RU2373186C2 - Method of producing basic phthalate of iron (iii) - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of producing basic phthalate of iron (III), which is used in chemical practice, analytical control and scientific research, through direct reaction of iron with atmospheric oxygen and phthalic acid in the presence of organic solvent, where the stimulating additive used is hydrochloric acid and inorganic chlorides in amount ranging from 0.013 to 0.062 mol/kg of the load. The liquid phase solvent is n-butyl alcohol iron which is crushed and moved in the reaction zone in form of steel balls with diametre ranging from 2.2 to 3.7 mm, alone or in combination with crushed cast iron in any mass ratio. Initial content of phthalic acid is varied from 1.0 to 1.5 mol/kg of the load. The reactor used is a vertical type bead mill with the grinding agent in form of steel balls and crushed alloy of iron together with glass beads in mass ratio of iron-containing reagent, beads and the rest of the load equal to 1:1:0.6 with a spill pipe as a bubbler during the process. Loading is done in the following sequence: grinding agent and moved metal, liquid phase solvent, phthalic acid, chlorine-containing stimulating agent, and the process itself starts with heating contents of the reactor to 35°, is carried out with self-heating in the range 35 to 50°C while stirring continuously, bubbling air at a rate of 2.3 to 3.1 l/(min kg of load), while maintaining temperature using a cooling liquid bath and controlling the process using a sampling method until exhaustion of all loaded acid, after which bubbling is stopped. Suspension of the reaction mixture is let to flow under gravity through a net lying in the field of a permanent magnet into the receiving tank of a vacuum filter, after which it is filtered. The residue is washed with the liquid phase solvent and taken for purification, and the primary filtrate and washing solvent are returned to the repeated process.

EFFECT: non-waste method at low temperature; wastes from other industries can be used as reagents; desired products can be separated by simple filtration.

2 cl, 8 ex

Description

The invention relates to a technology for the production of basic iron (III) phthalate and can be implemented in laboratory and industrial chemical and other fields of practice, in analytical control and in scientific research.

Known electrosynthesis of metal carboxylates, including iron (III) phthalate (US Patent 5443698), in accordance with which the process is carried out in a galvanic bath with mechanical stirring to maintain the emulsion and increase the speed of the process with an anode of iron, cobalt, copper and other supplies a metal salt cation and a cathode of an electrolytically inert material (platinum, graphite, etc.). Hexane, petroleum ether, etc. are used as the organic phase to create the emulsion. Sodium hydroxide, sodium chloride, sodium acetate, etc. are used as an electrolyte that provides sufficient current in the emulsion. Both direct and alternating current are possible.

Metal carboxylate is isolated from the emulsion by simply separating the organic phase and isolating it from the latter salt by known techniques.

The disadvantages of this method are as follows.

1. A fairly large range of chemicals involved in it.

2. Electrosynthesis as such cannot be attributed to simple methods; quite complex and specific equipment used for its implementation.

Closest to the claimed is a method of obtaining a complex of iron (III) with three anions of salicylic acid (RF patent No. 2304575 according to application No. 2006102401/04), in accordance with which the product is obtained by direct interaction of a metal or its alloy with an acid in the presence of air and dimethylformamide as a solvent of the liquid phase, is separated by filtration and purified by recrystallization. At the same time, the initial content of salicylic acid in dimethylformamide is 3.4–4.0 mol / kg, air consumption for bubbling is 3.9–5.4 l / min · kg of charge; reduced iron powder is used as a source of iron transported by a mechanical stirrer, crushed gray cast iron or broken steel chips, and the process is stopped when the product accumulates in an amount of 1.12-1.30 mol / kg.

The disadvantages of this method are as follows.

1. Despite the fact that salicylic and phthalic acids are orthosubstituted, the substituents are fundamentally different. In the first case, it is hydroxyl, and in the second, a carboxyl group. Salicylic acid is monobasic, and phthalic dibasic. In this regard, there is no reason to expect that the processes for obtaining iron (III) compounds with the indicated acids will proceed in the same way and with similar characteristics.

2. Salicylic acid forms a complex of iron (III) with three acid anions. Phthalic acid can also form a complex, but of a completely different structure. The formation of salt, both primary (more likely) and secondary, is not excluded. The complex may also include a solvent, which dimethylformamide does not have to be.

3. The solubilities of salicylic and phthalic acids in different environments are different. The same can be said about compounds of iron (III) with these acids. Therefore, the dynamics of changes in the phase state of the reaction mixtures will be different. In addition, for dibasic phthalic acid, there is no point in focusing on such high contents of this reagent in the initial charge.

4. There is no reason when working with phthalic acid to focus on the characteristics of the termination of the redox process described in the known solution (that is, upon reaching the product content of 1.12-1.30 mol / kg).

5. In a known solution, the process is carried out in a reactor with mechanical stirring with a paddle mechanical stirrer in the absence of a halogen-containing stimulating additive. It is not at all obvious that this situation should be maintained during the transition from salicylic acid to phthalic acid.

