K., A., A., H., A., G., A., A. (2008). PARA-XYLENE MAXIMIZATION-PART VII ALKYLATION OF TOLUENE WITH METHANOL AND DIFFUSION EFFECTS ON DIFFERENTLY HYDROFLUORINATED H-ZSM-5 CATALYSTS. test, 4(4th International Conference On Chemical & Environmental Engineering), 144-159. doi: 10.21608/iccee.2008.38384
ABOUL-GHEIT A. K.; HANAFI, S. A.; GHONEIM, S. A.; ABOUL-ENEIN, A. A.. "PARA-XYLENE MAXIMIZATION-PART VII ALKYLATION OF TOLUENE WITH METHANOL AND DIFFUSION EFFECTS ON DIFFERENTLY HYDROFLUORINATED H-ZSM-5 CATALYSTS". test, 4, 4th International Conference On Chemical & Environmental Engineering, 2008, 144-159. doi: 10.21608/iccee.2008.38384
K., A., A., H., A., G., A., A. (2008). 'PARA-XYLENE MAXIMIZATION-PART VII ALKYLATION OF TOLUENE WITH METHANOL AND DIFFUSION EFFECTS ON DIFFERENTLY HYDROFLUORINATED H-ZSM-5 CATALYSTS', test, 4(4th International Conference On Chemical & Environmental Engineering), pp. 144-159. doi: 10.21608/iccee.2008.38384
K., A., A., H., A., G., A., A. PARA-XYLENE MAXIMIZATION-PART VII ALKYLATION OF TOLUENE WITH METHANOL AND DIFFUSION EFFECTS ON DIFFERENTLY HYDROFLUORINATED H-ZSM-5 CATALYSTS. test, 2008; 4(4th International Conference On Chemical & Environmental Engineering): 144-159. doi: 10.21608/iccee.2008.38384

PARA-XYLENE MAXIMIZATION-PART VII ALKYLATION OF TOLUENE WITH METHANOL AND DIFFUSION EFFECTS ON DIFFERENTLY HYDROFLUORINATED H-ZSM-5 CATALYSTS

The International Conference on Chemical and Environmental Engineering
Article 9, Volume 4, 4th International Conference On Chemical & Environmental Engineering, May 2008, Pages 144-159    PDF (359.71 K)
Document Type: Original Article
DOI: 10.21608/iccee.2008.38384
Authors
ABOUL-GHEIT A. K.1; HANAFI, S. A.1; GHONEIM, S. A.2; ABOUL-ENEIN, A. A.3
1Egyptian Petroleum Research Institute, P.O. Box 9540, Nasr City, Cairo 11787, Egypt.
2Egyptian Petroleum Research Institute, P.O. Box 9540, Nasr City, Cairo 11787, Egypt. Corresponding author.
3Egyptian Petroleum Research Institute, P.O. Box 9540, Nasr City, Cairo 11787, Egypt
Abstract
ABSTRACT
There is a considerable industrial demand for para-xylene because of its importance as raw material for the manufacture of terphthalic acid, which a major component in the production of polyester fibers, polyethylene terephthalate resins, vitamins and other pharmaceuticals. In this work, H-ZSM-5 zeolite was hydrofluorinated to modify its acid sites number and strength. This zeolite, before and after HF treatment was tested as a catalyst for the alkylation of toluene with methanol at reaction temperatures of 300-500oC, molar ratio of methanol to toluene of 2.5 and liquid hourly space velocity of 2.6v/v/h. HF acid concentrations between 1.0 and 4.0wt% were also examined. The reaction selectivity for para-xylene production has been found to reach an optimum at an HF concentration of 3.0wt%. The catalysts were characterized by temperature programmed desorption (TPD) of ammonia for acid sites distribution analysis. The BET surface area and pore volume for each catalyst were also estimated. Higher concentrations of HF have been found to cause leaching of the structural aluminium of the zeolite, causing fluoro-alumino debris that results in blocking of the channels of this zeolite and giving higher values of Thiele modulus (ФL) and hence lower values of effectiveness factor (η). The simple kinetic evaluation of the reaction rate constant, k, and apparent activation energy were carried out.
Keywords
H-ZSM-5; alkylation; Toluene; Methanol; dealumination; hydrofluorination; and Diffusion
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