Рідиннофазне окиснення 2-хлортолуену озоном до 2-хлорбензойної кислоти – напівпродукту для виробництва натрій диклофенаку

A. S. Bushuiev; A. H. Halstian; V. V. Kotova

doi:10.14739/2409-2932.2020.3.216168

Authors

A. S. Bushuiev Luhansk State Medical University, Rubizhne, Ukraine,
A. H. Halstian National Aviation University, Kyiv, Ukraine,
V. V. Kotova Luhansk State Medical University, Rubizhne, Ukraine,

DOI:

https://doi.org/10.14739/2409-2932.2020.3.216168

Keywords:

oxidation, 2-chlorotoluene, ozone, 2-chlorobenzoic acid, ozonolysis, catalyst, acetic acid

Abstract

2-Chlorobenzoic acid is used as an intermediate for diclofenac sodium production. In industry, it is obtained by oxidation of 2-chlorotoluene with potassium permanganate in an aqueous acidic medium. Due to the deficiency and cost of the oxidant as well as the formation of large amounts of toxic wastewater, the known method has no future. Therefore, an urgent task is to develop a new, low-waste synthesis of 2-chlorobenzoic acid using the available and ballastless oxidant – ozone. The kinetics and mechanism of the liquid-phase oxidation reaction of 2-chlorotoluene with ozone are studied. It was found that the oxidation of the substrate with ozone occurs mainly in the aromatic ring with the formation of aliphatic peroxide compounds. Increasing the temperature to 90 °C and introducing the catalyst – cobalt (II) acetate – into the system contributes to an increase of oxidation selectivity by the methyl group from 18.0% to 92.5 %. Among the aromatic products, 2-chlorobenzoic acid (88.0 %) and 2-chlorobenzaldehyde (4.2 %) are formed.

The aim of the work is to study the kinetics, the mechanism of the liquid-phase oxidation reaction of 2-chlorotoluene with ozone and to develop a new method of 2-chlorobenzoic acid synthesis basing on the research performed.

Materials and methods. Glacial acetic acid manufactured by Sigma, “Ch. P.” qualified; 2-chlorotoluene, 2-chlorobenzaldehyde, 2-chlorobenzoic acid manufactured by company "Acros organics" company, “Ch. P.” qualified; cobalt (II) acetate, “Ch. P. qualified” were used in the experiments. Studies of the reaction mass quantitative composition were performed by gas-liquid chromatography. 2-chlorobenzoic acid was determined with potentiometric titration. Ozone concentration at the reactor inlet and outlet was determined by the absorption spectrophotometric method in the range of 254–290 nm on a SF-46 spectrophotometer designed to measure the transmission coefficients of liquid and solid transparent substances in the spectral range from 190 nm to 1100 nm.

Results. The kinetics and mechanism of the liquid-phase oxidation reaction of 2-chlorotoluene with ozone have been studied. It was found that raising the temperature to 90°C and introducing a catalyst – cobalt (II) acetate – into the system results in an increase in the selectivity of oxidation by the methyl group from 18.0 % to 92.5 %. Among the aromatic products, 2-chlorobenzoic acid (88.0 %) and 2-chlorobenzaldehyde (4.2 %) are formed.

Conclusions. During the oxidation of 2-chlorotoluene with ozone in acetic acid, mainly aliphatic peroxide compounds are formed, and 2-chlorobenzoic acid is formed only with a yield of 16.5 %. Increasing the temperature to 90 °С and introducing cobalt (II) acetate into the catalyst system makes it possible to direct the process mainly to the methyl group with the formation of 88.0 % 2-chlorobenzoic acid.

References

Chen, Y. H., Chang, C. Y., Chen, C. C., & Chiu, C. Y. (2006). Kinetics of ozonation of 2-mercaptothiazoline in an electroplating solution combined with UV radiation. Industrial and Engineering Chemistry Research, 45(14), 4936-4943. https://doi.org/10.1021/ie060065w

Galstyan A. G., Skorokhod K. S., Galstyan T. M. (2020). Doslidzhennia kinetyky reaktsii katalitychnoho tsyklu v protsesi okysnennia etylbenzenu ozonom [Investigation of the kinetics of catalytic cycle reactions in the process of oxidation of ethylbenzene by ozone]. Pytannia khimii ta khimichnoi tekhnolohii, (4), 38-42. [in Ukrainian]. https://doi.org/10.32434/0321-4095-2020-131-4-38-42

Galstyan, G. A., Tyupalo, N. F., & Galstyan, A. G. (2009). Zhidkofaznoe kataliticheskoe okislenie aromaticheskikh soedinenii ozonom [Liquid-phase catalytic oxidation of aromatic compounds by ozone]. Lugansk: VNU. [in Russian].

Razumovskii, S. D., & Zaikov, G. E. (1974). Ozon i ego reaktsii s organicheskimi soedineniyami [Ozone and its reactions with organic compounds]. Moscow: Nauka. [in Russian].

Bailey P. S. (1978). Ozonation in organic chemistry. Vol. 1: Olefinic Compounds. Academik Press. https://doi.org/10.1016/B978-0-12-073101-5.X5001-X

Yakoby V. A. (1978). Ozonirovanie aromaticheskikh soedineniy. Reaktsionnaya sposobnost' organicheskikh soedinenii [Ozonation of aromatic compounds. Reactivity of organic compounds]. Trudy MKhTI im. D. I. Mendeleeva. Moscow. [in Russian].

Pan, H. L., Li, S. T., Shu, M. J., Ye, Y. W., Cui, Q. H., & Zhao, Z. X. (2018). p-Xylene catalytic oxidation to terephthalic acid by ozone. Scienceasia, 44(3), 212-217. https://doi.org/10.2306/scienceasia1513-1874.2018.44.212

Potapenko, E. V., & Andreev P. Y. (2012). Kataliticheskoe okislenie alkilbenzolov ozonom v uksusnoi kislote v prisutstvii silnykh kislot [Catalytic oxidation of alkylbenzenes with ozone in acetic acid in the presence of strong acids]. Neftekhimiya, 52(2), 132-137. [in Russian].

Pluzhnik, I. M., & Galstyan, G. A. (1999). Kinetika i mekhanizm kataliticheskoi reaktsii ozona s toluolom v uksusnoi kislote [Kinetics and mechanism of the catalytic reaction of ozone with toluene in acetic acid]. Neftekhimiya, 39(2), 120-123. [in Russian].

Razumovskyi, S. D., Halstian, H. A., & Tiupalo, M. F. (2000). Ozon ta yoho reaktsii z alifatychnymy spolukamy [Ozone and its reactions with aliphatic compounds]. Luhansk: SUDU. [in Ukrainian].

Emanuel, N. M., Denisov, E. T., & Maizus, Z. K. (1965). Tsepnye reaktsii okisleniya uglevodov v zhidkoi faze [Chain reactions of oxidation of carbohydrates in the liquid phase]. Moscow: Nauka. [in Russian].

Galstyan, A., Galstyan, G., & Timoshyna, L. (2018). Research of the process of liquid phase selective oxidation of 4-aminotoluene with ozone. Chemistry & Chemical Technology, 12(3), 341-345. https://doi.org/10.23939/chcht12.03.341

Zakharov I. V., & Galetii Yu. V. (1978). Mekhanizm i parametry okisleniya alkilaromaticheskikh uglevodorodov v prisutstvii ionov kobal'ta i broma [The mechanism and parameters of the oxidation of alkylaromatic hydrocarbons in the presence of cobalt and bromine ions]. Neftekhimiya, 18(4). 615-621. [in Russian].