RU2373217C1 - Method of producing iron (ii) fumarate - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: iron (II) fumarate can be used in different fields of chemical practice, in analytical control and in scientific research, through direct reaction of iron with fumaric acid in the presence of a catalyst, where the catalyst used is molecular iodine in amount of 0.025 to 0.1 mol/kg of the initial load, iron is taken in large excess in form of shells on the entire height of the reactor, false bottom and blade mixer, as well as in form of crushed cast iron and(or) reduced iron powder, the liquid phase solvent used is butylacetate, in which iodine and fumaric acid are at least partially dissolved, where fumaric acid is taken in amount of 0.8 to 1.2 mol/kg of the initial load, loading is done in the sequence: glass beads, liquid phase solvent, fumaric acid, iodine, and then crushed cast iron and(or) reduced iron powder; the process is started at room temperature and is carried out in a vertical type bead mill with ratio of mass of beads to mass of crushed cast iron and(or) reduced iron powder equal to 4:1, at temperature ranging from 18 to 45°C while bubbling air with flow rate of 0.95 l/min-kg of the liquid phase and using forced cooling and controlling using a sampling method until complete exhaustion of the loaded acid for formation of salt, after which stirring and cooling are stopped, the reaction mixture is separated from glass beads and unreacted crushed cast iron and(or) reduced iron powder and filtered, the residue is washed with butylacetate and taken for recrystallisation, and the filtrate and washing butylacetate are returned to the repeated process. Amount of acid used in extracting the product (without loss during purification) ranges from 89 to 96.5%, which depends on conditions for carrying out the process.

EFFECT: improved method of producing said product.

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Description

The invention relates to a technology for the production of iron (II) salt and fumaric acid and can be used in various fields of chemical practice, in analytical control and in scientific research.

A known method of producing fumarate of iron (II) (patent GB 1048867, publ. 11/23/1966), in accordance with which this salt is obtained by mixing a hot solution of fumaric acid (60-100 ° C) with metallic iron in the absence of air. The obtained ferrofumarate is separated by filtration, washed with hot water and dried under vacuum.

The disadvantages of this method are:

- the need to use a hot solution of fumaric acid, the receipt of which is an independent stage, requiring a certain time and supply of external heat;

- carrying out the process in the absence of air access;

- drying the obtained salt under vacuum.

A known method of producing anhydrous iron (II) fumarate (patent BE 658067, publ. 04/30/1965) by the interaction of metallic iron with an excess of fumaric acid at elevated temperature in an aqueous medium in the absence of air.

The disadvantages of this method are:

- described above for the GB patent, as well as

- the use of excess fumaric acid, which will have to be separated from the reaction mixture and used somewhere, and the resulting salt must be further purified from this reagent.

Closest to the claimed is a method of producing iron (II) fumarate (patent HU 40678, publ. 01/28/1987), in accordance with which the interaction of fumaric acid and metallic iron is carried out in an inert reaction medium in the presence of a catalyst, which may be (non) organic acid or iron salt at a temperature of 80-100 ° C.

The disadvantages of this method are:

1. Quite high temperatures of the process, which require the supply of external heat and which cannot be maintained without such a supply.

2. Acid catalysts are able to react with iron to form the corresponding salts, from which, as well as from residual acids, it is necessary to purify the target product.

3. The need to create an inert reaction medium and maintain it during the ongoing process.

The objective of the proposed solution is to conduct direct interaction of iron and (or) its alloy with fumaric acid under milder temperature conditions without supplying external heat to achieve and maintain the required temperature regime, without restricting the contact of the reaction mixture with air or even when sparging the latter with a small flow rate, without the use of an inert reaction medium and an excess of fumaric acid, as well as mineral and carboxylic acids as catalysts.

