Oxidation of benzoic acid

The three chemical reactions in the toluene—benzoic acid process are oxidation of toluene to form benzoic acid, oxidation of benzoic acid to form phenyl benzoate, and hydrolysis of phenyl benzoate to form phenol. A typical process consists of two continuous steps (13,14). In the first step, the oxidation of toluene to benzoic acid is achieved with air and cobalt salt catalyst at a temperature between 121 and 177°C. The reactor is operated at 206 kPa gauge (2.1 kg/cm g uge) and the catalyst concentration is between 0.1 and 0.3%. The reactor effluent is distilled and the purified benzoic acid is collected. The overall yield of this process is beheved to be about 68 mol % of toluene. 

The hydroxyl group of the resulting phenol is situated immediately adjacent to where the carboxyl group was previously located. This same Hquid-phase copper oxidation process chemistry has been suggested for the production of cresols by the oxidation of toluic acids. y -Cresol would be formed by the oxidation of either ortho or para toluic acids a mixture of 0- and -cresols would be produced from y -toluic acid (6). A process involving the vapor-phase catalytic oxidation of benzoic acid to phenol has been proposed, but no plants have ever been built utilizing this technology (27). 

The production of hydroxyl radicals was also shown by the oxidation of benzoic acid, a specific scavenger, with stimulated human granulocytes and by the formation... 

The 1,2-oxides of benzoic acids are also of interest as possible intermediates in the ortho hydroxylation and oxidative decarboxylation of aromatic acids. Ultraviolet studies indicate that benzene oxide 218 predominantly exists as its... 

The toluene-benzoic acid process involves three chemical reactions (1) oxidation of toluene to form benzoic acid, (2) oxidation of benzoic acid to form phenyl benzoate, and (3) hydrolysis of phenyl benzoate to form phenol. 

Chou S, Huang C. Applications of supported iron oxyhydroxide catalyst in oxidation of benzoic acid by hydrogen peroxide. Chemosphere 1999 38 2719-2731. 

MontUla, F., Michaud, P.-A., MoraUon, E., Vazquez, J.L. and ComnineUis, Ch. (2001) Electrochemical oxidation of benzoic acid on boron doped diamond electrodes. Portug. Electrochim. Acta 19, 221-226. 

Louhichi, B., Bensalash, N. and Gadri, A. (2006) Electrochemical oxidation of benzoic acid derivatives on boron doped diamond Voltammetric study and galvanostatic electrolyses, Chem. Eng. Technol. 29, 944-950... 

Dainton and Tordoff (9) showed that in the case of acrylamide Fe+ OH is a significant terminator. I am not, however, convinced of the validity of their suggested extension of this mechanism to other vinyl monomers, and similar generalizations, particularly in view of the fact that under otherwise identical conditions in experiments concerning the oxidation of benzoic acid (4) a doubled maximum yield of ferrous ion formation was determined by straightforward analytical methods, indicating that in the latter case, but not in the former, Fe+ OH must be considered as a terminator. This is quite independent of the quantitative estimate of the Fe+30H primary yield, which has become controversial. It is, however, feasible that Fe+ Br did not act as photoinitiator of the polymerization of methyl methacrylate or acrylonitrile because of eflficient termination with Fe+ Bir, which would not be unexpected. 

The oxidation of benzoic acid by divalent copper carried out by heating cupric benzoate to 210-260 C in high-boiling liquids furnishes 73-100% of salicylic acid [361]. 

Ni0-Fe203 catalysts were used for the vapor phase oxidation of benzoic acid to phenol. This reaction took place in a stream of air at 400°C. A catalyst having a Ni Fe atomic ratio of one gave phenol in 88% selectivity at 100% conversion. 0 ... 

Phenol is a material of major commercial importance. One of its earliest uses was as a disinfectant (carbolic acid). Earlier in the twentieth century, it became important as a feedstock for resins such as Bakelite , and in the latter part of the century it also became very important as a precursor for caprolactone and caprolactam and hence polyester and polyamide manufacture. The two major methods for phenol production nowadays are by the catalytic oxidation of benzoic acid and catalytic decomposition of cumene hydroperoxide (Scheme 4.55). 

Figure 16.6-1. Synthetic and preparative applications of oxidations of acids. A, B Oxidations of benzoic acid initiated by dihydroxylation (Sects. 16.6.4.2 and 16.6.4.3) C oxidative decarboxylation (Sect. 16.6.4.1) D,E energy coupling for the regeneration of coenzymes (Sects. 16.6.2, 16.6.3).

Significant effort was put into the oxidation of benzoic acid to cis,cis-muconic acid via a multi-step reaction catalyzed by whole microbial cells 21 24]. Cis,ris-muconic acid is used as raw material for the synthesis of resins and polymers (precursor of adipic acid). Furthermore, it is widely used as building block in the synthesis of pharmaceuticals and agrochemicals. 

Ogata, Y., K. Tomizawa, and Y. Yamashita. 1980. Photoinduced oxidation of benzoic acid with aqueous hydrogen peroxide. J. Chem. Soc. Perkin Trans. II 616-619. 

Liquid phase oxidation of benzoic acid and substituted benzoic acids (molten) to make phenols... 

Montilla F, Michaud PA, Morallon E, Varquez JL, Corrminellis C (2002) Electroehemical oxidation of benzoic acid at boron-doped rliamond electrodes. Electrochim Acta47(21) 3509-3513... 

The copper catalyzed oxidation of benzoic acid to phenol proceeds through benzoyl salicylic acid (I), which undergoes hydrolysis and decarboxylation ... 

MontiUa, F. et al. 2002. Electrochemical oxidation of benzoic acid at boron-doped diamond electrodes. Electrochimica Acta 47 3509-3513. 

For the oxirane and thiirane derivatives, different types of disconnections are preferred (Scheme 5.26). The epoxide in TM 5.10 can be disconnected to alkene and a source of oxygen. In the synthetic direction, convenient epoxidation agents are peracids, in particular meta-chloroperbenzoic acid (MCPBA). This reagent is produced on the industrial scale by chlorination and then oxidation of benzoic acid and, due to its selectivity and solubility in most organic solvents, is used for epoxidation of complex molecules even on the large scale [6]. 

Until 2005, DSM produced about 130 kt/a of phenol, used as a raw material to produce caprolactam from cyclohexanone. Phenol was produced by a copper-catalysed oxidation of benzoic acid. The raw material, benzoic acid, was produced in the same plant by the cobalt-catalysed oxidation of toluene, which also produced significant amounts of benzaldehyde (Fig. 16.19). 

Fraga-Dubreuil, J., Garcia-Serna, J., Garcia-Verdugo, E., et al. (2006). The catalytic oxidation of benzoic acid to phenol in high temperature water, J. Supercrit. Fluids, 39, pp. 220-227. 

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