The objective of this solution is to identify the necessary conditions and select an acceptable solvent and stimulating additive for the selective conversion of phthalic acid to basic iron (III) phthalate in a redox-related redox process and its hardware design.

The problem is achieved in that hydrochloric acid or inorganic chlorides in an amount of 0.013-0.062 mol / kg of load are used as a stimulating additive, n-butyl alcohol is taken as a solvent of the liquid phase, steel balls with a diameter of 2 are used as crushed and transferred to the reaction zone, 2 3.7 mm alone or together with crushed cast iron in any mass ratio between each other, the initial content of phthalic acid varies in the range of 1.0-1.5 mol / kg of load, bi ernuyu vertical mill type grind agent in the form of steel balls and crushed iron alloy together with glass beads in a weight ratio of iron-containing reagent, beads and the remaining load of 1: 1: 0.6 with a drain pipe of the sparger as during the process; loading is carried out in the sequence: a grinding agent and a moving metal, a solvent of the liquid phase, phthalic acid, a chlorine-containing stimulating additive, and the process itself begins by heating the contents of the reactor to 35 ° C and is carried out by self-heating in the temperature range of 35-50 ° C under continuous stirring and bubbling of air with a flow rate of 2.3-3.1 l / min · kg load, containing the temperature of the cooling liquid bath and monitoring the progress of the process by sampling until the complete consumption of the entire loaded acid, after which the air bubbling is stopped, the suspension of the reaction mixture is allowed to merge by gravity through the mesh located in the field of action of the permanent magnet into the receiving tank of the vacuum filter, after which it is filtered, the precipitate is washed with a liquid solvent and sent for purification, and the primary filtrate and washing solvent are returned into the repeat process.

At the same time, concentrated hydrochloric acid or ammonium chloride, sodium, barium, or iron are taken as a chlorine-containing stimulating additive.

Characteristics of the raw materials used

Steel 45 according to GOST 1050-74

Gray cast iron grade SCh 15-32 but GOST 1412-70

Phthalic acid according to GOST 4556-68

n-Butyl alcohol according to GOST 6006-51

Hydrochloric acid according to GOST 3118-67

Ammonium chloride but GOST 3773-60

Sodium chloride according to TU 113-13-14-82

Barium chloride according to GOST 4108-65

Iron (III) chloride according to GOST 4147-74

The process of the claimed method is as follows. Glass beads and steel balls up to 4 mm in diameter or a mixture of steel balls and crushed cast iron in any mass ratios between themselves and in the mass ratio with glass beads and the rest are loaded into a bead mill with a paddle mixer and a drain pipe used as a bubbler during the process. loading 1: 1: 0.6. The rest, i.e. not containing metal, in the future simple loading includes a solvent of the liquid phase, phthalic acid and a chlorine-containing stimulating additive, which are loaded in the indicated sequence without any interruptions between operations. After loading is complete, the bead mill body is placed in a liquid heating bath preheated to 35 ° C, and the gas line and the necessary measuring devices are connected. Then air is supplied for bubbling, its flow rate is stabilized, mechanical stirring is turned on, and this moment is taken as the beginning of the process. The process is exothermic and begins to develop even at room temperature. Due to the reaction heat, the temperature in the reaction zone begins to rise and reaches the temperature in the bath in a matter of minutes. From this moment, the bathhouse automatically becomes cooling from the heating one, and the coolant inside it begins to heat up. With a rather large mass of coolant in the bath, it can significantly inhibit the temperature increase of the reaction mixture and carry out the process in a rather limited temperature range.

The process is monitored by sampling the reaction mixture and determining the content of iron (III) and iron (II) salts in them. The process is stopped when almost all of the loaded acid is consumed for the formation of these salts. At this moment, the air supply to the bubbling is stopped, mechanical stirring, the gas line is closed, the drain pipe with a grid at its inlet is opened, a magnet is brought to it and the suspension of the reaction mixture is allowed to merge by gravity through the grid located in the field of action of the permanent magnet into the vacuum receiving tank filter, after which it is filtered, the resulting precipitate is washed with a solvent of the liquid phase, filtered again and sent for purification. The primary filtrate and wash solvent are recycled.

Example No. 1

In a bead mill with a stainless steel case with an inner diameter of 110 mm, a height of 190 mm and a wall thickness of 13 mm, having a lower drain pipe under the thrust bearing for the end of the shaft of the paddle mixer with 4 mesh channels closed for draining 0.4 mm in diameter at a 90 ° angle to each other in the region of the lower point of the bottom of the body and equipped with a massive cover with a stuffing box for a high-speed (1260 rpm) mixer, a pocket for measuring temperature, lowered into the volume in close proximity to the side wall and ending just above the top to the omks of the agitator blades, a pocket for a sampler, a loading hatch with a screw cap, and also access to a reflux condenser, load 800 g of glass beads and 800 g of steel balls with a diameter in the range from 2.2 to 3.7 mm, 382.7 g n-butyl alcohol as a solvent of the liquid phase, 95.7 g of phthalic acid and 1.6 g of 33% hydrochloric acid. A liquid bath preheated to 35 ° C is brought in from below and an air flow with a flow rate of 2.7 l / (min · kg load) is supplied to the bubbler through a drain pipe as a bubbler. This point in time is taken as the beginning of the process. At first the bathhouse was warm. But the ongoing process is exothermic. After 9 minutes, due to the reaction heat, the temperature of the reaction mixture exceeded the temperature of the coolant in the bath, which automatically turned into a cooling one. As such, it remains until the termination of the process at a temperature of 42 ° C. This happened after 193 minutes from the start.

