Energetics of cellulose and cyclodextrin glycosidic bond cleavage. Issue 2 (13th January 2017)

• Record Type: Journal Article
• Authors: Zhu, Cheng; Krumm, Christoph; Facas, Gregory G.; Neurock, Matthew; Dauenhauer, Paul J.
• Is Part Of: Reaction chemistry & engineering. Volume 2:Issue 2(2017)
• Page Start: 201
• Page End: 214
• Publication Date: 2017-01-13
• Subjects: Reaction mechanisms (Chemistry) -- Periodicals; Chemical engineering -- Periodicals; Chemical engineering; Reaction mechanisms (Chemistry); Periodicals; 547.705
• DOI: 10.1039/c6re00176a
• Languages: English
• ISSNs: 2058-9883

Abstract

Abstract : Thermochemical conversion of lignocellulosic materials for production of biofuels and renewable chemicals utilizes high temperature to thermally decompose long-chain cellulose to volatile organic compounds. Abstract : Thermochemical conversion of lignocellulosic materials for production of biofuels and renewable chemicals utilizes high temperature to thermally decompose long-chain cellulose to volatile organic compounds. Cellulose undergoes two distinct kinetic regimes of intra-chain scission: low-temperature glycosidic bond cleavage ( T < 467 °C) associated with a low apparent activation energy and high-temperature glycosidic bond cleavage ( T > 467 °C) associated with a high apparent activation energy. In this work, the initial breakdown kinetics of cellulose were examined from 385 °C to 505 °C using a millisecond, thin-film reactor called PHASR (pulse-heated analysis of solid/surface reactions). Using the cellulose surrogate, α-cyclodextrin, the energetics of each kinetic regime were characterized by measuring the conversion between 20 ms and 2.0 seconds. The low temperature kinetic regime exhibited glycosidic bond cleavage ( E a, 1 = 23.2 ± 1.9 kcal mol −1, k 0, 1 = 2.0 × 10 7 s −1 ), while the high temperature kinetic regime ( E a, 2 = 53.7 ± 1.1 kcal mol −1, k 0, 2 = 2.4 × 10 16 s −1 ) was consistent with four reaction mechanisms including concerted transglycosylation. Apparent energetics were compared with computed literature values.