CN114394948B - Recycling method of panthenol mother liquor - Google Patents
Recycling method of panthenol mother liquor Download PDFInfo
- Publication number
- CN114394948B CN114394948B CN202111647239.4A CN202111647239A CN114394948B CN 114394948 B CN114394948 B CN 114394948B CN 202111647239 A CN202111647239 A CN 202111647239A CN 114394948 B CN114394948 B CN 114394948B
- Authority
- CN
- China
- Prior art keywords
- calcium
- reaction
- panthenol
- aminopropanol
- filter cake
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D307/00—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom
- C07D307/02—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings
- C07D307/26—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having one double bond between ring members or between a ring member and a non-ring member
- C07D307/30—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having one double bond between ring members or between a ring member and a non-ring member with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
- C07D307/32—Oxygen atoms
- C07D307/33—Oxygen atoms in position 2, the oxygen atom being in its keto or unsubstituted enol form
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C213/00—Preparation of compounds containing amino and hydroxy, amino and etherified hydroxy or amino and esterified hydroxy groups bound to the same carbon skeleton
- C07C213/02—Preparation of compounds containing amino and hydroxy, amino and etherified hydroxy or amino and esterified hydroxy groups bound to the same carbon skeleton by reactions involving the formation of amino groups from compounds containing hydroxy groups or etherified or esterified hydroxy groups
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C213/00—Preparation of compounds containing amino and hydroxy, amino and etherified hydroxy or amino and esterified hydroxy groups bound to the same carbon skeleton
- C07C213/10—Separation; Purification; Stabilisation; Use of additives
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention provides a method for recycling panthenol mother liquor, which comprises the following steps: evaporating the solvent in the panthenol mother liquor to dryness, adding water to redissolve the solute component, regulating the pH value to be alkaline by using calcium hydroxide, carrying out heat preservation reaction at 80-85 ℃, cooling and precipitating after the reaction is finished, and separating to obtain a pantoic acid calcium filter cake and a filtrate containing 3-aminopropanol; mixing the pantoic acid calcium filter cake with sulfuric acid, reacting at 80-85 ℃ under heat preservation, adding an alkaline calcium-containing compound into the reaction liquid after the reaction is finished to precipitate calcium ions, and separating to obtain a calcium sulfate filter cake and a filtrate containing pantoic acid lactone. The method provided by the invention can recover the pantolactone and the 3-aminopropanol in the panthenol mother liquor with higher yield, is simple to operate, has low cost and is suitable for industrial application.
Description
Technical Field
The invention belongs to the technical field of chemical industry, and particularly relates to a method for recycling panthenol mother liquor.
Background
Panthenol includes three forms of the mixed isomer (DL-form), the dextrorotatory isomer (D-form) and the levorotatory isomer (L-form), wherein only the dextrorotatory isomer has biological activity and the levorotatory isomer has no biological activity. DL-panthenol is a precursor of vitamin B5, is a white powdery solid, has slight special smell and is easy to absorb moisture. DL-panthenol is readily soluble in water, ethanol, methanol and propylene glycol, in chloroform and ether, slightly soluble in glycerol, insoluble in vegetable oils, mineral oils and fats.
DL-panthenol is an equivalent of pantothenic acid, is a precursor of coenzyme A, can be converted into pantothenic acid when entering a human body, and further synthesizes coenzyme A, promotes metabolism of human proteins, fats and saccharides, protects mucous membranes and luster of the skin surface, and prevents diseases. Panthenol can also be used as nutritional supplement, and can be widely applied in medicine, food and cosmetic industries.
At present, the industrial production method of DL-panthenol generally comprises the steps of firstly synthesizing panthenol in a solution, and then cooling and crystallizing to separate out panthenol crystals. However, the crystallization method cannot completely separate out the panthenol, a part of panthenol can remain in the mother liquor, and a small amount of unreacted raw materials and auxiliary materials are left, so that if the mother liquor is discarded, not only can the resource waste be caused, but also the environment can be polluted. Therefore, the components in the mother liquor need to be recycled.
