scholarly journals N-Doped TiO2 Prepared from Microwave-Assisted Titanate Nanotubes (NaxH2−xTi3O7): The Effect of Microwave Irradiation during TNT Synthesis on the Visible Light Photoactivity of N-Doped TiO2

2011 ◽  
Vol 115 (10) ◽  
pp. 4000-4007 ◽  
Author(s):  
Hsin-Hung Ou ◽  
Shang-Lien Lo ◽  
Ching-Hui Liao
Keyword(s):  
Microwave Irradiation ◽  
Visible Light ◽  
Titanate Nanotubes ◽  
Doped Tio2 ◽  
Microwave Assisted

Microwave-assisted ionic liquid synthesis of Ti3+ self-doped TiO2 hollow nanocrystals with enhanced visible-light photoactivity

2016 ◽  
Vol 191 ◽  
pp. 94-105 ◽  
Author(s):  
Yu Chen ◽  
Weizun Li ◽  
Jingyu Wang ◽  
Yalan Gan ◽  
Le Liu ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Visible Light ◽  
Doped Tio2 ◽  
Microwave Assisted

Modification and characterization of microwave assisted N doped TiO2 – a photodegradation study under suspension and immobilized system

2015 ◽  
Vol 52 (1) ◽  
pp. 51-63 ◽  
Author(s):  
W. I. Nawawi ◽  
M. S. Azami ◽  
L. S. Ang ◽  
M. A. M. Ishak ◽  
K. Ismail
Keyword(s):  
Microwave Irradiation ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Band Gap Energy ◽  
Conventional Heating ◽  
Spectroscopy Analysis ◽  
Doped Tio2 ◽  
Visible Light Active ◽  
Reactive Red 4

A commercially available TiO2 (P25) was modified to produce nitrogen (N) doped TiO2 prepared by mixing TiO2 powder with various amounts of urea as N precursor using a microwave irradiation heating technique. X-ray photoelectron spectroscopy analysis showed that N chemically bonded with TiO2 produces Ti-N. The measured band gap energy (Eg) of the modified sample was ca. 2.9 eV as detected by UV-Vis/DRS. The optimum modified N doped TiO2 denoted as U3-800 prepared at 230 °C showed an active visible light photoactivity. This observation shows that microwave irradiation is able to form Ti-N at low temperature whereas this previously could not be achieved under conventional heating using a muffle furnace at the same temperature. U3-800 showed visible light active photodegradation for 30, 10 and 5 mg L−1 of reactive red 4, crystal violet and Janus green dyes, respectively, in less than 105 min to complete decolorization under suspension mode while no photocatalytic activity was observed under pristine TiO2 under the same conditions. Immobilization of a U3-800 sample was carried out using DSAT as a thin layer binder and the photoactivity of Immobilize/U3-800/DSAT is comparable with the suspension mode. Surprisingly, immobilized/U3-800 has a strong coating with glass support material and can be continuously used for 30 cycles without affecting photoactivity performance.

Regioselective Synthesis of Potent 4,5,6,7-Tetrahydroindazole Derivatives via Microwave-assisted Vilsmeier-Haack Reaction and their Antioxidant Activity Evaluation

2019 ◽  
Vol 16 (3) ◽  
pp. 194-201 ◽  
Author(s):  
Renu Bala ◽  
Vandana Devi ◽  
Pratibha Singh ◽  
Navjot Kaur ◽  
Pawandeep Kaur ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Microwave Irradiation ◽  
Biological Activities ◽  
Reaction Times ◽  
Conventional Heating ◽  
High Chemical ◽  
Microwave Assisted ◽  
Work Up ◽  
Active Methylene ◽  
By Products

Background: Tetrahydroindazole, a member of the fused-pyrazole system, is a least studied class of heterocyclic compounds owing to its scarcity in nature. However, a large number of synthetically prepared tetrahydroindazoles are known to show a variety of biological activities such as interleukin- 2 inducible T-Cell kinase inhibitors, AMPA receptor positive allosteric modulators, antitumor, antituberculosis, anti-inflammatory and antimicrobial activities. Vilsmeier-Haack reaction is one of the most important chemical reactions used for formylation of electron rich arenes. Even though Vilsmeier- Haack reaction was studied on a wide variety of hydrazones derived from active methylene compounds, literature lacks the examples of the use of 4-substituted cyclohexanones as a substrate for the synthesis of 4,5,6,7-tetrahydroindazoles. The study of the reaction of Vilsmeier-Haack reagent with hydrazones derived from cyclic keto compounds having active methylene has been considered the interested topic of investigation. In the present study, ethyl cyclohexanone-4-carboxylate was treated with one equivalent of various hydrazines for two hours and the resulted hydrazones were further treated with an OPC-VH reagent (Vilsmeier-Haack reagent isolated from phthaloyl dichloride and N,Ndimethylformamide) afforded 4,5,6,7-tetrahydroindazoles in excellent yields. The synthesized compounds 4a-f and 5a-f were screened for their antioxidant activities using the DPPH radical scavenging assay. The target compounds were synthesized regioselectively using 4+1 approach in excellent yields. A number of experiments using both conventional heating as well as microwave irradiation methods were tried and on comparison, microwave irradiation method was found excellent in terms of easy work up, high chemical yields, shortened reaction times, clean and, no by-products formation. Some of the synthesized compounds showed significant antioxidant activity. The microwave assisted synthesis of 4,5,6,7-tetrahydroindazoles from ethyl cyclohexanone-4-carboxylate has been reported under mild conditions in excellent yield. Easy work up, high chemical yield, shortened reaction times, clean and no by-products formation are the major advantages of this protocol. These advantages may make this method useful for chemists who are interested in developing novel 4,5,6,7-tetrahydroindazole based drugs.

Visible Light Active Ce-doped TiO2 Nanoparticles for Photocatalytic Degradation of Methylene Blue

2016 ◽  
Vol 13 (1) ◽  
pp. 110-116 ◽  
Author(s):  
Rani P. Barkul ◽  
Farah-Naaz A. Shaikh ◽  
Sagar D. Delekar ◽  
Meghshyam K. Patil
Keyword(s):  
Methylene Blue ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Tio2 Nanoparticles ◽  
Doped Tio2 ◽  
Visible Light Active
Sign in / Sign up

Export Citation Format

Share Document