An ethoxylated column [6] aromatic hydrocarbon microcrystal and its application in recovering nitroazide

Abstract

The present invention discloses an ethoxylated [6] aromatic hydrocarbon microcrystal and its application in recovering nitroaniline. The present invention obtains ethoxylated [6] aromatic hydrocarbon solid microcrystals by a cooling crystallization-vacuum drying method. The ethoxylated [6] aromatic hydrocarbon microcrystals are dispersed in waste containing nitroaniline to achieve adsorption of nitroaniline by the ethoxylated [6] aromatic hydrocarbon solid powder. The adsorption method of the present invention is simple to operate, safe and reliable, and has high adsorption efficiency. The ethoxylated [6] aromatic hydrocarbon solid powder is easily obtainable and reusable.

Description

Technical Field

[0001] The present invention relates to an adsorption technology for energetic compounds, and in particular to an ethoxylated columnar[6] aromatic hydrocarbon solid microcrystal and its application in the adsorption of nitroazide. Background Art

[0002] Nitrazolamine (chemical name: 1,5-diazide-3-nitroazapentane, abbreviation: DIANP) is a new energetic plasticizer containing azide and nitramine groups and a nitrogen content of up to 56%. It has the advantages of high energy, low explosion temperature, high burning rate, low molecular weight of gas, and strong plasticizing ability for nitrocellulose.

[0003] During the synthesis, post-processing and application of nitroazide, it is inevitable to produce a large amount of waste containing nitroazide (also referred to as waste in this article), which is highly toxic and highly dangerous. The discharge of nitroazide waste causes serious damage to the ecological environment and human health.

[0004] Traditional methods for treating energetic wastewater mainly include incineration, activated carbon adsorption and other methods, which have defects such as low wastewater treatment efficiency and long cycle. Therefore, it is of great significance to develop a new azidonitramine adsorption method.

[0005] Host-guest chemistry is a major branch of supramolecular chemistry. Over the past 50 years, a number of important host molecules have been developed, including crown ethers, cyclodextrins, calixarenes, cucurbiturils, pillararenes, and molecular clamps. Pillararenes, as pillar-like supramolecular host compounds, possess extensive host-guest recognition capabilities and hold promising application prospects in adsorption and separation.

[0006] For example, in the paper "Separation of Aromatics / Cyclic Aliphatics by Nonporous Adaptive Pillarene Crystals" (Angew. Chem. Int. Ed. 2018, 57, 12845–12849), ethoxylated column [5] aromatic hydrocarbons (EtP5) and ethoxylated column [6] aromatic hydrocarbons (EtP6) crystals were used to achieve highly selective separation of toluene and methylcyclohexane. In the solid-gas adsorption experiment of a toluene / methylcyclohexane mixture on EtP5 crystals, the separation efficiency of toluene reached 98.8%, while the separation efficiency of methylcyclohexane on a toluene / methylcyclohexane mixture on EtP6 crystals reached 99.2%. Summary of the Invention

[0007] In view of the defects or shortcomings of the prior art, the present invention provides an ethoxylated columnar[6] aromatic hydrocarbon microcrystal.

[0008] To this end, the present invention provides a method for preparing ethoxylated [6] aromatic hydrocarbon microcrystals, comprising: filtering a saturated organic solvent solution of ethoxylated [6] aromatic hydrocarbon at 40-50° C. while hot, allowing the filtrate to stand at room temperature, and vacuum drying the precipitated solid to obtain ethoxylated [6] aromatic hydrocarbon microcrystals; the structural formula of the ethoxylated [6] aromatic hydrocarbon is:

[0009]

[0010] An optional solution is that the organic solvent is a mixture of ethyl acetate and petroleum ether in any proportion.

[0011] An optional solution is that the volume ratio of ethoxylated column[6] aromatic hydrocarbon to organic solvent is 1:20-40.

[0012] The optional option is to let it stand for 12 to 36 hours.

[0013] The present invention discloses an application of ethoxylated [6] aromatic hydrocarbon microcrystals for recovering nitroazide from waste. The specific recovery method comprises: adding the ethoxylated [6] aromatic hydrocarbon microcrystals to waste, mixing at a temperature of 20 to 40° C., and allowing the ethoxylated [6] aromatic hydrocarbon to adsorb the nitroazide from the waste; and then utilizing an organic solvent for decomposition to recover the ethoxylated [6] aromatic hydrocarbon and nitroazide. The organic solvent is further selected from dichloromethane and methanol.

