Effective conversion sucrose into 5-hydroxymethylfurfural by tyrosine in [Emim]Br

• Glycosidic bond hydrolysis couples with fructose dehydration to promote reaction.
• 1,2-Glycosidic bond was more difficult cleavage than 1,4-glycosidic bond.
• Amino group plays a great role in the rate-determining step of glucose isomerization.
• COOH well catalyzes sucrose hydrolysis and fructose dehydration.
• Tyrosine displays the best activity in sucrose conversion to 5-HMF.

In this study, the synthesis of 5-hydroxymethylfurfural (5-HMF) from sucrose was carried out in ionic liquids 1-ethyl-3-methylimidazolium bromide ([Emim]Br) catalyzed by amino acids, and tyrosine displays the best activity. Under the optimal reaction conditions, 76.0% yield of 5-HMF from sucrose was obtained at 160 °C for 4 h. The uniquely effective activity of tyrosine for sucrose conversion into 5-HMF in [Emim]Br is mainly attributed to its two types of active sites, free base NH2 and dissociated H+ sites. The former one plays a crucial role in the isomerization of glucose to fructose, and the latter one is active in the hydrolysis of sucrose into monosaccharides and dehydration of generated fructose to 5-HMF. Furthermore, the presence of acidic phenol group in tyrosine also has the synergic catalytic effect on sucrose conversion. In addition, with the use of tyrosine catalyst, other carbohydrates to form 5-HMF were also tested, and the effects of solvent, reaction temperature and reaction time on sucrose conversion into 5-HMF were investigated in detail. A possible mechanism for this catalytic process has been proposed.

Figure optionsDownload high-quality image (207 K)Download as PowerPoint slide