Toluene disproportionation over nickel-loaded aluminum-deficient mordenite. 2. Kinetics

Abstract

A kinetic investigation was conducted for the toluene disproportionation reaction in the presence of a particular zeolite, namely (0.2 wt %) nickel-loaded mordenite with a silica:alumina ratio of 23. Process variables studied were catalyst size, temperature, and contact time. The reaction rate constants calculated on the basis of a reversible second-order reaction model fitted an Arrhenius function of temperature with an apparent activation energy of 14.5 kcal/mol. For the falling rate period, the activity of the catalyst ( ) decreased with time on stream (t) according to the relationship = 0oe~mf, where m was approximately equal to 3 X 10"3 at 350 °C and above.Kinetic studies of toluene disproportionation are mainly confined to conventional acid catalysts (Izumi and Shiba, 1963; Ai et al., 1965;Ogawa et al., 1969; Iwamura et al., 1971). Although zeolites have been proved to be highly active catalysts for this reaction, there are only a few reports on kinetic studies using such a type of catalysts, namely, that of Yashima et al. (1970) on H-mordenite, and Aneke et al. (1979) ón a composite catalyst containing H-Y zeolite, A1F3, and copper. The present paper describes the

Kinetics of toluene disproportionation over fresh and coked H-mordenite

“…The kinetics models in earlier literatures were in great discrepancy. Bhavikatti and Patwardhan observed a reversible second-order reaction model over Ni/mordenite with an activation energy of 14.5 kcal/mol [2]. Bharati and Bhatia observed a single-site adsorption over H-mordenite catalyst [5].…”

“…Reaction kinetics study has shown to be a crucial research subject for process development, which provides valuable data for reactor design, process optimization, and cycle length prediction. Various kinetic models were proposed for toluene disproportionation (TDP) over several zeolites [2][3][4][5][6][7][8]. Most of the published reports studied mainly on the initial kinetics at low conversion levels and in short onstream time (TOS) with very low coke formation.…”

A Novel Approach for Prediction of Industrial Catalyst Deactivation Using Soft Sensor Modeling

“…The major problem for the commercialization of solid acid catalyzed processes is the rapid deactivation of the catalyst [4,6,7]. Therefore, modeling of the deactivation of the catalyst is a major problem that must be taken into account for the success of such processes.…”

“…In these models, however, many simplified conditions have been assumed. Most of these models have been conducted at the laboratory scale under certain conditions with applying no dynamic data [1][2][3][4][5][6][7]12]. Additionally, online investigation of the industrial reactors' parameters (e.g., catalyst deactivation, conversion, product…”

Catalytic Para‐Xylene Maximization. V. Toluene Methylation with Methanol and Disproportionation of Toluene Using Pt/ZSM‐5 and Pt/Mordenite Catalysts

“…[1][2][3][4][5] In general, mixtures of xylenes can be produced by alkylation of toluene with methanol [6][7][8][9][10][11] or disproportionation of toluene, which produces benzene and xylenes. [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] The old alkylation process uses AlCl3, 8,27 which is corrosive and associated with tedious disposal problems. Synthetic zeolites have attracted attention as alkylation catalysts owing to their higher acidity, freedom from corrosive substances, potential for regeneration, easy separation from reaction products and elimination of problems associated with disposal of spent catalyst.…”