Study On The Preparation Of 5-aminomethyl-2-furanmethanol Compounds By The Reductive Amination Of 5-hydroxymethylfurfural

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.