Chemistry of hydrocarbon compounds – Special chemical considerations – Opening of hydrocarbon ring
Reexamination Certificate
1998-04-27
2001-05-22
Griffin, Walter D. (Department: 1764)
Chemistry of hydrocarbon compounds
Special chemical considerations
Opening of hydrocarbon ring
C585S700000, C585S750000
Reexamination Certificate
active
06235962
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to a process and catalyst for ring opening of cyclic compounds. More particularly, the invention concerns metal-supported oxide-based catalysts and a process for ring opening of cyclic compounds including derivatives of cyclopentane, cyclohexane, decaline, indane (indene), benzene, and naphthalene being present in diesel fuel in presence of hydrogen to linear or branched paraffinic molecules.
2. Description of the Related Art
One of the approaches to the improvement of the certain number of diesel fuel is to increase the content of paraffinic compounds with linear chains in the diesel fuel. The content of non-cyclic paraffins in the hydrocarbon mixture can be increased by carrying out ring opening of cycloparaffins formed upon hydrogenation of aromatic compounds present in the fuel.
Commercially available catalytic systems based on 1% Pt/H-Beta zeolite are disclosed in U.S. Pat. No. 5,382,730. The described catalysts exhibit rather high activity in ring opening of C
6
cyclic compounds and are used in combination with isomerization catalysts to improve quality of a C
5
-C
6
downstream feed. In this case, however, a 1:3 mixture of normal and isoparaffins was formed at conversion rates of ~80% at 230-270° C. under high-pressure conditions. Another catalyst is proposed in U.S. Pat. No. 5,382,731 for ring opening of C
6
cyclic compounds comprising a 1% Pt/WO
3
/ZrO
2
system. The performance of this catalyst is similar to that of Pt/H-Beta zeolite, at slightly different reaction conditions.
Only a very limited number of prior art publications is available, which are related to decalin conversion on zeolite and oxide catalysts. In most of these publications decalin cracking is studied, which leads to more than 100 products in the C1-C10 range. Decalin conversion has also been studied from the viewpoint of its cis-trans isomerization. There is no available reported data on decalin conversion on oxide catalysts.
SUMMARY OF THE INVENTION
The general object of this invention is to provide efficient heterogeneous metal supported catalysts based on various oxide carriers and a process for ring opening of cyclic compounds in the presence of hydrogen by use of the catalysts.
Various types of oxides, hydroxides or mixed oxides and hydroxides can be used as supports for active metal components in ring opening of cyclic organic compounds.
The carriers for the ring opening catalysts are the commercial forms of alumina, silica, zirconia, and mixtures thereof. The oxides are modified with II-VI Group metals, such as tungsten, molybdenum, lanthanum, other rare earth metals, etc.
Catalytically active metals supported on the appropriate carriers are noble and transition metals such as platinum, palladium, rhodium, rhenium, iridium, ruthenium, nickel, cobalt or combinations thereof. The metal loading in the catalyst may range from 0.1 to 10 wt %.
In accordance with the above finding, the present invention provides a catalyst active in ring opening of cyclic organic compounds comprising on a carrier of alumina, silica, zirconia and mixtures thereof, preferably from 0.1 to 10 percent by weight of a catalytic active metal selected from platinum, palladium, rhodium, rhenium, iridium, ruthenium, nickel, cobalt and mixtures or combinations thereof and from 0.01 to 20 percent by weight of a metal modifier selected from tungsten, molybdenum and rare earth metals (Sc,4, and La to Lu inclusive).
The invention furthermore provides a process for the ring opening of cyclic organic compounds by contacting the compounds in presence of hydrogen with a catalyst comprising a carrier of alumina, silica, zirconia and mixtures thereof from 0.1 to 10 percent by weight of a catalytic active metal selected from platinum, palladium, rhodium, rhenium, iridium, ruthenium, nickel, cobalt and mixtures or combinations thereof and from 0.01 to 20 percent by weight of a metal modifier selected from tungsten, molybdenum, lanthanum and rare earth metals.
When operating the process of the invention, hydrogen or a mixture of hydrogen with an inert gas is used as a reducing agent.
Hydrocarbons or mixtures thereof are introduced in a flow-type high-pressure reactor as a mixture with hydrogen or with a mixture of hydrogen and an inert gas.
Convenient process conditions are a hydrogen- to-hydrocarbon ratio ranging from 1:1 to 1:50, more preferably from 1:5 to 1:20; a liquid hourly space velocity ranging from 0.1 to 10, more preferably, from 0.5 to 2; and a total pressure from 1 to 100 atm, more preferably from 20 to 50 atm. The reaction is preferably carried out at a temperature from 450 to 670° K.
The products evolving from the process comprise typically a mixture of gas products and liquid products, including paraffinic linear or branched hydrocarbons, cyclic compounds (both naphthenes and aromatics).
In order to further illustrate the present invention and the advantages thereof, the following specific examples are given below.
In the Examples, the following parameters (in percent) are used: C=percentage of conversion, S=selectivity, Y=yield based on the product passed=C×S.
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patent: 5382731 (1995-01-01), Chang et al.
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Griffin Walter D.
Haldor Topsoe A/S
Nguyen Tam M.
Ostrolenk Faber Gerb & Soffen, LLP
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