Ethanol dehydrogenation to acetaldehyde over activated carbons-derived from coffee residue

DOI: https://doi.org/10.9767/bcrec.0.0.3335.xxx-xxx
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Article Info
Submitted: 02-10-2018
Published: 25-01-2019
Section: Original Research Articles
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This study focuses on the production of acetaldehyde from ethanol by catalytic dehydrogenation using activated carbon catalysts derived from coffee ground residues and commercial activated carbon catalyst. For the synthesis of activated carbon catalysts, coffee ground residues were chemical activated with ZnCl2 (ratio 1:3) followed by different physical activation. All prepared catalysts were characterized with various techniques such as nitrogen physisorption (BET & BJH methods), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX), CO2-TPD, NH3-TPD, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectrometer (FT-IR) and thermogravimetric analysis (TGA). The dehydrogenation of vaporized ethanol was performed to test the catalytic activity and product distribution. Testing catalytic activity by operated in a fixed-bed continuous flow micro-reactor at temperatures ranged from 250 to 400°C. It was found that the AC-D catalyst (using calcination under carbon dioxide flow at 600oC, 4 hours for physical activation) exhibited the highest catalytic activity, while all catalysts show high selectivity to acetaldehyde (more than 90%). Ethanol conversion apparently increased with increased reaction temperature. At 400oC, the AC-D catalyst gave the highest ethanol conversion of 47.9% and yielded 46.8% of acetaldehyde. The highest activity obtained from AC-D catalyst can be related to both Lewis acidity and Lewis basicity because the dehydrogenation of ethanol uses both Lewis acid and Lewis basic sites for this reaction. To investigate the stability of catalyst, the AC-D catalyst showed quite constant ethanol conversion for 10 h. So, the synthesized activated carbon from coffee ground residues is promising to be used in dehydrogenation of ethanol.

Received: 2nd October 2018; Revised: 9th November 2018; Accepted: 25th November 2018

Keywords

Ethanol Dehydrogenation; Acetaldehyde; Activated carbon; Coffee ground residues; Lewis acidity and Lewis basicity

  1. Jeerati Ob-eye 
    Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University Center of Excellence on Catalysis and Catalytic Reaction Engineering, Bangkok 10330, Thailand
  2. Piyasan Praserthdam 
    Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University Center of Excellence on Catalysis and Catalytic Reaction Engineering, Bangkok 10330, Thailand
  3. Bunjerd Jongsomjit  Scopus Scholar
    Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University Center of Excellence on Catalysis and Catalytic Reaction Engineering, Bangkok 10330, Thailand