Hydroxymethionine chelate and its preparation method and application

Abstract

The application discloses a kind of hydroxyl methionine chelate and its preparation method and application, chelate can be made animal feed additive and nutrient agent, for binuclear chelate system, chelate structure A and chelate structure B include central iron ion and hydroxyl methionine ligand;The carbonyl positive coordination connection of central iron ion of chelate structure A is connected with the hydroxyl methionine ligand of chelate structure B;Preparation method includes: hydroxyl methionine is dissolved, and ligand neutralizing liquid is prepared;S2, ligand neutralizing liquid is mixed with ferrous chloride tetrahydrate solution uniformly, and reaction is complete.The hydroxyl methionine iron chelate of the application is strong in stability, can keep the biological activity of iron in complex chyme environment, can avoid absorption antagonism with manganese, copper and other trace elements, optimizes overall mineral utilization efficiency, significantly improves the absorption rate of animal, preparation condition is mild, cost is controllable, compatible with existing feed production line, and industrialization prospect is good.

Description

Technical Field

[0001] This invention relates to the field of animal feed additives, and in particular to a hydroxymethionine chelate, its preparation method, and its application. Background Technology

[0002] Iron is the most abundant trace element in the Earth's crust, mostly existing in its oxidized state or as salts. It is also widely distributed in various tissues and organs, playing a vital role in life processes.

[0003] Currently, inorganic iron salts (ferrous sulfate) are the mainstream iron nutrient additives in the animal feed additive market. However, as animal feed additives, inorganic iron salts have unavoidable negative effects and even harm—inorganic iron compounds such as FeSO4 are bound by ionic bonds, making them unstable in the digestive tract and easily dissociated. The resulting ionic iron is easily oxidized to ferric iron by other substances such as copper, and then reacts with Cl in the food. - or OH - These ions combine to form insoluble Fe(OH)3 or FeCl3 precipitates, affecting absorption. Furthermore, the dissociated iron ions readily bind with anti-nutritional substances (phytic acid, tannic acid, and soluble cellulose, etc.), forming large, poorly absorbed molecules that are excreted in feces, resulting in low digestibility and environmental harm. Additionally, due to the structural similarity between iron and manganese, iron and manganese in their ionic states share absorption and transport channels, leading to a competitive inhibitory relationship between them.

[0004] To compensate for the inadequacy of inorganic iron absorption, the following methods are generally used: ① Increasing the amount of inorganic iron added to compensate for its absorption problems; however, this method actually increases the metabolic burden on animals. ② Using organic iron compounds to replace inorganic iron salts, such as existing organic iron compounds like ferrous fumarate and ferrous glycinate. Both of these organic iron compounds exist in the form of open-chain complexes, which are not only easily dissolved in the digestive tract, but also subject to the influence of polar molecules in the environment, resulting in most iron ions still being easily dissociated. Consequently, the iron ions ultimately exist in an inorganic state, and the aforementioned defects of inorganic iron salts are not resolved. Summary of the Invention

[0005] This invention provides a stable hydroxymethionine chelate with high absorption rate, its preparation method, and its application, in order to solve the technical problems existing in the existing carbonization process mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows:

[0007] A hydroxymethionine iron chelate is a binuclear chelate system composed of chelate structure A and chelate structure B. Both chelate structure A and chelate structure B include a central iron ion and a hydroxymethionine ligand. One central iron ion is simultaneously coordinated with the hydroxy oxygen and carboxyl oxygen of two hydroxymethionine ligands to form a chelate structure with two five-membered heterocycles. The central iron ion of chelate structure A is coordinated with the carbonyl cation of the hydroxymethionine ligand of chelate structure B.

[0008] This invention forms a dual-core system (the center of A) through the interconnection of chelate structures A and B. (Coordinating with the carbonyl oxygen of the B ligand) constructs a rigid bis-five-membered heterocyclic network, significantly enhancing molecular cohesion and strengthening the stability of the molecular structure, allowing it to remain stable in feed and the digestive tract; the stable intramolecular chelate state blocks... → Oxidation pathway, avoid formation Insoluble substances are contained, ensuring the bioavailability of iron. Simultaneously, the double five-membered ring chelate bond (Fe-O carboxyl / hydroxyl) has a higher bond energy than open-chain complexes, effectively resisting the impact of the polar environment in the digestive tract and preventing the dissociation of iron ions. The chelated Fe²⁺ molecules travel through amino acid channels, avoiding contact with manganese ions (…). Competition with ion channels improves absorption efficiency.

