Biomass, which is an important source of renewable energy offer advantages in terms of non-emission of greenhouse gases, ready availability and versatility in producing different organic materials. The conversion of biomass to biofuels such as furfural via xylose dehydration in the presence of an acidic catalyst has been extensively studied due to the multifarious capabilities of furfural. However, investigations need to be extended due to the fact that the conversion process may take a long time and sometimes, the acid catalysts used may face certain challenges due to high limits in reusability and unfavorable conversion process.
Researchers led by Professor Chanatip Samart from Thammasat University in Thailand studied the characteristics of a sulfonic-based functionalized MCM-41 catalyst SO3H-MCM-41 for the production of furfural from xylose monomers. The research work which is now published in the journal, Fuel carried on further investigations on its hydrophobic and porous nature towards performances on xylose dehydration.
Being known, that the level of acidity presence, in the catalyst directly affects the rate at which xylose is being converted, the authors added acidic sites on the SO3-MCM-41 catalyst, with the first obtained as propyl sulfonic acid catalyst PrSO3H-MCM-41 and the second, methyl propyl sulfonic acid catalyst MPrSO3H-MCM-41. The functional methyl group of MPrSO3H-MCM-41 catalyst was investigated in order to verify its influence on performance, while its pore size diameter was controlled by using cetyltrimethyl ammonium bromide (CTAB) as a templating agent and another, by increasing the temperature to 500C.
With the use of ammonia-temperature programmed desorption analyses, the authors found a higher presence of acid density in MPrSO3-MCM-41 catalyst compared to that of PrSO3H-MCM-41. However, a lower density was observed in the former.
The methyl propyl sulfonic acid catalyst at a certain increase in reaction temperature (140, 155 and 170°C) and reaction time led to an increase in the rate of xylose dehydration. However, the optimum yield and selectivity of furfural was observed in reaction time and temperature of 2h and 155°C with values of 68.6 and 71.9% respectively. The MPrSO3H-MCM-41 catalyst also had a higher rate of xylose dehydration and turn over frequency TOF compared to PrSO3H-MCM-41 catalyst as the turn over frequency increased from 5.47h-1 to 8.15h-1. This result indicates that the higher acid density of MPrSO3H-MCM-41 catalyst resulted to a higher turnover frequency values.
They also showed that reduced pore diameter of the MPrSO3H-MCM-41 catalyst led to a higher yield and selectivity of furfural with values greater than 90 and 93% respectively. Moreover, continual use of the MPrSO3H-MCM-41 catalyst for a period of three cycles at the optimal reaction process still showed a better xylose dehydration but the furfural yield and selectivity decreased drastically.
The authors in this study were able to develop an alkyl sulfonic-based catalyst which has a high efficiency in xylose dehydration and selectivity of furfural.
S. Kaiprommarat1, S. Kongparakul1, P. Reubroycharoen2, G. Guan3, C. Samart1, Highly efficient sulfonic MCM-41 catalyst for furfural production: Furan-based biofuel agent, Fuel 174 (2016) 189–196.Show Affiliations
- Department of Chemistry, Faculty of Science and Technology, Thammasat University, Pathumthani 12120, Thailand
- Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
- North Japan Research Institute of Sustainable Energy (NJRISE), Hirosaki University, Aomori 030-0813, Japan
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