Switchgrass was fractionated using maleic acid (MA) as an acid hydrotrope in comparison with p-toluenesulfonic acid (p-TsOH) at atmospheric pressure. MA achieved more rapid and greater maximal dissolution of lignin and hemicelluloses (88 % and 63 %, respectively) than did p-TsOH (73 % and 55 %, respectively). MA esterified (carboxylated) the dissolved acid hydrotropic lignin (AHL) as evidenced by 2D ¹H-¹³C HSQC NMR analysis, which improved AHL antioxidant ability compared with AHL from p-TsOH that is not carboxylated. MA also carboxylated the lignin and cellulose in the fractionated cellulosic water-insoluble solids (WIS), which significantly improved WIS enzymatic digestiblity for sugar production than did p-TsOH with the same level of delignification. It also improved the lignin lubrication effect to facilitate mechanical fibrillation of WIS into lignocellulosic nanofibrils. MA is an FDA-approved indirect food additive (21CFR175-177) with lower acidity and solubility than p-TsOH, which substantially benefits recycling and decreasing environmental impacts to achieve sustainability.

与对-甲苯磺酸（p- TsOH）相比，在大气压下使用马来酸（MA）作为酸水溶助剂来分离柳枝。与p -TsOH（分别为73％和55％）相比，MA可以更快，更大程度地分解木质素和半纤维素（分别为88％和63％）。通过2D ¹ H- ¹³ C HSQC NMR分析证明，MA酯化（羧化了）溶解的酸性亲水木质素（AHL），与来自p的AHL相比，提高了AHL的抗氧化能力-TsOH未羧基化。MA还使纤维素水不溶性固体分馏物（WIS）中的木质素和纤维素羧化，与相同脱木质素水平的p- TsOH相比，MAS显着改善了WIS的酶促消化性。它还改善了木质素润滑效果，有助于WIS机械原纤化为木质纤维素纳米原纤维。MA是FDA批准的间接食品添加剂（21CFR175-177），其酸度和溶解度低于对-TsOH，可大大有利于回收利用并减少对环境的影响，以实现可持续性。