An economically viable ionic liquid for the fractionation of lignocellulosic biomass
An economically viable ionic liquid for the fractionation of lignocellulosic biomass
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DOI：
10.1039/c7gc00705a
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发表时间：
2017-07-07
期刊：
影响因子：
9.8
通讯作者：
Hallett, Jason P.
中科院分区：
文献类型：
--
作者：
Brandt-Talbot, Agnieszka;Gschwend, Florence J. V.;Hallett, Jason P.
木质纤维素生物质的成本有效的分级（预处理）是必要的，以使其能够大规模用作液体燃料、生物基材料和生物衍生化学品的来源。虽然许多离子液体（IL）已被证明能够高效预处理，但其高成本对商业可行性构成障碍。在这项研究中，我们详细调查了低成本（约。$1kg（-1））离子液体三乙基硫酸氢铵，用于将芒草分级分离成富含纤维素的纸浆、木质素和馏出物。我们发现，高达85%的木质素和高达100%的半纤维素溶解到IL溶液中。半纤维素主要以单体形式溶解，戊糖部分转化为糠醛。高达77%的生物质中所含的葡萄糖可以通过纸浆的酶糖化释放。IL被成功回收并重复使用了四次。每次IL回收率均达到99%。在回收过程中保持了有效的木质素去除和高糖化产率，这首次证明了由于不可降解溶剂的自清洁特性，重复使用IL是可行的。我们进一步证明，糠醛和乙酸可以通过简单蒸馏从非挥发性IL中定量分离，提供易于回收的有价值的副产物流，而未检测到IL降解产物。我们还包括葡萄糖，半纤维素和木质素的详细质量平衡，以及分馏过程的初步技术经济估计。这是第一次证明了一个有效的和重复的木质纤维素分级与真正低成本的IL，并开辟了一条道路，以经济上可行的IL为基础的预处理工艺。
Cost-effective fractionation (pretreatment) of lignocellulosic biomass is necessary to enable its large-scale use as a source of liquid fuels, bio-based materials and bio-derived chemicals. While a number of ionic liquids (ILs) have proven capable of highly effective pretreatment, their high cost presents a barrier to commercial viability. In this study, we investigate in detail the application of the low-cost (ca. $1 kg(-1)) ionic liquid triethylammonium hydrogen sulfate for the fractionation of the grass Miscanthus x giganteus into a cellulose rich pulp, a lignin and a distillate. We found that up to 85% of the lignin and up to 100% of the hemicellulose were solubilized into the IL solution. The hemicellulose dissolved mainly in monomeric form, and pentoses were partially converted into furfural. Up to 77% of the glucose contained in the biomass could be released by enzymatic saccharification of the pulp. The IL was successfully recovered and reused four times. A 99% IL recovery was achieved each time. Effective lignin removal and high saccharification yields were maintained during recycling, representing the first demonstration that repeated IL use is feasible due to the self-cleaning properties of the non-distillable solvent. We further demonstrate that furfural and acetic acid can be separated quantitatively from the non-volatile IL by simple distillation, providing an easily recoverable, valuable co-product stream, while IL degradation products were not detected. We further include detailed mass balances for glucose, hemicellulose and lignin, and a preliminary techno-economic estimate for the fractionation process. This is the first demonstration of an efficient and repeated lignocellulose fractionation with a truly low-cost IL, and opens a path to an economically viable IL-based pretreatment process.