5779-94-2Relevant articles and documents
A green approach for aerobic oxidation of benzylic alcohols catalysed by CuI-Y zeolite/TEMPO in ethanol without additional additives
Senthilkumar, Samuthirarajan,Zhong, Wei,Natarajan, Mookan,Lu, Chunxin,Xu, Binyu,Liu, Xiaoming
, p. 705 - 713 (2021/01/25)
An efficient and green protocol for aerobic oxidation of benzylic alcohols in ethanol using CuI-Y zeolite catalysts assisted by TEMPO (TEMPO = 2,2,6,6-tetramethyl-1-piperidine-N-oxyl) as the radical co-catalyst in the presence of atmospheric air under mild conditions is reported. The CuI-Y zeolite prepared via ion exchange between CuCl and HY zeolite was fully characterized by a variety of spectroscopic techniques including XRD, XPS, SEM, EDX and HRTEM. The incorporation of Cu(i) into the 3D-framework of the zeolite rendered the catalyst with good durability. The results of repetitive runs revealed that in the first three runs, there was hardly a decline in activity and a more substantial decrease in yield was observed afterwards, while the selectivity remained almost unchanged. The loss in activity was attributed to both the formation of CuO and the bleaching of copper into the liquid phase during the catalysis, of which the formation of CuO was believed to be the major contributor since the bleaching loss for each run was negligible (2%). In this catalytic system, except TEMPO, no other additives were needed, either a base or a ligand, which was essential in some reported catalytic systems for the oxidation of alcohols. The aerobic oxidation proceeded under mild conditions (60 °C, and 18 hours) to quantitatively and selectively convert a wide range of benzylic alcohols to corresponding aldehydes, which shows great potential in developing green and environmentally benign catalysts for aerobic oxidation of alcohols. The system demonstrated excellent tolerance against electron-withdrawing groups on the phenyl ring of the alcohols and showed sensitivity to steric hindrance of the substrates, which is due to the confinement of the pores of the zeolite in which the oxidation occurred. Based on the mechanism reported in the literature for homogenous oxidation, a mechanism was analogously proposed for the aerobic oxidation of benzylic alcohols catalysed by this Cu(i)-containing zeolite catalyst. This journal is
Production and testing of technical catalysts based on MnO2 for the abatement of aromatic volatile compounds at the laboratory and pilot plant scales
Baldovino-Medrano, Víctor Gabriel,Kartheuser, Beno?t,Gaigneaux, Eric M.
, p. 81 - 92 (2019/04/25)
Shaping is a crucial step to produce technical catalysts that remains as some sort of dark art for catalytic researchers in academia. This contribution discusses aspects concerning the fabrication of technical catalysts based on MnO2 powders ai
A Copper-Benzotriazole-Based Coordination Polymer Catalyzes the Efficient One-Pot Synthesis of (N′-Substituted)-hydrazo-4-aryl-1,4-dihydropyridines from Azines
Kallitsakis, Michael,Loukopoulos, Edward,Abdul-Sada, Alaa,Tizzard, Graham J.,Coles, Simon J.,Kostakis, George E.,Lykakis, Ioannis N.
supporting information, p. 138 - 145 (2017/01/14)
A series of new (N′-substituted)-hydrazo-4-aryl-1,4-dihydropyridines was successfully synthesized via a facile one-pot catalytic pathway utilizing azines and propiolate esters as starting materials and a one-dimensional copper benzotriazole-based coordination polymer as catalyst. In the absence of catalyst, the corresponding 5-substituted 4,5-dihydropyrazoles were formed in moderate to high yields. Fine-tuning of the catalysts allowed us to gain more insights regarding the plausible reaction mechanism. (Figure presented.).
