A method for preparing potassium diformate

Abstract

The present application relates to the technical field of preparation of potassium dimethylate, and particularly relates to a method for preparing potassium dimethylate. The present application provides a method for preparing potassium dimethylate, comprising the following steps: mixing an aqueous solution of glyoxal and an aqueous solution of potassium permanganate to perform a redox reaction; sequentially performing concentration, crystallization and filtration on a product system obtained by the redox reaction; filtering a solid phase to obtain manganese (II) formate dihydrate; mixing a filtrate obtained by the filtering and a formic acid solution to perform a synthesis reaction, thereby obtaining potassium dimethylate; and the temperature of the crystallization is 1-5 DEG C. The present application uses cheap glyoxal and potassium permanganate as raw materials to prepare potassium dimethylate, and the data of examples show that the yield of potassium dimethylate prepared by the present application is 98.90%.

Description

Technical Field

[0001] This invention relates to the field of potassium diformate preparation technology, and specifically to a method for preparing potassium diformate. Background Technology

[0002] Potassium diformate is an organic acid salt, a white crystalline or crystalline powder composed of one molecule of formic acid and one molecule of potassium formate linked by hydrogen bonds. It is readily soluble in water, with the molecular formula HCOOH·HCOOK and a molecular weight of 130.14. It has been reported to possess antibacterial properties, improve feed digestibility, and promote growth.

[0003] The reported methods for preparing potassium diformate include: formic acid-potassium formate method (CN202010545669.4, CN201610771411.X), formic acid-potassium oxide method (CN200610043769.7), formic acid-potassium hydroxide method (CN201910881915.0) and formic acid-potassium carbonate method (CN200810195465.1). However, all of the above methods for preparing potassium diformate have the drawbacks of high raw material costs and low yield. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention provides a method for preparing potassium diformate, which reduces the preparation cost of potassium diformate while ensuring the yield of potassium diformate.

[0005] This invention provides a method for preparing potassium diformate, comprising the following steps:

[0006] An aqueous solution of glyoxal and an aqueous solution of potassium permanganate are mixed to carry out a redox reaction;

[0007] The product system obtained from the redox reaction was sequentially concentrated, crystallized, and filtered.

[0008] The solid phase obtained after filtration was manganese formate dihydrate (II);

[0009] The filtrate obtained from filtration is mixed with formic acid solution to carry out a synthesis reaction, yielding potassium diformate;

[0010] The crystallization temperature is 1–5°C.

[0011] Preferably, the volume concentration of the aqueous solution of glyoxal is 8-12%.

[0012] Preferably, the concentration of the aqueous solution of potassium permanganate is 0.15–0.2 mol / L.

[0013] Preferably, the volume ratio of the aqueous solution of glyoxal to the aqueous solution of potassium permanganate is 1:2.

[0014] Preferably, the mixing involves adding an aqueous solution of potassium permanganate dropwise to an aqueous solution of glyoxal.

[0015] Preferably, the dropping rate is 0.7 to 1.0 mL / min.

[0016] Preferably, the redox reaction is carried out under stirring conditions, and the stirring speed is 10 to 30 rpm.

[0017] Preferably, the temperature of the redox reaction is 20–40°C, and the holding time is 15–45 min.

[0018] Preferably, the volume of the concentrated system is 1 / 5 to 6 of the volume of the unconcentrated system.

[0019] Preferably, the crystallization is a cooling crystallization, and the cooling crystallization temperature is 1-5°C.

[0020] Preferably, the formic acid solution has a mass concentration of 80-90%.

[0021] This invention provides a method for preparing potassium diformate, comprising the following steps: mixing an aqueous solution of glyoxal and an aqueous solution of potassium permanganate, and carrying out a redox reaction; concentrating, crystallizing, and filtering the product system obtained from the redox reaction sequentially; the solid phase obtained after filtration is manganese formate(II) dihydrate; mixing the filtrate obtained from filtration with a formic acid solution, and carrying out a synthesis reaction to obtain potassium diformate; the crystallization temperature is 1-5°C. This invention uses inexpensive glyoxal and potassium permanganate as raw materials, and obtains a mixture of potassium diformate and potassium formate through a redox reaction. The reaction conditions are mild, requiring no high temperature, thereby improving the yield of potassium diformate. Furthermore, potassium formate in the mixture is further converted to potassium diformate by adding formic acid. Therefore, the preparation method provided by this invention can improve the yield of manganese formate dihydrate and potassium diformate. Attached Figure Description

[0022] Figure 1 Thermogravimetric analysis (temperature-weight loss) graph of manganese(II) formate dihydrate prepared in Example 12;

[0023] Figure 2 Thermogravimetric analysis (temperature-heat flow) graph of manganese(II) formate dihydrate prepared in Example 12;

[0024] Figure 3 This is a microscopic image of manganese formate dihydrate prepared in Example 12;

[0025] Figure 4 The infrared spectrum of manganese(II) formate dihydrate prepared in Example 12;

[0026] Figure 5The image shows the infrared spectrum of potassium diformate prepared in Example 12. Detailed Implementation

[0027] This invention provides a method for preparing potassium diformate, comprising the following steps:

[0028] An aqueous solution of glyoxal and an aqueous solution of potassium permanganate are mixed to carry out a redox reaction;

[0029] The product system obtained from the redox reaction was sequentially concentrated, crystallized, and filtered.

