RU2371430C1 - Method of producing manganese (ii) fumarate from manganese metal and manganese (iii) oxide - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of producing manganese (II) fumarate from manganese metal and its oxide (III) through direct reaction of the metal and its oxide Mn₂O₃ with an acid in the presence of a liquid phase and a stimulating iodine additive in a vertical type bead mill with glass beads as grinding agent. The metal and its oxide are loaded in molar ratio (2±0.1):1 in total amount of 7.87 to 10.93% of the mass of the load. Acid is added with 15 to 25% excess of the calculated value, equal to the number of moles of metal and twice the number of moles of metal oxide in the load. The base of the liquid phase is isoamyl alcohol, in which the iodine stimulating additive is dissolved in amount of 0.02 to 0.05 mol/kg. Glass beads are loaded first, in mass ratio to the reaction mixture of 1.35:1, and then later the liquid phase solvent, acid and stimulating additive, and after brief stirring, metal oxide and metal, stirring all the while. Taking this moment as the beginning of the process, forced cooling is introduced right away. Operating temperature is stabilised in the range 33 to 45°C and in this mode, the process is carried out until virtually quantitative conversion of metal and its oxide to the target salt, after which stirring and forced cooling are stopped. The reaction mixture is separated from the glass beads, cooled to temperature 5 to 6°C and kept at that temperature for 1 to 2 hours. The solid phase of the target salt is filtered off and washed with isoamyl on a filter cooled to approximately the same temperature, after which it is taken for purification by recrystallisation. The filtrate and the cleaning solvent, containing excess acid, the bulk of the stimulating additive and a certain amount of dissolved target salt, are returned for loading in the repeated process. The process is carried out in light temperature conditions. The target substance can be easily separated.

EFFECT: design of a low-waste method, which allows for obtaining target product from available manganese oxide with an easy to implement process.

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Description

The invention relates to a technology for producing manganese salts and can be used in various fields of chemical and other types of practice, in analytical control and in scientific research.

A known method of producing manganese acetate (US Pat. RF No. 2294921, publ. 10.03.2007, Bull. No. 7) by direct interaction of the metal and manganese dioxide with acetic acid in the presence of iodine additives as an oxidizing agent in a vertical type bead mill, according to which loading metal and its dioxide is produced in a molar ratio of 2: 1 in an amount of 11.8% by weight of the liquid phase, consisting of an organic solvent and acetic acid with a concentration of 3.4-5 mol / kg and dosed in a mass ratio with glass beads 1: 1 ,5; iodine is dissolved in the liquid phase in an amount of 0.025-0.070 mol / kg of the liquid phase, loading is carried out in the sequence: the liquid phase or its components separately, iodine, metal and its dioxide; the process begins at room temperature and lead to almost complete consumption of dioxide; the resulting salt suspension is separated from the main part of the unreacted metal and glass beads and sent for filtration, the filtrate is recycled, and the product precipitate is purified by recrystallization. In this case, ethyl cellosolve, ethylene glycol, 1,4-dioxane, iso-amyl and n-butyl alcohols are used as an organic solvent. And the content in the liquid phase of water up to 4 wt.% Practically does not affect the characteristics of the process.

The disadvantages of this method are:

1. As an oxidizing agent, manganese dioxide MnO _{2 is used} . It is far from obvious that it can be replaced by manganese (III) oxide Mn ₂ O ₃ and obtain an equivalent result or similar to that described.

2. Acetic acid is monobasic, rather low molecular weight, under normal conditions, liquid, able to mix with many solvents in a fairly wide range of ratios. Fumaric acid is dibasic, unsaturated, higher molecular weight, solid under normal conditions, the solubility of which in different solvents will be very different. There is no reason to expect that the conditions for the production of salts of acetate and manganese (II) fumarate will be identical throughout the complex or its defining part.

3. It is very simple to create a noticeable and even substantial excess of acetic acid in the initial charge, since this acid may well be not only a reagent, but also part of a combined solvent of the liquid phase. Fumaric acid in the latter quality is impossible, and creating a large excess in the load is much more difficult.