[0014] The present invention slowly crystallizes ethoxylated [6] aromatic hydrocarbons in a hot saturated solution, causing the ethoxylated [6] aromatic hydrocarbon molecules to be densely packed together to form a microcrystalline structure. Due to the intrinsic cavities of the ethoxylated [6] aromatic hydrocarbon molecules, the formed crystal structure contains abundant channels, which can drive the encapsulation of nitroazide molecules within the cavities of the ethoxylated [6] aromatic hydrocarbons, thereby achieving efficient adsorption of nitroazide by the ethoxylated [6] aromatic hydrocarbons. Compared with the raw material ethoxylated [6] aromatic hydrocarbons, the ethoxylated [6] aromatic hydrocarbon microcrystalline structure has better crystallinity, and the ethoxylated [6] aromatic hydrocarbon molecules are more densely packed together. Safe and efficient adsorption of nitroazide can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 UV-visible absorption spectra of aqueous nitroazide solutions with different concentrations;

[0016] Figure 2 This is the UV absorption standard curve of nitroamine aqueous solution. DETAILED DESCRIPTION

[0017] Unless otherwise specified, the scientific and technical terms used herein are understood by persons of ordinary skill in the relevant art. It should be noted that, based on the present invention, those skilled in the art may optimize the methods of the present invention, including but not limited to reaction temperature, duration, the ratio of the various reaction raw materials, the order and method of addition of the components, and the mixing method, to achieve the effects of the present invention. Examples include, but are not limited to, the specific technical means provided herein.

[0018] The present invention will be further described below in conjunction with the accompanying drawings and specific examples. It should be understood that these examples are intended to illustrate the present invention and are not intended to limit the scope of the invention. The operating methods in the following examples where no specific conditions are specified are generally performed under conventional conditions or as recommended by the manufacturer.

[0019] In the actual production of nitroaniline, waste containing nitroaniline is generated during the synthesis and post-processing process. In the following examples, an aqueous solution of nitroaniline is used to simulate a simulant of waste containing nitroaniline. This simulant is often used by those skilled in the art to study the adsorption effect of nitroaniline. Among them, the molecular formula of nitroaniline is

[0020] The "recovery" mentioned in the present invention refers to the adsorption of nitroaniline from the waste containing nitroaniline, and then the release of nitroaniline by desorption, thereby realizing the recovery of nitroaniline from the waste containing nitroaniline.

[0021] The raw material ethoxylated pillar[6]arene used in the following examples was synthesized in the laboratory (the synthesis method is described in the journal article A Facile and Efficient Preparation of Pillararenes and a Pillarquinone).

[0022] Example 1:

[0023] 10.0 g of ethoxylated column [6] aromatic hydrocarbon was dispersed in a mixed solution of ethyl acetate and petroleum ether in a volume ratio of 1:20, and the temperature was raised to 40°C to prepare a hot saturated solution. The solution was filtered while hot, and the filtrate was cooled to room temperature and allowed to stand for 12 hours. The ethoxylated column [6] aromatic hydrocarbon solid precipitated and was transferred to a vacuum drying oven, heated to 60°C, and vacuum dried for 6 hours. After vacuum drying, the mass of powdered ethoxylated column [6] aromatic hydrocarbon microcrystals was 4.7 g.

[0024] Example 2:

[0025] This embodiment differs from embodiment 1 in that the filtrate is cooled to room temperature and then allowed to stand for 24 hours; the mass of the substance after vacuum drying is 6.4 g.

[0026] Example 3:

[0027] This embodiment differs from embodiment 1 in that the filtrate is cooled to room temperature and then allowed to stand for 36 hours; the mass of the substance after vacuum drying is 6.9 g.

[0028] Example 4:

[0029] This embodiment differs from embodiment 2 in that the volume ratio of ethyl acetate to petroleum ether is 1:40; and the mass of the substance after vacuum drying is 7.3 g.

[0030] Example 5:

[0031] This embodiment differs from embodiment 4 in that the temperature is raised to 50° C., a hot saturated solution is prepared, the solution is filtered while hot, the filtrate is cooled to room temperature and then allowed to stand for 36 hours, and the mass of the substance after vacuum drying is 8.1 g.

[0032] Example 6:

[0033] 1.0 g of ethoxylated column [6] aromatic hydrocarbon solid microcrystals prepared in Example 1 were dispersed in a 1.0×10 -3 mol / L aqueous solution of nitroaniline was stirred at constant temperature for 4 h at 20 ° C to achieve the adsorption of nitroaniline by ethoxy column [6] aromatic hydrocarbon solid powder. The concentration of nitroaniline in the solution after adsorption was 3.1×10 -4 mol / L.

