Oxidative Dehydrogenation Of Ethylbenzene Research Articles

Base properties of modified γ-alumina

The basicity of binary oxide catalysts obtained on γ-Al 2O 3 support was studied with Fe 2O 3, Cr 2O 3, NiO, MoO 3 and MgO as modifiers, introduced in amounts up to 7 wt.- % by coprecipitation. Their activity in the decomposition of diacetone alcohol to acetone and the extent of coke deposition on their surfaces in the oxidative dehydrogenation of ethylbenzene were determined. It was found that modification of γ-Al 2O 3 with small amounts of oxides considerably changes its base properties.

ChemInform Abstract: Oxidative Dehydrogenation of Ethylbenzene over Lanthanide Oxide‐Promoted Catalysts.

Abstract The oxidative dehydrogenation of ethylbenzene (EB) to styrene (S) has been studied over molybdena-alumina promoted with lanthana, ceria, praseodymia or neodymia, as well as the unpromoted catalyst Reaction variables were: temperature, 450–550°C; space velocity, 360–1600 h−1; mole ratio of EB:02 = 1.7-3.0. There is an induction period of 2–3 hours at 500°C, during which conversion and selectivity increase to steady-state values which remain constant during 18 hours on stream. Air regeneration of the used catalyst results in a renewed induction period but identical steady-state values of conversion and selectivity. Pre-reduction of fresh catalyst does not eliminate the induction period and, surprisingly, steady-state conversion is lower for pre-reduced than for unreduced catalyst. The lanthanide oxide-promoted catalysts show 2–6% higher conversion, and 1–4% higher selectivity, than the unpromoted catalyst. Of the lanthanide oxides tested, praseodymia exhibits the highest promoting effect; it is also the most labile of these oxides in redox reactions. In the absence of oxygen (i.e., in non-oxidative dehydrogenation of ethylbenzene), conversions are substantially lower and the lanthanide oxides show no promoter effect. Coke is deposited during reaction of EB but does not result in deactivation or loss of surface area.

ChemInform Abstract: Catalytic Properties of Rhenium Containing Oxide Systems in the Oxidative Dehydrogenation of Ethylbenzene and Cyclohexane.

ChemInform Abstract: Catalytic Properties of Rhenium Containing Oxide Systems in the Oxidative Dehydrogenation of Ethylbenzene and Cyclohexane.

Oxidative dehydrogenation of ethylbenzene over lanthanide oxide-promoted catalysts

The oxidative dehydrogenation of ethylbenzene (EB) to styrene (S) has been studied over molybdena-alumina promoted with lanthana, ceria, praseodymia or neodymia, as well as the unpromoted catalyst Reaction variables were: temperature, 450–550°C; space velocity, 360–1600 h −1; mole ratio of EB:0 2 = 1.7-3.0. There is an induction period of 2–3 hours at 500°C, during which conversion and selectivity increase to steady-state values which remain constant during 18 hours on stream. Air regeneration of the used catalyst results in a renewed induction period but identical steady-state values of conversion and selectivity. Pre-reduction of fresh catalyst does not eliminate the induction period and, surprisingly, steady-state conversion is lower for pre-reduced than for unreduced catalyst. The lanthanide oxide-promoted catalysts show 2–6% higher conversion, and 1–4% higher selectivity, than the unpromoted catalyst. Of the lanthanide oxides tested, praseodymia exhibits the highest promoting effect; it is also the most labile of these oxides in redox reactions. In the absence of oxygen (i.e., in non-oxidative dehydrogenation of ethylbenzene), conversions are substantially lower and the lanthanide oxides show no promoter effect. Coke is deposited during reaction of EB but does not result in deactivation or loss of surface area.

Catalytic properties of rhenium oxide systems in the oxidative dehydrogenation of ethylbenzene and cyclohexane

1. The oxidative dehydrogenation of ethylbenzene and cyclohexane on rhenium oxide catalysts proceeds 10–30 times more rapidly than simple dehydrogenation. 2. Rhenium oxide and the oxidative condensation products (OCP) act additively in the oxidative dehydrogenation of ethylbenzene to increase the conversion of this hydrocarbon and the yield of styrene. 3. The addition of rhenium oxide to vanadium-magnesium systems increases their activity and selectivity in the oxidative dehydrogenation of ethylbenzene and suppresses extensive oxidative reactions.

