典型的生物質如木材和草等由木質素（20%），纖維素（50%）和半纖維素（25%）三種成分組成,。其中的木質素是由酚類組成的聚合物,，它是最穩(wěn)定的，最難被生物和熱轉化方法降解,。同時,，它是纖維酒精和造紙廠的廢物，因而了解它的循環(huán)和利用很有意義,。最近日本東北大學Adschiri的研究組發(fā)現(xiàn)在高溫熱水中（400 °C）如加入苯酚,，99%的木質素能降解為酚油，即使反應2小時這些酚油也沒有重新聚合為固體,。但是人們并不清楚,，這些反應是否為均相反應，反應是何種路徑,。
中科院西雙版納熱帶植物園生物質能源小組方真研究員與日本東北大學和加拿大薩斯喀徹溫大學合作發(fā)現(xiàn)：當加入苯酚后木質素能完全溶解于高壓熱水,，這大大促進木質素水解為酚油,，而苯酚的加入可防止水解后的酚油重新聚合。在研究論文中,，闡明了木質素在高壓熱水中在均相和非均相條件下降解反應的路徑和機理,。根據(jù)此反應路徑，木質素能完全降解為酚油,，并可進一步加工為生物塑料,，化學品和生物燃料。
生物谷推薦原始出處:
(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.
