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Nitrobenzene photocatalytic reduction

On the other hand, the production of desired compounds through reduction of starting material requires the electron donors to be oxidized (reductant). Alcohols are often used not only as a solvent but as the donor to produce useful compounds, e.g., anilines from nitrobenzenes,22) alcohols from aldehydes,23) and secondary amines from the corresponding Schiff bases.24) From the organic synthetic point of view, however, the separation of undesired products, aldehydes or ketones, from the alcohols is necessary unless subsequent reaction processes consume them25,26) or they are easily removed by distillation or other procedures. A recent report has shown that water acts as the electron donor and is converted into 02 in the photocatalytic regio-selective reduction of terpenes mixed with aqueous suspension of Ti02.27,28) It is notable that isolation of the desired product from the reaction mixture is simple in this type of photocatalytic reduction. [Pg.101]

Recently, Imamura et al. (2011) studied the photocatalytic reduction of nitrobenzenes and aminonitrobenzenes to aminobenzenes and diaminobenzenes, respectively. These reactions were conducted in aqueous suspensions of titanium (IV) oxide (Ti02) as catalyst and formic acid or oxalic acid as electron donors using de-aerated and aerated conditions under UV light. [Pg.623]

Flores, S. O., Rios-Bemij, O., Valenzuela, M. A., Cordova, I., Gomez, R., Gutierrez, R. (2007). Photocatalytic reduction of nitrobenzene over titanium dioxide by-product identification and possible pathways. Topics in Catalysis, 44, 507—511. http // dx.doi.org/10.1007/sll244-006-0098-2. [Pg.632]

Photocatalytic Reduction of Nitrobenzenes in Aqueous Suspensions of Ti02 in the Presence of Greener Hole Scavengers... [Pg.285]

Stoichiometric Production of Aminobenzenes and Ketones by Photocatalytic Reduction of Nitrobenzenes in Secondary Alcoholic Suspension of Titanium(IV) Oxide Under Metal-Free Conditions... [Pg.304]

In the photocatalytic reduction of nitrobenzenes, positive holes in the valence band were effectively removed by formic acid and oxalic acid. These hole scavengers are greener sacrificial reagents because they are easily oxidized into CO2, and thus formed CO2 molecules are removed from the liquid phase in the presence of organic acids. The photocatalytic reduction of nitrobenzenes would be more attractive if positive holes are utilized for synthesis of valuable compounds, not for fruitless degradation or mineralization. Utilization of positive holes enables simultaneous production of two valuable reduced and oxidized compounds. In the case of reduction of nitrobenzene using oxalic acid (Eq. 9.15), atom efficiency (AE) [64], which is defined in Eq. 9.16, is calculated to be 23.7 % ... [Pg.304]

Chen S, Zhang H, Yu X, Liu W (2010) Photocatalytic reduction of nitrobenzene by titanium dioxide powder. Chin J Chem 28 21-26... [Pg.316]

Imamura K, Iwasaki S, Maeda T, Hashimoto K, Ohtani B, Kominami H (2011) Photocatalytic reduction of nitrobenzenes to aminobenzenes in aqueous suspensions of titanium(IV) oxide in the presence of hole scavengers under deaerated and aerated conditions. Phys Chem Chem Phys 13 5114-5119... [Pg.317]

Imamura K, Yoshikawa T, Hashimoto K, Kominami H (2013) Stoichiometric production of aminobenzenes and ketones by photocatalytic reduction of nitrobenzenes in secondary alcoholic suspension of titanium(IV) oxide under metal-free conditions. AppI Catal B Environ 134-135 193-197... [Pg.319]

The combination of Ti02 and p-sulfonic acid as co-catalyst has been successfully applied for the reduction of nitrobenzene derivatives in 02-free ethanol solutions to substituted quinolines and tetrahydroquinolines [97]. The ratio of the cyclization products depends on the position or the type of the substituents present on the nitrobenzene employed. A reaction mechanism is proposed comprising the photocatalytic formation of methylanilines and acetaldehyde and their subsequent reaction to quinolines and tetrahydroquinolines via a Schiff base as an intermediate. [Pg.197]

Table 9.2 Photocatalytic chemoselective reduction of various nitrobenzenes to corresponding aminobenzenes (Reproduced from Ref [37] with permission from the Royal Society of Chemistry)... Table 9.2 Photocatalytic chemoselective reduction of various nitrobenzenes to corresponding aminobenzenes (Reproduced from Ref [37] with permission from the Royal Society of Chemistry)...
Table 9.3 Photocatalytic chemoselective reduction of nitrobenzenes to corresponding anilines in 2-propanol suspensions of Ti02 and redox balance of anilines and acetone under deaerated conditions (Reprinted from Ref. [75], Copyright 2013, with permission from Elsevier)... Table 9.3 Photocatalytic chemoselective reduction of nitrobenzenes to corresponding anilines in 2-propanol suspensions of Ti02 and redox balance of anilines and acetone under deaerated conditions (Reprinted from Ref. [75], Copyright 2013, with permission from Elsevier)...

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See also in sourсe #XX -- [ Pg.196 ]




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