CN111886220A - Preparation method of DL-lysine - Google Patents

Abstract

The invention discloses a preparation method of DL-lysine, which comprises the following steps: and stirring the L-lysine hydrochloride, the glacial acetic acid and the water, heating to 70-80 ℃, keeping the temperature, stirring for 1-6 hours, performing suction filtration to obtain a solid, rinsing and drying the solid to obtain the DL-lysine hydrochloride. Dissolving DL-lysine hydrochloride in water, and adjusting the pH value to 5.0 to obtain upper column liquid. Adding the column-loading solution into cation exchange column, eluting with water until the effluent liquid contains no chloride ion, eluting with liquid alkali, and collecting the effluent liquid during liquid alkali elution. Vacuum distilling the collected effluent liquid during liquid caustic elution at 55-60 ℃ under reduced pressure, standing in an oxygen-free environment until crystals are completely separated out, and drying the crystals to obtain the DL-lysine. The preparation method of the DL-lysine has the advantages of simple processing technology, convenient industrial operation, short reaction time, great improvement of the yield and the quality of the DL-lysine product, and better market competitiveness.

Description

A kind of preparation method of DL-lysine

technical field

The invention relates to the field of biotechnology, in particular to a preparation method of DL-lysine.

Background technique

DL-lysine is one of the main raw materials for the synthesis of lysine. The processing technology of DL-lysine in the prior art has many processing steps, and needs to invest a lot of manpower and material resources in the processing process, which is inconvenient for industrialized operation. The production cycle is long, the production cost is increased, and the quality of the prepared DL-lysine is poor, and the market competitiveness is poor. The processing technology of DL-lysine in the prior art is also likely to cause excessive impurities in the product, yellowing in color, and failure to meet the quality requirements. Subsequent processing is required for products that do not meet the quality standards, resulting in excessive processing costs.

Therefore, it is necessary to propose a new preparation method of DL-lysine to simplify the processing steps, improve the processing efficiency and reduce the processing cost.

SUMMARY OF THE INVENTION

In order to overcome the defects in the prior art, the embodiment of the present invention provides a preparation method of DL-lysine, which has simple processing technology, convenient industrial operation, short reaction time, and greatly improves the yield of DL-lysine products. and quality, with better market competitiveness.

The invention discloses a preparation method of DL-lysine, comprising the following steps:

The L-lysine hydrochloride, glacial acetic acid and water are stirred and heated to 70°C to 80°C, and after continuing to keep stirring for 1 to 6 hours, the solid is filtered off with suction, and the solid is rinsed and dried to obtain DL-lysine salt. acid;

Dissolve DL-lysine hydrochloride in water, and adjust the pH value to 5.0 to obtain the upper column liquid;

The upper column liquid is added to the cation exchange column, eluted with water until the effluent does not contain chloride ions, and then eluted with liquid caustic soda, and the effluent during the liquid caustic elution is collected;

The effluent from the collected liquid alkali elution is distilled under reduced pressure and vacuum at 55°C to 60°C, and then left to stand in an oxygen-free environment until the crystals are completely precipitated, and the crystals are dried to obtain DL-lysine.

Preferably, in the step of "raising the temperature of L-lysine hydrochloride, glacial acetic acid and water to 70°C to 80°C with stirring", the weight ratio of L-lysine hydrochloride, glacial acetic acid and water is 1 :(2～2.6):(0.4～1).

Preferably, in the step of "raising the temperature of L-lysine hydrochloride, glacial acetic acid and water to 70°C to 80°C with stirring", the weight ratio of L-lysine hydrochloride, glacial acetic acid and water is 1 :2.6:0.4.

Preferably, in the step of "rinsing and drying the solid to obtain DL-lysine hydrochloride", the method for rinsing the solid is as follows: the solid is stirred and washed for 10-15 minutes by using 95% ethanol with twice the volume of the solid, and centrifuged The liquid is removed, and then the solid is stirred and washed with 95% ethanol with a volume of 0.5 to 1 times the solid for 10 to 15 minutes, and the liquid is removed by centrifugation.

Preferably, in the step "rinsing and drying the solid to obtain DL-lysine hydrochloride", the drying temperature is 70°C to 80°C.

Preferably, in the step "dissolving DL-lysine hydrochloride in water, and adjusting pH to 5.0 to obtain upper column liquid", the weight ratio of DL-lysine hydrochloride and water is 1:( 2 to 4).

