Catalytic transformation of C7–C9 methyl benzenes over USY-based FCC zeolite catalyst

Al-Khattaf, S.; Tukur, Nasiru M.; Al-Amer, Adnan M.; Al-Mubaiyedh, Usamah A.

doi:10.1016/j.apcata.2006.02.043

Cited by 25 publications

(35 citation statements)

References 37 publications

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“…Disproportionation reaction of toluene alone over FCC-Y catalyst was reported in our earlier publication [10]. No transformation of toluene into xylenes was observed for this catalyst.…”

Section: Toluene Disproportionation and 124-trimethylbenzene Reactionmentioning

confidence: 99%

“…Since very negligible amount of toluene was found during the transformation reaction of 1,2,4-TMB alone as presented in Table 2 and ref. [10], thus, the reactivity of toluene can only be attributed to the transalkylation reaction. By blending trimethylbenzene with toluene, the average methyl group number per benzene ring is increased leading to higher reactivity as pointed out in ref.…”

Section: 23-and 135-isomers) As Well As Xylene Isomerization (Omentioning

confidence: 99%

“…The study will focus on the effect of reaction conditions (time, temperature, and conversion) on xylene yields, p-xylene/o-xylene (P/O) and 1,3,5-to-1,2,3-TMB ratios. Comparisons will also be made with our earlier reported studies on catalytic transformations of toluene and 1,2,4-TMB, each alone [10,11]. An attempt will also be made to model the transalkylation reaction of 1,2,4-TMB with toluene taking into consideration the major side reactions taking place.…”

mentioning

confidence: 99%

“…However, toluene that was found almost inactive [10], became reactive upon blending with 1,2,4-TMB. Since very negligible amount of toluene was found during the transformation reaction of 1,2,4-TMB alone, thus, the reactivity of toluene can only be attributed to the transalkylation reaction.…”

mentioning

confidence: 99%

“…Al-Khattaf et al [10] studied the transformation of toluene, xylenes, and TMB over YZeolite catalyst in a riser simulator. They found that the sequence of reactivity of the three alkyl benzenes decreases as the number of methyl group per benzene ring decreases, as follows: 1,2,4-trimethyl benzene > m-xylene > toluene.…”

mentioning

confidence: 99%

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1,2,4-Trimethylbenzene Transformation Reaction Compared with its Transalkylation Reaction with Toluene over USY Zeolite Catalyst

Al-Khattaf

Tukur

Al-Amer

2007

Ind. Eng. Chem. Res.

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Abstract1,2,4-Trimethyl benzene (TMB) transalkylation with toluene has been studied over USY-zeolite type catalyst using a riser simulator that mimics the operation of a fluidized-bed reactor. 50:50 wt% reaction mixtures of TMB and toluene were used for the transalkylation reaction. The range of temperature investigated was 400-500 o C and time on stream ranging from 3 to 15 seconds.The effect of reaction conditions on the variation of p-xylene to o-xylene products ratio (P/O), distribution of trimethylbenzene (TMB) isomers (1,3,5-to-1,2,3-) and values of xylene/tetramethylbenzenes (X/TeMB) ratios are reported. Comparisons are made between the results of the transalkylation reaction with the results of pure 1,2,4-TMB and toluene reactions earlier reported. Toluene that was found almost inactive, became reactive upon blending with 1,2,4-TMB. This shows that toluene would rather accept a methyl group to transform to xylene than to loose a methyl group to form benzene under the present experimental condition with pressures around ambient. The experimental results were modeled using quasi-steady state approximation. Kinetic parameters for the 1,2,4-TMB disappearance during the transalkylation reaction, and in its conversion into isomerization and disproportionation products were calculated using the catalyst activity decay function based on time on stream (TOS). The apparent activation energies were found to decrease as follows: E transalkylation > E isomerization > E disproportionation . February 2007Keywords: Trimethyl benzene transalkylation, toluene reaction, fluidized-bed reactor, USY-zeolite, xylene yield * Corresponding author. Tel.: +966-3-860-1429; Fax: +966-3-860-4234 e-mail address: skhattaf@kfupm.edu.sa 2 Introduction:The demand for xylenes as a raw material for polyester fibers and films continues to grow and drive the search to increase xylene production processes. In the year 1999, the world consumption of mixed xylene was about 24 million tons, and is expected to grow at a rate of 6.2% to 35.9 million tons by the year 2007. This indicates that xylenes are still gaining importance in the petrochemical market. Among the three xylene isomers, p-xylene is the most demanded and thus most expensive, followed by o-xylene.One common way for xylene production is the conversion of the lower value toluene (C 7 ) and trimethylbenzene (C 9 ) into xylenes via toluene disproportionation, trimethyl benzene (TMB) disproportionation and transalkylation with toluene. Thus, these processes offer a way to utilize the low cost toluene and TMB to produce much more attractive product xylene. TMB disproportionation, and toluene-TMB transalkylation. They found that the zeolite beta has excellent stability and transalkylation selectivity. In TMB disproportionation, blending toluene into feedstocks can shift the production selectivity of TeMB to xylene, whereas in toluene disproportionation, mixing TMB into feedstocks not only reduced the reaction temperatures but also raised the xylene yield. Das et al.[4] also studied the t...

