Preparation method of feed additive DL-methionine complex copper

Abstract

The invention belongs to the field of organic synthesis, and particularly relates to a preparation method of a feed additive DL-methionine complex copper, which comprises the following reaction steps: taking DL-methionine and a copper source as raw materials, and carrying out chelation reaction in the presence of an ionic liquid catalyst to generate the DL-methionine complex copper. The metal ion liquid catalyst adopted by the invention can improve the reaction activity of the copper 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 method for preparing DL-methionine complex copper as a feed additive. 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 chelates refer to products formed by the reaction of 1 mol of metal ions in soluble metal salts with 1 to 3 mol (optimally 2 mol) of amino acids, which are combined by coordinated covalent bonds. The molecular weight of the generated chelate is generally not more than 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.

[0003] Amino acid metal chelates have the characteristics of stable chemical structure, high biological efficacy, enhanced immunity, improved disease resistance, and green environmental protection. DL-methionine complexed copper can alleviate the competition and antagonism between trace elements through pinocytosis absorption, which not only greatly improves the absorption and utilization rate of copper ions and the absorption of other trace elements, but also methionine as a carrier is safe and harmless. Therefore, adding it to feed will not destroy various types of vitamins, nor will it catalyze the oxidation reaction of oils and fats in feed, and at the same time it can improve the quality of feed.

[0004] CN111051317A discloses a method for preparing a methionine-metal chelate, wherein methionine (i.e., methionine) is first mixed with calcium hydroxide, and then a metal chloride such as copper chloride is added to the mixture to generate a methionine copper chelate. The method utilizes the difference in solubility between the methionine copper chelate and the methionine calcium chelate to displace the more insoluble methionine copper chelate. However, the method generates a byproduct of calcium chloride, i.e., it also generates unnecessary inorganic salts, and there is also the problem that the mother liquor cannot be applied and the subsequent environmental protection treatment cost is too high.

[0005] CN111978221A discloses a method for preparing a feed additive DL-methionine copper complex. The method is to heat a methionine aqueous solution to 60-80°C, maintain a constant temperature, add a copper salt, stir, add a methionine metal salt and a corresponding carbonate aqueous solution to adjust the pH, heat to 60-110°C, react for 0.5-1.0 hours, and then filter and wash with normal temperature water to obtain a methionine copper product. This method is the most common method, which has many by-products and leads to a large amount of wastewater discharge, difficult 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 copper chelate and solve the pollution problem from the source. The existing green, environmentally friendly and economical preparation method of methionine copper chelate has little improvement or the reaction is cumbersome and harsh, and it is difficult to promote industrialization.

[0006] CN115724778B discloses a method for preparing a methionine copper chelate. The method uses methionine and copper hydroxide as raw materials, and generates a methionine copper chelate by reaction in water and in the presence of a catalyst, wherein the catalyst is selected from a water-soluble divalent copper salt. Preferably, the water-soluble divalent copper salt is selected from a combination of one or more of copper sulfate, copper chloride, copper nitrate, copper acetate and copper formate. However, the method has a high reaction temperature, a long reaction time, and a low chelation rate of the product, and is not suitable for industrial production.

[0007] Based on this, there is an urgent need to develop a method for preparing DL-methionine complexed copper with mild reaction conditions, green and environmentally friendly, and suitable for industrial production. Summary of the invention

[0008] In view of the problems existing in the prior art, the purpose of the present invention is to provide a method for preparing DL-methionine copper complexed feed additive 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 through the following technical solutions:

[0009] A method for preparing a feed additive DL-methionine complexed copper comprises the following steps:

[0010] Using DL-methionine and a copper source as raw materials, a chelating reaction occurs in the presence of an ionic liquid catalyst to generate DL-methionine complexed copper;

[0011] Wherein, the copper source is selected from one or more of copper hydroxide, copper oxide and copper carbonate;

[0012] The structural formula of the ionic liquid catalyst is:

[0013] In some embodiments, the reaction solvent is selected from one or more of water, methanol, ethanol, and isopropanol.

[0014] In some embodiments, the reaction solvent is water.

[0015] In some embodiments, the copper source is copper hydroxide or copper oxide.

[0016] In some embodiments, the molar ratio of the DL-methionine to the copper 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).

[0017] 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 copper.

[0018] 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.

[0019] In some embodiments, the reaction temperature is 25-45° C., and the reaction time is 20-40 min.

[0020] In some embodiments, the method preferably comprises the steps of:

[0021] DL-methionine, copper hydroxide and water were added into the reactor, and then the ionic liquid catalyst was slowly added, and the temperature was raised to 40°C and stirred for reaction for 20 minutes. After the reaction, the reaction liquid was cooled to 15°C and filtered, and the filter cake was washed with hot water at 90°C, and then the obtained solid was vacuum dried at 100°C for 5 hours to obtain DL-methionine copper complex chelate.

