Structured Catalysts for Continuous Biphasic Furfural Synthesis from Biorefinery Feedstock.

Area of Science:

• Chemical Engineering
• Materials Science
• Biomass Conversion

Background:

• Sustainable chemicals are crucial for material transition, with lignocellulosic biomass offering a renewable source.
• Heterogeneous catalysts are preferred over homogeneous catalysts for xylose dehydration to furfural, a key platform chemical.
• Developing efficient and stable catalytic systems is essential for biomass valorization.

Purpose of the Study:

• To investigate the use of 3D open-cell aluminum foam structures coated with titanium dioxide (TiO2) as a support for heterogeneous catalysis.
• To evaluate the catalytic performance of TiO2-coated foams for biphasic furfural synthesis from biorefinery hydrolysate.
• To assess the long-term stability and mass transport properties of the developed catalytic system.

Main Methods:

• Fabrication of TiO2-coated 3D open-cell aluminum foams via dip-coating.
• Characterization of coating reproducibility and mechanical stability.
• Catalytic activity testing for xylose dehydration to furfural at temperatures ranging from 170-190 °C.
• Evaluation of mass transport limitations and long-term operation using sec-butylphenol as an organic extractant.

Main Results:

• TiO2-coated aluminum foams demonstrated high mechanical stability and reproducible coatings.
• Achieved approximately 60-70% furfural selectivity with near-complete xylose conversion at 170-190 °C.
• Enhanced mass transport properties of the foams minimized humin formation.
• Long-term operation exceeding 36 hours was achieved with sec-butylphenol as the extractant.
• Demonstrated absence of mass transfer limitations across varying foam thicknesses.
• Attained a furfural productivity of 5.8 × 10^-2 g_furfural g_cat^-1 min^-1, significantly higher than literature values.

Conclusions:

• 3D open-cell aluminum foams coated with TiO2 are effective supports for heterogeneous catalysis in furfural synthesis.
• The system exhibits excellent catalytic activity, selectivity, and long-term stability.
• This approach offers a promising pathway for efficient and sustainable production of furfural from lignocellulosic biomass.