Preparation and purification method of tetrabutyl urea

Abstract

The invention relates to a preparation and purification method of tetrabutyl urea, and relates to the technical field of organic synthesis. According to the method, a toluene solution of bis (trichloromethyl) carbonate, di-n-butylamine and a sodium hydroxide solution are used as main raw materials, dodecyl dimethyl betaine is used as a phase transfer catalyst to prepare tetrabutylurea, benzoyl peroxide is added into a crude product of tetrabutylurea, and then vacuum rectification is performed to obtain the tetrabutylurea. A rectification product is further adsorbed by a copper ion loaded modified halloysite nanotube material, and then a tetrabutyl urea product is prepared. The copper ion loaded modified halloysite nanotube material is prepared by the following steps: calcining industrial-grade halloysite powder at a high temperature, cooling, adding water and copper chloride dihydrate, stirring, standing, aging, centrifugally separating, washing with deionized water, and drying in vacuum, thereby obtaining the copper ion loaded modified halloysite nanotube material. The method has the characteristics of high reaction yield, low content of impurities such as di-n-butylamine, chlorine and sulfide in the product, and easiness in industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of organic synthesis, in particular to a preparation method of tetrabutyl urea and a purification method thereof. Background Art

[0002] Tetrabutylurea is a widely used organic synthesis intermediate and can also be used as a solvent, extractant, and catalyst in organic chemistry. It is particularly useful as a solvent in hydrogen peroxide production, replacing trioctyl phosphate. Because the solubility of hydrogenated anthraquinone in tetrabutylurea is greater than that in trioctyl phosphate, it improves hydrogenation efficiency in hydrogen peroxide production and increases the distribution coefficient during extraction, thereby increasing production capacity, raising hydrogen peroxide concentration, and reducing production energy consumption.

[0003] The traditional production process of tetrabutyl urea mainly adopts the reaction of phosgene or diphosgene with di-n-butylamine. Zhou Shigang et al. (Yunnan Chemical Industry, 2023, 6(50):117-120) reported a method for synthesizing tetrabutyl urea using phosgene and di-n-butylamine as raw materials. Yan Chuanming (Jiangsu Pesticides, 1997, 19(3):4-5) reported a method for synthesizing tetrabutyl urea using diphosgene and di-n-butylamine as raw materials. Both phosgene and diphosgene are highly toxic. Phosgene is a gas and diphosgene is a liquid, but it is extremely volatile. The production and storage processes have high safety risks and environmental pollution risks.

[0004] Bis(trichloromethyl)carbonate, abbreviated as BTC, commonly known as triphosgene, also known as solid phosgene, has a boiling point of 203-206°C (partial decomposition). Triphosgene has high stability and low volatility and can be treated as a general toxic chemical. It is a widely used green alternative to phosgene and is safer than phosgene in terms of use, transportation, and storage.

[0005] Replacing phosgene and diphosgene with bis(trichloromethyl) carbonate and reacting it with di-n-butylamine to produce tetrabutyl urea can greatly reduce safety and environmental risks. It has the advantages of mild process conditions, easy control, high reaction product yield and purity, and low cost.

[0006] CN02112082.X reports a method for preparing the organic compound tetrabutylurea, which is synthesized using dibutylamine and bis(trichloromethyl) carbonate as raw materials in an organic solvent. Nitrogen is passed through the reaction process to drive out the by-product hydrogen chloride. The process is relatively complex and it is difficult to completely remove the hydrogen chloride in the system.

[0007] The chemical reaction formula for synthesizing tetrabutyl urea using bis(trichloromethyl) carbonate and di-n-butylamine as raw materials is:

[0008]

[0009] Currently, the purification process for tetrabutylurea products generally uses a combination of water washing and distillation, but satisfactory purification results are difficult to achieve. Typical domestic tetrabutylurea products contain 0.1% di-n-butylamine, 10 ppm total chlorine, and 5 ppm total sulfur. These high levels of di-n-butylamine, total chlorine, and total sulfur can seriously affect the product's performance. For example, when used as a solvent in hydrogen peroxide production, replacing trioctyl phosphate, the presence of di-n-butylamine, chlorine, and sulfide impurities can affect the hydrogenation efficiency of alkyl anthraquinones in the synthetic working fluid, the concentration of hydrogen peroxide, and the partition coefficient of hydrogen peroxide between the working fluid and the aqueous phase, thereby impacting the stability and efficiency of the production process. Summary of the Invention

[0010] The main purpose of the present invention is to provide a preparation method of tetrabutyl urea and a purification method thereof, so as to overcome the deficiencies in the prior art.

