Hydroperoxides alcohols

For example, such a photooxygenation of alcohols 569 lead to unsaturated alcohol-hydroperoxides 570, which react with ketones and aldehydes to give 1,2,4-trioxanes 571 characterized by a-styryl-substituents at the 6-position (Scheme Geraniol... 

This work concerns mainly the modification of commercial polymers bearing hydroxy fonctions as alcohol, hydroperoxide or carboxylic acid, by reactive gases or liquid volatil compounds capable to penetrate in the polymer matrix. The modifications of membranes properties as gas permeability or surface tension will also be reported. Few examples will also concern the reaction of double bond with 12 and HBr vapor as well as the oxidation of piperidine group by peracetic acid. 

Treatment of polymer films by reactive gases or reactive volatil compounds allows to easily modify polymers containing alcohols, hydroperoxides, carboxylic acids (or acids halides), double bonds or piperidine groups. New functional groups as organic nitrites, nitrates, iodides, acid halides (Cl, F), amides, esters, peresters and nitroxyl radicals can be generated by a single reaction or by combination of two consecutive treatments. The reactions are very efficient on thin films (ca 50-100 pm) and can be controlled by transmission and reflexion 1R spectroscopy. 

Fourier transform (FT) IR analysis of the photooxidized SAN samples shows that the oxidation products formed in the copolymer may result not only from the oxidation of the styrene units, even in the first few hours of irradiation [11]. Figure 30.4 shows that the absorbance of the carbonylated photoproducts in the photooxidized SAN samples is different compared with PS (Figure 30.1). Substantial evidence for the contribution of the acrylonitrile units in the photooxidation was obtained by chemical and physical treatments carried out on pre-photooxidized samples as described above. For example, the SF4 treatment of a SAN photooxidized sample led to a partial decrease in absorbance in the hydroxyl region, corresponding to the disappearance of alcohols, hydroperoxides and acids. The absorbance remaining after treatment may be assigned to... 

Water, alcohols, hydroperoxides or carboxylates can be added regioselectively to a,/ -unsaturat-ed carbonyl compounds by the oxymercuration demercuration protocol. In this sequence, the oxymercuration step yields the -addition product. Depending on whether the demercura-tion is performed with retention or inversion of configuration, two sets of diastereomeric pairs of enantiomers (racemic mixtures) are obtained. 

Other oxidations with singlet oxygen are conversions of alkenes into epoxides [43, of secondary alcohols into ketones via alcohol hydroperoxides [44, 45] (equation 9) and the oxidative degradation of tertiary amines to secondary amines [46] (equation 10). 

Sodium azide. 18,325-1,2-Azido alcohols. hydroperoxides on irrad (e.g., rhodamine B) in furnishes the azido alco Azides. Benzyli system. Other aliphatic... 

Further evidence for an intermediate hydropero.xide was found in Zn -Fe -superoxide ex periments when PPh3 was added before tlie formation of the superoxide. This did not change the total amount of oxidation (ketone + alcohol), but did dramatically change the ketone to alcohol ratio in favor of alcohol. Hydroperoxides are. of course, rapidly reduced by PPli3 to alcohols. Furthermore when trimethyl phosphite is used instead of PPI13, the products of the reaction are phosphate and ketone. [7] Trimethyl phosphite is a reagent which reduces hydroperoxides at once to alcohols. This new trimethyl phosphite reaction can be understood better when we ask the question how is tlie hydroperoxide fonned ... 

Photolysis is an important atmospheric loss mechanism for aldehydes and ketones. The lifetimes with respect to photolysis of oxygenated compounds are estimated in chapter DC. The atmospheric lifetimes of the alcohols, hydroperoxides, ethers, esters. 

The first practical method for asymmetric epoxidation of primary and secondary allylic alcohols was developed by K.B. Sharpless in 1980 (T. Katsuki, 1980 K.B. Sharpless, 1983 A, B, 1986 see also D. Hoppe, 1982). Tartaric esters, e.g., DET and DIPT" ( = diethyl and diisopropyl ( + )- or (— )-tartrates), are applied as chiral auxiliaries, titanium tetrakis(2-pro-panolate) as a catalyst and tert-butyl hydroperoxide (= TBHP, Bu OOH) as the oxidant. If the reaction mixture is kept absolutely dry, catalytic amounts of the dialkyl tartrate-titanium(IV) complex are suflicient, which largely facilitates work-up procedures (Y. Gao, 1987). Depending on the tartrate enantiomer used, either one of the 2,3-epoxy alcohols may be obtained with high enantioselectivity. The titanium probably binds to the diol grouping of one tartrate molecule and to the hydroxy groups of the bulky hydroperoxide and of the allylic alcohol... 

