CN116478055A - Chiral refining method of aspartic acid - Google Patents

Abstract

The invention discloses a chiral refining method for aspartic acid, which comprises the following steps: preliminary treatment, pH adjustment, product precipitation and mother liquor treatment. The present invention can recover L-aspartic acid whose optical rotation meets the requirements of use from dense-phase aspartic acid with higher specific optical rotation through a simple chiral purification method, and can be sold with reference to the standards of D and L-aspartic acid to achieve the purpose of reducing costs. Moreover, the overall method is simple and convenient, requires less equipment, and has higher processing efficiency. The remaining primary mother liquor and secondary mother liquor after the precipitation of L-aspartic acid can be treated again to prevent waste. to reduce pollution.

Description

A kind of aspartic acid chiral refining method

technical field

The invention belongs to the technical field of aspartic acid processing, and in particular relates to a chiral refining method of aspartic acid.

Background technique

Aspartic acid, whose chemical name is aminosuccinic acid, is one of the 20 basic amino acids that make up proteins. It is widely used in biochemical reagents and clinical medicine. Aspartic acid is used in the synthesis of sweeteners, and in medicine for treating heart disease. It is used as a liver function enhancer, ammonia antidote, fatigue reliever, and amino acid infusion components. However, after processing various mother liquors in the production of aspartame, recycled aspartic acid with low optical rotation will be produced, which cannot meet the quality standards for direct recycling, resulting in great waste.

Contents of the invention

The object of the present invention is to provide a kind of chiral refining method of aspartic acid, to solve the above-mentioned background technology in the prior art after processing various mother liquors in the production of aspartame, the recovery of aspartic acid with low optical rotation will be produced, which cannot reach the quality standard for direct reuse.

To achieve the above object, the present invention adopts the following technical scheme: a chiral refining method for aspartic acid, comprising the following steps:

S1. Pump 1.5t of dense-phase aspartic acid into an enamel reaction kettle with a volume of 10 cubic meters, then add 5 cubic meters of water to it, and then use a stirrer to stir and mix the mixed solution in the enamel reaction kettle. After stirring and mixing, open the steam valve, and raise the temperature of the mixed solution to 60°C to 65°C;

S2, then add 1.2 cubic meters to 1.5 cubic meters of liquid caustic soda to the mixed solution, then slowly add hydrochloric acid dropwise to the mixed solution to adjust the pH value of the mixed solution to 2.5 to 3.0, and cool the temperature of the mixed solution to 20°C to 30°C through a condenser;

S3. Put a small amount of L-aspartic acid into the mixed solution as a seed crystal, and utilize the inconsistency in the degree of solubility change of L and D-type aspartic acid in the process of temperature drop, so that L-aspartic acid is preferentially precipitated, and then keep the temperature of the mixed solution within the range of 20°C to 30°C, so that most of the D-type aspartic acid remains in the mixed solution, and then transfer the precipitated L-aspartic acid to a centrifuge for centrifugation to obtain a precipitate and a first-grade mother liquor, and dry the precipitate to obtain L-aspartic acid. Partic acid;

S4. Then pump the primary mother liquor into a new enamel reaction kettle, heat it to 50°C-70°C, add calcium hydroxide to adjust the pH of the first-stage mother liquor to 10-12, and then use a stirrer to stir it for a period of time. After the stirring is completed, the first-stage mother liquor will separate the calcium sulfate solid and the second-stage mother liquor. Finally, the second-stage mother liquor will be reheated to 50-60°C, and then the clarified second-stage mother liquor is used in S1 through filter press filtration. Repeat the above steps until no second mother liquor is produced.

Preferably, the specific optical rotation of the concentrated phase of aspartic acid in the S1 is greater than 18°, and the stirring time of the mixed solution in the S1 is 3h-5h.

Preferably, the liquid caustic soda added in the S2 is sodium hydroxide solution, and the mass concentration of the sodium hydroxide solution is 32%.

Preferably, before adding water in the S1, it is necessary to add activated carbon particles to the dense-phase aspartic acid for soaking and absorbing impurities in the concentrated-phase aspartic acid. The soaking time is 2h to 4h, and the soaked dense-phase aspartic acid and activated carbon mixture is filtered to obtain a filtrate.

Preferably, the L-aspartic acid obtained in S3 can be used mechanically after drying if its optical rotation and water content meet the requirements. If the optical rotation still fails to meet the requirements, the wet product can be used for secondary refining.

Preferably, the L-aspartic acid added to the mixed solution in S3 is in the form of powder, and the weight of the added L-aspartic acid is 6%-10% of the total amount of the mixed solution.

