Production process of ferrous fumarate

Abstract

The invention belongs to the technical field of organic synthesis, and relates to a production process of ferrous fumarate. According to the method, maleic anhydride and high-purity ferrous oxide are taken as starting raw materials, ferrous maleate is obtained through a catalytic reaction of a phase transfer catalyst under the protection of nitrogen, and (E)-2-butenedioic acid ferrite, namely ferrous fumarate, is obtained through transformation isomerization of the ferrous maleate. According to the method, sulfate is not generated, the problem of waste salt generation is solved, a reducing agent is not used, additional waste salt is not used, the problems of high impurity content, excessive heavy metal, insufficient product purity, high-COD wastewater and the like are solved, the reaction time is greatly shortened, the oxidation reaction of ferrous iron is effectively restrained, the reaction temperature is reduced to 45-50 DEG C from 90 DEG C or above, energy consumption is saved, and the production cost is reduced.

Description

Technical Field

[0001] The invention relates to a production process of ferrous fumarate and belongs to the technical field of organic synthesis. Background Art

[0002] Ferrous fumarate is a divalent iron preparation and a safe and efficient organic nutritional iron supplement. It has a high iron content, is stable, and has a rapid onset of action. It is widely used in the fields of medicine, health products, and feed additives.

[0003] The traditional process of ferrous fumarate mostly adopts the route of fumaric acid, alkali and ferrous sulfate. First, fumaric acid is salified to form fumarate, and then it reacts with ferrous sulfate solution to chelate and form ferrous fumarate. Patents CN1680255A, CN102370055A, CN110845325A and CN107473956A all use fumaric acid, alkali and ferrous sulfate as raw materials. Ferrous sulfate can be an aqueous solution of ferrous sulfate heptahydrate, ferrous sulfate monohydrate or prepared by the reaction of iron powder and sulfuric acid. It has been reported that iron powder, sodium bisulfite, thiourea dioxide and the like are added as reducing agents. Sodium carbonate, ammonia water and liquid alkali are generally used as alkali. The main components of wastewater in this traditional method are sodium sulfate, fumaric acid and ferrous sulfate. The wastewater has the problems of high COD, high sodium sulfate salinity and difficulty in treatment. The reaction temperature of the traditional process is generally above 90°C. Heating for too long not only consumes a lot of energy, but also easily leads to the oxidation of divalent iron ions. In addition, due to the incomplete reaction of iron powder, iron and sulfate residues are left. The quality of ferrous fumarate products is unstable, which affects the use of downstream feed additives. Summary of the invention

[0004] The invention provides a ferrous fumarate production process. The ferrous fumarate produced by the invention has high purity, low heavy metal impurity content, and low salt content in waste water. The invention is an ideal and practical ferrous fumarate synthesis process.

[0005] The present invention adopts the following technical solutions:

[0006] Under nitrogen protection, maleic anhydride and high-purity ferrous oxide are used as starting materials, and a phase transfer catalyst is used to catalyze the reaction to obtain ferrous maleate, and the ferrous maleate is transformed and isomerized to obtain (E)-2-butenedioic acid ferrous salt, namely ferrous fumarate.

[0007] The specific reaction process is:

[0008]

[0009] The specific steps are:

[0010] (1) under nitrogen protection, maleic anhydride is added to water, stirred to dissolve, and then a phase transfer catalyst is added, the temperature is raised, and high-purity ferrous oxide is added in batches. After the addition is completed, the pH is adjusted, the reaction is stirred, the temperature is lowered, and the filtrate containing ferrous maleate is obtained;

[0011] (2) Add thiourea to the filtrate, raise the temperature to reflux, keep the temperature to react, and after the reaction is completed, cool, filter, wash with water, and dry to obtain ferrous fumarate.

[0012] The phase transfer catalyst is hexaoxacyclooctadecane (18-crown ether-6); the amount of the phase transfer catalyst is 3.5-5.0% of the mass of maleic anhydride; in terms of molar ratio, maleic anhydride: ferrous oxide: thiourea = 1: 1.02-1.05: 0.02-0.04.

[0013] In step (1), the temperature after heating is 45-50° C., 18%-20% dilute hydrochloric acid is used to adjust the pH to 5.5, and the stirring reaction time is 1-1.5 hours.

