Method for refining monopotassium phosphate

Abstract

The invention relates to the field of pharmaceutical chemicals, and provides a refining method of monopotassium phosphate, which comprises the following steps: (1) adding water into monopotassium phosphate, and heating to 90-100 DEG C for dissolving; (2) filtering the solution obtained in the step (1), and cooling to 20-30 DEG C; and (3) adding a polar organic solvent, continuously cooling to 0-5 DEG C, filtering and drying to obtain a product. The method has the advantages that the polar organic solvent is added to assist crystallization, the yield is increased, the operation is simple, the step of concentrating and steaming water in the conventional process is omitted, the requirement on equipment is reduced, and the method is suitable for industrial production.

Description

Technical Field

[0001] The invention relates to the field of pharmaceutical chemicals, and in particular to a method for refining potassium dihydrogen phosphate. Background Art

[0002] Potassium dihydrogen phosphate is an inorganic salt that plays an important role in the medical field. For example, it is widely used in the treatment of hypokalemia; regulating acid-base balance to ensure that the body's pH remains within the normal physiological range; and contributing to cell metabolism and improving the body's disease resistance, thereby achieving the effect of enhancing immunity.

[0003] In order to obtain pharmaceutical grade potassium dihydrogen phosphate, potassium dihydrogen phosphate needs to be refined. The conventional refining process is to recrystallize with water, and the yield is only 60% to 70%. In order to improve the yield, it is often necessary to introduce concentrated water distillation or mother liquor reuse steps in the process operation. Such operations are cumbersome, and the material liquid after distillation is thick and difficult to discharge, requiring special crystallization equipment.

[0004] In order to solve the above problems, it is urgent to improve the existing refining process of potassium dihydrogen phosphate. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a method for refining potassium dihydrogen phosphate, which improves the yield by adding a polar organic solvent to assist crystallization, and is simple to operate, has low equipment requirements, and is suitable for industrial production.

[0006] The present invention adopts the following technical solutions to solve the above technical problems:

[0007] A method for refining potassium dihydrogen phosphate comprises the following steps:

[0008] (1) Add water to potassium dihydrogen phosphate and heat to 90-100°C to dissolve;

[0009] (2) filtering the solution obtained in step (1) and cooling the temperature to 20-30° C.;

[0010] (3) Add a polar organic solvent, continue to cool to 0-5°C, filter, and dry to obtain the product.

[0011] As one of the preferred embodiments of the present invention, in the step (1), the mass ratio of potassium dihydrogen phosphate to water is 1:(1.2-1.5).

[0012] As one of the preferred embodiments of the present invention, in step (3), the polar organic solvent is selected from one of ethanol, isopropanol and acetone.

[0013] As one of the preferred embodiments of the present invention, in the step (3), the polar organic solvent is added in a dropwise manner, and the total amount is 0.2 to 1.0 times (by mass) the amount of the potassium dihydrogen phosphate.

[0014] As one of the preferred embodiments of the present invention, in step (2), the solution is filtered and cooled before crystallization begins; in step (3), a polar organic solvent is used to assist crystallization, and after further cooling, filtering and drying, the final target product - refined potassium dihydrogen phosphate - is obtained.

[0015] As one of the preferred embodiments of the present invention, the yield of the product is above 90%, and the highest is 98%.

[0016] The advantages of the present invention compared to the prior art are:

[0017] By adding a polar organic solvent to assist crystallization, the yield can be increased to as high as 98%. At the same time, the operation is simple, eliminating the steps of concentration and distillation of water in the current conventional process, reducing the requirements for equipment, and being suitable for industrial production. DETAILED DESCRIPTION

[0018] The embodiments of the present invention are described in detail below. The embodiments are implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operation processes are given, but the protection scope of the present invention is not limited to the following embodiments. At the same time, the raw materials, reagents, equipment and experimental methods used in the following embodiments are conventional raw materials, reagents, equipment and methods in the art unless otherwise specified, and will not be repeated.

[0019] Example 1

[0020] A method for refining potassium dihydrogen phosphate of the present embodiment:

[0021] Add 1.0 kg of potassium dihydrogen phosphate and 1.5 kg of purified water to a 2L reaction bottle, heat to 90°C to dissolve. After filtering, cool to 20°C and start crystallization. At this time, add 1000 ml of ethanol to assist crystallization. Stir for 30 minutes after addition, continue to cool to 0°C, filter, and dry to obtain the product with a yield of 98%.

[0022] Example 2

[0023] A method for refining potassium dihydrogen phosphate of the present embodiment:

[0024] Add 1.0 kg of potassium dihydrogen phosphate and 1.4 kg of purified water to a 2L reaction bottle, heat to 95°C to dissolve. After filtering, cool to 25°C and start crystallization. At this time, add 400 ml of ethanol to assist crystallization. Stir for 30 minutes after addition, continue to cool to 4°C, filter, and dry to obtain the product with a yield of 95%.

[0025] Example 3

[0026] A method for refining potassium dihydrogen phosphate of the present embodiment:

[0027] Add 1.0 kg of potassium dihydrogen phosphate and 1.4 kg of purified water to a 2L reaction bottle, heat to 95°C to dissolve. After filtering, cool to 25°C and start crystallization. At this time, add 500 ml of acetone to assist crystallization. Stir for 30 minutes after addition, continue to cool to 4°C, filter, and dry to obtain the product with a yield of 96%.

[0028] Example 4

[0029] A method for refining potassium dihydrogen phosphate of the present embodiment:

[0030] Add 1.0 kg of potassium dihydrogen phosphate and 1.2 kg of purified water to a 2L reaction bottle, heat to 100°C to dissolve. After filtering, cool to 30°C and start crystallization. At this time, add 200 ml of isopropanol to assist crystallization. Stir for 30 minutes after addition, continue to cool to 5°C, filter, and dry to obtain the product with a yield of 90%.

[0031] The test results of the products (refined potassium dihydrogen phosphate) of the above embodiments are shown in Table 1.

[0032] Table 1 Test results of products in various examples

[0033]

[0034]

[0035]

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for refining potassium dihydrogen phosphate, characterized in that: The steps include: (1) Add water to potassium dihydrogen phosphate and heat to 90-100°C to dissolve; (2) filtering the solution obtained in step (1) and cooling the temperature to 20-30° C.; (3) Add a polar organic solvent, continue to cool to 0-5°C, filter, and dry to obtain the product.

2. The method for refining potassium dihydrogen phosphate according to claim 1, characterized in that: In the step (1), the mass ratio of potassium dihydrogen phosphate to water is 1:(1.2-1.5).

3. The method for refining potassium dihydrogen phosphate according to claim 1, characterized in that: In the step (3), the polar organic solvent is selected from ethanol, isopropanol and acetone.

4. The method for refining potassium dihydrogen phosphate according to claim 1, characterized in that: In the step (3), the polar organic solvent is added in a dropwise manner, and the total amount is 0.2 to 1.0 times that of the potassium dihydrogen phosphate.

5. The method for refining potassium dihydrogen phosphate according to claim 1, characterized in that: In the step (2), the solution is filtered and cooled before crystallization begins; in the step (3), a polar organic solvent is used to assist crystallization, and after further cooling, filtering and drying, the final target product - refined potassium dihydrogen phosphate - is obtained.

6. The method for purifying potassium dihydrogen phosphate according to any one of claims 1 to 5, characterized in that: The yield of the product is over 90%.

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