Pre-nursing feed additive and preparation method thereof

Abstract

The invention belongs to the field of organic synthesis, and particularly relates to a pre-nursing feed additive and a preparation method thereof, the additive is DL-methionine complex zinc, and the reaction steps are as follows: DL-methionine and a zinc source are taken as raw materials, and a chelation reaction is performed in the presence of an ionic liquid catalyst to generate the DL-methionine complex zinc. The metal ion liquid catalyst adopted by the invention can improve the reaction activity of the zinc source, so that the reaction can be efficiently and quickly carried out, an additional alkali catalyst is not needed, the reaction temperature is low, the reaction time is short, the post-treatment operation is simple, the production cost is greatly reduced, and the method conforms to the green chemical industry trend and is suitable for industrial production.

Description

Technical Field

[0001] The invention belongs to the field of organic synthesis, and in particular relates to a pre-nursery feed additive and a preparation method thereof. Background Art

[0002] Since the discovery and preparation of chelates by the chemical community in the early 17th century, the research and application of chelates have been greatly developed in many industries. In the 1970s, metal amino acid chelates began to be used in animal nutrition, and their application fields are becoming more and more extensive. The American Official Feed Management Association defines the concept of amino acid chelates as follows: Amino acid metal element chelates refer to products formed by the reaction of 1 mol of metal ions in soluble metal salts with 1 to 3 mol of amino acids, and the molecular weight of the generated chelates generally does not exceed 800, which is conducive to the complete transportation and absorption of trace elements in the form of chelates, and can effectively release metal ions when needed. Amino acid metal chelates have the characteristics of stable chemical structure, high biological efficacy, can enhance immunity, improve disease resistance, and are green and environmentally friendly.

[0003] As one of the important trace element additives, DL-methionine complex zinc chelate reacts inorganic zinc with DL-methionine to produce a chelate with a ring structure. Because the molecular structure of amino acid zinc is closer to the action form of Zn in the body, it is a trace element supplement close to the natural form of the animal body. As a new feed additive, it can improve animal growth, reproduction and health, and has the functions of promoting the rapid proliferation of tongue mucosal taste bud cells, regulating appetite, inhibiting certain harmful bacteria in the intestine, prolonging the residence time of food in the digestive tract, and improving the secretion function of the digestive system and the activity of enzymes in tissue cells. The absorption rate of DL-methionine complex zinc chelate in animals is 2-4 times that of ordinary inorganic zinc, and methionine itself is also a high-level nutrient. Animals can absorb zinc while absorbing methionine, which is of great biological value.

[0004] Pre-nursery feed is specially designed for newly weaned piglets to meet their nutritional needs for growth and development. The feed during this period should not only be easy to digest and absorb, but also provide enough energy, protein and essential amino acids to help piglets pass the weaning stress period smoothly, reduce the occurrence of diseases and improve the survival rate. Therefore, DL-methionine complex zinc chelate is widely used in pre-nursery feed.

[0005] CN 111978222A relates to a method for preparing a feed additive DL-methionine complex zinc. The method comprises heating a methionine aqueous solution to 60-80°C, maintaining a constant temperature, adding a zinc salt, stirring, adding a methionine metal salt and a corresponding carbonate aqueous solution to adjust the pH, heating to 60-110°C, reacting for 0.5-1.0 hours, and then filtering and washing with normal temperature water to obtain a methionine zinc product. The method produces a large amount of by-products, resulting in a large amount of wastewater discharge, difficulty in treatment, and high treatment cost. Considering the current national environmental protection policy, it is urgent to find a new synthesis method to reduce the wastewater discharged during the production process of methionine zinc chelate and solve the pollution problem from the source.

[0006] CN101914049A discloses the preparation of zinc methionine using methionine and zinc oxide as raw materials and formic acid or acetic acid as an initiator, and obtaining a granular zinc methionine product by separation, drying and sieving. The product obtained by the method is easy to dry after separation, does not need to be crushed, and avoids dust, but the reaction can only occur under the action of an initiator, the reaction time is long, and the zinc content in the obtained zinc methionine is low.

[0007] CN111094301A discloses a method for preparing a methionine-metal chelate, wherein methionine and Ca(OH)2 are mixed, and a metal nitrate or a metal chloride is added to the mixture to generate the methionine-metal chelate. Although this method can improve the recovery rate of the methionine-metal chelate and prevent the generation of insoluble by-product salts, the method generates by-products Ca(NO3)2 or CaCl2, produces metal waste, and has complex process steps and high production costs, which is not conducive to industrial production.