Disclosure of Invention
Aiming at the defects existing in the prior art, the invention aims to provide a method for recycling panthenol mother liquor. The method successfully realizes the recovery of pantolactone and 3-aminopropanol from the panthenol mother liquor, and has higher yield.
To achieve the purpose, the invention adopts the following technical scheme:
a method for recycling panthenol mother liquor comprises the following steps:
(1) Evaporating the solvent in the panthenol mother liquor to dryness, adding water for redissolving the solute component, regulating the pH to be alkaline by using calcium hydroxide, carrying out heat preservation reaction under the conditions of 80-85 ℃ (such as 80 ℃, 81 ℃, 82 ℃, 83 ℃, 84 ℃ or 85 ℃ and the like), cooling and precipitating after the reaction is finished, and separating to obtain a pantoic acid calcium filter cake and a filtrate containing 3-aminopropanol;
(2) Mixing the calcium pantothenate filter cake with sulfuric acid, reacting at 80-85deg.C (such as 80deg.C, 82deg.C, 83deg.C, 84deg.C or 85deg.C, etc.), adding alkaline calcium-containing compound to the reaction solution after the reaction to precipitate calcium ions, and separating to obtain calcium sulfate filter cake and filtrate containing pantolactone.
In the art, panthenol is generally synthesized by taking pantolactone and 3-aminopropanol as raw materials and reacting the raw materials in a solvent, the panthenol crystals are separated out from the reaction solution by cooling and crystallizing, and the filtrate obtained after solid-liquid separation is panthenol mother liquor which contains unreacted raw materials pantolactone and 3-aminopropanol, uncrystallized panthenol and the solvent (such as methanol, ethanol and the like).
In the step (1), calcium hydroxide is used for hydrolyzing panthenol into pantolactone and 3-aminopropanol, and meanwhile, pantolactone is converted into calcium pantoate precipitate with low solubility; in step (2), calcium pantoate is converted into pantolactone by sulfuric acid, and the excess sulfuric acid is converted into calcium sulfate precipitate by an alkaline calcium-containing compound. The method realizes the recovery of pantolactone and 3-aminopropanol from the panthenol mother liquor.
In some embodiments of the invention, the mass ratio of water to solute components in step (1) is 3-5:1; for example, it may be 3:1, 3.2:1, 3.5:1, 3.8:1, 4:1, 4.2:1, 4.5:1, 4.8:1, or 5:1, etc.
In some embodiments of the invention, the pH is adjusted to 10-13 in step (1); for example, 10, 10.5, 11, 11.5, 12, 12.5, 13, etc. are possible.
In some embodiments of the invention, the time of the reaction in step (1) is 1 to 3 hours; for example, 1h, 1.2h, 1.5h, 1.8h, 2h, 2.2h, 2.5h, 2.8h, 3h, or the like may be used.
In some embodiments of the invention, the temperature of the reduced temperature precipitate in step (1) is 20-30 ℃; for example, it may be 20 ℃, 22 ℃, 23 ℃, 25 ℃, 26 ℃, 28 ℃, 30 ℃, or the like.
In some embodiments of the present invention, after the calcium pantoate filter cake in step (2) is mixed with sulfuric acid, the pH of the resulting mixture is 1 to 1.5; for example, 1, 1.1, 1.2, 1.3, 1.4, or 1.5, etc.
In some embodiments of the invention, the time of the reaction in step (2) is 1 to 3 hours; for example, 1h, 1.2h, 1.5h, 1.8h, 2h, 2.2h, 2.5h, 2.8h, 3h, or the like may be used.
In some embodiments of the invention, after the reaction in step (2) is completed, cooling to 20-30 ℃; for example, it may be 20 ℃, 22 ℃, 23 ℃, 25 ℃, 26 ℃, 28 ℃, 30 ℃, or the like.
In some embodiments of the invention, in step (2) an alkaline calcium-containing compound is added to the reaction solution to a pH of 6.5-7; for example, 6.5, 6.6, 6.7, 6.8, 6.9, or 7, etc.
