CN-117123214-B - Catalyst for preparing hexafluoroisopropanol, preparation method and application thereof

CN117123214BCN 117123214 BCN117123214 BCN 117123214BCN-117123214-B

Abstract

The invention discloses a catalyst for preparing hexafluoroisopropanol by gas phase catalytic hydrogenation, a preparation method and application thereof, wherein the catalyst comprises an active carbon carrier, an active component and an auxiliary agent, wherein the active component and the auxiliary agent are loaded on the active carbon carrier, the active component is Pd, the auxiliary agent is at least one selected from Ce, mo, co, zr and B, and the particle size of the active component and the auxiliary agent is 1-10nm. When the catalyst is used for the catalytic hydrogenation reaction of hexafluoroacetone trihydrate, the fluorine ion content in the product can be controlled below 10ppm, and the catalyst also has high reaction activity and reaction stability.

Inventors

MA CHAOFENG
LI LING
SHI NENGFU
LIU WUCAN
JIN JIAMIN
YU WANJIN

Assignees

浙江蓝天环保高科技股份有限公司
中化蓝天集团有限公司

Dates

Publication Date: 20260505
Application Date: 20220520

Claims (9)

1. A catalyst for preparing hexafluoroisopropanol by gas phase catalytic hydrogenation is characterized in that the catalyst comprises: The activated carbon carrier is pretreated by two steps of inorganic alkali lye alkali washing and organic alkali gas adsorption in sequence; The active component and the auxiliary agent loaded on the active carbon carrier are Pd, the auxiliary agent is at least one selected from Ce, mo, co, zr and B, and the particle size of the active component and the auxiliary agent is 1-10nm; the inorganic alkali liquid is at least one selected from sodium hydroxide solution, potassium hydroxide solution or ammonia water, and the organic alkali gas is at least one selected from triethylamine, pyridine or piperidine.
2. The catalyst for preparing hexafluoroisopropanol by gas phase catalytic hydrogenation according to claim 1, wherein the active component accounts for 0.1-5.0% of the total mass of the catalyst, the auxiliary agent accounts for 0.1-3.0% of the total mass of the catalyst, and the balance is active carbon carrier.
3. The method for preparing the catalyst according to any one of claims 1 to 2, wherein the method comprises the following steps: (1) Alkali washing, namely alkali washing the activated carbon carrier by adopting inorganic alkali liquor, and then washing the activated carbon carrier until the eluate is neutral and drying, wherein the inorganic alkali liquor is at least one of sodium hydroxide solution, potassium hydroxide solution or ammonia water; (2) The method comprises the steps of (1) adsorbing, namely introducing organic alkali gas, and adsorbing on the surface of an activated carbon carrier to obtain a pretreated activated carbon carrier, wherein the organic alkali gas is at least one of triethylamine, pyridine or piperidine; (3) Preparing an active component salt solution and an auxiliary agent salt solution, adding the active component salt solution and/or the auxiliary agent salt solution into a reaction container, adding citric acid or glycerol, impregnating the active carbon carrier at 50-100 ℃ for 1-5 hours, and then dropwise adding ammonia water until the pH value of the solution is 7-9; (4) And taking out the impregnated active carbon carrier, and drying to obtain the catalyst.
4. A process for preparing a catalyst according to claim 3, wherein in step (1), the alkaline washing treatment is carried out at a temperature of 40 to 100℃for a period of 1 to 5 hours.
5. A process for preparing a catalyst according to claim 3, wherein in step (1), the drying temperature is 100 to 120℃and the drying time is 2 to 5 hours.
6. A process for preparing a catalyst according to claim 3, wherein in step (4), the drying temperature is 80 to 120℃and the drying time is 5 to 10 hours.
7. The method for preparing a catalyst according to claim 3, wherein the active component salt solution is selected from the group consisting of palladium chloride and/or palladium acetate of the active component, and the auxiliary agent salt solution is selected from at least one of an auxiliary agent chloride, nitrate and acid salt.
8. A preparation method of hexafluoroisopropanol is characterized in that hexafluoroacetone trihydrate is prepared by gas-phase catalytic hydrogenation, and the method is characterized in that the catalyst prepared by any one of the preparation methods of claims 1-2 or any one of the preparation methods of claims 4-7 is used as a reaction catalyst, the reaction temperature is 110-200 ℃, and the reaction pressure is normal pressure.
9. The method for preparing hexafluoroisopropanol according to claim 8, wherein the catalyst is subjected to reduction treatment before the reaction, the reduction treatment step comprises the steps of loading the catalyst into a reactor, introducing a hydrogen-nitrogen mixed gas for heating reduction, wherein hydrogen accounts for 10% -60% of the volume of the hydrogen-nitrogen mixed gas, the reduction temperature is 200-300 ℃, and the reduction time is 1-3 hours.

