Catalytic Cracking of Pure Hydrocarbons

Voge, H. H.; Good, G. M.; Greensfelder, B. S.

doi:10.1021/ie50442a018

Cited by 34 publications

(22 citation statements)

References 4 publications

(6 reference statements)

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“…Once formed, propylene does not convert by hydrogen transfer to propane as easily as butenes because of the low reactivity of the propyl carbenium ion. 5 The advantage of the ZSM5 additive relative to Y-zeolite is its selectivity to crack naphtha olefins to C3 rather than C4.…”

Section: ■ State Of the Artmentioning

confidence: 99%

Naphtha Cracking Kinetics and Process Chemistry on Y and ZSM5 Type Catalysts

Longstaff¹

2019

Energy Fuels

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A deeper understanding of naphtha catalytic cracking is required for on-purpose propylene production in downflow HS-FCC. A study was conducted wherein olefinic and paraffinic naphthas were cracked in a MAT (microactivity test) reactor over various blends of Y- and ZSM5-based catalysts. Reaction kinetics was tracked in order to gain insights into the process chemistry of naphtha catalytic cracking. It was found that olefins rapidly crack in olefinic naphthas while the other components crack at a much slower rate. The ultimate conversion of paraffinic naphtha is approximately equal to the total paraffin content. Naphthenes can either crack or convert to aromatics depending on temperature and ZSM5 content in the mixture. The formation of dry gas (H2, C1, and ethane) is due to carbonium-ion cracking and not thermal cracking. The relative important of carbonium- or carbenium-ion cracking is determined by process conditions and by catalyst composition.

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Section: ■ State Of the Artmentioning

confidence: 99%

Naphtha Cracking Kinetics and Process Chemistry on Y and ZSM5 Type Catalysts

Longstaff¹

2019

Energy Fuels

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“…The aromatics are approximately equally distributed over the three boiling ranges up to 162°, 152°to 174°, and above 174°C. (10).…”

Section: Of Butylene Into Aromaticsmentioning

confidence: 99%

Conversion of Butylene into Aromatics

Weizmann¹,

Henri²,

Bergmann³

1951

Ind. Eng. Chem.

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“…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).…”

mentioning

confidence: 99%

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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Catalytic Cracking of Pure Hydrocarbons

Cited by 34 publications

References 4 publications

Naphtha Cracking Kinetics and Process Chemistry on Y and ZSM5 Type Catalysts

Naphtha Cracking Kinetics and Process Chemistry on Y and ZSM5 Type Catalysts

Conversion of Butylene into Aromatics

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

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