Organic compounds -- part of the class 532-570 series – Organic compounds – Unsubstituted hydrocarbyl chain between the ring and the -c-...
Reexamination Certificate
2001-09-27
2003-03-11
Kifle, Bruck (Department: 1624)
Organic compounds -- part of the class 532-570 series
Organic compounds
Unsubstituted hydrocarbyl chain between the ring and the -c-...
Reexamination Certificate
active
06531595
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method for producing &egr;-caprolactam from cyclohexanone oxime and, more specifically, a method for producing &egr;-caprolactam including the step of regenerating a zeolite or non-zeolitic material having lowered activity and a reactor for the method.
BACKGROUND OF THE INVENTION
&egr;-caprolactam is an important chemical raw material used as a basic material for the production of nylon and the like. In a classical method for producing &egr;-caprolactam, cyclohexanone oxime is rearranged to &egr;-caprolactam in liquid phase using concentrated sulfuric acid or fuming sulfuric acid as a catalyst (liquid phase Beckmann rearrangement reaction).
However, in the method using a liquid phase Beckmann rearrangement reaction, a large amount of ammonia is required for neutralizing the sulfuric acid, and consequently, a large amount of ammonium sulfate is produced as a by-product and significant costs arise due to the necessary treatment thereof.
Therefore, a method in which cyclohexanone oxime in the gas phase is Beckmann-rearranged using a solid catalyst (gas phase Beckmann rearrangement reaction) has been studied for a long time.
In the gas phase Beckmann rearrangement reaction, a cyclohexanone oxime vapor is reacted in the presence of a solid catalyst. The solid catalyst may be, for example, (1) a silica gel catalyst (U.S. Pat. No. 2,234,566), (2) a silica alumina catalyst (GB Patent No. 831,972), or (3) a zeolite catalyst (Journal of Catalysis, Vol. 6, p. 247, 1996, and U.S. Pat. Nos. 4,359,421 and 5,741,904).
Among them, crystalline zeolite catalysts having various compositions have been developed. This is because zeolite catalysts are known to have excellent catalyst life and selectivity to &egr;-caprolactam as compared with silica-based catalysts and the like.
In the gas phase Beckmann rearrangement reaction, deposits are generated on the surface of the catalyst during the reaction, and as a result, the activity of the catalyst is gradually lowered. In order to regenerate the deactivated catalyst, the catalyst is burned under an oxygen-containing gas at a high temperature.
In the case of burning the catalyst with oxygen, however, a significant heat release is caused by oxidation, whereby the temperature of catalyst rises. Furthermore, when deposits such as carbonaceous components (i.e. so-called coke) present on the catalyst are oxidized, water is produced which adversely influences the catalyst itself.
SUMMARY OF THE INVENTION
One object of the present invention is to provide a method for producing &egr;-caprolactam by a catalyst regeneration method capable of suppressing the deterioration of the catalyst.
This object and other objectives are achieved by the present invention which provides a method for producing &egr;-caprolactam from cyclohexanone oxime by using a zeolite or non-zeolitic material as a catalyst under gas phase reaction conditions. The method includes a reaction step for converting cyclohexanone oxime into E -caprolactam in the presence of the zeolite or non-zeolitic material, and a regeneration step of treating the zeolite or non-zeolitic material with a non-oxidizing gas at a temperature of from about 100° C. to about 600° C.
Also, the present invention provides a reactor charged with a zeolite or non-zeolitic material and having a reaction zone in which the zeolite or non-zeolitic material is utilized as a catalyst. A regeneration zone is also provided for the zeolite or non-zeolitic material, and a means for circulating the zeolite or non-zeolitic material between the reaction zone and the regeneration zone.
REFERENCES:
patent: 6071844 (2000-06-01), Hoelderich et al.
patent: 19608660 (1996-11-01), None
patent: 100 10 189 (2000-09-01), None
patent: 1028108 (2000-08-01), None
patent: 695 319 (1953-08-01), None
Albers et al., Journal of Castalysis, 176, 561-568 (1998).*
Ullmann's Encyclopedia of Industrial Chemistry, vol. B4, Part B, pp. 239-274.
Dahlhoff et al, American Chemical Society, Division of Enviromental Chemistry Reprints of Extended Abstracts, vol. 40 (1), pp. 177-179 Mar. (2000).
Takahashi et al, Stud. Surf. Sci. Catal, 97, pp. 431-436 (1995).
Dahlhoff Gerd
Hölderich Wolfgang F.
Ichihashi Hiroshi
Sugita Keisuke
Kifle Bruck
Sumitomo Chemical Company Limited
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