Method for isolating aqueous FECL3 hydrochloric acid solution from an aqueous multi-component system.

Abstract

The present invention relates to a method for isolating an aqueous FeCl3 solution of hydrochloric acid from an aqueous multicomponent system.

Description

[Technical Field]

[0001] The present invention provides a method for isolating an aqueous hydrochloric acid solution of FeCl3 from an aqueous multicomponent system, the following: a) Fe 3+ A step is provided in which an aqueous hydrochloric acid multi-component system containing ions is provided. b) A step in which the multi-component system from step a) is extracted with an organic solvent, c) The organic solvent from step b) is extracted with water, thereby obtaining an aqueous hydrochloric acid solution of FeCl3. The method includes the foregoing. [Background technology]

[0002] In many synthesis processes carried out on an industrial scale, FeCl3 is a valuable substance that can be used, for example, as an oxidizing agent. After use as an oxidizing agent, it often exists in the form of FeCl2 along with other components in multicomponent systems. FeCl2 can be oxidized back to FeCl3 by adding an oxidizing agent, such as Cl2, to the multicomponent system. In order to reuse this, an aqueous hydrochloric acid solution of FeCl3 must be isolated from the multicomponent system.

[0003] In the prior art, in the first step, Fe 3 An isolation method is described that provides an aqueous hydrochloric acid multicomponent system containing positive ions. In the second step, this multicomponent system is then extracted with an organic solvent to transfer as much of the dissolved FeCl3 as possible to the organic phase. In the third step, the organic solvent is extracted with water to obtain an aqueous hydrochloric acid solution of FeCl3.

[0004] The above-mentioned type of method is described, for example, in EP 0 675 077. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] EP 0 675 077 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, a drawback of known methods is that the yield of aqueous hydrochloric acid solution of FeCl3 for isolation from multicomponent systems is insufficient; that is, a considerable proportion of FeCl3 remains in the multicomponent system and therefore cannot be reused.

[0007] The object of the present invention is to provide a method for isolating an aqueous hydrochloric acid solution of FeCl3 from an aqueous multicomponent system, and in particular to provide a method for obtaining an aqueous hydrochloric acid solution of FeCl3 in high yield. [Means for solving the problem]

[0008] The object of the present invention is a method for isolating an aqueous hydrochloric acid solution of FeCl3 from an aqueous multicomponent system, the following: a) Fe 3+ A step is provided in which an aqueous hydrochloric acid multi-component system containing ions is provided. b) A step in which the multi-component system from step a) is extracted with an organic solvent, c) The organic solvent from step b) is extracted with water, thereby obtaining an aqueous hydrochloric acid solution of FeCl3. The multi-component system of step a) contains aqueous HCl vs. Fe 3+ This is achieved by the method described above, characterized in that the molar ratio of ions is ≥ 1.3:1. [Modes for carrying out the invention]

[0009] It has been shown that, surprisingly, the method according to the present invention can isolate a particularly high proportion of FeCl3 originally present in a multicomponent system in the form of an aqueous hydrochloric acid solution of FeCl3.

[0010] According to a preferred embodiment, aqueous HCl vs Fe 3The molar ratio of the + ions is in the range of 1.5:1 to 2.5:1, particularly preferably in the range of 1.8:1 to 2.3:1.

[0011] Aqueous HCl to Fe 3 It is even more preferable when the molar ratio of the + ions is in the range of 1.3:1 to 1.8:1, particularly preferably in the range of 1.3:1 to 1.7:1, and particularly preferably in the range of 1.3:1 to 1.5:1.

[0012] It is also preferable when the organic solvent contains or consists of molecules containing heteroatoms, preferably oxygen, sulfur or nitrogen atoms, particularly preferably oxygen atoms.

[0013] It is even more preferable when the organic solvent contains or consists of one or more of the following organic solvents: ethers, alcohols, ketones, and particularly preferably, one or more of the following organic solvents: 2-methoxy-2-methylpropane, diisopropyl ether, butanol, 2-methyl-1-propanol, 2-ethylhexane-1-ol, 4-methylpentan-2-one, 1-chloro-4-methylpentan-2-one, 3-chloro-4-methylpentan-2-one.

[0014] It is particularly preferable when the organic solvent contains or consists of 4-methylpentan-2-one.

