CN112028785B - Preparation method of green chelating agent glutamic acid diacetic acid sodium salt - Google Patents
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- C07C227/00—Preparation of compounds containing amino and carboxyl groups bound to the same carbon skeleton
- C07C227/14—Preparation of compounds containing amino and carboxyl groups bound to the same carbon skeleton from compounds containing already amino and carboxyl groups or derivatives thereof
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Abstract
The invention relates to a preparation method of glutamic diacetic acid sodium salt, belonging to the technical field of organic synthesis. The preparation method takes sodium glutamate, glyoxylic acid and formic acid as raw materials, and after the glyoxylic acid and the sodium glutamate fully react at a certain temperature, sodium glutamate diacetate saline solution is generated under the action of the formic acid. Sodium glutamate, glyoxylic acid and formic acid used in the method are all easily available raw materials, byproducts are mainly water and carbon dioxide, highly toxic substances such as cyanide and the like are abandoned, and a large amount of wastewater and toxic byproducts are not generated; chloroacetic acid is also abandoned as a raw material, so that the influence of chloride ions in the product on certain use scenes is prevented, and the method is green, economical, environment-friendly and easy for large-scale industrial production.
Description
Technical Field
The invention belongs to the technical field of organic synthesis, and provides a preparation method for synthesizing a green chelating agent glutamic acid diacetic acid sodium salt by taking sodium glutamate and glyoxylic acid as raw materials.
Background
Glutamic acid diacetic acid sodium salt (GLDA) is a green chelating agent widely used in the market at present. The glutamic diacetic acid sodium salt has strong metal chelating capacity, and has similar performance to nitrilotriacetic acid (NTA), ethylene Diamine Tetraacetic Acid (EDTA), sodium tripolyphosphate (STTP) and the like. Among them, NTA is a suspicious carcinogen which has been prohibited by Europe and America, EDTA is not easily biodegradable, STTP contains phosphorus, and is easy to cause eutrophication of rivers and lakes, and the three substances all cause harm to the environment and human body. GLDA is undoubtedly the best choice, given the requirement of phosphorus-free, and considering the negative effects of EDTA and NTA on the environment and human body. The glutamic diacetic acid sodium salt has good biodegradability, the biodegradation rate in 28 days in OECD test exceeds 80%, and the glutamic diacetic acid sodium salt belongs to a harmless product in the latest classification of GHS. Sodium glutamate (monosodium glutamate) is used as a main raw material, more than half of carbon atoms are derived from natural carbon atoms, and the sodium glutamate (monosodium glutamate) is a sustainable development product.
Japanese patent JP1987039554A mentions a method for producing alkyl amino acids using sodium cyanide; european patent EP0913461A1 mentions the use of sodium glutamate diacetate and its related chelating agents, primarily for use in detergents; european patent EP1004571 discloses a method for preparing high-purity glutamic acid diacetic acid sodium salt, which improves the use value of the product; chinese patent CN101784513B proposes a method for preparing glutamic acid diacetic acid sodium salt by using sodium glutamate, hydrocyanic acid and formaldehyde, but the use of highly toxic substances such as cyanide and the like is still not avoided, and the generated toxic wastewater is difficult to treat; chinese patent CN109369427A proposes a method for preparing glutamic acid diacetic acid sodium salt by using sodium glutamate and chloroacetic acid as raw materials, but the product contains a large amount of chloride ions, which not only affects the product quality, but also causes damage to some use equipment.
Disclosure of Invention
The invention aims to provide a green method for preparing glutamic acid diacetic acid sodium salt, which takes sodium glutamate, glyoxylic acid and formic acid as raw materials, and generates a glutamic acid diacetic acid sodium salt aqueous solution under the action of formic acid after the glyoxylic acid and the sodium glutamate fully react at a certain temperature. Sodium glutamate, glyoxylic acid and formic acid used in the method are all easily available raw materials, byproducts are mainly water and carbon dioxide, highly toxic substances such as cyanide and the like are eliminated, and a large amount of wastewater and toxic byproducts are not generated; chloroacetic acid is also abandoned as a raw material, so that the influence of chloride ions in the product on certain use scenes is prevented, and the method is green, economical, environment-friendly and easy for large-scale industrial production.
