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Rapid Depolymerization of Decrystallized Cellulose to Soluble Products via Ethanolysis under Mild Conditions.
ChemSusChem ( IF 7.5 ) Pub Date : 2020-03-01 , DOI: 10.1002/cssc.201903446
Maksim Tyufekchiev 1 , Katherine Ralph 1 , Pu Duan 2 , Shichen Yuan 2 , Klaus Schmidt-Rohr 2 , Michael T Timko 1
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Efficient cellulose depolymerization is a major bottleneck for economical production of second-generation biofuels. In this work, crystalline cellulose was subjected to sequential ball milling and ethanolysis as a mild and selective depolymerization approach. Ball milling and ethanolysis resulted in 38±1 % cellulose conversion, with 24 % ethyl-glucopyranoside as the main identified and quantified product and negligible side reaction of the ethanol solvent to form diethyl ether. In comparison, ethanolysis of the original cellulose resulted in only 3±1 % conversion. Additional soluble products from cellulose ethanolysis included carbohydrate isomers and oligomers, differing from the products obtained from hydrolysis. X-ray diffraction and nuclear magnetic resonance spectroscopy revealed increased crystallinity post-reaction, retarding further depolymerization. Hot liquid water extracted soluble oligomers from the ethanolyzed cellulose, suggesting formation of a nanoscale barrier of crystalline cellulose that traps soluble products during ethanolysis. Use of cellulose-swelling co-solvents and repeated mechanical decrystallization both proved effective at increasing cellulose conversion and soluble product yields. Repeated ball milling and ethanolysis resulted in 62±1 % cellulose conversion. Ethanolysis of decrystallized cellulose has potential for rapid (<2 h) de-polymerization at mild conditions.

中文翻译:

在温和条件下,通过乙醇分解将结晶纤维素快速解聚为可溶性产物。

高效的纤维素解聚是经济生产第二代生物燃料的主要瓶颈。在这项工作中,作为温和的选择性解聚方法,对结晶纤维素进行了连续球磨和乙醇分解。球磨和乙醇分解导致38±1%的纤维素转化率,其中24%的乙基-吡喃葡萄糖苷是主要鉴定和定量的产物,乙醇溶剂形成二乙醚的副反应可忽略不计。相比之下,原始纤维素的乙醇化仅产生3±1%的转化率。来自纤维素乙醇解的其他可溶产物包括碳水化合物异构体和低聚物,不同于水解获得的产物。X射线衍射和核磁共振波谱显示反应后结晶度增加,阻碍进一步解聚。热水从乙醇化的纤维素中提取可溶性低聚物,表明形成了结晶纤维素的纳米级屏障,该屏障在乙醇化过程中捕获了可溶性产物。纤维素溶胀助溶剂的使用和重复的机械去结晶均证明可有效提高纤维素转化率和可溶性产物收率。重复球磨和乙醇分解导致纤维素转化率为62±1%。在温和的条件下,对结晶纤维素的乙醇水解具有快速(<2小时)解聚的潜力。纤维素溶胀助溶剂的使用和重复的机械去结晶均证明可有效提高纤维素转化率和可溶性产物收率。重复球磨和乙醇分解导致纤维素转化率为62±1%。在温和的条件下,对结晶纤维素的乙醇水解具有快速(<2小时)解聚的潜力。纤维素溶胀助溶剂的使用和重复的机械去结晶均证明可有效提高纤维素转化率和可溶性产物收率。重复球磨和乙醇分解导致纤维素转化率为62±1%。在温和的条件下,对结晶纤维素的乙醇水解具有快速(<2小时)解聚的潜力。
更新日期:2020-03-01
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