摘要:
A process for preparing C5/C6-olefins from an olefinic starting stream comprising C4-hydrocarbons comprises a) carrying out a metathesis reaction in the presence of a metathesis catalyst so as to convert the 1-butene, 2-butene and isobutene present in the starting stream into a mixture of C2-C6-olefins and butanes, b) firstly fractioning the resulting product stream by distillation to give a low boiler fraction A comprising C2-C4-olefins and butanes or C2-C3-olefins, which is discharged, and a high boiler fraction comprising C4-C8-olefins and butanes, c) fractioning the high boiler fraction from b) by distillation to give a low boiler fraction B comprising butenes and butanes, an intermediate boiler fraction C comprising pentene and methylbutene and a high boiler fraction D comprising hexane and methylpentene, d) where all or part of the fraction B and/or C are recirculated to the process step a) and the fraction D is discharged as product.
摘要:
A process for improved yields of heavier olefins from a substantially narrow range of lighter hydrocarbon feed stock containing olefins in a reaction distillation column comprising feeding a narrow range of hydrocarbon feed stock containing olefin into a reaction distillation column at a point between its bottom and top, contacting the olefins at the point of feed with a disproportionation catalyst in alternating arrangement with an isomerization catalyst or a mixture thereof and keeping the reaction mixture in a state of vapor-liquid equilibrium for concentrating the lighter reaction products in the vapor phase and the heavier reaction products in the liquid phase by maintaining a controlled pressure and temperature profile in the reactive distillation column and for reactively creating the desired heavier molecular weight olefins over the catalysts and collecting it as bottoms product and removing the lighter molecular weight olefins overhead from the top of the reactive distillation column.
摘要:
A composition and method for the catalytic conversion of a racemic mixture of dienes to a cyclic olefin by a ring-closing metathesis (RCM) reaction are disclosed. The composition, a transition metal complex with an M═C reaction site, contains a bidentate dialkoxide of at least 80% optical purity. Because the M═C reaction site is of a sufficient shape specificity, conferred in part by the dialkoxide of sufficient rigidity and a M═N—R1 site, reacting the composition with a mixture of two enantiomeric dienes results in an olefin metathesis product that has at least a 50% enantiomeric excess of one enantiomer in the mixture. A method is also provided for reacting a composition with a racemic diene mixture to generate a metathesis product that has an enantiomeric excess of at least 50%. Methods are also provided for catalytic enantioselective desymmetrization. One method involves an olefin metathesis reaction with a molecular substrate having a plane of symmetry to form a product free of a plane of symmetry. Another method provides a desymmetrization reaction to occur in the absence of solvent. A method for producing quaternary carbon centers through a desymmetrization reaction is also described.
摘要:
This invention pertains to a continuous catalytic process, for example, for the metathesis of olefins that uses a catalyst circulating in a moving bed in at least one reaction zone operating in the liquid phase and in a regenerator, with a lift to transfer the deactivated catalyst emerging from the reaction zone to the regenerator, whereby said process is characterized by the fact that the transfer is accomplished by a gas that does not react with the catalyst and with the stripping off of at least a portion of the organic matter that is adsorbed on the deactivated catalyst.
摘要:
Propene and, if desired, 1-butene are prepared by first reacting 1-butene and 2-butene to give propene and 2-pentene in the presence of a metathesis catalyst containing at least one compound of a metal of transition group VIb, VIIb or VIII of the Periodic Table of the Elements. The propene and 2-pentene formed are subsequently separated, and the 2-pentene is then reacted to give propene and 1-butene in the presence of a metathesis catalyst containing at least one compound of a metal of transition group VIb, VIIb or VIII. The propene and 1-butene formed are subsequently separated, and at least some of the 1-butene is discharged or at least partly isomerized to give 2-butene in the presence of an isomerization catalyst. Undischarged 1-butene and the 2-butene formed are subsequently returned to the initial reaction step, together with that part of the C4 fraction which was not reacted in the initial reaction step.
摘要:
The present invention relates to a process for preparing propene by metathesis of olefins. The process comprises preparing propene by a) in a first reactor (R1), reacting 1-butene and 2-butene to give propene and 2-pentene in the presence of a metathesis catalyst comprising at least one compound of a metal of transition group VIb, VIIb, or VIII of the Periodic Table of elements, b) subsequently separating the propene, unreacted raffinate II, and 2-pentene formed in a) in a distillation column (D1), c) subsequently reacting the 2-pentene of b) with ethene to give propene and 1-butene in a reactor (R2) in the presence of a metathesis catalyst comprising at least one compound of a metal of transition group VIb, VIIb, or VIII of the Periodic Table of Elements, d) subsequently separating the propene and 1-butene formed in c), e) subsequently returning the 1-butene formed in d) to step a) and f) wherein unreacted raffinate II is taken off at the middle off take of column D1 in b) and partly returned to step a).