【作者】 陈伟；

【导师】 林鹿；

【作者基本信息】 厦门大学 ， 材料工程， 2017， 硕士

【摘要】 生物质是唯一可以替代化石资源为人类提供燃料、材料和化学品的可再生资源,生物质经平台分子转化为高附加值的化学品是生物质资源利用的重要途径之一。5-轻甲基糠醛(5-Hydroxymethylfurfural,HMF)是一种重要的生物质基平台化合物,通过HMF的还原胺化可以将生物质转化为5-氨甲基-2-呋喃甲醇类化合物。本论文以转化平台分子实现生物质的高值化利用为目标,围绕HMF还原胺化制备 5-[(二甲氨基)甲基]-2-呋喃甲醇(5-[(Dimethylamino)methyl]-2-furanylmethanol,DMMF)和 5-氨甲基-2-呋喃甲醇(5-Aminomethyl-2-furanmethanol,AMF)开展了一系列研究,并取得一定的研究成果。首先,研究了以甲酸作为还原剂,在无金属催化剂的条件下HMF与N,N-二甲氨基甲酰胺(N,N-Dimethylformamide,DMF)直接还原胺化制备DMMF。在HMF、DMF、甲酸、去离子水用量分别为3wt%、5wt%、24.5wt%和57.4wt%的条件下,常压回流反应6h,HMF的转化率和DMMF的收率分别达到100%和76.2%;探究了甲酸用量及体系pH等反应条件对HMF还原胺化反应的影响;采用硅胶柱层析法分离纯化反应液中的主要产物,利用13C NMR和1H NMR分析确定各产物的分子结构,并根据主要产物提出了 HMF还原胺化的转化路径;在此基础上,进一步研究使用碳水化合物一锅法制备DMMF,在碳水化合物、DMF、甲酸、去离子水加入量分别为5wt%、15wt%、48wt%、32wt%,120℃下反应6h的条件下,葡萄糖、果糖和蔗糖转化为DMMF的收率分别达到26.2%、39.5%和33.5%;研究了葡萄与果糖转化路径的差异,并提出了由葡萄糖制备DMMF可能的转化机理。其次,研究了以氨水和氢气分别作为氨供体和还原剂,以雷尼镍(Raney-Ni)催化HMF在甲醇/水体系中直接还原胺化制备AMF。在HMF用量为0.64g,氨用量为14.5当量,氢气压力为12 bar,100 ℃反应4 h的条件下,AMF的收率达90.6%;研究发现反应体系中水的存在可以促进AMF水解形成铵盐,并抑制了 AMF的进一步反应,进而对AMF有一定的稳定作用。最后,研究了以氨水和氢气分别作为氨供体和还原剂,Ni/SBA-15催化HMF在甲醇/水体系中催化HMF还原胺化制备AMF。相对于Raney-Ni,在类似的反应条件下,达到相近的催化效果,催化剂的用量由Raney-Ni的7.8 wt%减少到Ni/SBA-15的2.34wt%;与Pd/C、Pt/C、Ru/C贵金属催化剂相比,Ni基催化剂的催化活性适中,对末端C=N还原的催化选择性较高,在催化HMF还原胺化反应中具有更好的催化效果;此外,循环实验发现Ni/SBA-15有较好的循环性能,重复使用5次后,依然保持较好的催化活性。更多还原

【Abstract】 Biomass is considered to be the only renewable resources in nature to replace the fossil resources for producing fuels,chemicals and materials.The conversion of biomass into value-added chemicals via platform molecule is one of the most important pathway for the utilization of biomass.5-Hydroxymethylfurfural(HMF)is one of the most important biomass-derived platform molecules,and the biomass can be converted to 5-aminomethyl-2-furanylmethanol compounds via reductive amination of HMF,A series of studies were carried out in this dissertation with the aim of high value utilization of biomass by the transformation of platform molecule HMF.Specifically,a series of studies were performed to convert biomass into 5-[(dimethylamino)methyl]-2-furanylmethanol(DMMF)and 5-aminomethyl-2-furanmethanol(AMF)by the reductive amination of HMF.Firstly,an efficient process for the preparation of pharmaceutical intermediate DMMF by direct reductive amination of HMF with N,N-dimethylformamide(DMF)was presented using formic acid as reducing agent without of catalyst.HMF conversion of 100%and DMMF yield of 76.2%were obtained under the following conditions:3 wt%HMF,5 wt%DMF,24.5 wt%formic acid and 57.4 wt%water,reflux reaction for 3 h.The effects of the amount of formic acid and the pH of the system on the reductive amination of HMF were investigated.The main products were separated and purified by silica gel column chromatography,and its chemical structure were determined by 13C NMR and 1H NMR analysis.The conversion pathway of the reductive amination of HMF was proposed according to the main products.Further more,a process for the preparation of DMMF by the one-pot conversion of carbohydrates was presented,and DMMF yields of 26.2%,39.5%and 33.5%were obtained from glucose,fructose and sucrose,under the following reaction conditions:5 wt%carbohydrates,15 wt%DMF,48 wt%formic acid and 32 wt%water,120 ℃,6 h,respectively.Aplausible mechanism for the dehydrationand reductive amination of glucose into DMMF was also proposed.Secondly,an efficient process for the preparation of AMF by the direct reductive amination of HMF with aqueous ammonia over Raney-Ni was presented.The optimal AMF yield of 90.6%was obtained under 12 bar H2 at 100 ℃ in 4 h with 14.5 equivalents ammonia relative to HMF.It was found that the presence of water in the reaction system would stabilize AMF through promoting hydrolysis of AMF to form alkylammonium ion,which restrains further reaction with HMF.Finally,Ni/SBA-15 was used to catalyzze the direct reductive amination of HMF to AMF with aqueous ammonia.Compared to Raney-Ni,catalyst addition was reduced to 2.34 wt%from 7.8 wt%for the similar catalytic effect.Nickel based catalysts displayed higher catalytic selectivity in HMF reductive amination compared with other precious metal catalysts,such as Ru/C,Pd/C,Pt/C.This feature of nickel catalysts was mainly attributed to their proper catalytic activity for the hydrogenation of terminal C=N group,giving high selectivity towards AMF.Moreover,recycling experiments demonstrated an acceptable recyclability of Ni/SBA-15 catalyst,no significant loss of catalytic activity of Ni/SBA-15 was observed after five consecutive use.更多还原