Method for rectifying and purifying diethyl chlorophosphate crude product

Abstract

The invention relates to a rectification purification process of diethyl chlorophosphate, in particular to a rectification purification method of a diethyl chlorophosphate crude product. Comprising the following steps: (1) balancing a chromatographic column, (2) loading a sample, (3) eluting, (4) collecting, (5) washing impurities, (6) post-treating, combining the separated and prepared components, adding a 10% methanol-water mixed solution, uniformly shaking and standing for 10 minutes; then adding dichloromethane and ethanol extract liquor for rectification, oscillating by using an oscillator, then standing, retaining lower liquid, and then carrying out reduced pressure distillation to obtain purified diethyl chlorophosphate; impurities in the crude product are removed through reduced pressure distillation, rectification extraction, column chromatography and other methods, and the purity of the purified sample reaches 99.6% or above. Therefore, the preparation of the purity standard substance is facilitated.

Description

Technical Field

[0001] The invention relates to a diethyl chlorophosphate rectification and purification process, and in particular to a diethyl chlorophosphate crude product rectification and purification method. Background Art

[0002] Diethyl chlorophosphate is a colorless liquid with a pungent odor. It smokes when placed in humid air and reacts violently with water. It is a good phosphating agent that can convert phenols into aromatic hydrocarbons and aromatic amines, and promote the reduction of phenols and enols. It is usually prepared by chlorination of diethyl phosphite. Diethyl chlorophosphate is widely used in the preparation of pesticides and pharmaceutical intermediates. In addition, diethyl chlorophosphate is often used as a simulant of nerve agents in research to detect the performance of alarm instruments. The classic method for synthesizing diethyl chlorophosphate is a two-step synthesis: first, phosphorus trichloride and anhydrous ethanol undergo an exothermic reaction to generate diethyl phosphite, and then undergo a chlorination reaction to generate diethyl chlorophosphate. It can also be prepared directly by the chlorination reaction of diethyl phosphite.

[0003] Diethyl chlorophosphate is generally used for alarms of phosphorus-containing agents. Chemical agents or chemical agent simulants used for alarms require stable reagents to ensure the accuracy of the alarm threshold and thus protect the lives of personnel. If the content of impurities with properties similar to those of the alarmed substance is high during the alarm evaluation process, it may cause misjudgment of the alarm and affect its accurate measurement.

[0004] The synthesis process of diethyl chlorophosphate of each manufacturer is slightly different, resulting in slightly different types and contents of impurities in the synthesized products. Different impurities require different purification methods. For example, ethanol can be removed by ordinary distillation, but for substances with similar properties to diethyl chlorophosphate, ordinary distillation / rectification is not applicable. Therefore, in order to remove organic impurities in diethyl chlorophosphate as much as possible, it is necessary to study and design a distillation purification process. Summary of the invention

[0005] The invention provides a method for distilling and purifying crude diethyl chlorophosphate in order to solve the technical problem that the raw materials contain diethyl chlorophosphite, triester phosphate and the like, which have similar physical and chemical properties and boiling points to diethyl chlorophosphate, and high-purity products cannot be obtained by ordinary distillation and extraction.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for distilling and purifying crude diethyl chlorophosphate, characterized in that it comprises the following steps: (1) Column balance: Mobile phase A is water, and mobile phase B is methanol. After the column is connected, if the instrument is running well, flush the system with 5% methanol mobile phase at a flow rate of 150 mL min-1 for 30 min. (2) Loading: After equilibration, place pipe A in a measuring cylinder containing crude diethyl chlorophosphate and load the crude product through pump A at a rate of 130 mL min-1. After loading, stop the pump and replace it with water phase to flush pipe A at a rate of 100 mL min-1 for 20 seconds before stopping the pump. Finally, replace pipe A with mobile phase A. (3) Elution: After loading, start gradient elution, flush with 5% methanol mobile phase for 60 min, and then change to 100% methanol to flush the column for 30 min; (4) Collection: When the main peak appears in the analytical peak segment of the instrument, start segmented collection, collecting one tube every 3 minutes; (5) Impurity flushing: After collection, flush with 100% methanol until the instrument peaks disappear, which means the impurities have been completely flushed. Stop the pump and the early separation process is completed. (6) Post-treatment: Combine the separated components, add 10% methanol-water mixture, shake well and let stand for 10 min; then add dichloromethane and ethanol extract for distillation, shake with an oscillator and let stand, retain the liquid below, and then perform vacuum distillation to obtain purified diethyl chlorophosphate.

[0007] As a further limitation of the technical solution of the present invention, the volume ratio of the crude diethyl chlorophosphate in the measuring cylinder of step (2) to the 10% methanol-water mixture in step (6) is 5:3.

[0008] As a further limitation of the technical solution of the present invention, the volume ratio of dichloromethane to ethanol in the dichloromethane-ethanol extract in step (6) is 500:1.

[0009] As a further limitation of the technical solution of the present invention, in step (6), the oscillator is oscillated for 30 minutes and then allowed to stand for 2 to 3 hours.

[0010] As a further limitation of the technical solution of the present invention, the temperature of the reduced pressure distillation in step (6) is 80° C., the vacuum degree is -0.1 MPa, and the reduced pressure distillation time is 80 to 100 min.

[0011] As a further limitation of the technical solution of the present invention, the concentration of the purified diethyl chlorophosphate obtained in step (6) is above 99.6%.