[0030] The solid phase obtained after filtration was manganese formate dihydrate (II);

[0031] The filtrate obtained from filtration is mixed with formic acid solution to carry out a synthesis reaction, yielding potassium diformate;

[0032] The crystallization temperature is 1–5°C.

[0033] This invention involves mixing an aqueous solution of glyoxal and an aqueous solution of potassium permanganate to carry out a redox reaction, thereby obtaining manganese formate dihydrate.

[0034] In this invention, the volume concentration of the glyoxal aqueous solution is preferably 8-12%, more preferably 10%. In this invention, the concentration of the potassium permanganate aqueous solution is preferably 0.15-0.2 mol / L, more preferably 0.16-0.18 mol / L. In this invention, the volume ratio of the glyoxal aqueous solution to the potassium permanganate aqueous solution is preferably 1:2.

[0035] In this invention, the mixing is preferably achieved by adding an aqueous solution of potassium permanganate dropwise to an aqueous solution of glyoxal. The dropping rate is preferably 0.7–1.0 mL / min, more preferably 0.7 mL / min.

[0036] In this invention, the temperature of the redox reaction is preferably 20-40°C, more preferably 30°C, and the holding time is preferably 15-45 min, more preferably 30 min.

[0037] In this invention, after the redox reaction, the system obtained from the redox reaction is further subjected to concentration, crystallization and filtration in sequence, and the solid phase obtained by filtration is manganese formate dihydrate.

[0038] In this invention, the equation for the redox reaction is:

[0039] 2KMnO4+4CHOCHO+4H2O→2{(HCOO)2Mn·2H2O}+HCOOH·HCOOK+HCOOK+CO2↑

[0040] In this invention, the volume after concentration is preferably 1 / 5 to 6 of the volume of the system before concentration. In this invention, the concentration is not specifically limited, and concentration operations well known in the art can be used.

[0041] In this invention, the crystallization temperature is preferably 1–5°C, more preferably 4°C. In this invention, the filtration process is not specifically limited; any filtration method well-known in the art can be used.

[0042] In this invention, the filtrate obtained by filtration is mixed with formic acid solution and a synthesis reaction is carried out to obtain potassium diformate.

[0043] In this invention, the mass concentration of the formic acid solution is preferably 80-90%, more preferably 85%.

[0044] In this invention, the temperature of the synthesis reaction is preferably 40–60°C, more preferably 50°C, and the time is preferably 0.8–1.2 h, more preferably 1 h. In this invention, the synthesis reaction is preferably carried out under stirring conditions, and the stirring speed is preferably 10–30 rpm, more preferably 15 rpm.

[0045] In this invention, after the synthesis reaction, it is preferable to further cool and crystallize the system obtained from the synthesis reaction in sequence to obtain potassium diformate.

[0046] In this invention, the cooling is preferably performed to room temperature. In this invention, the crystallization is preferably performed by cooling, and the cooling temperature for crystallization is preferably 4°C.

[0047] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0048] Examples 1-20

[0049] 20 mL of potassium permanganate aqueous solution was added dropwise to 10 mL of glyoxal aqueous solution with a volume concentration of 10% at a rate of 0.7 mL / min to carry out a redox reaction. After the redox reaction was completed, the system obtained by the redox reaction was concentrated sequentially. The volume of the concentrated system was 1 / 6 of that before concentration. The concentrated system was placed in a refrigerator at 4°C for crystallization and then filtered. The solid phase obtained by filtration was manganese formate dihydrate.

[0050] The filtrate obtained by filtration was mixed with an 85% formic acid solution and stirred at 50°C for 1 hour (synthesis reaction). After the reaction was completed, the synthesis reaction system was cooled (cooling temperature was 4°C) and crystallized to obtain potassium diformate. The solid phase obtained by filtration was manganese formate dihydrate. The reaction conditions and yield of manganese formate dihydrate (II) in Examples 1 to 20 are shown in Table 1.

[0051] Table 1. Statistical table of redox reaction conditions and product yields in Examples 1-20

[0052]

[0053]

[0054] Thermogravimetric analysis was performed on the manganese(II) formate dihydrate prepared in Example 12. The test results are shown in [Figure 1]. Figures 1-2 ,from Figures 1-2 It can be seen that the first weight loss state of manganese formate dihydrate (II) is between 40.47 and 178.63℃, mainly due to the volatilization of water molecules, with a weight loss of 20.75% and a residual weight of 79.25%. This allows us to determine the amount of water of crystallization contained in the substance. Further calculations show that it contains two molecules of water of crystallization. The second weight loss state of manganese formate dihydrate (II) is between 190.38 and 377.42℃, mainly due to the decomposition of manganese formate with increasing temperature, with a weight loss of 39.58% and a residual weight of 39.67%. The graph shows that the absorption peak of the water of crystallization in manganese formate dihydrate (II) is around 110℃, and the absorption peak of melting is around 350℃. The analysis of these thermal results proves that the synthesized manganese formate dihydrate (II) contains two molecules of water of crystallization.

