A method for preparing a flaky potassium cyanate

Abstract

This invention discloses a method for preparing flake potassium cyanate. Urea and potassium borohydride are ground in an agate mortar at a mass ratio of 1:0.10–0.12 for 30–60 minutes to obtain a first substance. The first substance is then spread evenly in a covered crucible and placed in the center of a muffle furnace. A solid-state melting method is used to ensure a complete reaction. The muffle furnace is heated from room temperature at a rate of 3–5 °C per minute. ‑1 The mixture was heated at a rapid rate until it reached 500–600°C, and held for 120 minutes to obtain a second substance. After the reaction was complete, the second substance was allowed to cool naturally, then washed with anhydrous ethanol, centrifuged, dried, and cooled to room temperature to obtain flake potassium cyanate. This invention proposes a novel method for preparing flake potassium cyanate using a solid-state melting method. The process for preparing flake potassium cyanate is simple, completed in one step, and has good application prospects.

Description

A method for preparing flake potassium cyanate Technical Field

[0001] This invention belongs to the field of inorganic synthesis and discloses a method for preparing flake potassium cyanate. Background Technology

[0002] Potassium cyanate is a white crystalline solid. It is sparingly soluble in cold water, slightly soluble in ethanol, and reacts with potassium cyanamide and carbon dioxide at high temperatures in the absence of air. It is commonly used in organic synthesis and pharmaceuticals, and also as a herbicide and defoliant. Furthermore, it is widely used in glass manufacturing, metal surface hardening, and ceramic art. There are many methods for synthesizing potassium cyanate. An earlier method involved converting potassium cyanide into potassium cyanate using oxidizing agents such as oxygen, air, peroxides, or lead oxide. However, this method has disadvantages such as the high toxicity of the potassium cyanide used, hazardous operation, and low yield.

[0003] Currently, the United States and Japan have conducted the most research on the synthesis of potassium cyanide. Research from other European countries is mostly documented in patent reports. Reports from my country in this area are relatively few. According to literature, nitrogen-containing compounds used to synthesize potassium cyanide include urea, dicyandiamide, and melamine, while potassium salts include potassium carbonate, potassium hydroxide, and potassium nitrite. From the perspective of reaction phase, the main methods for preparing potassium cyanide include solid-state melting, absorption, liquid-phase reaction, and liquid-solid phase reaction. The solid-state melting method involves heating the reactants to a molten state and then cooling and solidifying to obtain the product. Using the solid-state melting method to prepare potassium cyanide results in good product dispersibility, simple operation, readily available raw materials, and good economic efficiency.

[0004] Current research on potassium cyanide products mainly focuses on improving its purity, with limited attention paid to the morphological characteristics of the prepared potassium cyanide. Considering that the morphology of potassium cyanide has a significant impact on its subsequent use, this invention proposes a method for preparing potassium cyanide with controllable morphology. Summary of the Invention

[0005] In view of the above shortcomings, compared with the traditional liquid-solid phase reaction method, this invention uses a solid-state melting method to synthesize potassium cyanate, which can be prepared with controllable morphology through simple grinding and calcination. The preparation process has low raw material cost, less time consumption, low operation difficulty, and simple process flow.

[0006] To achieve the above objectives, the present invention employs the following technical means:

[0007] This invention provides a method for preparing flake potassium cyanate, comprising the following specific steps:

[0008] S1: Grind urea and potassium borohydride in an agate mortar to obtain the first substance;

[0009] S2: Spread the first substance evenly in a covered crucible, place it in the center of a muffle furnace, and use a solid melting method to allow it to react fully to obtain the second substance;

[0010] S3: After the reaction is complete, the second substance is allowed to cool naturally, then washed, centrifuged, dried, and cooled to room temperature to obtain flake potassium cyanate.

[0011] Furthermore, the mass ratio of urea to potassium borohydride in S1 is 1:0.1 to 0.12.