In order to achieve the purpose, the invention adopts the technical scheme that:
a preparation method of a green chelating agent glutamic acid diacetic acid sodium salt comprises the following steps:
(1) Adding the metered sodium glutamate and deionized water into a reaction kettle, stirring and mixing uniformly at room temperature;
(2) Respectively filling glyoxylic acid, formic acid and liquid alkali into a dripping device for later use;
(3) Heating the reaction kettle in the step (1) to a specified temperature, starting to dropwise add glyoxylic acid, and continuing to keep the temperature for a period of time after dropwise addition is finished;
(4) After the heat preservation is finished, formic acid is dripped, negative pressure concentration is kept after the dripping is finished, and reflux heat preservation is carried out;
(5) Adding liquid alkali to adjust the pH value;
(6) Cooling to 40-60 ℃ to obtain the finished product of the sodium glutamate diacetate aqueous solution.
Further, the mass ratio of the sodium glutamate to the deionized water in the step (1) is 1. Furthermore, the mass ratio of the sodium glutamate to the deionized water in the step (1) is 1.
Further, the molar ratio of the sodium glutamate to the glyoxylic acid and the formic acid in the step (2) is 1.5-5.0. Furthermore, the molar ratio of the sodium glutamate to the glyoxylic acid and the formic acid in the step (2) is 1.5-3.0.
Further, the mass fraction of the glyoxylic acid is 40-50%, and the mass fraction of the formic acid is 80-90%.
Further, the specified temperature in the step (3) is 50-95 ℃, the dripping time of the glyoxylic acid is 0.5-8 hours, and the heat preservation time is 0.5-5 hours.
Further, the dripping temperature in the step (4) is 50-95 ℃, the dripping time of the formic acid is 0.5-8 hours, the negative pressure range is 0-minus 0.01Mpa, and the reflux heat preservation time is 2-12 hours.
Further, the mass fraction of the liquid caustic soda in the step (5) is 30-40%, and the pH value is adjusted to be 4-12.
The invention uses sodium glutamate, glyoxylic acid and formic acid as raw materials, uses glyoxylic acid to replace cyanide, chloroacetonitrile and chloroacetic acid in the traditional method, and obtains a green chelating agent, namely glutamic acid diacetic acid sodium salt through condensation reduction, wherein the specific reaction is as follows:
compared with the prior art, the invention has the beneficial effects that:
1. sodium glutamate, glyoxylic acid and formic acid are used as raw materials, so that the use of highly toxic substances is avoided, the product quality is improved, toxic by-products and chloride ions are not contained in the product, and the atom utilization rate is greatly improved.
2. Vacuum concentration is added, the reaction concentration is kept in the reaction process, the reaction efficiency is improved, and the effective content is increased.
3. The effective content in the product is greatly improved to more than 45 percent while the by-products are reduced.
4. The reaction condition is simple and mild, green, safe and environment-friendly, and is easy for industrial mass production.
Detailed Description
The present invention is described in detail below by way of examples, which should be construed as being merely illustrative, and not limitative of the remainder of the disclosure.
Example 1
936g of monosodium glutamate monohydrate and 702g of deionized water are added into a reaction kettle, stirred and mixed evenly at room temperature, and 1727g of glyoxylic acid (mass fraction is 45%), 530g of formic acid (mass fraction is 88%) and 980g of sodium hydroxide solution (mass fraction is 32%) are respectively filled into a dropping device for standby. Heating the reaction system to 90 ℃, starting to dropwise add glyoxylic acid, controlling the dropwise adding speed to keep the reaction temperature at 90 ℃, finishing dropwise adding within 1.5 hours, and preserving heat for 1 hour after dropwise adding. After the heat preservation, the reaction system is heated to 95 ℃, formic acid is dripped, the dripping speed is controlled to keep the reaction temperature at 95 ℃, the dripping is finished within 2 hours, after the dripping is finished, the heat preservation is carried out for 2 hours under the negative pressure condition of-0.01 Mpa, and the excess water in the reaction is removed. And (3) beginning to dropwise add liquid caustic soda, controlling the temperature to be less than 95 ℃, adjusting the pH to 9, cooling and discharging. 3850g of yellow transparent sodium glutamate diacetate solution is obtained, the effective content is 43 percent, and the product yield is 94 percent.