[0015] According to a more preferred embodiment, the extraction in step b) is carried out countercurrently using an organic solvent.

[0016] When the extraction in step b) is a multi-stage extraction, it is preferably 3 to 7 stages.

[0017] It is also preferable to carry out the extraction in step c) countercurrently using water.

[0018] When the extraction in step c) is a multi-stage extraction, it is preferably 2 to 7 stages.

[0019] When the organic solvent contains or consists of 4-methylpentan-2-one, it is particularly preferred that the extraction in step b) is carried out countercurrently in 3 to 7 stages using the organic solvent, and the extraction in step c) is a multi-stage extraction in 2 to 6 stages countercurrently.

[0020] This method can preferably be carried out at a temperature within the range of 0 to 80°C, particularly preferably within the range of 10 to 50°C, and particularly preferably within the range of 20 to 40°C.

[0021] When the organic solvent contains or consists of 4-methylpentan-2-one, it is particularly preferred that the extraction in step b) is carried out countercurrently in 3 to 7 stages using the organic solvent, the extraction in step c) is a multi-stage extraction in 2 to 6 stages countercurrently, and the method is carried out at a temperature within the range of 20 to 40°C.

[0022] It is also preferred that this method is carried out continuously. It is particularly preferred when the organic solvent after extraction with water in step c) is reused in step b).

[0023] Fe in the aqueous multi-component system of step a) 3+ A method in which the concentration of ions is within the range of 0.01 to 2.3 mol / kg, particularly preferably within the range of 0.1 to 2 mol / kg, and particularly preferably within the range of 1.1 to 1.7 mol / kg is also preferred.

[0024] Also, when the organic solvent contains or consists of 4-methylpentan-2-one, the extraction in step b) is carried out countercurrently in 3 to 7 stages using the organic solvent, the extraction in step c) is a multi-stage extraction in 2 to 6 stages countercurrently, the method is carried out at a temperature within the range of 20 to 40°C, and Fe in the aqueous multi-component system solution of step a) 3+ It is particularly preferred when the concentration is within the range of 1.1 to 1.7 mol / kg.

[0025] A method in which the aqueous multi-component system in step a) contains dissolved alkali metal salts and / or alkaline earth metal salts and preferably NaCl and / or NaSCN is also advantageous. It is particularly advantageous when the aqueous multi-component system in step a) contains dissolved NaCl in the range of 0.01 to 3.5 mol / kg, preferably in the range of 0.1 to 1.5 mol / kg, particularly preferably in the range of 0.3 to 1 mol / kg. The method is also suitable for separating Fe 3+ ions from non-oxidized Fe 2+ ions, which is particularly suitable for separating from FeCl3.

[0026] The following examples illustrate the invention in more detail.

[0027] Experiments for the extraction of FeCl3 into the organic phase were carried out countercurrently in a seven-stage mixer-settler plant (in some experiments, no further changes occurred in the latter stages of extraction). An aqueous multi-component system containing 21 wt% FeCl3, 1 wt% FeCl2, 3 wt% sodium chloride and various amounts of HCl was extracted countercurrently with various solvents. In all tests, NaCl and FeCl2 remained in the aqueous phase. Approximately 1 equivalent of hydrochloric acid was introduced into the organic phase together with FeCl3.

[0028] Experiments for the back-extraction of the organic solvent from step b) with water were carried out countercurrently in a seven-stage mixer-settler plant (in all experiments, no further changes occurred in the latter stages of extraction).

Examples

[0029] Example 1: The aqueous multi-component system was extracted with 0.99 kg / kg of 4-methylpentan-2-one at 30 °C. The initial ratio of aqueous HCl to Fe 3+ ions in the water-soluble multi-component system was 2.6 mol / mol. The yield of FeCl3 in the organic phase after extraction was 100%.

[0030] Example 2: The aqueous multicomponent system was extracted with 0.85 kg / kg of 4-methylpentan-2-one at 30°C. The aqueous HCl vs. Fe ratio in the water-soluble multicomponent system was also examined. 3+ The initial ion ratio was 1.3 mol / mol. The yield of FeCl3 in the organic phase after extraction was 96.3%.

