Synchronous preparation method of tetrabutylurea and phenol

Abstract

The invention relates to the technical field of organic synthesis, in particular to a synchronous preparation method of tetrabutylurea and phenol, which comprises the following preparation steps: mixing a diphenyl carbonate compound as shown in a formula (II) with di-n-butylamine, and stirring at 20-40 DEG C to obtain a mixed solution; and carrying out step-by-step reduced pressure distillation treatment on the mixed solution, and separating to obtain phenol and tetrabutyl urea as shown in the formula (I). The preparation method provided by the invention can be used for preparing high-purity tetrabutylurea, is simple, high in efficiency, non-toxic in raw materials, low in requirements on equipment, free of three wastes, green and environment-friendly, and can be used for recovering phenol at the same time, thereby achieving multiple purposes.

Description

Technical Field

[0001] The present application relates to the field of organic synthesis, and in particular to a method for synchronously preparing tetrabutyl urea and phenol. Background Art

[0002] Tetrabutylurea is an important chemical raw material and intermediate, and can also be used as a solvent, catalyst or extractant for organic chemical reactions. Currently, the chemical synthesis methods of tetrabutylurea include phosgene method, diphosgene method, triphosgene method, carbamoyl chloride method, carbon monoxide method, carbon dioxide method, dimethyl carbonate method, etc.

[0003] The phosgene method, diphosgene method or triphosgene method are relatively mature and widely used. However, the phosgene method requires the use of highly toxic raw material phosgene, which is difficult to store and transport, and produces a large amount of hydrogen chloride gas during preparation, which is highly corrosive, has strict requirements on equipment, produces a large amount of waste gas, and pollutes the environment. The diphosgene and triphosgene methods are slightly less toxic, but there are still problems of hydrogen chloride gas corrosion and environmental pollution.

[0004] The carbamoyl chloride method uses N, N-dibutylcarbamoyl chloride as raw materials to react with amine compounds to prepare the corresponding alkyl urea compounds. N, N-dibutylcarbamoyl chloride is not easy to obtain and the cost is too high.

[0005] The carbon monoxide method and the carbon dioxide method are to react CO2 or CO as carbonyl with amine compounds to prepare the corresponding alkyl urea compounds. Most carbonyl insertion reactions require the use of expensive catalysts, and some also require the use of toxic solvents such as carbon tetrachloride, which will destroy ozone when released into the environment, which is not in line with the concept of green chemistry. There is currently no example of industrial production, and the yield needs to be improved.

[0006] Patent document CN106831493A records a preparation method using dimethyl carbonate as raw material. In the presence of a strong organic base, dimethyl carbonate and di-n-butylamine react under reflux conditions to generate tetrabutyl urea. The reaction has very high requirements on the dryness of the raw materials and requires the addition of a large amount of strong base, which has high requirements on equipment. The amount of solvent added is about 4 to 5 times that of di-n-butylamine, resulting in complicated post-processing and low production efficiency.

[0007] Based on this, it is very necessary to develop a green, environmentally friendly, low-equipment-requirement and simple method for preparing tetrabutyl urea. Summary of the invention

[0008] Based on this, one or more embodiments of the present application provide a method for the simultaneous preparation of tetrabutyl urea and phenol, which has simple steps, high production efficiency, non-toxic raw materials, low equipment requirements, does not produce three wastes, and is green and environmentally friendly.

[0009] The simultaneous preparation method of tetrabutyl urea and phenol in the embodiment of the present application can produce high-purity tetrabutyl urea and can recover high-purity phenol, achieving multiple goals at one stroke and fully implementing the concept of maximizing resource utilization and green production.

[0010] The technical solution of this application includes the following contents:

[0011] A method for synchronously preparing tetrabutyl urea and phenol comprises the following steps:

[0012] The diphenyl carbonate compound represented by formula (II) and di-n-butylamine are mixed, and stirred at 20° C. to 40° C. to obtain a mixed solution;

[0013] The mixed solution is subjected to step-by-step reduced pressure distillation to separate phenol and tetrabutyl urea represented by formula (I);

[0014] ;

[0015] Wherein, each occurrence of R is independently selected from any one of H, halogen, nitro and other electron withdrawing groups.

[0016] In some embodiments, the molar ratio of the diphenyl carbonate compound to the di-n-butylamine is 1:(2-2.2).

[0017] In some embodiments, the step of mixing the diphenyl carbonate compound represented by formula (II) and di-n-butylamine and stirring at 20° C. to 40° C. to obtain a mixed solution comprises:

[0018] The diphenyl carbonate compound is added to di-n-butylamine in batches under stirring, and after stirring at 20° C. to 40° C. for 4 hours, the content of the diphenyl carbonate compound in the mixed solution is detected every 1 to 2 hours. When the content is ≤0.15%, stirring is stopped to obtain the mixed solution.

[0019] In some embodiments, the stirring time is 4 h to 20 h.

