Multinuclear MAS NMR investigation of zeolites reacted with chlorofluorocarbons

Multinuclear (Na-23, Al-27, Si-29, C-13) MAS NMR techniques were used for i nvestigation of surface reaction of Y-type zeolites with CFCs (CCl4, CCl3F, CCl2F2, CClF3, CF4) and HCFC (CHClF2). The hydrogen containing derivative reacts slowly. Those possessing more than 2 F atoms can be regarded as stab le unreactive materials. CCl4, CCl3F, CCl2F2 react strongly with the zeolit es. The reaction of HCFC with zeolites has a different mechanism to the oth er CFCs tested. On the basis of multinuclear NMR results a mechanism is giv en for the decomposition of HCFC. (C) 1999 Elsevier Science B.V. All rights reserved.