Formation and Fate of Formaldehyde in the Methanol-To-Hydrocarbons Reaction: An In Situ Synchrotron Radiation Photoionization Mass Spectrometry Study.

Formation and Fate of Formaldehyde in the Methanol-To-Hydrocarbons Reaction: An In Situ Synchrotron Radiation Photoionization Mass Spectrometry Study.
Angew Chem Int Ed Engl. 2020 Jan 14;:
Authors: Wen W, Yu S, Zhou C, Ma H, Zhou Z, Cao C, Yang J, Xu M, Qi F, Zhang G, Pan Y
Abstract
Formaldehyde (HCHO) has been confirmed as an active intermediate in methanol-to-hydrocarbons (MTH) reaction, which is critical for interpreting the mechanisms of coke formation. In this work, HCHO was unambiguously detected and quantified for the first time during the MTH process over HSAPO-34 and HZSM-5 by in situ synchrotron radiation photoionization mass spectrometry (SR-PIMS). Compared with conventional methods, excellent time-resolved profiles (5 s intervals) of SR-PIMS could be obtained to study the formation and fate of HCHO and other products in the induction period, steady-state reaction period and deactivation period. The relationship between the yields of HCHO and other products in MTH reaction was directly observed. Similar formation trends of HCHO and methane, and their close correlation in yields suggest that they are mainly derived from the disproportionation of methanol on acid sites. In the presence of Y 2 O 3 , the amount of HCHO changed greatly, which further affected the hydrogen transfer processes of olefins to aromatics and aromatics to coke formation. In addition, the yield of HCHO will affect the contribution of the aromatic-based ...

Source: Angewandte Chemie - January 13, 2020 Category: Chemistry Authors: Wen W, Yu S, Zhou C, Ma H, Zhou Z, Cao C, Yang J, Xu M, Qi F, Zhang G, Pan Y Tags: Angew Chem Int Ed Engl Source Type: research