LAUSR

Biomass pyrolysis has become one of the promising technologies for fuel and fine chemical production. Cellulose constitutes the main body of plant biomass and may serve as a stereochemically pure reservoir to obtain active reagents for the synthesis of biologically active substances and structural units of valuable chemical substances. This study investigated the effect of cadmium (Cd) and tin (Sn) modified mesoporous sieve R-MCM-41 (R: Cd or Sn) on the pyrolysis of cellulose via thermogravimetric analysis (TGA) and pyrolysis coupled with gas chromatography/mass spectrometry (Py-GC/MS). The Si/R molar ratio of metal modified catalysts was between 100:1 and 10:1. TGA showed that Cd- and Sn-modified MCM-41 can effectively promote the degradation of cellulose, which was almost completely volatilized at 650 °C under the catalysis of Cd-MCM-41(50) and Sn-MCM-41(50). Py-GC/MS tests were carried out with different R-MCM-41s, reaction temperatures of 450 °C, 550 °C, and 650 °C, and the cellulose-to-catalyst ratios of 5:1, 1:1, and 1:5. The use of Sn-MCM-41 promoted the formation of glycolaldehyde and a limited amount of 1,2-cyclopentanedione and 5-methylfurfural. Cd-MCM-41 catalyzed pyrolysis produced higher levels of 5-hydroxymethylfurfural, 1-hydroxy-3,6-dioxabicyclo[3.2.1]octan-2-one (LAC), 2,5-dimethyl-4-hydroxy-3(2H)-furanone, 2-hydroxy-3-methyl-2-cyclopenten-1-one, 1,2-cyclopentanedione, 3-methyl-2,4(3H,5H)-furandione, furfural, hydroxyacetone, glycolaldehyde, and butanone. When the pyrolysis temperature increased from 450 °C to 650 °C, the content of most small-molecule chemicals in the products increased by 1.8–4.1 times. When applying over-dosage of Cd-MCM-41(50) in the pyrolysis, anhydrosugars were completely degraded and dehydration/decarbonylation reactions were extensively enhanced, resulting in major products of butanone, furfural, and 5-methylfurfural. The possible reaction mechanism was proposed.