Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2000-12-27
2001-10-09
Trinh, Ba K. (Department: 1625)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C549S534000, C549S537000
Reexamination Certificate
active
06300507
ABSTRACT:
TECHNICAL FIELD TO WHICH THE INVENTION BELONGS
This invention relates to a process of manufacturing ethylene oxide. More detailedly, the invention relates to a process of manufacturing ethylene oxide stably by catalytic vapor phase oxidation reaction.
1. Prior Art
It is widely and industrially carried out to manufacture ethylene oxide by vapor phase oxidation of ethylene in the presence of a silver catalyst. In this process, vapor phase oxidation of ethylene is continuously carried out by contacting an ethylene raw material gas with a silver-containing catalyst loaded into a reactor to partially oxidize the gas, recovering the ethylene oxide in the reaction gas, supplementing the reaction gas containing unreacted ethylene with fresh ethylene, etc. to adjust the gas composition, and then introducing the resulting mixed gas as an ethylene raw material gas into the reactor. In this process, for inhibiting formation of carbon dioxide due to complete combustion of ethylene, it has hitherto been carried out to add an organic halide such as ethylene dichloride (EDC) as a reaction inhibitor into the ethylene raw material gas. This organic halide is added as gas in a slight amount into the ethylene raw material gas.
2. Problems to be Solved by the Invention
However, there has been a problem in the conventional process where the organic halide is added as a gas that the process is insufficient for maintenance of the stability of the oxidation reaction itself and the ethylene oxide selectivity is not satisfyingly high.
Although the ethylene oxide selectivity in today's ethylene oxide manufacturing technology is already in a high level, an increase of the selectivity even if the degree is as small as a few % brings about a large economic effect in view of large production scale of ethylene oxide.
Thus, the object of the invention lies in providing a process of manufacturing ethylene oxide which makes it possible to manufacture ethylene oxide stably and in high selectivity.
3. Means for Solving the Problems
The present inventors have made researches into cause of the above problems, and have found that in the conventional process where a saturated gas formed by bubbling a gas such as ethylene or nitrogen into an organic halide liquid is added to the ethylene raw material gas, it is impossible to add the organic halide always at a constant amount to the ethylene raw material gas, which is a cause of the problems. The reason is that it happens, due to fluctuation of the flow rate and pressure of the ethylene raw material gas to which the organic halide is added, that the organic halide is added in a large amount at a time as a mist. Once the organic halide is added in a large amount at a time, control of the reaction gets very difficult and stable progress of the oxidation reaction gets impossible, for example the reaction being rapidly inhibited or sometimes the reaction being stopped. Moreover, it has also been found that if the addition amount of the organic halide is not constant, problems arise for example that the concentration of the organic halide in the ethylene raw material gas gets ununiform and the ethylene oxide selectivity lowers.
Thus, the present inventors have made vigorous researches into dispersing the organic halide uniformly into the ethylene raw material gas and making the concentration of the organic halide in the ethylene raw material gas substantially uniform, for example, by making the addition amount of the organic halide to the ethylene raw material gas constant.
As addition methods of the organic halide, besides the conventional method where it is added as a gas, the following methods are considered.
(1) Add the organic halide as an aqueous solution to the ethylene raw material gas.
(2) Add the organic halide as a solution in an organic solvent to the ethylene raw material gas.
(3) Add the organic halide itself as liquid to the ethylene raw material gas.
As a result of the present inventors' researches, the following things have been found on these methods (1), (2) and (3).
In the case of the method (1), since the organic halide generally has a low solubility in water and a large specific gravity, dissolution of the organic halide in water gets insufficient and sometimes the reaction gets to be a dangerous state by that the undissolved organic halide enters the reaction system. In the case of the method (2), sometimes, the organic solvent to be used has a bad influence on the oxidation reaction or spoils the quality of the product ethylene oxide.
On the other hand, in the case of the method (3), since, when the organic halide in a liquid state is sent in a pressurized state from its storage tank by a pump and introduced into the ethylene raw material gas, the pressure of the storage tank can, usually, be made lower than the process pressure (the pressure of the ethylene raw material gas), getting to be excessive addition intrinsically does not happen, and it is possible to add a constant amount of the organic halide to the ethylene raw material gas flow in faithful accordance with even fluctuation of the ethylene raw material gas flow.
The invention has been accomplished based on these findings.
Thus, according to the invention, in manufacturing ethylene oxide by catalytic vapor phase oxidation of ethylene in the presence of an organic halide as a reaction inhibitor, a process of manufacturing ethylene oxide comprising adding the organic halide as liquid into the ethylene raw material gas flow is provided.
REFERENCES:
patent: 2279469 (1942-04-01), Law et al.
patent: 2279470 (1942-04-01), Law et al.
Oka Yoshihisa
Takematsu Kenichi
Nippon Shukubai Co Ltd
Trinh Ba K.
LandOfFree
Process of manufacturing ethylene oxide does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process of manufacturing ethylene oxide, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process of manufacturing ethylene oxide will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2594108