Study on the influence of channel structure properties in the dehydration of glycerol to acrolein over H-zeolite catalysts

Systematic studies have been conducted over several selected H-zeolites, namely HZSM-5, H-Beta, HY, nano HZSM-5, HZSM-11 and nano HZSM-11, aimed to investigate influence of the channel structure on catalytic performance for gas phase dehydration of glycerol to acrolein. Compared to H-Beta and HY, improved catalytic performance was discovered over HZSM-5, which demonstrated that H-zeolites with smaller channels, the ones marginally larger than the molecular diameter of glycerol, were preferential for the reaction. HZSM-11, with lower channel complexity, was more likely to obtain superior catalytic performance due to enhanced diffusion. Nano HZSM-11 (300–500 nm) exhibited excellent catalytic performance with 81.6 mol% glycerol conversion and 74.9 mol% acrolein selectivity at GHSV as high as 873 h−1 (TOS = 8 h). BET and TEM experiment results indicated that coke was initially deposited at channel intersections of H-zeolites, and when the channel blockage came up to a certain extent, there arrived the onset of coke deposition on the external surface.

Figure optionsDownload high-quality image (152 K)Download as PowerPoint slideHighlights
► H-zeolites with smaller channels favored glycerol dehydration to acrolein.
► HZSM-11 exhibited superior catalytic performance than HZSM-5.
► The introduction of carrier gas could improve catalytic performance of H-zeolites.
► Coke was initially deposited at channel intersections of H-zeolites.
► External surface of H-zeolites supplied room for coke deposition during reaction.