Dehydration of alcohols on crystalline silicates

摘要

The present invention relates to a process for the dehydration of at least an alcohol to make at least an olefin, comprising:
introducing in a reactor a stream (A) comprising at least an alcohol, optionally water, optionally an inert component, contacting said stream with a catalyst in said reactor at conditions effective to dehydrate at least a portion of the alcohol to make an olefin,recovering from said reactor an olefin containing stream (B),Whereinthe catalyst is:
a crystalline silicate having a ratio Si/Al of at least about 100, ora dealuminated crystalline silicate, ora phosphorus modified zeolite,the WHSV of the alcohols is at least 2 h−1,the temperature ranges from 280° C. to 500° C.;It relates also to the same process as above but wherein the catalyst is a phosphorus modified zeolite and at any WHSV.;The partial pressure of the alcohol in the dehydration reactor advantageously ranges from 1.2 to 4 bars absolute (0.12 MPa to 0.4 MPa), the temperature of the dehydration reactor ranges advantageously from 300° C. to 400° C. and the alcohol is selected among ethanol, propanol, butanol and phenylethanol.

主权项

1. A process for the dehydration of an alcohol having at least 2 carbon atoms to produce a corresponding olefin comprising:
forming a catalyst comprising a phosphorous modified zeolite by: selecting a zeolite with an Si/Al ratio between 4 and 30 from an H+ or NH4+ form of MFI, MEL, FER, MOR, or clinoptilolite; steaming the zeolite at a temperature ranging from 400 to 870° C. for 0.01 to 200 hours; leaching the zeolite at conditions effective to remove at least 10% of Al from the zeolite; introducing P at conditions effective to introduce at least 0.05 wt % of P; separating solids from liquids; and calcining; introducing a first stream into a reactor, wherein the first stream comprises an alcohol; contacting the first stream with the catalyst in the reactor at conditions effective to dehydrate at least a portion of the alcohol to produce an olefin; and recovering from the reactor a second stream comprising an olefin; wherein the reactor is operated under conditions comprising an alcohol WHSV of at least 2 h−1 and temperatures ranging from 280 to 500° C.