Direct conversion of carboxylic acid to olefins over Pt-loaded, oxygen-deficient alkali hexatitanate catalysts with ketonization-hydrogenation-dehydration activity
| dc.contributor.author | Promchana, Pratya | |
| dc.contributor.author | Boonchun, Adisak | |
| dc.contributor.author | T-Thienprasert, Jiraroj | |
| dc.contributor.author | Sooknoi, Tawan | |
| dc.contributor.author | Maluangnont, Tosapol | |
| dc.date.accessioned | 2026-08-06T10:33:34Z | |
| dc.date.available | 2026-08-06T10:33:34Z | |
| dc.date.issued | 2021-09-01 | |
| dc.description.abstract | 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. | |
| dc.identifier.citation | Catalysis Today, 375, 418-428, 2021 | |
| dc.identifier.doi | 10.1016/j.cattod.2020.02.004 | |
| dc.identifier.issn | 09205861 | |
| dc.identifier.other | 2-s2.0-85079527065 | |
| dc.identifier.uri | https://dspace.kmitl.ac.th/handle/123456789/12283 | |
| dc.source | Catalysis Today | |
| dc.subject | Alkali hexatitanate | |
| dc.subject | DFT calculations | |
| dc.subject | Ketonization | |
| dc.subject | Long chain olefins | |
| dc.subject | Platinum | |
| dc.title | Direct conversion of carboxylic acid to olefins over Pt-loaded, oxygen-deficient alkali hexatitanate catalysts with ketonization-hydrogenation-dehydration activity | |
| dc.type | Article |