Because osmium tetraoxide is regenerated m this step alkenes can be converted to vie mal diols using only catalytic amounts of osmium tetraoxide which is both toxic and expensive The entire process is performed m a single operation by simply allowing a solution of the alkene and tert butyl hydroperoxide m tert butyl alcohol containing a small amount of osmium tetraoxide and base to stand for several hours... 

Ether alcohols Ether formation Ether hydroperoxides Etherification... 

Until World War 1 acetone was manufactured commercially by the dry distillation of calcium acetate from lime and pyroligneous acid (wood distillate) (9). During the war processes for acetic acid from acetylene and by fermentation supplanted the pyroligneous acid (10). In turn these methods were displaced by the process developed for the bacterial fermentation of carbohydrates (cornstarch and molasses) to acetone and alcohols (11). At one time Pubhcker Industries, Commercial Solvents, and National Distillers had combined biofermentation capacity of 22,700 metric tons of acetone per year. Biofermentation became noncompetitive around 1960 because of the economics of scale of the isopropyl alcohol dehydrogenation and cumene hydroperoxide processes. 

Production of acetone by dehydrogenation of isopropyl alcohol began in the early 1920s and remained the dominant production method through the 1960s. In the mid-1960s virtually all United States acetone was produced from propylene. A process for direct oxidation of propylene to acetone was developed by Wacker Chemie (12), but is not beheved to have been used in the United States. However, by the mid-1970s 60% of United States acetone capacity was based on cumene hydroperoxide [80-15-9], which accounted for about 65% of the acetone produced. 

Oxidation begins with the breakdown of hydroperoxides and the formation of free radicals. These reactive peroxy radicals initiate a chain reaction that propagates the breakdown of hydroperoxides into aldehydes (qv), ketones (qv), alcohols, and hydrocarbons (qv). These breakdown products make an oxidized product organoleptically unacceptable. Antioxidants work by donating a hydrogen atom to the reactive peroxide radical, ending the chain reaction (17). 

Propylene oxide [75-56-9] is manufactured by either the chlorohydrin process or the peroxidation (coproduct) process. In the chlorohydrin process, chlorine, propylene, and water are combined to make propylene chlorohydrin, which then reacts with inorganic base to yield the oxide. The peroxidation process converts either isobutane or ethylbenzene direcdy to an alkyl hydroperoxide which then reacts with propylene to make propylene oxide, and /-butyl alcohol or methylbenzyl alcohol, respectively. Table 1 Hsts producers of propylene glycols in the United States. 

Usually, organoboranes are sensitive to oxygen. Simple trialkylboranes are spontaneously flammable in contact with air. Nevertheless, under carefully controlled conditions the reaction of organoboranes with oxygen can be used for the preparation of alcohols or alkyl hydroperoxides (228,229). Aldehydes are produced by oxidation of primary alkylboranes with pyridinium chi orochrom ate (188). Chromic acid at pH < 3 transforms secondary alkyl and cycloalkylboranes into ketones pyridinium chi orochrom ate can also be used (230,231). A convenient procedure for the direct conversion of terminal alkenes into carboxyUc acids employs hydroboration with dibromoborane—dimethyl sulfide and oxidation of the intermediate alkyldibromoborane with chromium trioxide in 90% aqueous acetic acid (232,233). 

Carbonyl compounds can be primary (from radicals or hydroperoxides) or secondary (from alcohols). Thus the picture emerges of hydrocarbon oxidations occurring through compHcated series-sequential pathways as in Figure 1, where clearly other reactions could be going on as well. All possible pathways are pursued to some extent traffic along any pathway is a function of energy requirements and relative concentrations. 

