The Future Development of the Fourth Generation Refrigerant HFO-1234yf

As we all know, with the introduction of more and more global environmental regulations and policies aimed at reducing the greenhouse effect of HFCs, the fourth-generation refrigerant HFO-1234yf has attracted much attention. The product features zero ozone potential (ODP), slightly flammable and low global warming potential (GWP), and is a new generation of ODS alternatives to hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) – Hydrofluoroolefins (HFO). In recent years, with the recognition of HFO-1234yf by the European Union, HFO-1234yf is most likely to replace HFC-134a as a new generation of automotive refrigerants. Mainly used in automobiles and refrigerators, HFO-1234yf is also used in many large stationary and commercial refrigeration equipment.

The current mainstream HFO-1234yf production processes are as follows:

1. Production of HFO-1234yf by addition-elimination method using hexafluoropropene (HFP) as raw material.

First, hydrogen and hexafluoropropene (HFP) are subjected to a catalytic addition reaction to generate hexafluoropropane, and then the elimination reaction is performed to generate pentafluoropropene (HFO-1225ye); the generated pentafluoropropene (HFO-1225ye) is also catalytically added to hydrogen. The reaction produces pentafluoropropane, and then the elimination reaction finally produces tetrafluoropropene (HFO-1234yf). The conversion rate of the raw material hexafluoropropylene to pentafluoropropylene is 98.2%, the conversion rate of pentafluoropropylene to tetrafluoropropylene is 97.1%, and the total conversion rate is 95.2%.

2. Production of HFO-1234yf by dehydrofluorination method using pentafluoropropane (HFC-245cb) as raw material.

1,1,2,3-Tetrachloropropene (TCP) was synthesized from pentafluoropropane (HFC-245eb) in the liquid phase, and pentafluoropropane (HFC-245eb) was then removed from HF to produce tetrafluoropropene (HFO-1234yf).

3. Using 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) as raw material to produce HFO-1234yf by fluorine and chlorine exchange method.

2-chloro-3,3,3-trifluoropropene is produced by reacting anhydrous hydrogen fluoride with a specific chlorine-containing compound in the gas phase in the presence of a fluorination catalyst while heating; 2-Chloro-3,3,3-trifluoropropene is reacted with anhydrous hydrogen fluoride in the gas phase in the presence of a catalyst to produce 2,3,3,3-tetrafluoropropene (HFO-1234yf).

4. Tetrafluoropropene (HFO-1234yf) is obtained by pyrolysis of monochloromethane and tetrafluoroethylene (TFE) as raw materials.

5. The tetrafluoropropene (HFO-1234yf) was prepared from the mixture of hexafluoropropane (HFC-236ea) and pentafluoropropane (HFC-245eb).