CN108246277B

CN108246277B - Method for efficiently synthesizing trifluoroiodomethane

Info

Publication number: CN108246277B
Application number: CN201810235825.XA
Authority: CN
Inventors: 赵毅; 赵趫; 王天源; 计燕秋; 张琳; 石琳; 刘颖
Original assignee: Dalian Kelide Optoelectronic Mat Co ltd
Current assignee: Dalian Kelide Optoelectronic Mat Co ltd
Priority date: 2018-03-21
Filing date: 2018-03-21
Publication date: 2023-04-11
Anticipated expiration: 2038-03-21
Also published as: CN108246277A

Abstract

The invention discloses a method for efficiently synthesizing trifluoroiodomethane, which is implemented by reacting CF (carbon fiber) ₃ COOH steam and iodine steam react under the action of a catalyst to generate trifluoroiodomethane; the catalyst takes active carbon or graphene as a carrier to load 1-10wt% of KNO ₃ And 2 to 7wt% of RbNO ₃ The catalyst of (1); then sequentially passing through NaOH solution, silica gel and molecular sieve to effectively remove CF ₃ Impurities and moisture in I, thereby efficiently collecting high-purity CF ₃ And (I) products. The method has the advantages of high reaction rate, good selectivity, high yield, high reactant utilization rate and energy conservation, is expected to realize industrial production, and meets the current market demand.

Description

Method for efficiently synthesizing trifluoroiodomethane

Technical Field

The invention relates to a method for efficiently synthesizing trifluoroiodomethane.

Background

Trifluoroiodomethane (CF) ₃ I) Has a potential greenhouse effect (GWP) of less than 5 and an Ozone Depletion Potential (ODP) of 0, and is listed as a main component of the 3 rd generation environment-friendly refrigerant by the United nations. Except for being as newBesides the gaseous extinguishing agent and the refrigerant, the gas extinguishing agent also has wide application prospect in other fields such as fluorine-containing intermediates, semiconductor etching, foaming agents and the like.

CF ₃ I literature report CF ₃ I, a plurality of synthesis processes are provided, and the main methods comprise:

(1) Pyrolysis of perfluorocarboxylic acid salts: with CF ₃ COM (M = Ag, na, K, hg, pb, ba) and iodine (I) ₂ ) Preparing CF by heating and decomposing in strong polar solvent ₃ I, which was the earliest synthetic method proposed to be of industrial and practical value, (j.am. Chem. Soc.1950 (72): 584-587.3806-7, j.chem. Soc.,1951 (2): 584-587.). The pyrolysis yield is high in the form of silver salts, but the price is high. Paskovich et al found that sodium or potassium salts increase CF under dimethyl formamide (DMF) reflux ₃ I yields were around 70% (J.org.chem., 1967, 32 (3): 833-835.). Sihuatang, etc. uses sulfolane as solvent instead of DMF to obtain CF ₃ The yield of I was around 80% (Chemicals, 1989, 11 (2): 123.).

(2) Trifluoromethane iodination method: japanese patent JP52068110 reports trifluoromethane (CF) ₃ H) And I ₂ Preparing CF by taking active carbon loaded alkali metal or alkaline earth metal as a catalyst as a raw material ₃ I. The catalyst shows better catalytic activity, the catalyst has serious carbon deposition and short service life due to high reaction temperature, and the generated high polymer increases the cyclic utilization of unreacted I ₂ The difficulty of (2).

(3) The French patent FR2794456 proposes pentafluoroethane (C) ₂ F ₅ H) And I ₂ The process has a catalytic system similar to that of trifluoromethane iodination, and CF can be obtained by passing the raw material gas through an activated carbon-supported alkali metal or alkaline earth metal catalyst bed ₃ I。

In summary, the prior art for preparing CF ₃ The method I has a series of problems of high raw material price, high cost, large reaction solvent consumption, low product yield, poor selectivity, low raw material utilization rate and the like. Therefore, a CF with simple operation and high selectivity is found ₃ The I synthetic route is of critical importance.

