Preparation method of high-purity octahydrotriborate strontium salt

Abstract

The invention provides a preparation method of high-purity octahydrogen triborate strontium salt. The method comprises the following steps: step 1, mixing and dissolving an octahydrogen triboron sodium salt crude product and water; 2, after dissolving, filtering insoluble substances by using neutral filter paper to obtain an octahydrogen triboron sodium salt crude product solution; step 3, enabling the octahydro triboron sodium salt crude product solution to pass through anion exchange resin, and adsorbing anions B11H14 <-> onto the anion exchange resin; 4, a sulfuric acid solution is used as a resolving agent for leaching and resolving, anion B11H14 <-> is eluted into the solution, and a pure octahydrotriboric acid water solution is obtained; and step 5, dropwise adding a strontium hydroxide aqueous solution into the pure octahydrotriboric acid aqueous solution obtained in the step 4 until the solution is neutral, separating out a strontium octahydrotriborate finished product, filtering, and drying to obtain the strontium octahydrotriborate. The product obtained by the preparation method disclosed by the invention has the characteristics of high purity, simple process flow, economy, environmental protection and suitability for industrial production, and the comprehensive yield can reach 95.0 wt.%.

Description

Technical Field

[0001] The invention belongs to the technical field of solid propellants and relates to borates, and in particular to a method for preparing high-purity strontium octahydrogentriborate. Background Art

[0002] Octahydrogen triborate has important application value in the field of solid missile propellants as an intermediate in the preparation of decaborane and a propellant burning rate regulating component. However, the high cost caused by the difficulty in purification seriously restricts its application scale. With the development of the propellant industry, its low-cost purification method has important prospects.

[0003] The purification method of octahydrogen triborate in the prior art mainly utilizes the ion exchange and recrystallization of its ammonium salt. When a substance solidifies from a liquid part to a solid state, due to the different solubility of impurities in its liquid and solid states, the impurity concentration in the solid state is often lower than the impurity concentration in the liquid state. This phenomenon is called fractionation. The substance can be purified by utilizing this phenomenon. However, since the solubility of octahydrogen triborate ammonium salt is not large and the dissolution curve is not steep enough, the recrystallization method is very inefficient, the purification effect is not ideal, and the single purification efficiency is not high, and multiple recrystallizations are required to achieve the required purity. In this way, the yield after purification will be greatly reduced, and a large amount of crystallization liquid will also be increased. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for preparing high-purity strontium octahydrogentriborate, so as to solve the technical problem that the preparation method in the prior art is difficult to balance the purification efficiency and yield.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems:

[0006] A method for preparing high-purity strontium octahydrogen triborate, the method comprising the following steps:

[0007] Step 1, mixing and dissolving crude sodium octahydrogen triboron salt and water;

[0008] Step 2, after dissolution, filter the insoluble matter with neutral filter paper to obtain a crude solution of sodium octahydrogen triboron salt;

[0009] Step 3: passing the crude sodium octahydrogen triboron salt solution through an anion exchange resin to obtain anions B in the crude sodium octahydrogen triboron salt solution. 11 H 14 - Adsorbed onto anion exchange resin, and the saturated anion exchange resin was washed with deionized water;

[0010] Step 4: Using sulfuric acid solution as an analytical agent, washing and analyzing, the anion B adsorbed by the anion exchange resin 11 H14 - The anion exchange resin is then washed with deionized water to obtain a pure aqueous solution of octahydrotriboric acid, and the anion exchange resin is recovered for standby use;

[0011] Step 5, adding strontium hydroxide aqueous solution to the pure octahydrotriboric acid aqueous solution obtained in step 4 until the solution becomes neutral to precipitate strontium octahydrotriborate salt product, filtering and drying to obtain strontium octahydrotriborate salt.

[0012] The present invention also has the following technical features:

[0013] Preferably, in step 1, the crude sodium octahydrogen triboron salt and deionized water are mixed and dissolved in a mass ratio of 1:(5-15).

[0014] Further preferably, in step 1, the crude sodium octahydrogen triboron salt and deionized water are mixed and dissolved in a mass ratio of 1:15.

[0015] Preferably, in step three, the crude sodium octahydrogen triboron salt solution is passed through an anion exchange resin at a rate of 5 to 20 L / h.

[0016] Further preferably, in step three, the crude sodium octahydrogen triboron salt solution is passed through an anion exchange resin at a rate of 10 L / h.

[0017] Preferably, in step 4, elution and analysis are performed at a flow rate of 5 to 20 L / h.

[0018] Further preferably, in step 4, elution and analysis are performed at a flow rate of 10 L / h.

[0019] Compared with the prior art, the present invention has the following technical effects:

[0020] (I) The product obtained by the preparation method of the present invention has high purity, simple process flow, economy and environmental protection, and is suitable for industrial production. The comprehensive yield can reach 95.0wt.%.

[0021] (II) The preparation method of the present invention uses an anionic ion exchange resin to remove impurities, and then purifies by neutralization and crystallization. The method is easy to operate and convenient to control the quantitative purification. Undecanoic acid tetradecanoate can be purified from a high-purity reagent to a high purity of 99.5wt.%. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the NMR boron spectrum of strontium octahydrogentriborate.

