典型的生物质如木材和草等由木质素（20%），纤维素（50%）和半纤维素（25%）三种成分组成。其中的木质素是由酚类组成的聚合物，它是最稳定的，最难被生物和热转化方法降解。同时，它是纤维酒精和造纸厂的废物，因而了解它的循环和利用很有意义。最近日本东北大学Adschiri的研究组发现在高温热水中（400 °C）如加入苯酚，99%的木质素能降解为酚油，即使反应2小时这些酚油也没有重新聚合为固体。但是人们并不清楚，这些反应是否为均相反应，反应是何种路径。
中科院西双版纳热带植物园生物质能源小组方真研究员与日本东北大学和加拿大萨斯喀彻温大学合作发现：当加入苯酚后木质素能完全溶解于高压热水，这大大促进木质素水解为酚油，而苯酚的加入可防止水解后的酚油重新聚合。在研究论文中，阐明了木质素在高压热水中在均相和非均相条件下降解反应的路径和机理。根据此反应路径，木质素能完全降解为酚油，并可进一步加工为生物塑料，化学品和生物燃料。
生物谷推荐原始出处:
(Bioresource Technology)，Volume 99, Issue 9, June 2008, Pages 3424-3430，Zhen Fang, Janusz A. Kozinski
Reaction chemistry and phase behavior of lignin in high-temperature and supercritical water
Zhen Fanga , Takafumi Satob, Richard L. Smith Jr.b, , Hiroshi Inomatab, Kunio Araib and Janusz A. Kozinskic
Abstract
Decomposition of organosolve lignin in water/phenol solutions was studied in a 50 nL micro-reactor coupled with optical, Raman and infrared microscopies at temperatures up to 600 oC and water densities up to 1165 kg/m3. It was found that when phenol was used with {lignin + water} mixtures that a homogenous phase was formed that seemed to promote the decomposition of lignin into phenolic fragments by hydrolysis and pyrolysis. Phenol, along with the homogenous reaction conditions also inhibited re-polymerization of the phenolics and promoted oil formation. On the other hand, in the absence of phenol, lignin remained as a heterogeneous phase with water over the range of conditions studied. The homogeneous conditions and conditions for inhibiting char formation by phenol were elucidated and it was found that mixtures of phenol and lignin become homogeneous at 400–600 °C and high water densities of 428–683 kg/m3, corresponding to maximum pressures of 93 MPa. These results were further used to propose reaction paths.
