Hydrolysis lignin (HL) refers to a lignin‐rich residue obtained after the enzymatic hydrolysis of biomass. It is recalcitrant, heterogeneous, insoluble in most common solvents, and less reactive than other lignins. To enhance the reactivity of HL, a novel environmentally friendly depolymerization approach was demonstrated to produce depolymerized hydrolysis lignin (DHL) using Kraft cooking liquor, white liquor (WL) – recoverable by the Kraft recovery cycle. The effects of various process parameters such as reaction time, WL/HL ratio, and reaction temperature on lignin depolymerization were investigated using a 2 L Parr reactor under N₂. The DHLs obtained were then characterized by Gel permeation chromatography (GPC)‐Ultraviolet Detector (GPC‐UV), ³¹P Nuclear Magnetic Resonance (NMR) spectroscopy, and ultraviolet visible (UV–visible) spectroscopy, while the filtrates were characterized by high‐performance liquid chromatography (HPLC) for saccharinic acids. The DHL yield reached 45–70% from the treatments at 150–190 °C for 1 h at a WL/HL mass ratio of 1:4 ~ 2:1. The weight‐average molecular weight (M_w) value of the DHL obtained at 190 °C after treatment for 1 h at a WL/HL ratio of 2:1 (w/w) was 2600 Da. Moreover, a significant increase in non‐condensed phenolic hydroxyl and carboxylic acid group content was observed with decreasing M_w. Compared with various existing lignin modification approaches, the approach reported here is less expensive and more environmentally friendly if integrated into Kraft pulp mill operations with the residual WL from the lignin depolymerization process being recycled to the mill chemical recovery cycle. Process scale‐up was also demonstrated using a 20 L circulating reactor. In this case, the M_w of the DHL produced after treatment at 170 °C for 2 h was 2400 Da. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd.

中文翻译：

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使用牛皮纸蒸煮液解水解木质素的新型环保方法：可通过牛皮纸回收循环回收的化学物质

水解木质素（HL）是指生物质酶水解后获得的富含木质素的残基。它具有顽强性，不均一性，不溶于大多数普通溶剂，并且比其他木质素的反应性差。为了提高HL的反应性，一种新颖的环保解聚方法被证明可以使用牛皮纸蒸煮液，白液（WL）生产可解聚的水解木质素（DHL），可通过牛皮纸回收周期进行回收。使用2 L Parr反应器在N ₂下研究了反应时间，WL / HL比和反应温度等各种工艺参数对木质素解聚的影响。然后通过凝胶渗透色谱（GPC）-紫外检测器（GPC-UV）对获得的DHL进行表征，³¹P核磁共振（NMR）光谱和紫外可见（UV-visible）光谱，而滤液用糖精酸的高效液相色谱（HPLC）表征。在WL / HL质量比为1：4〜2：1的情况下，在150-190°C的温度下处理1小时，DHL的收率达到45-70％。的重均分子量（M_瓦特在190℃以2:1的WL / HL比率获得的DHL的）值处理后1个小时：1（重量/重量）为2600道尔顿。此外，随着M _w的降低，未缩合的酚羟基和羧酸基团含量也显着增加。。与各种现有的木质素改性方法相比，如果将其整合到牛皮纸制浆厂的操作中，并将木质素解聚过程中产生的残留WL再循环到工厂的化学回收周期中，则此处报告的方法将更便宜且对环境更友好。还证明了使用20 L循环反应器进行工艺放大。在这种情况下，在170°C处理2小时后产生的DHL的M _w为2400 Da。©2020年化学工业协会和John Wiley＆Sons，Ltd.