Relationship between the acidity of nickel phosphate (NiP) catalysts and their activity in ethylbenzene oxydehydrogenation

A nickel phosphate catalyst was prepared from nickel nitrate and ammonium phosphate solutions by a precipitation method. The activities of the catalyst samples were examined in a flow reactor at various time intervals from the start of an ethylbenzene oxidative dehydrogenation reaction. Total and Brønsted acid surface sites concentration on the catalyst were determined from the adsorption of pyridine and 2,4,6-trimethylpyridine respectively, at those intervals. The relationship between styrene yield and catalyst surface acidity has been discussed. Styrene yield proved to be well correlated only with the concentration of Lewis type acid sites on the surface of the catalyst samples. An increase in surface proton concentration, though relevant to acceleration of “active coke” formation on the catalyst surface as a consequence of side reactions accompanying the oxydehydrogenation, caused a decrease in the styrene yield.

Mechanism of byproduct formation in oxidative dehydrogenation of ethylbenzene to styrene on magnesium ferrite-containing catalyst

It has been shown by application of the kinetic isotope method that in the oxidative dehydrogenation of ethylbenzene to styrene on a magnesium ferrite catalyst, benzene and toluene are formed from ethylbenzene and also from styrene. Carbon dioxide appears mainly as a result of exhaustive oxidation of the side chain of the aromatic hydrocarbon.

炭化水素の気相接触酸化

The background and main points of recent works on vapor phase oxidation of C3, C4 olefins and ethylbenzene with multi-component oxide catalysts are described.Fe-As and Mo-Ce (or Al, Ba, Sr) -As oxides were found to have high catalytic activity for producing acrolein by vapor phase oxidation of propylene with air. The activity of Fe-As oxide decreased with reaction time because of the escape of As component, especially in the reaction at high temperature, such as oxidation of i-butylene to methacrolein.This defect was eliminated and initial activity was kept by adding Li component to Fe-As system. With Fe-Li-As oxide of atomic ratio= 1 : 2 : 2.5 1 : 3 : 3, high yield of methacrolein was obtained from i-butylene at the temperature of 470°C.By means of searching direct oxidation of the olefins with Fe-As5+ oxide systems and formation of As5+ in As3+ oxide systems and studying the structure of catalyst, following conclusions were obtained.The catalytic oxidation of α-CH bond to aldehyde is carried out by a cycle consisting of two reactions : 2 As5+ oxide + CH2 = CR-CH3 → 2 As3+oxide CH2= CR-CHO and2 As 3+oxide + O2 → 2 As5+oxide (R : H or -CH 3).The former reaction, remarkably promoted by the Fe component in the catalyst, is always accompanied with formation of CO2, but proceeds more dominantly when As5+ concentration is high. Two structures of -Fe-O-As- and -Li -O-As- were observed in Fe-Li-As oxide catalyst; the former is more easily reduced with olefin than the latter.-Fe-O-As- structure has at least two kinds of active site. Unsaturated aldehyde forms on one site and CO2 on another site. Li-O-As structure is stable and instrumental in preventing the escape of As component into vapor phase.The activity of Mo-X-As (X : alkaline earth metal) oxide catalyst for oxidative dehydrogenation of 1-butene was studied in connection of its preparation and physical property.A Si-Ce-Sb oxide catalyst of new type showed relatively high activity for styrene formation by oxidative dehydrogenation of ethylbenzene.

Oxidative dehydrogenation of ethylbenzene on vanadium-magnesium oxide catalysts

Summary 1. Oxidative dehydrogenation of ethylbenzene to styrene at 470°–500°C was studied on a vanadium-magnesium oxide catalyst: at an ethylbenzene s.v. of 0·35 to 1·2 hr−1 and ratios of ethylbenzene: oxygen:steam of 1:0·8 to 1·3:7 to 20. Styrene yield reached 74%, with a process selectivity of 90%. 2. The catalyst showed a high operating stability during 5000 hr without regeneration. 3. The following is recommended for simulating an industrial reactor: ethylbenzene : O2:H2O ratio of 1:1:7, C8 s.v. = 0·35 hr−1 at 470°–490°C.

