苯酚液化是木质纤维素液化的重要手段。木质纤维素是不均一的原料，而完全液化研究将其看作是“单一”的原料。针对这一问题本文以秸秆为原料，采用选择性液化的方式对其进行了苯酚液化，并针对固体产物和液体产物分别进行了应用研究。 针对秸秆原料不均一的特点，采用选择性液化的方式对秸秆进行了液化研究，并比较了选择性液化与完全液化。结果表明：低温下适当的浓硫酸用量、较高的苯酚用量、适当的反应时间有利于保留纤维素而选择性液化半纤维素和木质素，选择性液化条件优化表明在浓硫酸用量为（占总反应体系的比例）3 %，反应温度100 ℃，反应时间30 min，苯酚/秸秆用量（w/w）3，选择性液化达到最佳效果，此时秸秆中纤维素保留率达70 %，而液化产物结合酚含量可达100 %。与完全液化相比，选择性液化反应条件温和，并且保留了大量的纤维素，大大提高了原料利用价值。 利用苯酚选择性液化特点，将其作为秸秆组分分离和增强底物纤维素酶酶解的手段，实现了秸秆组分的有效分离，提高了底物纤维素酶酶解效果。苯酚选择性液化使得秸秆中大量的木质素和半纤维素液化，而保留了纤维素，低温（100 ℃左右），H2SO4浓度3 %～4 %，苯酚/秸秆用量为3～4条件下，苯酚选择性液化可在20 min内快速脱除秸秆中的半纤维素和木质素（木质素脱除率≥70 %），而保留纤维素，纤维素回收率≥80 %，从而实现了秸秆组分的有效分离。苯酚选择性液化制得的预处理秸秆具有较好的纤维素酶解效果，100 ℃，H2SO4浓度3 %，苯酚/秸秆用量为3，液化时间为60min时得到的苯酚选择性液化残渣酶解率≥65 % 。 为考察苯酚选择性液化产物的实用性，文中研究了秸秆选择性液化产物的性质，并以此为原料合成了树脂类胶黏剂。结果表明：浓硫酸用量3 %，反应温度100 ℃，苯酚/秸秆用量（w/w）3时，秸秆苯酚选择性液化产物结合酚含量在0～30 min内呈直线增加趋势，30 min时结合酚含量达到100 %，30 min后液化产物结合酚含量缓慢增加，60 min时液化产物结合酚含量达到120 %。以上述30 min时得到的选择性液化产物为原料合成的树脂类胶黏剂达到GB/T 14732-2006标准。;It’s an important way to liquefy lignocelluloses with phenol. Lignocelluloses, which were regarded as homogeneous materials in complete liquefaction, are actually inhomogeneous. In this paper, wheat straw is used as raw material and a selective liquefaction way is proposed to make it liquefied, and at the mean time, application of products from the liquefaction is also being discussed. Based on the inhomogeneity of wheat straw, the selective liquefaction way was used to make it liquefied, and differences between the selective way and the complete way were compared. The results indicated that proper catalyst concentration and reaction time, higher phenol dosage with lower temperature were needed to save cellulose and liquefy hemicellulose and lignin. The optimized conditions for selective liquefaction were H2SO4 (catalyst weight to whole reaction system) 3 %, 100 ℃, 30 min, and phenol/straw ratio 3, in this condition, the recovery content of cellulose was above 70 %, and the combined phenol-to-yield can reach 100 %. Moreover, compared with complete liquefaction, the selective liquefaction, which was more gentle, can rescue cellulose in order to elevate the value of raw material. Based on the characters of selective liquefaction, it can be used as a way for fraction separation and enhancing its enzymatic hydrolysis of wheat straw. The selective liquefaction, where large amounts of lignin and hemicellulose were liquefied with cellulose retained, was suitable for fraction separation, in the case of that 100 ℃, sulfuric acid concentration 3 %～4 %, phenol/straw ratio 3～4, lignin and hemicellulose can be liquefied in 20 min, where the removal content of lignin is above 70 % and the recovery content of cellulose is above 80 %. Furthermore, the unliquefied residues obtained in the selective liquefaction have high susceptibility of enzymatic digestion, enzymatic hydrolysis yields of residues, obtained at 100 ℃, sulfuric acid concentration 3 %, phenol/straw ratio 3 for 60 min, can be as high as 65 % in 48 h. In order to make the liquefied products more practical, properties of the liquefied products have been discussed and phenol-formaldehyde type adhesives have been synthesized from that. Results showed that in the case of 100 ℃, sulfuric acid concentration 3%, and phenol/straw ratio (w/w) 3, the combined phenol-to-yield content of liquefied products was increasing linearly in the initial 30 min, and it could achieve 100 % at 30 min. However, the combined phenol-to-yield content of liquefied products was increasing slowly after that and it could get 120 % at 60 min. In addition, adhesives synthesized from the liquefied products obtained at 30 min could meet the standard of GB/T 14732-2006.</p
