Oxidative dehydrogenation of iso-butane to iso-butene II. Rare earth phosphate catalysts

Takita, Yusaku; Sano, Ken‐Ichi; Muraya, Toshio; Nishiguchi, Hiroyasu; Kawata, Noboru; Ito, Masami; Akbay, Taner; Ishihara, Tatsumi

doi:10.1016/s0926-860x(98)00043-x

Cited by 84 publications

(47 citation statements)

References 10 publications

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“…When adopting lanthanum and phosphorus altogether to modify the zeolite Y, a part of La 3+ can be exchanged with sodium into the super-cage in the zeolite, and the other part can easily react with phosphorus to form superfine complex La-P-O oxides, which obviously precipitate on the exterior surface of zeolite and unavoidably cover part of the surface acid sites. 18 The phosphorus reacted with zeolite Y to form P-OH bonds, and the surface acidity density reduced suitably. Through properly increased acid strength in the pores of zeolite Y, the catalyst effectively controlled the ratio of hydrogen transfer activity and crack ability in the catalytic reaction.…”

Section: Catalytic Properties Evaluationmentioning

confidence: 99%

An FCC Catalyst for Maximizing Gasoline Yield

He¹,

Zheng²,

Dai³

2017

Kem. Ind.

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A Y zeolite-containing wide-pore composite was synthesized by in situ technique using polyvinyl alcohol and silica sol material. A fluid catalytic cracking (FCC) catalyst for maximizing gasoline yield was successfully developed with the modified composition. The as-made zeolite Y in its sodium form had a relative crystallinity of 52.9 % with a high silica/alumina amount of substance ratio of 5.7. The FTIR analysis showed that the acid distribution of the catalyst modified with rare earth, phosphorus and steaming stabilization process was more concentrated on the range of intermediate and strong acidity. This kind of modification can direct more hydrocarbons to enter into the pores to be converted, as well as remarkably increases the possibility of gasoline formation through a cracking reaction. The nitrogen adsorption-desorption analysis showed that the catalyst had more meso-and macro-pores distribution, which can effectively reduce the mass-transfer resistance in the reaction process and accelerate the diffusion of the product molecules. The evaluated results indicated that the prepared catalyst could decrease the excessive cracking of middle distillate and improve the gasoline yield effectively. The gasoline yield by mass had increased by 2.69 %, while the coke yield and dry gas yield had decreased by 0.91 % and 0.19 %, respectively, and then the olefin content by volume in the cracked gasoline reduced by 4.6 %, the research octane number (RON) and motor octane number (MON) increased by 0.6 and 0.5, respectively. The good product selectivity and higher gasoline yields of the prepared catalyst were obviously related to its wide pore structure and its optimized acidity distribution.

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Section: Catalytic Properties Evaluationmentioning

confidence: 99%

An FCC Catalyst for Maximizing Gasoline Yield

He¹,

Zheng²,

Dai³

2017

Kem. Ind.

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“…Moreover, these phosphates were used for various reactions like oxidative dehydrogenation of isobutane to isobutene, alkylation of phenol, dehydration of alcohol, etc., [32,33]. Basically, the rare earth oxides such as cerium oxide are basic in nature and introduction of phosphate groups leads to possesses both acidic and basic sites on the surface.…”

Section: Introductionmentioning

confidence: 99%

Vapor-phase catalytic dehydration of lactic acid to acrylic acid over nano-crystalline cerium phosphate catalysts

et al. 2016

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A series of cerium phosphate (CeP) catalysts were synthesized using precipitation method with varying Ce/P mole ratios ranging from 0.5 to 3.0 followed by calcination. The formation of cerium phosphate was confirmed by X-ray diffraction and FT-IR techniques. The catalysts were further characterized to understand the morphology, surface area by using transmission electron microscopy (TEM) and N 2 -sorption measurements. The acidic and basic sites were measured by CO 2 -TPD, NH 3 -TPD and ex situ pyridine FT-IR methods. These calcined CeP catalysts were employed for the dehydration of lactic acid (LA) to acrylic acid (AA) under vapor-phase reaction conditions. Among the catalysts examined, CeP catalyst with Ce/P mole ratio 2.5 (CeP(2.5)) was found to exhibit better catalytic performance with conversion of lactic acid *100 and 64 % selectivity towards acrylic acid at optimized conditions. Time-on-stream experiments suggest that CeP(2.5) catalyst exhibited constant activity until 20 h after which a slight drop of conversion of lactic acid was noticed. The characterization studies of the spent catalysts using thermogravimetric (TG), CHNS analysis and FT-IR reveal the presence of carbonaceous species over the catalyst surface causing deactivation of the catalyst.

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“…What's more, the frequent (15-30 minutes) regeneration 12 of catalyst might be an energy consumptive process. Other substitute catalysts currently explored, such as vanadium oxide, 16,17 pyrophosphate 18,19 and molybdate 20,21 suffer from poor conversion, low selectivity or quick deactivation.…”

Section: Introductionmentioning

confidence: 99%

Insights into the carbon catalyzed direct dehydrogenation of isobutane by employing modified OMCs

Zhang

Yang

Wang

et al. 2016

Catal. Sci. Technol.

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To identify the possible reaction mechanism of carbon-based catalysts for the isobutane direct dehydrogenation (DDH) reaction, a series of modified ordered mesoporous carbons (OMCs) with different surface oxygen contents were prepared and employed as representative catalysts. The OMCs were synthesized by employing SBA-15 as template, and the different oxygen contents were realized by the subsequent oxidation and reduction treatments. According to the characterization results, the treatments have significantly influenced the surface properties, while no obvious change was observed in their pore structure. The differences of surface properties due to the different treatments, and the changes in pore structure and oxygen contents after being used as catalysts, were employed to identify the possible active sites in the carbon catalyzed direct dehydrogenation (DDH) of isobutane. The carbon-based catalysts kept a good stability over a long period of time. The activity was mainly provided by the defects/vacancies on the surface of the carbon materials, and generated coke was also found to be active at a relatively lower level.

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Oxidative dehydrogenation of iso-butane to iso-butene II. Rare earth phosphate catalysts

Cited by 84 publications

References 10 publications

An FCC Catalyst for Maximizing Gasoline Yield

An FCC Catalyst for Maximizing Gasoline Yield

Vapor-phase catalytic dehydration of lactic acid to acrylic acid over nano-crystalline cerium phosphate catalysts

Insights into the carbon catalyzed direct dehydrogenation of isobutane by employing modified OMCs

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