Preferably, in the step "dissolving DL-lysine hydrochloride in water, and adjusting the pH to 5.0 to obtain the upper column liquid", a 12%-15% dilute hydrochloric acid solution is used to adjust the pH value.

Preferably, in the step "adding the upper column liquid to the cation exchange column, eluting with water until the effluent does not contain chloride ions, then eluting with liquid caustic soda, and collecting the effluent during the elution with liquid caustic soda", the upper The column liquid is added to the cation exchange column and kept for 0.5h to 1h before subsequent elution.

Preferably, in the step of "adding the upper column liquid to the cation exchange column, eluting with water until the effluent does not contain chloride ions, then eluting with liquid caustic soda, and collecting the effluent during elution with liquid caustic soda", the The concentration of liquid caustic soda is 7%-8%.

Preferably, in the step "decompression and vacuum distillation of the effluent during elution of the collected liquid caustic soda at 55°C to 60°C", the effluent during the elution of the liquid caustic soda is vacuum distilled to a solid content of 60% ~63%.

The beneficial effects of the present invention are as follows:

The preparation method of DL-lysine of the invention has simple processing technology, convenient industrial operation, short reaction time, greatly improves the yield and quality of DL-lysine products, and has better market competitiveness.

In order to make the above-mentioned and other objects, features and advantages of the present invention more obvious and easy to understand, the preferred embodiments are exemplified below, and are described in detail as follows in conjunction with the accompanying drawings.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.

Fig. 1 is the reaction schematic diagram of preparation method of the present invention;

Figure 2 is a flow chart of the preparation method of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The quality indexes of the raw and auxiliary materials used in Examples 1 to 4 and Comparative Example 1 are as follows in Table 1:

Table 1

The color of L-lysine hydrochloride used in Examples 1 to 4 and Comparative Example 1 needs to be white or off-white to be qualified. If the material color is yellow or other, it is unqualified.

Example 1

To prepare DL-Lysine hydrochloride:

The reaction solution consisting of 100Kg of L-lysine hydrochloride, 40Kg of pure water and 260Kg of glacial acetic acid was put into a 1000L reactor, stirred and heated to 70°C to 80°C, and kept stirring for 2h. The L-lysine hydrochloride in the reaction solution fully undergoes a racemization reaction to generate DL-lysine hydrochloride. At this time, the optical rotation value of the reaction solution is 0.

Cool the reaction solution after the racemization reaction in the previous step to 25°C, and use a plastic suction filter barrel to suction filter the solids in the reaction solution into a clean revolving kettle. Rinse and pump the solid into the washing kettle with a small amount of 95wt% ethanol, add 95wt% ethanol 2 times the solid volume to the washing kettle to wash the solid for 10-15min, remove the washing liquid by centrifugation, and then add 0.5 times the solid volume 95wt% ethanol Rinse the solid for 10-15 minutes, remove the washing liquid by centrifugation after rinsing, place the solid in a desiccator, and dry at 70°C to 80°C to obtain DL-lysine hydrochloride.

To prepare DL-Lysine:

Put 275Kg of tap water and 100Kg of DL-lysine hydrochloride into a 1000L glass-lined reactor, stir until completely dissolved, and adjust the pH value to 5.0 with 12%-15% dilute hydrochloric acid to obtain the upper column liquid.

Add the upper column liquid to the cation exchange column, keep it for 0.5h first so that the upper column liquid is fully adsorbed by the resin particles in the cation exchange column, and then elute with tap water until the pH value of the effluent is 6-7, and then rinse with pure water. Cation exchange column, so that the chloride ions in the effluent are eluted and removed, that is, no chloride ions can be detected in the effluent.

After the chloride ions are completely removed, the cation exchange column is eluted with 8% liquid caustic soda, and the effluent from the liquid caustic elution is collected.

The effluent from the collected liquid caustic soda elution was distilled under reduced pressure and vacuum at 55°C to 60°C to a solid content of 60% to 63%, and then placed in a clean plastic bucket, and allowed to stand at 25°C in an oxygen-free environment until The crystals were completely precipitated, the excess liquid was removed by centrifugation, and the DL-lysine sample 1 was obtained after the crystals were dried at 65°C.

