Depolymerisation of cellulose is a critical step for biomass-based bio-refining processes to produce valuable chemicals. Herein, we propose the mechanism of the promoting effect of NaCl on the cellulose hydrolysis process based on a systematic kinetic study involving variable temperature studies and the use of deuterated agents. It has been found that the presence of NaCl simultaneously enhances the generation of acidic products from cellulose decomposition and pushes the generated protons to the surface of cellulose, dramatically increasing surface acidity and facilitating the autocatalytic hydrolysis of cellulose. Cl⁻ disrupted the intermolecular hydrogen bonding of cellulose, especially in the first surface layer. Thus, the solid cellulose chains were peeled off layer-by-layer, leading to an accelerated hydrolysis of cellulose by the adsorbed protons. Without the need for traditional acidic catalysts, this autocatalytic depolymerisation of cellulose in water, assisted by salt provides a practically viable route to the enhanced conversion of biomass to chemicals.

中文翻译：

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对纤维素的盐辅助自催化水解的机理理解†

纤维素的解聚是基于生物质的生物精炼过程生产有价值的化学药品的关键步骤。在此，我们基于涉及可变温度研究和使用氘代剂的系统动力学研究，提出了氯化钠对纤维素水解过程的促进作用的机理。已经发现NaCl的存在同时增强了纤维素分解产生的酸性产物的产生，并将产生的质子推至纤维素的表面，极大地增加了表面酸性，并促进了纤维素的自催化水解。氯^-破坏了纤维素的分子间氢键，特别是在第一表面层中。因此，固体纤维素链被一层一层地剥离，导致纤维素被吸附的质子加速水解。不需要传统的酸性催化剂，纤维素在水中的自动催化解聚，辅以盐，为提高生物量向化学物质的转化提供了切实可行的途径。