基于微波湿烘焙畜粪生物质提质研究

采用微波湿烘焙方法,对马粪进行烘焙预处理,考察了反应溶剂和烘焙温度对马粪组成、热降解特性、高位热值、能量产率及形貌特性的影响。结果表明,马粪的固定碳含量和高位热值随温度升高而增长,能量产率随温度升高而降低。与原料相比,在200℃时,水溶剂中所得烘焙马粪的固定碳含量大幅增长,O/C比减小28.00%,高位热值增长21.07%,能量产率保留74.30%。与原料相比,水和琥珀酸溶剂中所得烘焙马粪仍存在较多的灰分含量,硫酸溶剂能减少形成灰分的金属元素含量,使马粪灰分含量减少50.00%。微波湿烘焙降低了马粪的热解反应性,并提高其燃烧反应性。水溶剂中所得烘焙马粪,其表面的孔隙结构更清晰。研究显示,微波湿法烘焙可对马粪提质,200℃是本实验的最佳反应温度,恒温200℃时,水比稀酸更适合作为反应溶剂。     

杂多酸及其盐催化D-果糖选择性合成5-羟甲基糠醛

考察了杂多酸及其盐对果糖脱水制备HMF的催化性能。研究表明,磷钨酸铯盐催化效果较好,高温反应对5-羟甲基糠醛(HMF)生成有利,添加助剂聚乙烯吡咯烷酮(PVP)可提高产率。通过对反应温度、催化剂、加料方式的考察,得出优化的反应条件为:将果糖溶于DMSO中,添加质量分数20%的PVP,升温至155℃加入占果糖摩尔分数1%的CsH2PW12O40,反应5 min,产率77.9%。     

固体酸催化菊糖制备5-羟甲基糠醛(HMF)的研究

研究了二甲基亚砜(DMSO)作溶剂,TiO2-SiO2为催化剂时菊糖脱水生成5-羟甲基糠醛(HMF)的反应。考察了不同钛硅比的TiO2-SiO2催化剂和反应时间对制备HMF收率的影响。实验结果表明,反应温度为150℃,钛硅比为5∶5,反应时间为3 h,HMF的收率可达54.6%。     

生物质双相溶剂体系制备5-羟甲基糠醛的过程强化研究进展

5-羟甲基糠醛（HMF）作为一种基于木质纤维素类生物质的重要平台化合物,是多类高价值化学品和液体燃料的前体,但因理化性质不稳定,其高效制备面临巨大挑战。单一溶剂体系中生物质降解所得HMF产率低且副产物多,在原反应相中加入有机溶剂实现反应过程中HMF的原位萃取可大幅提高其选择性,目前采用双相溶剂体系已成为研究主流。本文在介绍双相溶剂体系、有机溶剂、反应原料、催化剂等影响生物质液相降解制备HMF的基础上,揭示优化反应条件强化两相溶剂界面传质对提高产物产率和反应效率的重要作用,并围绕增强相界面扰动和优化溶剂体系两个主要方面,重点综述了基于传质强化的生物质两相溶剂体系降解制备HMF的研究现状,最后对未来发展趋势进行了展望。     

酸水解法分离玉米芯中五碳糖和六碳糖的动力学

以玉米芯为底物,采用间歇反应釜,在固液比为0.1 g/mL,一定硫酸浓度(质量分数为0.1%~0.9%)和温度(130~170℃)下反应,建立酸水解动力学模型,通过非线性回归拟合获得模型参数。结果表明:较低温度和硫酸浓度可增大五糖碳收率和玉米芯中六碳糖保留率。合适的反应条件为130℃,H2SO4的质量分数为0.1%,反应82 min时,溶液中五碳糖浓度为36.2 g/L,五糖碳收率为90.7%,玉米芯中戊聚糖水解率为97.6%,六碳糖保留率为96.9%。     

