| 摘要 |
The invention is concerned with a catalyst comprising a matrix, a MFI type zeolite and at least one group VIII element, in which the crystals of the MFI type zeolite are desaluminated on their outer surface by at least one treatment with at least one solution of a fluorosilicate of a cation selected from the group formed by NH4+, alkylammoniums, K+, Na+, Li+, Ba2+, Mg2+, Cd2+, Cu+, Cu2+, Ca2+, Cs+, Fe2+, Co2+, Pb2+, Mn2+, Rb+, Ag+, Sr2+, Zn2+, Tl+ and H+, the global desalumination rate of said MFI zeolite thus treated being less than 5 atomic per cent.
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