Benzene Alkylation with Propane over Mo Modified HZSM-5

Abstract

Benzene alkylation with propane has been studied over HZSM-5 loading 3.1-15.4 wt% Mo in continuous-flow microreactor under 350°C and atmospheric pressure with the highest activity obtained at 6.7 wt% Mo loading. C 7-9 aromatics were obtained as main products while the total amount of benzene rings kept unchanged. iPropylbenzene and n-propylbenzene are formed primarily, while toluene, ethylbenzene, and ethyl-toluene are formed secondly from the propylbenzenes. Catalytic performance of 6.7 wt% Mo/HZSM-5(38) partially poisoned by NH 3 shows that the strong acid sites play a crucial role in the alkylation. Low SiO 2 /Al 2 O 3 ratio of HZSM-5 in the Mo modified catalysts gives high propane conversion. Two hydrothermal treatment methods were applied to the 6.7 wt% Mo/HZSM-5(38) catalyst, caused decrease of propane conversion but result in different product distribution. A possible reaction mechanism concerning bifunctional active centers resulted from combination of loaded Mo species and strong acid centers on HZSM-5 is proposed.

Thermochemical lignin depolymerization and conversion to aromatics in subcritical methanol: effects of catalytic conditions

“…This can be supported by the reports where HZSM-5 has been used as a heterogeneous solid catalyst for the alkylation of aromatic benzene rings. 26,27 The methylation of phenolic rings retard the condensation polymerization pathways as shown in Scheme 2B, thereby, providing enhanced lignin depolymerization and favouring higher monomers and oligomers compared to THF insolubles. Similar methylation was also observed by Huang et al 28 in the thermocatalytic process for the depolymerization of lignin in supercritical ethanol/methanol over a CuMgAlO x catalyst.…”

Selective Production of 2-Phenylhexane from Benzene and n-Hexane Over Pt- and Ga-Modified Zeolites

“…Although very high conversion and selectivity were reached with superacids, such processes have many environmental drawbacks. Solid acids, such as zeolites [6][7][8][9][10][11][12][13][14][15][16][17], often modified with Pd, Pt, or Ga [2,3,12], do not have these drawbacks. However, they have low activity and selectivity towards alkylaromatic products at moderate reaction temperature (vide infra).…”

“…However, they have low activity and selectivity towards alkylaromatic products at moderate reaction temperature (vide infra). Ethane [7, 12, 14-16, 18, 19] and propane [7][8][9][10][11]13] have been used to date to alkylate aromatics over zeolite-based catalysts. A selectivity of 80% to ethylbenzene was obtained over Pt/H-ZSM-5 by alkylation of benzene with ethane at a conversion of about 2% in ethane [16].…”

n-Hexaneactivation over zeolites: aromatic alkylation to 1-phenylhexane

“…The synthesis of alkylaromatics from alkanes and aromatics in superacidic media 4 and over zeolites at moderate temperature has been reported. [5][6][7][8][9][10][11][12][13][14][15] In homogeneously catalyzed reactions, C 2 -C 5 alkanes were used as alkylating agents; conversions of up to 10% were reached after six hours at ambient temperature. 4 Tertiary, secondary, and primary C-H and C-C bonds underwent protolysis.…”

“…16 The heterogeneously catalyzed aromatic alkylation with alkanes has not been studied in depth. Until now, ethane 5,6,[13][14][15] and propane [6][7][8][9][10]12 have generally been used. Over some bifunctional Pt- 7,8 and Ga-modified 9,10 ZSM-5 zeolites, there was considerable conversion of propane, however, the yield was usually quite low.…”