In some embodiments of the invention, the basic calcium-containing compound is selected from one or more of calcium hydroxide, calcium oxide, calcium carbonate, and calcium bicarbonate.
In some embodiments of the invention, the method further comprises: and evaporating the filtrate containing the 3-aminopropanol to dryness, and rectifying to obtain the 3-aminopropanol.
In some embodiments of the invention, the method further comprises: evaporating the filtrate containing the pantolactone to dryness to obtain the pantolactone.
In some embodiments of the invention, the method comprises the steps of:
(1) Evaporating the solvent in the panthenol mother liquor to dryness, adding water to redissolve the solute component, regulating the pH to 10-13 by using calcium hydroxide, carrying out heat preservation reaction for 1-3h at 80-85 ℃, cooling to 20-30 ℃ after the reaction is finished, precipitating, and separating to obtain a pantoic acid calcium filter cake and a filtrate containing 3-aminopropanol;
(2) Mixing the pantoic acid calcium filter cake with sulfuric acid, keeping the pH of the obtained mixed solution at 1-1.5, reacting at 80-85 ℃ for 1-3h, cooling to 20-30 ℃ after the reaction, regulating the pH of the reaction solution to 6.5-7 by using calcium hydroxide to precipitate calcium ions, and separating to obtain a calcium sulfate filter cake and a filtrate containing pantoic acid lactone;
evaporating the filtrate containing pantolactone to obtain pantolactone;
and evaporating the filtrate containing the 3-aminopropanol to dryness and rectifying to obtain the 3-aminopropanol.
Compared with the prior art, the invention has the following beneficial effects:
according to the method, firstly, calcium hydroxide is used for hydrolyzing panthenol into pantolactone and 3-aminopropanol, meanwhile, pantolactone is converted into calcium pantoate precipitate with low solubility, then sulfuric acid is used for converting calcium pantoate into pantolactone, and redundant sulfuric acid is converted into calcium sulfate precipitate by using an alkaline calcium-containing compound, so that the recovery of pantolactone and 3-aminopropanol from panthenol mother liquor is successfully realized, the yield of pantolactone reaches more than 90%, and the yield of 3-aminopropanol reaches more than 81%.
Detailed Description
The technical scheme of the invention is further described by the following specific embodiments. It should be apparent to those skilled in the art that the detailed description is merely provided to aid in understanding the invention and should not be taken as limiting the invention in any way.
The ingredients of the panthenol mother liquor used in the examples of the invention are as follows:
DL-pantolactone 0.3wt%, 3-aminopropanol 0.2wt%, DL-panthenol 5wt% except methanol as solvent.
Example 1
The embodiment provides a method for recycling panthenol mother liquor, which comprises the following steps:
(1) Evaporating methanol in DL-panthenol mother liquor to dryness, recovering, taking 200g of solute component, adding 600g of water for re-dissolving, adjusting pH to 11 with calcium hydroxide, reacting at 83 ℃ for 2 hours under heat preservation, cooling to 25 ℃ after the reaction is finished for precipitation, and filtering to obtain a pantoic acid calcium filter cake and a filtrate containing 3-aminopropanol;
(2) Adding sulfuric acid solution into the calcium pantoate filter cake, keeping the pH of the obtained mixed solution at 1, reacting for 2 hours at 83 ℃, cooling to 25 ℃ after the reaction, regulating the pH of the reaction solution to 6.7 by using calcium hydroxide to precipitate calcium ions, and filtering to obtain a calcium sulfate filter cake and a filtrate containing pantoate lactone;
evaporating the filtrate containing pantolactone to dryness to obtain 122.3g of pantolactone;
the filtrate containing 3-aminopropanol was evaporated to dryness and distilled to obtain 63.1g of 3-aminopropanol.
