Alcohol from hydroperoxides

Phosphoric from phosphorous acid esters Alcohols from hydroperoxides... 

Organic hydroperoxides can be prepared by Hquid-phase oxidation of selected hydrocarbons in relatively high yield. Several cycHc processes for hydrogen peroxide manufacture from hydroperoxides have been patented (84,85), and others (86—88) describe the reaction of tert-huty hydroperoxide with sulfuric acid to obtain hydrogen peroxide and coproduct tert-huty alcohol or tert-huty peroxide. 

Isopropyl Ether. Isopropyl ether is manufactured by the dehydration of isopropyl alcohol with sulfuric acid. It is obtained in large quantities as a by-product in the manufacture of isopropyl alcohol from propylene by the sulfuric acid process, very similar to the production of ethyl ether from ethylene. Isopropyl ether is of moderate importance as an industrial solvent, since its boiling point Hes between that of ethyl ether and acetone. Isopropyl ether very readily forms hazardous peroxides and hydroperoxides, much more so than other ethers. However, this tendency can be controlled with commercial antioxidant additives. Therefore, it is also being promoted as another possible ether to be used in gasoline (33). 

The preparation of neopentyl alcohol from diisobutylene herein described represents an example of acid-catalyzed addition of hydrogen peroxide to a branched olefin, followed by an acid-catalyzed rearrangement of the tertiary hydroperoxide formed. In addition to neopentyl alcohol, there are formed acetone and also small amounts of methanol and methyl neopentyl ketone by an alternative rearrangement of the hydroperoxide. 

A series of reactions with gases have been selected for the rapid quantification of many of the major products from the oxidation of polyolefins. Infrared spectroscopy is used to measure absorptions after gas treatments. The gases used and the groups quantified include phosgene to convert alcohols and hydroperoxides to chloroformates, diazomethane to convert acids and peracids to their respective methyl esters, sulfur tetrafluoride to convert acids to acid fluorides and nitric oxide to convert alcohols and hydroperoxides to nitrites and nitrates respectively. 

C(C=0)C1 group to the precise structure (primary, secondary or tertiary) of the alkyl groups to which it is linked. However, our subsequent work with NO showed that its products are also sensitive to the alkyl structure yet in addition NO reacts with oxidized polymers to give distinctly different products from alcohol and hydroperoxide groups (see below). Consequently the COCl2 products were not explored further. 

NO Reactions. The most informative derivitization reaction of oxidized polyolefins that we have found for product identification is that with NO. The details of NO reactions with alcohols and hydroperoxides to give nitrites and nitrates respectively have been reported previously, and only the salient features are discussed here (23). The IR absorption bands of primary, secondary and tertiary nitrites and nitrates are shown in Table I. After NO treatment, y-oxidized LLDPE shows a sharp sym.-nitrate stretch at 1276 cm-1 and an antisym. stretch at 1631 cm-1 (Fig. 1), consistent with the IR spectra of model secondary nitrates. Only a small secondary or primary nitrite peak was formed at 778 cm-1. NO treatment of y-oxidized LLDPE which had been treated by iodometry (all -OOH converted to -OH) showed strong secondary nitrite absorptions, but only traces of primary nitrite, from primary alcohol groups (distinctive 1657 cm-1 absorption). However, primary products were more prominent in LLDPE after photo-oxidation. 

CH Nj reactions, 382 COClj reactions, 383 free radical addition of hexafluoroacetone, 257 identification of oxidation products CHjNj to measure peracids as peresters, 385 extinction coefficients, 388-389/ iodometry to measure -OOH, 385 NO to measure alcohols and hydroperoxides, 386 residual, simplified carbonyl envelope which results from SF exposure, 386... 

The study of the interaction of hydroperoxide with other products of hydrocarbon oxidation showed the intensive initiation by reactions of hydroperoxide with formed alcohols, ketones, and acids [6,134]. Consequently, with the developing of the oxidation process the variety of reactions of initiation increases. In addition to reactions of hydroperoxide with the hydrocarbon and the bimolecular reaction of ROOH, reactions of hydroperoxide with alcohol and ketone formed from hydroperoxide appear. The values of rate constants (in L mol 1 s 1) of these reactions for three oxidized hydrocarbons are given below. 

The kinetic equation rules out the possibility that an oxo species is generated first from hydroperoxide and titanium, which then reacts further with allyl alcohol. At the least, it would be highly coincidental to find these kinetics (the distinct formation of oxo species has been invoked in osmium-catalysed oxidations, as we will see in Chapter 14.3). 

The existence of a facile epoxidation of II at a more rapid rate than that of TME is of interest in relation to a possible intermolecular pathway for formation of an epoxy alcohol from an allylic hydroperoxide during olefin oxidation. When a solution of II (0.01 mole) in TME (0.09 mole) was treated with tert-butyl hydroperoxide (0.01 mole) in the presence of... 

The allyloxy radicals generated from hydroperoxide, dialkyl peroxide and cyclic peroxide intermediates, in accordance with Reactions 6, 9, and 10, respectively, are converted to allyl alcohol moieties, as shown in Reaction 7. The latter are particularly susceptible to reaction with hydrogen chloride. 

Phosphites are known to act by a preventive mechanism, i.e. preventing the formation of initiating radicals from hydroperoxides by reducing the latter to alcohols, see reaction 4 [20]. In addition to their peroxidolytic activity (PD), sterically hindered aromatic phosphites, e.g. Ultranox U626, act also by chain breaking (CB) mechanism. These phosphites react with the propagating alkylperoxyl (ROO ), reactions 5, and alkoxyl (RO) radicals, reactions... 

The direction of the attack is decided by the stereochemistry of diethyl tartrate in the reaction. The ester groups of tartrate molecules extend outward from the ring, thus limiting the manner in which the allylic alcohol and hydroperoxide can bind to the metal. 

This propagation of the hydroperoxide is of great importance because it produces both the ketone and alcohol from the start of the reaction. As soon as Q=0 (cyclohexanone) is formed, an autoacceleration effect is observed, due to the reaction ROOH + Q = O RO + = O + H2O... 

Among the reactions catalyzed by titanium complexes, the asymmetric epoxidation of allylic alcohols developed by Sharpless and coworkers [752, 807-810] has found numerous synthetic applications. Epoxidation of allylic alcohols 3.16 by ferf-BuOOH under anhydrous conditions takes place with an excellent enantioselectivity (ee > 95%) when promoted by titanium complexes generated in situ from Ti(0/ -Pr)4 and a slight excess of diethyl or diisopropyl (R,R)- or (iS, 5)-tartrates 2.69. The chiral complex formed in this way can be used in stoichiometric or in catalytic amounts. For catalytic use, molecular sieves must be added. Because both (RJ )- and (5,5)-tartrates are available, it is posable to obtain either enantiomeric epoxide from a single allylic alcohol. Cumene hydroperoxide (PhCMe20OH) can also be used in place of ferf-BuOOH. This method has been applied to industrial synthesis of enantiomeric glycidols [811, 812]. 

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