The problem is achieved in that molecular catalyst iodine is used in the amount of 0.025-0.1 mol / kg of the initial charge, iron is taken in large excess in the form of a shell along the entire height of the reactor, the false bottom and the paddle mixer, as well as in the form of crushed cast iron and (or) reduced iron powder, butyl acetate is used as a solvent of the liquid phase, in which iodine and fumaric acid are dosed, at least partially, dosed in an amount of 0.8-1.2 mol / kg of the initial load, the loading is carried out in the sequence of glasses nny beads, the solvent liquid phase, fumaric acid, iodine, and then granulated iron and (or) the reduced iron powder; the process starts at room temperature and is carried out in a vertical type bead mill with a mass ratio of beads and crushed cast iron and (or) reduced iron powder 4: 1 in the temperature range 18-45 ° С with air sparging at a flow rate of 0.95 l / min · kg the liquid phase and the use of forced cooling and control by sampling until the charged acid is almost completely consumed for salt formation, after which stirring and cooling are stopped, the reaction mixture is separated from glass beads and unreacted of the crushed cast iron and / or reduced iron powder and filtered, the precipitate is washed with butyl acetate and sent for recrystallization, and the filtrate and washing butyl acetate are returned to the repeated process.

Characteristics of the feedstock.

Reactive iron according to TU 6-09-2227-81

Steel 45 according to GOST 1050-74

Gray cast iron of the SCh brand in accordance with GOST 1412-70

Fumaric acid according to MRTU 6-09-4881-67

Crystalline iodine according to GOST 4159-79

Butyl acetate according to MRTU 6-09-5743-68.

The process of the claimed method is as follows. The calculated quantities of glass beads, butyl acetate, fumaric acid, iodine, and also crushed cast iron and (or) reduced iron powder are loaded into the steel casing of a bead mill with a shell along the entire height, a false bottom, and a high-speed paddle mixer made of steel 45. Mechanical stirring is turned on and air is bubbled in, the air flow is stabilized, forced cooling of the reactor is introduced using a liquid bath, and water is supplied to cool the condenser. The moment of inclusion of mechanical stirring is taken as the beginning of the experiment. During the process, samples of the reaction mixture are taken, in which the content of iron (II) and (III) salts and residual amounts of acid are determined. The process is accompanied by an increase in temperature in the reaction zone, which is restrained by forced cooling at a level of ≤45 ° С.

As soon as the analysis results indicate that the entire loaded acid is almost completely consumed, cooling, air bubbling and stirring are stopped, the reaction mixture (suspension) is separated from glass beads and unreacted fragmented metal and (or) its alloy, and then filtered. The precipitate is washed with a solvent of the liquid phase and sent to recrystallization. And the filtrate and wash solvent are returned to the reverse process.

Example 1

In a strictly defined place on the frame frame, a vertical type bead mill, the body and bottom of which is protected by a shell with an outer diameter of ~ 80 mm and a wall thickness of 3.5 mm and a false bottom with a thrust plate for a high-speed (1440 rpm) paddle mixer with a plate width 71 mm and a height of 42 mm and a flange connection with a lid that contains a return to the condenser, a stuffing box for the mixer, a socket for a submersible bubbler, a pocket for a thermocouple and a socket for installing a sampler, load 200 g of glass seed beads with a diameter of 1.8-2.7 mm, 173 g of butyl acetate, 23.21 g of fumaric acid, 3.81 g of iodine, and then 50 g of crushed gray cast iron with a maximum linear particle size of less than 5 mm. Mechanical stirring is turned on, air is bubbled at a flow rate of 0.95 l / min · kg of the liquid phase, and this moment is taken as the beginning of the process. It begins immediately and is accompanied by an increase in temperature in the reaction zone. It is held in place by a large volume water cooling bath. The initial temperature of the water in it determines the upper limit of the temperature range in the reaction zone. In this example, it was 25 ° C at an initial bath temperature of 18 ° C.

During the process, samples are taken of the reaction mixture, which are analyzed for the content of iron (II) and iron (III) salts, separately iron (II) iodide and molecular iodine, as well as the remaining unreacted acid.

After 120 minutes from the start of the experiment, the analysis showed an iron (II) salt content of 0.98 mol / kg, an iron (III) salt content of 0.015 mol / kg, a residual acid content of <0.01 mol / kg, which indicated that the process was almost complete. Stirring and bubbling of air are stopped, the reactor is disconnected from the lid and removed from the cooling bath, and its contents are poured into a container with a grate with dimensions of 0.3 × 0.4 mm located in the field of action of the permanent magnet. All beads and almost all unreacted cast iron trapped in the reaction mixture remain on this grate. Subsequently, they are removed from this lattice and returned to the repeated process.

