Catalysts Studies On Fluorination From Tetrachloropropene To Tetrafluoropropene(HFC-1234yf)

Along with upgrading of CFCs material and widely use of HFCs, Kyoto Protocol begins to forbid many HFCs result in high GWP value. It is well known that the typical characteristic of2,3,3,3-tetrafluoropropene (HFC-1234yf) is low GWP, GWP=4. For replacing the present Mass of the use of automotive air conditioning refrigerant1,1,1,2-tetrafluoroethylane (HFC-134a), it is a potential and direct economic alternative project. In this paper, we researched that materials of1,1,2,3-tetrachloropropene was purified by rectification and then was reacted with HF to prepare trifluorochloropropene and tetrafluoropropene. After reaction, the main products and raw materials which did not react would be tested by GC-MS2010, then phase structure, surface acid properties and carbon deposition of used Catalyst were characterized by XRD、NH3-TPD、Raman.In this paper, the catalysts of Cr-Al system were prepared by precipitation. By changing oxide of chromium and aluminum component, we can gain the information of the reaction. With the temperature increased, the research found that selectivity and conversion of CF3CCl=CH2have increased. At low temperature, more Al content, a mass of coke led to deactivation of catalysts and decline of conversion and selectivity in violent reaction. By using more Cr content, selectivity of CF3CCl=CH2increased, but the conversion is not the best. When the ratio Cr/Al is8:2, the bicomponent8Cr2Al catalyst has better selectivity and conversion (both are more than98%).In this paper, a series catalyst of Cr-M (La, Mg, Fe and Al) which the mol ratio is8:2were prepared by precipitation. And then the information of the synthetic reaction of2,3,3,3-tetrafluoropropene was collected. When the reaction temperature is250℃, it safely draws a conclusion that the catalyst Cr2O3has the low conversion. Because of coke; the catalyst8Cr2La easily deactivate and result in converting into CF2=CClCH2Cl; Using the catalyst8Cr2Fe, there are many side reactions and serious isomerization, what’s more, the catalyst of8Cr2Mg have a longer active induction period. By comparing, catalyst8Cr2Al has better selectivity, conversion and stability.Finally, this paper describes a method about the reaction of series reactor. The research information includes the influence of different temperature and catalysts in synthetic reaction of2,3,3,3-tetrafluoropropene by gas phase fluoridation. When the same catalyst was used in the series reactor, catalytic reaction has strong inertness, selectivity of HFC-1234yf is not better than5.4%. However, with the preparation of CF3CF=CH2, series reactor use two different kinds of catalysts have obvious effect. After reaction, the selectivity of HFC-1234yf is23%and conversion of raw is98%.