Stereospecific Isomerization of Butene-1 to Butene-2 over SiO2-Al2O3 Catalyst

Lucchesi, P. J.; Baeder, D. L.; Longwell, John P.

doi:10.1021/ja01522a019

Cited by 50 publications

(22 citation statements)

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“…The isomerization of olefins was studied in a number of publications during the past (18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35). Double-bond and cis-trans isomerization, as well as the skeletal rearrangement of these substances, were in the focus of interest (e.g., (18,19,33)).…”

Section: Introductionmentioning

confidence: 99%

Dehydrogenation of Light Alkanes over Zeolites

Narbeshuber

Brait

Seshan

et al. 1997

Journal of Catalysis

114

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The conversion of light paraffins to olefins and the secondary reactions of the unsaturated compounds were investigated on H-ZSM5 and H-Y zeolites between 733 and 823 K. Steady stateand transient response-isotope tracing studies revealed that two mechanisms of dehydrogenation are operative. The main pathway is represented by monomolecular, protolytic dehydrogenation. This reaction contributes most to steady state olefin production. Additionally, at the initial stages of the reaction, extra framework aluminum moieties are speculated to participate in high dehydrogenation activity. This pathway is blocked at later stages of the reaction by product (hydrogen) inhibition. The intrinsic rates of protolytic dehydrogenation and olefin desorption range in the same order of magnitude. At high protolytic dehydrogenation rates, olefin desorption represents the rate determining step. Depending on the process conditions, olefins undergo secondary cracking, oligomerization, or isomerization. The latter proceeds via intramolecular rearrangement, possibly via a cyclopropylcarbenium ion at high temperatures and low conversions. At reaction conditions where bimolecular cracking prevails, isomerization is concluded to occur via secondary cracking of di-or oligomers.

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Section: Introductionmentioning

confidence: 99%

Dehydrogenation of Light Alkanes over Zeolites

Narbeshuber

Brait

Seshan

et al. 1997

Journal of Catalysis

114

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“…This implies that the methyl group shift occurs on the surface, probably by an ionic mechanism (12,13).…”

Section: Reactionsmentioning

confidence: 98%

The Thermal Cis–trans Isomerization and Decomposition of Methyl Crotonate

Butler¹,

Small²

1963

Can. J. Chem.

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“…Several kinetic studies have been carried out on inetallic catalysts and the mechanism of olefill isomerization has been discussed in conjunction with the mechanism of hydrogenation (2-3). On the other hand, relatively few kinetic studies of olefin iso~nerizations on oxide catalysts are avaiIable (12,13,18,21).Carbonium ions and carbanions have been postulated by many investigators as intermediates in the catalytic reactions of olefins ancl have been also recently invoked to explain the stereoselectivity in the catalytic isomerization of butenes (6, 15). I t is felt, ]lowever, that further lcinetic studies of these reactions, on catalytic materials of various types, are necessary, and the present work has, therefore, been carried out with the object of obtaining kinetic information on butene isomerization on a chromia-alumina catalyst.…”

mentioning

confidence: 99%

“…I t is well known that the presence of hydrogen is necessary for the olefin isomerization on some ~netallic catalysts (1-G), while the reaction occurs in the absence of hydrogen on metal oxide, alkali, and acid catalysts (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). Several kinetic studies have been carried out on inetallic catalysts and the mechanism of olefill isomerization has been discussed in conjunction with the mechanism of hydrogenation (2-3).…”

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confidence: 99%

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KINETIC STUDY OF THE ISOMERIZATION OF n-BUTENES ON CHROMIA–ALUMINA

Amenomiya¹,

Cvetanović²

1962

Can. J. Chem.

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hZIutnal i~lterconversions of the three ti-butenes on a chromia-alumina catalyst have bccn st~~diccl in a t e m p c r a t~~r e range between 210 and 2G0° C and in a pressure rangc from about 10 to about 100 mnl. Depenclence of initial rates on the initial pressures of the reactants was clctermi~~ed expcrimei~tallp. The initial rates of isolnerization could be, in each case, expressed ernpiricall); b?. a rate ecluation conforming to the Langmuir-I-linsl~el\\~ood form~rla. It was possible to explain thc experimental results by assunling the existence of three din'erent aclsorbecl species for the thrcc 71-butene iso~~lers and their surface intercor~versions as the rate-cleterrninir~g step.Catalytic isomerization of butenes has been extensively investigated in attempts to contribute to the understanding of the mechanism of the catalytic isomerization of olefins. I t is well known that the presence of hydrogen is necessary for the olefin isomerization on some ~netallic catalysts (1-G), while the reaction occurs in the absence of hydrogen on metal oxide, alkali, and acid catalysts (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). Several kinetic studies have been carried out on inetallic catalysts and the mechanism of olefill isomerization has been discussed in conjunction with the mechanism of hydrogenation (2-3). On the other hand, relatively few kinetic studies of olefin iso~nerizations on oxide catalysts are avaiIable (12,13,18,21).Carbonium ions and carbanions have been postulated by many investigators as intermediates in the catalytic reactions of olefins ancl have been also recently invoked to explain the stereoselectivity in the catalytic isomerization of butenes (6, 15). I t is felt, ]lowever, that further lcinetic studies of these reactions, on catalytic materials of various types, are necessary, and the present work has, therefore, been carried out with the object of obtaining kinetic information on butene isomerization on a chromia-alumina catalyst. This catalyst is used commercially as a dehydl-o-isomerization catalyst. CatalystChrornia-alumina catalyst was prepared by mixing and grinding a l u m i n~~m hydroxide and chrorni~~m hydroxide, both of which were spearately precipitated by adding ammonium hydroxide to the solutions of the respective nitrates. The composition of the cataIyst was about 20% Cr?Os and 80% A1?03 by weight, as calculated from the loss on ignition of the two hydroxides. The catalyst was heated a t 500' C for 1 hour, a;lcl crushecl into pieces of convenient size. The sarne catalyst sample, weighing 0.0038 g, was used in all kinetic measurements. The surface area of the catalyst, determined by the B.E.T. method with nitrogen, -was 100.5 m2/g. Research grade butenes of Phillips Petroleum Co. were used as reactants. They \\.ere twice condensed in liouid nitrocen tram follo\ved bv evacuation, and were kept in a 3-1. reservoir. The irnpuritics in 1-butene -and cis-butene were negligibly small, but tra7bs-butene contained a small amount of cis-butenc, which \\.as subtracted ...

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Stereospecific Isomerization of Butene-1 to Butene-2 over SiO₂-Al₂O₃ Catalyst

Cited by 50 publications

References 0 publications

Dehydrogenation of Light Alkanes over Zeolites

Dehydrogenation of Light Alkanes over Zeolites

The Thermal Cis–trans Isomerization and Decomposition of Methyl Crotonate

KINETIC STUDY OF THE ISOMERIZATION OF n-BUTENES ON CHROMIA–ALUMINA

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