Preferably, ammonia gas will be generated in the first-stage mother liquor after calcium hydroxide is added in the S4. At this time, the ammonia gas needs to be extracted from the enamel reaction kettle through an air pump, and the extracted ammonia gas can be used for adjusting the pH of the mixed solution in S2.

Preferably, in S4, the time for stirring the primary mother liquor with a stirrer is 4h to 6h, and in S4, it is necessary to add ammonium bicarbonate to the secondary mother liquor to adjust the calcium ion concentration in the secondary mother liquor to less than 0.05 mol/L before press-filtering the secondary mother liquor.

A kind of aspartic acid chiral refining method that the present invention proposes, compared with prior art, has following advantage:

The present invention can recover L-aspartic acid whose optical rotation meets the requirements of use from dense-phase aspartic acid with higher specific optical rotation through a simple chiral purification method. It can be sold with reference to the standards of D and L-aspartic acid to achieve the purpose of reducing costs, and the overall method is simple and convenient, with less equipment used and high processing efficiency. The remaining primary mother liquor and secondary mother liquor after the precipitation of L-aspartic acid can be treated again to prevent waste. to reduce pollution.

Description of drawings

Fig. 1 is a flowchart of the present invention.

Implementation

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. The specific embodiments described here are only used to explain the present invention, not to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example

The present invention provides a kind of aspartic acid chiral refining method as shown in Figure 1, comprises the following steps:

S1. Preliminary treatment: pump 1.5t of dense-phase aspartic acid into an enamel reaction kettle with a volume of 10 cubic meters, then add 5 cubic meters of water to it, and then use a stirrer to stir and mix the mixed solution in the enamel reaction kettle. After stirring and mixing, open the steam valve and raise the temperature of the mixed solution to 60°C. The specific rotation of the concentrated-phase aspartic acid is greater than 18°. The mixing time of the mixed solution is 3 hours. Before adding water, activity needs to be added to the concentrated-phase aspartic acid. The carbon particles are used for soaking and adsorbing impurities in dense-phase aspartic acid. The soaking time is 2 hours. After soaking, the mixture of dense-phase aspartic acid and activated carbon is filtered to obtain the filtrate;

S2, PH adjustment, then add 1.2 cubic meters of liquid caustic soda to the mixed solution, slowly add hydrochloric acid dropwise to the mixed solution to adjust the pH value of the mixed solution to 2.5, and cool the temperature of the mixed solution to 20°C through the condenser, the added liquid caustic soda is sodium hydroxide solution, and the mass concentration of sodium hydroxide solution is 32%;

S3, product precipitation, and then put a small amount of L-aspartic acid into the mixed solution as a seed crystal, using the characteristics of L and D-type aspartic acid in the process of temperature decrease in the degree of inconsistency in solubility change, so that L-aspartic acid is preferentially precipitated, and then keep the temperature of the mixed solution at 20 ° C, so that most of the D-type aspartic acid remains in the mixed solution, and then transfer the precipitated L-aspartic acid to a centrifuge for centrifugation to obtain precipitation and primary mother liquor, and dry the precipitate to obtain L-aspartic acid , the optical rotation and moisture content of the obtained L-aspartic acid after drying meet the requirements and can be used mechanically. If the optical rotation still does not meet the requirements, the wet product can be put into refining for the second time, and the L-aspartic acid added in the mixed solution is powdery, and the weight of the added L-aspartic acid is 6% of the total amount of the mixed solution;

S4, mother liquor treatment, then pump the primary mother liquor into a new enamel reaction kettle, heat it to 50°C, add calcium hydroxide to adjust the pH of the first-stage mother liquor to 10, and then use a stirrer to stir it for a period of time, after the stirring is completed, the first-stage mother liquor will separate calcium sulfate solids and the second-order mother liquor, and finally reheat the second-order mother liquor to 50°C, and then use a filter press to obtain a clarified second-order mother liquor. Ammonia gas will be generated. At this time, the ammonia gas needs to be extracted from the enamel reaction kettle through an air pump. The extracted ammonia gas can be used to adjust the pH of the mixed solution in S2. The time for stirring the primary mother liquor with a stirrer is 4 hours. Before pressing the secondary mother liquor, it is necessary to add ammonium bicarbonate to it to adjust the calcium ion concentration in the secondary mother liquor to less than 0.05mol/L.