[0012] Furthermore, the grinding time in the agate mortar described in S1 is 30–60 min;

[0013] Furthermore, the heating treatment described in S2 includes: heating in a muffle furnace from room temperature at a rate of 3–5°C per minute. -1 The temperature is increased at a certain rate until it reaches 500-600℃, and then held for 120 minutes.

[0014] Furthermore, in S3, anhydrous ethanol is used for washing and centrifugation several times, with the centrifuge speed being 4000-6000 rpm.

[0015] Furthermore, the drying conditions in S3 are: drying temperature: 60-80℃, drying time: 10-16h.

[0016] The present invention also discloses a flake potassium cyanate prepared according to any of the above preparation methods.

[0017] The beneficial effects of this invention are as follows:

[0018] A novel method for preparing flake-shaped potassium cyanate is proposed using a solid-state melting process. Compared to bulk potassium cyanate, flake-shaped potassium cyanate has a larger specific surface area and better dispersibility, which not only facilitates mass transfer but also provides a greater number of active sites. Therefore, flake-shaped potassium cyanate has greater potential in both technological applications and basic science. Attached Figure Description

[0019] Figure 1 shows the XRD pattern of potassium cyanide flakes.

[0020] Figure 2 shows the FT-IR spectrum of potassium cyanide flakes.

[0021] Figure 3 shows the SEM images of potassium cyanate, where a and b are SEM images of Example 1 at different magnifications, c and d are SEM images of Example 2 at different magnifications, and e and f are SEM images of Comparative Example 1 at different magnifications. Detailed Implementation

[0022] The present invention will be further described below with reference to specific embodiments, but the present invention is not limited to these specific embodiments.

[0023] Example 1

[0024] A method for preparing flake potassium cyanate includes the following specific steps:

[0025] First, weigh 5g of urea and 0.5g of potassium borohydride, mix them thoroughly, and grind them in an agate mortar for 30 minutes to ensure uniform mixing. Spread the ground urea and potassium borohydride powder evenly in a covered crucible, place it in the center of a muffle furnace, and heat the furnace from room temperature at a rate of 3.5℃ / min. Maintain the temperature at 550℃ for 120 minutes. After the reaction is complete, allow it to cool naturally. Wash the resulting solid with anhydrous ethanol, centrifuge three times at 4000rpm, and dry it in a 60℃ oven for 12 hours. The resulting sample is potassium cyanide flakes.

[0026] Example 2

[0027] A method for preparing flake potassium cyanate includes the following specific steps:

[0028] First, weigh 5g of urea and 0.6g of potassium borohydride, mix them thoroughly, and grind them in an agate mortar for 30 minutes to ensure uniform mixing. Spread the ground urea and potassium borohydride powder evenly in a covered crucible, place it in the center of a muffle furnace, and heat the furnace from room temperature at a rate of 4.5℃ / min. Maintain the temperature at 550℃ for 120 minutes. After the reaction is complete, allow it to cool naturally. Wash the resulting solid with anhydrous ethanol, centrifuge three times at 5000rpm, and dry it in a 60℃ oven for 12 hours. The resulting sample is potassium cyanide flakes.

[0029] Comparative Example 1

[0030] A method for preparing lumpy potassium cyanate includes the following specific steps:

[0031] First, weigh 5g of urea and 0.5g of potassium borohydride, mix them thoroughly, and grind them in an agate mortar for 15 minutes to ensure uniform mixing. Spread the ground urea and potassium borohydride powder evenly in a covered crucible, place it in the center of a muffle furnace, and heat the furnace from room temperature at a rate of 3.5℃ / min. Maintain the temperature at 450℃ for 120 minutes. After the reaction is complete, allow it to cool naturally. Wash the resulting solid with anhydrous ethanol, centrifuge three times, and dry it in a 60℃ oven for 12 hours. The resulting sample is lumpy potassium cyanate.

