A Broad-Spectrum Catalyst for Aliphatic Polymer Breakdown

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: May 13, 2025

Thermolysis of the well-defined aluminum fluoroalkoxide supported on silica (≡SiOAl(OC(CF3)3)2(O(Si≡)2), 1, 0.20 mmolAl g-1) at 200 °C forms a fluorinated amorphous silica-alumina (F-ASA) containing distribution Al(IV), Al(V), and Al(VI) sites that maintain relatively strong Lewis acidity. Small amounts Brønsted are also present in F-ASA. Solid-state NMR studies show majority centers F-ASA not close to Si-F groups form during thermolysis. is exceptionally reactive cracking (or pyrolysis) reactions neat polymer melts. Catalyst loadings as low 2 wt % (0.017 mol aluminum) efficiently break down isotactic polypropylene, high-density polyethylene, ethylene/1-octene copolymer, postconsumer wastes. The major products this reaction hyperbranched liquid paraffins internal olefins very small aromatics. Under continuous distillation oils from mixtures, pyrolysis 50 g scales feasible. cokes deactivates but can be reactivated by calcination air. These properties complementary other state-of-the-art catalysts for breakdown, unlike those does require an additional cofed reactant (e.g., H2, olefin, etc.) drive reaction.

Language: Английский

Selective conversion of aqueous sorbitol to sorbitan by amorphous Silica-Alumina catalysts

Chemical Engineering Journal, Journal Year: 2025, Volume and Issue: unknown, P. 161918 - 161918

Published: March 1, 2025

Language: Английский