RU2291855C1 - Method of production of the ferric formiate (iii) - Google Patents

Abstract

FIELD: chemical industry; methods of production of the ferric formiate (III).

SUBSTANCE: the invention is pertaining to the field of chemical industry, in particular, to the method of production of the ferric formiate (III). The invention is dealt with the organic salts of the transition metals, in particular to production of the salt of the ferric iron and the formic acid. The method is realized by the direct interaction of the regenerated iron powder with the formic acid at presence of the molecular iodine and oxygen of the air as the oxidizing agents. The process is running in the medium of dimethylformamide as the dissolvent for preparation of the necessary liquid phase with the concentrations of the formic acid and iodine of 4.5-10 and 0.03-0.11 mole/kg accordingly. The mass ratio of the liquid phase and the powder of the regenerated iron is 3:1. The process starts at the room temperature and is conducted in the conditions of the forced cooling at the temperature of 50-80°C at the rate of the air consumption for the bubbling of 0.6-1.2 l\minute per 1 kg of the liquid phase. The process is terminated at accumulation of the ferric formiate (III) in the suspension up to 1-1.2 mole/kg. The suspension is separated from the particles of the non-reacted iron and then filtered. The filtrate is recycled to the repeated process, and the ferric formiate (III) (salt) is dried and either is used as required, or additionally is purified by the recrystallization. The technical result of the invention is simplification of the method with improvement of the economic indicators and the increased purity of the final product.

EFFECT: the invention ensures simplification of the method with improvement of the economic indicators and the increased purity of the final product.

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Description

The invention relates to a technology for the production of ferric salt and formic acid and can be used in various branches of the chemical and related industries, in laboratory practice, analytical control, as well as in scientific research in various fields.

A known method of producing iron (III) formate by reacting iron (III) nitrate with formic acid in an alcohol solution. The resulting red product is slightly soluble in alcohol and precipitates in the solid phase. It is better soluble in water and can attach up to two water molecules. In this case, the color becomes more yellow. In aqueous solutions, iron (III) formate is hydrolyzed to form the basic iron (III) formate and further up to iron (III) hydroxide (Kirk-Othmer Encyclopedia of Chemical Technology, 2000, vol. 14, p. 435).

The disadvantage of this method is that iron (III) nitrate is not a natural compound and requires its preliminary preparation. The same applies to formic acid.

Closest to the claimed is a method of producing basic iron (III) acetate (application No. 2004108558/04 (009022) from 09/20/05), in accordance with which the metal in the form of an iron shell and (or) a powder of reduced iron interacts with acetic acid in a reactor with intensive mechanical stirring at 17-25 ° C and intensive bubbling of air in the absence or in the presence of a stimulating additive of acetic anhydride until a certain amount of product is accumulated in the suspension, followed by separation of this suspension from the heavy parts c unreacted iron, filtering the basic iron acetate (III) and returning the filtrate to the load for a second process.

The disadvantages of this method are:

1. It cannot be fully implemented for the interaction of iron with formic acid for the reason that formic acid anhydride does not exist in nature.

2. Despite the fact that formic acid is stronger than acetic acid, there is no certainty that it will interact with the metal more easily and faster than acetic acid and specific methods of stimulating this interaction will not be required.

3. The liquid phase necessary for the process in the form of formic acid is much less convenient to use, primarily due to the higher volatility of such an acid.

4. There is no reason to believe that a suspension of basic iron (III) acetate in acetic acid and a suspension of iron (III) formate in formic acid will be similar to each other and will have approximately the same technological characteristics.

The objective of the proposed solution is to choose a solvent and ranges of concentrations of formic acid and iodine in it, in which the main product of the conversion would be iron (III) formate, and the process itself would proceed with a good yield in a technologically acceptable time.

The problem is achieved by the fact that dimethylformamide is taken as a solvent of the liquid phase, in which 0.03-0.11 mol / kg of iodine and 4.5-10 mol / kg of formic acid are dissolved, the liquid phase is introduced into intensive contact with powdered iron in a mass ratio of 3: 1, and the process starts at room temperature and is carried out with intensive mechanical stirring of iron powder and bubbling of air with a flow rate of 0.6-1.2 l / min per 1 kg of the liquid phase while containing a spontaneously rising temperature in the range of 50- 80 ° C due to the use of p forcibly cooling until 1-1.2 mol / kg of iron (III) formate is accumulated in the reaction mixture, after which the stirring is stopped, several minutes are left for sedimentation of heavy particles of unreacted iron, the red-brown suspension of the reaction mixture is carefully drained and sent to the filter, precipitate the filtered salt is dried, and the obtained filtrate is sent to a second process.

Characteristics of the raw materials used.

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

Crystalline iodine according to GOST 4159-79

Formic acid according to GOST 5848-73

N, N-dimethylformamide according to GOST 20289-74

The process of the claimed method is as follows. Into a reactor with intense mechanical stirring, including the bottom zone, a pre-prepared solution of iodine and formic acid in dimethylformamide or separately calculated amounts of solvent, formic acid and iodine, and then reduced iron powder are introduced. Mechanical stirring is turned on, air is bubbled in and this moment is taken as the beginning of the process. Observe the temperature change of the reaction mixture. As soon as it begins to grow, forced cooling of the reactor is introduced and the temperature is stabilized in the range of 50-80 ° C. The process is continued in this mode until the target product is accumulated in the reaction mixture in an amount of 1-1.2 mol / kg. Control is carried out by sampling during the process and determining the content of iron (III) and (II) salts in them.

