Chemistry of hydrocarbon compounds – Plural serial diverse syntheses – Same catalyst – solvent – or component thereof used in both...
Patent
1985-12-16
1990-05-15
Pal, Asok
Chemistry of hydrocarbon compounds
Plural serial diverse syntheses
Same catalyst, solvent, or component thereof used in both...
585313, 585322, 585329, 585415, 585422, 585424, 585533, C07C 212
Patent
active
049259962
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a method of catalytically converting olefins into higher hydrocarbons. This invention more particularly relates to a method for converting feedstocks containing ethylene and C.sub.3 + olefins to higher hydrocarbons by contact with siliceous crystalline molecular sieves.
BACKGROUND ART
Conversion of various hydrocarbon fractions with acidic catalysts generally and more particularly with siliceous crystalline molecular sieves is well known in the art. The conversions for which such catalysts have been used include cracking, isomerization, hydrocracking, etc. Molecular sieves have also been used for the conversion of hydrocarbon feeds consisting essentially of C.sub.2 -C.sub.5 olefins, mixtures thereof, and mixtures thereof with paraffins to higher molecular weight products.
U.S. Pat. No. 3,325,465 teaches a process for polymerizing olefinic hydrocarbons over zeolites, the initially present cations of which have been partially exchanged with cations selected from the group consisting Co, Ni and rare earth cations. Ethylene polymerization at atmospheric pressure is described in Examples 3-8 of the patent. At column 6, lines 41-47, the patent teaches that use of atmospheric pressure is preferred, although pressures up to 1000 atmospheres may be used. Higher pressures are said to increase throughput but increase the risk of catalyst deactivation. Operating temperatures of 25.degree. to 400.degree. C. and space velocities of 50 to 1000 hr..sup.-1 VHSV (volume hourly space velocity), preferably less than 300 hr..sup.-1 VHSV, are taught. Hydrocarbon diluents such as paraffins and/or cycloparaffins may be present in the olefinic feedstock, but the patent does not indicate what effect such presence may have on selection of operating parameters for the process.
U.S. Pat. No. 3,760,024 teaches preparation of aromatic compounds by contacting C.sub.2 -C.sub.4 paraffins and/or olefins with a ZSM-5 type zeolite. Operating temperatures of 100.degree.-700.degree. C., operating pressures of 0-1000 psig (preferably 0-500 psig), and space velocities of 0.5-40 hr..sup.-1 WHSV (weight hourly space velocity) are taught. The particular combination of operating parameters employed is selected to produce a significant yield of liquid product from a given feedstock, which product is substantially aromatic in nature.
U.S. Pat. No. 3,827,968 discloses an aromatization process wherein the olefin content of a C.sub.2 -C.sub.5 olefin-containing feed is first oligomerized to produce higher molecular weight olefins over a ZSM-5 type zeolite and then contacting the liquid, higher molecular olefins with a zeolite catalyst in a second stage to produce aromatic liquids. The first step of the '968 process differs from the '024 patent in that less severe operating conditions are used to produce a product having a liquid portion consisting principally of C.sub.5 -C.sub.9 olefins. Attempting direct aromatization of certain feedstocks--especially those containing large amounts of paraffins--was apparently found to cause rapid catalyst aging and/or deactivation. Operating conditions employed in the first step of the '968 patent include temperatures of 290.degree.-450.degree. C., pressures up to 800 psig and 0.5-50 hr..sup.-1 WHSV. The first stage oligomerization effluent, in addition to olefinic liquids, contains a gas product consisting of a highly paraffinic C.sub.4 - stream. In addition, the second stage of the '968 process produces an effluent which may contain up to 50% C.sub.4 - paraffins. The C.sub.4 - paraffin streams are, according to the '968 patent, preferably recycled to a pyrolysis unit.
U.S. Pat. No. 3,960,978 discloses the conversion of gaseous C.sub.2 -C.sub.5 olefins, either alone or in admixture with paraffins, to a gasoline fraction having no more than about 20 wt. % aromatics by contacting the olefin feed with a ZSM-5 type zeolite having a controlled acid activity (i.e., alpha value) of about 0.1-120. Other oligomerization conditions include temperatures of 260.degree.-480.degree. C. (p
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Atlantic Richfield Company
Larson Craig E.
Pal Asok
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