The quality index of the DL-lysine sample 1 prepared in this example is as follows in Table 2:

Table 2

Quality Index Index value Exterior: Off-white crystals. Specific Rotation: +0.5°～-0.5° Absorbance: ≤0.10 proportion: 1.120～1.135 pH: 9.9～10.3(5%v/v) chloride: <500ppm content: 49.0～51.0% TLC: (single heteroacid) ≤0.4% (Total Miscellaneous Acids): ≤1%

Example 2

To prepare DL-Lysine hydrochloride:

The reaction solution consisting of 100Kg of L-lysine hydrochloride, 40Kg of pure water and 200Kg of glacial acetic acid was put into a 1000L reaction kettle, stirred and heated to 75°C, and kept stirring for 2h.

Cool the reaction solution after the racemization reaction in the previous step to 25°C, and use a plastic suction filter barrel to suction filter the solids in the reaction solution into a clean revolving kettle. Rinse and pump the solid into the washing kettle with a small amount of 95wt% ethanol, add 95wt% ethanol 2 times the solid volume to the washing kettle to wash the solid for 10-15min, remove the washing liquid by centrifugation, and then add 0.5 times the solid volume 95wt% ethanol Rinse the solid for 10-15 minutes, remove the washing liquid by centrifugation after rinsing, place the solid in a desiccator, and dry at 70-80° C. to obtain DL-lysine hydrochloride.

To prepare DL-Lysine:

Put 275Kg of tap water and 100Kg of DL-lysine hydrochloride into a 1000L glass-lined reactor, stir until completely dissolved, and adjust the pH value to 5.0 with 12%-15% dilute hydrochloric acid to obtain the upper column liquid.

Add the upper column liquid to the cation exchange column, keep it for 0.5h first so that the upper column liquid is fully adsorbed by the resin particles in the cation exchange column, and then elute with tap water until the pH value of the effluent is 6-7, and then rinse with pure water. Cation exchange column until no chloride ions can be detected in the effluent.

After the chloride ions are completely removed, the cation exchange column is eluted with 8% liquid caustic soda, and the effluent from the liquid caustic elution is collected.

The effluent from the collected liquid caustic soda elution was distilled under reduced pressure and vacuum at 55°C to 60°C to a solid content of 60% to 63%, and then placed in a clean plastic bucket, and allowed to stand at 25°C in an oxygen-free environment until The crystals were completely precipitated, the excess liquid was removed by centrifugation, and the DL-lysine sample 2 was obtained after the crystals were dried at 65°C.

The quality index of the DL-lysine sample 2 prepared in this example is as follows in Table 3:

table 3

Quality Index Index value Exterior: Off-white crystals. Specific Rotation: +0.5°～-0.5° Absorbance: ≤0.10 proportion: 1.120～1.135 pH: 9.9～10.3(5%v/v) chloride: <500ppm content: 49.0～51.0% TLC: (single heteroacid) ≤0.4% (Total Miscellaneous Acids): ≤1%

Example 3

To prepare DL-Lysine hydrochloride:

The reaction solution consisting of 100Kg of L-lysine hydrochloride, 40Kg of pure water and 260Kg of glacial acetic acid was put into a 1000L reaction kettle, stirred and heated to 75°C, and kept stirring for 1 hour.

Cool the reaction solution after the racemization reaction in the previous step to 25°C, and use a plastic suction filter barrel to suction filter the solids in the reaction solution into a clean revolving kettle. Rinse and pump the solid into the washing kettle with a small amount of 95wt% ethanol, add 95wt% ethanol 2 times the solid volume to the washing kettle to wash the solid for 10-15min, remove the washing liquid by centrifugation, and then add 0.5 times the solid volume 95wt% ethanol Rinse the solid for 10-15 minutes, remove the washing liquid by centrifugation after rinsing, place the solid in a desiccator, and dry at 70-80° C. to obtain DL-lysine hydrochloride.

To prepare DL-Lysine:

Put 275Kg of tap water and 100Kg of DL-lysine hydrochloride into a 1000L glass-lined reactor, stir until completely dissolved, and adjust the pH value to 5.0 with 12%-15% dilute hydrochloric acid to obtain the upper column liquid.

Add the upper column liquid to the cation exchange column, keep it for 0.5h first so that the upper column liquid is fully adsorbed by the resin particles in the cation exchange column, and then elute with tap water until the pH value of the effluent is 6-7, and then rinse with pure water. Cation exchange column until no chloride ions can be detected in the effluent.

After the chloride ion is completely removed, it is eluted with 8% liquid caustic soda, and the effluent of the liquid caustic elution is collected.

The effluent from the collected liquid caustic soda elution was distilled under reduced pressure and vacuum at 55°C to 60°C to a solid content of 60% to 63%, and then placed in a clean plastic bucket, and allowed to stand at 25°C in an oxygen-free environment until The crystals were completely precipitated, the excess liquid was removed by centrifugation, and the DL-lysine sample 3 was obtained after the crystals were dried at 65°C.

