Chemistry of hydrocarbon compounds – Unsaturated compound synthesis – By addition of entire unsaturated molecules – e.g.,...
Reexamination Certificate
2000-01-14
2002-04-23
Dang, Thuan D. (Department: 1764)
Chemistry of hydrocarbon compounds
Unsaturated compound synthesis
By addition of entire unsaturated molecules, e.g.,...
C585S515000, C585S520000, C585S521000, C585S526000, C585S255000, C585S310000, C585S316000
Reexamination Certificate
active
06376731
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for the selective dimerization of isobutylene and especially to the use of C
3
and/or C
4
alkane as dimerization solvent together with the provision of tertiary butanol as a selectivity enhancing modifier during the dimerization.
2. Description of the Prior Art
The oligomerization of olefins such as isobutylene using acidic catalysts is a known reaction.
As described in U.S. Pat No. 3,760,026, a number of catalysts are known for this reaction including cold sulfuric acid, phosphoric acid on Kieselguhr, silica/alumina sometimes promoted with Ni, Co, Fe, Pt or Pd; activated natural clays plus activating substances such as ZnO metallic phosphates such as those of iron (III) and cerium optionally supported on carriers such as activated carbon, bauxite, activated carbon alone and with metal haliders such as TiCl
2
heteropolyacids such as silicotungstic acid on silica gel and phosphomolybdic acid; BF
3
H
3
PO
4
and BF
3
HPO
3
; dihydroxyfluroboric acid HF and fluorides or oxyfluorides of S, Se, N, P, Mo, Te, W, V and Si boiling below 300° C.; BF
3
dimethyl ether complexes; BF
3
hydrocarbon complexes; BF
3
SO
2
; and AlCl
3
with cocatalysts such as dimethyl ether, HCl, and nitromethane. These catalysts and dimerization processes, including operating conditions, are known in the art.
An especially preferred catalyst is a sulfonic acid-type ion exchange resin such as Amberlyst A-15. U.S. Pat. No. 4,447,668 describes isobutylene dimerization using A-15 with methyl t-butyl ether as solvent.
Our U.S. Pat. No. 5,877,372 describes the selective dimerization of isobutylene using a sulfonic acid resin catalyst, tertiary butanol selectivity enhancing modifier and isooctane diluent.
U.S. Pat. No. 4,100,220 describes isobutylene dimerization using a sulfonic acid resin catalyst and tertiary butanol selectivity enhancing modifier. Minor amounts of butanes are shown in the dimerization feed.
Considerations associated with the isobutylene dimerization involve removal of the substantial heat of reaction and the requirement that high selectivity to the dimer product be maintained. The instant invention provides a process wherein these objectives are achieved.
SUMMARY OF THE INVENTION
In accordance with the present invention, a process is provided for the dimerization of isobutylene in the presence of both a selectivity enhancing amount of tertiary butanol and in the presence of C
3
and/or C
4
, preferably C
4
alkane as diluent. In an especially preferred practice, tertiary butanol such as that derived from the Oxirane propylene oxide/tertiary butanol process is used as starting material and isooctane formed by hydrogenation of dimer is the ultimate product.
BRIEF DESCRIPTION OF THE DRAWING
The accompanying drawing is a schematic representation of an especially preferred practice of the invention.
REFERENCES:
patent: 3760026 (1973-09-01), Reusser et al.
patent: 4100220 (1978-07-01), Bowman et al.
patent: 4165343 (1979-08-01), Levine et al.
patent: 4197185 (1980-04-01), Le Page et al.
patent: 4447668 (1984-05-01), Smith, Jr. et al.
patent: 5847252 (1998-12-01), Stine et al.
patent: 5877372 (1999-03-01), Evans et al.
Evans Thomas I.
Karas Lawrence J.
Rameswaran Ramesh
Arco Chemical Technology, l.p.
Dang Thuan D.
Long William C.
LandOfFree
Selective olefin oligomerization does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Selective olefin oligomerization, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Selective olefin oligomerization will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2842758