[0009] As a further preferred embodiment of the above technical solution, the coordination number of the central iron ion in both chelate structure A and chelate structure B is 6. The central iron ion in chelate structure A is coordinated with one water molecule, and the central iron ion in chelate structure B is coordinated with two water molecules.

[0010] As a further preferred embodiment of the above technical solution, the central iron ion is a divalent iron ion.

[0011] As a further preferred embodiment of the above technical solution, the crystal space group of the hydroxymethionine chelate is P. The crystallographic parameters are shown in Table 1 below.

[0012] Table 1: Crystallographic parameters of hydroxymethionine chelates

[0013]

[0014] Based on the same technical concept, the present invention also provides a method for preparing the above-mentioned hydroxymethionine iron chelate, comprising the following steps:

[0015] S1. Dissolve hydroxymethionine to prepare a ligand neutralization solution;

[0016] S2. Mix the ligand neutralization solution with ferrous chloride tetrahydrate solution until homogeneous. After the reaction is complete, filter to obtain the solution of the hydroxymethionine iron chelate.

[0017] As a further preferred embodiment of the above technical solution, the pH of the ligand neutralization solution in S1 is 8~9.5 and the concentration is 1mol / L.

[0018] As a further preferred embodiment of the above technical solution, the molar ratio of hydroxymethionine in the ligand neutralization solution to ferrous chloride tetrahydrate in the ferrous chloride tetrahydrate solution in S2 is 10:(5~7).

[0019] As a further preferred embodiment of the above technical solution, after obtaining the solution of the hydroxymethionine iron chelate in S2, an equal volume of anhydrous ethanol is slowly added dropwise to the solution of the hydroxymethionine iron chelate. After standing and diffusion, needle-shaped transparent crystals are obtained.

[0020] Based on the same technical concept, the present invention also provides an application of the above-mentioned hydroxymethionine iron chelate, which can be used to make animal feed additives or animal nutrients.

[0021] The present invention has the following beneficial effects:

[0022] The hydroxymethionine iron chelate of this invention exhibits strong stability. Its closed chelate structure resists binding with phytic acid, tannic acid, and other substances, maintaining the bioactivity of iron in complex digesta environments. As an additive, it avoids absorption antagonism with trace elements such as manganese and copper, optimizing overall mineral utilization efficiency and significantly improving animal absorption rates. The binuclear chelate structure almost completely blocks the dissociation of iron ions in the digestive tract, significantly reducing the amount of iron added to feed. The high absorption rate directly reduces fecal iron excretion, lowering the risk of heavy metal pollution in soil / water while avoiding oxidative stress in animal liver and kidneys caused by excessive inorganic iron addition, thus reducing metabolic burden. Furthermore, the mild aqueous synthesis process (no organic solvents / high temperature and pressure required) ensures controllable costs, compatibility with existing feed production lines, and promising industrialization prospects. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the molecular structure of the hydroxymethionine iron chelate of Example 1.

[0024] Figure 2 This is a schematic diagram of the molecular arrangement inside the crystal of the hydroxymethionine iron chelate of Example 1.

[0025] Figure 3 The results of Hirshfeld surface analysis of the hydroxymethionine iron chelate in Example 1 are shown.

[0026] Figure 4 This is a fingerprint spectrum of the various forces in the hydroxymethionine iron chelate of Example 1. Detailed Implementation

[0027] The following detailed description is based on embodiments of the present invention, but the present invention can be implemented in many different ways as defined and covered by the claims.

[0028] Example 1:

[0029] like Figure 1 As shown ( Figure 1 (Fe is light red; C is gray; O is dark red; S is yellow; H is white). The hydroxymethionine iron chelate in this embodiment is a binuclear chelate system composed of chelate structure A and chelate structure B. Both chelate structure A and chelate structure B include a central iron ion (ferrous ion) and a hydroxymethionine ligand. One central iron ion simultaneously coordinates with the hydroxyl oxygen and carboxyl oxygen of two hydroxymethionine ligands to form a chelate structure with two five-membered heterocycles. The central iron ion of chelate structure A coordinates with the carbonyl cation of the hydroxymethionine ligand in chelate structure B. The coordination number of the central iron ion in both chelate structure A and chelate structure B is 6. The remaining coordination positions of the central iron ion in chelate structure A are occupied by one water molecule, while the remaining coordination positions of the central iron ion in chelate structure B are occupied by two water molecules.