The quality index of the DL-lysine sample 3 prepared in this example is as follows in Table 4:

Table 4

Quality Index Index value Exterior: Off-white crystals. Specific Rotation: +0.5°～-0.5° Absorbance: ≤0.10 proportion: 1.120～1.135 pH: 9.9～10.3(5%v/v) chloride: <500ppm content: 49.0～51.0% TLC: (single heteroacid) ≤0.4% (Total Miscellaneous Acids): ≤1%

Example 4

To prepare DL-Lysine hydrochloride:

The reaction solution consisting of 100Kg of L-lysine hydrochloride, 100Kg of pure water and 260Kg of glacial acetic acid was put into a 1000L reaction kettle, stirred and heated to 75°C, and kept stirring for 6h.

Cool the reaction solution after the racemization reaction in the previous step to 25°C, and use a plastic suction filter barrel to suction filter the solids in the reaction solution into a clean revolving kettle. Rinse and pump the solid into the washing kettle with a small amount of 95wt% ethanol, add 95wt% ethanol 2 times the solid volume to the washing kettle to wash the solid for 10-15min, remove the washing liquid by centrifugation, and then add 0.5 times the solid volume 95wt% ethanol Rinse the solid for 10-15 minutes, remove the washing liquid by centrifugation after rinsing, place the solid in a desiccator, and dry at 70-80° C. to obtain DL-lysine hydrochloride.

To prepare DL-Lysine:

Put 275Kg of tap water and 100Kg of DL-lysine hydrochloride into a 1000L glass-lined reactor, stir until completely dissolved, and adjust the pH value to 5.0 with 12%-15% dilute hydrochloric acid to obtain the upper column liquid.

Add the upper column liquid to the cation exchange column, keep it for 0.5h first so that the upper column liquid is fully adsorbed by the resin particles in the cation exchange column, and then elute with tap water until the pH value of the effluent is 6-7, and then rinse with pure water. Cation exchange column until no chloride ions can be detected in the effluent.

After the chloride ion is completely removed, it is eluted with 8% liquid caustic soda, and the effluent of the liquid caustic elution is collected.

The effluent from the collected liquid caustic soda elution was distilled under reduced pressure and vacuum at 55°C to 60°C to a solid content of 60% to 63%, and then placed in a clean plastic bucket, and allowed to stand at 25°C in an oxygen-free environment until The crystals were completely precipitated, the excess liquid was removed by centrifugation, and the DL-lysine sample 4 was obtained after the crystals were dried at 65°C.

The quality index of the DL-lysine sample 4 prepared in this example is as follows in Table 5:

table 5

Quality Index Index value Exterior: Off-white crystals. Specific Rotation: +0.5°～-0.5° Absorbance: ≤0.10 proportion: 1.120～1.135 pH: 9.9～10.3(5%v/v) chloride: <500ppm content: 49.0～51.0% TLC: (single heteroacid) ≤0.4% (Total Miscellaneous Acids): ≤1%

Comparative Example 1

The difference between this comparative example and Example 1 is that, when DL-lysine is prepared, the effluent from the collected liquid caustic elution is distilled under reduced pressure and vacuum at 80°C to 85°C.

To prepare DL-Lysine hydrochloride:

The reaction solution consisting of 100Kg of L-lysine hydrochloride, 40Kg of pure water and 260Kg of glacial acetic acid was put into a 1000L reaction kettle, stirred and heated to 75°C, and kept stirring for 2h.

Cool the reaction solution after the racemization reaction in the previous step to 25°C, and use a plastic suction filter barrel to suction filter the solids in the reaction solution into a clean revolving kettle. Rinse and pump the solid into the washing kettle with a small amount of 95wt% ethanol, add 95wt% ethanol 2 times the solid volume to the washing kettle to wash the solid for 10-15min, remove the washing liquid by centrifugation, and then add 0.5 times the solid volume 95wt% ethanol Rinse the solid for 10-15 minutes, remove the washing liquid by centrifugation after rinsing, place the solid in a desiccator, and dry at 70-80° C. to obtain DL-lysine hydrochloride.

To prepare DL-Lysine:

Put 275Kg of tap water and 100Kg of DL-lysine hydrochloride into a 1000L glass-lined reactor, stir until completely dissolved, and adjust the pH value to 5.0 with 12%-15% dilute hydrochloric acid to obtain the upper column liquid.

