2-neopentylanthraquinone, processes for its preparation and meth

Details 2-neopentylanthraquinone, processes for its preparation and meth 2-neopentylanthraquinone, processes for its preparation and meth

1989-05-23

1992-04-21

Ivy, C. Warren

Organic compounds -- part of the class 532-570 series

Organic compounds

Polycyclo ring system containing anthracene configured ring...

C07C 5018

Patent

active

051070049

DESCRIPTION:

BRIEF SUMMARY
The present invention relates to the novel compound 2-neopentylanthraquinone of the formula ##STR1##
The present invention furthermore relates to the preparation of 2-neopentylanthraquinone by Friedel-Crafts acylation of neopentylglycol with phthalic anhydride and subsequent cyclization of the resulting 2-(4-neopentylbenzoyl)-benzoic acid in the presence of a strong, anhydrous acid.
The present invention also relates to the use of 2-neopentylanthraquinone as a catalyst in the preparation of hydrogen peroxide.
The industrially most important process for the preparation of hydrogen peroxide is the anthraquinone process. For this process, 2-alkylanthraquinones are required as catalysts.
In the process, which is carried out as a cyclic process, the dissolved 2-alkylanthraquinone is hydrogenated catalytically to the 2-alkylanthra hydroquinone, which, after removal of the hydrogenation catalyst, is oxidized back to the 2-alkylanthraquinone with oxygen. In this second step, hydrogen peroxide is formed and it is extracted from the reaction solution with water. The 2-alkylanthraquinone formed again is recycled into the recirculation. The process is described in more detail in, for example, Ullmann, Vol. 17, page 691 et seq., (4th Edition, Weinheim, New York, 1979).
The patent literature proposes various 2-alkylanthraquinones as catalysts in this process, for example 2-methyl-, 2-ethyl-, and 2-propylanthraquinone (U.S. Pat. No. 2,158,525), 2-isopropyl-, 2-sec-butyl- and 2-tert-butylanthraquinone (U.S. Pat. No. 2,935,381) and 2-amylanthraquinone (German Published Application DAS 1,112,051 and U.S. Pat. No. 3,041,143).
2-Amylanthraquinone is a mixture of roughly equal amounts of 2-tert-pentylanthraquinone and 2-(3-methylbut-2-yl)-anthraquinone. This mixture results from the first stage of the anthraquinone synthesis, ie. the Friedel-Crafts acylation of tert-pentylbenzene with phthalic anhydride, in which about half the tert-pentyl groups are isomerized to sec-pentyl groups.
2-Amylanthraquinone mixtures having a high content of tert-amylanthraquinone have proven particularly advantageous for the preparation of hydrogen peroxide (German Laid-Open Application DOS 2,013,299).
Although the isomerization of the tert-amyl group under the synthesis conditions can be partially suppressed, additional measures are required for this purpose (German Patent 2,720,294). Some of these additional measures require expensive technical apparatuses and give unsatisfactory yields.
High stability of the 2-alkylanthraquinone is important with regard to a long life of the 2-alkylanthraquinone/2-alkylanthrahydroquinone system. Furthermore, high solubility of the 2-alkylanthraquinone/2-alkylanthrahydroquinone system in the solvent systems used in the H.sub.2 O.sub.2 preparation is advantageous for a good space-time yield of the hydrogen peroxide process.
However, the amylanthraquinone mixtures have the disadvantage that only the tert-amyl compound has good stability whereas 2-sec-isoamylanthraquinone undergoes oxidation under the reaction conditions of the H.sub.2 O.sub.2 synthesis.
It is an object of the present invention to provide a catalyst for the hydrogen peroxide synthesis, which catalyst has high solubility in the quinone and hydroquinone forms in the reaction solution, has good stability under the conditions of the H.sub.2 O.sub.2 synthesis and furthermore can be prepared in a simple and economical manner.
We have found that this object is achieved by the novel compound 2-neopentylanthraquinone of the formula ##STR2## Furthermore, we have found a process for the preparation of 2-neopentylanthraquinone, wherein neopentylbenzene is acylated with phthalic anhydride by a Friedel-Crafts reaction to give 2-(4-neopentylbenzoyl)-benzoic acid and the latter is cyclized in the presence of a strong anhydrous acid to give 2-neopentylanthraquinone. We have also found that 2-neopentylanthraquinone is a catalyst for the preparation of hydrogen peroxide.
2-Neopentylanthraquinone is obtained from neopentylbenzene and phthalic anhydride in good yields w

REFERENCES:
patent: 3038786 (1962-06-01), Hiratsaka et al.
patent: 3923967 (1975-12-01), Kirchner et al.
patent: 4087458 (1978-05-01), Emori et al.
patent: 4853481 (1989-08-01), Henkelmann et al.
patent: 4895984 (1990-01-01), Eggersdorfer et al.
J. Chme. Soc. (C) 18 (1969), 2505-2506.

Affiliated with

Also associated with

Rating

2-neopentylanthraquinone, processes for its preparation and meth does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with 2-neopentylanthraquinone, processes for its preparation and meth, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and 2-neopentylanthraquinone, processes for its preparation and meth will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1588001