JPS6259052B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing finely divided alkali hydroxide having a particle size of several μm to several μm.

Alkali hydroxide is used as an effective condensing agent in alkylation reactions of active methylene groups in organic solvents. It is preferable that the alkali hydroxide used in this way is dispersed in as fine particles as possible, but conventionally it has not been easy to disperse the alkali hydroxide in an organic solvent. On the other hand, when an attempt was made to forcefully disperse the material by heating and stirring, there was a problem in that alkali hydroxide adhered to the inner wall of the device.

The present inventors have conducted various studies in order to obtain an alkali hydroxide dispersion such as potassium hydroxide and sodium hydroxide dispersed in an organic solvent in an extremely fine state of several μm to several μm. It was discovered that the purpose could be achieved by heating and stirring in the presence of a certain kind of additive powder, and based on this finding, the present invention was accomplished.

Solid alkali hydroxide and inert organic solvent, general formula R': H, alkyl group m, n: A method for producing a granulated alkali hydroxide, which comprises heating and melting in the presence of alkylene glycol represented by an integer of 1 or more, stirring, and then lowering the temperature while stirring. .

Examples of the organic solvent used in the method of the present invention include halogenated hydrocarbons such as chloroform and carbon tetrachloride, aromatic hydrocarbons such as benzene, toluene, and xylene, and halogenated aromatic hydrocarbons such as chlorobenzene and chlorotoluene. Examples include solvents that are inert to hydrogen and other alkali hydroxides. Use of this organic solvent facilitates stirring, prevents moisture absorption of the alkali hydroxide, and promotes micronization of the alkali hydroxide. The amount of this solvent is not particularly limited as long as the amount allows sufficient stirring.

In addition, examples of the compound represented by the above general formula in the present invention include polymethylene glycol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, hexaethylene glycol, pentaethylene glycol, isopropylene glycol,
Examples include glycols such as polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, polypropylene glycol, 1,4-butanediol, and the like.

The amount of this compound added is usually 0.0001% by weight or more, preferably 0.001% by weight or more, based on the alkali hydroxide. These compounds may be used alone or in combination. In the present invention, these compounds are interposed between the alkali hydroxide particles to prevent reagglomeration, promote atomization of the alkali hydroxide, and prevent them from adhering to the inner wall of the apparatus.

In the method of the present invention, solid alkali hydroxide can be atomized by heating and stirring in the presence of such an organic solvent and the compound represented by the above general formula.

The heating and stirring at this time is preferably carried out at around the boiling point of the solvent, but when an organic solvent with a low boiling point is used, it is desirable to carry out the heating and stirring under pressure. A particularly preferred temperature range is 120° C. or higher at normal pressure, and this can be lowered further under pressure.

Further, stirring refers to stirring the organic solvent, the compound represented by the above general formula, and the alkali hydroxide, and there is no particular restriction on the method as long as the purpose is achieved. Examples include methods using stirring blades, homomixers, ultrasonic waves, or jet flow.

In this way, it is possible to obtain a dispersion in which fine particles of alkali hydroxide on the order of mμ or μ are dispersed. If the organic solvent is distilled off from this dispersion,
A finely divided alkali hydroxide is obtained, which can be reconstituted into the original dispersion by adding a solvent and stirring briefly. Depending on the use of the micronized alkali hydroxide, the solvent used in the intended application may be employed as the organic solvent of the present invention, and the dispersion of the micronized alkali hydroxide obtained by the method of the present invention may be used. It can also be used as is for the reaction.

According to the method of the present invention, solid alkali hydroxide can be easily atomized in a short time, which has been difficult in the past, and the atomized particles can be prevented from adhering to the inner wall of the apparatus, making it extremely efficient. The micronized particles thus obtained have a particle size of several microns to several microns, and when used as a condensing agent in alkylation reactions of active methylene groups, emulsification does not occur during operations after the reaction is completed; This is extremely effective from the standpoint of product separation and recovery.

Next, the present invention will be explained in more detail based on examples.

