Effects of yttrium-doping on the performance of Cr2O3 catalysts for vapor phase fluorination of 1,1,2,3-tetrachloropropene

•Promoter yttrium can efficiently improve the selectivity of Cr2O3 catalyst.•1Y2O3-Cr2O3(F) catalyst maintains the highest selectivity after 100 h reaction.•Surface CrOxFy content of Y2O3-Cr2O3(F) catalysts is responsible for selectivity.

The synthesis of 2-chloro-3,3,3-trifluoropropene (HCFC-1233xf) from 1,1,2,3-tetrachloropropene was performed over a series of Y2O3-Cr2O3(F) catalysts and the effect of yttrium-doping on the performance of Cr2O3 catalysts was investigated. Various characterization results showed that the addition of yttrium in the Cr2O3 led to the formation of high valent Cr species in the samples, which could be consequently converted to catalytically active CrOxFy species during the pre-fluorination process. Although the Cr2O3 catalyst with or without yttrium-doping showed very high 1,1,2,3-tetrachloropropene conversion in long term reaction, the addition of yttrium in the Cr2O3 helped to maintain the high selectivity to HCFC-1233xf, with the highest selectivity (97%) obtained on a 1 mol% yttrium-doped Cr2O3 after 100 h reaction. X-ray photon spectroscopy results on the spent Cr2O3(F) and 1Y2O3-Cr2O3(F) catalysts indicated that the content of the active CrOxFy species declined after 70 h reaction, which was responsible for the loss of selectivity (from 97% to 88%), while it remained almost unchanged on the spent 1Y2O3-Cr2O3(F) catalyst.

Graphical abstractThe conversion of 1,1,2,3-tetrachloropropene is 99.6% and selectivity to HCFC-1233xf is 97.0% over 1Y2O3-Cr2O3(F) catalyst after 100 h reaction.Figure optionsDownload full-size imageDownload as PowerPoint slide