[0031] Example 3: The aqueous multicomponent system was extracted with 0.99 kg / kg of n-butanol at 40°C. The aqueous HCl vs. Fe ratio in the water-soluble multicomponent system was also examined. 3+ The initial ion ratio was 1.8 mol / mol. The yield of FeCl3 in the organic phase after extraction was 78.8% by mass.

[0032] Example 4: The aqueous multicomponent system was extracted with 0.60 kg / kg of 2-methoxy-2-methylpropane at 30°C. The aqueous HCl to Fe ratio in the aqueous multicomponent system was also determined. 3+ The initial ion ratio was 2.1 mol / mol, and 22% by weight of FeCl3 was present in the system. The yield of FeCl3 in the organic phase after extraction was 99.2% by weight.

[0033] Example 5: The aqueous multicomponent system was extracted with 0.61 kg / kg of 2-methoxy-2-methylpropane at 10°C. The aqueous HCl to Fe ratio in the aqueous multicomponent system was also extracted. 3+ The initial ion ratio was 1.5 mol / mol, and 24 wt% FeCl3 was present in the system. The yield of FeCl3 in the organic phase after extraction was 92.9 wt%.

[0034] Example 6: The aqueous multicomponent system was extracted with 0.57 kg / kg of diisopropyl ether at 30°C. The initial aqueous HCl to Fe ratio in the aqueous multicomponent system was... 3+ The ion ratio was 1.5 mol / mol, and 24% by weight of FeCl3 was present in the system. The yield of FeCl3 in the organic phase after extraction was 79.9% by weight.

[0035] Example 7: The organic solvent from step b) of Example 2, to which FeCl3 and HCl were added, was extracted with 0.54 kg / kg of water. FeCl3 and HCl were completely extracted into the water. The drained organic solvent 4-methylpentan-2-one contained no iron and only trace amounts of HCl.

[0036] Example 8: The organic solvent from step b) of Example 4, to which FeCl3 and HCl had been added, was extracted with 0.6 kg / kg of water. FeCl3 and HCl were completely extracted into the water. The drained 2-methoxy-2-methylpropane contained no iron and only trace amounts of HCl.

[0037] Comparative example: The aqueous multicomponent system was extracted with 0.99 kg / kg of 4-methylpentan-2-one at 40°C. The aqueous HCl to Fe ratio in the aqueous multicomponent system was... 3+ The initial ion ratio was 1.2 mol / mol, and 22% by weight of FeCl3 was present in the system. The yield of FeCl3 in the organic phase after extraction was 62.9% by weight.

Claims

1. FeCl ３ A method for isolating an aqueous hydrochloric acid solution of the following: a) Fe ３＋ A step is provided in which an aqueous hydrochloric acid multi-component system containing ions is provided. b) A step in which the multi-component system from step a) is extracted with an organic solvent. c) The organic solvent from step b) is extracted with water, where FeCl ３ Steps to obtain an aqueous hydrochloric acid solution Includes, In the multi-component system in step a), aqueous HCl vs. Fe ３＋ The method is characterized in that the molar ratio of the ions is in the range of 1.3:1 to 1.5:1, and the organic solvent contains 4-methylpentan-2-one.

2. The method according to claim 1, characterized in that the extraction in step b) is carried out in a countercurrent using an organic solvent.

3. The method according to claim 1 or 2, characterized in that the extraction in step b) is a multi-stage extraction.

4. The method according to claim 1 or 2, characterized in that the extraction in step c) is carried out in a countercurrent using water.

5. The method according to claim 1 or 2, characterized in that the extraction in step c) is a multi-stage extraction.

6. The method according to claim 1 or 2, characterized in that the method is carried out at a temperature in the range of 0 to 80°C.

7. The method according to claim 1 or 2, characterized in that the method is carried out continuously.

8. The method according to claim 7, characterized in that the organic solvent after extraction with water in step c) is reused in step b).

9. Fe in the aqueous multi-component system in step a) ３＋ The method according to claim 1 or 2, characterized in that the ion concentration is in the range of 0.01 to 2.3 mol / kg.

10. The method according to claim 1 or 2, characterized in that the aqueous multi-component system of step a) contains a dissolved alkali metal salt and / or alkaline earth metal salt.

11. The method according to claim 10, characterized in that the aqueous multi-component system of step a) contains dissolved NaCl in an amount in the range of 0.01 to 3.5 mol / kg.