Method for purifying levocarnitine

Abstract

The invention belongs to the technical field of chemistry, and particularly relates to a method for purifying levocarnitine. The crude product solution is effectively filtered through the composite membrane, various different impurities can be effectively removed through cooperation of the membranes, multiple purification procedures are avoided, meanwhile, purification can be effectively conducted through the temperature and pressure in cooperation with the corresponding pressure, and the purity reaches 99% or above.

Description

Technical Field

[0001] The invention belongs to the technical field of chemistry, and in particular relates to a method for purifying L-carnitine. Background Art

[0002] L-carnitine, also known as L-carnitine or L-carnitine, is an amino acid that promotes the conversion of fat into energy. Red meat is the main source of L-carnitine and has no toxic side effects on the human body.

[0003] At present, the methods for producing L-carnitine on the market include meat juice extraction, chemical synthesis, biosynthesis, etc., but the purity of the prepared L-carnitine is not high, and a large amount of waste will be generated, which will cause huge environmental pressure. Chinese invention patent CN20171033747.0 discloses a production and purification system of L-carnitine, which improves the purity of L-carnitine by adding a purification process, introducing equipment such as a concentration reactor and a desalting centrifuge, but the production process will generate a large amount of waste, causing pollution to the environment. Chinese invention patent CN200810060211.9 discloses a purification and desalination process of L-carnitine, which can reduce the generation of waste in the production process by introducing an electrodialysis device to generate an ion exchange reaction, which is beneficial to energy conservation and environmental protection, but the yield of L-carnitine is not high, and it is difficult to achieve large-scale industrialization. Summary of the invention

[0004] The purpose of the present invention is to provide a method for separating and purifying L-carnitine in order to solve the above technical problems. To achieve the above purpose, the present invention provides the following technical solutions: A method for purifying L-carnitine, the method comprising the steps of: (1) Dissolve the crude L-carnitine in a mixed solvent, stir evenly, and place in a filtering device for filtering; (2) The filtrate is placed in an ion exchange resin for purification, eluted with deionized water, and freeze-dried to complete the purification of L-carnitine.

[0005] Preferably, the mixed solvent in step (1) is a mixture of ethanol and methanol in a volume ratio of 5:3.

[0006] Preferably, a composite membrane is used in the filtration device.

[0007] Preferably, the composite membrane is, from top to bottom, a microfiltration membrane, an ultrafiltration membrane, and a reverse osmosis membrane.

[0008] Preferably, the feed pressure in the filtration device is 0.2-0.3 MPa, the temperature is maintained at 10-15° C., and the feed flow rate is 35 mL / s. Beneficial Effects

[0009] The present invention effectively filters the crude product solution by using a composite membrane. The cooperation among various membranes can effectively remove various different impurities, avoiding multiple purification procedures. At the same time, by utilizing the temperature, pressure and corresponding pressure therein, effective purification can be carried out to make the purity reach more than 99%. Specific Embodiments

[0010] The present invention will be specifically described below through examples. It is necessary to point out here that the following examples are only used to further illustrate the present invention and cannot be construed as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention still fall within the protection scope of the present invention.

[0011] In addition, if there is no other description, the raw materials used are all commercially available.

[0012] A method for purifying levocarnitine, the method comprising the following steps: (1) Dissolve the crude levocarnitine in a mixed solvent, which is a mixture of ethanol and methanol in a volume ratio of 5:3. Stir evenly and place it in a filtration device for filtration. A composite membrane is used in the filtration device. The composite membrane is, from top to bottom, a microfiltration membrane, an ultrafiltration membrane, and a reverse osmosis membrane. The feeding pressure in the filtration device is 0.2 - 0.3 MPa, the temperature is maintained at 10 - 15 °C, and the flow rate of the feed liquid is 35 mL / s; (2) Put the filtrate into an ion exchange resin for purification, wash it with deionized water, and perform freeze-drying to complete the purification of levocarnitine. Example 1

[0013] A method for purifying levocarnitine, the method comprising the following steps: (1) Dissolve the crude levocarnitine in a mixed solvent, which is a mixture of ethanol and methanol in a volume ratio of 5:3. Stir evenly and place it in a filtration device for filtration. A composite membrane is used in the filtration device. The composite membrane is, from top to bottom, a microfiltration membrane, an ultrafiltration membrane, and a reverse osmosis membrane. The feeding pressure in the filtration device is 0.3 MPa, the temperature is maintained at 15 °C, and the flow rate of the feed liquid is 35 mL / s; (2) Put the filtrate into an ion exchange resin for purification, wash it with deionized water, and perform freeze-drying to complete the purification of levocarnitine.

