Improved p-Xylene Selectivity of n-Pentane Aromatization over Silylated Ga-exchanged HZSM- 5 Catalysts
In this study, the conversion of n-pentane to aromatics is investigated on HZSM-5 zeolites modified by Ga ion-exchange and silylation using tetraethyl orthosilicate (TEOS) via chemical liquid deposition (CLD). The effect of SiO2/Al2O3 ratios of HZSM-5 was also studied. Parameters in preparing catalysts i.e. TEOS loading and cycles of deposition were varied to obtain the optimal condition for enhancing p-xylene selectivity. The highest p-xylene selectivity 99.7% was achieved when the amount of TEOS was 20 vol.%.The catalysts were characterized by TPD, TPO, XRF, and BET. Results show that the conversion of n-pentane was influenced remarkably by the SiO2/Al2O3 ratios of HZSM-5. The highest p-xylene selectivity 99.7% was achieved when the amount of TEOS was 20 vol.%. And cycles of deposition greatly improves HZSM-5 shape-selectivity.
[1] Chatterjee, A., Bhattacharya, D., Chatterjee, M. and Iwasaki, T. (1999).
Suitability of using ZSM-5 over other medium pore zeolites for nhexane
aromatization a density functional study. Microporous and
Mesoporous Materials, 32, 189-198.
[2] Bhattacharya, D., Sivasanker, S. (1995). A comparison of
aromatization activities of the medium pore zeolites, ZSM-5, ZSM-22
and Eu-1. Journal of Catalysis, Volume 153, Issue 2, 353-355.
[3] Csicsery, S.M. (1984). Shape-selective Catalyst in Zeolite. Zeolite,
Vol. 4, Issue 3, 202-213.
[4] Danuthai, T., Jongpatiwut, S., Rirksomboon, T., Osuwan, S. and
Resasco, D.E. (2009). Conversion of methylesters to hydrocarbons over
an H-ZSM-5 zeolite catalyst. Applied Catalysis A: General, 361, 99-
105.
[5] Viswanadham, N., Muralidhar, G. and Rao, T.S.R.P (2004). Cracking
and aromatization properties of some metal modified ZSM-5 catalysts
for light alkane conversions. Journal of Molecular Catalysis A:
Chemical, 223, 269-274.
[6] Antos, G.J., and Aitani, A.M. (2004). Catalytic Naphtha Reforming:
Science and Technology, New York: Marcel Dekker.
[7] Bhattacharya, D. and Sivasanker, S. (1996). Aromatization of n-hexane
over H-ZSM-5: Influence of promoters and added gases. Applied
Catalysis A: General, 141, 105-115.
[8] Bhat, Y.S., Das, Das, J., and Halgeri, A.B (1995). Coke Induced
Stabilization of Catalytic Actvity of Silylated ZSM-5 Zeolite. Journal of
catalysis, 155, 154-157.
[9] Dooley, K.M., Price, G.L., Kanazirev, V.I. and Hart, V.I. (1996).
Gallium-loaded zeolites for light paraffin aromatization: evidence for
exchanged gallium cation active centers. Catalysis Today, 31, 305-315.
[10] Choudhary, V.R., Mulla, S.T.R. and Banerjee, S. (2003).
Aromatization of n- heptane over H-AlMFI, Ga/H-AlMFI, H-GaMFI
and H-GaAlMFI zeolite catalysts : influence of zeolitic acidity and nonframe
work gallium. Microporous and Mesoporous Materials, 57, 317-
322.
[11] Gnep, N.S., Doyemet, J.Y., Seco, A.M., Ramao Rebeiro, F. and Guisnet,
M. (1988). Conversion of Light Alkanes to Aromatic Hydrocarbon. II
Role of Gallium Species in Propane Transformation on GaHZSM-5
Catalysts. Applied Catalysis, 43, 155.
[12] Halasz, J., Konya, Z., Fudala, A., Beres, A., Kiricsi, I. (1996). Indium
and gallium containing ZSM-5 zeolites: acidity andcatalytic activity in
propane transformation. Catalysis Today, 31, 293-304.
[13] Zhu, Z., Xie, Z., Chen, Q., Kong, D., Li, W., Yang, W. and Li, C.
(2007). Chemical liquid deposition with polysiloxane Of ZSM-5 and its
effect on acidity and catalytic properties. Microporous and Mesoporous
Materials, 101, 169-175.
[14] Teng, H., Wang, J., Ren, X. and Chen, D. (2011). Disproportionation of
toluene by modified ZSM-5 zeolite catalysts with high shape-selectivity
prepared using chemical liquid deposition with tetraethyl orthosilicate.
Chinese Journal of Chemical Engineering, 19(2), 292-298.
[15] Zheng, S., Heydenrych, H. R., Roger, H. P., Jentys, A. and Lercher, J.A.
(2003). On the enhanced selectivity of HZSM-5 modified by chemical
liquid deposition. Topics in Catalysis, Vol. 22, Nos ›, 101-106.
[16] Liu, C., Deng, Y., Pan, Y., Gu, Y., Qiao, B. and Gao, X. (2004). Effect
of ZSM-5 on the aromatization performance in cracking catalyst.
Journal of Molecular Catalysis A: Chemical, l215, 195-199.
[17] Zhu, Z., Xie, Z., Chen, Q., Kong, D., Li, W., Yang, W. and Li, C.
(2007). Chemical liquid deposition with polysiloxane of ZSM-5 and its
effect on acidity and catalytic properties. Microporous and Mesoporous
Materials, 101, 169-175.
[1] Chatterjee, A., Bhattacharya, D., Chatterjee, M. and Iwasaki, T. (1999).
Suitability of using ZSM-5 over other medium pore zeolites for nhexane
aromatization a density functional study. Microporous and
Mesoporous Materials, 32, 189-198.
