JPS62143822A - Novel solidification method for caustic soda - Google Patents

Abstract

PURPOSE:To solidify NaOH at a low temperature with saved energy in a relatively simple process, by heat-treating a complex in which a high-boiling alcohol incorporates NaOH and water under reduced pressure, removing the water and further removing the alcohol with an organic solvent. CONSTITUTION:An alcohol having >=160 deg.C boiling point, e.g. n-decanol, n- dodecanol, cyclohexanol, etc., is brought into contact with an aqueous solution of NaOH in a high concentration, preferably 45-60wt% to form an alcoholic caustic soda incorporation complex in which the NaOH and water are incorporated. The complex is then heat-treated under reduced pressure (normally heated at about 50-150 deg.C under 1-50mmHg reduced pressure for several minutes - several hours) and the alcohol is extracted with an organic solvent, e.g. acetone, etc., to obtain the aimed solid NaOH. The NaOH can be solidified with saved energy and without requiring the use of a high-class material for an apparatus in a low-temperature process as compared with a conventional boiling down process.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for solidifying caustic soda. More specifically, it relates to a method for solidifying caustic soda by subjecting an alcohol-based caustic soda uptake complex obtained by contacting an alcohol with a boiling point of 1600 or more with an aqueous caustic soda solution to a reduced pressure heat treatment, and then extracting the alcohol with an organic solvent. .

(Prior Art) Caustic soda, which is important in the chemical industry, is generally produced #1 by electrolysis of the corresponding common salt. However, what is obtained at a manufacturing plant using conventional methods is an aqueous solution with a high dIk degree, and this is normally transported as is to the destination for use. Because of its potash nature, it poses important problems in terms of pollution prevention, such as the risk of accidents. Moreover, this means that more than 50% of the water is being conveyed at full width, which is economically disadvantageous.

This is because the conventional method for solidifying caustic soda is an inefficient and energy-intensive process in which 50 liters of caustic soda is boiled in batches in a heavy oil-fired kettle. Furthermore, high concentration caustic soda T-350 ~
Since it is handled at temperatures as high as 400C, there are disadvantages such as the need to use expensive materials for the equipment.

(Problems to be Solved by the Invention) In the above-mentioned caustic soda industry, solid caustic soda is produced in a relatively simple process.

If it can be obtained at low temperatures and in an energy-saving manner, it will be extremely easy to handle and transport caustic soda as a basic industrial chemical, and it will have great industrial significance.

(Means and effects for solving the problem) The present inventor has conducted intensive research into the solidification of caustic soda, with the aim of improving the conventional solidification technology for caustic soda that requires high temperatures and an enormous amount of energy. As a result, solid caustic soda can be obtained by first removing water by heat treatment under reduced pressure from a complex in which an alcohol with a boiling point of 160C or higher incorporates caustic soda and water, and then removing glycol with an organic solvent. This led to the present invention. That is, according to the present invention, an alcohol having a boiling point of 160C or more is brought into contact with a caustic soda water bath to form an alcohol-based caustic soda-incorporating complex comprising caustic soda, water, and gold, and then the complex is directly subjected to a heat treatment under reduced pressure. Then,
A method for solidifying caustic soda is provided, which comprises extracting alcohol with an organic solvent to obtain solid caustic soda.

As mentioned above, the compound that incorporates caustic soda in the present invention is an alcohol with a boiling point of 160C or higher, and specifically, n-hebutanol, n-octanol, 2-octanol, n-decanol, n-dodecanol, cyclo Examples include hexanol. Among these, n-octanol, n-decanol, n-dodecanol, and cyclohexanol are preferred.

The concentration of the caustic soda aqueous solution used in the present invention is 45 to 6
0% by weight is preferred. Usually, industrially, caustic soda is produced at a concentration of about 50% by weight, but if a concentration of 50% or more by weight is required for the caustic soda used in the present invention, conventional caustic soda This evaporator is used for industrial purposes and can be efficiently concentrated. The ratio of alcohol to caustic soda aqueous solution varies depending on the type of alcohol, but is generally 10 to t2a:ffi! per 100 parts of caustic soda aqueous solution. :%.

