Maluangnont, Tosapol

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Maluangnont, Tosapol
Alternative Name
Maluangnont, T.
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Email
tosapol.ma@kmitl.ac.th

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    Production of liquid fuel from palmitic acid over nanocrystalline CeO2-based catalysts with minimal use of H2
    (2017-01-01)
    Maluangnont, Tosapol
    ;
    Dararat, Chalinee
    ;
    Kulrat, Teerapong
    ;
    Soontontaweesub, Surachet
    ;
    Anothaiwalaikul, Thitima
    The deoxygenation of palmitic acid into diesel-range hydrocarbons can be promoted over nanocrystalline ceria-based catalysts under atmospheric N<inf>2</inf> or 10% H<inf>2</inf>/N<inf>2</inf> in a fixed-bed flow reactor at 400 °C. Oxygen vacancy sites are active for ketonization of palmitic acid to C<inf>31</inf> ketone and also subsequent cracking of the formed ketone to hydrocarbons. The 22–31% selectivity of C<inf>9</inf> to C<inf>17</inf> liquid hydrocarbons can be achieved at 100% palmitic acid conversion. The deoxygenation under N<inf>2</inf> can be facilitated, presumably by hydrogen transfer from coke precursors. Catalytic activity of ceria-based catalysts can be tuned by pretreatment conditions, type of a carrier gas, or lattice modification.
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    Surface and interlayer base-characters in lepidocrocite titanate: The adsorption and intercalation of fatty acid
    (2016-06-01)
    Maluangnont, Tosapol
    ;
    Arsa, Pornanan
    ;
    Limsakul, Kanokporn
    ;
    Juntarachairot, Songsit
    ;
    Sangsan, Saithong
    While layered double hydroxides (LDHs) with positively-charged sheets are well known as basic materials, layered metal oxides having negatively-charged sheets are not generally recognized so. In this article, the surface and interlayer base-characters of O<sup>2-</sup> sites in layered metal oxides have been demonstrated, taking lepidocrocite titanate K<inf>0.8</inf>Zn<inf>0.4</inf>Ti<inf>1.6</inf>O<inf>4</inf> as an example. The low basicity (0.04 mmol CO<inf>2</inf>/g) and low desorption temperature (50-300 °C) shown by CO<inf>2</inf>- TPD suggests that O<sup>2-</sup> sites at the external surfaces is weakly basic, while those at the interlayer space are mostly inaccessible to CO<inf>2</inf>. The liquid-phase adsorption study, however, revealed the uptake as much as 37% by mass of the bulky palmitic acid (C<inf>16</inf> acid). The accompanying expansion of the interlayer space by ~0.1 nm was detected by PXRD and TEM. In an opposite manner to the external surfaces, the interlayer O<sup>2-</sup> sites can deprotonate palmitic acid, forming the salt (i.e., potassium palmitate) occluded between the sheets. Two types of basic sites are proposed based on ultrafast <sup>1</sup>H MAS NMR and FTIR results. The interlayer basic sites in lepidocrocite titanate leads to an application of this material as a selective and stable two-dimensional (2D) basic catalyst, as demonstrated by the ketonization of palmitic acid into palmitone (C<inf>31</inf> ketone). Tuning of the catalytic activity by varying the type of metal (Zn, Mg, and Li) substituting at Ti<sup>IV</sup> sites was also illustrated.
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    Direct conversion of carboxylic acid to olefins over Pt-loaded, oxygen-deficient alkali hexatitanate catalysts with ketonization-hydrogenation-dehydration activity
    (2021-09-01)
    Promchana, Pratya
    ;
    Boonchun, Adisak
    ;
    T-Thienprasert, Jiraroj
    ;
    Sooknoi, Tawan
    ;
    Maluangnont, Tosapol
    The production of long chain olefins from fatty acids via decarbonylation is limited by low olefins selectivity at high conversion. Here, we reported the direct acid-to-olefins conversion via the ketonization-hydrogenation-dehydration sequence at 400 °C and atmospheric 10 %H<inf>2</inf>/Ar. The oxygen vacancy defects (V<inf>O</inf>) were essential in acetic acid ketonization over the oxygen-deficient alkali hexatitanate A<inf>2</inf>Ti<inf>6</inf>O<inf>13-</inf><inf>x</inf> (A[dbnd]K, Na and Li) catalysts, as evidenced from the activity of reduced vs non-reduced catalysts. The presence of V<inf>O</inf> was deduced spectroscopically with XPS and DRUV-VIS, and the ease of V<inf>O</inf> formation was ranked via the DFT calculations. The ketonization activity was proportionated to the square of the V<inf>O</inf> content (x<sup>2</sup>), consistent with the bimolecular reaction mechanism. The Pt-loaded K<inf>2</inf>Ti<inf>6</inf>O<inf>13-</inf><inf>x</inf> enabled the direct acid-to-olefins transformation as shown by a complete conversion of two model compounds (heptanoic acid and lauric acid) with ∼30–40 % yield of long chain olefins. Heptanoic acid (C<inf>7</inf>) underwent ketonization to 7-tridecanone (a C<inf>13</inf> ketone) prior to the hydrogenation-dehydration to 7-tridecene, a C<inf>13</inf> olefin. The strong metal-support interaction (SMSI) between Pt and K<inf>2</inf>Ti<inf>6</inf>O<inf>13-</inf><inf>x</inf> inhibited further hydrogenation of the olefin to a low-value alkane. For lauric acid (C<inf>12</inf>), 12-tricosene (a C<inf>23</inf> olefin) was produced analogously. The catalytic activity and products selectivity over Pt-loaded K<inf>2</inf>Ti<inf>6</inf>O<inf>13-</inf><inf>x</inf> significantly depended on the Pt content (0–1.0 wt%). The simultaneous C[sbnd]C coupling and oxygen removal prior to the subsequent hydrogenation and dehydration is a potential approach toward the production of long chain olefins with the (2n-1) carbon atoms from C<inf>n</inf>-fatty acids.