Kwang Hun Lim and Clare P. Grey
19F/23Na Cross polarization (CP) MAS NMR experiments of various asymmetric hydrofluorocarbons (HFCs) such as CF3CFH2 (HFC-134a) and CF2HCFH2 (HFC-143) adsorbed on zeolite NaY, demonstrate that the hydrogen-containing groups are bound more strongly to the zeolite framework, in the order CF3<<CF2H<CFH2; the results help explain the preferential binding of CF2HCF2H (HFC-134) over HFC-134a, and hence the effectiveness of basic zeolites in the separation of HFC-134/134a gas mixtures.