A mechanistic study on vapor-phase catalytic oxidative dehydrogenation of ethylbenzene with carbonyl sulfide

A mechanistic study on vapor-phase catalytic oxidative dehydrogenation of ethylbenzene with carbonyl sulfide

Kinetics of ethylbenzene oxidative dehydrogenation to styrene over a vanadia/magnesia catalyst

Kinetics of vapor-phase ethylbenzene oxidative dehydrocenation have been studied at 420 to 550°C in a aradientless reactor in the presence of a vanadia/maanesiacatalyst. Kinetic equations have been obtained for this reaction in the directionof styrene and CO 2 formation which considers the effect of the reaction medium onthe surface state of the catalyst. A process scheme is proposed. This schemesuggests that dehydrogenation involves the interaction of adsorbed ethylbenzenewith lattice oxygen whereas the ion-radicals of oxygen adsorbed on the catalyst surface are active in the total oxidation.

Catalytic properties of modified silica gels in oxidative dehydrogenation of ethylbenzene

According to [i], oxides of silicon and alkaline earth metals exhibit low activity in oxidative dehydrogenation of alkylaromatic hydrocarbons. We observed that the activity of catalysts in oxidative dehydrogenation of ethylbenzene increased sharply when small amounts of calcium or strontium oxides were introduced into the composition of macroporous silica gel. A similar effect was also observed when silica gel was modified with magnesium, but in this case the maximum yield of styrene was attained at higher concentrations of magnesium oxide. The obtained results are shown in Fig. I, from which it is evident that the yield of styrene passed through a maximum, depending on the concentration of alkaline-earth metals. With decreasing ionic radius of the cations, the maximums became broader and shifted toward higher concentrations. The decrease of the catalysts' activity when large amounts of the oxides were introduced was probably due to the formation of highly basic centers, which drove the reaction toward exhaustive oxidation and thus lowered the selectivity of the reaction with respect to styrene.

Condensation during oxidative dehydrogenation of ethylbenzene with oxygen and sulphur dioxide: A. Ye. Lisovskii, Z. A. Talybova, A. Ye. Portyanskii, A. M. Musayev and T. G. Alkhazov, Neftekhimiya 23, No. 5, 622–627, 1983

Condensation during oxidative dehydrogenation of ethylbenzene with oxygen and sulphur dioxide: A. Ye. Lisovskii, Z. A. Talybova, A. Ye. Portyanskii, A. M. Musayev and T. G. Alkhazov, Neftekhimiya 23, No. 5, 622–627, 1983

Effect of products of oxidative condensation of alumina activity in oxidative dehydrogenation of ethylbenzene: A. Ye. Lisovskii, A. I. Kozharov and T. G. Alkharov, Neftekhimiya 23, No. 1, 45–47, 1983

Effect of products of oxidative condensation of alumina activity in oxidative dehydrogenation of ethylbenzene: A. Ye. Lisovskii, A. I. Kozharov and T. G. Alkharov, Neftekhimiya 23, No. 1, 45–47, 1983

ChemInform Abstract: Oxidative Dehydrogenation of Ethylbenzene. Part 2. Catalytic Activity and Acid and Base Properties of Na‐SiO2 · Al2O3. Part 3. Mechanism for Styrene Formation.

ChemInform Abstract: Oxidative Dehydrogenation of Ethylbenzene. Part 2. Catalytic Activity and Acid and Base Properties of Na‐SiO₂ · Al₂O₃. Part 3. Mechanism for Styrene Formation.

HETEROGENEOUS–HOMOGENEOUS MECHANISM FOR VAPOR-PHASE CATALYTIC OXIDATIVE DEHYDROGENATION OF ETHYLBENZENE BY CARBONYL SULFIDE

Abstract A mechanistic study on vapor-phase oxidative dehydrogenation of ethylbenzene to styrene by COS over SiO2,Al2O3,MgO,and TiO2 catalysts has been carried out. The results obtained indicate that the sulfur evolved by the heterogeneous catalytic decomposition of COS dehydrogenated ethylbenzene in the homogeneous phase.