不同己糖二酸脱水环合制备2,5-呋喃二甲酸的对比研究

己糖二酸脱水环合制备2,5-呋喃二甲酸(2,5-FDCA)是一条具有工业化应用前景的路线。己糖二酸包括葡萄糖二酸、半乳糖二酸和甘露糖二酸,三者是同分异构体,空间结构有差别。本文研究了己糖二酸原料对脱水环合制备2,5-FDCA动力学的影响。结果表明,不同己糖二酸原料对脱水环合制备2,5-FDCA收率影响较大,收率从大到小的次序为:葡萄糖二酸-1,4-内酯葡萄糖二酸钙葡萄糖二酸单钾盐半乳糖二酸。与半乳糖二酸相比,以葡萄糖二酸钙为原料制备2,5-FDCA不仅收率高,而且反应条件温和。拟合得到葡萄糖二酸钙的降解反应活化能、2,5-FDCA生成活化能和其他副反应活化能分别为91.7、87.7和98.2 kJ×mol~(-1),而半乳糖二酸的降解反应活化能、2,5-FDCA生成活化能和其他副反应活化能分别为95.2、92.2和98.3 kJ×mol~(-1),可见葡萄糖二酸钙的降解反应活化能和2,5-FDCA生成活化能均比半乳糖二酸的低,主、副反应的活化能之差大于半乳糖二酸的,在硫酸催化下葡萄糖二酸钙更易生成2,5-FDCA。本研究工作将为己糖二酸路线制备2,5-FDCA提供重要的基础数据。     

提高葡萄糖差向异构转化生成甘露糖收率的研究

本文利用单因素实验和正交试验,深入研究并确定提高葡萄糖异构反应转化生成甘露糖收率的反应条件。通过正交试验并结合实际情况,得出的实际优化条件为:钼酸铵用量为葡萄糖量的0.4%、反应温度98℃、反应时间150min、反应液pH值0.2、糖液浓度55%,所得到的甘露糖收率可达到32.6%。     

半乳糖二酸催化脱水环合制备2,5-呋喃二甲酸工艺及动力学

2,5-呋喃二甲酸（2,5-FDCA）是生物质基的平台化合物之一，在聚合物领域有广泛的应用前景。针对半乳糖二酸脱水环合制备2,5-FDCA存在的收率低、动力学数据缺乏等问题，在催化剂和溶剂筛选的基础上，开展了半乳糖二酸制备2,5-FDCA的工艺优化，得到了较佳的工艺条件为15%(质量)硫酸催化、环丁砜为溶剂、130℃下反应16 h，此时2,5-FDCA收率为49.1%。测定了不同硫酸浓度和不同温度下半乳糖二酸脱水环合制备2,5-FDCA反应动力学数据，采用一级反应动力学拟合得到了15%(质量)硫酸催化下半乳糖二酸降解反应活化能为54.4 kJ/mol、2,5-FDCA生成活化能为57.8 kJ/mol、其他副反应的活化能为50.7 kJ/mol、2,5-FDCA进一步降解反应的活化能为130.6 kJ/mol。研究工作对己糖二酸路线制备2,5-FDCA工业化进程有一定的推动作用。     

环境友好催化剂催化葡萄糖水解的研究

研究了n(SiO₂)∶n(Al₂O₃)=20～25的ZRP-5分子筛（催化剂1）、n(SiO₂)∶n(Al₂O₃)=30的ZRP- 5分子筛（催化剂2）、甲酸、液态水四种催化剂分别催化葡萄糖水解。研究发现，葡萄糖水解机理复杂,产物众多，水解主产物为乙酰丙酸(LA)，同时还有5 羟甲基糠醛(HMF)、果糖、乳酸、甲酸、呋喃甲醛等副产物生成。不同的催化剂对葡萄糖的转化率影响不大，但各个反应产物收率相差很大。HMF的生成比较容易，而LA的生成相对困难。ZRP-5分子筛催化剂对LA具有良好的选择性。     