There are no particular restrictions on the method of bringing caustic soda into contact with alcohol, but generally a high-torque mixer, kneader 1 kneader, etc. can be used. The reaction temperature is not critical and the reaction can be easily carried out at room temperature; however, when using an alcohol that is solid at room temperature, the reaction is carried out by heating the reaction to a temperature above the melting point of the alcohol. The reaction time is also not critical and is about 1 to 300 minutes. The anti-wide pressure may be atmospheric pressure. By the above operation, 100 crystals with a slightly moist feel, which are a complex of alcohol incorporating caustic soda and water, can be obtained quantitatively based on the amount of the preparation.

This crystal can be directly subjected to reduced pressure heat treatment. The conditions for the reduced pressure heat treatment are generally under reduced pressure of 1 to 50+a string g, heating time of about 50 to 150 C, and for several minutes to several hours. By this reduced pressure heat treatment, the water in the plate complex crystals evaporates first, leaving alcohol and caustic soda behind. By treating this complex consisting of alcohol and caustic soda with an organic solvent and performing total alcohol extraction, the complex is easily decomposed into alcohol and caustic soda, and the alcohol is easily dissolved in the form of a solution dissolved in the organic solvent. Can be separated. In this way, the residue is obtained in the form of solid soda particles.

The organic solvent used is an organic solvent that dissolves alcohol but does not dissolve caustic soda, such as acetone,
Mention may be made of dihydrofuran, dioxane, ether, hexane, and the like.

When the uptake complex is treated with an all-organic solvent, solid caustic soda can generally be obtained as a residue of the extraction by applying a solvent extraction method using a Soxhlet extractor or a suitable modification thereof. In this case, the separated and recovered alcohol can be reused for the production of the alcoholic caustic soda uptake complex used in the present invention.

As described above, caustic soda can be obtained in solid form by subjecting the alcohol-based caustic soda-incorporating complex to a heat treatment under reduced pressure and then treating it with a solid bath medium.

(Effects of the Invention) As described above, according to the present invention, a caustic soda solidification method that uses a low-temperature process, does not require the use of high-grade materials in equipment, and is energy-saving, compared to the conventional caustic soda solidification method using the boiling method. It becomes possible.

Its industrial significance is great.

(Example) Example 1 48% NaOH 100f in a 1 ton beaker. Put f,
Add n-octanol 851 at room temperature (20G) and mix with a mixer. Immediately upon addition, the reaction product precipitates out as crystals. One minute after addition, the mixer was stopped and the mixture was left at room temperature for 3 hours. In this way, slightly moist crystals were quantitatively obtained. 20 tons of the above crystals were placed in a 500-cm flask and subjected to reduced-pressure heat treatment at 120 C under a reduced pressure of 5° Hg for 1 hour. Next, the crystals were subjected to a Soxhlet extractor, and 200 mj'i of tetrahydrofuran was used as the organic solvent. Extracted for 1 hour. The thus obtained solid was heated in a caustic powder of 1R at 100C for about 1 hour to evaporate the adhering tetrahydrofuran.
5.12 solid caustic soda with a purity of 98.2% was obtained.

Example 2 Amount of caustic soda aqueous solution used, A degree and operation, except for using 65 M'i of n-decanol as the alcohol Example 1
In the same manner as above, solid caustic soda 5.7 with a purity of 97.8%
Friend who got 2.

Example 5 Solid caustic soda 4 with a purity of 9881% was prepared in the same manner as in Example 1 except that 100 tons of cyclohexanol was used as the alcohol.
．． I got 79f.

Example 4 Solid caustic soda with a purity of 97.6 was prepared in the same manner as in Example 1 except that 767 ft of n-dodecanol was used as the alcohol and the alcohol and aqueous caustic soda were mixed at 500 ft.
Obtained 49 f.

Comparison Example 1 48 * Put NaOH20t f into a 500- flask.

It was subjected to a vacuum heat treatment at 120C under a reduced pressure of 51)1aHg for 1 hour, and then extracted with tetrahydrofuran in the same manner as in Example 1 to obtain pre-prepared caustic soda 9.82 with a purity of 92.596.

Claims (2)

[Claims] (1) An alcohol with a boiling point of 160°C or higher is brought into contact with a highly concentrated aqueous solution of caustic soda to form an alcohol-based caustic soda uptake complex that incorporates caustic soda and water, and then the complex is subjected to a heat treatment under reduced pressure, and then ,
A method for solidifying caustic soda, which is characterized by extracting alcohol with an organic solvent and obtaining solid caustic soda. (2) The method for solidifying caustic soda according to claim 1, wherein the alcohol is an alcohol selected from the group consisting of cyclohexanol, n-octanol, n-decanol, and n-dodecanol.