[0011] In order to solve the above problems, the present invention provides a method for preparing tetrabutyl urea and purifying the same, and the steps are as follows:

[0012] S1: Add 1-3 parts of bis(trichloromethyl)carbonate and 2.85-8.55 parts of toluene to a preparation kettle according to their mass ratios, and stir until completely dissolved;

[0013] S2: Add 2.65-8.0 parts of di-n-butylamine, 8.4-12.8 parts of 10-20% by mass sodium hydroxide solution, and 0.005-0.02 parts of dodecyl dimethyl betaine to a reaction kettle, cool to 0-5°C while stirring, and slowly add dropwise the bis(trichloromethyl) carbonate toluene solution prepared in S1 to carry out the reaction;

[0014] S3: After the reaction is completed, the layers are allowed to stand and the organic phase and the aqueous phase are separated. The organic phase is distilled to recover toluene, cooled to room temperature, first washed with a 5-10% by mass hydrochloric acid solution to a pH of 1-2, then washed with a 2-5% by mass sodium hydroxide solution to a pH of 8-10, and the organic phase is separated to obtain a crude tetrabutylurea product;

[0015] S4: adding 0.002-0.006 parts of benzoyl peroxide, stirring for 30-60 minutes and then performing vacuum distillation;

[0016] S5: The tetrabutyl urea obtained by distillation flows through an adsorption column filled with copper ion loaded modified halloysite nanotube material to obtain a tetrabutyl urea product.

[0017] As a preferred embodiment of the present invention, the reaction temperature of S2 is 30-35° C., and the reaction time is 2-4 hours.

[0018] As a preferred embodiment of the present invention, the preparation method of the copper ion loaded modified halloysite nanotube material is:

[0019] According to the weight ratio, 1-3 parts of industrial-grade halloysite powder with a purity of 98% are calcined at high temperature. After cooling, 30-100 parts of water and 0.3-1.0 parts of copper chloride dihydrate are added, and the mixture is stirred for 2-3 hours, allowed to stand for aging, centrifuged, washed with deionized water 3-4 times, and vacuum-dried at 50-60°C to prepare a copper ion-loaded modified halloysite nanotube material.

[0020] As a preferred embodiment of the present invention, the high-temperature calcination temperature is 300-500° C. and the time is 2-4 hours.

[0021] As a preferred embodiment of the present invention, the static aging time is 12-24 hours.

[0022] Technical effects:

[0023] The preparation and purification method of tetrabutyl urea of ​​the present invention has the following significant effects compared with the prior art:

[0024] The present invention provides a preparation method and purification method of tetrabutyl urea. The tetrabutyl urea is prepared using a toluene solution of bis(trichloromethyl) carbonate and di-n-butylamine as main raw materials and a 20% by mass sodium hydroxide solution as an acid-binding agent. Since the reaction is a mixed system of an organic phase and an aqueous phase, dodecyl dimethyl betaine is added as a phase transfer catalyst to effectively promote the reaction, make the reaction milder, and reduce the generation of side reactions.

[0025] In order to improve product quality, the present invention adds benzoyl peroxide to a crude tetrabutylurea product, stirs and mixes the mixture, and then performs vacuum distillation to reduce the residual dibutylamine. The distillation product is further passed through an adsorption column containing a copper ion-loaded modified halloysite nanotube material to obtain a tetrabutylurea product. The halloysite nanotube is a natural clay mineral with a hollow tubular structure, an outer diameter of 20-200 nm, an inner diameter of 10-100 nm, and a length of several microns. After being modified by copper ion loading, it has the characteristics of a hollow tubular structure and a high specific surface area, providing a large number of adsorption sites, and can physically capture the residual dibutylamine and sulfur / chlorine impurities in the tetrabutylurea through van der Waals forces or hydrogen bonds. The loaded copper (such as Cu 0 、Cu 2+ ) will chemically bond with sulfur-containing / chlorine-containing compounds. Through the synergistic effect of physical adsorption and chemical adsorption, the tetrabutyl urea product prepared by the present invention has low contents of di-n-butylamine, total chlorine and total sulfur, thereby achieving the purpose of purifying the product. DETAILED DESCRIPTION

[0026] In view of the deficiencies in the prior art, the inventors of this case have proposed the technical solution of the present invention after long-term research and extensive practice. The technical solution, its implementation process and principles will be further explained below.