Example 1 In a 500 ml container made of SUS equipped with a stirring device with ordinary stirring blades, 52.08 g of solid potassium hydroxide (96% KOH), 200 ml of xylene, and 0.05 g of polypropylene glycol (0.1 weight relative to the amount of KOH) were placed. %), heated to 140°C, and stirred for 15 minutes at 2000 rpm by operating the stirring blade. Next, the temperature was lowered to room temperature while stirring to obtain a dispersion in which potassium hydroxide was dispersed in fine particles in xylene.

As a result of measuring the particle size of potassium hydroxide dispersed in xylene using a microscope, it was found to be 100 mμ to 10μ. Further, no potassium hydroxide was observed to adhere to the inner wall of the apparatus. A microscopic photograph of the dispersion liquid at this time is shown in FIG. The fine particles in the photo are dispersed particles of potassium hydroxide.

Example 2 A potassium hydroxide dispersion was prepared in the same manner as in Example 1 except that polyethylene glycol was used instead of polypropylene glycol as an additive. The thus obtained dispersed potassium hydroxide was fine particles with a particle size of 100 mμ to 10μ, similar to Example 1.

Example 3 A dispersion liquid was prepared in the same manner as in Example 1 using solid sodium hydroxide, and the same results as in Example 1 were obtained.

Comparative Example 1 Using the same apparatus as used in Example 1, 52.08 g of solid potassium hydroxide and 200 ml of xylene were charged, without heating, and using a stirring blade as was in Example 1.
It was stirred under the same conditions. The potassium hydroxide in the dispersion thus prepared was polygonal coarse particles. The micrograph is shown in Fig. 2. In the photo, the white outlines are coarse particles of potassium hydroxide.

Comparative Example 2 A dispersion of potassium hydroxide was prepared under heating at 140° C. in the same manner as in Example 1 except that polypropylene glycol was not used using the same stirring device as in Example 1.

In this case, the particle size of dispersed potassium hydroxide is 100 m
It was in the range of μ to several hundred μ, and potassium hydroxide was attached to the inner wall of the device.

Example 4 Add xylene to a 500 ml SUS separable flask equipped with a thermometer, dropping funnel, cooling tube, and stirrer.
200ml, polypropylene glycol (average molecular weight
1000) 0.05g and potassium hydroxide 50g (0.89mol) were heated to about 140℃ with stirring to melt the potassium hydroxide, and then gradually cooled to room temperature while stirring to form fine particles with a particle size of 100 μm or less. A xylene dispersion of potassium hydroxide was obtained. Next, 26 g (0.33 mol) of isopropylene chloride was added to this, and 34 g of 4-chlorophenylacetonitrile was added at room temperature while stirring.
After dropping 70 g (0.22 mol) over about 10 minutes,
The reaction was carried out at ~80°C for 50 minutes.

After the reaction was completed, the obtained reaction mixture was poured into 300ml of water, the organic layer was separated, and this was concentrated to remove xylene, and then distilled under reduced pressure to obtain bp104-106
40.4 g (yield 95%) of α-isopropyl-4-chlorophenylacetonitrile was obtained at a temperature of 1 mmHg.

For comparison, the reaction was carried out in the same manner as above except that 0.05 g of Tween-20 (trade name: polyoxyethylene sorbitan monolaurate) was used instead of polypropylene glycol. After the reaction was completed, the resulting reaction mixture was poured into 300ml of water.
When attempting to separate the organic layer, the liquid emulsified and separation was possible. For this reason, an emulsification breaking process became necessary.

[Brief explanation of the drawing]

FIG. 1 shows a microscopic photograph of an alkali hydroxide dispersion obtained by the method of the present invention, and FIG. 2 shows a microscopic photograph of an alkali hydroxide dispersion obtained by a conventional method.

Claims (1)

[Claims] 1. Solid alkali hydroxide with an inert organic solvent and the general formula In the presence of an alkylene glycol represented by (R′; H, alkyl group m, n; an integer of 1 or more), the alkali hydroxide atomized product is heated and molten, stirred, and then cooled while stirring. Production method.