Disclosure of Invention

In order to solve the above problems, the present invention aims to provide a synthetic CF having a simple operation and a high product selectivity ₃ The method of I. In order to achieve the purpose, the invention is realized by the following technical scheme:

high-efficiency synthesis of CF ₃ Method of I, CF ₃ COOH steam and iodine steam react under the action of catalyst to produce trifluoro iodomethane;

the catalyst takes active carbon or graphene as a carrier to load 1-10wt% of KNO ₃ And 2 to 7wt% of RbNO ₃ The catalyst of (1); CF ₃ The molar ratio of COOH vapor to iodine vapor is 1:1 to 2:1; the reaction temperature is 450-550 ℃; the reaction time is 10-15min; CF (compact flash) ₃ The flow rate of COOH steam is 10-20mL/min.

Catalyst Synthesis of KNO ₃ And RbNO ₃ Dissolving in water, adding active carbon or graphene, performing ultrasonic treatment for 30min, and standing overnight; filtering, drying the solid isolate at 100 ℃ for 5h, and then calcining at 500 ℃ for 2h in a high-purity nitrogen atmosphere to obtain the catalyst. KNO ₃ And RbNO ₃ The dosage ratio of the water to the water is 3-8g/500ml.

Further, in the technical scheme, the obtained trifluoroiodomethane is sequentially introduced into a first collector, a second collector, an alkaline washing tank, a dryer and an adsorber to remove impurities and water; the outside of the first collector is heated by circulating water; the alkali liquor of the alkaline washing tank is NaOH solution; the drying agent in the dryer is silica gel; the adsorbent in the adsorber is a molecular sieve.

Further, in the technical scheme, the temperature of the circulating water outside the primary collector is 70-80 ℃; the concentration of NaOH solution in the alkaline washing tank is 0.1-5%; the adsorbent in the adsorber is a 5A molecular sieve.

Further, in the above technical solution, the cold trap is used to receive trifluoroiodomethane.

Further, in the technical scheme, the temperature of the collected trifluoroiodomethane cold trap is-70 ℃.

Further, in the above technical solution, CF ₃ COOH vapor is from temperatureIs produced by vaporization of a vaporizer at 100 ℃; the iodine vapor was generated by an iodine evaporator at a temperature of 200 deg.c.

Further, in the technical scheme, the reaction device comprises a reactor, and the inlet of the reactor is connected with CF ₃ COOH vaporizer and iodine vaporizer; the outlet of the reactor is sequentially connected with a first collector, a second collector, an alkaline washing tank, a dryer, an absorber and a cold trap.

The invention provides a high-efficiency synthetic CF ₃ I method is to load 1-10wt% of KNO by using active carbon or graphene as a carrier ₃ And 2 to 7wt% of RbNO ₃ As a catalyst, use CF ₃ The COOH vapor and iodine vapor chemically react in the high temperature reactor to form CF ₃ I, then sequentially passing through NaOH solution, silica gel and molecular sieve to effectively remove CF ₃ Impurities and moisture in I, CF synthesized therefrom ₃ The yield of the I is up to 90 percent, and the catalyst is suitable for selection, and the process steps are reasonable in design, so that the reaction rate can be accelerated, the yield can be increased, the utilization rate of reactants can be increased, the energy is saved, the industrial production is expected to be realized, and the current market demand is met.

Drawings

FIG. 1 is a flow chart of the method for efficiently synthesizing trifluoroiodomethane provided by the invention.

Detailed description of the preferred embodiments

Example 1

1. Synthesizing a catalyst: 3.0g of KNO ₃ And 5g RbNO ₃ Dissolving in 500mL water, adding 100g active carbon, performing ultrasonic treatment for 30min, and standing overnight; filtering, drying the solid isolate at 100 ℃ for 5h, and then calcining at 500 ℃ for 2h in a high-purity nitrogen atmosphere to obtain the catalyst.

2. Synthesis of CF ₃ I

(1)CF ₃ COOH vapor and iodine vapor are mixed in a molar ratio of 1:1, entering a reactor with the temperature of 500 ℃, filling 100g of catalyst in the reactor, and controlling CF ₃ The flow rate of COOH vapor was 20mL/min, CF ₃ Reaction time of COOH and iodine was 10min to form CF ₃ I。

(2) Making the above-mentioned CF ₃ The gas I is sequentially introduced into a first collector, a second collector, an alkaline washing tank, a dryer and an adsorber to remove H ₂ O、CO ₂ And HF and the like. Circulating outside the first-stage collector by using water at 80 ℃; 0.5% NaOH solution in the alkaline wash tank; the drying agent in the dryer is silica gel; the adsorbent in the adsorber is 5A molecular sieve. Finally, the reaction solution passes through a cold trap pair CF at the temperature of-70 DEG C ₃ I solution is received, CF ₃ The yield of I was 84.6%.