[0014] After detection, the purity of levocarnitine is 99.5%. Example 2

[0015] A method for purifying levocarnitine, the method comprising the following steps: (1) Dissolve the crude L-carnitine in a mixed solvent, which is a mixture of ethanol and methanol in a volume ratio of 5:3. Stir evenly and place it in a filtration device for filtration. A composite membrane is used in the filtration device. The composite membrane is, from top to bottom, a microfiltration membrane, an ultrafiltration membrane, and a reverse osmosis membrane. The feed pressure in the filtration device is 0.25 MPa, the temperature is maintained at 14 °C, and the feed liquid flow rate is 35 mL / s; (2) Put the filtrate into an ion exchange resin for purification, elute with deionized water, and perform freeze-drying to complete the purification of L-carnitine.

[0016] After detection, the purity of L-carnitine is 99.8%. Example 3

[0017] A method for purifying L-carnitine, which includes the following steps: (1) Dissolve the crude L-carnitine in a mixed solvent, which is a mixture of ethanol and methanol in a volume ratio of 5:3. Stir evenly and place it in a filtration device for filtration. A composite membrane is used in the filtration device. The composite membrane is, from top to bottom, a microfiltration membrane, an ultrafiltration membrane, and a reverse osmosis membrane. The feed pressure in the filtration device is 0.23 MPa, the temperature is maintained at 13 °C, and the feed liquid flow rate is 35 mL / s; (2) Put the filtrate into an ion exchange resin for purification, elute with deionized water, and perform freeze-drying to complete the purification of L-carnitine.

[0018] After detection, the purity of L-carnitine is 99.9%. Example 4

[0019] A method for purifying L-carnitine, which includes the following steps: (1) Dissolve the crude L-carnitine in a mixed solvent, which is a mixture of ethanol and methanol in a volume ratio of 5:3. Stir evenly and place it in a filtration device for filtration. A composite membrane is used in the filtration device. The composite membrane is, from top to bottom, a microfiltration membrane, an ultrafiltration membrane, and a reverse osmosis membrane. The feed pressure in the filtration device is 0.2 MPa, the temperature is maintained at 10 °C, and the feed liquid flow rate is 35 mL / s; (2) Put the filtrate into an ion exchange resin for purification, elute with deionized water, and perform freeze-drying to complete the purification of L-carnitine.

[0020] After detection, the purity of L-carnitine is 99.7%.

[0021] It is obvious to those skilled in the art that the present invention is not limited to the details of the above-described exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, in all respects, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to embrace all changes that fall within the meaning and scope of the equivalent elements of the claims within the present invention.

Claims

1. A method for purifying L-carnitine, characterized in that, The method comprises the following steps: (1) Dissolve the crude L-carnitine in a mixed solvent, stir evenly, and place it in a filtration device for filtration; (2) Put the filtrate into an ion exchange resin for purification, elute with deionized water, and perform freeze-drying to complete the purification of L-carnitine.

2. The method for purifying L-carnitine according to claim 1, characterized in that, In the step (1), the mixed solvent is composed of ethanol and methanol mixed by volume ratio of 5:

3.

3. The method for purifying L-carnitine according to claim 1, characterized in that, A composite membrane is adopted in the filtration device.

4. The method for purifying L-carnitine according to claim 3, characterized in that, The composite membrane is successively a microfiltration membrane, an ultrafiltration membrane, and a reverse osmosis membrane from top to bottom.

5. The method for purifying L-carnitine according to claim 4, characterized in that, In the filtration device, the feeding pressure is 0.2 - 0.3 MPa, the temperature is maintained at 10 - 15 °C, and the feed liquid flow rate is 35 mL / s.