Example 2
936g of monosodium glutamate monohydrate and 936g of deionized water are added into a reaction kettle, stirred and mixed uniformly at room temperature, and 2056g of glyoxylic acid (with the mass fraction of 45%), 445g of formic acid (with the mass fraction of 88%) and 1080g of sodium hydroxide solution (with the mass fraction of 32%) are respectively filled into a dropping device for standby. Heating the reaction system to 60 ℃, starting to dropwise add glyoxylic acid, controlling the dropwise adding speed to keep the reaction temperature at 60 ℃, finishing dropwise adding within 2 hours, and keeping the temperature for 1 hour after dropwise adding. After the heat preservation, the reaction system is heated to 75 ℃, formic acid is dripped, the dripping speed is controlled, the reaction temperature is kept at 75 ℃, the dripping is finished within 2 hours, after the dripping is finished, the heat preservation is carried out for 3 hours under the negative pressure condition of-0.01 Mpa, and the excess water in the reaction is removed. And (3) beginning to dropwise add liquid caustic soda, controlling the temperature to be less than 75 ℃, adjusting the pH to 9, cooling and discharging. 4034g of yellow transparent sodium glutamate diacetate solution is obtained, the effective content is 38 percent, and the product yield is 87 percent.
Example 3
936g of monosodium glutamate monohydrate and 1158g of deionized water are added into a reaction kettle, stirred and mixed evenly at room temperature, and 1727g of glyoxylic acid (mass fraction is 45%), 530g of formic acid (mass fraction is 88%) and 1030g of sodium hydroxide solution (mass fraction is 32%) are respectively filled into a dropping device for standby. Heating the reaction system to 65 ℃, starting to dropwise add glyoxylic acid, controlling the dropwise adding speed to keep the reaction temperature at 65 ℃, finishing dropwise adding after 4 hours, and keeping the temperature for 1 hour after the dropwise adding is finished. After the heat preservation, the reaction system is heated to 95 ℃, formic acid is dripped, the dripping speed is controlled to keep the reaction temperature at 95 ℃, the dripping is finished within 3 hours, after the dripping is finished, the heat preservation is carried out for 4 hours under the negative pressure condition of-0.01 Mpa, and the excess water in the reaction is removed. Dropping liquid alkali, controlling the temperature to be less than 50 ℃, adjusting the pH value to 10, cooling and discharging. 4164g of yellow transparent glutamic acid disodium diacetate solution with an effective content of 43 percent and a product yield of 93 percent are obtained.
Example 4
936g of monosodium glutamate monohydrate and 1872g of deionized water are added into a reaction kettle, stirred and mixed uniformly at room temperature, and 1891g of glyoxylic acid (mass fraction of 45%), 630g of formic acid (mass fraction of 88%) and 1130g of sodium hydroxide solution (mass fraction of 32%) are respectively filled into a dripping device for standby. Heating the reaction system to 50 ℃, starting to dropwise add glyoxylic acid, controlling the dropwise adding speed to keep the reaction temperature at 50 ℃, finishing dropwise adding within 5 hours, and keeping the temperature for 1 hour after dropwise adding. After the heat preservation, the reaction system is heated to 75 ℃, formic acid is dripped, the dripping speed is controlled, the reaction temperature is kept at 75 ℃, the dripping is finished within 2 hours, after the dripping is finished, the heat preservation is carried out for 5 hours under the negative pressure condition of-0.01 Mpa, and the excess water in the reaction is removed. And (3) beginning to dropwise add liquid caustic soda, controlling the temperature to be less than 55 ℃, adjusting the pH to 11, cooling and discharging. 4337g of yellow transparent glutamic acid disodium diacetate solution is obtained, the effective content is 45 percent, and the product yield is 96 percent.
The product of this example was subjected to nuclear magnetic testing, and the resulting nuclear magnetic data: 1 H NMR(400MHz,D 2 O)(ppm)δ3.18-2.93(m,5H),2.17-1.97(m,2H),1.78-1.62(m，2H)。
example 5
936g of monosodium glutamate monohydrate and 1200g of deionized water are added into a reaction kettle, stirred and mixed uniformly at room temperature, and 1727g of glyoxylic acid (mass fraction of 45%), 730g of formic acid (mass fraction of 88%) and 1565g of sodium hydroxide solution (mass fraction of 32%) are respectively filled into a dripping device for standby. Heating the reaction system to 85 ℃, starting to dropwise add glyoxylic acid, controlling the dropwise adding speed to keep the reaction temperature at 85 ℃, finishing dropwise adding within 2.5 hours, and preserving the temperature for 2 hours after dropwise adding. And (3) dropwise adding formic acid after the heat preservation is finished, controlling the dropwise adding speed to keep the reaction temperature at 85 ℃, finishing dropwise adding within 1.5 hours, preserving the heat for 5 hours under the negative pressure condition of-0.01 Mpa after the dropwise adding is finished, and removing the excessive water in the reaction. And (3) beginning to dropwise add liquid caustic soda, controlling the temperature to be less than 50 ℃, adjusting the pH to 11, cooling and discharging. 4253g of yellow transparent glutamic acid sodium diacetate solution is obtained, the effective content is 44 percent, and the product yield is 95 percent.