ChemInform Abstract: STUDY OF THE OXIDATIVE DEHYDROGENATION OF ETHYLBENZENE. I. CATALYTIC BEHAVIOR R OF TIN(IV) OXIDE‐PHOSPHORUS(V) OXIDE

Chemischer InformationsdienstVolume 13, Issue 5 Preparative Organic Chemistry ChemInform Abstract: STUDY OF THE OXIDATIVE DEHYDROGENATION OF ETHYLBENZENE. I. CATALYTIC BEHAVIOR R OF TIN(IV) OXIDE-PHOSPHORUS(V) OXIDE Y. MURAKAMI, Y. MURAKAMISearch for more papers by this authorK. IWAYAMA, K. IWAYAMASearch for more papers by this authorH. UCHIDA, H. UCHIDASearch for more papers by this authorT. HATTORI, T. HATTORISearch for more papers by this authorT. TAGAWA, T. TAGAWASearch for more papers by this author Y. MURAKAMI, Y. MURAKAMISearch for more papers by this authorK. IWAYAMA, K. IWAYAMASearch for more papers by this authorH. UCHIDA, H. UCHIDASearch for more papers by this authorT. HATTORI, T. HATTORISearch for more papers by this authorT. TAGAWA, T. TAGAWASearch for more papers by this author First published: February 2, 1982 https://doi.org/10.1002/chin.198205082Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume13, Issue5February 2, 1982 RelatedInformation

ChemInform Abstract: THE NATURE AND CATALYTIC INFLUENCE OF COKE FORMED ON ALUMINA: OXIDATIVE DEHYDROGENATION OF ETHYLBENZENE

Chemischer InformationsdienstVolume 12, Issue 29 Preparative Organic Chemistry ChemInform Abstract: THE NATURE AND CATALYTIC INFLUENCE OF COKE FORMED ON ALUMINA: OXIDATIVE DEHYDROGENATION OF ETHYLBENZENE R. FIEDOROW, R. FIEDOROWSearch for more papers by this authorW. PRZYSTAJKO, W. PRZYSTAJKOSearch for more papers by this authorM. SOPA, M. SOPASearch for more papers by this authorI. G. DALLA LANA, I. G. DALLA LANASearch for more papers by this author R. FIEDOROW, R. FIEDOROWSearch for more papers by this authorW. PRZYSTAJKO, W. PRZYSTAJKOSearch for more papers by this authorM. SOPA, M. SOPASearch for more papers by this authorI. G. DALLA LANA, I. G. DALLA LANASearch for more papers by this author First published: July 21, 1981 https://doi.org/10.1002/chin.198129165AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume12, Issue29July 21, 1981 RelatedInformation

Oxidative dehydrogenation of ethylbenzene over modified palladium catalysts

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOxidative dehydrogenation of ethylbenzene over modified palladium catalystsKaoru Fujimoto and Taiseki KunugiCite this: Ind. Eng. Chem. Prod. Res. Dev. 1981, 20, 2, 319–323Publication Date (Print):June 1, 1981Publication History Published online1 May 2002Published inissue 1 June 1981https://doi.org/10.1021/i300002a017RIGHTS & PERMISSIONSArticle Views172Altmetric-Citations8LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (556 KB) Get e-Alerts

The nature and catalytic influence of coke formed on alumina: Oxidative dehydrogenation of ethylbenzene

Catalytic properties of alumina doped with 0.1 to 1.0 wt% NaOH, as well as that of pure alumina, were studied for the oxidative dehydrogenation of ethylbenzene and for some acid-catalyzed model reactions. The largest contribution to the formation of coke catalytically active for styrene formation was found to come from sites of moderate and weak acid strengths. Stronger acid centers produce cokes lower in hydrogen content, whereas weaker centers form cokes of a more saturated chemical nature. On very very weak centers, cokes with the ratio of C H < 1 are formed and such cokes show low catalytic activity for oxidative dehydrogenation. Based on ESR measurements, it has been suggested that paramagnetic centers are the active sites for styrene formation in the process of ethylbenzene oxidative dehydrogenation.