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Subject: search.filters.subject.Acetaldehyde

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    Role of alkali and alkaline-earth doped in zeolite A-derived from industrial waste toward direct ethanol dehydrogenation to acetaldehyde
    (2026-06-08)
    Sukchit, Darunee
    ;
    Prajuabsuk, Malee
    ;
    Inntam, Chan
    ;
    Lumlong, Saisamorn
    ;
    Pakamwong, Bongkochawan
    In this study, a sustainable catalytic route for converting ethanol into value-added acetaldehyde was developed using alkali- and alkaline earth-modified zeolite A synthesized from sugarcane bagasse ash (SCBA). Zeolite A was first prepared via alkaline fusion followed by hydrothermal crystallization and subsequently doped with 1 wt% K^+ or Ca^2+ using incipient wetness impregnation. Comprehensive physicochemical characterization (X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), Fourier transform infrared spectroscopy (FTIR), nitrogen physisorption (N_2 physisorption), ammonia temperature-programmed desorption (NH_3-TPD), and carbon dioxide temperature-programmed desorption (CO_2-TPD)) confirmed the formation of a highly crystalline LTA framework with tunable acid-base properties upon cation incorporation. Catalytic evaluation demonstrated that ethanol dehydrogenation strongly depends on the balance of surface acid-base sites. The parent and Ca-modified zeolite A exhibited moderate acetaldehyde selectivity (11.2% and 21.2%, respectively), likely due to competing dehydration reactions. In contrast, K-modified zeolite A achieved higher acetaldehyde selectivity (51.8%) at 35.2% ethanol conversion, attributed to enhanced surface basicity and suppressed acidity. Mechanistic analysis suggests that K^+ and Ca^2+ promote ethanol dehydrogenation by facilitating ethoxide formation and β-hydrogen elimination on basic lattice oxygen sites. These findings demonstrate a cost-effective, noble-metal-free catalytic strategy and highlight the potential of SCBA-derived zeolite A as a sustainable platform for green ethanol upgrading.
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    A "dual-acceptor channel" membraneless gas-diffusion unit for simultaneous determination of ethanol and acetaldehyde in liquors using reverse flow injection
    (2018-01-01)
    Choengchan, Nathawut
    ;
    Poontong, Bangerdsuk
    ;
    Mathaweesansurn, Arjnarong
    ;
    Maneerat, Noppadol
    ;
    Motomizu, Shoji
    A new design of membraneless gas-diffusion unit with dual acceptor channels for separation, collection and simultaneous determination of two volatile analytes in liquid sample is presented. The unit is comprised of three parallel channels in a closed module. A sample is aspirated into the central channel and two kinds of reagents are introduced into the other two channels. Two analytes are isolated from the sample matrix by diffusion into head-space and absorbed into the specific reagents. Non-absorbed vapor is released by opening the programmable controlled lid. The unit was applied to liquors for measurement of ethanol and acetaldehyde using reverse flow injection. Dichromate and nitroprusside were exploited as reagents for colorimetric detection of ethanol and acetaldehyde, respectively. Good linearity ranges (r2 > 0.99) with high precision (RSD < 2%) and high accuracy (recovery: 90 - 105%) were achieved. The results were compared to the results by GC-FID and no significant difference was observed by paired t-test (95% confidence).
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    Acetaldehyde production from ethanol over Ni-based catalysts
    (2008-01-01)
    Neramittagapong, Arthit
    ;
    Attaphaiboon, Wiphada
    ;
    Neramittagapong, Sutasinee
    The aim of this work was to study the catalytic ethanol dehydrogenation to acetaldehyde over nickel based catalysts. SnO<inf>2</inf>, Al<inf>2</inf>O <inf>3</inf> and SiO<inf>2</inf> were used as supporting materials. The reactions were carried out in a catalytic flow system operated in the temperature range of 200 and 350°C under atmospheric pressure. Various parameters such as Ni loading, a kind of supporting materials, contact time on the ethanol conversion and selectivity to acetaldehyde were investigated. The main product in all cases is acetaldehyde, with secondary products such as ethyl acetate and diethyl ether. It has been found that Ni/SnO<inf>2</inf> showed the highest ethanol conversion with high selectivity to acetaldehyde. The 10 wt% Ni/SnO<inf>2</inf> exhibited the highest yield of acetaldehyde at 300°C with low contact time (0.05g min ml<sup>-1</sup>). The deactivation of 10 wt% Ni/SnO<inf>2</inf> was occurred after 200 minutes on stream due to the formation of Ni-Sn alloy phase.