Add the upper column liquid to the cation exchange column, keep it for 0.5h first so that the upper column liquid is fully adsorbed by the resin particles in the cation exchange column, and then elute with tap water until the pH value of the effluent is 6-7, and then rinse with pure water. Cation exchange column until no chloride ions can be detected in the effluent.

After the chloride ion is completely removed, it is eluted with 8% liquid caustic soda, and the effluent of the liquid caustic elution is collected.

Distill the effluent from the collected liquid caustic soda under reduced pressure and vacuum at 80°C to 85°C to a solid content of 60% to 63%, then place it in a clean plastic bucket, and let it stand at 25°C in an oxygen-free environment until The crystals were completely precipitated, the excess liquid was removed by centrifugation, and the DL-lysine sample 5 was obtained after the crystals were dried at 65°C.

The quality index of the DL-lysine sample 5 prepared in this example is as follows in Table 6:

Table 6

Quality Index Index value Exterior: Off-white crystals. Specific Rotation: +0.5°～-0.5° Absorbance: 0.80 proportion: 1.120～1.135 pH: 9.9～10.3(5%v/v) chloride: <500ppm content: 43.8～45.8% TLC: (single heteroacid) 2.08% (Total Miscellaneous Acids): 5.2%

The yields of the samples in Examples 1 to 4 and Comparative Example 1 are shown in Table 7 below.

Table 7

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 yield 67.2% 50.2% 49.5% 66.2% 60.4%

The DL-lysine prepared in Examples 1 to 4 of the present invention has good quality. Among them, the preparation method in Example 1 is the best method, and the DL-lysine prepared by the preparation method in Example 1 has better quality and higher yield.

The color of L-lysine hydrochloride used in Examples 1 to 4 of the present invention and Comparative Example 1 is white or off-white, which ensures that the color index of the product is qualified. If the raw material L-lysine hydrochloride used is yellow or other, it is unqualified. The use of L-lysine hydrochloride after moisture absorption and oxidation discoloration will affect the appearance and absorbance of the finished product, resulting in the unqualified color index of the finished product.

Compared with Example 1, Example 2 of the present invention reduces the amount of glacial acetic acid, so that the L-lysine hydrochloride racemization reaction is incomplete, resulting in a low 17% yield of the final product, but the quality is not affected.

Compared with Example 1, Example 3 of the present invention reduces the time of the racemization reaction, only 1h of the racemization reaction results in incomplete racemization reaction and reduces the yield of the product, but has no effect on the quality of the product.

Compared with Example 1, Example 4 of the present invention increases the dosage of pure water when racemizing L-lysine hydrochloride to prepare DL-lysine hydrochloride. During the racemization reaction, the optical rotation value of the reaction solution was tracked, and it was found that after the reaction time reached 6 hours, the optical rotation value of the reaction solution was 0, that is, the reaction was complete. Therefore, if the amount of pure water is too high, it will increase the reaction time and reduce the production efficiency, but it will not affect the quality and yield of the product.

Compared with Example 1 in Comparative Example 1 of the present invention, when DL-lysine is prepared, the effluent from the collected liquid caustic elution is distilled under reduced pressure and vacuum at 80°C to 85°C. -The lysine sample is oxidized to yellow, and the final color is light yellow. During the high-temperature distillation process, the DL-lysine sample produces more derivatives, such as miscellaneous acids, resulting in non-compliance with the product quality indicators and reducing the product quality. yield. However, in Examples 1 to 4 of the present invention, the effluent of the collected liquid caustic soda was eluted at 55°C to 60°C under reduced pressure and vacuum distillation, and the obtained DL-lysine samples had good quality indicators.

In Examples 1 to 4 of the present invention, the liquid caustic soda with a concentration of 8% is used to elute the product, and the sodium ions in the liquid caustic can replace the DL-lysine in the cation exchange column. If the concentration of the liquid caustic is too low , it will lead to insufficient elution, incomplete collection, and high concentration of liquid alkali will damage the resin particles in the cation exchange column. In the present invention, the concentration of the liquid alkali is selected to be 8%, which can fully elute the DL-lysine in the cation exchange column without damaging the cation exchange column.

In Examples 1 to 4 of the present invention, the effluent during the elution of the collected liquid caustic soda was distilled under reduced pressure and vacuum at 55°C to 60°C, and then left to stand in an oxygen-free environment until the crystals were completely precipitated, and the crystals were dried to obtain DL-Lysine. In the preparation process, the contact between the DL-lysine and the oxygen is reduced, the DL-lysine can be prevented from being oxidized and turned yellow, and the finished product has a good quality.

