2018 Fiscal Year Research-status Report
Synergy of Microwave and Graphene-Based Catalysis for Conversion of Sugars Into Useful Chemicals
| Project/Area Number |
18K05202
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| Research Institution | Kumamoto University |
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Principal Investigator |
キタイン アルマンド 熊本大学, グローバル教育カレッジ, 教授 (50504693)
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Keywords | microwave / carbocatalysis / graphene oxide / sugars / 5-HMF / subcritical water / functionalization / bifunctional catalysts |
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| Outline of Annual Research Achievements |
GO synthesized by Hummers’ method was successfully reduced using microwave irradiation. The reduced graphene oxide (rGO) was used as a catalyst.Water as a solvent, glucose and catalysts were placed in the reactor, and microwave irradiation was applied to heat the mixture to temperatures up to 240 oC at high temperature and reaction time of up to 60 min. The products were then analyzed by high performance liquid chromatography (HPLC). The highest yield of 5-HMF obtained at this condition was about 20%. By increasing the water-glucose ratio, two-fold increase in the yield up to 38.1% was observed, confirming the role of subcritical water as catalyst for the reaction.
Results had also confirmed rGO to be an efficient catalyst for the conversion of glucose, and synergism of carbocatalysis and microwave was found to be effective.
Future direction will include tailoring the catalyst having the optimum balance of acidity to further enhance glucose conversion to 5-HMF including doping it with phosphorus or boron. One student has been sent to Prof. Anke Krueger of Wuerzburg University (Germany) to study the methods of functionalization of P and B on carbon materials in order to increase Lewis acidity that will help in increasing the rate of isomerization of glucose to fructose. The next approach is to balance the Lewis and Bronsted acidities on the surface to increase the yield of 5-HMF above 50%.
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
In addition to the main topic going rather smoothly as planned, a new multilateral, multidisciplinary international research collaborative project on the application of the method (i. e. microwave carbocatalysis) for the conversion of algae into bioenergy has been approved for funding by the e-ASIA joint research program (JST funding of Japan side).This collaborative research project combined the expertise of top researchers in Southeast Asian region in solving the issues and challenges regarding the use of biomass for bioenergy and biochemical production in the region.
The method has also been applied to hydrolysis of marine polysaccharide (fucoidan) for fucose production.
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| Strategy for Future Research Activity |
The rGO-based catalysts will be tailored or functionalized based on the target compounds. A balance of Lewis and Bronsted acidities on the catalyst surface is important for the synthesis of 5-HMF. This can be adjusted by GO reduction by MW. This method detaches oxygen functionalities, thus increasing the Lewis acid sites on the GO surface. When necessary, GO will also be functionalized by nitrogen-doping with our simple, safe and novel approach using aqueous NH3.
A combination with Cu-based metal oxide catalysts to increase dehydration rate will also be explored. The catalysts will be characterized using XRD, FT-IR, SEM/TEM, XPS, TPD-NH3/CO2, etc.
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| Causes of Carryover |
An RI detector and a column oven were not purchased last fiscal year.The column oven was already available in the laboratory, and an ELSD detector will be purchased in the next fiscal year using other research funds. The allocated funds for these two equipments were diverted instead for consumables, thus incurring an excess amount to be used in the next fiscal year.
The incurred amount (40,176 yen) will be used next fiscal year for consumables since it is expected that more reagents and solvents will be used due to the promising results obtained in the previous year that will require further experimental investigation and verification.
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