[0022] The present invention has achieved the following beneficial effects:

[0023] 1) The metal ion liquid catalyst used in the present invention can improve the reaction activity of the copper source, and then can react with methionine to form methionine copper 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.

[0024] 2) The reaction conditions of the present invention are mild, the reaction temperature is low and the reaction time is short.

[0025] 2) 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

[0026] 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.

[0027] 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.

[0028] Preparation Example 1: Preparation of Metal Ion Liquid Catalyst

[0029] Step 1: Preparation of ionic liquid intermediates

[0030]

[0031] Under nitrogen protection, N,N'-carbonyldiimidazole (0.1mol) and 1-chlorobutane (0.2mol) were added to the reactor, and then acetonitrile (200mL) and ethanol (30ml) were added in sequence, and the temperature was raised to 70°C and refluxed with stirring for 12h. After the reaction was completed, it 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 placed in a vacuum drying oven for 10 hours to obtain an ionic liquid intermediate with a yield of 36.2%.

[0032] Step 2: Preparation of metal ion liquid catalyst

[0033]

[0034] Under nitrogen protection, the ionic liquid intermediate (0.1 mol) prepared in step 1 was added to the reactor, followed by CuCl2·2H2O (0.2 mol), and the temperature was raised to 90°C and stirred for reaction for 6 hours. After the reaction, the solvent was removed by rotary evaporation, and the mixture was vacuum dried at 100°C for 12 hours to obtain a metal ionic liquid catalyst with a yield of 93.1%.

[0035] 1H NMR (400MHz, DMSO-d6) δ7.62(s,2H),7.17(s,2H),6.88(s,2H),3.96-3.91(s,4H),1.66-1.58(s,4H),1.23-1.17(s,4H),0.92-0.84(s,6H).

[0036] Example 1

[0037] DL-methionine (30.0 g, 0.2 mol), copper hydroxide (9.8 g, 0.1 mol) and water (300 mL) were added to the reactor, and then the ionic liquid catalyst obtained in Preparation Example 1 was slowly added. (0.01mol), heated to 40°C and stirred for reaction for 20min. After the reaction, the reaction solution was cooled to 15°C and filtered, and the filter cake was washed with 90°C hot water, and then the obtained solid was vacuum dried at 100°C for 5h to obtain DL-methionine complexed copper chelate, with a yield of 98.7% and a chelation rate of 99.6%.

[0038] 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.

[0039] By comparison, the HPLC retention time of the product of this example is consistent with that of the DL-methionine complex copper standard.

[0040] Example 2

[0041] DL-methionine (30.0 g, 0.2 mol), CuO (8.0 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. (0.005 mol), heated to 35°C and stirred for reaction for 30 min. After the reaction, the reaction solution was cooled to 10°C and filtered, and the filter cake was washed with 90°C hot water, and then the obtained solid was vacuum dried at 100°C for 5 h to obtain DL-methionine complex copper chelate, with a yield of 96.9% and a chelation rate of 99.4%.

[0042] 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.

[0043] By comparison, the HPLC retention time of the product of this example is consistent with that of the DL-methionine complex copper standard.

[0044] Example 3 (Scaled-up production)

[0045] DL-methionine (3.0 kg, 20.1 mol), copper hydroxide (0.98 kg, 10.0 mol) and water (30 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 30 min. After the reaction, the reaction solution was cooled to 15°C and filtered, and the filter cake was washed with 90°C hot water, and then the obtained solid was vacuum dried at 100°C for 5 h to obtain DL-methionine complexed copper chelate, with a yield of 97.0% and a chelation rate of 99.3%.

[0046] 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.

[0047] By comparison, the HPLC retention time of the product of this example is consistent with that of the DL-methionine complex copper standard.

[0048] 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 feed additive DL-methionine complexed copper, comprising the following steps: Using DL-methionine and a copper source as raw materials, a chelating reaction occurs in the presence of an ionic liquid catalyst to generate DL-methionine complexed copper; in, The copper source is selected from one or more of copper hydroxide, copper oxide and copper 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 2, characterized in that: The reaction solvent is water.

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

5. The preparation method according to claim 1, characterized in that: The molar ratio of the DL-methionine to the copper 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).

6. 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 copper.

7. The preparation method according to claim 6, 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.

8. The preparation method according to claim 1, characterized in that: The reaction temperature is 25-45°C and the reaction time is 20-40 minutes.

9. The preparation method according to claim 1, characterized in that: The steps include: DL-methionine, copper hydroxide and water were added into the reactor, and then the ionic liquid catalyst was slowly added, and the temperature was raised to 40°C and stirred for reaction for 20 minutes. After the reaction, the reaction liquid was cooled to 15°C and filtered, and the filter cake was washed with hot water at 90°C, and then the obtained solid was vacuum dried at 100°C for 5 hours to obtain DL-methionine copper complex chelate.

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