JPH0380941A - Method for activating and regenerating aldol condensing catalyst - Google Patents

Abstract

PURPOSE:To activate or regenerate an aldol condensing catalyst within a short time by treating the aldol condensing catalyst with hot water having a specific range of temp. under pressure. CONSTITUTION:A water-insoluble or hardly water-soluble basic solid such as a basic compound containing alkaline earth metal such as magnesium hydroxide or calcium hydroxide is supported on a carrier to prepare an aldol condensing catalyst. This catalyst is brought into contact with hot water at 120-180 deg.C, pref., under pressure of about 2-10kg/cm<2> usually for about 4-20hr. By this method, the catalyst is activated and regenerated within a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for activating and regenerating a basic catalyst for aldol condensation.

A method for producing diacetone alcohol by aldol condensation of strained acetone is described, for example, in Japanese Patent Publication No. 61-16257.
This is already known as described in the publication No. Normally, continuous operation is performed.

As a catalyst for such aldol condensation, a basic solid catalyst is usually preferably used, for example,
Alkaline earth metals, solid catalysts made by supporting these metals on various carriers, basic ion exchange resins, and the like are used.

Here, in order for such a catalyst to have high activity, it is desirable that the solid surface of the catalyst be porous, and for this reason, conventionally, the catalyst is usually washed with hot water or hot water under normal pressure. Although the catalyst has been activated, it takes a long time to process and the level of activation is low.Similarly, catalysts with reduced activity are usually regenerated as described above.
being reused. However, when regeneration requires a long time as described above, production capacity is reduced, which in turn has a detrimental effect on the economics of producing diacetone alcohol.

Examples of activation and regeneration methods other than those mentioned above include:
No. 7-18731 describes a method of treating the catalyst with acetone containing a small amount of water.

The present invention has been made in order to solve the above-mentioned problems in the activation and regeneration of conventional basic catalysts for aldol condensation. The purpose is to provide a method of revitalization and regeneration that can.

The activation and regeneration method of the aldol condensation catalyst according to the present invention for reducing the amount of
Basic catalyst for aldol condensation under pressure
It is characterized by treatment with hot water at a temperature of 180°C.

In the present invention, in consideration of the industrial implementation of aldol condensation, water-insoluble or sparingly soluble catalysts are used because it is easy to separate the reaction product from the catalyst and to circulate and reuse the catalyst. It is preferable to use a basic solid catalyst of

Examples of such water-insoluble or sparingly soluble basic solid catalysts include alkaline earth catalysts such as magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, magnesium oxide, calcium oxide, strontium oxide, and barium oxide. Examples include basic compounds containing similar metals, catalysts formed by supporting these basic compounds containing alkaline earth metals on various carriers, basic ion exchange resins, and the like. In particular, the method of the present invention is advantageous for activating and regenerating alkaline earth metal-containing basic compounds and catalysts formed by supporting these alkaline earth metal-containing basic compounds on various carriers.

According to the invention, such a catalyst is heated under pressure to 120 to 180
The catalyst can be highly activated by contacting it with hot water at a temperature of .degree. The treatment temperature is preferably 1
The temperature is 40 to 180''C.The treatment pressure is not particularly limited as long as it exceeds normal pressure at which the catalyst can be steamed as described above.
Preferably it is 2 to 10 kg/c+fl, particularly preferably 3 to 10 kg/cd. In addition, the longer the processing time, the more the activity level increases.
Even if the treatment is carried out for an excessively long time, the activation level tends to be saturated, which is not preferable from an economic point of view. Therefore, the treatment time is usually 4 to 20 hours, preferably 8 to 20 hours.

In this manner, a highly activated or regenerated catalyst can be obtained by subjecting the catalyst to hydrothermal treatment at high temperature and pressure in a closed container, followed by cooling, washing with water, and washing with acetone.

As described above, according to the present invention, a basic solid catalyst for aldol condensation can be activated or regenerated to high activity in a short time by hot water treatment at high temperature and high pressure. can.

Although the present invention will be described below with reference to Examples, the present invention is not limited to these Examples in any way.

Examples 1 to 6 and Comparative Examples 1 to 4 Calcium hydroxide was sintered with a binder, pulverized, and made into granules. 20 g of a basic solid catalyst and 28.5 g of pure water were
The mixture was charged into a 00ml capacity SUS reactor and sealed. The reactor was heated by immersing it in an oil bath previously maintained at a predetermined temperature for a predetermined time. Thereafter, the reactor was cooled, and the catalyst was taken out and washed with water and acetone to prepare an activated catalyst.

10 g of the catalyst thus obtained and 100 g of acetone were charged into a 200 ml glass reactor equipped with a stirrer, and reacted for 1 hour at a stirring speed of 350 rpm+ and a reaction temperature of -5°C. The activity of the catalyst was evaluated by checking the diacetone alcohol concentration. The results are shown in Table 1 and Figure 1.

As is clear from these results, according to the present invention, a highly activated catalyst can be obtained by a short treatment time. The level of activation by hydrothermal treatment at 100° C. for 20 hours was increased according to the invention by 14 hours at 180° C. for 2 hours.
This can be achieved by treatment for 6 hours at 0°C.

Example 7 Using the catalyst described in Example 1, aldol condensation of acetone was carried out continuously. The reaction was carried out in a jacketed glass reaction vessel with a capacity of 80 ml, filled with 80 ml of the above catalyst, and using acetone at a constant concentration as a raw material in a fixed bed continuous flow system (downflow) at L HS V 3.0.

As a result, as in the previous example, a catalyst whose activity as evaluated by the diacetone alcohol concentration of the reaction solution was reduced to 6% by weight was heated at 140°C for 6 hours and at 180°C as described above.
The catalyst was regenerated by hydrothermal treatment at 0C for 4 hours.

Using these regenerated catalysts, aldol condensation of acetone was carried out under the same conditions as in the previous example, and the activities were 11.02% by weight and 11.40% by weight, respectively.

[Brief explanation of drawings]

Figure 1 shows the treatment temperature and time when a basic solid catalyst for aldol condensation is activated by hot water treatment at a predetermined temperature for a predetermined time, and is used to perform aldol condensation of acetone, and the temperature and time of the reaction solution. It is a graph showing the relationship between diacetone alcohol concentration and diacetone alcohol concentration.

Claims (1)

[Claims] (1) Basic catalyst for aldol condensation under pressure
A method for activating and regenerating an aldol condensation catalyst, which comprises treating with hot water at a temperature of 20 to 180°C.