Example 2

1. Synthesizing a catalyst: 7.0g of KNO ₃ And 0.7g RbNO ₃ Dissolving in 500mL of water, adding 100g of graphene, carrying out ultrasonic treatment for 30min, and standing overnight; filtering, drying the solid isolate at 100 ℃ for 5h, and then calcining at 500 ℃ for 2h in a high-purity nitrogen atmosphere to obtain the catalyst.

2. Synthesis of CF ₃ I

(1)CF ₃ COOH vapor and iodine vapor in a molar ratio of 2:1, entering a 550 ℃ reactor, filling 100g of catalyst in the reactor, and controlling CF ₃ The flow rate of COOH vapor was 20mL/min, CF ₃ Reaction time of COOH and iodine was 10min to form CF ₃ I。

(2) Making the above-mentioned CF ₃ The gas I is sequentially introduced into a first collector, a second collector, an alkaline washing tank, a dryer and an adsorber to remove H ₂ O、CO ₂ And HF and the like. Circulating outside the first-stage collector by using water at 80 ℃; 0.5% NaOH solution in the alkaline wash tank; the drying agent in the dryer is silica gel; the adsorbent in the adsorber is 5A molecular sieve. Finally, the reaction solution passes through a cold trap pair CF at the temperature of-70 DEG C ₃ I solution to receive, CF ₃ The yield of I was 90.7%.

Claims

1. A method for efficiently synthesizing trifluoroiodomethane is characterized by comprising the following steps:

CF ₃ COOH steam and iodine steam react under the action of catalyst to produce trifluoro iodomethane;

the catalyst is loaded with 1 to 10wt% of KNO by using active carbon or graphene as a carrier ₃ And 2 to 7wt% of RbNO ₃ Of (2) aAn agent; CF ₃ The molar ratio of COOH vapor to iodine vapor is 1:1 to 2:1; the reaction temperature is 450-550 ℃; the reaction time is 10-15min; CF (compact flash) ₃ The flow rate of COOH steam is 10-20mL/min; the yield of trifluoroiodomethane was 84.6% or 90.7%.

2. The method for efficiently synthesizing trifluoroiodomethane according to claim 1, wherein: sequentially introducing the obtained trifluoroiodomethane into a first collector, a second collector, an alkaline washing tank, a dryer and an adsorber to remove impurities and water; the outside of the first collector is heated by circulating water; the alkali liquor of the alkaline washing tank is NaOH solution; the drying agent in the dryer is silica gel; the adsorbent in the adsorber is a molecular sieve.

3. The method for efficiently synthesizing trifluoroiodomethane according to claim 2, wherein: the temperature of the circulating water outside the first-stage collector is 70-80 ℃; the concentration of NaOH solution in the alkaline washing tank is 0.1-5%; the adsorbent in the adsorber is a 5A molecular sieve.

4. The method for efficiently synthesizing trifluoroiodomethane according to claim 2, wherein: the trifluoroiodomethane was received using a cold trap.

5. The method for efficiently synthesizing trifluoroiodomethane according to claim 4, wherein: the temperature of the cold trap for collecting the trifluoroiodomethane is-70 ℃.

6. The method for efficiently synthesizing trifluoroiodomethane according to any one of claims 1 to 5, wherein the method comprises the following steps: CF ₃ The COOH vapor is generated by vaporization of a vaporizer at a temperature of 100 ℃; the iodine vapor was generated by an iodine evaporator at a temperature of 200 deg.c.

7. The method for efficiently synthesizing trifluoroiodomethane according to claim 6, wherein said method comprises the steps of: the reaction device comprises a reactor, wherein the inlet of the reactor is connected with CF ₃ COOH vaporizer and iodine vaporizer; the outlet of the reactor is sequentially connected with a first collectorA collector, a second collector, an alkaline washing tank, a dryer, an absorber and a cold trap.