微波辅助杨木快速苯酚液化及产物表征  

Rapid Wood Liquefaction with Phenol by Microwave Heating and Product Characterization

作　　者：李改云[1] 朱显超 邹献武[1] 向琴[1] 何玉婵[1] 

机构地区：[1]中国林业科学研究院木材工业研究所,北京100091

出　　处：《林业科学》2014年第11期115-121,共7页Scientia Silvae Sinicae

基　　金：国家林业局"948"项目(2012-4-28)

摘　　要：针对传统木材苯酚液化技术中存在的反应时间长、产物黏度高和反应活性降低等问题，采用微波加热方式，将杨木木粉在酸化苯酚溶剂中进行快速解聚反应。结果表明，微波加热条件下杨木苯酚液化的适宜条件为：木粉含水率30%～40%，液化时间15 min，苯酚与木粉的比例（P/W）2.5，木粉粒径0.18～0.25 mm，在此条件下木材液化率达到87%。微波加热的木材苯酚液化速率比传统油浴加热提高至少6倍。木材被降解为醇类、酸类、醚类、醛类和酚类等低分子质量物质，液化产物黏度显著降低，仅为3015 mPa·s，且与甲醛的反应活性较高，100 g液化产物反应消耗的甲醛达2.1 mol。微波加热与传统加热下的木材苯酚液化反应历程不尽相同，主要表现在纤维素和半纤维素降解为单糖后，单糖可进一步断裂为2，3-丁二醇、1，2-丙二醇、乙二醇和乙二醛等物质，这些物质相互之间可以发生脱水、羟醛缩合等反应进一步生成 2-乙氧基-丙烷，1，1-二乙氧基-乙烷、二异丙基缩甲醛和12-冠醚-4。A method for fast poplar wood liquefaction in phenol by using microwave energy was successfully developed. The optimum conditions for microwave-assisted poplar wood liquefaction in phenol are as follows： moisture content 30% -40%,reaction time 15 min,phenol to wood （P/W） ratio 2. 5,wood powder diameter 0. 18 -0. 25 mm,and liquefaction yield 87%. It was proved that microwave improved the liquefaction rate at least 6 times faster than conventional heating. Wood was degraded to low molecular weight substances including alcohols, acids, ether, aldehyde and phenolic compounds. Viscosity of liquefied wood products was remarkably decreased from 8 250 mPa·s to 3 015 mPa＆#183;s. And 100 g of liquefied wood reacted with about 2. 1 mol of formaldehyde. There were only seven main conpounds,including phenol,2,3-butanediol,1,2-propanediol,2-ethoxy-propane,1,1-diethoxy-ethane,diisopropyl formal and 12-crown-4 in diethyl ether-soluble portions from liquefied wood products. It was concluded that the reaction mechanism was somewhat different between microwave-assisted and traditional wood phenolation. Cellulose and hemicellulose were firstly degraded into monosaccharides. And monosaccharides could be further cracked into 2,3-butanediol,1,2-propanediol,ethylene glycol and ethanedial,and so on. These substances reacted with each other and converted to 2-ethoxy-propane,1,1-diethoxy-ethane,diisopropyl formal and 12-crown-4.

关 键 词：微波加热 杨木 苯酚液化 产物表征 

分 类 号：TQ351[化学工程]