[0055] Figure 3 The image shown is a microscopic image of manganese formate dihydrate prepared in Example 12. Figure 3 It can be seen that the external characteristics of manganese formate (II) dihydrate under a microscope (magnification of 20*10) are that its crystal form is orthorhombic, its shape is cuboid, and the crystals are granular or crystalline powder with varying lengths and sizes.

[0056] Figure 4 The infrared spectrum of manganese(II) formate dihydrate prepared in Example 12 is shown. The infrared testing method is as follows: the test sample is mixed with potassium bromide at a mass ratio of approximately 1:100 and ground. After grinding, the sample is pressed into a tablet and then subjected to infrared spectroscopy testing in the range of 500–4000 cm⁻¹. -1 The wavenumber range was tested, and the number of scans was set to 4. Figure 4 It can be seen that manganese(II) formate dihydrate at 2887 cm⁻¹ -1 There exists a -CH- stretching vibration v(CH) at 1391 cm⁻¹. -1 The -COO- asymmetric stretching vibration νas(-COO-) at 1367 cm⁻¹ -1 The -COO- symmetric stretching vibration νs(-COO-) exhibits a peak shift at 1587 cm⁻¹ due to the influence of manganese ions on C=O. -1 The vibration is a stretching vibration at -C=O, at 744cm.-1 The deformation vibration δ(O-Mn-O) is located at O-Mn-O.

[0057] Figure 5 The infrared spectrum of potassium diformate prepared in Example 12 is shown below. Figure 5 It can be seen that the product has a diameter of 3412 cm. -1 The peak at 764cm -1 and 694cm -1 The two absorption peaks indicate the presence of associated -OH groups in the product; 2804 cm⁻¹ -1 and 2716cm -1 The two absorption peaks at 1379 cm⁻¹ represent the stretching vibrations of the CH group on the aldehyde group; -1 and 1346cm -1 The two peaks indicate that the product contains two carboxylate groups. In conclusion, this proves that the experimental product is potassium diformate.

[0058] The present invention also performed single-crystal dicrystalline diffraction analysis on the manganese(II) formate dihydrate prepared in Example 12, and the analysis results are shown in Table 2.

[0059] The analytical method was as follows: A single crystal of the compound of appropriate size was placed on a glass fiber, and data collection was performed using a D-MAX 2200VPC X-ray diffractometer. Graphite-monochromatic Mo-Kα rays (λ = 0.071023 nm) were used as the incident radiation, and data were collected at 193 K using a φ-ω scanning technique. No significant attenuation was observed during data collection. All calculations were performed using the SHELXL-97 program. The measured crystal structure was solved directly and corrected using the full-matrix least squares method.

[0060] Table 2 Crystal structure parameters of manganese(II) dihydrate

[0061]

[0062]

[0063] As shown in Table 2, manganese formate dihydrate (II) belongs to the orthorhombic crystal system, space group c of the P21 system, and has the structural formula (HCOO)2Mn·2H2O, containing two water molecules of crystallization.

[0064] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing potassium diformate, comprising the following steps: An aqueous solution of glyoxal and an aqueous solution of potassium permanganate are mixed to carry out a redox reaction; The product system obtained from the redox reaction was sequentially concentrated, crystallized, and filtered. The solid phase obtained after filtration was manganese formate dihydrate (II); The filtrate obtained from filtration is mixed with formic acid solution to carry out a synthesis reaction, yielding potassium diformate; The crystallization temperature is 1–5°C.

2. The method of claim 1, wherein, The volume concentration of the glyoxal aqueous solution is 8-12%.

3. The method according to claim 1, characterized in that, The concentration of the potassium permanganate aqueous solution is 0.15–0.2 mol / L.

4. The method according to any one of claims 1 to 3, characterized in that, The volume ratio of the aqueous solution of glyoxal to the aqueous solution of potassium permanganate is 1:

2.

5. The method according to claim 1, characterized in that, The mixing of the aqueous solutions of glyoxal and potassium permanganate is achieved by adding the aqueous solution of potassium permanganate dropwise into the aqueous solution of glyoxal.

6. The method according to claim 5, characterized in that, The dropping rate is 0.7–1.0 mL / min.

7. The method according to claim 1, characterized in that, The redox reaction is carried out under stirring conditions, and the stirring speed is 10-30 rpm.

8. The method according to claim 1 or 7, characterized in that, The redox reaction is carried out at a temperature of 20–40°C for 15–45 minutes.

9. The method according to claim 1, characterized in that, The volume after concentration is 1 / 5 to 6 of the volume of the system before concentration.

10. The method according to claim 1, characterized in that, The formic acid solution has a mass concentration of 80-90%.

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