Chemistry of carbon compounds – Miscellaneous organic carbon compounds – C-metal
Patent
1982-07-23
1984-10-16
Trousof, Natalie
Chemistry of carbon compounds
Miscellaneous organic carbon compounds
C-metal
562408, 562414, C07C 4604, C07C 51265
Patent
active
044773803
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a process of oxidizing reactive aromatics with molecular oxygen in the presence of a catalyst consisting of a cobalt compound in carboxylic acid and possibly with addition of a manganese and a bromine compound suitable as Co catalyst.
Reactive aromatics are those aromatic compounds which have one or more reactive carbon-hydrogen bonds. These may be either in methyl groups of a methyl-substituted aromatic, or in an aromatic nucleus. Examples of methyl-substituted reactive aromatics are toluene, xylenes, mono-alkyl naphthalenes such as 1-methyl naphthalene, or 2-methyl naphthalene, dimethyl naphthalenes such as 1,2-dimethyl naphthalene, 1,3-dimethyl naphthalene, 1,4-dimethyl naphthalene, 1,5-dimethyl naphthalene, 1,6-dimethyl naphthalene 1,7-dimethyl naphthalene, 1,8-dimethyl naphthalane, 2,3 dimethyl naphthalane, 2,6-dimethyl naphthalene or 2,7-dimethyl naphthalane, trimethyl naphthalenes or also methyl derivatives of higher annellated aromatics.
These products are oxidized to the respective carboxylic acids. Examples of reactive aromatics with reactive carbon-hydrogen bonds in an aromatic nucleus are anthracene as well as substituted anthracenes which do not have substituents oxidizable under the reaction conditions, such a halogen or nitro-anthracenes, or reactive multi-nucleus aromatics, such as fluorines or derivatives thereof. These compounds are oxidized to the respective quinones or ketones.
From DE-OS No. 2,107,357 a process is known for the oxidation of monomethyl or dimethyl naphthalenes with molecular oxygen. The oxidation takes place in aqueous, acetic acid solution using a catalyst which is composed of a cobalt, a manganese, and a bromine compound.
After completion of the reaction, a part of the acetic acid is distilled, the residue is mixed with much water, boiled out, and the mixture cooled, and the produced naphthalene carboxylic acid is precipitated and separated. The aqueous solution containing the catalyst is discarded. The process is labor-intensive and costly as to energy. Besides it is uneconomical to discard the catalyst after each reaction cycle.
The DE-OS No. 2,107,357 does indeed also indicate the possibility of recovering unreacted starting material, intermediate oxidation product and catalyst "by removal of water" and "recycling by subjecting the residual mother liquor to an oxidation treatment." However, considering the energy needed for evaporating the water, also this process step is not acceptable economically. Besides, it has been found that the catalyst solution thus re-used has lost almost its entire activity, so that a second reaction cycle with the same catalyst yields no appreciable conversion any more.
DE-AS No. 19 40 051 describes a process for the selective oxidation of anthracene fractions with molecular oxygen. The oxidation takes place in carboxylic solution using a catalyst composed of a cobalt, a manganese, and a bromine compound. No information is given about the processing of the catalyst system, but in view of its low price, the total loss is accepted.
The problem was, therefore, to find a simpler and more economical process for the oxidation of reactive aromatics which permits doing without the separation by distillation of relatively large quantities of solvent and using the catalyst solutions several times without an adverse loss of activity occurring.
The solution of the problem resides in a process for the oxidation of reactive aromatics with molecular oxygen in carboxylic acid solution in the presence of a catalyst consisting of a cobalt compound and possibly with addition of a manganese and a bromine compound suitable as Co catalyst, characterized in that after each reaction cycle the catalyst is reactivated by treatment with a strong oxidant and the water formed in the reaction is removed by distillation.
It has been found that the reason for the blocking of the catalyst system is that upon the oxidation of the aromatics due to secondary reactions or reactions of concomitants compounds are formed which bring about the formatio
REFERENCES:
patent: 3519684 (1970-07-01), Witt et al.
patent: 3856855 (1974-12-01), Yamashita et al.
Wiberg, ed., Oxidation in Organic Chemistry, Part A, p. 30, Academic Press, New York, 1965.
Chemical Abstracts, vol. 75, No. 1, Abstract No. 5576a, (1971), Robinson et al., "Liquid-Phase Oxidation of Condensed Aromatics."
Patents Abstracts of Japan, vol. 1, No. 157, p. 3503 (1977), Kokai, No. 52-101687, "Recovery of Catalyst."
Bohmer Bertram
Herzberg Roland
Knips Ulrich
Muserlian Charles A.
Rutgerswerke Aktiengesellschaft
Scott Patricia M.
Trousof Natalie
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