[0027] The tetrabutyl urea prepared in the examples and comparative examples was tested using the same method as follows:

[0028] The content of tetrabutylurea and di-n-butylamine was determined by gas chromatography, chromatographic column: Agilent HP-50+, column temperature: 210°C, injection port temperature: 270°C.

[0029] The determination of total chlorine and total sulfur was carried out using a high-sensitivity X-ray fluorescence spectrometer.

[0030] The yield of the product is calculated based on bis(trichloromethyl)carbonate.

[0031] The ppm in the patent is the mass concentration.

[0032] Example 1

[0033] A method for preparing and purifying tetrabutyl urea, comprising the following steps:

[0034] S1: Add 1 kg of bis(trichloromethyl) carbonate and 2.85 kg of toluene to a preparation kettle and stir until completely dissolved;

[0035] S2: Add 2.65 kg of di-n-butylamine, 8.4 kg of 10% by mass sodium hydroxide solution, and 0.005 kg of dodecyl dimethyl betaine to the reactor, cool to 0°C with stirring, and slowly add dropwise the bis(trichloromethyl) carbonate toluene solution prepared in S1 to carry out the reaction;

[0036] S3: After the reaction is completed, the mixture is allowed to stand and the layers are separated, and the organic phase and the aqueous phase are separated. The organic phase is distilled to recover toluene, cooled to room temperature, and first washed with a 5% by mass hydrochloric acid solution to a pH of 1, and then washed with a 2% by mass sodium hydroxide solution to a pH of 8. The organic phase is separated to obtain a crude tetrabutylurea product;

[0037] S4: Add 0.002 kg of benzoyl peroxide, stir for 30 minutes and then perform vacuum distillation;

[0038] S5: The tetrabutyl urea obtained by distillation flows through an adsorption column filled with copper ion loaded modified halloysite nanotube material to obtain a tetrabutyl urea product.

[0039] The reaction temperature of S2 is 30° C. and the reaction time is 2 hours.

[0040] The preparation method of the copper ion loaded modified halloysite nanotube material is as follows:

[0041] 1 kg of industrial-grade halloysite powder with a purity of 98% was calcined at high temperature. After cooling, 30 kg of water and 0.3 kg of copper chloride dihydrate were added, stirred for 2 hours, allowed to stand for aging, centrifuged, washed three times with deionized water, and vacuum-dried at 50°C to obtain copper ion-loaded modified halloysite nanotube material.

[0042] The high-temperature calcination temperature is 300° C. and the time is 2 hours.

[0043] The standing aging time is 12 hours.

[0044] Example 2

[0045] A method for preparing and purifying tetrabutyl urea, comprising the following steps:

[0046] S1: Add 2 kg of bis(trichloromethyl) carbonate and 5 kg of toluene to a preparation kettle and stir until completely dissolved;

[0047] S2: Add 5.35 kg of di-n-butylamine, 11.5 kg of 15% by mass sodium hydroxide solution, and 0.01 kg of dodecyl dimethyl betaine to the reactor, cool to 0°C under stirring, and slowly add the bis(trichloromethyl) carbonate toluene solution prepared in S1 dropwise to carry out the reaction;

[0048] S3: After the reaction is completed, the mixture is allowed to stand and the layers are separated, and the organic phase and the aqueous phase are separated. The organic phase is distilled to recover toluene, cooled to room temperature, and first washed with a 6% by mass hydrochloric acid solution to a pH of 1, and then washed with a 3% by mass sodium hydroxide solution to a pH of 9. The organic phase is separated to obtain a crude tetrabutylurea product;

[0049] S4: Add 0.003 kg of benzoyl peroxide, stir for 40 minutes and then perform vacuum distillation;

[0050] S5: The tetrabutyl urea obtained by distillation flows through an adsorption column filled with copper ion loaded modified halloysite nanotube material to obtain a tetrabutyl urea product.

[0051] The reaction temperature of S2 is 30° C. and the reaction time is 3 hours.