[0030] The hydroxymethionine iron chelate of this embodiment was subjected to single-crystal X-ray diffraction at 200 K. The diffraction data showed that the hydroxymethionine iron chelate crystallized in P... In the space group, the central metal ion Fe(II) successfully binds to the MHA ligand via coordinate bonds. Its main crystallographic parameters and bond lengths are shown in Tables 2 and 3. Two Fe(II) molecules combine with four deprotonated MHA molecules and three water molecules to form a neutral binuclear chelate molecule. One solvent molecule bridges the coordinated water and the carbonyl oxygen of the ligand via intermolecular hydrogen bonding. Intramolecular hydrogen bonds also exist between the coordinated water and the carboxyl oxygen within the chelate molecule. Therefore, the molecular formula of the single-crystal chelate group of ferrous hydroxymethionine is [Fe2(MHA)4(H2O)3]. The four MHA molecules bind to Fe1(II) and Fe2(II) in pairs via bidentate chelate coordination sites, with the hydroxyl oxygen and the deprotonated carboxyl oxygen as coordination sites. The remaining positions in Fe1(II) are occupied by one coordinated water molecule and the carbonyl oxygen of the third MHA molecule, while the remaining positions in Fe2(II) are occupied by two coordinated water molecules. Both metal ion centers satisfy a six-coordinate octahedral configuration. The average bond length of Fe1-O (carboxyl oxygen) is 2.08 Å, the bond length of Fe1-O (oxygen in water) is 2.139(7) Å, and the octahedral distortion parameter of Fe1(II) is 77.5(10)°; the average bond length of Fe2-O (carboxyl oxygen) is 2.12 Å, the average bond length of Fe2-O (oxygen in water) is 2.07 Å, and the octahedral distortion parameter of Fe2(II) is 74.7(10)°. This indicates that the two metal centers are relatively small in terms of the degree of distortion from the regular octahedron, and the coordination geometry is relatively regular. Fe1(II) has a slightly larger octahedral distortion parameter than Fe2(II) because the carbonyl oxygen of the third MHA molecule participates in the coordination.

[0031] Supramolecular structure analysis was performed on the hydroxymethionine iron chelate of this embodiment, such as... Figure 2 As shown ( Figure 2 a is a two-dimensional layer side view. Figure 2 b is a two-dimensional top view. Figure 3 The green box in section c represents the C···HC interactions between layers. Each coordinated water molecule and the hydroxyl and carboxyl oxygen groups in the MHA ligand participate in hydrogen bond formation, connecting the molecules into a two-dimensional supramolecular layered structure. Not only are there abundant hydrogen bonds within the layers (average O···O distance approximately 2.65 Å), but the C···HC interactions between layers (average C···C distance approximately 3.40 Å) are also very strong, exhibiting strong local order.

[0032] The intermolecular interactions were further analyzed using Hirshfeld surface analysis techniques, and the results are as follows: Figure 3 and Figure 4 As shown, Figure 3 It provides an overview of intermolecular interactions ( Figure 3 a represents the ball-and-stick model of the hydroxymethionine iron chelate. Figure 3 b represents the Hirshfeld surface model of the hydroxymethionine iron chelate. Figure 3 c represents the overall fingerprint spectrum. Figure 4 The fingerprint patterns of each force are described. Figure 4 The overall fingerprint profile is shown in gray. Strong O···H contacts are present in the hydroxymethionine iron chelate, accounting for 29.5% of the total Hirshfeld surface area, indicating a strong intermolecular effect of hydrogen bonding, consistent with single-crystal structure analysis. The fingerprint also shows that due to the relatively dense molecular arrangement, H···H interactions are more prominent, accounting for 56% of the total Hirshfeld surface area. In addition, S···H interactions account for 12.2%, and the remaining 2.3% includes C···H, C···O, and other interactions.

