Alcohols hydroperoxide oxidation

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). 

The phenomenon that early transition metals in combination with alkyl hydroperoxides could participate in olefin epoxidation was discovered in the early 1970s [30, 31]. While m-CPBA was known to oxidize more reactive isolated olefins, it was discovered that allylic alcohols were oxidized to the corresponding epoxides at the same rate or even faster than a simple double bond when Vv or MoVI catalysts were employed in the reaction [Eq. (2)] [30]. 

Ketones play an important role in the decomposition of peroxides to form radicals in alcohols undergoing oxidation. The formed hydroxyhydroperoxide decomposes to form radicals more rapidly than hydrogen peroxide. With an increase in the ketone concentration, there is an increase in the proportion of peroxide in the form of hydroxyhydroperoxide, with the corresponding increase in the rate of formation of radicals. This was proved by the acceptor radical method in the cyclohexanol-cyclohexanone-hydrogen peroxide system [59], The equilibrium constant was found to be K — 0.10 L mol 1 (373 K), 0.11 L mol 1 (383 K), and 0.12 L mol 1 (393 K). The rate constant of free radical generation results in the formation of cyclohexylhydroxy hydroperoxide decomposition and was found to be ki = 2.2 x 104 exp(—67.8/7 7) s 1 [59]. 

Bashkirov A process for making aliphatic alcohols by oxidizing paraffins. The reaction is conducted in the presence of boric acid, which scavenges the hydroperoxide intermediates. Borate esters of secondary alcohols are formed as intermediates and then hydrolyzed. Developed in the USSR in the 1950s and now operated there and in Japan. 

As shown in Table 12,H202 and fBuOOH have been used frequently as oxygen donors in peroxidase-catalyzed sulfoxidations. Other achiral oxidants, e.g. iodo-sobenzene and peracids, are not accepted by enzymes and, therefore, only racemic sulfoxides were found (c.f. entries 34-36). Interestingly, racemic hydroperoxides oxidize sulfides to sulfoxides enantioselectively under CPO catalysis [68]. In this reaction, not only the sulfoxides but also the hydroperoxide and the corresponding alcohol were produced in optically active form by enzyme-catalyzed kinetic resolution (cf. Eq. 3 and Table 3 in Sect. 3.1). 

Biological. Dodecane may biodegrade in two ways. The first is the formation of dodecyl hydroperoxide which decomposes to 1-dodecanol. The alcohol is oxidized forming dodecanoic acid. The other pathway involves dehydrogenation to 1-dodecene, which may react with water, giving 1-dodecanol (Dugan, 1972). 

CHO - COOH. This hydroperoxide oxidizes aldehydes to carboxyjic acids in generally satisfactory yields. The oxidation is conducted in CH2Cl2Na2C03 or C lljOll-NaOH. The oxidant does not attack alcohols. The oxidation, as in epoxidations with 1, can be effected with H202 and a catalytic amount of 1. 

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. 

Samra BK, Andersson M, Adlercreutz P (1999) Chloroperoxidase catalysed oxidation of benzyl alcohol using tert-butyl hydroperoxide oxidant in organic media. Biocatal Biotransfor 17 381-391... 

Oxidation. Oxidations with r-butyl hydroperoxide catalyzed with this Mo complex can be used to effect selective oxidations of secondary alcohols in the presence of primary ones in benzene at 60°. Primary alcohols are oxidized slowly to esters in methanol. Aldehydes are oxidized to carboxylic acids in benzene or to esters in methanol. 

Several procedures for this chemoselective oxidation utilize molybdenum-based catalysts, with either hydrogen peroxide or r-butyl hydroperoxide as the stoichiometric oxidant. These include ammonium molybdate in the presence of a ph e transfer reagent and hydrogen peroxide, which with pH control (potassium carbonate) will selectively oxidize a secondary alcohol in the presence of a primary alcohol without oxidizing alkenes. In addition hindered alcohols are oxidized in preference to less hindered ones (Scheme 18). 

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... 

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). 

The oxidation of alcohols to aldehydes can also be accomplished by benzeneseleninic anhydride, (0 115860)20, either as such [525] or prepared in situ from diphenyldiselenide, (0 115)2862, and rert-butyl hydroperoxide [1140]. Benzylic alcohols are oxidized more rapidly than allylic... 

Another approach to designing shape-selective heterogeneous oxidation catalysts was to use redox metal oxides as the pillaring agents in the preparation of pillared clays. These redox pillared clays have been used for a number of selective oxidations. Chromium pillared montmorillonite (Cr-PILC) is an effective catalyst for the selective oxidation of alcohols with tert-butyl hydroperoxide. 7 Primary aliphatic and aromatic alcohols are oxidized to the aldehydes in very good yields. Secondary alcohols are selectively oxidized in the presence of a primary hydroxy group of a diol to give keto alcohols in excellent yields (Eqn. 21.12). 2... 

In contrast to the lack of selectivity observed in the TS-1 catalyzed oxidation of 3-penten-2-ol (1) (Eqn. 21.5), the oxidation of 1 with tert-butyl hydroperoxide (TBHP) over Cr-PILC gave the unsaturated ketone, 3, in 82% yield (Eqn. 21.13)42 while the oxidation of 1 over a vanadium pillared montmorillonite (V-PILC) gave the epoxy alcohol, 2, in 94% yield.43 V-PILC, however, does promote the oxidation of primary benzyl alcohols to the acids with tert-butyl hydroperoxide. This reaction exhibits shape selectivity in that para-substituted benzyl alcohols are oxidized while the ortho- and meta- substituted species are essentially inert (Eqn. 21.14).44... 

The Cr-PILC catalyzed benzylic and allylic oxidations also provide a facile approach to the oxidative deprotection of allyl and benzyl ethers and amines. Treatment of allyl or benzyl ethers with one equivalent of tert-butyl hydroperoxide in the presence of Cr-PILC at room temperature resulted in the oxidative cleavage of the allyl- or benzyl-oxygen bond to give the alcohol but when two equivalents of tert-butyl hydroperoxide (TBHP) were used, the alcohol was oxidized further to the aldehyde or ketone (Eqn. 21.21).47 Oxidation of allyl amines resulted in the cleavage of the allyl-nitrogen bond to give the des-allyl amine.47 Benzyl amines, however, were oxidized to the benzamides (Eqn. 21.22).45... 

The rate is first order with respect to allyl alcohol, Ti(tartrate), and the hydroperoxide oxidizing agent, and is inhibited by alcohol. The rate expression is consistent with the reaction sequence (Fig. 1.17). The Ti(tartrate) complex is formed by removal of two alkoxide ligands, and then the remaining two alkoxide ligands are displaced by TBHP and the allyl alcohol. The order of displacement is immaterial so fhe "loaded complex can be reached by either pathway shown. 

Pentyl-hydroperoxide was prepared from the corresponding alcohol by oxidation with 50% H2O2 in the presence of 85% H3PO4 at 60°C for 6 h to give the hydroperoxide in 48% yield, which was then treated with Pb(OAc)4 in pentane under reflux for 18-45 h to generate 1,2-dioxepane (5) in 10-14% yield (Equation (1)) <81S633>. 

---