[0052] The preparation method of the copper ion loaded modified halloysite nanotube material is as follows:

[0053] 2 kg of industrial-grade halloysite powder with a purity of 98% was calcined at high temperature. After cooling, 50 kg of water and 0.5 kg of copper chloride dihydrate were added, stirred for 2.5 hours, allowed to stand for aging, centrifuged, washed three times with deionized water, and vacuum-dried at 55°C to obtain copper ion-loaded modified halloysite nanotube material.

[0054] The high temperature calcination temperature is 350° C. and the time is 3 hours.

[0055] The standing aging time is 16 hours.

[0056] Example 3

[0057] A method for preparing and purifying tetrabutyl urea, comprising the following steps:

[0058] S1: Add 2 kg of bis(trichloromethyl) carbonate and 6 kg of toluene into a preparation kettle and stir until completely dissolved;

[0059] S2: Add 6 kg of di-n-butylamine, 12 kg of 15% by mass sodium hydroxide solution, and 0.015 kg of dodecyl dimethyl betaine to the reactor, cool to 5° C. under stirring, and slowly add dropwise the bis(trichloromethyl) carbonate toluene solution prepared in S1 to carry out the reaction;

[0060] S3: After the reaction is completed, the mixture is allowed to stand and the layers are separated, and the organic phase and the aqueous phase are separated. The organic phase is distilled to recover toluene, cooled to room temperature, and first washed with an 8% by mass hydrochloric acid solution to a pH of 2, and then washed with a 4% by mass sodium hydroxide solution to a pH of 9. The organic phase is separated to obtain a crude tetrabutylurea product;

[0061] S4: Add 0.005 kg of benzoyl peroxide, stir for 50 min and then perform vacuum distillation;

[0062] S5: The tetrabutyl urea obtained by distillation flows through an adsorption column filled with copper ion loaded modified halloysite nanotube material to obtain a tetrabutyl urea product.

[0063] The reaction temperature of S2 is 35° C. and the reaction time is 3 hours.

[0064] The preparation method of the copper ion loaded modified halloysite nanotube material is as follows:

[0065] 2 kg of industrial-grade halloysite powder with a purity of 98% was calcined at high temperature. After cooling, 80 kg of water and 0.8 kg of copper chloride dihydrate were added, stirred for 2.5 hours, allowed to stand for aging, centrifuged, washed four times with deionized water, and vacuum-dried at 55°C to obtain copper ion-loaded modified halloysite nanotube material.

[0066] The high temperature calcination temperature is 450° C. and the time is 3 hours.

[0067] The standing aging time is 20 hours.

[0068] Example 4

[0069] A method for preparing and purifying tetrabutyl urea, comprising the following steps:

[0070] S1: Add 3 kg of bis(trichloromethyl) carbonate and 8.55 kg of toluene to a preparation kettle and stir until completely dissolved;

[0071] S2: Add 8.0 kg of di-n-butylamine, 12.8 kg of 20% by mass sodium hydroxide solution, and 0.02 kg of dodecyl dimethyl betaine to the reactor, cool to 5° C. under stirring, and slowly add dropwise the bis(trichloromethyl) carbonate toluene solution prepared in S1 to carry out the reaction;

[0072] S3: After the reaction is completed, the mixture is allowed to stand and the layers are separated, and the organic phase and the aqueous phase are separated. The organic phase is distilled to recover toluene, cooled to room temperature, and first washed with a 10% by mass hydrochloric acid solution to a pH of 2, and then washed with a 5% by mass sodium hydroxide solution to a pH of 10, and the organic phase is separated to obtain a crude tetrabutylurea product;

[0073] S4: Add 0.006 kg of benzoyl peroxide, stir for 60 min and then perform vacuum distillation;

[0074] S5: The tetrabutyl urea obtained by distillation flows through an adsorption column filled with copper ion loaded modified halloysite nanotube material to obtain a tetrabutyl urea product.

[0075] The reaction temperature of S2 is 35° C. and the reaction time is 4 hours.

[0076] The preparation method of the copper ion loaded modified halloysite nanotube material is as follows:

[0077] 3 kg of industrial-grade halloysite powder with a purity of 98% was calcined at high temperature. After cooling, 100 kg of water and 1.0 kg of copper chloride dihydrate were added, stirred for 3 hours, allowed to stand for aging, centrifuged, washed four times with deionized water, and vacuum-dried at 60°C to obtain copper ion-loaded modified halloysite nanotube material.

[0078] The high temperature calcination temperature is 500° C. and the time is 4 hours.

[0079] The standing aging time is 24 hours.