Example

A chiral refining method for aspartic acid, comprising the following steps:

S1. Preliminary treatment: pump 1.5t of dense-phase aspartic acid into an enamel reaction kettle with a volume of 10 cubic meters, then add 5 cubic meters of water to it, and then use a stirrer to stir and mix the mixed solution in the enamel reaction kettle. After stirring and mixing, open the steam valve to raise the temperature of the mixed solution to 63°C. The specific rotation of the concentrated-phase aspartic acid is greater than 18°. The mixing time of the mixed solution is 4 hours. Before adding water, activity needs to be added to the concentrated-phase aspartic acid. The carbon particles are used for soaking and adsorbing impurities in dense-phase aspartic acid. The soaking time is 3 hours. After soaking, the mixture of dense-phase aspartic acid and activated carbon is filtered to obtain the filtrate;

S2, pH adjustment, then add 1.35 cubic meters of liquid caustic soda to the mixed solution, then slowly add hydrochloric acid dropwise to the mixed solution to adjust the pH value of the mixed solution to 2.75, and cool the temperature of the mixed solution to 15°C through the condenser, the added liquid caustic soda is sodium hydroxide solution, and the mass concentration of sodium hydroxide solution is 32%;

S3, product precipitation, and then put a small amount of L-aspartic acid into the mixed solution as a seed crystal, and use the characteristics of L and D-type aspartic acid in the process of temperature decrease in the degree of solubility change, so that L-aspartic acid is preferentially precipitated, and then keep the temperature of the mixed solution at 15 ° C, so that most of the D-type aspartic acid remains in the mixed solution, and then transfer the precipitated L-aspartic acid to a centrifuge for centrifugation to obtain precipitation and primary mother liquor, and dry the precipitate to obtain L-aspartic acid , the optical rotation and moisture content of the obtained L-aspartic acid after drying meet the requirements and can be applied mechanically. If the optical rotation still does not meet the requirements, the wet product can be put into refining for the second time, and the L-aspartic acid added in the mixed solution is powdery, and the weight of the added L-aspartic acid is 8% of the total amount of the mixed solution;

S4, mother liquor treatment, then pump the primary mother liquor into a new enamel reaction kettle, heat it to 60°C, add calcium hydroxide to adjust the pH of the first-stage mother liquor to 11, and then use a stirrer to stir it for a period of time. After the stirring is completed, the first-stage mother liquor will separate calcium sulfate solids and the second-order mother liquor, and finally heat the second-order mother liquor to 55°C, and then use a filter press to obtain a clarified second-order mother liquor. Ammonia gas is generated. At this time, the ammonia gas needs to be extracted from the enamel reaction kettle through an air pump. The extracted ammonia gas can be used to adjust the pH of the mixed solution in S2. The stirring time of the first-level mother liquor is 5 hours with a stirrer. Before pressing the second-level mother liquor, it is necessary to add ammonium bicarbonate to it to adjust the calcium ion concentration in the second-level mother liquor to less than 0.05mol/L

Example

A chiral refining method for aspartic acid, comprising the following steps:

S1. Preliminary treatment: pump 1.5t of dense-phase aspartic acid into an enamel reaction kettle with a volume of 10 cubic meters, then add 5 cubic meters of water to it, and then use a stirrer to stir and mix the mixed solution in the enamel reaction kettle. After stirring and mixing, open the steam valve, and raise the temperature of the mixed solution to 65°C. The specific rotation of the concentrated-phase aspartic acid is greater than 18°. The carbon particles are used for soaking and adsorbing impurities in dense-phase aspartic acid. The soaking time is 4 hours. After soaking, the mixture of concentrated-phase aspartic acid and activated carbon is filtered to obtain the filtrate;

S2, pH adjustment, then add 1.5 cubic meters of liquid caustic soda to the mixed solution, slowly add hydrochloric acid dropwise to the mixed solution to adjust the pH value of the mixed solution to 3.0, and cool the temperature of the mixed solution to 30°C through the condenser, the added liquid caustic soda is a sodium hydroxide solution, and the mass concentration of the sodium hydroxide solution is 32%;

S3, product precipitation, and then put a small amount of L-aspartic acid into the mixed solution as a seed crystal, using the characteristics of L and D-type aspartic acid in the process of temperature decrease in the degree of inconsistency in solubility change, so that L-aspartic acid is preferentially precipitated, and then keep the temperature of the mixed solution at 30 ° C, so that most of the D-type aspartic acid remains in the mixed solution, and then transfer the precipitated L-aspartic acid to a centrifuge for centrifugation to obtain precipitation and primary mother liquor, and dry the precipitate to obtain L-aspartic acid , the optical rotation and moisture content of the obtained L-aspartic acid after drying meet the requirements and can be applied mechanically. If the optical rotation still does not meet the requirements, the wet product can be put into refining for the second time, and the L-aspartic acid added in the mixed solution is powdery, and the weight of the added L-aspartic acid is 10% of the total amount of the mixed solution;

S4, mother liquor treatment, then pump the primary mother liquor into a new enamel reaction kettle, heat it to 70°C, add calcium hydroxide to adjust the pH of the first-stage mother liquor to 12, and then use a stirrer to stir it for a period of time. After the stirring is completed, the first-stage mother liquor will separate calcium sulfate solids and the second-order mother liquor, and finally heat the second-order mother liquor to 60°C, and then use a filter press to obtain a clarified second-order mother liquor. Ammonia gas is generated. At this time, the ammonia gas needs to be extracted from the enamel reaction kettle through an air pump. The extracted ammonia gas can be used to adjust the pH of the mixed solution in S2. The time for stirring the primary mother liquor with a stirrer is 6 hours. Before pressing the secondary mother liquor, it is necessary to add ammonium bicarbonate to it to adjust the calcium ion concentration in the secondary mother liquor to less than 0.05mol/L.