[0014] The ferrous maleate is transformed into ferrous fumarate by using thiourea for isomerization; the transformation isomerization is carried out by heating and reflux reaction, and the reaction time is 1h to 2.5h, preferably 1h to 1.5h.

[0015] After the ferrous fumarate transformation reaction is completed, the solution is cooled to 0-10° C., filtered, and vacuum dried to obtain the ferrous fumarate product.

[0016] The present invention adopts high-purity ferrous oxide to replace the traditional process ferrous sulfate, and the process does not produce additional waste salt (sulfate), solves the problem of waste salt, does not use reducing agents such as iron powder, sodium bisulfite, and thiourea dioxide, solves the problems of heavy metals, high iron impurity content, insufficient product purity, high COD wastewater, etc., and the reaction time is greatly shortened, the oxidation reaction of divalent iron is effectively curbed, the reaction temperature is reduced from 90°C to 105°C to 45-50°C, energy consumption is saved, and production cost is significantly reduced. The total process yield can reach more than 90%, and after testing, the ferrous fumarate content (on a dry basis) reaches more than 93.8% (national standard ≥93%), without sulfate impurities. DETAILED DESCRIPTION

[0017] The present invention is further described below in conjunction with embodiments. It should be noted that the following description is only for explaining the present invention and does not limit its contents.

[0018] Example 1

[0019] 197.1 g of maleic anhydride and 300 g of water were added to a 2000 ml four-necked flask. Under nitrogen protection, the mixture was stirred at room temperature for about 0.5 h. After the reaction solution was observed to be clear, 8.0 g of crown ether was added to the flask, and the mixture was heated to 45 ° C. During the stirring process, 148 g of ferrous oxide powder was added in batches. After the addition was completed, the pH was adjusted to 5.5 with 18% dilute hydrochloric acid, and the stirring reaction was maintained for 1 h. After the reaction was completed, the mixture was cooled to 25 ° C to 30 ° C, filtered, and the catalyst was reused. The filtrate was transferred to a four-necked flask, and 3.1 g of thiourea was continued to be added. The reaction solution was heated to reflux reaction, stirred for about 1 h, and cooled to 10 ° C. The obtained solid was filtered, washed with water, and dried in vacuo at 50 ° C to obtain 312.6 g of the product with a yield of 91.69% and a product purity of about 93.9%.

[0020] Example 2

[0021] A production process of ferrous fumarate, the specific steps of which are:

[0022] 197.1 g of maleic anhydride and 300 g of water were added to a 2000 ml four-necked flask. Under nitrogen protection, the mixture was stirred at room temperature for about 0.5 h. After the reaction solution was observed to be clear, 9.8 g of crown ether was added to the flask, and the mixture was heated to 50 ° C. During the stirring process, 148 g of ferrous oxide powder was added in batches. After the addition was completed, the pH was adjusted to 5.5 with 18% dilute hydrochloric acid, and the stirring reaction was maintained for 1.5 h. After the reaction was completed, the mixture was cooled to 25 ° C to 30 ° C, filtered, and the catalyst was reused. The filtrate was transferred to a four-necked flask, and 3.1 g of thiourea was continued to be added. The reaction solution was heated to reflux reaction, stirred for about 1.5 h, and cooled to 5 ° C. The obtained solid was filtered, washed with water, and dried in vacuo at 50 ° C to obtain 314.3 g of the product with a yield of 92.19% and a product purity of about 93.8%.

[0023] Example 3

[0024] 197.1 g of maleic anhydride and 300 g of water were added to a 2000 ml four-necked flask. Under nitrogen protection, the mixture was stirred at room temperature for about 0.5 h. After the reaction solution was observed to be clear, 9.8 g of crown ether was added to the flask, and the mixture was heated to 45 ° C. During the stirring process, 150 g of ferrous oxide powder was added in batches. After the addition was completed, the pH was adjusted to 5.5 with 25% dilute hydrochloric acid, and the stirring reaction was maintained for 1.5 h. After the reaction was completed, the mixture was cooled to 25 ° C to 30 ° C, filtered, and the catalyst was reused. The filtrate was transferred to a four-necked flask, and 3.1 g of thiourea was continued to be added. The reaction solution was heated to reflux reaction, stirred for about 2 h, and cooled to 10 ° C. The obtained solid was filtered, washed with water, and dried in vacuo at 50 ° C to obtain 315.3 g of the product, with a process yield of 92.48% and a product purity of about 94.1%.