Example 6
936g of monosodium glutamate monohydrate and 500g of deionized water are added into a reaction kettle, stirred and mixed uniformly at room temperature, and 2200g of glyoxylic acid (with the mass fraction of 45%), 730g of formic acid (with the mass fraction of 88%) and 1875g of sodium hydroxide solution (with the mass fraction of 32%) are respectively filled into a dripping device for standby. Heating the reaction system to 70 ℃, starting to dropwise add glyoxylic acid, controlling the dropwise adding speed to keep the reaction temperature at 70 ℃, finishing dropwise adding within 4.5 hours, and preserving the temperature for 1 hour after dropwise adding. After the heat preservation, the reaction system is heated to 85 ℃, formic acid is dripped, the dripping speed is controlled, the reaction temperature is kept at 85 ℃, the dripping is finished within 1.5 hours, after the dripping is finished, the heat preservation is carried out for 5 hours under the negative pressure condition of-0.01 Mpa, and the excess water in the reaction is removed. And (3) beginning to dropwise add liquid caustic soda, controlling the temperature to be less than 55 ℃, adjusting the pH to 11, cooling and discharging. 4550g of yellow transparent glutamic acid disodium diacetate solution is obtained, the effective content is 46 percent, and the product yield is 97 percent.
Example 7
The calcium sequestering performance of the samples of examples 1-6 was determined:
the experiments were carried out according to the method for determining the calcium sequestration value provided in GB/T26324-2010 hydroxyethylidenediphosphonic acid. The experimental conditions are as follows: about 1.5g of the sample (to the nearest 0.01 g) was weighed into a 250ml beaker and 100ml of deionized water was added. The beaker is placed on an electromagnetic stirrer, a stirrer is placed in the beaker, and stirring is started. The samples were mixed well and 10ml of sodium carbonate solution was added. The electrode was inserted into the solution, sodium hydroxide solution was added dropwise to a pH of 11, and water was added to 150ml. Titrating with calcium standard solution, and simultaneously dropwise adding sodium hydroxide solution to maintain the pH value at 11. The end point is that turbidity does not disappear when the solution appears.
Calcium sequestration value (as CaCO) 3 In ω) and values in mg/g: ω = ρ V (M) 1 /M 2 )/m
[ remarks: ρ, the value of the actual solution of the calcium standard solution in milligrams per milliliter (mg/ml); v, number of volumes of calcium standard solution consumed in titration, in milliliters (ml); m 1 The molar mass of calcium carbonate is given in grams per mole (g/mol) (M) 1 ＝100.09)；M 2 The value of the molar mass of calcium is given in grams per mole (g/mol) (M) 2 = 40.08); m, the numerical value of the mass of the sample, in grams (g).
The test results are shown in table 1.
Table 1 comparative results of calcium chelating properties of samples of examples
| Numbering | Effective content% | Calcium sequestration value (CaCO) 3 ,mg/g) |
| Example 1 | 43 | 229 |
| Example 2 | 38 | 215 |
| Example 3 | 43 | 231 |
| Example 4 | 45 | 245 |
| Example 5 | 44 | 240 |
| Example 6 | 46 | 247 |
| Outsourcing sample | 40 | 219 |
The test results in table 1 show that the sodium glutamate diacetate product prepared by the method has higher effective content, and the calcium chelating performance is superior to or equivalent to that of an outsourcing sample.