[0080] Comparative Example 1

[0081] A method for preparing and purifying tetrabutyl urea, comprising the following steps:

[0082] S1: Add 1 kg of bis(trichloromethyl) carbonate and 2.85 kg of toluene to a preparation kettle and stir until completely dissolved;

[0083] S2: Add 2.65 kg of di-n-butylamine and 8.4 kg of 10% by mass sodium hydroxide solution to the reaction kettle, cool to 0°C under stirring, and slowly add the bis(trichloromethyl) carbonate toluene solution prepared in S1 dropwise to carry out the reaction;

[0084] S3: After the reaction is completed, the mixture is allowed to stand and the layers are separated, and the organic phase and the aqueous phase are separated. The organic phase is distilled to recover toluene, cooled to room temperature, and first washed with a 5% by mass hydrochloric acid solution to a pH of 1, and then washed with a 2% by mass sodium hydroxide solution to a pH of 8. The organic phase is separated to obtain a crude tetrabutylurea product;

[0085] S4: Add 0.002 kg of benzoyl peroxide, stir for 30 minutes and then perform vacuum distillation;

[0086] S5: The tetrabutyl urea obtained by distillation flows through an adsorption column filled with copper ion loaded modified halloysite nanotube material to obtain a tetrabutyl urea product.

[0087] The reaction temperature of S2 is 30° C. and the reaction time is 2 hours.

[0088] The preparation method of the copper ion loaded modified halloysite nanotube material is as follows:

[0089] 1 kg of industrial-grade halloysite powder with a purity of 98% was calcined at high temperature. After cooling, 30 kg of water and 0.3 kg of copper chloride dihydrate were added, stirred for 2 hours, allowed to stand for aging, centrifuged, washed three times with deionized water, and vacuum-dried at 50°C to obtain copper ion-loaded modified halloysite nanotube material.

[0090] The high-temperature calcination temperature is 300° C. and the time is 2 hours.

[0091] The standing aging time is 12 hours.

[0092] Comparative Example 2

[0093] A method for preparing and purifying tetrabutyl urea, comprising the following steps:

[0094] S1: Add 1 kg of bis(trichloromethyl) carbonate and 2.85 kg of toluene to a preparation kettle and stir until completely dissolved;

[0095] S2: Add 2.65 kg of di-n-butylamine, 8.4 kg of 10% by mass sodium hydroxide solution, and 0.005 kg of dodecyl dimethyl betaine to the reactor, cool to 0°C with stirring, and slowly add dropwise the bis(trichloromethyl) carbonate toluene solution prepared in S1 to carry out the reaction;

[0096] S3: After the reaction is completed, the mixture is allowed to stand and the layers are separated, and the organic phase and the aqueous phase are separated. The organic phase is distilled to recover toluene, cooled to room temperature, and first washed with a 5% by mass hydrochloric acid solution to a pH of 1, and then washed with a 2% by mass sodium hydroxide solution to a pH of 8. The organic phase is separated to obtain a crude tetrabutylurea product;

[0097] S4: vacuum distillation;

[0098] S5: The tetrabutyl urea obtained by distillation flows through an adsorption column filled with copper ion loaded modified halloysite nanotube material to obtain a tetrabutyl urea product.

[0099] The reaction temperature of S2 is 30° C. and the reaction time is 2 hours.

[0100] The preparation method of the copper ion loaded modified halloysite nanotube material is as follows:

[0101] 1 kg of industrial-grade halloysite powder with a purity of 98% was calcined at high temperature. After cooling, 30 kg of water and 0.3 kg of copper chloride dihydrate were added, stirred for 2 hours, allowed to stand for aging, centrifuged, washed three times with deionized water, and vacuum-dried at 50°C to obtain copper ion-loaded modified halloysite nanotube material.

[0102] The high-temperature calcination temperature is 300° C. and the time is 2 hours.

[0103] The standing aging time is 12 hours.

