Chemical apparatus and process disinfecting – deodorizing – preser – Chemical reactor – Including internal mixing or stirring means
Reexamination Certificate
2000-04-07
2002-09-24
Johnson, Jerry D. (Department: 1764)
Chemical apparatus and process disinfecting, deodorizing, preser
Chemical reactor
Including internal mixing or stirring means
C422S198000, C422S198000, C422S224000
Reexamination Certificate
active
06455016
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a reaction apparatus to be used in the production of an alkanolamine, a method for production of an alkanolamine using the apparatus, a reactor, a method for charging the reactor with a catalyst, and a method for start-up of the production of an alkanolamine.
More specifically, it relates to a reaction apparatus to be used in producing a dialkanolamine by the reaction of ammonia, a monoalkanolamine, and an alkylene oxide in the presence of a solid catalyst, a method for selectively producing the dialkanolamine using the reaction apparatus, a reactor to be used in the production of an alkanolamine, a method for charging the reactor with a catalyst, and a start-up method for safe and efficient production of an alkanolamine using an adiabatic reactor in the presence of a solid catalyst by adjusting the temperature and the concentration of the raw material components during the contact between the raw materials and the catalyst.
2. Description of the Related Art
As a commercial approach to the production of an alkanolamine by the amination of an alkylene oxide with ammonia, the method which produces ethanolamine by the reaction of ethylene oxide with aqua ammonia (ammonia concentration in the range of 20-40 wt. %) has been in vogue. Though this method forms three species of amine, i.e. monoethanolamine, diethanolamine, and triethanolamine, it is required to repress the formation of triethanolamine among other species of amine because the demand for triethanolamine is decreased. The reaction, therefore, is generally carried out with the molar ratio of ammonia and ethylene oxide set at a large ammonia excess in the approximate range of 3-5. In spite of the effort, the selectivity of triethanolamine is in the range of 10-20 wt. % or more and the selectivity of diethanolamine is not more than 40% by weight.
In an anhydrous system, substantially no reaction occurs between an alkylene oxide and ammonia. For the reaction of this nature, therefore, a catalyst is indispensable. Thus, homogeneous catalysts such as organic acids, inorganic acids, and ammonium salts have been proposed (Swedish Patent No. 158,167). These homogeneous catalysts are difficult to be separated from the reaction system and fail to manifest fully satisfactory performance.
As an embodiment of the immobilization of such a homogeneous acid catalyst, an ion-exchange resin having a sulfonate group immobilized on resin has been proposed (U.S. Pat. No. 3,697,598). Since this catalyst manifests relatively good activity and selectivity, it has been already practiced on a commercial scale. The ion-exchange resin, however, entails the problem of having a low maximum working temperature. The ion-exchange resins which are commercially available generally have rather low maximum working temperatures of 120° C. (“Ion Exchange—Introduction to Theory and Practice” translated jointly by Rokuro Kuroda and Masami Shibukawa, published by Maruzen Co., Ltd., 1981, page 34). When ammonia and ethylene oxide are subjected to a reaction at a lowered molar ratio, the temperature of the catalyst bed is eventually compelled by the heat of reaction to exceed the heat resistant temperature. When the catalyst is used under these temperature conditions for a long time, it entails the problem of inducing deterioration of the catalyst. It is, therefore, difficult to lower the molar ratio of ammonia and ethylene oxide to a level in the approximate range of 20-25. With a view to overcoming the drawback of poor high-temperature resistance of the ion-exchange resin, an inorganic catalyst excelling in thermal stability has been studied.
U.S. Pat. No. 4,438,281 discloses silica alumina in popular use manifests a good catalytic activity.
Industrial and Engineering Chemistry, Product Research and Development, 1986, Vol. 25, pp. 424-430 publishes a comparative study performed between ion-exchange resins and various kinds of zeolite catalysts, etc. Particularly, in terms of the selectivity to a monoalkanolamine, no other substances used in this study surpassed ion-exchange resins.
U.S. Pat. No. 4,939,301 discloses acid activated clay catalysts. Some of these catalysts have manifested high yields of monoethanolamine of not less than 60% by weight. Since no catalyst has manifested a fully satisfactory selectivity to a monoalkanolamine, the reaction of ammonia and ethylene oxide is carried out with the molar ratio of these reactants increased to not less than 20-30 times the stoichiometric level. This reaction, however, is hardly practicable because the cost of equipment for recovering ammonia for cyclic use is prohibitive.
With a view to solving these problems, EP 652 207 A proposes use of a catalyst having a rare earth element carried on a heat-resistant carrier to produce a monoalkanolamine with a high selectivity. Since this catalyst is aimed at producing a monoalkanolamine with a high degree of selectivity, it is still deficient to produce a dialkanolamine.
A catalyst having a high degree of selectivity for a dialkanolamine can be obtained by using a microporous material having an effective pore diameter in the range of 0.45 to 0.8 nm or a catalyst obtained by subjecting this microporous material to an ion-exchange treatment and/or a surface treatment.
When the dialkanolamine further obtained by the use of this catalyst with a still higher degree of selectivity, the amount of the dialkanolamine ought to be increased theoretically by separating the monoalkanolamine formed in advance and recycling part of the separated monoalkanolamine to the reaction system. Neither an apparatus nor a method available for this method has been specifically disclosed, this method has a problem yet to be solved for the purpose of production to practice.
It has been known to produce an alkanolamine by the reaction of liquid ammonia with an alkylene oxide as disclosed in for example U.S. Pat. No. 3,697,598 and EP 652 207 A.
This production, when carried out on a commercial scale, however, has the possibility of inducing a channeling of the reaction mixture in the catalyst bed or an outflow of fine catalyst particles from the reactor.
For the purpose of preventing this channeling in a relatively large reactor, it needs to use a special catalyst packing device or a reactor of a complicated shape as described for example in JP-A-10-66,858, JP-A-07-60,102, JP-A-05-285,367, and PETROTECH, Vol. 20, pp. 960-965.
In recent years, with a view to overcoming the problem of heat resistance due to the use of such an ion-exchange resin, the feasibility of using an inorganic catalyst which excels in thermal stability under adiabatic conditions has been studied. EP 652 207 A for example, discloses catalyst for the production of an alkalolamine, which are characterized by carrying a rare earth element on a heat resisitant inorganic carrier. Since this catalyst itself carries heat resistance unlike an ion-exchange resin, the reaction can be carried out at a temperature of 50-300° C., preferably of 80-200° C. By using such a heterogeneous catalyst excelling in heat resistance, it is possible to increase the ratio of the alkylene oxide, improve the productivity of the reaction, and repress the ratio of ammonia to a low level, and thereby miniaturizing the reactor. Further, since the reaction temperature can be maintained at a high level, the efficiency of the reaction can be improved. In addition, the adiabatic reaction has an advantage that, when the reaction starts once, it continues the reaction by heat generated and ensures the sufficient rise of temperature necessary for performing the reaction promptly.
When the reaction of ammonia with an alkylene oxide is effected with the heterogeneous catalyst excelling in heat resistance under the adiabatic conditions between the exterior and the reactor, the interior of the reactor assumes an unstable state for a short while after the start-up. When the heterogeneous catalyst excelling in heat resistance is used, the ethylene oxide concentration can be maintained at a rather hi
Doroshenk Alexa A.
Johnson Jerry D.
Nippon Shokubai Co. , Ltd.
LandOfFree
Reaction apparatus for production of alkanolamine does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Reaction apparatus for production of alkanolamine, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Reaction apparatus for production of alkanolamine will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2871847