[0008] Based on this, there is an urgent need to develop a method for preparing DL-methionine complexed zinc, a pre-nursery feed additive, which has mild reaction conditions, is green and environmentally friendly, and is suitable for industrial production. Summary of the invention

[0009] In view of the problems existing in the prior art, the purpose of the present invention is to provide a preparation method of DL-methionine complexed zinc as a pre-nursery feed additive, so as to solve the problems existing in the prior art such as environmental pollution, harsh reaction conditions, low chelation rate, and unsuitability for industrial production. The present invention is achieved by the following technical solutions:

[0010] A method for preparing a pre-nursery feed additive, wherein the additive is DL-methionine complexed zinc, and the preparation method comprises the following steps:

[0011] Using DL-methionine and zinc source as raw materials, a chelation reaction occurs in the presence of an ionic liquid catalyst to generate a DL-methionine complexed zinc pre-nursery feed additive;

[0012] Wherein, the zinc source is selected from one or more of zinc hydroxide, zinc oxide, zinc nitrate, zinc sulfate and zinc carbonate;

[0013] The structural formula of the ionic liquid catalyst is:

[0014] In some embodiments, the reaction solvent is selected from one or more of water, methanol, ethanol, and isopropanol.

[0015] In some embodiments, the reaction solvent is preferably water.

[0016] In some embodiments, the zinc source is preferably zinc hydroxide or zinc oxide.

[0017] In some embodiments, the molar ratio of DL-methionine to zinc source is (2.0-2.5):1; the molar ratio of DL-methionine to ionic liquid catalyst is 1:(0.005-0.015).

[0018] In some embodiments, after the reaction is completed, the reaction solution is cooled to 10-15° C. and then filtered, and the filter cake is washed with hot water. The obtained solid is then vacuum dried to obtain DL-methionine complexed zinc.

[0019] In some embodiments, the filtrate after filtration is distilled under reduced pressure to remove the residual solvent, and the residue is vacuum dried to obtain an ionic liquid catalyst, which can be further recycled.

[0020] In some embodiments, the reaction temperature is 20-50° C., and the reaction time is 20-40 min.

[0021] In some embodiments, the preparation method comprises the following steps:

[0022] DL-methionine, zinc hydroxide and water are added into a reactor, and then an ionic liquid catalyst is slowly added, and the temperature is raised to 35°C and stirred for reaction for 30 minutes. After the reaction, the reaction liquid is cooled to 15°C and then filtered, and the filter cake is washed with hot water, and then the obtained solid is vacuum dried at 110°C to obtain DL-methionine complexed zinc chelate.

[0023] On the other hand, the present invention also protects the pre-nursery feed additive prepared by the above preparation method.

[0024] The present invention has achieved the following beneficial effects:

[0025] 1) The metal ion liquid catalyst used in the present invention can improve the reaction activity of the zinc source, and then can react with methionine to form methionine zinc chelate with high yield and chelation rate. In addition, compared with the prior art, the present invention does not produce inorganic salt wastewater, is green and environmentally friendly, and is suitable for industrial production.

[0026] 2) The reaction conditions of the present invention are mild, the reaction temperature is low and the reaction time is short.

[0027] 3) The filtrate after filtration in the present invention is subjected to reduced pressure distillation to remove the residual solvent, and the residue is vacuum dried to obtain an ionic liquid catalyst, which can be continuously recycled. DETAILED DESCRIPTION

[0028] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] The endpoints and any values ​​of the scope described in the present invention are not limited to the precise scope or value, and these scopes or values ​​should be understood to include values ​​close to these scopes or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered as specifically disclosed in this article.

[0030] Preparation Example 1: Preparation of Metal Ion Liquid Catalyst

[0031] Step 1: Preparation of ionic liquid intermediates

[0032]

[0033] Under nitrogen protection, N,N'-carbonyldiimidazole (0.1mol) and 1-chlorobutane (0.2mol) were added to the reactor, followed by acetonitrile (200mL) and ethanol (30ml), and the temperature was raised to 70°C and stirred under reflux for 12h. After the reaction was completed, the solution was cooled to room temperature, and petroleum ether (200mL) and ethyl acetate (100mL) were added to the solution. A brown viscous liquid was precipitated, and the mixture was extracted by a separatory funnel, and the residual solvent was removed by rotary evaporation. Finally, the collected viscous liquid was vacuum dried to obtain an ionic liquid intermediate.

[0034] Step 2: Preparation of metal ion liquid catalyst

[0035]

[0036] Under nitrogen protection, the ionic liquid intermediate (0.1 mol) prepared in step 1 was added to the reactor, followed by ZnCl2·2H2O (0.2 mol), and the temperature was raised to 85°C and stirred for reaction for 8 hours. After the reaction, the solvent was removed by rotary evaporation, and the mixture was vacuum dried at 110°C for 10 hours to obtain a metal ionic liquid catalyst with a yield of 92.0%.

[0037] 1 H NMR (400MHz, DMSO-d6) δ7.61(s,2H),7.17(s,2H),6.86(s,2H),3.97-3.92(m,4H),1.66-1.59(m,4H),1.24-1.19(m,4H),0.91-0.85(m,6H).