Upon reaching the indicated moment, the stirring is stopped, forced cooling is removed and a few minutes are given for the settling of heavy iron particles. Then, the reaction mixture, which is a suspension of mainly iron (III) formate in the liquid phase of the system, is carefully drained through the side drain pipe of the reactor. The reaction mixture removed from the reactor is sent for filtration, the filtrate is recycled, and the precipitate is dried or, if necessary, recrystallized.

Example No. 1

In a protective steel jacket, a glass reactor with an internal diameter of 74.8 mm and a height of 137 mm, equipped with a reflux condenser, a high-speed paddle mixer (1440 rpm), not more than 0.3 mm from the bottom of the reactor, with an air bubbler , with a sampler and a loading hatch, 120 g of dimethylformamide, 55.5 g of formic acid and 4.5 g of crystalline iodine are successively introduced. The result is 180 g of the liquid phase with concentrations of formic acid and iodine, respectively 6.7 and 0.098 mol / kg Then 60 g of reduced iron powder are introduced, mechanical stirring and water supply to the reflux condenser are turned on. The temperature of the reaction mixture at this moment was 17 ° C. Bubbling air is supplied with a flow rate of 0.8 l / min per 1 kg of the liquid phase. This moment is taken as the beginning of the process.

After 23 minutes, the temperature increased to 32 ° C. Cooling is introduced using a liquid bath and the temperature is stabilized at 54 ° C. During the process, samples are taken of the reaction mixture, which are analyzed for the content of iron salts (II) and (III). The content of the latter throughout the process was dominant and reached 1.05 mol / kg 115 minutes after the start of the process. Stirring is stopped, the cooling bath is removed, and after 3 minutes of settling, the suspension of the iron (III) salt in the liquid phase of the final reaction mixture is drained through the drain pipe at a distance of 15.8 mm from the bottom of the reactor bottom. 184 g of suspension are obtained (the dead zones of the reactor are occupied by particles of unreacted iron and the reaction mass of the previous experiment, which excludes the loss of the reaction mixture for this reason). The latter is sent for filtration, the filtrate, which is a solution of formic acid, iodine, iron (II) iodide and iron (III) formate, is analyzed for the content of these components and sent to load the subsequent process. And the precipitate of iron (III) formate is dried. Received 34.3 g of product. If necessary, the resulting salt is further purified by recrystallization.

Example No. 2-8

The hardware design, the mass ratio of the liquid phase and iron, and the main sequence of operations are similar to those described in Example 1. They differ in that the liquid phase of the charge is prepared in advance, as well as the concentrations of formic acid and iodine in the liquid phase, the operating temperature, and the air flow rate for bubbling. The results are summarized in table.

Download and process specifications Example No. 2 3 four 5 6 7 8 The concentration in the liquid phase, mol / kg: formic acid 10 9.3 8.4 5.1 4,5 10 10 iodine 0,03 0.05 0,07 0.09 0.11 0.10 0,07 The temperature in the reaction zone, ° C: first 19 16 21 22 19 eighteen 17 at the time of forced cooling 33 31 28 thirty 31 25 27 working along the process fifty 56 64 69 68 80 73 Air consumption for bubbling, l / min per 1 kg of the liquid phase 0.8 1,2 1,0 0.9 0.9 0.6 0.6 The duration of the process, min 159 105 103 95 97 67 82 The content of iron (III) salt in the final reaction mixture, mol / kg 1.00 1.09 1.14 1.12 1,03 1.20 1.17 The suspension of the reaction mixture is unloaded, g 183 185 190 186 183 185 184 The output of iron (III) formate, g 31.6 35.9 38,2 37.1 31.9 38.3 37,4

The positive effect of the proposed solution is as follows.

1. The proposed method is simple and uses iron as a supplier of the salt cation, which is more available in comparison with iron (III) nitrate. And as an oxidizing agent, air is taken, which is a natural composition.

2. Simple and hardware design, in which there are no boiler supervision positions. And the poor solubility of the target product in the used liquid phase greatly facilitates its isolation.

3. When using reactive frequency reagents, the product is quite clean and in many cases does not require additional purification.

4. Iron (III) formate is stable to atmospheric action, and in organic media it is not susceptible to hydrolysis to the main iron (III) formate and beyond. Therefore, there is no need to use any protective measures in these areas.

Claims (1)

A method for producing iron (III) formate by reacting powdered reduced iron with acid in the presence of atmospheric oxygen as an oxidizing agent by effectively bubbling in a reactor with a high-speed paddle mixer, reflux condenser and bubbler, characterized in that dimethylformamide is used as a solvent for the liquid phase, in which 0.03-0.11 mol / kg iodine and 4.5-10 mol / kg formic acid are dissolved, the liquid phase is introduced into intensive contact with the reduced iron powder in a mass ratio solution 3: 1, and the process itself begins at room temperature and is carried out with intensive mechanical stirring of iron powder and bubbling of air with a flow rate of 0.6-1.2 l / min per 1 kg of the liquid phase while containing a spontaneously rising temperature in the range of 50-80 ° C due to the use of forced cooling until 1-1.2 mol / kg of iron (III) formate is accumulated in the reaction mixture, after which the stirring is stopped, several minutes are left for sedimentation of heavy particles of unreacted iron, a red-brown suspension of iron (III) formate ak gently drained and sent for filtration, the precipitate of the filtered salt is dried, and the resulting filtrate is returned to the second process.