木质纤维素制备5-羟甲基糠醛的催化过程强化

5-羟甲基糠醛(HMF)是一种链接可再生生物质资源与燃料化合物及化学中间体的重要新型平台化合物。文中对高温(180—200℃)条件下,金属氯化物为催化剂,离子液体[BMIM]Cl为溶剂,木质纤维素(相思木木屑)为原料快速制备HMF和糠醛的反应过程进行了研究。通过对反应温度、原料用量、盐酸(HCl)添加量、催化剂种类及用量等因素进行考察,优化了反应条件。研究结果表明:与文献报道的低温下纤维素降解反应相比,高温条件可使木质纤维素为原料制备HMF的反应过程得到强化。在所考察的金属氯化物催化剂中,CrCl3.6H2O的催化效果最优,其中以CrCl3.6H2O为催化剂,200℃下反应4 min时产物HMF及糠醛的收率分别可达55.0%和22.9%。该高温反应过程反应快速、产物收率高,无需木质纤维素原料的预处理操作,为工业上简单快速制备HMF提供了一种可行方法。     

Hydrochloric acid‐catalyzed levulinic acid formation from cellulose: data and kinetic model to maximize yields

In this study, the kinetics of the acid catalyzed hydrolysis of microcrystalline cellulose (Avicel PH101) to levulinic (LA) and formic (FA) acids was investigated in a batch reactor over the following range of conditions: 160–200°C, hydrochloric acid concentrations of 0.309–0.927 M (11.3–33.8 g/l), cellulose concentrations of 49.8–149 mM (8.06–24.1 g/l), and residence times of 0–50 min. The maximum LA yield of around 60% of theoretical was achieved for an initial cellulose concentration of 99.6 mM, acid concentration 0.927 M, and 180–200°C. A mathematical model and its analytical solution were developed to predict conversion of cellulose to LA and FA through glucose and hydroxymethyl‐2‐furfural based on an irreversible pseudo‐first order reaction. Rate analysis of each reaction indicated that the rate‐controlling step shifted from LA formation initially to HMF formation later. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

Valorization of galactose into levulinic acid via acid catalysis

We applied methanesulfonic acid (MSA) as a green catalyst to produce levulinic acid (LA) from monomeric sugars. To optimize reaction factors and assess the effect of reciprocal interactions, a statistical experimental design was applied. Optimized result of 40.7% LA yield was obtained under the following conditions: 60 g/L galactose, 0.4M MSA at 188 °C for 26.7 min. On the other hand, 66.1% LA yield was achieved under 60 g/L fructose and 0.4M MSA at 188 °C for 36 min conditions. For the effect of combined severity factor on the LA yield from galactose, the LA yield showed a peaked pattern, which was linearly increased until a CSF 3.2 and then diminished with a high CSF. Moreover, it was closely fitted to a non-linear Gaussian peak pattern with a high regression value of 0.989. These results suggest that MSA and galactose, derived from marine red macro-algae, can potentially be applied for the conversion into platform chemicals.     

The preparation of 5-hydroxymethylfurfuraldehyde from high fructose corn syrup and other carbohydrates

5-Hydroxymethylfurfuraldehyde (HMF) was prepared from high fructose corn syrup (HFCS), or crystalline D -fructose, in high yield and purity. A 95–97% conversion of fructose to HMF was achieved using 25 mol% (based on fructose) boron trifluoride etherate catalyst in dimethyl sulphoxide, under a nitrogen atmosphere, a reaction temperature of 273 K and 30 min reaction time. Inferior yields of HMF were obtained from glucose and starch.     

Catalytic production of hydroxymethylfurfural from sucrose using 1-methyl-3-octylimidazolium chloride ionic liquid