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“…Disproportionation reaction of toluene alone over FCC-Y catalyst was reported in our earlier publication [10]. No transformation of toluene into xylenes was observed for this catalyst.…”

Section: Toluene Disproportionation and 124-trimethylbenzene Reactionmentioning

confidence: 99%

Section: 23-and 135-isomers) As Well As Xylene Isomerization (Omentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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1,2,4-Trimethylbenzene Transformation Reaction Compared with its Transalkylation Reaction with Toluene over USY Zeolite Catalyst

Al-Khattaf

Tukur

Al-Amer

2007

Ind. Eng. Chem. Res.

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Production of Xylenes from Toluene and 1,2,4‐Trimethylbenzene over ZSM‐5 and Mordenite Catalysts in a Fluidized‐Bed Reactor

2010

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The production of various xylenes from toluene, heavy aromatics such as 1,2,4-trimethylbenzene (1,2,4-TMB) and their mixture was investigated over H-ZSM-5 (H-Z), H-mordenite (H-M) and a dual zeolitic catalyst comprising ZSM-5 and mordenite (H-ZM). The experiments were conducted in a riser-simulator reactor under different operating conditions to study the effect of temperature, reaction time and feed composition on conversion and product yields. At 400°C, the conversion of toluene over the three catalysts yielded mainly benzene and xylenes with maximum conversion at 25 % and a xylene yield of 12.5 wt % over the H-M catalyst. The transformation of 1,2,4-TMB doubled the conversion level and xylene yield and suppressed benzene formation. However, a considerable portion of the 1,2,4-TMB feed was isomerized into 1,2,3-TMB and 1,3,5-TMB accompanied by the formation of tetramethylbenzenes (TeMBs). The conversion of an equimolar mixture of toluene and 1,2,4-TMB over the three catalysts resulted in higher toluene conversion and double xylene yield in comparison with 1,2,4-TMB alone. The advantage of using a dual zeolitic catalyst was observed at an equimolar feed of toluene and 1,2,4-TMB, exhibiting maximum toluene conversion, higher xylene yield and the formation of lower levels of undesirable products.

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The Role of Crystallization Parameters for the Synthesis of Germanosilicate with UTL Topology

Швец¹,

Zukal²,

Kasian³

et al. 2008

Chemistry A European J

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The investigation of the critical synthesis parameters of germanosilicate of UTL topology, possessing 14- and 12-rings, has been carried out in detail. (6R,10S)-6,10-Dimethyl-5-azoniaspiro[4.5]decane hydroxide was used as the structure-directing agent (SDA). The kinetics of the synthesis, the role of the Si/Ge ratio in the synthesis mixture, and the effect of the calcination procedure were investigated in relation to the crystallinity and textural properties of the synthesized material. The optimum synthesis time was found to be six days for Si/Ge and (Si+Ge)/SDA molar ratios of 2 and 1.7, respectively. The UTL zeolite crystallizes as small sheets of 10 mum in size. The micropore volume of the best crystals is 0.22 cm(3) g(-1) with a micropore diameter of 1.05 nm, based on DFT and Saito-Foley analyses of adsorption data.

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Catalytic transformation of C7–C9 methyl benzenes over USY-based FCC zeolite catalyst

Cited by 25 publications

References 37 publications

1,2,4-Trimethylbenzene Transformation Reaction Compared with its Transalkylation Reaction with Toluene over USY Zeolite Catalyst

1,2,4-Trimethylbenzene Transformation Reaction Compared with its Transalkylation Reaction with Toluene over USY Zeolite Catalyst

Production of Xylenes from Toluene and 1,2,4‐Trimethylbenzene over ZSM‐5 and Mordenite Catalysts in a Fluidized‐Bed Reactor

The Role of Crystallization Parameters for the Synthesis of Germanosilicate with UTL Topology

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