A preparation method of anti-caking potassium perchlorate

Abstract

The invention relates to the field of inorganic materials, and in particular to a method for preparing anti-caking potassium perchlorate. The method comprises the following steps: adding potassium perchlorate to be modified, polyvinyl alcohol and a polyionic liquid into a saturated potassium perchlorate solution, uniformly mixing the mixture, adjusting the pH value of the system to 3-5, adding a crosslinking agent and stirring the mixture for reaction, filtering the mixture and drying the mixture after the reaction is completed. Compared with commercially available potassium perchlorate, the potassium perchlorate prepared by the invention has an extremely low caking rate, a greatly reduced friction sensitivity and is safer during transportation and storage.

Description

Technical Field

[0001] The invention relates to the field of inorganic materials, and in particular to a method for preparing anti-caking potassium perchlorate. Background Art

[0002] Potassium perchlorate is an inorganic salt crystal and may clump during storage and use. This is mainly because it is highly hygroscopic and easily absorbs moisture in the air, causing surface dissolution and recrystallization to form crystal bridges, which in turn causes agglomeration.

[0003] At present, there are roughly two methods for selecting anti-caking additives for inorganic salt crystals at home and abroad. One is to use some inert powders to separate the surface of the particles to prevent the contact area between the particles from being too large and causing a bridging effect. However, if the dosage of the additive is too small, the anti-caking effect is poor. If the dosage of the additive is too large, the purity of the finished product is difficult to control within the product quality standard, that is, the impurity content exceeds the standard. The second is to add polymers or surfactants to prevent agglomeration by changing the surface properties of the inorganic salt crystals or forming a polymer film. Currently, there is relatively little research on this method. Summary of the invention

[0004] Purpose of the invention: In view of the above technical problems, the present invention provides a method for preparing anti-caking potassium perchlorate.

[0005] The technical solutions adopted are as follows:

[0006] A preparation method of anti-caking potassium perchlorate:

[0007] Add the potassium perchlorate to be modified, polyvinyl alcohol and polyionic liquid to a saturated potassium perchlorate solution, mix well and adjust the pH of the system to 3-5, then add a crosslinking agent and stir to react, filter and dry after the reaction is completed.

[0008] Furthermore, the preparation method of the polyionic liquid is as follows:

[0009] The ionic liquid undergoes free radical polymerization under the action of a free radical initiator, and the obtained polymerization product is filtered out and then dried.

[0010] Furthermore, the anion of the ionic liquid is any one of a halogen ion, a tetrafluoroborate ion, a hexafluorophosphate ion, a bis(trifluoromethanesulfonyl)imide ion, and a p-toluenesulfonate ion.

[0011] Furthermore, the cationic structure of the ionic liquid is as follows:

[0012] ;

[0013] Wherein, n is a positive integer, n≥5.

[0014] Furthermore, the free radical initiator is azobisisobutyronitrile and / or azobisisoheptanenitrile.

[0015] Furthermore, the cross-linking agent is glutaraldehyde.

[0016] Furthermore, the mass ratio of the polyvinyl alcohol, the polyionic liquid and the cross-linking agent is 70-100:10-50:1-5.

[0017] Furthermore, ultrasonic oscillation treatment is applied while stirring the reaction.

[0018] Furthermore, the temperature during the stirring reaction is 30-60°C.

[0019] Furthermore, the drying temperature is ≤100°C.

[0020] Beneficial effects of the present invention:

[0021] The invention provides a preparation method of anti-caking potassium perchlorate. Polyvinyl alcohol can be coated on the surface of potassium perchlorate to form a film, and a three-dimensional network structure is formed through cross-linking with a cross-linking agent, so that the strength of the film layer is enhanced, so that potassium perchlorate particles will not damage the film layer when encountering temperature changes, extrusion, moisture and other conditions, thereby avoiding adhesion between particles and having a good anti-caking effect. The polyionic liquid has both the characteristics of a surfactant and a self-lubricating property, and the amino group in its structure can also undergo a cross-linking reaction with a cross-linking agent. Under the combined effect of these factors, the existing potassium perchlorate can be modified to have a better anti-caking performance. Compared with commercially available potassium perchlorate, the potassium perchlorate prepared by the invention has an extremely low caking rate, and the friction sensitivity is greatly reduced, so that it is safer during transportation and storage. DETAILED DESCRIPTION

[0022] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially. The techniques not mentioned in the present invention are all referenced to the prior art. Unless otherwise specified, the following examples and comparative examples are parallel experiments, using the same processing steps and parameters. Example 1

[0023] A preparation method of anti-caking potassium perchlorate:

[0024] To 5000 ml of saturated aqueous potassium perchlorate solution, add 200 g of commercially available potassium perchlorate (particle size 50-100 μm), first add 80 g of polyvinyl alcohol and mix well, then dissolve 20 g of polyionic liquid in 500 ml of DMF and add, mix well and adjust the pH of the system to 4 with hydrochloric acid, then dissolve 4 g of cross-linking agent glutaraldehyde in 100 ml of DMF and slowly add dropwise to the mixed system, stir the reaction solution under ultrasonic oscillation and 35°C water bath conditions for 60 min, return to room temperature after the reaction is completed, filter, and dry the obtained product in an oven at 60°C for 24 h.

