O3 catalyst comprising of a mixture of from 2.5 to 7.5% wt of Cr2 O3, 5 to 17.5% wt of Al2 O3 and {HEAD ~ 75 to 85% wt} of a Zn ZSM 5 zeolite or {TAIL ~ a Zn ZSM 5 zeolite/asbestos} 
of
O3 catalyst comprising of a mixture of from 2.5 to 7.5 % wt of Cr2 O3 , 5 to 17.5 % wt of Al2 O3 and { HEAD ~ 75 to 85 % wt } of a Zn ZSM 5 zeolite or { TAIL ~ a Zn ZSM 5 zeolite / asbestos }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL