4312-76-9Relevant articles and documents
Fenton-Inspired C-H Functionalization: Peroxide-Directed C-H Thioetherification
Groendyke, Brian J.,Modak, Atanu,Cook, Silas P.
, p. 13073 - 13091 (2019/10/10)
Substoichiometric iron mediates the thioetherification of unactivated aliphatic C-H bonds directed by resident silylperoxides. Upon exposure to a catalytic amount of iron(II) triflate, TIPS-protected peroxides bearing primary, secondary, and tertiary C-H sites undergo chemoselective thioetherification of remote C-H bonds with diaryl disulfides. The reaction demonstrates a broad substrate scope and functional group tolerance without the use of any noble metal additives. Mechanistic experiments suggest that the reaction proceeds through 1,5-H atom abstraction by a hydroxyl radical generated with iron.
Synthesis of alkyl hydroperoxides via alkylation of gem -dihydroperoxides
Kyasa, Shivakumar,Puffer, Benjamin W.,Dussault, Patrick H.
, p. 3452 - 3456 (2013/06/26)
2-Fold alkylation of 1,1-dihydroperoxides, followed by hydrolysis of the resulting bisperoxyacetals, provides a convenient method for synthesis of primary and secondary alkyl hydroperoxides.
Process and catalyst for oxidation of hydrocarbons
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Page/Page column 5-6, (2008/06/13)
A process for the oxidation of hydrocarbons comprises contacting the hydrocarbon with an oxygen-containing gas in the presence of a catalyst comprising a microporous solid support, preferably a zeolite, having from 8- to 12-ring open windows and comprising non-framework metal cations selected from manganese, iron, cobalt, vanadium, chromium, copper, nickel, and ruthenium, and mixtures thereof, providing that the oxygen-containing gas does not contain significant amounts of added hydrogen. The catalyst is novel and forms part of the invention. The process may be used for oxidation of alkanes, cycloalkanes, benzene and alkylbenzenes, and is suitable for use in regioselective terminal oxidation of straight chain alkanes and for selective oxidation/separation of p-dialkylbenzenes from an alkylbenzene mixture, for example, p-xylene from an isomeric mixture of xylenes.
Catalytic oxidation of n-hexane on Mn-exchanged zeolites: Turnover rates, regioselectivity, and spatial constraints
Zhan, Bi-Zeng,Moden, Bjoern,Dakka, Jihad,Santiesteban, Jose G.,Iglesia, Enrique
, p. 316 - 325 (2008/03/13)
The effects of channel structure and spatial constraints on n-hexane oxidation rates and regioselectivity were examined on Mn cations within channels of acidic zeolites. Active Mn cations were placed at exchange sites within channels in 8-membered (ZSM-58), 10-membered (ZSM-5 and ZSM-57), and 12-membered ring (MOR) channels by sublimation of MnI2. Synthesis rates for hexanols (ROH), hexanal/hexanones (R({single bond}H){double bond, long}O), and acids were proportional to hexylhydroperoxide (ROOH) concentrations on all Mn-zeolite catalysts, except Mn-ZSM-58, on which products formed exclusively via noncatalytic autoxidation because of restricted access to Mn cations present within small channels (0.36 nm). Catalytic decomposition of ROOH intermediates occurs on intrachannel Mn cations and is the kinetically relevant step in alkane oxidation. ROOH decomposition rate constants were 2.5, 1.4, and 0.41 mol (mol-Mn h)-1 (mM-ROOH)-1 on Mn-ZSM-5, Mn-ZSM-57, and Mn-MOR (403 K; 0.4 MPa O2), respectively. Regioselectivity was influenced by the constrained environment around Mn cations, which increased terminal selectivities above the values predicted from the relative bond energies of methyl and methylene C{single bond}H bonds in n-hexane. Mn cations within 10-ring channels gave higher terminal selectivities (Mn-ZSM-5: 24%, kprim / ksec = 0.42; Mn-ZSM-57: 14%, kprim / ksec = 0.22) than those within 8-membered or 12-membered rings (Mn-MOR, Mn-ZSM-57: 8-10%, kprim / ksec = 0.12 - 0.14), because of restricted access in ZSM-58 and unconstrained transition states for C{single bond}H bond activation in MOR. Terminal selectivities decreased with increasing alkane conversion, because unselective noncatalytic autoxidation pathways prevail as ROOH concentrations concurrently increase. ROOH intermediates can be scavenged from the extracrystalline liquid phase using H-zeolites with accessible protons, which inhibit unselective noncatalytic reactions and maintain higher terminal selectivities as conversion increases, albeit with a concomitant decrease in the rate of oxidation steps also involving ROOH intermediates.
Oxidations by the reagent "O2-H2O2-vanadium derivative-pyrazine-2-carboxylic acid". Part 12. Main features, kinetics and mechanism of alkane hydroperoxidation
Shul'pin, Georgiy B.,Kozlov, Yuriy N.,Nizova, Galina V.,Suess-Fink, Georg,Stanislas, Sandrine,Kitaygorodskiy, Alex,Kulikova, Vera S.
, p. 1351 - 1371 (2007/10/03)
Various combinations of vanadium derivatives (n-Bu4NVO3 is the best catalyst) with pyrazine-2-carboxylic acid (PCA) catalyse the oxidation of saturated hydrocarbons, RH, with hydrogen peroxide and air in acetonitrile solution to produce, at temperatures V(PCA)(H2O2) → VIV(PCA) + HOO. + H+. The VIV species thus formed reacts further with a second H2O2 molecule to generate the hydroxyl radical according to the equation VIV(PCA) + H2O2 → VV(PCA) + HO. + HO-. The concentration of the active species in the course of the catalytic process has been estimated to be as low as [V(PCA)H2O2] ≈ 3.3 × 10-6 mol dm-3. The effective rate constant for the cyclohexane oxidation (d[ROOH]/dt = keff[H2O2]0[V]0) is keff = 0.44 dm3 mol-1 s-1 at 40 °C, the effective activation energy is 17 ± 2 kcal mol-1. It is assumed that the accelerating role of PCA is due to its facilitating the proton transfer between the oxo and hydroxy ligands of the vanadium complex on the one hand and molecules of hydrogen peroxide and water on the other hand. For example: (pca)(O=)V ... H2O2 → (pca)(HO-)V-OOH. Such a "robot's arm mechanism" has analogies in enzyme catalysis.
Intramolecular H-Transfer Reactions During the Decomposition of Alkylhydroperoxides in Hydrocarbons as the Solvents
Jinsheng, Li,Pritzkow, Wilhelm,Voerckel, Volkmar
, p. 43 - 52 (2007/10/02)
Eight defined primary and secondary alkylhydroperoxides were decomposed in n-alkanes as the solvent, mostly in the presence of manganese stearate.In all cases the corresponding alcohols and carbonyl compounds were formed as the main products with yields of 60-90percent.Besides, difunctional products were formed by an intramolecular H-transfer in the alkoxy radicals corresponding to the starting hydroperoxides.Products possibly formed by an intramolecular H-transfer in the corresponding alkylperoxy radical could be found only in the case of 4-methyl-2-hydroperoxy pentane.The amount of products formed by intramolecular H-transfer depended on the nature of the C-H bond in δ-position to the original hydroperoxy group and lay between 4percent (primary C-H in the case of 4-hydroperoxy heptane) and 13percent (tertiary C-H in the case of 2-hydroperoxy-5-methyl hexane) with respect to the starting hydroperoxide.The amount of products formed by oxidative attack of the alkoxy and alkylperoxy radicals at the normal paraffins used as the solvents was unexpectedly low (always less than 10percent with respect to the starting hydroperoxide).An increment system is proposed for the calculation of 13C-nmr shifts in alkyl hydroperoxides.
ORGANOBORANES FOR SYNTHESIS. 6. A CONVENIENT, GENERAL SYNTHESIS OF ALKYLHYDROPEROXIDES via AUTOXIDATION OF ORGANOBORANES
Brown, Herbert C.,Midland, M. Mark
, p. 4059 - 4070 (2007/10/02)
The low temperature autoxidation of organoboranes in tetrahydrofuran leads to the formation of diperoxyboranes, which provide the corresponding alkylhydroperoxides in excellent yields, upon treatment with hydrogen peroxide.However, only two of the three alkyl groups on boron are used for the formation of hydroperoxides.This difficulty was solved by employing alkyldichloroborane etherates instead of trialkylboranes.The alkyldichloroborane etherates react cleanly with one molar equivalent of oxygen in ether solvent.The product is readily hydrolyzed to form the corresponding hydroperoxides in excellent yields.The autoxidation of organoboranes is inhibited by iodine or such free-radical scavengers.A study of the inhibition by iodine of the oxidation of representative trialkylboranes indicates that the rate of initiation decreases with an increase in the steric crowding about the boron atom.The rate of inhibition of the autoxidation of trialkylboranes by iodine reveals that the reaction involves a relatively slow rate of radical initiation, followed by a very fast rate of chain propagation.