[2] Bhattacharya, D., Sivasanker, S. (1995). A comparison of
aromatization activities of the medium pore zeolites, ZSM-5, ZSM-22
and Eu-1. Journal of Catalysis, Volume 153, Issue 2, 353-355.
[3] Csicsery, S.M. (1984). Shape-selective Catalyst in Zeolite. Zeolite,
Vol. 4, Issue 3, 202-213.
[4] Danuthai, T., Jongpatiwut, S., Rirksomboon, T., Osuwan, S. and
Resasco, D.E. (2009). Conversion of methylesters to hydrocarbons over
an H-ZSM-5 zeolite catalyst. Applied Catalysis A: General, 361, 99-
105.
[5] Viswanadham, N., Muralidhar, G. and Rao, T.S.R.P (2004). Cracking
and aromatization properties of some metal modified ZSM-5 catalysts
for light alkane conversions. Journal of Molecular Catalysis A:
Chemical, 223, 269-274.
[6] Antos, G.J., and Aitani, A.M. (2004). Catalytic Naphtha Reforming:
Science and Technology, New York: Marcel Dekker.
[7] Bhattacharya, D. and Sivasanker, S. (1996). Aromatization of n-hexane
over H-ZSM-5: Influence of promoters and added gases. Applied
Catalysis A: General, 141, 105-115.
[8] Bhat, Y.S., Das, Das, J., and Halgeri, A.B (1995). Coke Induced
Stabilization of Catalytic Actvity of Silylated ZSM-5 Zeolite. Journal of
catalysis, 155, 154-157.
[9] Dooley, K.M., Price, G.L., Kanazirev, V.I. and Hart, V.I. (1996).
Gallium-loaded zeolites for light paraffin aromatization: evidence for
exchanged gallium cation active centers. Catalysis Today, 31, 305-315.
[10] Choudhary, V.R., Mulla, S.T.R. and Banerjee, S. (2003).
Aromatization of n- heptane over H-AlMFI, Ga/H-AlMFI, H-GaMFI
and H-GaAlMFI zeolite catalysts : influence of zeolitic acidity and nonframe
work gallium. Microporous and Mesoporous Materials, 57, 317-
322.
[11] Gnep, N.S., Doyemet, J.Y., Seco, A.M., Ramao Rebeiro, F. and Guisnet,
M. (1988). Conversion of Light Alkanes to Aromatic Hydrocarbon. II
Role of Gallium Species in Propane Transformation on GaHZSM-5
Catalysts. Applied Catalysis, 43, 155.
[12] Halasz, J., Konya, Z., Fudala, A., Beres, A., Kiricsi, I. (1996). Indium
and gallium containing ZSM-5 zeolites: acidity andcatalytic activity in
propane transformation. Catalysis Today, 31, 293-304.
[13] Zhu, Z., Xie, Z., Chen, Q., Kong, D., Li, W., Yang, W. and Li, C.
(2007). Chemical liquid deposition with polysiloxane Of ZSM-5 and its
effect on acidity and catalytic properties. Microporous and Mesoporous
Materials, 101, 169-175.
[14] Teng, H., Wang, J., Ren, X. and Chen, D. (2011). Disproportionation of
toluene by modified ZSM-5 zeolite catalysts with high shape-selectivity
prepared using chemical liquid deposition with tetraethyl orthosilicate.
Chinese Journal of Chemical Engineering, 19(2), 292-298.
[15] Zheng, S., Heydenrych, H. R., Roger, H. P., Jentys, A. and Lercher, J.A.
(2003). On the enhanced selectivity of HZSM-5 modified by chemical
liquid deposition. Topics in Catalysis, Vol. 22, Nos ›, 101-106.
[16] Liu, C., Deng, Y., Pan, Y., Gu, Y., Qiao, B. and Gao, X. (2004). Effect
of ZSM-5 on the aromatization performance in cracking catalyst.
Journal of Molecular Catalysis A: Chemical, l215, 195-199.
[17] Zhu, Z., Xie, Z., Chen, Q., Kong, D., Li, W., Yang, W. and Li, C.
(2007). Chemical liquid deposition with polysiloxane of ZSM-5 and its
effect on acidity and catalytic properties. Microporous and Mesoporous
Materials, 101, 169-175.
@article{"International Journal of Chemical, Materials and Biomolecular Sciences:50526", author = "Tunchanok Nitipan and Siriporn Jongpatiwut and Thirasak Rirksomboon and Boonyarach Kitiyanan and Tivaporn Apphakvan", title = "Improved p-Xylene Selectivity of n-Pentane Aromatization over Silylated Ga-exchanged HZSM- 5 Catalysts", abstract = "In this study, the conversion of n-pentane to aromatics is investigated on HZSM-5 zeolites modified by Ga ion-exchange and silylation using tetraethyl orthosilicate (TEOS) via chemical liquid deposition (CLD). The effect of SiO2/Al2O3 ratios of HZSM-5 was also studied. Parameters in preparing catalysts i.e. TEOS loading and cycles of deposition were varied to obtain the optimal condition for enhancing p-xylene selectivity. The highest p-xylene selectivity 99.7% was achieved when the amount of TEOS was 20 vol.%.The catalysts were characterized by TPD, TPO, XRF, and BET. Results show that the conversion of n-pentane was influenced remarkably by the SiO2/Al2O3 ratios of HZSM-5. The highest p-xylene selectivity 99.7% was achieved when the amount of TEOS was 20 vol.%. And cycles of deposition greatly improves HZSM-5 shape-selectivity.
", keywords = "Aromatization, Chemical Liquid Deposition (CLD),
p-Xylene, ZSM-5 Zeolite", volume = "6", number = "4", pages = "261-4", }