[0104] Comparative Example 3

[0105] A method for preparing and purifying tetrabutyl urea, comprising the following steps:

[0106] S1: Add 1 kg of bis(trichloromethyl) carbonate and 2.85 kg of toluene to a preparation kettle and stir until completely dissolved;

[0107] S2: Add 2.65 kg of di-n-butylamine, 8.4 kg of 10% by mass sodium hydroxide solution, and 0.005 kg of dodecyl dimethyl betaine to the reactor, cool to 0°C with stirring, and slowly add dropwise the bis(trichloromethyl) carbonate toluene solution prepared in S1 to carry out the reaction;

[0108] S3: After the reaction is completed, the mixture is allowed to stand and the layers are separated, and the organic phase and the aqueous phase are separated. The organic phase is distilled to recover toluene, cooled to room temperature, and first washed with a 5% by mass hydrochloric acid solution to a pH of 1, and then washed with a 2% by mass sodium hydroxide solution to a pH of 8. The organic phase is separated to obtain a crude tetrabutylurea product;

[0109] S4: Add 0.002 kg of benzoyl peroxide, stir for 30 minutes, and then perform vacuum distillation to obtain tetrabutyl urea product.

[0110] The reaction temperature of S2 is 30° C. and the reaction time is 2 hours.

[0111] The preparation method of the copper ion loaded modified halloysite nanotube material is as follows:

[0112] 1 kg of industrial-grade halloysite powder with a purity of 98% was calcined at high temperature. After cooling, 30 kg of water and 0.3 kg of copper chloride dihydrate were added, stirred for 2 hours, allowed to stand for aging, centrifuged, washed three times with deionized water, and vacuum-dried at 50°C to obtain copper ion-loaded modified halloysite nanotube material.

[0113] The high-temperature calcination temperature is 300° C. and the time is 2 hours.

[0114] The standing aging time is 12 hours.

[0115]

[0116]

[0117] Through the data analysis of the above examples and comparative examples, the tetrabutylurea product prepared by the present invention has high purity and yield, and the content of di-n-butylamine, total chlorine and total sulfur therein is low, thereby achieving the purpose of purifying the product.

[0118] It should be understood that the above embodiments are merely illustrative of the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent variations or modifications made in accordance with the spirit and substance of the present invention are intended to be encompassed within the scope of protection of the present invention.

Claims

1. A method for preparing tetrabutyl urea and purifying the same, comprising the following steps: S1: Add 1-3 parts of bis(trichloromethyl)carbonate and 2.85-8.55 parts of toluene to a preparation kettle according to their mass ratios, and stir until completely dissolved; S2: Add 2.65-8.0 parts of di-n-butylamine, 8.4-12.8 parts of 10-20% by mass sodium hydroxide solution, and 0.005-0.02 parts of dodecyl dimethyl betaine to a reaction kettle, cool to 0-5°C while stirring, and slowly add dropwise the bis(trichloromethyl) carbonate toluene solution prepared in S1 to carry out the reaction; S3: After the reaction is completed, the layers are allowed to stand and the organic phase and the aqueous phase are separated. The organic phase is distilled to recover toluene, cooled to room temperature, first washed with a 5-10% by mass hydrochloric acid solution to a pH of 1-2, then washed with a 2-5% by mass sodium hydroxide solution to a pH of 8-10, and the organic phase is separated to obtain a crude tetrabutylurea product; S4: adding 0.002-0.006 parts of benzoyl peroxide, stirring for 30-60 minutes and then performing vacuum distillation; S5: The tetrabutyl urea obtained by distillation flows through an adsorption column containing copper ion-loaded modified halloysite nanotube material to obtain a tetrabutyl urea product; The copper ion loaded modified halloysite nanotube material is prepared by reacting industrial-grade halloysite powder, water and copper chloride dihydrate.

2. The method for preparing and purifying tetrabutyl urea according to claim 1, wherein: The reaction temperature of S2 is 30-35°C, and the reaction time is 2-4 hours.

3. The method for preparing and purifying tetrabutyl urea according to claim 1, wherein: The preparation method of the copper ion loaded modified halloysite nanotube material is as follows: According to the weight ratio, 1-3 parts of industrial-grade halloysite powder with a purity of 98% are calcined at high temperature. After cooling, 30-100 parts of water and 0.3-1.0 parts of copper chloride dihydrate are added, and the mixture is stirred for 2-3 hours, allowed to stand for aging, centrifuged, washed with deionized water 3-4 times, and vacuum-dried at 50-60°C to prepare a copper ion-loaded modified halloysite nanotube material.

4. The method for preparing and purifying tetrabutyl urea according to claim 3, wherein: The high temperature calcination temperature is 300-500° C. and the time is 2-4 hours.

5. The method for preparing and purifying tetrabutyl urea according to claim 3, wherein: The standing aging time is 12-24 hours.

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