Possible adducts formed between hydroxymethylfurfural and selected amino acids,and their release in simulated gastric model

This work aimed to investigate the reactivity of hydroxymethylfurfural (HMF) with selected amino acids, to identify the produced adducts and to clarify whether or not the adducts release HMF after their digestion under gastric conditions. Results showed that cysteine, glycine and lysine can deplete the added HMF, and their reactivity increased with increasing pH and temperature. Cysteine (25 μmol mL^?1) depleted 91.0% of the added HMF (315.3 μg mL^?1) at 40 °C in 15 min, lysine did not eliminate HMF until 80 °C, and glycine started to eliminate HMF at 100 °C. Four adducts for cysteine, three adducts for lysine and only one adduct for glycine were identified through HPLC–MS–MS after they reacted with HMF. The adducts formed from the reaction mixture of cysteine, lysine and glycine with HMF only released 1.7%, 2.6% and 10.5% of eliminated HMF, respectively, after their digestion in simulated gastric conditions.     

Hydrodeoxygenation of HMF over Pt/C in a continuous flow reactor

The three‐phase hydrodeoxygenation reaction of 5‐hydroxymethylfurfural (HMF) with H₂ was studied over a 10 wt % Pt/C catalyst using both batch and flow reactors, with ethanol, 1‐propanol, and toluene solvents. The reaction is shown to be sequential, with HMF reacting first to furfuryl ethers and other partially hydrogenated products. These intermediate products then form dimethyl furan (DMF), which in turn reacts further to undesired products. Furfuryl ethers were found to react to DMF much faster than HMF, explaining the higher reactivity of HMF when alcohol solvents were used. With the optimal residence time, it was possible to achieve yields approaching 70% in the flow reactor with the Pt/C catalyst. Much higher selectivities and yields were obtained in the flow reactor than in the batch reactor because side products are formed sequentially, rather than in parallel, demonstrating the importance of choosing the correct type of reactor in catalyst screening. © 2014 American Institute of Chemical Engineers AIChE J, 61: 590–597, 2015     

Conversion of carbohydrates into 5‐hydroxymethylfurfural in a green reaction system of CO2‐water‐isopropanol

In this work, a green reaction system of CO₂‐water‐isopropanol was developed for 5‐hydroxymethylfurfural (HMF) production. The conversion of fructose in a CO₂‐water system was first investigated, and the results showed this system could promote the formation of HMF compared to a pure water system. Then, isopropanol was introduced into the CO₂‐water system and the HMF formation became better because the solvent effect of isopropanol increased the tautomeric composition of fructofuranose, which was easy to form HMF. The existence of isopropanol was found to greatly suppress secondary reactions where HMF was converted to levulinic acid and insoluble humin. Meanwhile, the effects of reaction parameters on the conversion of fructose to HMF in the CO₂‐water‐isopropanol system were analyzed, and a high HMF yield of 67.14% was obtained. Finally, to further illustrate the merits of CO₂‐water‐isopropanol system, productions of HMF from other carbohydrates were tested and satisfactory yields were achieved. © 2016 American Institute of Chemical Engineers AIChE J, 63: 257–265, 2017     

纤维素选择性催化转化为重要平台化合物的研究进展

纤维素是自然界中最丰富的植物生物质组分,拓宽纤维素的利用对于减少化石资源使用和可持续发展非常重要。本文综述了以纤维素为原料,通过化学催化转化得到平台化合物葡萄糖、羟甲基糠醛、乙酰丙酸、多元醇的方法,包括离子液体催化、固体酸催化和贵金属催化加氢等,以及上述平台化合物后续转化的途径。如羟甲基糠醛的氧化与还原,乙酰丙酸制备γ-戊内酯、烃、1,4-戊二醇和甲基四氢呋喃,以及多元醇催化重整制备液体燃料。提出纤维素催化制备平台化合物的研究成果将为可再生资源替代化石资源的可持续发展提供有力的理论支持和实践指导。     

Furosine is a useful indicator in pre‐baked breads

There is increasing demand for pre‐baked bread. Bakers can meet consumer requirements for breads of specific flavour and colour by pre‐baking an amount of bread in the morning and completing the baking process in the afternoon. This type of product is of special interest to sandwich bars, restaurants and large communities. In order to obtain an indicator of utility to monitor the processing of pre‐baked bread, the browning indicators furosine, hydroxymethylfurfural (HMF) and glucosylisomaltol were analysed in two independent assays of bread pre‐baked at 175 °C for between 5 and 30 min. No furosine was detected in raw or fermented dough. In the pre‐baking stage, furosine increased from 1.5‐ to 5‐fold between 5 and 30 min. The furosine values obtained in the two independent experiments were similar. HMF and glucosylisomaltol were only detected after 15 min, which is the time period commonly used for processing by the industry. Thus, among these indicators, furosine is the only one with utility for monitoring the pre‐baking process. On the other hand, a study of the baking of pre‐baked bread at 220 °C showed that HMF and glucosylisomaltol can be used to monitor the latter process. Copyright © 2004 Society of Chemical Industry     

原位合成碘催化蔗糖制备5-羟甲基糠醛

着重研究以原位合成碘(即三氯化铬和碘化钠发生氧化还原反应产生的碘)为催化剂,蔗糖为原料制备羟甲基糠醛.考察了反应时间、反应温度、催化剂用量(以三氯化铬和碘化钠质量计)、蔗糖质量百分数对羟甲基糠醛收率的影响.得到以原位合成碘为催化剂的优化条件:时间45min、温度130℃、催化剂用量0.25g、蔗糖质量百分数8%.在此优...     

Hydroxymethylfurfural Accumulation in Applesauce Packaged in Multilayer Polymer Films and Glass

Applesauce packaged in four different multilayer polymer films and glass was evaluated for changes in hydroxymethylfurfural content during storage. Packages were held for 15 wk at 20°, 30°, 37° and 43°C. Hydroxymethyfurfural content was measured by HPLC analysis every 5 weeks. For all package types more HMF was measured at higher storage temperatures as expected, however, total amounts of HMF also varied according to package type. Comparison of HMF across . package types as an index of thermal history would be of questionable value.     

石墨烯负载钯纳米颗粒催化5-羟甲基糠醛选择氧化制2,5-呋喃二甲酸

采用甲醛液相还原法制备石墨烯负载Pd纳米颗粒催化剂,利用HRTEM、STEM、HAADF、XPS、TG、XRD、N2物理吸附、CO脉冲化学吸附等手段对样品进行表征。结果显示,高比表面积石墨烯作为催化剂载体,有助于获得高分散和金属态为主的Pd纳米颗粒。HMF催化氧化实验表明,Pd/rGO催化剂能够高效催化HMF转化为FDCA。50℃常压反应6h,HMF转化率和FDCA的收率分别为96.9%和66.6%。反应动力学结果显示,HMF转化和生成FDCA的活化能分别为(45.6±4.6)kJ/mol、(71.3±2.5)kJ/mol。