Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Patent
1988-11-23
1990-04-03
Reamer, James H.
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
568311, 585468, C07C 4528
Patent
active
049142429
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
This invention relates to a process for preparing 3-ethylbenzophenone. More particularly, this invention relates to a method to produce 3-ethylbenzophenone represented by the following formula (I) which comprises oxidizing a heavy oil fraction produced as a by-product in the preparation of ethylbenzene using ZSM-5 type synthetic zeolite catalyst, without splitting carbon-to-carbon bonds, said 3-ethylbenzophenone is a key starting material for synthesis of medicines and perfumes. ##STR1##
2. Background Art
The following method, for example, is known as the process for preparing 3-ethylbenzophenone.
That is, 3-ethylbenzophenone is obtained by Friedel-Crafts alkylation using benzophenone and diethyl sulfate in the presence of aluminum chloride (Spanish Patent No. 452500). According to this Spanish Patent, ketoprofen (trade name) as a medicine such as anti-inflammatory agent is synthesized. In this method, in spite of the use of highly pure starting materials, the refining is difficult because many kinds of by-products are formed, in addition, its yield is low.
Furthermore, it is proposed to produce 3-ethylbenzophenone by oxidizing the heavy by-product oil which is obtained from the alkylation of benzene with ethylene using aluminum chloride as an alkylation catalyst. However, it is necessary to carry out intensive oxidation with aqueous nitric acid, which is accompanied by the splitting of carbon-to-carbon bonds because the alkylation catalyst is aluminum chloride and therefore the composition of the by-product oil is different from that of the present invention. On account of the intensive oxidation, the yield of the aimed product is low and also it involves a danger of the generation of much explosive nitro compound.
Accordingly, the object of the present invention is to provide a method for synthesizing highly pure 3-ethylbenzophenone inexpensively.
DISCLOSURE OF INVENTION
The present invention relates to a process for inexpensively preparing highly pure 3-ethylbenzophenone.
In short, the process for producing highly pure 3-ethylbenzophenone comprises the step of oxidizing a starting material of a fraction containing (3-ethylphenyl)phenylmethane which is by-produced in the process to prepare ethylbenzene by reacting benzene with ethylene, without splitting carbon-to-carbon bonds.
In the following, the preparation method will be described in more detail.
(Alkylation)
In the preparation of ethylbenzene, benzene is alkylated with ethylene in the presence of an alkylation catalyst to obtain an alkylation product mainly containing unreacted benzene, ethylbenzene, polyethylbenzene and heavier products. This alkylation can be carried out by well known liquid phase alkylation method or gas phase alkylation method. The molar ratio of benzene to ethylene to be used may be about 25:1 to 1:5, preferably about 10:1 to 1:1.
The reaction is generally carried out in gas phase. For example, in the gas phase reaction, starting materials for alkylation are reacted by passing them through ZSM-5 type catalyst at a temperature in the range of about 250.degree. to 650.degree. C., preferably about 300.degree. to 550.degree. C. and under a pressure in the range of atmospheric pressure to 100 kg/cm.sup.2, preferably atmospheric pressure to 70 kg/cm.sup.2 and at a space velocity of WHSV in the range of 1 to 500, preferably 1 to 300.
As the result of such alkylation, alkylation products of unreacted benzene, ethylbenzene, polyethylbenzene and heavier products are obtained. If desired, the catalyst is previously removed.
The by-product oil is obtained by removing unreacted benzene, ethylbenzene and at least a part of polyethylbenzene form the alkylation products obtained as the above.
The synthetic zeolite catalyst used in the present invention is crystalline synthetic aluminosilicate zeolite of 20 or higher in molar ratio of SiO.sub.2 /Al.sub.2 O.sub.3 and the inlets of main pores thereof are composed of ten-membered oxygen rings. Such a zeolite is exemplified by ZSM-5 type synthetic zeolites hav
REFERENCES:
patent: 3038940 (1962-06-01), Serres et al.
patent: 3642906 (1972-02-01), Kahn
patent: 4731483 (1988-03-01), Shimizu et al.
patent: 4734528 (1988-03-01), Shimizu et al.
Olah et al, J.A.C.S., vol. 84, pp. 1688-1695 (1962).
Arai Yutaka
Matsumura Yasuo
Shimizu Isoo
Nippon Petrochemicals Company Limited
Reamer James H.
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