Krishna Siddarth H, Walker Theodore W, Dumesic James A, Huber George W
Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin, 53706, United States.
ChemSusChem. 2017 Jan 10;10(1):129-138. doi: 10.1002/cssc.201601308. Epub 2016 Dec 13.
We studied the acid-catalyzed isomerization of levoglucosenone (LGO) to 5-hydroxymethylfurfural (HMF) and developed a reaction kinetics model that describes the experimental data across a range of conditions (100-150 °C, 50-100 mm H SO , 50-150 mm LGO). LGO and its hydrated derivative exist in equilibrium under these reaction conditions. Thermal and catalytic degradation of HMF are the major sources of carbon loss. Within the range of conditions studied, higher temperatures and shorter reaction times favor the production of HMF. The yields of HMF and levulinic acid decrease monotonically as tetrahydrofuran is added to the aqueous solvent system, indicating that water plays a role in the LGO isomerization reaction. Initial-rate analyses show that HMF is produced solely from LGO rather than from the hydrated derivative of LGO. The results of this study are consistent with a mechanism for LGO isomerization that proceeds through hydration of the anhydro bridge, followed by ring rearrangement analogous to the isomerization of glucose to fructose.
我们研究了左旋葡聚糖酮（LGO）在酸催化下异构化为5-羟甲基糠醛（HMF）的过程，并建立了一个反应动力学模型，该模型能够描述一系列条件（100 - 150 °C、50 - 100 mm H₂SO₄、50 - 150 mm LGO）下的实验数据。在这些反应条件下，LGO及其水合衍生物处于平衡状态。HMF的热降解和催化降解是碳损失的主要来源。在所研究的条件范围内，较高的温度和较短的反应时间有利于HMF的生成。当向水性溶剂体系中添加四氢呋喃时，HMF和乙酰丙酸的产率单调下降，这表明水在LGO异构化反应中起作用。初始速率分析表明，HMF仅由LGO生成，而非由LGO的水合衍生物生成。本研究结果与LGO异构化的一种机制一致，该机制通过脱水桥的水合作用，随后进行类似于葡萄糖异构化为果糖的环重排。