Description

Catalyst for preparing hexafluoroisopropanol, preparation method and application thereof Technical Field The invention relates to the field of catalysis, in particular to a catalyst for preparing hexafluoroisopropanol by gas-phase catalytic hydrogenation of hexafluoroacetone trihydrate, a preparation method and application thereof. Background Hexafluoroisopropanol is an important fine fluorine-containing chemical, can be used for preparing high-end fine fluorine-containing chemicals such as anesthetic sevoflurane, refrigerant, lithium battery additives and the like, and is also widely used in the organic synthesis of medicines and pesticides. Meanwhile, hexafluoroisopropanol has strong polarity, is miscible with water and many organic reagents, is heat-resistant and allows ultraviolet rays to pass through, and is therefore an ideal solvent for many polymers. The process for preparing hexafluoroisopropanol by catalytic hydrogenation by taking hexafluoroacetone as a raw material has the advantages of atom economy, high yield and the like, and becomes a main industrial method for producing hexafluoroisopropanol at present. According to different existence forms of hexafluoroacetone as a raw material, the method can be divided into a catalytic hydrogenation process taking gaseous hexafluoroacetone as a raw material and a catalytic hydrogenation process taking hexafluoroacetone hydrate as a raw material. The catalytic hydrogenation process with gaseous hexafluoroacetone as material is to react gaseous hexafluoroacetone with hydrogen to obtain hexafluoroisopropanol. In the process, the gaseous hexafluoroacetone has the problems of low boiling point, very high toxicity, difficult transportation and storage and the like. The catalytic hydrogenation process using hexafluoroacetone hydrate as raw material can overcome the above-mentioned defects. The catalytic hydrogenation process using hexafluoroacetone hydrate as raw material comprises liquid phase hydrogenation process and gas phase hydrogenation process, wherein the liquid phase hydrogenation process has the defects of longer reaction time, higher reaction pressure and the like, is intermittent reaction, and is unfavorable for industrial continuous production. The gas-phase catalytic hydrogenation process using hexafluoroacetone hydrate as raw material refers to a method for preparing hexafluoroisopropanol by using hexafluoroacetone hydrate as raw material and adopting a fixed bed gas-phase catalytic hydrogenation process after vaporization, and has the advantages of mild reaction conditions, high product yield, contribution to industrial continuous production and the like, and has good development prospect. Patent CN102274734a discloses that a catalyst using palladium and copper as a first catalyst, K, la or Bi as a second catalyst, and active carbon as a carrier is used for the reaction of preparing hexafluoroisopropanol by gas phase hydrogenation of hexafluoroacetone hydrate, and has the advantages of good catalytic activity, good product selectivity, etc., but does not disclose the fluoride ion content in the product. Patent CN111790401a discloses the application of a catalyst using palladium metal as an active component, ni, cr or Cu as an auxiliary agent, and carbon material as a carrier in synthesizing hexafluoroisopropanol, which can solve the problems of large noble metal dosage, low activity and short service life in palladium-carbon catalysts, but the content of fluoride ions in the product is not disclosed. In fact, the present inventors have found that, in the existing noble metal catalytic system used in the gas phase catalytic hydrogenation process using hexafluoroacetone hydrate as a raw material, the product has a problem of high fluoride ion content, such as the use of commercial Pd/AC, pd-Cu/AC and Pd-Ni/AC catalysts, and the fluoride ion content in the product is up to more than 1000 ppm. The high content of fluoride ions is easy to combine with free water in the product to generate hydrofluoric acid, has a corrosion effect, and not only corrodes equipment, but also causes loss of noble metal of the catalyst and poisoning of the catalyst. Therefore, the catalyst which has high activity and high stability and can inhibit the content of fluoride ions in the product is developed, and has important significance for realizing the industrial production of preparing hexafluoroisopropanol by gas-phase catalytic hydrogenation of hexafluoroacetone trihydrate as a raw material. Disclosure of Invention In order to solve the technical problems, the invention provides a catalyst which can control the content of fluoride ions in a product to be below 10ppm, has high reaction activity and reaction stability and is used for preparing hexafluoroisopropanol by taking hexafluoroacetone trihydrate as a raw material through gas-phase catalytic hydrogenation. The invention aims at realizing the following technical scheme: a catalyst for vapor phase catalytic hydrog