[0034] The UV absorption graphs of aqueous solutions of nitroazide with different concentrations are shown in Figure 2. Figure 1 As shown, measure the absorbance value at the maximum absorption wavelength, draw the standard working curve with concentration as the horizontal axis and absorbance as the vertical axis, and the result is as follows Figure 2 According to the UV absorption standard curve equation of nitroazide aqueous solution and the UV absorption spectrum of the adsorbed solution, the concentration of nitroazide in the adsorbed solution was determined.

[0035] Example 7:

[0036] 1.0 g of ethoxylated column [6] aromatic hydrocarbon solid powder prepared in Example 1 was dispersed in a 1.0×10 -3 mol / L aqueous solution of nitroaniline was stirred at constant temperature for 6 h, 10 h, and 12 h at 20 °C to achieve the adsorption of nitroaniline by ethoxylated column [6] aromatic hydrocarbon solid powder. The concentration of nitroaniline in the solution after adsorption was 1.8×10 -4 mol / L, 4.3×10 -5 mol / L、3.9×10 -5 mol / L.

[0037] Example 8:

[0038] 1.0 g of ethoxylated column [6] aromatic hydrocarbon solid powder prepared in Example 1 was dispersed in a 1.0×10 -3mol / L aqueous solution of nitroaniline was stirred at constant temperature for 6 h at 40 ° C to achieve the adsorption of nitroaniline by ethoxy column [6] aromatic hydrocarbon solid powder. The concentration of nitroaniline in the solution after adsorption was 2.6×10 -4 mol / L.

[0039] Comparative Example:

[0040] The difference between this comparative example and Example 8 is that the same amount of raw material ethoxylated column [6] aromatic hydrocarbon was used to adsorb the aqueous solution of nitroaniline for 6 hours, and the same detection method was used. The detection results were: the concentration of nitroaniline in the solution after adsorption was 6.2×10 -4 mol / L.

[0041] Example 9:

[0042] In this embodiment, dichloromethane is added to the solid microcrystalline ethoxylated [6]arene loaded with nitroazide in Example 8 until it is completely dissolved. Then, 5 volumes of methanol are added to precipitate the ethoxylated [6]arene. The precipitate is filtered, and the filtrate and solid are collected separately. The filtrate is concentrated by rotary evaporation to obtain liquid nitroazide. The purity of the liquid nitroazide is greater than 92% as determined by H-NMR spectroscopy. After drying, the solid is determined by H-NMR spectroscopy to be ethoxylated [6]arene with a purity greater than 98%.

Claims

1. Application of ethoxylated [6] aromatic hydrocarbon microcrystals for recovering nitroamine from waste; the preparation method of the ethoxylated [6] aromatic hydrocarbon microcrystals comprises: A saturated first organic solvent solution of ethoxylated column[6]arene at 40-50°C is filtered while hot, the filtrate is allowed to stand at room temperature, and the precipitated solid is vacuum dried to obtain ethoxylated column[6]arene microcrystals; the structural formula of the ethoxylated column[6]arene is: 。 2. The use according to claim 1, characterized in that The first organic solvent is a mixture of ethyl acetate and petroleum ether in any proportion.

3. The use according to claim 2, characterized in that The volume ratio of ethoxylated column[6] aromatic hydrocarbon to organic solvent is 1:20-40.

4. The use according to claim 1, characterized in that The standing time is 12 to 36 hours.

5. A method for recovering nitroazide from waste, characterized in that: Methods include: Ethoxy [6] aromatic hydrocarbon microcrystals are added to waste and mixed at a temperature of 20 to 40°C, and the ethoxy [6] aromatic hydrocarbons adsorb nitroamine in the waste; then, a second organic solvent is used to decompose and recover the ethoxy [6] aromatic hydrocarbons and nitroamine; the preparation method of the ethoxy [6] aromatic hydrocarbon microcrystals comprises: a saturated first organic solvent solution of ethoxy [6] aromatic hydrocarbons at 40 to 50°C is filtered while hot, the filtrate is allowed to stand at room temperature, and the precipitated solid is vacuum dried to obtain ethoxy [6] aromatic hydrocarbon microcrystals; the structural formula of the ethoxy [6] aromatic hydrocarbons is: 。 6. The recycling method according to claim 5, characterized in that The second organic solvent is dichloromethane and methanol.

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