One-Step Alkylation of Benzene with Syngas over Non-Noble Catalysts Mixed with Modified HZSM-5

Abstract

para-Xylene is an important chemical for industry. In this work, alkylation of benzene with syngas (ABS) is carried out to prepare toluene and xylene over zinc/ chromium (Zn/Cr) oxide and modified HZSM-5. The catalyst with a Zn/Cr ratio of 1.6 and 20% (wt) silicate-1 zeolite (S1) coated HZSM-5 has the best catalytic performance, exhibiting 34.4% benzene conversion and 94.7% total selectivity of toluene and xylene, with 73.2% of xylene as para-xylene. The catalyst is carefully characterized; results showed that the activity was enhanced by excessive zinc atoms, which would replace the surface chromium atoms, and this substitution led to more oxygen vacancies. Besides, by coating a layer of S1 on HZSM-5, the production of trimethylbenzene was suppressed and the selectivity of para-xylene among all xylene was increased, due to the coverage of zeolite surface acid sites. These findings are helpful for understanding the one-pot syngas conversion and benzene alkylation processes.

Synthesis Gas Conversion to Lower Olefins over ZnCr‐SAPO‐34 Catalysts: Role of ZnO−ZnCr2O4 Interface

“…This can be interpreted as a transfer of electrons, resulting in an rich electron environment of Cr . The deconvoluted results show that in addition to Cr 6+ and Cr 3+ , the lower valence of Cr (noted as Cr (3−δ)+ ) also exist at ∼575.0 eV in Zn 1 Cr 1 . The electron transfer could be facilitated by the formation of heterogeneous interfaces between two semiconductor materials .…”

“…[36] The deconvoluted results show that in addition to Cr 6 + and Cr 3 + , the lower valence of Cr (noted as Cr (3À δ) + ) also exist at 575.0 eV in Zn 1 Cr 1 . [37] The electron transfer could be facilitated by the formation of heterogeneous interfaces between two semiconductor materials. [38] Compared to Zn 1 Cr 1 , the degree of shift toward to low binding energy is alleviated in Zn 2 Cr 1 .…”

One-Pass Conversion of Benzene and Syngas to Alkylbenzenes by Cu–ZnO–Al2O3 and ZSM-5 Relay

“…There is a temperature matching relationship between the two components in the Cu–ZnO–Al 2 O 3 /ZSM-5(31) dual-function catalyst [ 20 , 49 ]. Generally, the temperature of Cu–ZnO–Al 2 O 3 catalyzed synthesis of methanol at 230–280 °C [ 50 – 52 ], while the HZSM-5 catalyzed benzene and methanol alkylation needs to be higher than 400 °C [ 20 , 49 ].…”

“…There is a temperature matching relationship between the two components in the Cu–ZnO–Al 2 O 3 /ZSM-5(31) dual-function catalyst [ 20 , 49 ]. Generally, the temperature of Cu–ZnO–Al 2 O 3 catalyzed synthesis of methanol at 230–280 °C [ 50 – 52 ], while the HZSM-5 catalyzed benzene and methanol alkylation needs to be higher than 400 °C [ 20 , 49 ]. In the Cu–ZnO–Al 2 O 3 /ZSM-5(31) catalyzed alkylation reaction of benzene and syngas, when the temperature is lower than 400 °C, although it is beneficial to the production of intermediate methanol from syngas on Cu–ZnO–Al 2 O 3 , the ability of ZSM-5 to activate benzene is limited due to the low reaction temperature.…”

Aromatik Karışımların Hidrodealkilasyonuna Katalizör Modifikasyonun Etkisi

“…A proper solution for the deactivation of the catalysts during hydrocarbon processing is the incorporation of various metals (Ni, Mo, V, Cs etc.) into the catalysts [7,[10][11][12][13][14].…”