Dilute Acid Hydrolysis of Loblolly Pine: A Comprehensive Approach

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• 作者：Teresita Marzialetti ; Mariefel B. Valenzuela Olarte ; Carsten Sievers ; Travis J. C. Hoskins ; Pradeep K. Agrawal ; Christopher W. Jones
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2008
• 出版时间：October 1, 2008
• 年：2008
• 卷：47
• 期：19
• 页码：7131-7140
• 全文大小：262K
• 年卷期：v.47,no.19(October 1, 2008)
• ISSN：1520-5045

文摘

A comprehensive study of the acid hydrolysis of the softwood species, Loblolly pine (Pinus taeda), using different hydrolysis conditions is presented. The effect of the type of acid, pH, reaction temperature, and reaction time on hydrolysis products such as monosaccharides (mannose, glucose, galactose, xylose, and arabinose) and the subsequent degradation products, 5-hydroxymethyl-2-furaldehyde (HMF) and 2-furaldehyde (furfural) is reported using a batch reactor. Trifluoroacetic acid (TFA) is found to yield the highest amount of overall soluble monosaccharides (∼70% yield from the hemicelluloses fraction) at 150 °C at pH 1.65. The mineral acids (HCl, H₂SO₄, HNO₃, and H₃PO₄) gave a slightly lower yield of monosaccharides from hydrolyzed hemicellulose (∼60%). At 200 °C, cellulose is hydrolyzed by the mineral acids as evidenced by higher levels of solid dissolution and higher soluble hexose (relative to pentose) yields. Larger amounts of degradation products are also noted at higher temperatures. Furthermore, an increased amount of HMF and furfural is noted in the liquid product as compared to lower temperatures. TFA was found to be the most “gentle” acid, leading to limited monosaccharide degradation among the acids used. The presence of soluble oligosaccharides in solution after hydrolysis was confirmed by applying a secondary acid hydrolysis to the solid-free liquid hydrolysate. Good closure of mass balances was possible using total organic carbon (TOC) analysis.