TY - JOUR
T1 - Tailoring p-xylene selectivity in toluene methylation on medium pore-size zeolites
AU - Ahn, John H.
AU - Kolvenbach, Robin
AU - Gutiérrez, Oliver Y.
AU - Al-Khattaf, Sulaiman S.
AU - Jentys, Andreas
AU - Lercher, Johannes A.
N1 - Publisher Copyright:
© 2015 Elsevier Inc.
PY - 2015/7/1
Y1 - 2015/7/1
N2 - The p-xylene selectivity in toluene methylation was investigated over medium pore-size zeolites (H-ZSM5, H-ZSM11 and H-NU10) as well as after deposition of tetraethyl orthosilicate on the surface, isomorphous substitution of aluminum by iron and variation the crystal size. Higher reaction temperatures consistently resulted in higher p-xylene selectivity in the three reaction pathways for the formation of p-xylene during toluene methylation, i.e., methylation of toluene, isomerization of xylenes, further methylation and subsequent formation of xylenes after dealkylation of light hydrocarbons. The increased selectivity is attributed to the accumulation of slowly diffusing reaction products in the zeolite pores. Thus, the isomerization of m- and o-xylenes, as well as dealkylation of higher alkylated products influenced the xylene selectivity most strongly at high temperatures, while the intrinsic selectivity of the toluene alkylation dominates at lower reaction temperatures due to the absence of transport restrictions.
AB - The p-xylene selectivity in toluene methylation was investigated over medium pore-size zeolites (H-ZSM5, H-ZSM11 and H-NU10) as well as after deposition of tetraethyl orthosilicate on the surface, isomorphous substitution of aluminum by iron and variation the crystal size. Higher reaction temperatures consistently resulted in higher p-xylene selectivity in the three reaction pathways for the formation of p-xylene during toluene methylation, i.e., methylation of toluene, isomerization of xylenes, further methylation and subsequent formation of xylenes after dealkylation of light hydrocarbons. The increased selectivity is attributed to the accumulation of slowly diffusing reaction products in the zeolite pores. Thus, the isomerization of m- and o-xylenes, as well as dealkylation of higher alkylated products influenced the xylene selectivity most strongly at high temperatures, while the intrinsic selectivity of the toluene alkylation dominates at lower reaction temperatures due to the absence of transport restrictions.
KW - Acid chemistry in zeolites
KW - Methanol conversion
KW - Toluene methylation
KW - Xylene isomerization
KW - p-Xylene selectivity
UR - http://www.scopus.com/inward/record.url?scp=84924081014&partnerID=8YFLogxK
U2 - 10.1016/j.micromeso.2015.02.018
DO - 10.1016/j.micromeso.2015.02.018
M3 - Article
AN - SCOPUS:84924081014
SN - 1387-1811
VL - 210
SP - 52
EP - 59
JO - Microporous and Mesoporous Materials
JF - Microporous and Mesoporous Materials
ER -