[0033] Table 2: Crystal parameters of the hydroxymethionine iron chelate in Example 1

[0034]

[0035] Table 3: Structural parameters such as coordination bond length and bond angle of the hydroxymethionine iron chelate in Example 1

[0036]

[0037] The preparation method of the hydroxymethionine iron chelate in this embodiment includes the following steps:

[0038] S1. Dissolve 88 wt% hydroxymethionine in an appropriate amount of water and adjust its pH to approximately 9 with a 2 mol / L sodium hydroxide solution to obtain a ligand neutralization solution with a concentration of 1 mol / L.

[0039] S2. Take 10 mL of neutralization solution (10 mmol) and mix it evenly with 10 mL of ferrous chloride tetrahydrate aqueous solution (6 mmol) to obtain a yellow-green turbid liquid. Filter it through a 10 mm filter to obtain a clear green solution of ferrous hydroxymethionine chelate (MHA-Fe(II)).

[0040] S3. Place the solution of ferrous hydroxymethionine chelate in a test tube, and slowly add an equal volume of anhydrous ethanol. Allow it to stand and diffuse. After standing for three to four days, needle-like transparent crystals will grow on the test tube wall, with a yield of approximately 60%.

[0041] The hydroxymethionine iron chelate of this embodiment can be used to make animal feed additives or animal nutrients.

[0042] The following are the experimental results verifying the positive effects of the hydroxymethionine iron chelate in this embodiment as an animal feed additive:

[0043] 1.1 Test Samples

[0044] This experiment was conducted at the Xingyue Tianhua Experimental Research Center pig farm in Changsha County, Hunan Province. Fourteen 35-day-old weaned piglets weighing (8.71±0.11) kg were randomly divided into two groups, with seven replicates per group and one piglet per replicate. The control group received a basal diet supplemented with 100 mg / kg ferrous sulfate (calculated as iron), while the hydroxymethionine iron group received a basal diet supplemented with 70 mg / kg hydroxymethionine iron (calculated as iron). The experiment lasted 21 days.

[0045] 1.2 Experimental Diets

[0046] This experiment used a corn-soybean meal basal diet, with nutrient levels conforming to the "Nutritional Requirements for Swine" (GB / T39235-2020). The composition and nutrient levels of the experimental basal diet are shown in Table 4.

[0047] Table 4: Composition and nutrient levels of the experimental diets

[0048]

[0049] Note: [1] The multivitamin and mineral premix provides the following per kilogram of feed: Cu 115 mg, Zn 65 mg, Mn 40 mg, Se 0.25 mg, I 1.2 mg, Cr 0.2 mg, VA 9 500 IU, VD3 3 000 IU, VK3 3 mg, VE 24 mg, VB1 3.6 mg, VB2 7.5 mg, VB6 3 mg, VB12 0.02 mg, D-Biotin 0.12 mg, D-Pantothenic Acid 15 mg, Folic Acid 1.5 mg, Nicotinamide 30 mg.

[0050] [2] All nutritional levels are calculated values.

[0051] 1.3 Sample Collection and Measurement Indicators

[0052] 1.3.1 Growth performance

[0053] During the experiment, feed consumption and fasting body weight of pigs were recorded every week, and indicators such as average daily weight gain, average daily feed intake, and feed conversion ratio were calculated.

[0054] Note: Average daily weight gain = (final weight - initial weight) / number of days in the trial;

[0055] Average daily feed intake = Total feed intake / Number of days in the experiment;

[0056] Feed conversion ratio = average daily feed intake / average daily weight gain.

[0057] 1.3.2 Routine blood indicators

[0058] On the morning of the 7th day and the last day of the experiment, blood was collected from the anterior vena cava of each group. Blood was collected using anticoagulant tubes and non-anticoagulant tubes. The blood in the non-anticoagulant tubes was allowed to stand at room temperature for 30 minutes to separate into layers. Then, it was centrifuged at 3000 r / min for 15 minutes and the supernatant was collected for testing. The blood in the anticoagulant tubes was analyzed using a Mindray veterinary fully automated blood cell analyzer (Shenzhen Mindray Medical) to measure indicators such as white blood cells, red blood cells, hemoglobin, mean corpuscular hematocrit, red blood cell distribution width, and red blood cell volume.

[0059] 1.3.3 Iron absorption and metabolism indicators

[0060] Serum iron content, membrane iron transporter protein, ferritin, hepcidin, ceruloplasmin, transferrin, and deferrotransferrin were measured using an ELISA reader (Thermo Fisher Scientific, Germany) according to the ELISA kit instructions.