[0025] Example 4

[0026] 197.1 g of maleic anhydride and 300 g of water were added to a 2000 ml four-necked flask. Under nitrogen protection, the mixture was stirred at room temperature for about 0.5 h. After the reaction solution was observed to be clear, 8.0 g of crown ether was added to the flask, and the mixture was heated to 45 ° C. During the stirring process, 150 g of ferrous oxide powder was added in batches. After the addition was completed, the pH was adjusted to 5.5 with 25% dilute hydrochloric acid, and the stirring reaction was maintained for 1 h. After the reaction was completed, the mixture was cooled to 25 ° C to 30 ° C, filtered, and the catalyst was reused. The filtrate was transferred to a four-necked flask, and 6.09 g of thiourea was continued to be added. The reaction solution was heated to reflux reaction, stirred for about 2.5 h, and cooled to 5 ° C. The obtained solid was filtered, washed with water, and dried in vacuo at 50 ° C to obtain 316.2 g of the product, with a process yield of 92.75% and a product purity of about 93.8%.

[0027] Comparative Example 1

[0028] Preparation of ferrous fumarate: add 29g of fumaric acid to a 500ml three-necked flask at room temperature, slowly add ammonia water while stirring, adjust the pH to -9, and the system is clear. At this time, add 69.5g of ferrous sulfate heptahydrate solid to the system, stir and heat to 100℃ and reflux for 5h. After the reaction is completed, cool and filter, wash the filter cake with 50ml of water and dry it at 60℃ for 5h. Obtain 39.74g of reddish brown solid powder ferrous fumarate, with a yield of 93.5%.

[0029] Comparative Example 2

[0030] Sodium fumarate is obtained by reacting sodium hydroxide with fumaric acid, and sodium fumarate is further reacted with ferrous sulfate to obtain ferrous fumarate. The specific operation is as follows: water is added into a salt dissolving kettle and the temperature is raised to 80-85° C., fumaric acid and sodium hydroxide are added in sequence, the temperature is raised to 100° C., and the ferrous sulfate is added into a reaction kettle together, and the temperature is raised to 100° C., a finished product is obtained after chemical reaction, discharge, cooling, centrifugal separation, drying, metering and packaging, and the ferrous fumarate content is about 91.5%.

[0031] Although the above describes the specific implementation methods of the present invention, it does not limit the scope of protection of the present invention. Based on the technical solution of the present invention, various modifications or variations that can be made by those skilled in the art without creative work are still within the scope of protection of the present invention.

Claims

1. A production process of ferrous fumarate, characterized in that, Under nitrogen protection, maleic anhydride and high-purity ferrous oxide are used as starting materials, and ferrous maleate is obtained by catalytic reaction with a phase transfer catalyst. The ferrous maleate is transformed and isomerized to obtain (E)-2-butenedioic acid ferrous salt, namely ferrous fumarate.

2. A production process for ferrous fumarate according to claim 1, characterized in that, The specific steps are: (1) under nitrogen protection, maleic anhydride is added to water, stirred to dissolve, and then a phase transfer catalyst is added, the temperature is raised, and high-purity ferrous oxide is added in batches. After the addition is completed, the pH is adjusted, the reaction is stirred, the temperature is lowered, and the filtrate containing ferrous maleate is obtained; (2) Add thiourea to the filtrate, raise the temperature to reflux, keep the temperature to react, and after the reaction is completed, cool, filter, wash with water, and dry to obtain ferrous fumarate.

3. A production process for ferrous fumarate according to claim 1, characterized in that, The phase transfer catalyst is hexaoxacyclooctadecane.

4. A production process for ferrous fumarate according to claim 2, characterized in that, The temperature after heating in step (1) is 45-50°C.

5. A production process for ferrous fumarate according to claim 2, characterized in that, The pH in step (1) is 5.

5.

6. A production process for ferrous fumarate according to claim 2, characterized in that, The amount of phase transfer catalyst used in step (1) is 3.5-5.0% of the mass of maleic anhydride.

7. A production process for ferrous fumarate according to claim 2, characterized in that, In terms of molar ratio, maleic anhydride: ferrous oxide: thiourea = 1: 1.02-1.05: 0.02-0.

04.

8. A production process for ferrous fumarate according to claim 1, characterized in that, The heat preservation reaction time in step (2) is 1h to 2.5h.

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