We examined wood liquefaction using phenol and mixed acid catalysts with microwave heating, and compared that with similar processes that use oil bath heating. The reaction time for microwave heating to achieve a resi...We examined wood liquefaction using phenol and mixed acid catalysts with microwave heating, and compared that with similar processes that use oil bath heating. The reaction time for microwave heating to achieve a residue content was one sixth, one eighteenth, and one twenty-fourth of that from oil bath heating, respectively, for phenol to wood （P/W） ratios of 2.5/1, 2/1 and 1.5/1. A low P/W ratio tended to result in carbonization of liquefied wood due to an insufficient amount of phenol and localized microwave superheating. Fourier transform infrared spectroscopic （FTIR） evaluation of the liquefied residue, showed that the liquefaction rates of wood com- ponents differed. Hemicellulose was most susceptible to liquefaction, crystalline cellulose was most recalcitrant, and guaiacyl units the most prone to re-condensation. From FTIR, the chemical components and substitution patterns of bonded phenol were similar for both methods.展开更多
Concise and efficient three-component domino [4＋ 1 ＋ 1] carbocyclization to highly substituted fluoren-9-one derivatives promoted by K2CO3 has been developed under microwave irradiation conditions. The direct bis-cy...Concise and efficient three-component domino [4＋ 1 ＋ 1] carbocyclization to highly substituted fluoren-9-one derivatives promoted by K2CO3 has been developed under microwave irradiation conditions. The direct bis-cyanation and aryl amination residing in fluoren-9-one framework were achieved in a one-pot operation. The reaction proceeds at fast rates and can be finished within 30 min, which makes workup convenient to give good to excellent chemical yields.展开更多
基金financially supported by the ‘‘948Project’’ of State Forestry Administration(2012-4-28)
文摘We examined wood liquefaction using phenol and mixed acid catalysts with microwave heating, and compared that with similar processes that use oil bath heating. The reaction time for microwave heating to achieve a residue content was one sixth, one eighteenth, and one twenty-fourth of that from oil bath heating, respectively, for phenol to wood （P/W） ratios of 2.5/1, 2/1 and 1.5/1. A low P/W ratio tended to result in carbonization of liquefied wood due to an insufficient amount of phenol and localized microwave superheating. Fourier transform infrared spectroscopic （FTIR） evaluation of the liquefied residue, showed that the liquefaction rates of wood com- ponents differed. Hemicellulose was most susceptible to liquefaction, crystalline cellulose was most recalcitrant, and guaiacyl units the most prone to re-condensation. From FTIR, the chemical components and substitution patterns of bonded phenol were similar for both methods.
文摘Concise and efficient three-component domino [4＋ 1 ＋ 1] carbocyclization to highly substituted fluoren-9-one derivatives promoted by K2CO3 has been developed under microwave irradiation conditions. The direct bis-cyanation and aryl amination residing in fluoren-9-one framework were achieved in a one-pot operation. The reaction proceeds at fast rates and can be finished within 30 min, which makes workup convenient to give good to excellent chemical yields.