[0061] 1.3.4 Antioxidant Indicators

[0062] The activities of glutathione peroxidase (GSH-Px), malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT) in serum were measured using an ELISA reader (Thermo Fisher Scientific, Germany) according to the ELISA kit instructions. All kits were purchased from Nanjing Jiancheng Biotechnology Co., Ltd.

[0063] 1.3.5 Inflammatory Factor Indicators

[0064] Serum levels of IL-1β, IL-6, and TNF-α were measured using an ELISA reader (Thermo Fisher Scientific, Germany) according to the ELISA kit instructions. All kits were purchased from Wuhan Huamei Biotechnology Co., Ltd.

[0065] 1.4 Data Processing

[0066] Experimental data were compared between two groups using the T-test in SPSS 26.0 software. Results are expressed as mean and standard deviation. P <0.05 indicates a significant difference.

[0067] 2 Results

[0068] 2.1 Effects of hydroxymethionine iron on the growth performance of weaned piglets

[0069] As shown in Table 5 below, compared with the control group, there were no significant differences in the average daily feed intake, average daily weight gain, final weight, and feed conversion ratio in the hydroxymethionine iron group. P >0.05).

[0070] Table 5: Effects of hydroxymethionine iron on growth performance of weaned piglets

[0071]

[0072] Note: Data in the same column with the same letter or no letter above the heading indicates that the difference is not significant. P >0.05), different letters indicate significant differences ( P <0.05); the same as in the table below.

[0073] Average daily weight gain, average daily feed intake, and feed conversion ratio are important indicators for measuring animal growth performance. The results of this experiment show that the addition of hydroxymethionine iron to the diet did not have a negative impact on the growth performance of weaned piglets, while the average daily feed intake increased by 9.28%, indicating that the characteristic of hydroxymethionine iron to improve feed palatability is consistent.

[0074] Effects of 2-hydroxymethionine iron on routine blood parameters in weaned piglets

[0075] As shown in Table 6 below, compared with the control group, the hydroxymethionine iron group showed a trend of increased red blood cell count, hemoglobin, and hematocrit (<0.05). P< 0.10), but there were no significant differences in white blood cell count, mean corpuscular volume, mean hemoglobin concentration, and red blood cell distribution width. P >0.05).

[0076] Table 6: Effects of hydroxymethionine iron on routine blood parameters in weaned piglets

[0077]

[0078] Red blood cell count, hematocrit, and hemoglobin concentration are important indicators for evaluating iron status in pigs. Hematocrit refers to the percentage of whole blood volume, and its value is closely related to red blood cell count and size. Hemoglobin content can assess the body's ability to digest and absorb iron, and is also a core indicator for judging anemia. Under normal circumstances, the hemoglobin concentration of piglets is 100-120 g / L. When the hemoglobin concentration is below the lower limit of the normal range, the piglets may be anemic. This study found that compared with the control group, the hydroxymethionine iron group showed a trend of increased red blood cell count, hemoglobin, and hematocrit. Furthermore, the hemoglobin level of piglets in the control group was below 100 g / L, indicating that the piglets were in an iron-deficient state, while the hemoglobin level of piglets in the hydroxymethionine iron group was within the normal range, indicating that hydroxymethionine iron improved the hematopoietic function of piglets.

[0079] 2.3 Effects of hydroxymethionine iron on iron absorption and metabolism in weaned piglets

[0080] As shown in Table 7 below, compared with the control group, the serum iron content in the hydroxymethionine iron group was significantly increased ( P <0.01), the levels of ferritin, hepcidin, and deferrotransferrin were significantly reduced ( P <0.05).

[0081] Table 7: Effects of hydroxymethionine iron on iron absorption and metabolism in weaned piglets

[0082]

[0083] Serum iron, primarily composed of iron bound to transferrin, is a crucial indicator of the body's iron status and is clinically used to diagnose iron deficiency anemia. Hepcidin is a key hormone in iron metabolism, maintaining iron homeostasis by inhibiting intestinal iron absorption and cellular iron release. Serum ferritin is the body's main iron storage compound, while deferritin refers to transferrin that fails to bind iron. In iron deficiency anemia, the body's iron requirement increases, serum iron levels decrease, and deferritin levels increase. In this study, hydroxymethionine iron supplementation increased serum iron levels and decreased ferritin, hepcidin, and deferritin levels, indicating that the hydroxymethionine iron group has higher bioavailability than ferrous sulfate and can effectively improve the body's iron status. This may be related to the fact that hydroxymethionine iron protects iron ions through chelation, preventing the formation of insoluble compounds in the intestine, thus facilitating intestinal absorption.

