GB2145415A

GB2145415A - Isopropanol and tert-butanol mixtures from liquid petroleum gas

Info

Publication number: GB2145415A
Application number: GB8421082A
Authority: GB
Inventors: Michael John Pettman
Original assignee: Humphreys and Glasgow Ltd
Current assignee: Humphreys and Glasgow Ltd
Priority date: 1983-08-23
Filing date: 1984-08-20
Publication date: 1985-03-27
Also published as: GB8421082D0; GB8322574D0

Abstract

A process for producing a mixture of isopropyl alcohol and tertiary butyl alcohol comprises separating liquid petroleum gas (LPG) or natural gas liquid (NGL) into a mixture of propane and iso-butane, dehydrogenating the mixed C3 and iso C4 stream and hydrating the resulting mixed olefins as a single stream. The alcohol mixture is useful as an octane improver and additive for gasoline.

Description

SPECIFICATION Production of mixed alcohols In view of the difficulties of producing mixed alcohols from synthesis gas, the present invention describes a process for the production of mixed alcohols from LPG or NGL liquids.

The present invention comprises: separating the LPGs using distillation to give overhead a mixture of C3 and iso C4 and a bottom product of n 045.

The normal C4 stream may be isomerised and recycled as feed to the above distillation stage.

The mixed Cg and iso C4 stream is dehydrogenated as a single stream, i.e. the CQ and iso C4 are simultaneously dehydrogenated to propylene and isobutylene in a single unit.

Finally the mixed stream of propylene and isobutylene are hydrated, using well known technology, to isopropanol and tertiary butyl alcohol.

The advantage of such a process is that starting with LPG or natural gas liquids, any ratio of isopropyl alcohol and tertiary butyl alcohol is possible, although excess Cs or iso C4 material may have to be coproduced. It is also possible to produce methanol by well known means from the normal C4 stream if this is not isomerised.

The technology for each stage is well known and no distillation to remove water is required compared with the production of mixed alcohol streams via the synthesis gas route, i.e. by the route which would break up the LPG or NGL materials into a synthesis gas, i.e. a gas containing hydrogen, carbon monoxide and carbon dioxide. A further advantage is that by such means LPG fractions may be converted into fractions which may be added to gasoline without the drawbacks associated with the production and addition of methanol, e.g. phase separation and vapour locking in the ultimate vehicle.

1. A process for the production of isopropyl alcohol and tertiary butyl alcohol characterised by the following features: a) separating LPGs to give a mixture of C3 and iso C4 paraffins b) dehydrogenating these as a single stream c) hydrating the resulting olefins, again as a single stream to the said products.

2. A process as claimed in Claim 1 wherein the ratio of isopropyl alcohol to tertiary butyl alcohol is adjusted by separating by distillation some C3 material or C4 material prior to dehydrogenation.

3. A process as claimed in Claim 1 wherein the ratio of isopropyl alcohol to tertiary butyl alcohol is adjusted by separating by hydration some C3 material or C4 material prior to dehydrogenation.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Production of mixed alcohols In view of the difficulties of producing mixed alcohols from synthesis gas, the present invention describes a process for the production of mixed alcohols from LPG or NGL liquids. The present invention comprises: separating the LPGs using distillation to give overhead a mixture of C3 and iso C4 and a bottom product of n 045. The normal C4 stream may be isomerised and recycled as feed to the above distillation stage. The mixed Cg and iso C4 stream is dehydrogenated as a single stream, i.e. the CQ and iso C4 are simultaneously dehydrogenated to propylene and isobutylene in a single unit. Finally the mixed stream of propylene and isobutylene are hydrated, using well known technology, to isopropanol and tertiary butyl alcohol. The advantage of such a process is that starting with LPG or natural gas liquids, any ratio of isopropyl alcohol and tertiary butyl alcohol is possible, although excess Cs or iso C4 material may have to be coproduced. It is also possible to produce methanol by well known means from the normal C4 stream if this is not isomerised. The technology for each stage is well known and no distillation to remove water is required compared with the production of mixed alcohol streams via the synthesis gas route, i.e. by the route which would break up the LPG or NGL materials into a synthesis gas, i.e. a gas containing hydrogen, carbon monoxide and carbon dioxide. A further advantage is that by such means LPG fractions may be converted into fractions which may be added to gasoline without the drawbacks associated with the production and addition of methanol, e.g. phase separation and vapour locking in the ultimate vehicle. CLAIMS