Title : Integrated two stage processing of biomass conversion to HMF esters using ionic liquid as green solvent and catalyst: Synthesis of mono esters
Abstract:
In this study a two stage process were established for the synthesis of HMF esters using ionic liquid acid catalyst. Ionic liquid catalyst with different strength of the Bronsted acidity was synthesized in laboratory and characterized using 1 H NMR, FT-IR and 13C NMR spectroscopy. Solid acid catalyst from the ionic liquid catalyst was prepared using immobilization method. The acidity of the synthesized acid catalyst was measured using Hammett function and titration method. Catalytic performance was evaluated for the biomass conversion to 5-hydroxymethylfurfural (5-HMF) and levulinic acid (LA) in methyl isobutyl ketone (MIBK)-water biphasic system. Good yield of 5-HMF and LA was found at the different composition of MIBK: Water. In case of MIBK: Water ratio 10:1, good yield of 5-HMF and LA was observed at ambient temperature 150 ?C. Upgrading of 5-HMF into mono esters from the reaction of 5-HMF and reactants using biomass derived mono acid were performed. Ionic liquid catalyst with -SO3 H functional group was found to be best efficient in comparative of solid acid catalyst for the esterification reaction and biomass conversion. A good yield of 5-HMF esters with high 5-HMF conversion was found to be at 105 ?C using the best active catalyst. In this process, process A was the hydrothermal conversion of biomass and its monomer into 5-HMF and LA using acid catalyst. And the process B was the esterification followed by using similar acid catalyst. All mono esters of 5-HMF synthesized here can be used in chemical, cross linker for adhesive or coatings and pharmaceutical industry. A theoretical density functional theory (DFT) study for the optimization of the ionic liquid structure were performed using Gaussian 09 program to find out the minimum energy configuration of ionic liquid catalyst and their comparative Bronsted acidic strength.
Audience Take Away:
- Ionic liquid synthesis and their acidity characterization using Hammett acidity function.
- Immobilization of the ionic liquid on to the solid support for the synthesis of solid acid catalyst.
- Finding the minimum energy configuration using density functional theory (DFT) probably that structure is responsible for catalytic activity.
- Using DFT calculation we can find out the reaction pathway for the esterification reaction of 5-HMF with different acids.