[0023] The specific contents of the present invention are further explained in detail below in conjunction with embodiments. DETAILED DESCRIPTION

[0024] It should be noted that, unless otherwise specified, all materials and equipment in the present invention are those known in the art.

[0025] The invention provides a method for preparing high-purity strontium octahydrogen triborate. The method comprises the following steps: firstly, a crude sodium octahydrogen triborate is dissolved and filtered to obtain a crude sodium octahydrogen triborate solution; then, the crude sodium octahydrogen triborate solution is adsorbed and analyzed on an anion exchange resin to obtain a pure aqueous solution of octahydrogen triboric acid; and finally, an aqueous solution of strontium hydroxide is added dropwise to the aqueous solution of octahydrogen triborate to obtain the strontium octahydrogen triborate.

[0026] In the present invention, the purity of crude sodium octahydrotriborate is 95.0wt.%; the anion exchange resin is the known acrylic acid-based strongly basic anion exchange resin D213.

[0027] The strontium octahydrotriborate salt of the invention is used as an intermediate for preparing decaborane.

[0028] The strontium octahydrogen triborate salt of the invention is used as a propellant burning rate regulating component.

[0029] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0030] Example:

[0031] This embodiment provides a method for preparing high-purity strontium octahydrogen triborate, which is carried out according to the following steps:

[0032] Step 1: Mix and dissolve 500 g crude sodium octahydrogen triboron salt and deionized water in a mass ratio of 1:15.

[0033] Step 2: After dissolution, filter the insoluble matter with neutral filter paper to obtain 10L of a clear crude solution of sodium octahydrogen triboron salt.

[0034] Step 3: Pass the filtered solution through an anion exchange resin with a loading capacity of 30 kg at a rate of 10 L / h. - Adsorbed onto anion exchange resin, the saturated anion exchange resin is washed with deionized water while removing impurities that are not adsorbed.

[0035] Step 4: eluting and analyzing with a 1M sulfuric acid solution at a flow rate of 10L / h, with a total elution volume of 10L. The anion B3H8 adsorbed by the anion exchange resin - The anion exchange resin was eluted into the solution and then washed with 10 L of deionized water to obtain a pure aqueous solution of octahydrotriboric acid. The anion exchange resin was recovered for standby use.

[0036] Step 5: Add strontium hydroxide (1M) aqueous solution to the pure octahydrotriboric acid aqueous solution until the solution becomes neutral to precipitate the strontium octahydrotriborate salt product, filter and dry in an oven to obtain 638.9 g of pure strontium octahydrotriborate salt with a purity of 99.5 wt.%, and a yield of 95.0 wt.%.

[0037] The characterization data of the product obtained by the present invention are as follows Figure 1 As shown, from Figure 1 It can be seen that the product obtained in this example is the target compound strontium octahydrogen triborate.

Claims

1. A method for preparing high-purity strontium octahydrogen triborate, characterized in that: The method comprises the following steps: Step 1, mixing and dissolving crude sodium octahydrogen triboron salt and water; Step 2, after dissolution, filter the insoluble matter with neutral filter paper to obtain a crude solution of sodium octahydrogen triboron salt; Step 3: passing the crude sodium octahydrogen triboron salt solution through an anion exchange resin to obtain anions B in the crude sodium octahydrogen triboron salt solution. 11 H 14 - Adsorbed onto anion exchange resin, and the saturated anion exchange resin was washed with deionized water; Step 4: Using sulfuric acid solution as an analytical agent, washing and analyzing, the anion B adsorbed by the anion exchange resin 11 H 14 - The anion exchange resin is then washed with deionized water to obtain a pure aqueous solution of octahydrotriboric acid, and the anion exchange resin is recovered for standby use; Step 5, adding strontium hydroxide aqueous solution to the pure octahydrotriboric acid aqueous solution obtained in step 4 until the solution becomes neutral to precipitate strontium octahydrotriborate salt product, filtering and drying to obtain strontium octahydrotriborate salt.

2. The method for preparing high-purity strontium octahydrogen triborate according to claim 1, characterized in that: In step 1, crude sodium octahydrogen triboron salt and deionized water are mixed and dissolved in a mass ratio of 1: (5-15).

3. The method for preparing high-purity strontium octahydrogen triborate according to claim 2, characterized in that: In step 1, crude sodium octahydrogen triboron salt and deionized water are mixed and dissolved in a mass ratio of 1:

15.

4. The method for preparing high-purity strontium octahydrogen triborate according to claim 1, characterized in that: In step 3, the crude sodium octahydrogen triboron salt solution is passed through an anion exchange resin at a rate of 5 to 20 L / h.

5. The method for preparing high-purity strontium octahydrogen triborate according to claim 4, characterized in that: In step 3, the crude sodium octahydrogen triboron salt solution is passed through an anion exchange resin at a rate of 10 L / h.

6. The method for preparing high-purity strontium octahydrogen triborate according to claim 1, characterized in that: In step 4, elution and analysis are performed at a flow rate of 5 to 20 L / h.

7. The method for preparing high-purity strontium octahydrogen triborate according to claim 6, characterized in that: In step 4, elution and analysis were performed at a flow rate of 10 L / h.

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