Note: the method for measuring the effective content of the sample comprises the following steps:
weighing about 0.5g of sample (accurate to 0.2 mg), placing the sample in a 250ml beaker, adding 50ml of chloroacetic acid-sodium acetate buffer solution with the pH value of 10ml and approximately equal to 3, adding 2 drops of 2 percent (mass percent) of titanium indicator, placing the beaker containing the sample on an electromagnetic stirrer, stirring uniformly, and titrating to bright green by using 0.1mol/L ferric trichloride standard titration solution while stirring, thus obtaining the end point.
Effective content in w 1 In% and w is calculated according to the formula 1 ＝V·C·M/1000m×100％
[ remarks: v, the value of the volume of ferric trichloride standard solution consumed in milliliters (ml); c, an accurate value of the actual concentration of the ferric trichloride standard titration solution, wherein the unit is mole per liter (ml/L); m, the number of molar masses of tetrasodium glutamate diacetate in grams per mole (g/mol) (M = 351); m, the numerical value of the mass of the sample, in grams (g).
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (7)
1. A preparation method of glutamic diacetic acid sodium salt as a green chelating agent is characterized by comprising the following steps:
(1) Adding the metered sodium glutamate and deionized water into a reaction kettle, stirring and mixing uniformly at room temperature;
(2) Respectively filling glyoxylic acid, formic acid and liquid alkali into a dripping device for later use;
(3) Heating the reaction kettle in the step (1) to a specified temperature, starting to dropwise add glyoxylic acid, and continuing to keep the temperature for a period of time after dropwise addition is finished;
(4) Dripping formic acid after the heat preservation is finished, keeping negative pressure concentration after the dripping is finished, and performing reflux heat preservation;
(5) Adding liquid alkali to adjust the pH value;
(6) And cooling to 40-60 ℃ to obtain the sodium glutamate diacetate aqueous solution.
2. The method for preparing glutamic diacetic acid sodium salt as a green chelating agent of claim 1, wherein the mass ratio of sodium glutamate to deionized water in the step (1) is 1.
3. The method for preparing glutamic acid diacetic acid sodium salt as a green chelating agent according to claim 1, wherein the molar ratio of sodium glutamate to glyoxylic acid and formic acid in the step (2) is 1.5 to 5.0.
4. The preparation method of the green chelating agent glutamic acid diacetic acid sodium salt according to claim 1, wherein the mass fraction of the glyoxylic acid is 40 to 50 percent, and the mass fraction of the formic acid is 80 to 90 percent.
5. The method for preparing the green chelating agent sodium glutamate diacetate according to the claim 1, wherein the temperature specified in the step (3) is 50 to 95 ℃, the dripping time of glyoxylic acid is 0.5 to 8 hours, and the holding time is 0.5 to 5 hours.
6. The preparation method of the green chelating agent glutamic acid diacetic acid sodium salt as the claim 1, wherein the dropping temperature in the step (4) is 50 to 95 ℃, the dropping time of formic acid is 0.5 to 8 hours, the negative pressure range is 0 to-0.01 MPa, and the reflux insulation time is 2 to 12 hours.
7. The preparation method of the green chelating agent glutamic acid diacetic acid sodium salt according to claim 1, wherein the mass fraction of the liquid alkali in the step (5) is 30 to 40%, and the pH value is adjusted to be 4 to 12.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2009024519A1 (en) * | 2007-08-17 | 2009-02-26 | Akzo Nobel N.V. | Glutamic acid n,n-diacetic amide, glutamic acid n-acetic amide n-acetonitrile, alkali metal salts thereof, process to prepare them and their use |
| WO2011113822A1 (en) * | 2010-03-18 | 2011-09-22 | Basf Se | Method for producing aminocarboxylates low in by-product |
| CN105924365A (en) * | 2016-05-19 | 2016-09-07 | 河北诚信有限责任公司 | Method for continuously synthesizing tetrasodium glutamate diacetate through tubular reactor |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2009024519A1 (en) * | 2007-08-17 | 2009-02-26 | Akzo Nobel N.V. | Glutamic acid n,n-diacetic amide, glutamic acid n-acetic amide n-acetonitrile, alkali metal salts thereof, process to prepare them and their use |
| WO2011113822A1 (en) * | 2010-03-18 | 2011-09-22 | Basf Se | Method for producing aminocarboxylates low in by-product |
| CN105924365A (en) * | 2016-05-19 | 2016-09-07 | 河北诚信有限责任公司 | Method for continuously synthesizing tetrasodium glutamate diacetate through tubular reactor |
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