Hydroxymethylfurfural (HMF) is an important chemical intermediate, but it has not been widely used because of low yields and high production costs. Sucrose is available at lower costs than other sugars and thus could be a biomass-derived abundant source for HMF production. In this study, a catalytic process for efficiently producing HMF from sucrose was scrutinized using 1-methyl-3-octylimidazolium chloride ([MOIM]Cl) as a reaction solvent, and HCl and metal chlorides (CrCl₂ and Zncl₂) as a catalyst. The rate of sucrose hydrolysis was relatively much faster in the reactions with HCl than without it. The hydrolysis of sucrose to fructose and glucose was affected by its reaction time. The mixed solvent of 50% [MOIM]Cl and 50% sucrose solution with HCl was more effective in HMF synthesis than single solvent alone. The addition of ZnCl₂ and CrCl₂ increased HMF yields by approximately 1.2–1.8-fold and its higher yield was found in the latter. The highest yield (82.0±3.9 wt%) in HMF production was achieved in the reaction mixture containing 5 g [MOIM]Cl and 5 mL of 20% sucrose solution with 0.5M HCl plus CrCl₂ at 30 min reaction time. However, 0.3 M HCl was more effective for the HMF productivity than 0.5 M HCl.     

固体酸催化果糖制备5-羟甲基糠醛的研究

研究了以二甲基亚砜为溶剂、TiO_2-SiO_2为催化剂催化果糖脱水生成5-羟甲基糠醛(HMP)的反应,分别考察了不同摩尔比TiO_2-SiO_2催化剂、反应时间、催化剂用量、果糖添加量等工艺参数对果糖脱水制备HMF催化活性的影响.在TiO_2-SiO_2作为催化剂、150℃和反应3 h的条件下,5-羟甲基糠醛的收率可达83.8%.     

Absence of expected side-reactions in the dehydration reaction of fructose to HMF in water over niobic acid catalyst

The catalytic dehydration of fructose (FRU) to 5-hydroxymethylfurfural (HMF) usually runs with the formation of several side products. Among these, levulinic acid (LA) is often reported as the product of a consecutive reaction of HMF re-hydration. In this work, side reactions of the dehydration of FRU performed in very green conditions (water as solvent and niobic acid as solid catalyst) are taken into account. Experimental evidences are given that, in the used conditions: i) HMF is a final stable product, ii) no formation of LA, either deriving from a consecutive reaction of HMF or directly from FRU transformation, was observed, and iii) LA does not react to give condensation products with any other chemical species present in the reaction mixture.     

SnO2/Fe2O3-rGO三元复合材料催化葡萄糖脱水制备5-羟甲基糠醛

采用水热晶化法制备SnO2/Fe2O3-rGO三元复合材料固体型催化剂,以葡萄糖为原料,SnO2/Fe2O3-rGO为催化剂,在[BMIM]Br环境下催化葡萄糖脱水制备5-羟基甲糠醛(HMF)。考察催化剂制备条件及催化制备5-羟甲基糠醛(HMF)的工艺参数如:催化剂制备的晶化温度、不同金属原料配比、以及不同溶剂对(HMF)产率的影响等。实验结果表明,在200℃下,n(FeCl3·6H2O)∶n(SnCl2·2H2O)=1∶3,恒温4 h,制备的催化剂SnO2/Fe2O3-rGO在[BMIM]Br离子液体中对葡萄糖脱水制备HMF所得葡萄糖转化率为99%,产率为56%。     

2,2′,6,6′-四甲氧基-4,4′-二(二苯基氧膦)-3,3′-联吡啶的合成

以2,6 二氯吡啶为起始原料,首先合成了2,6 二甲氧基吡啶,而后经过-20～-40℃下吡啶环的溴化反应,合成了中间产物2,6 二甲氧基 3 溴吡啶,收率为74 8%;进而,在-78℃条件下利用Ph2PCl作为亲电试剂进行亲电取代反应制备了中间产物2,6 二甲氧基 3 溴 4 二苯基膦吡啶,收率为77 4%;最后,利用0℃下三价膦的氧化反应合成了2,6 二甲氧基 3 溴 4 二苯基氧膦吡啶及150℃下吡啶环的偶合反应,合成出了目标产物2,2′,6,6′ 四甲氧基 4,4′ 二(二苯基氧膦) 3,3′ 联吡啶,收率分别为95 3%和62 5%,整个合成过程的总收率为27 8%。在合成过程中采用氢谱、碳谱等核磁共振方法鉴定了一些重要中间产物和目标产物的分子结构。