[0025] Wherein, the preparation method of polyionic liquid is as follows:

[0026] ;

[0027] Dissolve 50 g of 3-aminooctyl-1-vinylimidazolium chloride and 1 g of azobisisobutyronitrile in appropriate amounts of chloroform to obtain solution A and solution B, respectively. Under nitrogen protection, slowly drop solution B into solution A with constant stirring. Heat to reflux for 6 hours and then return to room temperature. Filter out the resulting precipitate and dry it. Example 2

[0028] A preparation method of anti-caking potassium perchlorate:

[0029] To 5000 ml of saturated aqueous potassium perchlorate solution, add 200 g of commercially available potassium perchlorate (particle size 50-100 μm), first add 80 g of polyvinyl alcohol and mix well, then dissolve 20 g of polyionic liquid in 500 ml of DMF and add, mix well, adjust the pH of the system to 4 with hydrochloric acid, then dissolve 4 g of cross-linking agent glutaraldehyde in 100 ml of DMF and slowly add dropwise to the mixed system, stir the reaction solution under ultrasonic oscillation and 35°C water bath conditions for 60 minutes, return to room temperature after the reaction, filter, and dry the obtained product in an oven at 60°C for 24 hours.

[0030] Wherein, the preparation method of polyionic liquid is as follows:

[0031] ;

[0032] Dissolve 50 g of 3-aminooctyl-1-vinylimidazole tetrafluoroborate and 1 g of azobisisobutyronitrile in appropriate amounts of chloroform to obtain solution A and solution B, respectively. Under nitrogen protection, slowly drop solution B into solution A with constant stirring. Heat to reflux for 6 h and then return to room temperature. Filter out the resulting precipitate and dry it. Example 3

[0033] A preparation method of anti-caking potassium perchlorate:

[0034] To 5000 ml of saturated aqueous potassium perchlorate solution, add 200 g of commercially available potassium perchlorate (particle size 50-100 μm), first add 80 g of polyvinyl alcohol and mix well, then dissolve 20 g of polyionic liquid in 500 ml of DMF and add, mix well, adjust the pH of the system to 4 with hydrochloric acid, then dissolve 4 g of cross-linking agent glutaraldehyde in 100 ml of DMF and slowly add dropwise to the mixed system, stir the reaction solution under ultrasonic oscillation and 35°C water bath conditions for 60 minutes, return to room temperature after the reaction, filter, and dry the obtained product in an oven at 60°C for 24 hours.

[0035] Wherein, the preparation method of polyionic liquid is as follows:

[0036] ;

[0037] Dissolve 50 g of 3-aminooctyl-1-vinylimidazole hexafluorophosphate and 1 g of azobisisobutyronitrile in appropriate amounts of chloroform to obtain solution A and solution B, respectively. Under nitrogen protection, slowly drop solution B into solution A with constant stirring. Heat to reflux for 6 h and then return to room temperature. Filter out the resulting precipitate and dry it. Example 4

[0038] A preparation method of anti-caking potassium perchlorate:

[0039] To 5000 ml of saturated aqueous potassium perchlorate solution, add 200 g of commercially available potassium perchlorate (particle size 50-100 μm), first add 90 g of polyvinyl alcohol and mix well, then dissolve 10 g of polyionic liquid in 500 ml of DMF and add, mix well, adjust the pH of the system to 4 with hydrochloric acid, then dissolve 4 g of cross-linking agent glutaraldehyde in 100 ml of DMF and slowly add dropwise to the mixed system, stir the reaction solution under ultrasonic oscillation and 35°C water bath conditions for 60 minutes, return to room temperature after the reaction, filter, and dry the obtained product in an oven at 60°C for 24 hours.

[0040] Wherein, the preparation method of polyionic liquid is as follows:

[0041] ;

[0042] Dissolve 50 g of 3-aminooctyl-1-vinylimidazolium chloride and 1 g of azobisisobutyronitrile in appropriate amounts of chloroform to obtain solution A and solution B, respectively. Under nitrogen protection, slowly drop solution B into solution A with constant stirring. Heat to reflux for 6 hours and then return to room temperature. Filter out the resulting precipitate and dry it. Example 5

[0043] A preparation method of anti-caking potassium perchlorate:

[0044] To 5000 ml of saturated aqueous potassium perchlorate solution, add 200 g of commercially available potassium perchlorate (particle size 50-100 μm), first add 70 g of polyvinyl alcohol and mix well, then dissolve 30 g of polyionic liquid in 500 ml of DMF and add, mix well, adjust the pH of the system to 4 with hydrochloric acid, then dissolve 4 g of cross-linking agent glutaraldehyde in 100 ml of DMF and slowly add dropwise to the mixed system, stir the reaction solution under ultrasonic oscillation and 35°C water bath conditions for 60 minutes, return to room temperature after the reaction, filter, and dry the obtained product in an oven at 60°C for 24 hours.

