Chemistry of hydrocarbon compounds – Adding hydrogen to unsaturated bond of hydrocarbon – i.e.,... – With preliminary diverse conversion
Reexamination Certificate
2000-03-20
2001-08-14
Knode, Marian C. (Department: 1764)
Chemistry of hydrocarbon compounds
Adding hydrogen to unsaturated bond of hydrocarbon, i.e.,...
With preliminary diverse conversion
C585S510000, C585S533000, C203SDIG006
Reexamination Certificate
active
06274783
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a process for the concurrent production and hydrogenation of diisobutene. More particularly the invention relates to a process wherein isobutylene is dimerized and hydrogenated in a single distillation column reactor to produce desirable gasoline blending stocks, specifically the single step process produces 2,2,4-trimethyl pentane (isooctane). The resultant product which may be a mixture of isooctane, other C
8
alkanes or alkenes is a superior blending stock for producing gasolines, including the CARB specifications.
2. Related Art
Conversion of olefins to gasoline and/or distillate products is disclosed in U.S. Pat. Nos. 3,960,978 and 4,021,502 wherein gaseous olefins in the range of ethylene to pentene either alone or in admixture with paraffins are converted into an olefinic gasoline blending stock by contacting the olefins with a catalyst bed made up of a ZSM-5 type zeolite. In U.S. Pat. No. 4,227,992, Garwood and Lee disclose operating conditions for the selective conversion of C
3
+ olefins mainly to aliphatic hydrocarbons. Also, U.S. Pat. Nos. 4,150,062 and 4,211,640 disclose a process for converting olefins to gasoline components. Chang, et al, in U.S. Pat. No. 5,608,133 disclose production of synthetic lubricants by oligomerization of C
2
-C
5
olefins and subsequent hydrogenation of the higher boiling olefins. A liquid phase process for the oligomerization of C
4
and C
5
isoolefins is disclosed in U.S. Pat. No. 5,003,124 wherein the reaction mixture is allowed to boil to remove the heat of reaction and a further dimerization is obtained in a reactive distillation column. U.S. Pat. No. 4,242,124 Smith discloses the reaction of isobutene with itself in a catalytic distillation column reactor to form diisobutene.
Brunelli, et al, in U.S. Pat. No. 5,510,555 disclose that the two isomers of diisobutene, 2,4,4-tri-methyl pentene and 2,4,4-tri-methyl-2-pentene when hydrogenated both yield 2,2,4 tri-methyl pentane which is the standard for octane measurement, i.e., RON=100 and MON=100.
Isooctane is not known to have been produced in a single step process of concurrent dimerization and hydrogenation heretofore.
SUMMARY OF THE INVENTION
Briefly the present invention comprises the concurrent dimerization of isobutene and the hydrogenation of the resultant diisobutene in a single distillation column reactor. Catalysts useful for the dimerization reaction include acidic cation exchange resins and zeolites. The hydrogenation catalysts are preferably Group VIII metals preferably deposited on carrier or support, such as an alumina, and include, among others, platinum, nickel, palladium and cobalt. The catalysts may be placed in the distillation column reactor in alternating layers or physically mixed. Alternatively bifunctional catalysts may be used, such as cation resins having palladium complexes deposited thereon.
The isobutene may be fed along with a hydrogen stream to a reaction distillation column at an effectuating hydrogen partial pressure of at least about 0.1 psia to less than 70 psia, such as less than 50 psia to a reactive distillation containing both a dimerization catalyst and a hydrogenation catalyst both of which are preferably components of a distillation structure. A portion of the diisobutene is selectively hydrogenated. Within the hydrogen partial pressures as defined no more hydrogen than necessary to maintain the catalyst and hydrogenate the olefinic compounds is employed, since the excess hydrogen is usually vented. In addition to the concurrent dimerization and hydrogenation there is also a concurrent fractionation of the reaction mixture within the reactive distillation zone.
The C
4
feed containing the isobutene is preferably maintained within the catalyst bed or beds. As in any distillation, the composition of a fraction within a section of the column, e.g., a catalyst bed can be controlled by adjusting the pressure in the column pressure, in so doing the isobutene is selectively dimerized and hydrogenated and the higher boiling C
8
product is fractionated downward from the catalyst bed. Some of the isobutene may be hydrogenated before it is dimerized and the lower boiling C
4
alkanes are fractionated upward out of the catalyst bed.
The term “reactive distillation” is used to describe the concurrent reaction and fractionation in a column. For the purposes of the present invention, the term “catalytic distillation” includes reactive distillation and any other process of concurrent reaction and fractional distillation in a column, i.e., a distillation column reactor, regardless of the designation applied thereto.
The catalyst beds as used in the present invention may be described as fixed, meaning positioned in a fixed area of the column and include expanded beds and ebulating beds of catalysts. The catalysts in the beds may all be the same or different so long as they carry out the functions of dimerization and hydrogenation as described. Catalysts prepared as distillation structures are particularly useful in the present invention.
REFERENCES:
patent: 3728415 (1973-04-01), Arganbright
patent: 3758626 (1973-09-01), Arganbright et al.
patent: 3960978 (1976-06-01), Givens et al.
patent: 4021502 (1977-05-01), Plank et al.
patent: 4150062 (1979-04-01), Garwood et al.
patent: 4211640 (1980-07-01), Garwood et al.
patent: 4227992 (1980-10-01), Garwood et al.
patent: 4242530 (1980-12-01), Smith, Jr.
patent: 4950834 (1990-08-01), Arganbright et al.
patent: 5003124 (1991-03-01), Smith, Jr. et al.
patent: 5321163 (1994-06-01), Hickey et al.
patent: 5510555 (1996-04-01), Brunelli et al.
patent: 5595634 (1997-01-01), Hearn et al.
patent: 5608133 (1997-03-01), Chang et al.
Gildert Gary R.
Loescher Mitchell E.
Catalytic Distillation Technologies
Dang Thuan D.
Johnson Kenneth H.
Knode Marian C.
LandOfFree
Catalytic distillation process for the production of C8 alkanes does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Catalytic distillation process for the production of C8 alkanes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Catalytic distillation process for the production of C8 alkanes will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2534375