The present invention (in a first embodiment) relates to a process for the simultaneous
dehydration and skeletal
isomerization of
isobutanol to make substantially corresponding olefins, having the same number of carbons and consisting essentially of a mixture of n-butenes and iso-
butene, said process comprising:a) introducing in a reactor a
stream (A) comprising
isobutanol, optionally water, optionally an
inert component,b) contacting said
stream with a catalyst in said reactor at conditions effective to dehydrate and skeletal isomerize at least a portion of the
isobutanol to make a mixture of n-butenes and iso-
butene,c) recovering from said reactor a
stream (B), removing water, the
inert component if any and unconverted isobutanol if any to get a mixture of n-butenes and iso-
butene,Wherein,the WHSV of the isobutanol is at least 1 h−1 or the temperature is from 200° C. to 600° C. and the catalyst is capable to make simultaneously the
dehydration and skeletal
isomerization of butene.The catalyst is a crystalline
silicate of the group FER, MWW, EUO, MFS, ZSM-48, MTT, MFI, MEL or
TON having Si / Al higher than 10,or a dealuminated crystalline
silicate of the group FER, MWW, EUO, MFS, ZSM-48, MTT, MFI, MEL or
TON having Si / Al higher than 10,or a
phosphorus modified crystalline
silicate of the group FER, MWW, EUO, MFS, ZSM-48, MTT, MFI, MEL or
TON having Si / Al higher than 10,or a silicoaluminaphosphate
molecular sieve of the group AEL,or a silicated, zirconated or titanated or fluorinated
alumina.Advantageously the stream (B) is fractionated in a step d) to produce a n-butenes stream (N) and to remove the essential part of isobutene optionally recycled with stream (A) to the
dehydration /
isomerization reactor of step b).