Decomposition of CH2FCF3 (134a) over metal phosphate catalysts

The decomposition of CH2FCF3 over some phosphate catalysts was studied. CH2FCF3 began to react at 250, 300, and 450 degreesC over Zr-3(PO4)(4), AlPO4, and BPO4, respectively, and the conversion reached 100% at 475, 500, and 700 degreesC, respectively. The primary reaction over Zr-3(PO4)(4) was estimated to be CH2FCF3 + H2O + 1(/)2 O-2 --> 2CO + 4HF, whereas the reactions over AlPO4 and BPO4 were CH2FCF3 + H2O + O-2 --> CO + CO2 + 4HF and CO + 1/2 O-2 --> CO2. Complete decomposition requires both hydrolysis and oxidation. The oxidation activities of these phosphate catalysts are not high enough to accomplish complete decomposition. However, AlPO4-based catalysts can be combined with each Co3O4, Mn2O3, CuO, and Cr2O3 at a phosphate content of 1/10 by volume to make them sustainable at 550-550 degreesC. The addition of Ce to AlPO4 brought about a promotion effect in CH2FCF3 decomposition similar to that for CCl2F2 decomposition. This might suggest a similarity in the reaction mechanism. The primary reaction in the absence of oxygen was estimated to be CH2FCF3 + H2O --> CO + C + 4HF.