[0084] Effects of 2,4-hydroxymethionine iron on antioxidant indices in weaned piglets

[0085] As shown in Table 8 below, on days 7 and 21 of the experiment, compared with the control group, the serum CAT and GSH-PX levels in the hydroxymethionine iron group were significantly increased ( P <0.05%, serum MDA levels were significantly reduced ( P <0.01), but the difference in SOD content was not significant ( P >0.05).

[0086] Table 8: Effects of hydroxymethionine iron on antioxidant indices in weaned piglets

[0087]

[0088] Free radicals in an animal's body are in a dynamic equilibrium, constantly being generated and eliminated by the antioxidant system. Iron, on the one hand, participates in the body's free radical scavenging reaction as a coenzyme for oxidoreductases; on the other hand, excess iron generates reactive oxygen species (ROS) through the Fenton reaction. CAT is an iron-containing enzyme whose main function is to participate in the metabolism of ROS. Only ROS degraded by superoxide dismutase (SOD) can be degraded by catalase into non-toxic and harmless substances such as water and oxygen. MDA is the end product of lipid peroxidation, and its content can reflect the degree of oxidative damage to the body. GSH-Px can directly scavenge oxygen free radicals, protecting the body from oxidative damage. In this invention, compared with the control group, the antioxidant enzymes GSH-Px and CAT were significantly increased in the hydroxymethionine iron group of weaned piglets, while MDA was significantly decreased, indicating that hydroxymethionine chelated iron can enhance the activity of the in vivo antioxidant enzyme system and reduce the production of lipid peroxides.

[0089] Effects of 2,5-hydroxymethionine iron on the levels of inflammatory factors in weaned piglets

[0090] As shown in Table 9 below, on days 7 and 21 of the experiment, compared with the control group, the serum levels of IL-6, IL-1β, and TNF-α in the hydroxymethionine iron group were significantly lower. P <0.01).

[0091] Table 9: Effects of hydroxymethionine iron on immune indicators in weaned piglets

[0092]

[0093] IL-1β, IL-6, and TNF-α are major pro-inflammatory factors in animals. TNF-α is mainly secreted by Th1 cells and plays an important role in cellular immune responses. IL-6 is produced by Th2 cells and plays a crucial role in regulating humoral immune responses, while IL-1β participates in the regulation of adaptive immune responses. In this invention, compared with the control group, the serum levels of IL-6, IL-1β, and TNF-α were significantly reduced in the hydroxymethionine iron group. This is related to the stable structure of hydroxymethionine chelated iron, which can reduce the release of free iron and thus reduce the inflammatory response.

[0094] The experimental results showed that feeding weaned piglets with ferrous hydroxymethionine instead of ferrous sulfate could improve iron absorption and metabolism, enhance antioxidant function, and reduce the expression of inflammatory factors.

[0095] Comparative Example 1:

[0096] The preparation method of the hydroxymethionine iron chelate in this comparative example includes the following steps:

[0097] S1. Dissolve 88 wt% hydroxymethionine in an appropriate amount of water and adjust its pH to about 7 with 2 mol / L sodium hydroxide solution to obtain a ligand neutralization solution with a concentration of 1 mol / L.

[0098] S2. Take 10 mL of neutralization solution (10 mmol) and mix it evenly with 10 mL of ferrous chloride tetrahydrate aqueous solution (6 mmol) to obtain a yellow-green turbid liquid. Filter the mixture through a 10 mm filter to obtain a yellow-green filtrate.

[0099] S3. Place the filtrate in a test tube and slowly add an equal volume of anhydrous ethanol. Allow it to stand and diffuse. After standing for several days, a red precipitate will form.

[0100] Comparative Example 2:

[0101] The preparation method of the hydroxymethionine iron chelate in this comparative example includes the following steps:

[0102] S1. Dissolve 88 wt% hydroxymethionine in an appropriate amount of water and adjust its pH to about 7 with 2 mol / L sodium hydroxide solution to obtain a ligand neutralization solution with a concentration of 1 mol / L.