In Examples 1 to 4 of the present invention, during the elution process, tap water was used to elute the pH of the effluent to 6 to 7, then pure water was used to rinse the cation exchange column, and tap water was used to elute first, which could reduce the amount of pure water. This reduces the time required to prepare large quantities of pure water. When tap water is eluted to the pH value of 6-7 effluent, a large amount of chloride ions have been removed, and then use pure water to continue to rinse the cation exchange column until the chloride ions are completely removed, so that the production results are more accurate.

In the present invention, the principles and implementations of the present invention are described by using specific embodiments, and the descriptions of the above embodiments are only used to help understand the method and the core idea of the present invention; The idea of the invention will have changes in the specific implementation and application scope. To sum up, the content of this specification should not be construed as a limitation to the present invention.

Claims (10)

1. a preparation method of DL-lysine, is characterized in that, comprises the following steps: The L-lysine hydrochloride, glacial acetic acid and water are stirred and heated to 70°C to 80°C, and after continuing to keep stirring for 1 to 6 hours, the solid is filtered off with suction, and the solid is rinsed and dried to obtain DL-lysine salt. acid; Dissolve DL-lysine hydrochloride in water, and adjust the pH value to 5.0 to obtain the upper column liquid; The upper column liquid is added to the cation exchange column, eluted with water until the effluent does not contain chloride ions, and then eluted with liquid caustic soda, and the effluent during the liquid caustic elution is collected; The effluent from the collected liquid alkali elution is distilled under reduced pressure and vacuum at 55°C to 60°C, and then left to stand in an oxygen-free environment until the crystals are completely precipitated, and the crystals are dried to obtain DL-lysine. 2. the preparation method of DL-Lysine according to claim 1, is characterized in that, in described step " L-Lysine hydrochloride, glacial acetic acid and water are stirred and warmed up to 70 ℃～80 ℃ " , the weight ratio of L-lysine hydrochloride, glacial acetic acid and water is 1:(2～2.6):(0.4～1). 3. the preparation method of DL-Lysine according to claim 1, is characterized in that, in described step " L-Lysine hydrochloride, glacial acetic acid and water are stirred and warmed up to 70 ℃～80 ℃ " , the weight ratio of L-lysine hydrochloride, glacial acetic acid and water is 1:2.6:0.4. 4. the preparation method of DL-Lysine according to claim 1, is characterized in that, in described step " by solid rinsing, drying, obtains DL-Lysine hydrochloride ", solid rinsing method is: The solid is stirred and washed for 10-15 minutes with 95% ethanol with 2 times the solid volume, and the liquid is removed by centrifugation. 5. the preparation method of DL-lysine according to claim 1, is characterized in that, in described step " rinsing, drying solid, obtains DL-lysine hydrochloride ", drying temperature is 70 ℃ ~80°C. 6. the preparation method of DL-lysine according to claim 1, is characterized in that, described step " is dissolved in water with DL-lysine hydrochloride, and regulates pH to 5.0, obtains upper column liquid " Among them, the weight ratio of DL-lysine hydrochloride and water is 1:(2～4). 7. the preparation method of DL-Lysine according to claim 1, is characterized in that, described step " is dissolved in DL-Lysine hydrochloride in water, and regulates pH to 5.0, obtains upper column liquid " 12% to 15% dilute hydrochloric acid solution was used to adjust the pH value. 8. the preparation method of DL-Lysine according to claim 1, is characterized in that, described step " adds upper column liquid in cation exchange column, is eluted with water to effluent without chloride ion, and then uses Elution with liquid caustic soda, collect the effluent during elution with caustic soda", add the upper column liquid to the cation exchange column, keep it for 0.5h to 1h, and then carry out subsequent elution. 9. the preparation method of DL-lysine according to claim 1, is characterized in that, described step " adds upper column liquid in cation exchange column, is eluted with water to the effluent that does not contain chloride ion, then uses Elution of liquid caustic soda, collecting the effluent during elution of liquid caustic soda", the concentration of the liquid caustic soda is 7% to 8%. 10. the preparation method of DL-Lysine according to claim 1, is characterized in that, in described step " in 55 ℃～60 ℃ of underpressure vacuum distillation of the effluent when the collected liquid alkali is washed out ", The effluent from the liquid alkali elution is vacuum-distilled under reduced pressure to a solid content of 60% to 63%.

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