Closest to the claimed is a method of producing manganese (II) formate (US Pat. RF No. 2316536, publ. 02/10/2008, Bull. No. 4), in accordance with which the target salt is obtained by direct interaction of manganese oxide with a solution of formic acid in an organic solvent with an acid concentration of 3.5 ÷ 10.8 mol / kg, MnO ₂ , Mn ₂ O ₃ are used as manganese oxide,

Mn ₂ O ₄ , the process is carried out in the presence of manganese metal in a molar ratio with oxide (1.8 ÷ 2.2): 1 in the presence of a liquid phase dosed in a mass ratio with solid reagents (4.9 ÷ 11): 1 and glass beads 1: (1 ÷ 2), as well as a stimulating additive of iodine in an amount of 0.025 ÷ 0.100 mol / kg of the liquid phase; loading is carried out in sequence by the liquid phase as a whole or its components, then the stimulating additive of iodine is dissolved in it, then the metal and its oxide are loaded, then the bead mill is mechanically mixed and the process is conducted in the absence of external heat supply until the oxide is almost completely consumed, after whereupon the reaction mixture is separated from glass beads and heavy particles of unreacted metal and filtered, the resulting manganese formate precipitate is sent for recrystallization, and unreacted Lead manganese and filtrate are recycled. In this case, ethyl acetate, ethylene glycol, ethyl cellosolve, 1,4-dioxane, dimethylformamide and n-butyl alcohol are used as a solvent of the liquid phase.

The disadvantages of this method are:

1. Described above in paragraphs 2 and 3 in relation to the method of producing manganese acetate. Formic acid is lower molecular weight in relation to acetic acid. Therefore, it allows the creation of an even greater stoichiometric excess of this reagent in the load.

2. In the known solution, the metal is loaded with respect to the oxide with a substantial stoichiometric excess, which entails the separation of the unreacted part from the rest of the reaction mixture, as well as a return to the loading of the repeated process. It is desirable to exclude excess metal in the load and eliminate the associated separation and disposal operations.

3. The ability of the product to mainly accumulate in the solid phase, ceteris paribus, is predetermined by the solubility and some other physical properties of the target salt, and therefore the nature of the acid. There is no reason to believe that manganese formate and fumarate will have close physical characteristics, allowing the product to be separated from the rest of the reaction mixture in completely identical ways.

4. There is no reason to believe that the transition from the use of a low molecular weight monobasic acid to a higher molecular weight unsaturated dibasic acid will not entail noticeable changes in the sequence of individual operations and their operating characteristics.

The objective of the proposed solution is to select such load ratios of the metal and its oxide Mn ₂ O ₃ , as well as the conditions for their interaction with fumaric acid, which would ensure practically quantitative conversion of both metal and oxide to salt with a relatively small excess of carboxylic acid, as well as translation salts in the final reaction mixture mainly in the solid phase and separation of the latter by simple filtration.

The problem is achieved by the fact that the charge metal and its oxide are taken in a molar ratio (2 ± 0.1): 1 in a total amount of 7.87 ÷ 10.93% by weight of the charge, the acid is introduced with a 15-25% excess from the calculated value equal to the number of moles of metal and doubled the number of moles of metal oxide in the charge, iso-amyl alcohol is taken as the basis for the liquid phase, in which the stimulating additive of iodine in the amount of 0.02-0.05 mol / kg is dissolved, the loading starts from glass beads introduced in a mass ratio with the reaction mixture of 1.35: 1, then a solution is introduced The liquid phase isolator, acid and stimulating additive and, after briefly stirring without stopping, the metal oxide and metal, taking this moment as the beginning of the process, immediately introduce forced cooling, stabilize the operating temperature in the range 33-45 ° С and in this mode bring the process to practically quantitative conversion of the loaded metal and its oxide to the target salt, after which stirring and forced cooling are stopped, the reaction mixture is separated from glass beads, cooled to a temperature of 5-6 ° C and kept at this temperature for 1-2 hours, the solid phase of the target salt is filtered off and washed on the filter with iso-amyl alcohol cooled to about the same temperature, after which it is sent for purification by recrystallization, and the filtrate and washing solvent containing excess acid, the bulk a stimulant and a small amount of the dissolved target salt are returned to the loading process again.

Characteristics of the raw materials used

Reactive manganese according to GOST 6008-90.

Manganese oxide Mn ₂ O ₃ according to TU 6-09-3364-78.

Crystalline iodine according to GOST 4159-79.

Fumaric acid according to TU 6-09-4008-75.

iso-amyl alcohol according to GOST 5830-70.

The process of the claimed method is as follows. The vertical bead mill, equipped with a high-speed paddle-type mixer, a reversible refrigerator-condenser and a cooling bath with cold running water as a cooling agent, introduces the calculated amounts of glass beads, a solvent of a liquid phase, fumaric acid and a stimulating additive of iodine. The mechanical stirring is turned on and after 5-10 minutes, without stopping mixing, the calculated quantities of the metal and its oxide Mn ₂ O ₃ are introduced. This moment is taken as the beginning of the process. Immediately, the bead mill body is immersed in a cooling bath and the temperature changes in the reaction zone are observed. The process is exothermic, due to which, as well as the operation of the bead mill, its contents begin to heat up. By adjusting the degree of immersion of the casing of the bead mill in the bath, the temperature of the cooling water and the speed of its supply, they stabilize the temperature in the operating range and, in this mode, bring the process to practically quantitative conversion of the metal and its oxide into the target salt. This moment is determined by the method of sampling and determining in them the contents of the accumulated salt of manganese (II), as well as the spent oxide of manganese, manganese and acid.