The collected suspension of the reaction mixture is suction filtered. The resulting precipitate was washed with 50 g of butyl acetate to remove mainly iron (II) iodide and traces of molecular iodine, after which it was sent for further purification by recrystallization. And the filtrate, which is a solution of salts (including iodide) of iron (II) and iron (III), as well as a washing solvent, is returned to the repeated process.

The amount of product isolated in this example (excluding losses during recrystallization) is 0.193 mol. This corresponds to the expenditure of 96.5% of the loaded acid for its production.

Examples 2-8

The reactor, solvent, air consumption for bubbling, the mass of the initial reaction mixture and the crushed iron-containing material in it, the order of loading of the components, the sequence of operations during control, determining the moment of termination of the process, separating the product suspension from beads and unreacted alloy metal, isolating the product from the suspension and the separated components of the reaction mixture are similar to those described in example 1. They differ in the nature of the fragmented iron-containing material, iodine content and fumaric acid in the boot. The indicated differences and the results obtained are summarized in the table (MF - crushed gray cast iron; VZh - reduced iron powder).

The positive effect of the proposed solution is as follows.

1. As the iron-containing material used crushed gray cast iron, which may well be a waste of the manufacturing industry.

2. Iodine used as a catalyst to a lesser extent pollutes the product in comparison with mineral and carboxylic acids, as well as iron salts formed by them or introduced as a catalyst. This is predetermined by the fact that up to 80-90% of its maximum (theoretically possible) amount formed on the surface of iron or its alloy, formed as a result of the interaction of iodine with iron, is iron (II) iodide, i.e. where it is formed and where it is oxidized by atmospheric oxygen to a salt of fumaric acid and molecular iodine, which immediately turns into FeI ₂ . The iron (II) iodide and I ₂ (traces) entering the reaction mixture are in solution and are mainly returned to the repeated process with the filtrate and washing solvent.

3. The bulk of the catalyst is returned to the repeated process without any special methods and techniques of concentration, isolation and purification.

4. The proposed process is low temperature and can maintain a working temperature due to its own heat and heat generated during the operation of the bead mill.

5. The hardware design of the process is simple, and the equipment is not boiler surveillance.

6. The process is selective; the iron (III) salt formed as an impurity is returned to the repeated process with the filtrate and the washing solvent, where it has the ability to react with iron and turn into the target iron (II) salt.

7. The solvent used is available and in its bulk returns to the process, without requiring the use of special methods of cleaning, disposal, etc. Moreover, such a return may be multiple.

Claims (1)

A method of producing iron (II) fumarate by direct interaction of iron with fumaric acid in the presence of a catalyst, characterized in that molecular catalyst iodine is used in the amount of 0.025-0.1 mol / kg of the initial charge, iron is taken in large excess in the form of a shell throughout the height of the reactor, the false bottom and the paddle mixer, as well as in the form of crushed cast iron and (or) reduced iron powder, butyl acetate is used as a solvent for the liquid phase, in which iodine and fumaric are dissolved at least partially islotu dosed in an amount of 0.8-1.2 mol / kg of an initial load, loading is carried out in the sequence of glass beads, the solvent liquid phase, fumaric acid, iodine, and then granulated iron and (or) the reduced iron powder; the process starts at room temperature and is carried out in a vertical type bead mill with a mass ratio of beads and crushed cast iron and (or) reduced iron powder 4: 1 in the temperature range 18-45 ° С with air sparging at a flow rate of 0.95 l / min · kg the liquid phase and the use of forced cooling and control by sampling until the charged acid is almost completely consumed for salt formation, after which stirring and cooling are stopped, the reaction mixture is separated from glass beads and unreacted vshego granulated iron and (or) and reduced iron powder was filtered, washed with butyl acetate and passed to recrystallization, and the filtrate and washings butyl acetate is recycled to the second process.