Alkylation of benzene with ethanol over ZSM5 zeolites

CHANDAWAR, K. H.; Kulkarni, S. B.; Ratnasamy, P.

doi:10.1016/0166-9834(82)80112-7

Cited by 60 publications

(37 citation statements)

References 6 publications

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“…[6][7][8][9][10] Usually, the improved selectivity towards propylene is attributed to the decrease in the acid site strength that is so often observed in phosphated H-ZSM-5, although steric factors have also been suggested to be responsible. [6][7][8][9][10][11][12] Even though there is still some debate on the effect of acid site strength on the MTO product distribution, the promoting effect of phosphorus on the hydrothermal stability of H-ZSM-5 is undisputed. 4,9,[13][14][15][16][17][18][19][20][21][22][23][24][25] Zeolite H-ZSM-5 catalysts that contain phosphorus are more stable under hydrothermal conditions i.e.…”

Section: Introductionmentioning

confidence: 99%

Local silico-aluminophosphate interfaces within phosphated H-ZSM-5 zeolites

Bij

Weckhuysen

2014

Phys. Chem. Chem. Phys.

127

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In order to elucidate phosphorus-zeolite H-ZSM-5 interactions, a variety of phosphorus-modified zeolite H-ZSM-5 materials were studied in a multi-spectroscopic manner. By deploying single pulse 27 Al, 31 P MAS NMR, 2D heteronuclear 27 Al-31 P correlation (HETCOR), 27 Al MQ MAS NMR spectroscopy, TPD of pyridine monitored by FT-IR spectroscopy, and Scanning Transmission X-ray Microscopy (STXM) the interplay and influence of acidity, thermal treatment and phosphorus on the structure and acidity of H-ZSM-5 were established. It was found that while acid treatment did not affect the zeolite structure, thermal treatment leads to the breaking of Si-OH-Al bonds, a decrease in the strong acid site number and the formation of terminal Al-OH groups. No extra-framework aluminium species was observed. Phosphorus precursors interact with the zeolitic framework through hydrogen bonds and physical coordination, as phosphorus species can be simply washed out with hot water. After phosphatation and thermal treatment two effects occur simultaneously, namely (i) phosphorus species transform into water insoluble condensed poly-phosphoric acid and (ii) phosphoric acid binds irreversibly to the terminal Al-OH groups of partially dislodged four-coordinated framework aluminium, forming local silico-aluminophosphate interfaces.These interfaces are potentially the promoters of hydrothermal stability in phosphated zeolite H-ZSM-5.

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Section: Introductionmentioning

confidence: 99%

Local silico-aluminophosphate interfaces within phosphated H-ZSM-5 zeolites

Bij

Weckhuysen

2014

Phys. Chem. Chem. Phys.

127

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“…The catalytic reaction which uses ethanol for benzene alkylation, instead of ethene, would eliminate the ethene production step and, therefore, leading to the commercial and environmental benefits in the ethylbenzene manufacturing [10]. In addition to the intrinsic scientific interest, the direct use of ethanol (instead of ethene) in the manufacture of ethylbenzene also has economic significance in those countries like Brazil and India, where biomass-derived alcohol is an additional feedstock for the manufacture of chemicals (see Fig.…”

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confidence: 99%

“…Several studies have been reported regarding benzene alkylation using unmodified zeolites like HZSM-5, Beta, HY, mordenite, TNU-9, SSZ-33,ZSM-12, MCM-22 and ITQ-22 [6,[12][13][14][15][16] as well as HZSM-5 modified with phosphorous and boron [10]. Venuto et al [13] had already shown that although Linde type X and Y zeolites exchanged with rare earth ions catalyse the alkylation of benzene with ethanol, the catalyst aging was severe leading to catalyst deactivation in a few hours.…”

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Alkylation of benzene with ethanol over modified HZSM-5 zeolite catalysts

Emana

Chand

2015

Appl Petrochem Res

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Alkylation of benzene with ethanol was analysed using unmodified as well as modified shape selective HZSM-5 (Si/Al = 31) zeolite catalysts. The reaction was carried out in a continuous fixed bed flow reactor in the temperature range of 300-500°C at atmospheric pressure to investigate the activity of various catalysts for the selectivity and yield of ethylbenzene (the desired product). The alkylation of benzene with ethanol (2:1 by volume) produces ethyl benzene as primary product and others like diethylbenzene, triethylbenzene and xylene mixtures as secondary products. The modification of HZSM-5 was done by impregnation using boron and magnesium. The modification caused changes in the surface area, acidity and pore volume of zeolite sample. The physiochemical properties of catalysts were characterised by XRD, TEM, BET, TGA, FTIR, NH 3 -TPD and SEM. The feed and products were analysed by gas chromatography. The conversion of benzene was found to be better in bi metallic (B and Mg) modified HZSM-5 followed by unmodified HZSM-5. The modified catalysts gave better selectivity (72.8 %) and yield (38.1 %) of ethylbenzene.

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“…al. [7] reported that the presence of Β, Ρ and organic bases enhanced para selectivity by suppressing isomerization of primary product, para ethyl toluene. Kim et.…”

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confidence: 98%

Role of Shape Selectivity in n-Heptane Cracking and Aromatization Reaction on Modified ZSM-5

Rao¹,

Viswanadham²,

Dhar³

1999

ACS Symposium Series

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Cracking and aromatization reaction of n-heptane was carried out on ZSM-5 modified by three methods: They are (i) Extra framework alumina obtained by steaming at high temperature, (ii) Altering the pore size by coke deposition as a function of time on stream, and (iii) Presence of amorphous material in the zeolite. The effect of these modifications on the shape selective product p-xylene is investigated. In all the cases the shape selective properties are profoundly influenced. The presence of extra framework alumina, and coke increased the concentration of para xylene in the product. In the case of ZSM-5 containing amorphous material obtained by synthesizing the zeolite without the aid of template, the para xylene in the product was higher than that obtained over zeolite synthesized using the template. In all the cases the increase in shape selective product may be resulted by decrease in channel dimensions due to the presence of the extraneous materials in the channel. Pore size distribution studies on deactivated catalyst provided evidence for the operation of molecular traffic control (MTC) mechanism in the case of n-heptane aromatiztion reaction.Ever since weisz and co-workers from Mobil coined the word shape selectivity and demonstrated its commercial potential using small pore molecular sieves, shape selective properties of zeolites have been studied with great interest [/]. The availability of MFI type medium pore zeolites of ZSM family with pore sizes compatible with molecules in gasoline range has opened up new vistas in hydrocarbon transformations [2,3]. Based on their acidic and shape selective properties a number of processes were developed in the recent past [2]. Xylene isomerization, Methanol to gasoline, Distillate and lube dewaxing, M-forming, Mobil selective toluene disproportionation, manufacture of para diethyl benzene are 130

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Alkylation of benzene with ethanol over ZSM5 zeolites

Cited by 60 publications

References 6 publications

Local silico-aluminophosphate interfaces within phosphated H-ZSM-5 zeolites

Local silico-aluminophosphate interfaces within phosphated H-ZSM-5 zeolites

Alkylation of benzene with ethanol over modified HZSM-5 zeolite catalysts

Role of Shape Selectivity in n-Heptane Cracking and Aromatization Reaction on Modified ZSM-5

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