At the end of the process, stirring and cooling are stopped, the reactor is removed from the frame frame nest, and its contents are poured into a container with a mesh with dimensions of 0.3 × 0.3 mm, where glass beads are separated from the suspension solution of the reaction mixture. To reduce the solubility of the target salt in the liquid phase of the reaction mixture, the latter is slowly cooled to 5-6 ° C and maintained at this temperature for 1.5-2 hours, and then filtered.

The separated beads are returned to the bead mill, which is placed in the corresponding nest of the frame frame and brought into working condition. Then, a certain amount of solvent of the liquid phase is introduced, mechanical stirring is switched on, during which the beads and the surfaces of the stirrer and body are washed from the reaction mixture remaining on them. Then the washing solvent is separated from the beads, cooled to 5-6 ° C and used to wash the precipitate of the target salt on the filter. The washed precipitate is squeezed out, somewhat dried in a stream of air, removed from the filter and sent for further purification by recrystallization. And the filtrate and washing solvent after analysis of the content of acid, iodine, manganese iodide and manganese fumarate and mass determination are returned to the loading process again.

Example 1

In a vertical type bead mill with a glass case in the form of a glass with an inner diameter of 53.7 mm and a height of 133 mm, equipped with a reflux condenser, a high-speed (2500 rpm) mechanical blade mixer with a rectangular pad of PCB with dimensions 51 × 56 mm and a thickness of 4.2 mm, load 135 g of glass beads with a diameter of 1.8-2.6 mm, 65.57 g of iso-amyl alcohol, 23.21 g of fumaric acid and 0.51 g of crystalline iodine. The reactor is placed in its place in the frame frame, closed with a lid with a stuffing box for the mixer, a loading hatch, a return to the condenser-reflux condenser and nests for measuring temperature and a sampler and include mechanical stirring. After 10 minutes of preparing a solution of acid and iodine in iso-amyl alcohol, 4.39 g of manganese and 6.32 g of its oxide Mn ₂ O ₃ are introduced through the loading door without stopping mechanical stirring. This moment is taken as the beginning of the redox process. Immediately from the bottom let down the cooling bath with running cooling water and observe the temperature change over time. Varying the immersion depth of the casing in the bath and the flow rate of cooling water, set the operating temperature at 42 ± 1 ° C, which is maintained until the completion of the process.

In the course of the process, samples of the reaction mixture are taken, in which the content of manganese fumarate, acid and metal oxide is determined. It turned out that 25, 50, 75 and more 98% of the calculated amount of the target salt of the degree of conversion were achieved in 4, 12, 28 and 56 minutes, respectively. After 60 minutes, stirring and cooling are stopped, the bead mill body is disconnected from the lid with a stirrer and lowered down, allowing the reaction mixture remaining on the stirrer to partially drain, which takes 5 minutes. After that, the contents of the reactor are poured into the receiving tank of the filter with a mesh with mesh sizes of 0.3 × 0.3 mm as a filter partition. The reaction mixture in the form of a salt suspension solution falls down, and glass beads remain on the grid. It is removed from the grid and returned to the reactor. The latter is placed at its workplace in a frame frame, connected to the lid with a stirrer and assembled in working condition. 43 g of iso-amyl alcohol are added, mechanical stirring is switched on, and the surface of the body, mixer, its shaft and beads are washed from the remnants of the reaction mixture for 5 minutes. After that, the washing solvent is separated from the beads as described above and sent for cooling to 5.3 ° C.

In parallel with the purification of the reactor, beads and stirrer from the remnants of the reaction mixture, the solution-suspension of the target salt collected after separation is cooled for 1 hour to a temperature of 5.6 ° C and kept at this temperature for 115 minutes. Next, the cooled reaction mixture is subjected to vacuum filtration. The filter cake is washed with spent chilled solvent, and then sent for purification by recrystallization. And the filtrate and wash solvent containing unreacted acid, an iodine-containing stimulant (partially in the form of MnI ₂ ) and small amounts of dissolved manganese fumarate are returned to the loading process again.

The yield of product separated by filtration is 94% of the calculated value with practically quantitative consumption of the metal and its oxide Mn ₂ O ₃ for the formation of the target salt.