Finally, it should be noted that the above is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements to some of the technical features. Within the spirit and principles of the present invention, any modifications, equivalent replacements, improvements, etc., should be included within the scope of protection of the present invention.

Claims (8)

1. A chiral refining method for aspartic acid, comprising the following steps: it is characterized in that: S1. Preliminary treatment: pump 1.5t of dense-phase aspartic acid into an enamel reaction kettle with a volume of 10 cubic meters, then add 5 cubic meters of water to it, and then use a stirrer to stir and mix the mixed solution in the enamel reaction kettle. After stirring and mixing, open the steam valve, and raise the temperature of the mixed solution to 60°C to 65°C; S2, pH adjustment, then add 1.2 cubic meters to 1.5 cubic meters of liquid caustic soda to the mixed solution, then slowly add hydrochloric acid dropwise to the mixed solution to adjust the pH value of the mixed solution to 2.5 to 3.0, and cool the temperature of the mixed solution to 20°C to 30°C through a condenser; S3, product precipitation, and then put a small amount of L-aspartic acid into the mixed solution as a seed crystal, utilize the characteristics of L and D-type aspartic acid in the process of temperature decrease in the degree of solubility change, so that L-aspartic acid is preferentially precipitated, and then keep the temperature of the mixed solution within the range of 20°C to 30°C, so that most of the D-type aspartic acid remains in the mixed solution, and then transfer the precipitated L-aspartic acid to a centrifuge for centrifugation to obtain a precipitate and a first-grade mother liquor, and dry the precipitate to obtain L-aspartic acid; S4, mother liquor treatment, then pump the primary mother liquor into a new enamel reaction kettle, heat it to 50°C-70°C, add calcium hydroxide to adjust the pH of the first-stage mother liquor to 10-12, and then use a stirrer to stir it for a period of time. After the stirring is completed, the first-stage mother liquor will separate the calcium sulfate solid and the second-order mother liquor, and finally reheat the second-order mother liquor to 50-60°C, and then use a filter press to obtain a clarified second-order mother liquor. Use in S1, repeat the above steps until no second mother liquor is produced . 2. A chiral refining method of aspartic acid according to claim 1, characterized in that: the specific rotation of aspartic acid in the concentrated phase in the S1 is greater than 18°, and the stirring time of the mixed solution in the S1 is 3h-5h. 3. A chiral refining method for aspartic acid according to claim 1, characterized in that: the liquid caustic soda added in the S2 is a sodium hydroxide solution, and the mass concentration of the sodium hydroxide solution is 32%. 4. A chiral refining method for aspartic acid according to claim 1, characterized in that: in the S1, before adding water, activated carbon particles need to be added to the dense-phase aspartic acid for soaking and absorbing impurities in the dense-phase aspartic acid, the soaking time is 2h to 4h, and the soaked concentrated-phase aspartic acid and activated carbon mixture is filtered to obtain a filtrate. 5. A chiral refining method for aspartic acid according to claim 1, characterized in that: the optical rotation and water content of the dried L-aspartic acid obtained in the S3 can be applied mechanically if the optical rotation and moisture meet the requirements. If the optical rotation still does not meet the requirements, the wet product can be put into refining for the second time. 6. A chiral refining method for aspartic acid according to claim 1, characterized in that: the L-aspartic acid added to the mixed solution in S3 is powdery, and the weight of the added L-aspartic acid is 6% to 10% of the total amount of the mixed solution. 7. a kind of aspartic acid chiral refining method according to claim 1, it is characterized in that: in described S4, can produce ammonia in the first-level mother liquor after adding calcium hydroxide, this moment needs ammonia to be extracted from enamel reactor by air pump, the described ammonia of extraction can be used in S2 to the pH adjustment of mixed solution. 8. A chiral refining method for aspartic acid according to claim 1, characterized in that: the time for stirring the primary mother liquor with a stirrer in said S4 is 4h to 6h, and in said S4, it is necessary to add ammonium bicarbonate to it to adjust the calcium ion concentration in the secondary mother liquor to be less than 0.05mol/L before the press filtration of the secondary mother liquor.