Example 2
The embodiment provides a method for recycling panthenol mother liquor, which comprises the following steps:
(1) Evaporating methanol in DL-panthenol mother liquor to dryness, recovering, taking 200g of solute component, adding 1000g of water for re-dissolving, regulating pH to 10 by using calcium hydroxide, carrying out heat preservation reaction for 1h at 85 ℃, cooling to 20 ℃ after the reaction is finished, precipitating, and filtering to obtain a pantoic acid calcium filter cake and a filtrate containing 3-aminopropanol;
(2) Adding sulfuric acid solution into the calcium pantothenate filter cake, keeping the pH of the obtained mixed solution at 1.3, reacting at 85 ℃ for 1h, cooling to 20 ℃ after the reaction, regulating the pH of the reaction solution to 6.5 by using calcium hydroxide to precipitate calcium ions, and filtering to obtain a calcium sulfate filter cake and a filtrate containing pantolactone;
evaporating the filtrate containing pantolactone to dryness to obtain 121.1g of pantolactone;
the filtrate containing 3-aminopropanol was evaporated to dryness and was rectified to give 62.8g of 3-aminopropanol.
Example 3
The embodiment provides a method for recycling panthenol mother liquor, which comprises the following steps:
(1) Evaporating methanol in DL-panthenol mother liquor to dryness, recovering, taking 200g of solute component, adding 800g of water for re-dissolving, regulating pH to 13 by using calcium hydroxide, carrying out heat preservation reaction for 3 hours at 80 ℃, cooling to 30 ℃ after the reaction is finished, precipitating, and filtering to obtain a pantoic acid calcium filter cake and a filtrate containing 3-aminopropanol;
(2) Adding sulfuric acid solution into the calcium pantoate filter cake, keeping the pH of the obtained mixed solution at 1.5, reacting for 3 hours at 80 ℃, cooling to 30 ℃ after the reaction, regulating the pH of the reaction solution to 7 by using calcium hydroxide to precipitate calcium ions, and filtering to obtain a calcium sulfate filter cake and a filtrate containing pantoate lactone;
evaporating the filtrate containing pantolactone to dryness to obtain 116.8g of pantolactone;
the filtrate containing 3-aminopropanol was evaporated to dryness and 60.9g of 3-aminopropanol was obtained after rectification.
Example 4
The present example provides a method for recycling panthenol mother liquor, which differs from example 1 only in that in step (1), calcium hydroxide is used to adjust the pH to 9.
Example 5
The present example provides a method for recycling panthenol mother liquor, which differs from example 1 only in that the pH of the mixed solution after adding sulfuric acid solution in step (2) is 2.5.
Comparative example 1
The comparative example provides a method for recycling panthenol mother liquor, which comprises the following specific steps:
(1) Evaporating methanol in DL-panthenol mother liquor to dryness, recovering, taking 200g of solute component, adding 800g of water for re-dissolving, dripping sulfuric acid to adjust the pH value to 1, then carrying out heat preservation and stirring at 80 ℃ for l h, cooling to 30 ℃, adding sodium hydroxide to adjust the pH value to 5, and decolorizing and filtering by using active carbon to obtain decolorized filtrate;
(2) Adding ethyl acetate into the obtained filtrate, extracting for 3 times, sharing 450mL of ethyl acetate, respectively collecting ethyl acetate phase and water phase, combining the ethyl acetate phase, and concentrating to obtain 102.3g of pantolactone;
(3) Regulating the pH of the water phase obtained in the step (2) to the isoelectric point of 3-aminopropanol by using a sodium hydroxide solution, concentrating under reduced pressure until the water content is 30%, cooling to 0 ℃ for crystallization, and filtering to respectively recover crystalline sodium sulfate and filtrate containing 3-aminopropanol;
(4) The filtrate of 3-aminopropanol was dehydrated under reduced pressure, followed by rectification to give 56.3g of 3-aminopropanol.
The purities of the pantolactone and 3-aminopropanol recovered in the above examples and comparative examples were measured by liquid chromatography and gas chromatography, respectively, and the yields (initial mass based on the total mass of the component contained in the DL-panthenol mother liquor and the component which can be produced by complete hydrolysis of DL-panthenol) were calculated, and the results are shown in table 1 below:
TABLE 1
As can be seen from Table 1, the method provided by the invention successfully realizes the recovery of pantolactone and 3-aminopropanol from the panthenol mother liquor, the yield of pantolactone reaches more than 90%, and the yield of 3-aminopropanol reaches more than 81%.
