Oxidation of tetralin

The most important process to produce 1-naphthalenol was developed by Union Carbide and subsequently sold to Rhc ne-Poulenc. It is the oxidation of tetralin, l,2,3,4-tetrahydronaphthalene/719-64-2] in the presence of a transition-metal catalyst, presumably to l-tetralol—1-tetralone by way of the 1-hydroperoxide, and dehydrogenation of the intermediate ie, l-tetralol to 1-tetralone and aromatization of 1-tetralone to 1-naphthalenol, using a noble-metal catalyst (58). 1-Naphthol production in the Western world is around 15 x 10 t/yr, with the United States as the largest producer (52). 

Polymer-supported catalysts often have lower activities than the soluble catalysts because of the intraparticle diffusion resistance. In this case the immobilization of the complexes on colloidal polymers can increase the catalytic activity. Catalysts bound to polymer latexes were used in oxidation reactions, such as the Cu-catalyzed oxidation of ascorbic acid,12 the Co-catalyzed oxidation of tetralin,13 and the CoPc-catalyzed oxidation of butylphenol14 and thiols.1516 Mn(III)-porphyrin bound to colloidal anion exchange resin was... 

Howard and Ingold studied this equilibrium reaction in experiments on the oxidation of tetralin and 9,10—dihydroanthracene in the presence of specially added triphenylmethyl hydroperoxide[41]. They estimated the equilibrium constant K to be equal to 60 atm-1 (8 x 103 L mol-1, 303 K). This value is close to T=25atm-1 at 300 K (A/7=38kJ mol-1), which was found in the solid crystal lattice permeable to dioxygen [84], The reversible addition of dioxygen to the diphenylmethyl radical absorbed on MFI zeolite was evidenced and studied recently by the EPR technique [85],... 

Aryl phosphites inhibit the initiated oxidation of hydrocarbons and polymers by breaking chains on the reaction with peroxyl radicals (see Table 17.3). The low values of the inhibition coefficient / for aryl phosphites are explained by their capacity for chain autoxidation [14]. Quantitative investigations of the inhibited oxidation of tetralin and cumene at 338 K showed that with increasing concentration of phosphite /rises tending to 1 [27]. 

During the chain oxidation of hydrocarbons, sulfides and disulfides terminate chains by reacting with peroxyl radicals [40,42,44], which, as opposed to phenols, are weak inhibitors (see Table 17.6). The mechanism and stoichiometry of the termination reaction by sulfides remain yet unclear. Since sulfenic acid is an efficient scavenger of free radicals, the oxidation of tetralin in the presence of dialkylsulfoxide occurs only if the initiation rate v > vimin is proportional to the concentration of sulfoxide [5], so that the rate of oxidation is... 

Tetralin hydroperoxide has little or no effect on the thermally or photochemically initiated oxidation of Tetralin, nor are the absolute rate constants for the oxidation of Tetralin (1.7M in chlorobenzene) affected by adding 0.1M [TOOH] (Table I). [Hydrogen-bonded peroxy radicals are either unimportant in this system or have the same reactivity as the peroxy radicals formed in the absence of hydroperoxide. A similar conclusion applies to propagation in cumene and cumene-COOH mixtures (see Table I).]... 

Reactivity ratios for all the combinations of butadiene, styrene, Tetralin, and cumene give consistent sets of reactivities for these hydrocarbons in the approximate ratios 30 14 5.5 1 at 50°C. These ratios are nearly independent of the alkyl-peroxy radical involved. Co-oxidations of Tetralin-Decalin mixtures show that steric effects can affect relative reactivities of hydrocarbons by a factor up to 2. Polar effects of similar magnitude may arise when hydrocarbons are cooxidized with other organic compounds. Many of the previously published reactivity ratios appear to be subject to considerable experimental errors. Large abnormalities in oxidation rates of hydrocarbon mixtures are expected with only a few hydrocarbons in which reaction is confined to tertiary carbon-hydrogen bonds. Several measures of relative reactivities of hydrocarbons in oxidations are compared. 

The results of a similar study of the inhibited oxidation of Tetralin at 70 °C. are shown in Figures 4 to 6. Again, the initial oxidation rate is... 

The Jones reagent851 and < rt-BuOOH in the presence of chromium(VI) complexes852,853 were found to be particularly useful in the oxidation of tetralins and indans. Oxidation with 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) occurs with an exceptional mechanism.854 In contrast with the radical processes observed in other oxidations DDQ generates a carbocation by hydride abstraction that is trapped by water to form an alcohol ... 

Apart from their proven activity in alkylaromatic oxidations [11] we have also found they possess some activity in the oxidation of tetralin (Figure 7). The oxidation of tetralin is typically carried out at very high temperatures using unstable metal forms of ion exchange resins. 

