500-22-1Relevant articles and documents
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Suvorov et al.
, (1969)
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Selective photocatalytic oxidation of 3-pyridinemethanol on platinized acid/base modified TiO2
?etinkaya, S?d?ka,Augugliaro, Vincenzo,Garlisi, Corrado,Lewin, Erik,Palmisano, Giovanni,Sá, Jacinto,Yurdakal, Sedat
, p. 4549 - 4559 (2021)
TiO2catalysts, modified with acidic or alkaline solutions and then platinized, were used for the partial photocatalytic oxidation of 3-pyridinemethanol to 3-pyridinemethanal and vitamin B3under environmentally friendly conditions. The reaction took place in water under UVA light and air oxygen. Catalysts were characterized by TEM, photoluminescence, DRIFT-IR, Raman, DRS, XPS, and photocurrent measurements. The photocatalytic activity results show that Pt loading of untreated samples leads to a significant activity improvement (hence product yield) as much as acid and alkaline treatments do. Moreover, the alkaline treated TiO2samples exhibit a further increase in activity after loading with Pt. Pt acts as an electron scavenger promoting electron transfer from the TiO2conduction band, consequently boosting the photogenerated pair numbers available for the reactive process. Photocurrent measurements show that the TiO2photocatalysts' active sites increase significantly after platinization and alkaline/acid treatment. The treated and/or Pt loaded catalysts showed good thermal stability (at least up to 400 °C).
Mild reductive deoximation with TiCl4/NaI reagent system
Balicki,Kaczmarek
, p. 1777 - 1782 (1991)
The application of the TiCl4/NaI reagent system in the reductive cleavage of oximes under mild conditions is reported.
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Schoenberg,A.,Heck,R.F.
, p. 7761 - 7764 (1974)
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Micellar effects on kinetics and mechanism of Vilsmeier–Haack formylation and acetylation with Pyridines
Alyami, Bandar A.,Iqubal, S. M. Shakeel,Khan, Aejaz Abdullatif,Mohammed, Tasneem
, (2022/01/19)
An efficient preparation of Vilsmeier–Haack formylated and acetylated derivatives with pyridine and substituted pyridines has been developed by employing micelles as catalyst. Their kinetic study reveals a phenomenal rate enhancement in anionic SDS, cationic CTAB, and nonionic TX-100 micellar media. The Vilsmeier–Haack reaction follows second order kinetics. Piszkiewicz’s co-operativity model was used to interpret the results in micellar media. The observed activation parameters ΔH and ΔS values were calculated from Eyring’s plots. The main features of this study were easy process, mild reaction conditions and readily available reagents. Graphical abstract: [Figure not available: see fulltext.].
Photoredox-Catalyzed Simultaneous Olefin Hydrogenation and Alcohol Oxidation over Crystalline Porous Polymeric Carbon Nitride
Qiu, Chuntian,Sun, Yangyang,Xu, Yangsen,Zhang, Bing,Zhang, Xu,Yu, Lei,Su, Chenliang
, p. 3344 - 3350 (2021/07/26)
Booming of photocatalytic water splitting technology (PWST) opens a new avenue for the sustainable synthesis of high-value-added hydrogenated and oxidized fine chemicals, in which the design of efficient semiconductors for the in-situ and synergistic utilization of photogenerated redox centers are key roles. Herein, a porous polymeric carbon nitride (PPCN) with a crystalline backbone was constructed for visible light-induced photocatalytic hydrogen generation by photoexcited electrons, followed by in-situ utilization for olefin hydrogenation. Simultaneously, various alcohols were selectively transformed to valuable aldehydes or ketones by photoexcited holes. The porosity of PPCN provided it with a large surface area and a short transfer path for photogenerated carriers from the bulk to the surface, and the crystalline structure facilitated photogenerated charge transfer and separation, thus enhancing the overall photocatalytic performance. High reactivity and selectivity, good functionality tolerance, and broad reaction scope were achieved by this concerted photocatalysis system. The results contribute to the development of highly efficient semiconductor photocatalysts and synergistic redox reaction systems based on PWST for high-value-added fine chemical production.
Partial photocatalytic oxidations of 3-pyridinemethanol and 3-picoline by TiO2 prepared in HCl, HNO3 and H2SO4 at different temperatures
?etinkaya, S?d?ka,Yurdakal, Sedat
, p. 237 - 247 (2020/12/13)
Home prepared TiO2 photocatalysts were prepared from TiCl4 precursor in the absence and presence of HCl (1?6 M), HNO3 (1 M) or H2SO4 (1 M) at room temperature (RT), 60 or 100 °C. The TiO2 catalysts were characterised by XRD, BET, SEM and TGA techniques. TiO2 catalyst could not form at low temperature (up to 60 °C) in the presence of H2SO4. Just rutile phase was obtained for all TiO2 samples prepared at RT and 60 °C in HCl or HNO3. At 100 °C mainly both brookite and rutile phases were obtained in the presence of HCl or HNO3, whilst mainly anatase phase appeared in the presence of H2SO4. Nanorod structured TiO2 was formed in the presence of 1 M HCl or HNO3 at RT and 60 °C. The prepared TiO2 catalysts were used for partial oxidation of 3-pyridinemethanol to 3-pyridinemethanal and vitamin B3 in water under UVA irradiation. Moreover, photocatalytic oxidation of 3-picoline, precursor of 3-pyridinemethanol, was also performed, but much lower product selectivity values were obtained with respect to 3-pyridinemethanol oxidation. However, selective 3-picoline oxidation could be performed at pH 2 with low activity. Degussa P25 was used for comparison and almost all home prepared catalysts showed a higher selectivity, but they showed to be less active than Degussa P25. The high selectivity of the home prepared samples was not due to the type of TiO2 phase, but mainly to the hydrophilicity of the TiO2 surface which allowed desorption of valuable products instead of their over-oxidation.