[0012] Compared with the prior art, the present invention has the following beneficial effects: Since the candidate raw materials contain impurities such as diethyl chlorophosphite and triester phosphate, which have physical and chemical properties and boiling points similar to those of diethyl chlorophosphate, the purity can only reach about 95% after purification by traditional methods. The present invention removes impurities in the crude product through methods such as reduced pressure distillation, distillation extraction, column chromatography, etc., so that the purity of the purified sample reaches more than 99.6%.

[0013] The diethyl chlorophosphate standard substance with a concentration of more than 99.6% prepared by the present invention can be used for drawing a chromatographic standard curve; can be used for verification / calibration of on-site nerve agent measuring instruments to meet the demand for traceability of the value of phosphorus-containing monitors and ensure the accuracy of the value of the measuring instruments; can be used for calibration of new types of organophosphorus measuring equipment during the development process to provide a reference basis for improving the reliability and accuracy of the testing equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The present invention is a process flow chart of the distillation and purification method of crude diethyl chlorophosphate. DETAILED DESCRIPTION

[0015] The present invention is further described below in conjunction with specific embodiments. Example 1

[0016] Selection of separation conditions: Column: HT-ODS-50-B (50 μm, 100 x 450 mm) Mobile phase: A mobile phase is water, B mobile phase is methanol Flow rate: (100~150) mL·min-1 Sample volume: 100mL Distillation purification process The method for rectifying and purifying crude diethyl chlorophosphonate comprises the following steps: (1) Sampling: Use a measuring cylinder to measure 100 ml of crude product for later use; (2) Chromatographic column balance: Mobile phase A is water, and mobile phase B is methanol. After the chromatographic column is connected, if the instrument is running well, flush the system at a flow rate of 150 mL·min-1 and 5% mobile phase B for 30 min. This step is to balance the chromatography. (3) Loading: After balancing, place pipe A in the crude product measuring cylinder and load the crude product through pump A at a rate of 130 mL·min-1. After loading, stop the pump and replace it with water phase to flush pipe A at a rate of 100 mL·min-1 for 20 seconds, then stop the pump. Finally, replace pipe A with mobile phase A. (4) Elution: After loading, start running the gradient conditions, flushing with 5% B mobile phase for 60 min, and then switching to 100% B to flush the column for 30 min; (5) Collection: When the main peak appears in the analytical peak segment of the instrument, start segmented collection, collecting one tube every 3 minutes; (6) Impurity flushing: After collection, flush with 100% methanol until the instrument peak disappears and the impurities are completely flushed. Stop the pump and the initial separation process is completed.

[0017] (7) Post-processing Combine the components that are better separated after separation and preparation, add about 50ml of 10% methanol-water mixture, shake well and let stand for 10min; Then add 50 ml of dichloromethane and ethanol extract (dichloromethane: ethanol = 500: 1) for distillation. Use an oscillator to shake for 30 minutes and then let it stand for 2-3 hours. Keep the liquid below and distill under reduced pressure at 80°C and a vacuum degree of -0.1 MPa for 80-100 minutes to obtain a diethyl chlorophosphate component with higher purity. The purity can be increased to more than 99.6% through separation treatment.

Claims

1. A method for rectifying and purifying crude diethyl chlorophosphate, characterized in that: The following steps are involved: (1) Column balance: Mobile phase A is water, and mobile phase B is methanol. After the column is connected, if the instrument is running well, flush the system with 5% methanol mobile phase at a flow rate of 150 mL min-1 for 30 min. (2) Loading: After equilibration, place pipe A in a measuring cylinder containing crude diethyl chlorophosphate and load the crude product through pump A at a rate of 130 mL·min-1. After loading, stop the pump and replace it with water phase to flush pipe A at a rate of 100 mL·min-1 for 20 seconds, then stop the pump. Finally, replace pipe A with mobile phase A. (3) Elution: After loading, start gradient elution, flush with 5% methanol mobile phase for 60 min, and then change to 100% methanol to flush the column for 30 min; (4) Collection: When the main peak appears in the analytical peak segment of the instrument, start segmented collection, collecting one tube every 3 minutes; (5) Impurity flushing: After collection, flush with 100% methanol until the instrument peaks disappear, which means the impurities have been completely flushed. Stop the pump and the early separation process is completed. (6) Post-treatment: Combine the separated components, add 10% methanol-water mixture, shake well and let stand for 10 min; then add dichloromethane and ethanol extract for distillation, shake with an oscillator and let stand, retain the liquid below, and then perform vacuum distillation to obtain purified diethyl chlorophosphate.

2. A method for rectifying and purifying crude diethyl chlorophosphate according to claim 1, characterized in that, The volume ratio of the crude diethyl chlorophosphate in the measuring cylinder of step (2) to the 10% methanol-water mixture in step (6) is 5:

3.

3. A method for rectifying and purifying crude diethyl chlorophosphate according to claim 1, characterized in that, In step (6), the volume ratio of dichloromethane to ethanol in the dichloromethane-ethanol extract is 500:

1.

4. A method for rectifying and purifying crude diethyl chlorophosphate according to claim 1, characterized in that: In step (6), the mixture is shaken on an oscillator for 30 minutes and then allowed to stand for 2 to 3 hours.

5. A method for rectifying and purifying crude diethyl chlorophosphate according to claim 1, characterized in that: The temperature of the reduced pressure distillation in step (6) is 80° C., the vacuum degree is -0.1 MPa, and the reduced pressure distillation time is 80 to 100 min.

6. A method for rectifying and purifying crude diethyl chlorophosphate according to claim 1, characterized in that: The concentration of the purified diethyl chlorophosphate obtained in step (6) is above 99.6%.

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