Fig. 1. Oxidation of tetralin by a) photocatalysis 1-tetralone (A) 2-tetralone (B) C02 (C) - b) photochemistry (i.e. without Ti02) 1-tetralone (A1) 2-tetralone (B1).

Scheme 5.22 Oxidation of tetralin with the manganese-porphyrine catalyst 50...

FIGURE 43 Monolithic stirrer equipped with MIL101(Cr)-coated cordierite monoliths (left) and the performance as a function of time on stream in the oxidation of tetralin with t-butyl peroxide (720). 

Small but significant effects of solvent polarity were found in the autoxidation of a variety of alkenes and aralkyl hydrocarbons [216-220] (styrene [216, 218, 219], ethyl methyl ketone [217], cyclohexene [218], cumene [218, 219], tetralin [219], etc.). An extensive study on solvent effects in the azobisisobutyronitrile (AIBN)-initiated oxidation of tetralin in a great variety of solvents and binary solvent mixtures was made by Kamiya et al. [220],... 

Jirackova, U and Pospisil. J.. Antioxidativc activity of phenols containing. subsiituenLs with hclcroatoms O, S and N in the oxidation of tetralin. Collect. Czech. Chem. Commun., 40, 2800, 1975. 

Yamamura and coworkers used an oxygen absorption method to study the effects of a series of 46 dihydric phenols on inhibition of azo-initiated oxidation of tetralin . They reported activities in terms of the stoichiometric factor, n, and the rate of oxygen absorption, during induction periods. The 13 catechols studied all showed higher n factors (n = 2.0-2.3) and lower values than any other of the diols. Unfortunately, they were not able to obtain values. 

The second method proposed by Ishii uses hydroperoxides from the in situ NHPTcatalyzed oxidation of tetralin or ethylbenzene to epoxidize olefins directly by means of Mo(CO)6 [18] (Scheme 6.2). 

Figure 4.4 shows the retardation of oxidation by a copper salt during the oxidation of tetralin, a model hydrocarbon, in the presence of 0.5% iron stearate [22]. 

Fig. 4.4 Influence of copper stearate on the oxidation rate of the iron stearate (0.5%)-catalysed oxidation of tetralin [22]...

However, Boozer and Hammond [7] have obtained additional support for the postulated chain termination via reaction (9) as opposed to reaction (5) on the basis of isotopic labelling experiments and from the inhibiting effect of amines not possessing a labile N—H function in their structure [8]. The use of deuterium-labelled methyl aniline and diphenyl-amine as inhibitors in the oxidation of tetralin and cumene did not show the isotope effect which would be expected if reaction (5) was important. Similarly, both AT-dimethylaniline and AT,AP-tetramethyl-p-phenylene-diamine have measurable inhibitory activity despite the fact that neither has a labile hydrogen [8]. However, it has been argued [12] that neither a kinetic isotope effect nor a labile hydrogen is necessary if inhibition results from an electron transfer reaction of the type... 

Thus, 1 seems to be a true catalyst rather then a new kind of free radical initiator. This behavior is in contrast to the behavior of related manganese complexes. For example, Mn(II) carboxylates are known to decompose CHP during autoxidation of cumene l dinuclear Mn(III) complexes decompose tetralin hydroperoxide during oxidation of tetralin (an inner-sphere Mn-alkyl hydroperoxide intermediate has been proposed) trinuclear, carboxylate and oxo-bridged complexes containing Mn(II) were found to decompose CHP during the catalyzed oxidation of cumene. 

A classical example of this behavior is the oxidation of tetralin to a-hydroperoxide and tetralol by dioxygen catalyzed by cobalt(II) acetate [68] and cobalt(11)-pyridine complexes [69]. 

The acetylacetonate complexes of cobalt(II) and manganese(111) are efficient catalysts for the thermally intiated oxidation of tetralin, but do not influence the photoinitiated process. The reverse situation is observed for the iron(III) and cobalt(III) complexes [70a]. The thermal oxidation can be influenced by the addition of free-radical initiators like t-butyl hydroperoxide or 2,2 -azobisisobutyronitrile [70b]. 

The oxidation of tetralin leads to the hydroperoxide, which can be split into 1-tetralone and 1-tetralol. Dehydrogenation of tetralone and tetralol takes place in two stages, to avoid the possible dehydration of tetralol on the platinum catalyst. In the first stage, tetralol is dehydrogenated to tetralone in the gas phase in the presence of hydrogen at 200 to 325 °C and nickel or copper catalysts in the second stage, dehydrogenation on the platinum catalyst at 350 to 400 °C produces 1-naphthol. 

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