[0045] Wherein, the preparation method of polyionic liquid is as follows:

[0046] ;

[0047] Dissolve 50 g of 3-aminooctyl-1-vinylimidazolium chloride and 1 g of azobisisobutyronitrile in appropriate amounts of chloroform to obtain solution A and solution B, respectively. Under nitrogen protection, slowly drop solution B into solution A with constant stirring. Heat to reflux for 6 hours and then return to room temperature. Filter out the resulting precipitate and dry it.

[0048] Comparative Example 1: basically the same as Example 1, except that no polyionic liquid is added.

[0049] A preparation method of anti-caking potassium perchlorate:

[0050] To 5000 ml of saturated aqueous potassium perchlorate solution, add 200 g of commercially available potassium perchlorate (particle size 50-100 μm), first add 80 g of polyvinyl alcohol and mix well, then add 500 ml of DMF, mix well and adjust the pH of the system to 4 with hydrochloric acid, dissolve 4 g of glutaraldehyde, a cross-linking agent, in 100 ml of DMF and slowly add it dropwise to the mixed system, stir the reaction solution under ultrasonic oscillation and 35°C water bath conditions for 60 minutes, return to room temperature after the reaction, filter, and dry the obtained product in an oven at 60°C for 24 hours.

[0051] Comparative Example 2: basically the same as Example 1, except that no polyionic liquid and cross-linking agent glutaraldehyde are added.

[0052] A preparation method of anti-caking potassium perchlorate:

[0053] Add 200g of commercially available potassium perchlorate (particle size 50-100μm) to 5000ml of saturated potassium perchlorate aqueous solution, first add 80g of polyvinyl alcohol and mix well, then add 500ml of DMF, mix well, adjust the pH of the system to 4 with hydrochloric acid, then slowly add 100ml of DMF dropwise to the mixed system, stir the reaction solution under ultrasonic oscillation and 35℃ water bath conditions for 60min, return to room temperature after the reaction, filter, and dry the product in an oven at 60℃ for 24h.

[0054] Performance Test:

[0055] ① The potassium perchlorate prepared in Examples 1-5 and Comparative Example 1-2 and commercially available potassium perchlorate were respectively pressed into cylindrical samples of φ100 mm×100 mm at 3 MPa;

[0056] Place the cylindrical sample in an environment with a humidity of 75% and a temperature of 25°C to absorb moisture for 30 days, then let it fall freely at a height of 10m above the ground, and then pass through a 40-mesh sieve to calculate the agglomeration rate η;

[0057] ;

[0058] m1 is the sieve residue mass, m0 is the sample mass;

[0059] ② The potassium perchlorate in Examples 1-5 and Comparative Examples 1-2 and commercially available potassium perchlorate were used as test samples, respectively. A friction sensitivity test was performed using a friction sensitivity meter according to the method in GJB770B-2005. The test pressure was 3.92 MPa and the swing angle was 90°. During the test, any sample that showed any of the following phenomena, such as discoloration, odor, smoke, explosion sound, or ablation marks on the surface of the impact column, was judged to be exploded, otherwise it was judged to be non-exploded. Each group of samples was measured 25 times in parallel, and the measurement results were expressed as explosion percentage.

[0060] The test results are shown in Table 1 below:

[0061] Table 1:

[0062] ;

[0063] It can be seen from Table 1 above that the potassium perchlorate prepared by the present invention has an extremely low agglomeration rate compared with commercially available potassium perchlorate, and the friction sensitivity is significantly reduced.

[0064] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing anti-caking potassium perchlorate, It is characterized in that Add the potassium perchlorate to be modified, polyvinyl alcohol and polyionic liquid to the saturated potassium perchlorate solution, mix well and adjust the pH of the system to 3-5, then add the crosslinking agent and stir to react, filter and dry after the reaction is completed; The preparation method of the polyionic liquid is as follows: The ionic liquid undergoes free radical polymerization under the action of a free radical initiator, and the obtained polymerization product is filtered out and then dried; The anion of the ionic liquid is any one of a halogen ion, a tetrafluoroborate ion, a hexafluorophosphate ion, a bis(trifluoromethanesulfonyl)imide ion, and a p-toluenesulfonate ion; The cation structure of the ionic liquid is shown below: ； Wherein, n is a positive integer, n=8; The free radical initiator is azobisisobutyronitrile and / or azobisisoheptanenitrile; The cross-linking agent is glutaraldehyde.

2. The method for preparing the anti-caking potassium perchlorate according to claim 1, It is characterized in that The mass ratio of the polyvinyl alcohol, the polyionic liquid and the cross-linking agent is 70-100:10-50:1-5.

3. The method for preparing the anti-caking potassium perchlorate according to claim 1, It is characterized in that The reaction was stirred while ultrasonic vibration was applied.

4. The method for preparing the anti-caking potassium perchlorate according to claim 1, It is characterized in that The temperature during the stirring reaction is 30-60°C.

5. The method for preparing the anti-caking potassium perchlorate according to claim 1, It is characterized in that Drying temperature ≤100℃.

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