摘要
以蔗渣为原料,采用碱氧预处理法从蔗渣中分离纤维素和木质素,分析碱氧作用机理,并酸解预处理得到的纤维素制备乙酰丙酸,考察了不同预处理条件对后续酸解转化的影响.结果表明:蔗渣在120℃的4%NaOH/1.2%H_2O_2溶液中蒸煮4h,纤维素百分比可从46.5%提升至78.6%.NaOH和H_2O_2均能使原料中纤维素百分比提高,但作用机理有所不同.NaOH的作用是溶解蔗渣中非纤维素组分,提高纤维素所占百分比;H_2O_2的作用是氧化降解NaOH溶液中的木质素,降低溶液粘度并提高溶解能力,减少纤维素表面残留的木质素.在碱氧预处理过程中,蔗渣中的纤维素会有一定流失,并且残留的纤维素在NaOH溶液中得到了晶化,不利于后续的酸解转化,纤维素的有效转化率始终维持在35%左右.
In this paper, bagasse as raw materal has been pret reated by alkal i /hydrogen peroxide to sepa-rate cellulose and lignin, and the mechanism of alkali/hydrogen peroxide been analyzed. Then cellulose af-ter pretreatment has been converted into levulinic acid catalyzed by acid to examine the effect of alkali/hy-drogen peroxide pretreatment on acidolysis. The results show that cellulose content in bagasse pretreated in 4% NaOH/1. 2% H202 so lu t io n u n de r 120 °C fo r 4h can be inc reased from 46. 5% to 46. 5%. N aO H and H2 02 can make cellulose content increase in the raw material, but the mechanism is different. The effect of NaOH is to dissolve other components and increase cellulose content. H202 plays a role in oxida-tion degradation of lignin in NaOH solution to reduce the solution viscosity and improve the ability of dis-solution which is conducive to reducing the residual lignin on the surface of cellulose. In alkali/hydrogen peroxide pretreatment process, there is a certain loss of cellulose and the residue of cellulose is cystallized in the NaOH solution which doesn＇t benefit the follow-up of acidolysis. The effective conversion rate of cel-lulose is keeping at about 35%.
出处
《西南师范大学学报（自然科学版）》
CAS
北大核心
2017年第5期47-53,共7页
Journal of Southwest China Normal University(Natural Science Edition)
关键词
预处理
分离
纤维素
乙酰丙酸
pretreatment
separation
cellulose
levulinic acid