During the process, samples were taken of the reaction mixture, which were monitored for the content of iron (III) salts, which are the dominant product under the selected conditions, and iron (II). The process was stopped when almost all the loaded phthalic acid was spent on the formation of these salts.

At a designated point in time, air bubbling was stopped, the liquid bath was lowered below the level of the end containing the mesh (for separating relatively large solid particles), the drain pipe, a magnet was brought to it, the drain pipe was opened and the reaction mixture was removed by gravity to the vacuum receiving tank filter, while separating it from glass beads and steel balls, which gradually decreased in size, but did not crush. At the same time, the suspension of the reaction mixture was cooled to ambient temperature. The reaction mixture collected in the indicated container was filtered. The filtrate was returned to the reverse process, and the filter cake was sent to a tank specially designed for washing. Here he was stirred up in 100 g of n-butyl alcohol, the resulting suspension was thoroughly mixed and, after 15 minutes, sent for filtration. The precipitate was carefully squeezed out on a filter and sent for drying in an oven, where the basic salt lost the molecule of n-butyl alcohol associated with it, after which it corresponded to the basic formula of iron (III) phthalate. When drying at room temperature, the indicated loss of the solvent molecule did not occur, although the powder state of the product was quite easily achieved. The washing solvent was returned to the repeated process.

The yield of the isolated iron (III) salt was 0.55 mol. Part of the iron (III) salt and traces of the iron (II) salt are returned to the reverse process with the filtrate and the washing solvent.

Examples 2-8

The reaction apparatus, the solvent of the liquid phase, the mass of the rest of the charge, the ratio of glass beads: iron moved by the stirrer: the rest of the load, the sequence of operations when loading, carrying out the process, processing the reaction mixture and isolating the target product, as well as the characteristics of the moment of termination of the salt production process are similar to those described in the example 1. Differ in the initial content of phthalic acid, the operating temperature range, air flow rate for bubbling, the nature and amount of chlorine used General stimulating additives, as well as the ratio of the masses of steel balls and crushed cast iron. The obtained process characteristics and other results are summarized in the table.

The positive effect of the proposed solution is as follows.

1. The method is simple to implement, it is carried out at rather low temperatures, the temperature regime is mainly maintained due to its own heat, it does not have any obvious waste that could not be used in the process itself.

2. In addition to phthalic acid, natural air and waste from other industries (crushed cast iron, etc.) are used as other reagents.

3. The process is highly selective and is not accompanied by the accumulation of substances that would significantly interfere with its course.

4. The bulk of the target product accumulates in the solid phase and can be separated from the rest of the reaction mixture by simple filtration.

5. The equipment for the process is simple and easily accessible.

6. As stimulants, readily available substances (including those of natural origin, for example, NaCl) are used.

Claims (2)

1. The method of producing basic iron (III) phthalate by direct interaction of iron with atmospheric oxygen and phthalic acid in the presence of an organic solvent, characterized in that hydrochloric acid and inorganic chlorides are used as a stimulating additive in an amount of 0.013-0.062 mol / kg load, with a solvent of the liquid phase take n-butyl alcohol, steel balls with a diameter of 2.2-3.7 mm, crushed and moved in the reaction zone of iron, independently or together with crushed cast iron in any mass in the ratio to each other, the initial content of phthalic acid varies in the range of 1.0-1.5 mol / kg load, a vertical type bead mill with a grinding agent in the form of steel balls and crushed iron alloy together with glass beads in a mass ratio is used as a reactor iron-containing reagent, beads and the rest of the load 1: 1: 0.6 with a drain pipe as a bubbler during the process, the loading is carried out in the sequence: grinding agent and transferred metal, solvent liquid PS, phthalic acid, a chlorine-containing stimulating additive, and the process itself begins with heating the contents of the reactor to 35 ° C and is carried out with self-heating in the range of 35-50 ° C under continuous stirring, air sparging with a flow rate of 2.3-3.1 l / (min · kg load), restraining the temperature with a cooling liquid bath and monitoring the progress of the process by sampling until almost all of the loaded acid has been consumed, after which air bubbling is stopped, and the suspension of the reaction mixture can be drained by gravity through the mesh that extends in the field of action of the permanent magnet into the receiving container of the vacuum filter, after which it is filtered, the precipitate is washed with a solvent of the liquid phase and sent for purification, and the primary filtrate and the washing solvent are returned to the repeated process. 2. The method according to claim 1, characterized in that as a chlorine-containing stimulant take concentrated hydrochloric acid, ammonium chloride, sodium, barium or iron.