Research On The Preparation Of A Novel Green Refrigerant HFO-1234yf(ze)

Existing traditional fluorine-contained refrigerants have been known to cause damage to the ozone layer, lead to greenhouse effect, and threaten human survival environment. Thus, it is extremely significant to develop novel green refrigerants. ODP of HFO-1234yf and HFO-1234ze is both 0 and GWP is 4 and 6, respectively. Both refrigerants are environmental friendly, and wildly accepted as green replacements for HFC-134a. Currently, the synthesis technologies of HFO-1234yf（ze） are almost all monopolized by foreign companies. Consequently, it is necessary to explore an economic, environmentally friendly and efficient way to synthesize HFO-1234yf（ze） independently.In existing synthesis technologies of HFO-1234yf（ze）, C1 and C2 are mainly employed as raw materials, then synthesize allyl halogenated propane/halogenated C3 intermediates through addition reactions or substitution reactions, and then hydrogenation, fluoridation, dehydrohalogenation methods are used to prepare HFO-1234yf（ze）. Therefore, the key step of the preparative technique of HFO-1234yf（ze） is the novel process to synthesize C3 intermediates. In this study,3 routes of the synthesis of C3 intermediates were researched. Firstly, Acetylene was used as the main raw material to react with halogenated hydrocarbon. Secondly, metal acetylene was used as the main raw material to react with halogenated hydrocarbon. Thirdly, Grignard reagent was prepared to react with halogenated hydrocarbon.Initially, feasibility of employing acetylene as raw material to react with CHF₃, CCl4, CF₃Br to synthesize intermediates respectively was studied. It was found in this study that acetylene was carbonized easily under high temperature, but not reacted with CHF₃ forming CF₃C≡CH through free radical coupling reaction. Deep electrophilic substitution occurred between acetylene and CCl4 when catalyzed by AlCl3, and carbon material was generated, without formation of single substituted product CCl3C≡CH. Addition reaction was impossible between C2H2 and CF₃Br under catalyst of AlCl3. In order to improve the reaction selecitity, HgCl2 catalyst was used to reasearch the possibility of the electrophilic addition reaction between C2H2 and CF₃Br. Again, C2H2 was self-polymerized, without formation of the target product CF₃C=CHBr.In addition, substitution reaction between sodium acetylide and CH₃Br was studied. Nucleophilic substitution reactions were also researched among metal acetylide such as sodium acetylide, zinc acetylide, lithium acetylide ethylenediamine complex, calcium acetylide, magnesium acetylide and CCl4, respectively. In this study, it was found that in aprotic polar solvent, allylene was generated by sodium acetylide and CH₃Br, and the selectivity was high. Deep substitution reaction was occurred between sodium acetylide and both CCl4 and CF₃Br. Deep substitution reaction was occured between acetylene lithium and CC14, and a large number of black carbon material were generated. But the amount of the substituted bromine was far more than fluoro-substitution, and CF₃C=CH might be generated with appropriate controlling of the reaction conditions. Substitution reactions were not observed between acetylene zinc, acetylene calcium, acetylene magnesium and CF₃Br, but multi-substitution reactions occured between CCl4 and them. Thus, the reaction activity of CF₃Br is much lower than CCl4.Finally, Grignard reaction employing a serious of Grignard reagent to synthesize C3 intermediate was studied. In this study, CH₃MgBr Grignard reagent was successfully prepared, and it can react with CF₃CF₂Cl to generate the target product CF₃CF₂CH₃. Meanwhile, there were also fluorine/chlorine multi-substitution reactions, which worth further studies. Moreover, another two Halogenated hydrocarbon Grignard reagent CF₃MgBr and CH₃CF₂MgCl were successfully prepared. However, CH₃CCl3 and CF₃CF₂Cl were unable to synthesis CH₃CCl2MgCl and CH₃CF₂MgCl, the former was as a result of deep substitution reaction and the latter was because of the low activity of fluoride halogenated hydrocarbon. No substitution reaction was observed between the Grignard reagent CF₃MgBr and CH₃CF₂Cl, and between CH₃CF₂MgCl and r. That was because the reaction activity of fluorine contained Grignard reagent was much lower than conventional Grignard reagent and halogenated hydrocarbon.