Development Of New Production Technology For The Green Refrigerant HFO-1234YF

Because of the ever increasingenvironment problems, scientists have to develop environmental friendly refrigerants.2,3,3,3-Tetrafluoropropylene (HFO-1234yf) has been proved to be a promising substitute due to its zero Ozone Depletion Potential (ODP), and very low Global Warming Potential(GWP)of 4. So far, many patents have been issued by Honeywell and DuPont with low yield and harsh reaction conditions. For this reason, it is necessary to develop a new and economic technology route.For preparing HFO-1234yf, the key is to prepare halogenated propane, and then converted it to product by fluorination and elimination reactions. In this paper, we designed some new methods to prepare halogenated propane through addition reaction between unsaturated hydrocarbon with alkyl halides, and Grignard reagents reaction with acetyl chloride or halogenated ethanes.1. Addition reaction between tetrachloroethyleneand bromomethaneunder radical and electrophilic mechanism. In the radical additionmechanism, we tried different catalysts, including UV irradiation, potassium persulfate, FeCl3/Fe, CuSO4/CuCl, AIBN, and di-tert-butylperoxide. Besides, the influence of reaction conditions was studied including time, amount of catalyst, and temperature. The result shows that the addition reaction did not occur due to the high steric hinderance of tetrachloroethene. But AIBN and di-tert-butylperoxide can initiate the production of free radicals and the resultant products like hexachloroethane, pentachloroethane chloroform and other substances. In the electrophilic addition conditions, two catalysts, viz. AICl3 and [BMIM][Al2Cl7],were studied at different temperatures, and no reaction was taken place. In contrast, some radical addition happened at high temperature, producing pentachloroethane and hexachloroethane. This reaction route is novel although it is of little practical significance.2. The addition reaction between carbon tetrachloride and acetylene was studied at different temperature with catalyst CuCl or HgCl. The result shows tetrachloropropene product was produced using CuCl catalyst. The reaction condition is mild, and the reaction degree is high, but the side reactions lead to a poor selectivity and low yield.3. Two Grignard reagents, viz. CF3MgBr and CH3MgBr, were prepared successfully. CF3MgBr is found to be stable and doesn’t react with acetyl chloride. But it has great practical value for its abundant fluorine content. In contrast, CH3MgBr can react with CF3CF2Cl to produceperfluoropropane, and the influence factors were studied, namely temperature, reaction time and solvent. The conversion rate is found to be increased first and then decreased with raising the temperature. Under optimum conditions, i.e. reaction temperature 60℃ and reaction time 12 h, the conversion rate is 13.5% with selectivity of the product of 88.4% and yield of 11.7%.This route is worthy of further study for its mild conditions, simple process, easy accessible of reacting materials and the high selectivity.