[0038] Example 1

[0039] DL-methionine (30.0 g, 0.2 mol), zinc hydroxide (10.0 g, 0.1 mol) and water (200 mL) were added to the reactor, and then the ionic liquid catalyst obtained in Preparation Example 1 was slowly added. (0.01 mol), heated to 35°C and stirred for reaction for 30 min. After the reaction, the reaction solution was cooled to 15°C and filtered, and the filter cake was washed with hot water. The obtained solid was then vacuum dried at 110°C to obtain DL-methionine complexed zinc chelate, with a yield of 97.1% and a chelation rate of 99.5%.

[0040] The filtrate after filtration is subjected to reduced pressure distillation to remove the residual solvent, and the residue is vacuum dried to obtain an ionic liquid catalyst, which can be continuously recycled.

[0041] By comparison, the HPLC retention time of the product of this example is consistent with that of the DL-methionine complex zinc chelate standard.

[0042] Example 2

[0043] DL-methionine (30.0 g, 0.2 mol), zinc oxide (8.1 g, 0.1 mol) and water (200 mL) were added to the reactor, and then the ionic liquid catalyst obtained in Preparation Example 1 was slowly added. (0.005 mol), heated to 30°C and stirred for 40 minutes. After the reaction, the reaction solution was cooled to 15°C and filtered, and the filter cake was washed with hot water. The obtained solid was then vacuum dried at 110°C to obtain DL-methionine complexed zinc chelate, with a yield of 96.3% and a chelation rate of 99.2%.

[0044] The filtrate after filtration is subjected to reduced pressure distillation to remove the residual solvent, and the residue is vacuum dried to obtain an ionic liquid catalyst, which can be continuously recycled.

[0045] By comparison, the HPLC retention time of the product of this example is consistent with that of the DL-methionine complex zinc chelate standard.

[0046] Example 3

[0047] DL-methionine (3.0 kg, 20.1 mol), zinc hydroxide (1.0 kg, 10.0 mol) and water (20 L) were added to the reactor, and then the ionic liquid catalyst obtained in Preparation Example 1 was slowly added. (1.0 mol), heated to 40°C and stirred for reaction for 35 min. After the reaction, the reaction solution was cooled to 15°C and filtered, and the filter cake was washed with hot water. The obtained solid was then vacuum dried at 110°C to obtain DL-methionine complexed zinc chelate, with a yield of 96.0% and a chelation rate of 99.1%.

[0048] The filtrate after filtration is subjected to reduced pressure distillation to remove the residual solvent, and the residue is vacuum dried to obtain an ionic liquid catalyst, which can be continuously recycled.

[0049] By comparison, the HPLC retention time of the product of this example is consistent with that of the DL-methionine complex zinc chelate standard.

[0050] The above embodiments are merely examples for clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A method for preparing a pre-nursery feed additive, characterized in that: The additive is DL-methionine complexed zinc, and its preparation method comprises the following steps: Using DL-methionine and zinc source as raw materials, a chelation reaction occurs in the presence of an ionic liquid catalyst to generate a DL-methionine complexed zinc pre-nursery feed additive; Wherein, the zinc source is selected from one or more of zinc hydroxide, zinc oxide, zinc nitrate, zinc sulfate and zinc carbonate; The structural formula of the ionic liquid catalyst is:

2. The preparation method according to claim 1, characterized in that: The reaction solvent is selected from one or more of water, methanol, ethanol and isopropanol.

3. The preparation method according to claim 1, characterized in that: The zinc source is zinc hydroxide or zinc oxide.

4. The preparation method according to claim 1, characterized in that: The molar ratio of the DL-methionine to the zinc source is (2.0-2.5):1; the molar ratio of the DL-methionine to the ionic liquid catalyst is 1:(0.005-0.015).

5. The preparation method according to claim 1, characterized in that: After the reaction is completed, the reaction solution is cooled to 10-15° C. and then filtered, and the filter cake is washed with hot water. The obtained solid is then vacuum dried to obtain DL-methionine complexed zinc.

6. The preparation method according to claim 5, characterized in that: The filtrate after filtration is distilled under reduced pressure to remove the residual solvent, and the residue is vacuum dried to obtain an ionic liquid catalyst, which can be continuously recycled.

7. The preparation method according to claim 1, characterized in that: The reaction temperature is 20-50°C and the reaction time is 20-40 minutes.

8. The preparation method according to claim 1, characterized in that: The steps include: DL-methionine, zinc hydroxide and water are added into a reactor, and then an ionic liquid catalyst is slowly added, and the temperature is raised to 35°C and stirred for reaction for 30 minutes. After the reaction, the reaction liquid is cooled to 15°C and then filtered, and the filter cake is washed with hot water, and then the obtained solid is vacuum dried at 110°C to obtain DL-methionine complexed zinc chelate.

9. The pre-nursery feed additive prepared according to the preparation method according to any one of claims 1 to 8.

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