Among them, example 4 resulted in incomplete decomposition of panthenol due to a lower pH in step (1) compared to example 1, and thus the purity and yield of the obtained pantolactone and 3-aminopropanol were reduced. Example 5 the reaction of calcium pantoate with sulfuric acid was insufficient due to the higher pH in step (2), and the yield and purity of the pantolactone obtained were reduced.
The method of comparative example 1 is insufficient in panthenol hydrolysis, the yields of pantolactone and 3-aminopropanol are low, and the method of comparative example 1 requires a large amount of organic solvent, and is complex in operation, not environment-friendly, and large in pantolactone loss.
While the invention has been described in detail in the foregoing general description, embodiments and experiments, it will be apparent to those skilled in the art that modifications and improvements can be made thereto. Accordingly, such modifications or improvements may be made without departing from the spirit of the invention and are intended to be within the scope of the invention as claimed.
Claims (11)
1. The method for recycling the panthenol mother liquor is characterized by comprising the following steps of:
(1) Evaporating the solvent in the panthenol mother liquor to dryness, adding water to redissolve the solute component, regulating the pH value to be alkaline by using calcium hydroxide, carrying out heat preservation reaction at 80-85 ℃, cooling and precipitating after the reaction is finished, and separating to obtain a pantoic acid calcium filter cake and a filtrate containing 3-aminopropanol;
(2) Mixing the calcium pantoate filter cake with sulfuric acid, carrying out heat preservation reaction at 80-85 ℃, adding an alkaline calcium-containing compound into the reaction liquid after the reaction is finished to precipitate calcium ions, and separating to obtain a calcium sulfate filter cake and a filtrate containing pantolactone;
wherein, in the step (1), the pH is adjusted to 10-13;
and (3) mixing the calcium pantoate filter cake in the step (2) with sulfuric acid, wherein the pH value of the obtained mixed solution is 1-1.5.
2. The method of claim 1, wherein the mass ratio of water to solute components in step (1) is 3-5:1.
3. The method according to claim 1, wherein the reaction time in step (1) is 1 to 3 hours.
4. A process according to any one of claims 1 to 3, wherein the temperature of the reduced temperature precipitate in step (1) is 20 to 30 ℃.
5. A process according to any one of claims 1 to 3, wherein the reaction in step (2) is carried out for a period of time of from 1 to 3 hours.
6. A process according to any one of claims 1 to 3, wherein after the reaction in step (2) is completed, the temperature is reduced to 20 to 30 ℃.
7. A method according to any one of claims 1-3, characterized in that in step (2) an alkaline calcium-containing compound is added to the reaction solution to a pH of 6.5-7.
8. The method of claim 7, wherein the basic calcium-containing compound is selected from one or more of calcium hydroxide, calcium oxide, calcium carbonate, and calcium bicarbonate.
9. A method according to any one of claims 1-3, wherein the method further comprises: and evaporating the filtrate containing the 3-aminopropanol to dryness, and rectifying to obtain the 3-aminopropanol.
10. A method according to any one of claims 1-3, wherein the method further comprises: evaporating the filtrate containing the pantolactone to dryness to obtain the pantolactone.
