司

Dates

Publication Date: 20260505
Application Date: 20230825

Claims (1)

1. A preparation method of trifluoro propionic acid is characterized by comprising the following steps: Adding acetic acid and a certain proportion of catalyst into an autoclave, heating to a certain temperature, starting to introduce trifluoropropene, maintaining a certain reaction pressure, and after the trifluoropropene is introduced for 8-10 hours, cooling, transferring into a flask with a rectifying tower and a condenser, and rectifying under reduced pressure to obtain trifluoropropyl acetate; adding trifluoropropyl acetate and a certain equivalent of methanol into a flask, adding a certain proportion of catalyst, heating and refluxing to react until trifluoropropyl acetate is completely reacted, and then placing the mixture into a rectifying device for rectification to obtain trifluoropropanol; step three, oxidizing trifluoropropanol and hydrogen peroxide under the action of a catalyst at a fixed reaction temperature to obtain trifluoropropionic acid; In the first step, a certain proportion of catalyst is 1-10% of acetic acid by mass, the catalyst is boron trifluoride diethyl ether, the molar ratio of acetic acid to trifluoropropene is 1-3:1, a certain reaction pressure is kept at 1-3MPa, and the temperature is heated to 120-150 ℃; in the second step, the equivalent of methanol is 2-5 times of the mole equivalent, the catalyst with a certain proportion is 1-10% of the mass of methanol, and the catalyst is alkali metal salt comprising one of sodium hydroxide, potassium hydroxide, sodium methoxide, sodium ethoxide, sodium tert-butoxide and potassium tert-butoxide; In the third step, the molar ratio of the trifluoropropanol to the hydrogen peroxide is 1:1.05-1.5, the concentration of the hydrogen peroxide is 8-27.5%, the catalyst is ferric chloride and hydrochloric acid, the amount of the ferric chloride is 0.2-1% of the mass of the hydrogen peroxide, the amount of the hydrochloric acid is 2-5% of the mass of the hydrogen peroxide, and the fixed reaction temperature is 60-100 ℃.

Description

Preparation method of trifluoro propionic acid Technical Field The invention belongs to the technical field of organofluorine industry, and particularly relates to a preparation method of trifluoro propionic acid. Background The trifluoropropionic acid is colorless, toxic, strong corrosive and transparent liquid with acidic peculiar smell, has a boiling point of 146 ℃, a melting point of 97 ℃ and a density of l.359g/cm < 3 >, and can be mutually dissolved with water and various organic solvents. The trifluoropropionic acid contains trifluoromethyl strong electron withdrawing groups, and has different physicochemical properties from other aliphatic carboxylic acid substances. Because of the strong electron withdrawing property of the CF3 group, the trifluoro propionic acid presents stronger acidity and polarity, and the acidity is equivalent to hydrofluoric acid and is much stronger than that of common fatty acid. The trifluoropropionic acid can be used as an intermediate for synthesizing medicines and pesticides, can be used as a raw material or an intermediate for synthesizing high-performance materials, is an excellent catalyst, is a high-grade solvent with special purposes, and has wide application prospect. Chinese patent CN101973867 discloses a preparation method of 3, 3-trifluoropropionic acid, which uses 3, 3-trifluoropropanal as raw material, uses mesoporous sulfonic acid as catalyst, and makes oxidation under the action of hydrogen peroxide to obtain the product. Chinese patent CN103965047 discloses a process for preparing 3, 3-trifluoropropionic acid by reacting bromoacetic acid with trifluoromethane in the presence of cuprous chloride and alkali metal t-butoxide. The method has the advantages of large catalyst consumption and high cost. Chinese patent CN107956849 discloses a preparation method of a medical intermediate 3, 3-trifluoro propionic acid, which comprises the steps of firstly taking trifluoro propylene as a raw material, reacting with oxygen under the action of zirconia and ceria, and then adding citric acid, manganese chloride and titanium oxide for reaction to obtain a product. The method is simple to operate, but the reaction process is longer, and the product yield needs to be further improved. Disclosure of Invention The invention aims to solve the defects in the prior art, and provides a preparation method of trifluoro propionic acid. The preparation method of the trifluoro propionic acid comprises the following steps: Adding acetic acid and a certain proportion of catalyst into an autoclave, heating to a certain temperature, starting to introduce trifluoropropene, maintaining a certain reaction pressure, and after the trifluoropropene is introduced for 8-10 hours, cooling, transferring into a flask with a rectifying tower and a condenser, and rectifying under reduced pressure to obtain trifluoropropyl acetate; adding trifluoropropyl acetate and a certain equivalent of methanol into a flask, adding a certain proportion of catalyst, heating and refluxing to react until trifluoropropyl acetate is completely reacted, and then placing the mixture into a rectifying device for rectification to obtain trifluoropropanol; And thirdly, oxidizing the trifluoropropanol and hydrogen peroxide under the action of a catalyst at a fixed reaction temperature to obtain the trifluoropropionic acid. Further, in the first step, the catalyst with a certain proportion is 1-10% of the mass of acetic acid, and the catalyst is boron trifluoride diethyl ether. Further, in the first step, the molar ratio of acetic acid to trifluoropropene is 1-3:1. Further, in the first step, the step of maintaining a certain reaction pressure means that the pressure is maintained to be 1-3MPa. Further, in the first step, the temperature is heated to 120-150 ℃ when the temperature is a certain temperature. Further, in the second step, the equivalent of the methanol is 2-5 times of the mole equivalent. In the second step, the catalyst with a certain proportion is 1-10% of the mass of methanol, and the catalyst is alkali metal salt including one of sodium hydroxide, potassium hydroxide, sodium methoxide, sodium ethoxide, sodium tert-butoxide and potassium tert-butoxide. Further, in the step three, the molar ratio of the trifluoropropanol to the hydrogen peroxide is 1:1.05-1.5, and the concentration of the hydrogen peroxide is 8-27.5%. In the third step, the catalyst is ferric chloride and hydrochloric acid, the amount of the ferric chloride is 0.2-1% of the mass of the hydrogen peroxide, and the amount of the hydrochloric acid is 2-5% of the mass of the hydrogen peroxide. Further, in the third step, the fixed reaction temperature is 60-100 ℃. The method has the advantages of higher yield, simple process conditions, cheaper raw materials and capability of greatly reducing the cost of the trifluoro propionic acid. Detailed Description The following technical solutions in the embodiments of the present invention will be clearly an