[0103] S2. Take 10 mL of neutralization solution (10 mmol) and mix it evenly with 10 mL of ferrous chloride tetrahydrate aqueous solution (4 mmol) to obtain a yellow-green turbid liquid. Filter it through a 10 mm filter to obtain a clear green solution.

[0104] S3. Place the solution in a test tube and slowly add an equal volume of anhydrous ethanol. Allow it to stand and diffuse. After standing for three to four days, a thin sheet-like solid substance will grow on the test tube wall. This solid substance will rapidly oxidize in the air.

[0105] Comparative Example 3:

[0106] The preparation method of the hydroxymethionine iron chelate in this comparative example includes the following steps:

[0107] S1. Dissolve 88 wt% hydroxymethionine in an appropriate amount of water and adjust its pH to about 7 with 2 mol / L sodium hydroxide solution to obtain a ligand neutralization solution with a concentration of 1 mol / L.

[0108] S2. Take 10 mL of neutralization solution (10 mmol) and mix it evenly with 10 mL of ferrous chloride tetrahydrate aqueous solution (6 mmol) to obtain a yellow-green turbid liquid. Filter it through a 10 mm filter to obtain a clear green solution.

[0109] S3. Place the solution in a test tube and slowly add an equal volume of methanol dropwise. Allow it to stand and diffuse. After standing for several days, no product was obtained.

[0110] The above are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. For those skilled in the art, improvements and modifications obtained without departing from the inventive concept should also be considered within the scope of protection of the present invention.

[0111] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A hydroxymethionine iron chelate, characterized in that, The system comprises a binuclear chelate structure A and a chelate structure B. Both chelate structures A and B include a central iron ion and a hydroxymethionine ligand. One central iron ion simultaneously coordinates with the hydroxyl oxygen and carboxyl oxygen of each of the two hydroxymethionine ligands to form a chelate structure with two five-membered heterocycles. The central iron ion of chelate structure A coordinates with the carbonyl oxygen of the hydroxymethionine ligand in chelate structure B. The molecular formula of the hydroxymethionine chelate is Fe2(MHA)4(H2O). 3· C2H6O; the crystal space group of the hydroxymethionine chelate is P. The crystal cell parameters of the hydroxymethionine chelate are as follows: a=5.784(2)Å, b=15.016(6)Å, c=20.929(9)Å, α=85.431(13)°, β=87.655(12)°, γ=82.763(13)°. The crystal cell volume of the hydroxymethionine chelate is 1796.7(12) Å. 3 .

2. The hydroxymethionine iron chelate according to claim 1, characterized in that, The coordination number of the central iron ion in both chelate structure A and chelate structure B is 6. The central iron ion in chelate structure A is coordinated with one water molecule, while the central iron ion in chelate structure B is coordinated with two water molecules.

3. The hydroxymethionine iron chelate according to claim 1, characterized in that, The central iron ion is a divalent iron ion.

4. A method for preparing the hydroxymethionine iron chelate according to any one of claims 1-3, characterized in that, Includes the following steps: S1. Dissolve hydroxymethionine to prepare a ligand neutralization solution; S2. Mix the ligand neutralization solution with ferrous chloride tetrahydrate solution until the reaction is complete, and then filter to obtain a solution of hydroxymethionine iron chelate. Slowly add an equal volume of anhydrous ethanol to the solution of hydroxymethionine iron chelate, and after standing and diffusion, obtain needle-shaped transparent crystals.

5. The method for preparing the hydroxymethionine iron chelate according to claim 4, characterized in that, The ligand neutralization solution described in S1 has a pH of 8-9.5 and a concentration of 1 mol / L.

6. The method for preparing the hydroxymethionine iron chelate according to claim 4, characterized in that, The molar ratio of hydroxymethionine in the ligand neutralization solution to ferrous chloride tetrahydrate in the ferrous chloride tetrahydrate solution in S2 is 10:(5~7).

7. The application of the hydroxymethionine iron chelate according to any one of claims 1-3 or the hydroxymethionine iron chelate prepared by the preparation method according to any one of claims 4-6, characterized in that, The hydroxymethionine iron chelate is used to produce animal feed additives or animal nutrients.

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