11. A method according to any one of claims 1-3, characterized in that the method comprises the steps of:
(1) Evaporating the solvent in the panthenol mother liquor to dryness, adding water to redissolve the solute component, regulating the pH to 10-13 by using calcium hydroxide, carrying out heat preservation reaction for 1-3h at 80-85 ℃, cooling to 20-30 ℃ after the reaction is finished, precipitating, and separating to obtain a pantoic acid calcium filter cake and a filtrate containing 3-aminopropanol;
(2) Mixing the pantoic acid calcium filter cake with sulfuric acid, keeping the pH of the obtained mixed solution at 1-1.5, reacting at 80-85 ℃ for 1-3h, cooling to 20-30 ℃ after the reaction, regulating the pH of the reaction solution to 6.5-7 by using calcium hydroxide to precipitate calcium ions, and separating to obtain a calcium sulfate filter cake and a filtrate containing pantoic acid lactone;
evaporating the filtrate containing pantolactone to obtain pantolactone;
and evaporating the filtrate containing the 3-aminopropanol to dryness and rectifying to obtain the 3-aminopropanol.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111647239.4A CN114394948B (en) | 2021-12-29 | 2021-12-29 | Recycling method of panthenol mother liquor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111647239.4A CN114394948B (en) | 2021-12-29 | 2021-12-29 | Recycling method of panthenol mother liquor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114394948A CN114394948A (en) | 2022-04-26 |
| CN114394948B true CN114394948B (en) | 2023-06-06 |
Family
ID=81228215
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111647239.4A Active CN114394948B (en) | 2021-12-29 | 2021-12-29 | Recycling method of panthenol mother liquor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114394948B (en) |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111748591B (en) * | 2019-03-29 | 2022-04-01 | 安徽华恒生物科技股份有限公司 | Production method of D-pantoic acid lactone |
| CN110845307B (en) * | 2019-11-28 | 2021-09-17 | 安徽泰格生物科技有限公司 | Method for recovering D-calcium pantothenate mother liquor |
| CN111499602B (en) * | 2020-05-14 | 2022-06-07 | 安徽泰格生物科技有限公司 | Method for extracting D-pantolactone from DL-pantolactone split liquid by calcium salt method |
| CN111484463A (en) * | 2020-05-22 | 2020-08-04 | 安徽安力肽生物科技有限公司 | Method for recycling panthenol mother liquor |
| CN112209819A (en) * | 2020-09-27 | 2021-01-12 | 安徽泰格生物科技有限公司 | Preparation method of D-pantoic acid calcium |
-
2021
- 2021-12-29 CN CN202111647239.4A patent/CN114394948B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN114394948A (en) | 2022-04-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP1005562B1 (en) | Succinic acid production and purification | |
| CN110845307A (en) | Method for recovering D-calcium pantothenate mother liquor | |
| CN112174845B (en) | Preparation method of D-panthenol | |
| CN111689908B (en) | Post-treatment method for synthesizing 4, 6-dihydroxypyrimidine | |
| CN114409570B (en) | Preparation method of chloridized L-carnitine nitrile | |
| CN111518056A (en) | Treatment and utilization method of acesulfame potassium crystallization waste liquid | |
| CN103420881A (en) | Novel method for preparing medicinal despun hydroxyl methionine calcium | |
| CN109134287B (en) | Purification method of byproduct sodium chloride in betaine or betaine hydrochloride production | |
| CN114394948B (en) | Recycling method of panthenol mother liquor | |
| CN112457181B (en) | Synthesis method of D-calcium pantothenate | |
| KR20100122773A (en) | Process for separating and purifying succinic acid from fermentation broth | |
| CN112645357B (en) | Post-treatment method of sodium sulfate mother liquor | |
| CN111961077B (en) | Preparation method of beta sodium glycerophosphate containing crystal water | |
| CN101555239A (en) | Method for extracting vitamin C and 2-keto-L-gulonic acid from vitamin C mother liquor | |
| CN104355990A (en) | Method for recycling and mechanically using L- (+) -tartaric acid in D-ethyl ester production | |
| CN113121375A (en) | Method for preparing food-grade and feed-grade magnesium glycinate and implementation device thereof | |
| CN110606863B (en) | Preparation method of N-acetylneuraminic acid dihydrate | |
| CN113105352A (en) | Method for preparing food-grade and feed-grade zinc glycinate and implementation device thereof | |
| CN1130627A (en) | Process for preparing sodium (or potassium) L-ascorbate | |
| CN109836344B (en) | Method for producing glycine by organic solvent | |
| CN111517976A (en) | Synthesis process of vitamin B5 | |
| CN103087018A (en) | Preparation method of erythorbic acid | |
| CN110903252B (en) | Preparation method of 4, 6-dihydroxypyrimidine | |
| CN113735727B (en) | Preparation method of raceme ketoisoleucine calcium and intermediate thereof | |
| CN115650868B (en) | Preparation method of L-carnitine |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |