106498-75-3Relevant academic research and scientific papers
Catalytic performance of bulk and colloidal Co/Al layered double hydroxide with Au nanoparticles in aerobic olefin oxidation
Leandro, Sónia R.,Fernandes, Cristina I.,Viana,Mourato,Vaz, Pedro D.,Nunes, Carla D.
, (2019)
A Co/Al layered double hydroxide material was synthesized in both bulk and exfoliated (colloidal) forms. Anion exchange with methionine allowed immobilization of Au nanoparticles previously prepared by a biomimetic method using an anti-oxidant tea aqueous extract to reduce the Au salt solution. The catalytic performance of bulk and exfoliated clays Au-hybrid materials was assessed in aerobic olefin epoxidation. Both catalysts were very active towards the epoxide products and with very interesting substrate conversion levels after 80 h reaction time. The Au-exfoliated material, where the nanosheets work as large ligands, yielded higher product stereoselectivity in the case of limonene epoxidation. This arises from a confined environment around the Au nanoparticles wrapped by the clay nanosheets modulating access to the catalytic active centres by reagents. Mechanistic assessment was also accomplished for styrene oxidation by DFT methods.
Process for cooxidizing organic compounds, process for producing epoxy compounds and process for producing esters or lactones
-
, (2008/06/13)
According to the inventive co-oxidation process of organic compounds, (A) a compound selected from (A1) a compound having a non-aromatic ethylenic bond and (A2) a ketone or an alcohol corresponding to the ketone is oxidized by molecular oxygen in the presence of N-hydroxyphthalimide or another imide compound and in the coexistence of (B) a compound oxidizable by the imide compound and oxygen and different from the compound (A). As the compound (B), (a) primary or secondary alcohols (e.g., benzhydrol, cyclohexanol), (b) compounds each having a carbon-hydrogen bond at the adjacent position to an unsaturated bond (e.g., tetralin, ethylbenzene) and the like can be used. According to this process, a corresponding epoxy compound from the compound (A1) having a non-aromatic ethylenic bond, and a corresponding ester or lactone from the ketone or its corresponding alcohol (A2) can be obtained in satisfactory yields.
Microwave-assisted oxidation of saturated and unsaturated alcohols with t-butyl hydroperoxide and zeolites
Palombi, Laura,Bonadiesa, Francesco,Scettri, Arrigo
, p. 15867 - 15876 (2007/10/03)
Under microwave irradiation 3? molecular sieves promote the oxidation of secondary (linear and cyclic) and benzylic alcohols to the corresponding carbonyl compounds by t-butyl hydroperoxide. Under the same conditions, α,β-unsaturated alcohols are converted into α,β-epoxyalcohols in regio- and diastereoselective way. Both oxidative processes can be performed under solvent-free conditions; however, epoxidation of allylic alcohols is found to proceed with more satisfactory efficiency in saturated aliphatic hydrocarbon (n-hexane or cyclohexane).
Mechanism of asymmetric epoxidation. 1. Kinetics
Woodard, Scott S.,Finn,Sharpless, K. Barry
, p. 106 - 113 (2007/10/02)
The rate of titanium-tartrate-catalyzed asymmetric epoxidation of allylic alcohols is shown to be first order in substrate and oxidant, and inverse second order in inhibitor alcohol, under pseudo-first-order conditions in catalyst. The rate is slowed by substitution of electron-withdrawing substituents on the olefin and varies slightly with solvent, CH2Cl2 being the solvent of choice. Asymmetric induction suffers when the size of the alkyl hydroperoxide is reduced. Kinetic resolution of secondary allylic alcohols is shown to be sensitive to the size of the tartrate ester group and insensitive to the steric nature of inhibitor alcohol. Most importantly, the species containing equimolar amounts of Ti and tartrate is shown to be the most active catalyst in the reaction mixture, mediating reaction at much faster rates than titanium tetraalkoxide alone.
