Hydrothermal conversion of carbohydrate biomass to lactic acid

We investigated the hydrothermal conversion of the carbohydrates including glucose, cellulose, and starch to lactic acid using NaOH and Ca(OH)₂ as alkaline catalysts. Both catalysts significantly promoted the lactic acid formation. The highest yield of lactic acid from glucose was 27% with 2.5 M NaOH and 20% with 0.32 M Ca(OH)₂ at 300°C for 60 s. The lactic acid yields from cellulose and starch were comparable with the yield from glucose with 0.32 M Ca(OH)₂ at 300°C, but the reaction time in the case of cellulose was 90 s. The mechanism of lactic acid formation from glucose was discussed by identifying the intermediate products. Lactic acid may be formed via the formation of aldoses of two to four carbons including aldose of three carbons, which are all formed by reverse aldol condensation and double bond rule of hexose. This implies that carbon–carbon cleavage occurs at not only C₃? C₄ but also at C₂? C₃. © 2010 American Institute of Chemical Engineers AIChE J, 2010     

Production of bio‐crude from forestry waste by hydro‐liquefaction in sub‐/super‐critical methanol

Hydro‐liquefaction of a woody biomass (birch powder) in sub‐/super‐critical methanol without and with catalysts was investigated with an autoclave reactor at temperatures of 473–673 K and an initial pressure of hydrogen varying from 2.0 to 10.0 MPa. The liquid products were separated into water soluble oil and heavy oil (as bio‐crude) by extraction with water and acetone. Without catalyst, the yields of heavy oil and water soluble oil were in the ranges of 2.4–25.5 wt % and 1.2–17.0 wt %, respectively, depending strongly on reaction temperature, reaction time, and initial pressure of hydrogen. The optimum temperature for the production of heavy oil and water soluble oil was found to be at around 623 K, whereas a longer residence time and a lower initial H₂ pressure were found to be favorite conditions for the oil production. Addition of a basic catalyst, such as NaOH, K₂CO₃, and Rb₂CO₃, could significantly promote biomass conversion and increase yields of oily products in the treatments at temperatures less than 573 K. The yield of heavy oil attained about 30 wt % for the liquefaction operation in the presence of 5 wt % Rb₂CO₃ at 573 K and 2 MPa of H₂ for 60 min. The obtained heavy oil products consisted of a high concentration of phenol derivatives, esters, and benzene derivatives, and they also contained a higher concentration of carbon, a much lower concentration of oxygen, and a significantly increased heating value (>30 MJ/kg) when compared with the raw woody biomass. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

从生物量生产丙烯酸的研究和开发进展

1 INTRODUCTION Energy resources are divided into two categories: renewable and non-renewable. The fossil energy re- sources, such as petroleum, coal, natural gas and nu- clear energy, are non-renewable, whereas solar energy, hydraulic energy, wind power as well as biomass, etc., are renewable. Nowadays, worldwide efforts to reduce atmospheric CO2 emissions and to overcome the shortage and sharp price rise of fossil energy resources, especially petroleum, simultaneously trigger research on…     

生物质水热液化研究进展

水热液化技术可处理高含水率生物质且无需脱水等高耗能环节,具有良好的经济性与工业应用前景,已成为一种极具潜力的生物质能源利用方式。本文综述了生物质组分水热液化的机理,并对其应用生产进行了概述。回顾了生物质水热液化的研究历程,重点阐述纤维素、半纤维素、木质素、脂质和蛋白质等生物质的主要组分结构和水热液化反应机理,以及生物质水热液化反应器的工艺流程,明确了生物质水热液化存在的问题并对其发展方向进行展望。     

近临界水中乙酰丙酸的稳定性

乙酰丙酸有望成为一个基于生物质资源的新平台化合物,其制备过程中涉及高温高压水.实验测定了压力10 MPa、温度220～280 ℃内乙酰丙酸在近临界水中的稳定性.实验结果表明:近临界水中乙酰丙酸较稳定,在280 ℃、反应32 h下,乙酰丙酸的转化率仅为7.0%.乙酰丙酸降解反应为一级反应,分解反应的活化能为28.04 kJ/mol.     

Selective conversion of glucose into lactic acid and acetic acid with copper oxide under hydrothermal conditions

Biomass as a source for chemicals production attracts growing attention due to the decreasing storage of fossil fuels and global warming caused by emission of CO₂. In this study, conversion of glucose with copper oxide (CuO) was studied under alkaline hydrothermal conditions using a batch reactor and continuous flow reactor. CuO, as an oxidant, greatly improves the yields of lactic acid (LA) and acetic acid from glucose and was reduced into Cu₂O and Cu. Selective production of LA with the highest yield of 59% and acetic acid with the highest yield of 32% can be achieved by controlling reaction time, temperature, and addition of CuO. A possible mechanism of conversion of glucose with CuO was proposed. © 2012 American Institute of Chemical Engineers AIChE J, 59: 2096–2104, 2013     

模拟自然加快碳循环:水热转化生物质为高附加值产品

综述了作者所在科研组利用水热技术转化生物质成高附加值化工原料的一些最新进展。着重介绍了利用碳水化合物、木质纤维素、纤维素生物质以及生物柴油的副产物甘油产各种有机酸的研究进展,讨论了水热转化的机理和在水热转化中天然碳水化合物各组分之间的相互影响。最后介绍了中试规模连续水热反应系统利用植物源生物质生产乙酸的进展情况。     

焙烧活化后伊利石酸浸溶出铝钾动力学研究

采用酸浸水热工艺对吉林省安图县伊利石中铝和钾的溶出规律进行研究.考察了盐酸浓度、浸出时间、浸出温度及固液比因素对伊利石中铝和钾溶出率的影响.结果表明:试验实现了铝,钾的同步溶出;最佳试验条件下铝,钾溶出率分别为96.07%、93.89%.对溶出过程进行动力学研究表明,此条件下该溶出过程符合缩芯模型,低温状态下离子溶出过程受流体膜控制,高温状态下离子溶出过程受表面化学反应控制.     

生物质化学转化制备香料——乳酸的利用

化石资源的消耗以及其不断攀升的价格和二氧化碳排放带来的环境问题迫使人们开发可再生资源来生产能源和化学品等,即用生物质资源替代化石资源。乳酸是一种量大价廉的工业生物质原料,其本身和其经化学转化的产品均是香料制备的重要原料。以它们为原料已实现了双丁酯、呋喃酮、面包酮、γ-内酯、δ-内酯、偶姻、邻二酮和烷基吡嗪等重要香料的工业化生产。以丙烯酸酯为原料制备重要香料香豆素和二氢香豆素是一条绿色工艺,有望替代目前工业上采用的邻甲苯酚工艺。     

乳酸的生产技术及其研究进展

综述了绿色平台化合物——乳酸的生产方法及其最新技术研究进展,分析了乳酸生产技术发展的现状。认为关键问题是一方面要进一步完善现有的生产技术,另一方面应开发新的绿色合成技术,实现高效大规模生产,降低生产成本,并对绿色合成技术发展方向进行了分析和探讨。