[0032] Experimental Example 1

[0033] Sample: Potassium cyanate flakes prepared in Example 1

[0034] Experimental Procedure: The crystal structure of the samples was analyzed using an X-ray diffractometer (D8 ADVANCE) manufactured by Rigaku Corporation, Japan. During testing, the sample simply needs to be placed on the sample stage. By comparing the measured diffraction peaks with standard cards, the crystalline phase contained in the sample was identified. Figure 1 shows the XRD pattern of the prepared plate-like potassium cyanate.

[0035] As shown in Figure 1, the characteristic diffraction peaks of the sample prepared in Example 1 at 2θ angles of 20.68°, 25.32°, 29.41°, 32.91°, 35.42°, 39.18°, 42.07°, 47.32°, 49.74°, 51.42°, 51.98°, and 54.42° correspond to the (110), (002), (200), (112), (211), (202), (220), (310), (222), (213), (004), and (312) crystal planes of potassium cyanate, respectively. These peaks are consistent with the standard card (JCPDS.NO.73-1515), proving that potassium cyanate was successfully prepared.

[0036] Experimental Example 2

[0037] Sample: Potassium cyanate flakes prepared in Example 1

[0038] Experimental Procedure: The structure, functional groups, and bonding status of plate-like potassium cyanate can be inferred from the peak positions of the infrared spectrum. The sample was analyzed using a Thermo Nicolet-6700 Fourier transform infrared spectrometer (USA), with a detection range of 4000 cm⁻¹. -1 ~400cm -1 The potassium cyanide flakes to be tested were mixed with KBr at a mass ratio of approximately 1:100, ground, and then compressed into tablets for testing. The FT-IR spectrum of the potassium cyanide flakes was obtained, and the results are shown in Figure 2.

[0039] As shown in Figure 2, 2200cm -1 ~2000cm -1 The absorption peak at this point is OCN -1 The characteristic absorption peak.

[0040] Experimental Example 3

[0041] Samples: Potassium cyanate flakes prepared in Example 1, potassium cyanate flakes prepared in Example 2, and potassium cyanate blocky prepared in Comparative Example 1.

[0042] Experimental procedure: The surface morphology of the flake potassium cyanate was observed using a scanning electron microscope (SEM) of the Carl Zeiss AG, Germany, model Ultra Plus. The results are shown in Figure 3.

[0043] Based on the results in Figure 3, a and b are SEM images of Example 1 at different magnifications, showing that the potassium cyanide morphology is irregular and has a sheet-like structure. c and d are SEM images of Example 2 at different magnifications, showing that the potassium cyanide morphology is obviously sheet-like and well-dispersed. e and f are SEM images of Comparative Example 1 at different magnifications, showing that the potassium cyanide morphology is a blocky porous structure.

[0044] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0045] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing flake potassium cyanate, comprising: S1: Grind urea and potassium borohydride in an agate mortar for 30-60 minutes to obtain the first substance; S2: Spread the first substance evenly in a covered crucible and place it in the center of a muffle furnace. Heat the muffle furnace from room temperature until it reaches 500-600°C and maintain the temperature for a certain time. Use the solid-state melting method to allow it to react fully and obtain the second substance. S3: After the reaction is complete, the second substance is allowed to cool naturally. Then, it is washed with anhydrous ethanol, centrifuged at 4000-6000 rpm, dried, and then cooled to room temperature to obtain flake potassium cyanate.

2. The preparation method according to claim 1, wherein: The mass ratio of urea to potassium borohydride in step S1 is 1:0.1~0.

12.

3. The preparation method according to claim 1, wherein: Step S2, heating the muffle furnace from room temperature, includes: heating at 3-5°C per minute. -1 Heat at a rising rate until it reaches 500~600℃, and hold for 120 minutes.

4. The preparation method according to claim 1, wherein: The drying conditions described in step S3 are: drying temperature: 60~80℃, drying time: 10~16h.

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