Chromium compounds decompose primary and secondary hydroperoxides to the corresponding carbonyl compounds, both homogeneously and heterogeneously (187—191). The mechanism of chromium catalyst interaction with hydroperoxides may involve generation of hexavalent chromium in the form of an alkyl chromate, which decomposes heterolyticaHy to give ketone (192). The oxidation of alcohol intermediates may also proceed through chromate ester intermediates (193). Therefore, chromium catalysis tends to increase the ketone alcohol ratio in the product (194,195). 

An oxirane process utilizes ethylbenzene to make the hydroperoxide, which then is used to make propylene oxide [75-56-9]. The hydroperoxide-producing reaction is similar to the first step of cumene LPO except that it is slower (2,224,316—318). In the epoxidation step, a-phenylethyl alcohol [98-85-1] is the coproduct. It is dehydrated to styrene [100-42-5]. The reported 1992 capacity for styrene by this route was 0.59 X 10 t/yr (319). The corresponding propylene oxide capacity is ca 0.33 x 10 t/yr. The total propylene oxide capacity based on hydroperoxide oxidation of propylene [115-07-1] (coproducts are /-butyl alcohol and styrene) is 1.05 x 10 t/yr (225). 

As of this writing, the process has not been commercialized, but apparendy the alcohol can be separated from its propylene oxide coproduct process to maintain an economically competitive position. The formation of organic hydroperoxides is a concern, as it was in the Shell process. 

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. 

Alkyl hydroperoxides can be Hquids or soHds. Those having low molecular weight are soluble in water and are explosive in the pure state. As the molecular weight increases, ie, as the active oxygen content is reduced, water solubiUty and the violence of decomposition decrease. Alkyl hydroperoxides are stronger acids than the corresponding alcohols and have acidities similar to those of phenols, Alkyl hydroperoxides can be purified through their alkali metal salts (28). 

Bond dissociation energies (BDEs) for the oxygen—oxygen and oxygen— hydrogen bonds are 167—184 kj/mol (40.0—44.0 kcal/mol) and 375 kj/mol (89.6 kcal/mol), respectively (10,45). Heats of formation, entropies, andheat capacities of hydroperoxides have been summarized (9). Hydroperoxides exist as hydrogen-bonded dimers in nonpolar solvents and readily form hydrogen-bonded associations with ethers, alcohols, amines, ketones, sulfoxides, and carboxyhc acids (46). Other physical properties of hydroperoxides have been reported (46). 

Hydroperoxides have been obtained from the autoxidation of alkanes, aralkanes, alkenes, ketones, enols, hydrazones, aromatic amines, amides, ethers, acetals, alcohols, and organomineral compounds, eg, Grignard reagents (10,45). In autoxidations involving hydrazones, double-bond migration occurs with the formation of hydroperoxy—azo compounds via free-radical chain processes (10,59) (eq. 20). 

Other Hydroperoxides. Several hydrotrioxides including alkyl hydrotrioxides, R—OOOH, have been reported (63,64). There is strong spectroscopic evidence that a-cumyl hydrotrioxide [82951-48-2] is produced in the low temperature ozonization of cumene. Homolytic decomposition of a-cumyl hydrotrioxide in cumene/acetone-hindered phenol resulted in cumyl alcohol as the only organic product (65). Based on the... 

The following commercially available dialkyl peroxides are produced according to equations 24—27 di-Z fZ-butyl peroxide from hydrogen peroxide and sulfated tert-huty alcohol or isobutylene dicumyl peroxide from a-cumyl hydroperoxide and cumyl alcohol, cumyl chloride, and/or a-methylstyrene m- and -di(2-/ f2 -butylperoxyisopropyl)ben2ene [2781-00-2] from tert-huty hydroperoxide [75-91-2] and m- and -di(2-hydroxyisopropyl)ben2ene ... 

Secondary alcohols, such as isopropyl alcohol, j -butyl alcohol, 2-pentanol, 3-pentanol, cyclopentanol, and cyclohexanol, have been autoxidized to hydroxyaLkyl hydroperoxides (1, X = OH R = H) (10,44). These autoxidations usually are carried out at ca 20°C with uv radiation in the presence of a photosensitizer, eg, benzophenone. a-Oxygen-substituted dialkyl peroxides (2, X = Y = OH and X = Y = OOH), also are formed and sometimes they are the exclusive products (10). 

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