Chemistry of inorganic compounds – Oxygen or compound thereof – Peroxide
Reexamination Certificate
1999-06-16
2001-08-14
Langel, Wayne (Department: 1754)
Chemistry of inorganic compounds
Oxygen or compound thereof
Peroxide
C205S432000, C556S001000, C556S138000
Reexamination Certificate
active
06274114
ABSTRACT:
BACKGROUND OF THE INVENTION
(i) Field of the Invention
The present patent application relates to a novel process for preparing hydrogen peroxide.
(ii) Description of the Related Art
The process most commonly used at the present time is a chemical process based on the oxidation of anthraquinone (Walton J. H., J. Am. Chem. Soc. (1932), 54, 3228; Filson G. W. et al., U.S. Pat. No. 2,059,569), which is commonly referred to as the “AO process”. This synthesis is performed according to the following reaction scheme:
The solution of alkyl anthraquinone, generally 2-ethyl anthraquinone, is hydrogenated in the presence of a catalyst (Pd on Al
2
O
3
), in a water-immiscible organic solvent. The hydroquinone obtained is then oxidized by atmospheric dioxygen into a mixture of hydroxy hydroperoxides which are decomposed into hydrogen peroxide and the starting alkyl anthraquinone, which is recycled. The hydrogen peroxide formed is separated from the organic phase by extraction with water, it being possible for the H
2
O
2
concentration to be up to 47% by weight; the aqueous solution is concentrated by distillation, in order to obtain the various commercial solutions. The main drawbacks of this method are associated with its hazards in the regeneration of the solution and the high running and maintenance costs of the process. Attempts have been made to replace the catalytic hydrogenation of anthraquinone with a chemical reduction on a sodium amalgam (Lynn S. et al., GB 1,154,096 and U.S. Pat. No. 3,351,104) or more recently by an electrochemical reduction (Keita B. et al., J. Electroanal. Chem. 1983, 145, 431-437; Schmidlin-Houissoud, A. Thesis from the University of Geneva 1997). However, none of these methods is industrially satisfactory.
Methods for producing hydrogen peroxide electrochemically are also known. The first of these is based on the electrolysis of sulphuric acid (Meindinger A., Ann. Chem. Pharm. Lieb. 1853, 88, 57; Bunsen R. W., Pogg. Ann. 1854, 91 621; Berthelot, M. C. R. 1878, 86, 71). Another method is based on the reduction of dioxygen with two electrons (Pascal P., in Nouveau traité de Chimie Minérale [Novel Treaty on Inorganic Chemistry]; Masson and Co.: 1960; Vol. Book XIII, 469-596; Tarasevich M. et al., in Comprehensive Treatise of Electrochemistry; Plenum Press: New York, 1983; Vol. 7; Divisek J. et al., J. Electroanal. Chem. 1975, 65, 603), either used in acidic medium (Damjanovic A. et al., J. Electrochem. Soc. 1967, 114, 466-472 and J. Electroanal. Chem. 1967, 15, 163-172; Genshaw M. A. et al., J. Electroanal. Chem. 1967, 15, 163-172; Taylor R. J. et al., J. Electroanal. Chem. 1975, 64, 85-94 and J. Electroanal. Chem. 1975, 64, 95-105; Otsuka K. et al., Electrochim. Acta 1990, 35, 319-322), or in basic medium (Paliteiro et al., J. Electroanal. Chem. 1987, 233, 147-159; Morcos I. et al., Electrochim. Acta 1970, 15, 953-975; Zhang Z. W. et al., Proc. Electrochem. Soc. 1984, 84, 158-178; Garten V. A. et al., Pure Appl. Chem. 1957, 7, 69-76; Kalu E. E. et al., J. Appl. Electrochem. 1990, 20, 932-940; Oloman C. et al., J. Appl. Electrochem. 1979, 9, 117-123; Stucki S. CH 4,455,203 1984; Kornienko G. V. et al., Russian J. Appl. Chem. 1996, 69, 229-231; Tatapudi P. et al., J. Electrochem. Soc. 1993, 140, 55-57; Taylor R. J. et al., J. Electroanal. Chem. 1975, 64, 63-84). Although in basic medium most promising results were obtained, the instability of hydrogen peroxide (Duke F. R. J. Phys. Chem. 1961, 65, 304) and the delicate nature of its extraction did not allow the results observed in the laboratory to be transposed to the industrial scale. Lastly, although the production of hydrogen peroxide by electrocatalysis appears to be of increasingly high-quality performance, the fragility of the various electrodes used remains, at the present time, a poorly controlled parameter (Deronzier A. J., Chim. Phys. Phys.-Chim. Biol. 1996, 93, 611-619; Vork F. T. A., Electrochim. Acta 1990, 35, 135; Degrand C. J., Electroanal. Chem. 1984, 169 259-268; Grangaard D. H., U.S. Pat. No. 3,454,477, 1969; Kang C. et al., J. Electroanal. Chem. 1996, 413, 165-174). Given the increasing number of applications of hydrogen peroxide, in particular in the electronics industry, it is advantageous to be able to produce hydrogen peroxide directly at its site of use. However, on account of the high operating costs, the installation of a manufacturing unit working according to the anthraquinone process is not viable for annual production of less than twenty thousand tonnes and it moreover presents several major drawbacks, such as the degradation of the reaction medium and the problems of safety.
SUMMARY OF THE INVENTION
The Applicant has thus sought another process for manufacturing hydrogen peroxide which can be carried out on site, with low maintenance costs and leading to a hydrogen peroxide solution of high purity. It has found that a chemical process for producing hydrogen peroxide, using organometallic complexes, solves the problems mentioned above. Accordingly, a subject of the invention is a process for preparing hydrogen peroxide, comprising the following steps:
a) a step of reduction of dioxygen in acidic medium with a hydrophobic organometallic complex, and
b) a step of separation of the oxidized organometallic complex resulting from step a) and of the hydrogen peroxide by liquid/liquid extraction.
Also provided is a plant for the production of hydrogen peroxide which can be used to practice the inventive methods.
REFERENCES:
patent: 2178640 (1939-11-01), Michalek et al.
patent: 2215856 (1940-09-01), Pfleiderer
patent: 5143710 (1992-09-01), Sawyer et al.
patent: 0 001 719 (1979-05-01), None
patent: 0 176 446 (1986-04-01), None
patent: 0 283 751 (1988-09-01), None
patent: 47304 (1982-03-01), None
Broeker Gregory
Guillard Roger
Ledon Henry
Royal Guy
Tabard Alain
Burns Doane Swecker & Mathis L.L.P.
L'Air Liquide, Societe Anonyme pour l'Etude et l'
Langel Wayne
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