Observation and Characterization of Cellulose Pyrolysis Intermediates by 13C CPMAS NMR. A New Mechanistic Model

Autor:	Jan B. Wooten, Mohammad R. Hajaligol, and Jeffrey I. Seeman
Rok vydání:	2003
Předmět:	chemistry.chemical_classification Ketone General Chemical Engineering Energy Engineering and Power Technology Carbohydrate Spectral line Amorphous solid chemistry.chemical_compound Fuel Technology chemistry Physical chemistry Organic chemistry Char Cellulose Spinning Pyrolysis
Zdroj:	Energy & Fuels. 18:1-15
ISSN:	1520-5029 0887-0624
DOI:	10.1021/ef0300601
Popis:	The composition of char from heated Avicel cellulose was monitored as a function of heating time and temperature, using 13C cross-polarization magic-angle spinning (CPMAS) NMR. Complex NMR line shapes observed in the carbohydrate region of the spectra are indicative of the presence of multiple carbohydrate forms. By successive spectral subtractions of the 300 °C pyrolysis char, the complex line shapes were separated into three distinct carbohydrate components that correspond to the crystalline cellulose starting material (SM), an intermediate cellulose (IC) that resembles a low degree-of-polymerization (low-DP) amorphous cellulose, and a disordered final carbohydrate (FC) that is characterized by a very broad 13C line width. Curve fitting was used to monitor the changes in the approximate abundance of these different carbohydrate forms relative to the aliphatic, aromatic, carboxyl, and ketone clusters of compounds of the char. The time evolution of the IC, together with its spectral line shapes, associate...
Databáze:	OpenAIRE
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