Process for the production of high-octane hydrocarbon compounds by the selective dimerization of isobutene contained in a stream which also contains C5 hydrocarbons
AssigneeSnamprogetti S.p.A.
InventorsMarco Di Girolamo, Domenico Sanfilippo, Massimo Conte
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Abstract
A process is described for the production of high-octane hydrocarbon compounds by means of the selective dimerization of isobutene, in the presence of C5 hydrocarbons and oxygenated compounds (branched alcohols or alternatively blends of linear or branched alcohols and alkyl ethers) characterized in that it utilizes a catalytic distillation as second reaction step.
Claims32
A process for the production of high-octane hydrocarbon compounds comprising a selective dimerization of isobutene comprised in a stream also comprising C5 hydrocarbons, wherein:
- the selective dimerization is carried out with acid catalysts in two distinct steps wherein the first step consists of contacting the stream with one or more fixed bed reactors and the second step consists of catalytically distilling the stream;
- wherein the selective dimerization is carried out in the presence of one or more oxygenated products selected from a branched alcohol alone or in a blend with linear alcohols and alkyl ethers, wherein the branched alcohol forms an azeotropic mixture with the C5 hydrocarbons, in such a quantity as to have in the feeding, in the case of the presence of a branched alcohol alone, a molar ratio of oxygenated product/isobutene higher than 0.005, in the case of the presence of a branched alcohol in a blend, a molar ratio of oxygenated product/isobutene higher than 0.01;
- and
- a C5/branched alcohol azeotropic separation step is carried out.
A process for producing a high-octane hydrocarbon composition, comprising:
- dimerizing isobutene present in a hydrocarbon stream comprising one or more C5 hydrocarbons by contacting the hydrocarbon stream with one or more acid catalysts in one or more fixed bed reactors to form a dimerized hydrocarbon stream comprising one or more C5/branched alcohol azeotropes;
- then
- catalytically distilling the dimerized hydrocarbon stream to form a catalytically distilled hydrocarbon stream;
- then
- separating a C5/branched alcohol azeotrope from the catalytically distilled hydrocarbon stream;
- wherein the hydrocarbon stream is dimerized in the presence of one or more oxygenated products selected from the group consisting of a branched alcohol, a blend of a branched alcohol with one or more linear alcohols, a blend of a branched alcohol with one or more alkyl ethers, and a blend of a branched alcohol with one or more linear alcohols and one or more alkyl ethers,
- wherein the hydrocarbon stream comprises the isobutene and the oxygenated product in an oxygenated product/isobutene molar ratio of greater than 0.005 when the oxygenated product consists of a branched alcohol;
- or the hydrocarbon stream comprises the isobutene and the oxygenated product in an oxygenated product/isobutene molar ratio of greater than 0.01 when the oxygenated product is a blend of the branched alcohol with one or more of the linear alcohol and the alkyl ether.
Dependencies are inferred from the claim text.