Hydrolytic Cleavage of 尾-O-4 Ether Bonds of Lignin Model Compounds in an Ionic Liquid with Metal Chlorides

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• 作者：Songyan Jia ; Blair J. Cox ; Xinwen Guo ; Z. Conrad Zhang ; John G. Ekerdt
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2011
• 出版时间：January 19, 2011
• 年：2011
• 卷：50
• 期：2
• 页码：849-855
• 全文大小：261K
• 年卷期：v.50,no.2(January 19, 2011)
• ISSN：1520-5045

文摘

The hydrolytic cleavage of 尾-O-4 ether bonds in lignin model compounds, guaiacylglycerol-尾-guaiacyl ether (GG) and veratrylglycerol-尾-guaiacyl ether (VG), was studied in 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) with metal chlorides and water. FeCl₃, CuCl₂, and AlCl₃ were found to be effective and functioned catalytically in cleaving the 尾-O-4 bond of GG, although a number of other metal chlorides are considerably less active. AlCl₃ functioned more effectively in cleaving the 尾-O-4 bond of VG than did FeCl₃ and CuCl₂. After 120 min at 150 掳C, GG conversion reached 100%, and about 70% of the 尾-O-4 bonds of GG were hydrolyzed, liberating guaiacol, in the presence of FeCl₃ and CuCl₂, while about 80% of the 尾-O-4 bonds of GG were hydrolyzed in the presence of AlCl₃ with 100% GG conversion. About 75% of the 尾-O-4 bonds of VG were hydrolyzed in the presence of AlCl₃ after 240 min at 150 掳C. The catalytic activity is associated with the hydrochloric acid, working as the acid catalyst, formed in situ by the hydrolysis of the metal chlorides. A dehydration product and dimer products from GG were detected and proposed as the possible intermediate products in the GG reaction. One possible acid-catalyzed pathway accounting for the guaiacol production from GG is presented.