Examples 2-9

The reactor, the starting reagents, the solvent of the liquid phase, the stimulating additive, the loading mass and its ratio with the mass of glass beads, the procedures for loading, carrying out the process, its termination and isolation of the product from the reaction mixture are similar to those described in Example 1. They differ in the molar ratio of metal and oxide in the load, the absolute metal content, an excess of fumaric acid, the total amount of solid reagents in the load, the initial dosage of iodine and the operating temperature of the process. These differences and the results are summarized in table. (PC - reaction mixture)

Characteristics of loading, process and product release Example 2 3 four 5 6 7 8 9 initial content of metal oxide, mol / kg 0.30 0.30 0.30 0.33 0.37 0.40 0.40 0.40 molar ratio of metal to oxide in the load 1.9: 1 2.0: 1 2.1: 1 2.0: 1 2.0: 1 1.9: 1 2.0: 1 2.1: 1 the content of fumaric acid, mol / kg 1.46 1.45 1,54 1,56 1.79 1.90 1.86 1.89 estimated excess of fumaric acid,% 25 21 25 eighteen 21 22 16 fifteen weight of loaded iso-amyl alcohol, g 73.91 74.10 73.02 72.26 68.70 66.52 67.07 66.62 the proportion of solid reagents (metal and its oxide) in the load,% by weight 7.87 8.03 8.20 8.84 9.91 10.49 10.71 10.93 the iodine content in the original PC, mol / kg 0,050 0,041 0,036 0,031 0,024 0,037 0,047 0,020 operating temperature of the process, ° C 33 37 40 38 36 45 45 43 time (min) to reach a certain share (in%) of the yield of the target salt from the calculated value 0.25 6 four 3 four 7 3 four 5 0.50 eleven 8 8 9 16 7 eleven fourteen 0.75 21 16 fifteen 22 29th 16 26 36 0.98 35 31 29th 36 41 40 55 67 total duration
process, min 40 35 36 42 47 48 61 74 washing solvent,% by weight of PC 37 39 41 43 40 46 45 47 the temperature of the reaction mixture at the time of filtration, ° C 5,0 5.7 6.0 6.0 5.8 5,4 5.2 5.1 temperature of the cooled washing solvent, ° C 5.3 5.2 5,0 5,4 5.7 5.8 6.0 6.0 exposure of chilled PC before filtering, min 120 115 111 92 87 60 73 82 the output separated by filtration of the target product,% of theory. 94 94 95 95 96 94 96 97

The positive effect of the proposed solution is:

1. Up to 50% of the target salt is obtained from manganese oxide Mn ₂ O ₃ , which, in comparison with metallic manganese, is more accessible as a natural compound (brownite, manganite).

2. The process is carried out under mild temperature conditions, largely supported by reaction heat and slight forced cooling.

3. The selected liquid phase allows using additional cooling of PC to ensure the transition of the bulk of the accumulated target salt into the solid phase, which is easily separated by simple filtering.

4. During the process, no interaction inhibitors accumulate, which allows the separated liquid phase to be repeatedly returned to the repeated process. With this return, unreacted carboxylic acid and a stimulating additive (in the form of I ₂ and manganese iodide) are utilized. All this allows us to characterize this process as low-waste.

5. During this process, there are no volatile waste-pollution.

6. The hardware design of the process is very simple. It does not have boiler surveillance equipment. Quite simple and methods of current control, as well as determining the moment of termination of the redox process.

Claims (1)

The method of producing manganese (II) fumarate from a metal and its oxide (III) by direct interaction of the metal and its oxide Mn ₂ O ₃ with an acid in the presence of a liquid phase and a stimulating additive of iodine in a vertical type bead mill with glass beads as a grinding agent, characterized the fact that the charge of the metal and its oxide is taken in a molar ratio (2 ± 0.1): 1 in a total amount of 7.87-10.93% by weight of the charge, the acid is introduced with a 15-25% excess of the calculated value, equal to the number of moles of metal and twice the number of moles of oxy and the metal in the load, isoamyl alcohol is taken as the base of the liquid phase, in which the stimulating additive of iodine is dissolved in an amount of 0.02-0.05 mol / kg, the download begins with glass beads introduced in a mass ratio with the reaction mixture of 1.35: 1, then a liquid phase solvent, an acid and a stimulating additive are introduced, and after short-term mixing without stopping it, the metal oxide and metal, taking this moment as the beginning of the process, are immediately forced to cool, the operating temperature is stabilized in the range 33-45 ° With and in this mode, the process is brought to a practically quantitative conversion of the loaded metal and its oxide into the target salt, after which stirring and forced cooling are stopped, the reaction mixture is separated from glass beads, the temperature is cooled to 5-6 ° C and kept at this temperature for 1- 2 hours, the solid phase of the target salt is filtered off and washed on the filter with isoamyl alcohol cooled to about the same temperature, after which it is sent for purification by recrystallization, and the filtrate and washing solvent, containing excess acid, the bulk of the stimulant and a small amount of the dissolved target salt are returned to the loading process again.