[0020] In some embodiments, the mixed solution is subjected to stepwise reduced pressure distillation to separate phenol and tetrabutyl urea represented by formula (I), comprising:

[0021] The mixed liquid is subjected to a first reduced pressure distillation treatment to obtain a first fraction and a first residue;

[0022] The first residue is subjected to a second reduced-pressure distillation treatment to obtain a second fraction, the phenol, and a second residue;

[0023] The second residue is subjected to a third reduced pressure distillation treatment to obtain a third fraction, thereby obtaining the tetrabutyl urea represented by the formula (I);

[0024] The pressure of the first vacuum distillation is -0.08MPa~-0.09MPa, and the temperature is 90℃~100℃;

[0025] The pressure of the second vacuum distillation is -0.09MPa~-0.095MPa, and the temperature is 105~135℃;

[0026] The pressure of the third reduced pressure distillation is -0.098MPa~-0.1MPa, and the temperature is 140℃~165℃.

[0027] In some embodiments, the step of recovering the first fraction is further included;

[0028] The first fraction includes the di-n-butylamine that has not reacted with the diphenyl carbonate compound.

[0029] In some embodiments, the first fraction comprises 98.5% to 99.5% by weight of di-n-butylamine.

[0030] In some embodiments, the second fraction comprises 98% to 99.5% by weight of phenol.

[0031] In some embodiments, the third fraction comprises 99.5-99.9% by weight of tetrabutyl urea.

[0032] In some embodiments, the purity of the tetrabutyl urea is ≥ 99.5%.

[0033] At present, the preparation of tetrabutylurea mostly requires the use of toxic raw materials, and a large amount of "three wastes" such as corrosive hydrogen chloride gas, waste brine, etc. are generated during the preparation process. The preparation method of the present application is green and environmentally friendly, the raw materials are recyclable, the recovery rate can reach 90-95%, and no harmful by-products are generated.

[0034] The di-n-butylamine of the present application is an organic base, which itself has a catalytic effect on the ester aminolysis reaction. At the same time, phenol is also a relatively good leaving group, especially when there is an electron-withdrawing group. Therefore, the reaction can be carried out smoothly under very mild conditions. After the reaction is completed, the system is a mixture of di-n-butylamine, phenol, and tetrabutyl urea. The boiling points of the three substances are quite different. Through a suitable distillation process, di-n-butylamine (boiling point 163°C), phenol (boiling point 182°C) and tetrabutyl urea (boiling point 379.8°C) can be separated with high purity. The di-n-butylamine separated by distillation can be recycled and reused. Phenol is an important basic chemical raw material and can be sold directly. The entire reaction process can be carried out at room temperature and pressure, with a simple process, easy post-treatment, high conversion rate, high selectivity, and efficient production. The product tetrabutyl urea has an extremely high purity (about 99.5%~99.9%). BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0036] Figure 1 This is a process flow chart for preparing tetrabutyl urea according to an embodiment of the present application. DETAILED DESCRIPTION

[0037] The present application will be further described below in conjunction with the embodiments, examples and accompanying drawings. It should be understood that these examples are only used to illustrate the present application and are not intended to limit the scope of the present application. In addition, it should be understood that after reading the content taught in the present application, those skilled in the art may make various changes or modifications to the present application, and these equivalent forms also fall within the scope of protection of the claims attached to the present application.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0039] the term

[0040] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0041] The term "and / or" used in this article includes any one of two or more related listed items, and also includes any and all combinations of related listed items, and the arbitrary and all combinations include any two related listed items, any more related listed items, or all related listed items. It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or", it should be understood that in this application, the technical solution undoubtedly includes technical solutions that are all connected by "logical and", and undoubtedly includes technical solutions that are all connected by "logical or". For example, "A and / or B" includes three parallel solutions of A, B and A+B. For example, the technical solution of "A, and / or, B, and / or, C, and / or, D" includes any one of A, B, C, and D (that is, the technical solution that is all connected by "logical OR"), and also includes any and all combinations of A, B, C, and D, that is, the combination of any two or any three of A, B, C, and D, and also includes the combination of four of A, B, C, and D (that is, the technical solution that is all connected by "logical AND").

[0042] Herein, "preferred", "preferable", "better", etc. are only used to describe implementation methods or examples with better effects. It should be understood that they do not constitute limitations on the scope of protection of this application.

[0043] In the present application, "further" and the like are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of the present application.

[0044] In this application, the terms "first", "second", etc. are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0045] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0046] In this application, when it comes to numerical intervals (i.e., numerical ranges), unless otherwise specified, the optional numerical distribution is considered continuous within the above numerical interval, and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical range, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to integers within the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints. In addition, when multiple ranges are provided to describe features or characteristics, these ranges can be combined. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all subranges included therein.

[0047] In the present application, weight may be μg, mg, g, kg or other mass units known in the chemical industry.

[0048] In the present application, compound II and the compound represented by formula (II) have the same meaning and can be used interchangeably, both referring to the general structure of Compound III and the compound represented by formula (III) have the same meaning and can be used interchangeably, both referring to the structure Compound I and the compound represented by formula (I) have the same meaning and can be used interchangeably, both referring to a compound having a structure of A compound with the chemical name N, N, N', N'-tetrabutylurea.

[0049] At present, there are many chemical preparation methods for tetrabutyl urea, including phosgene method, diphosgene method, triphosgene method, carbamoyl chloride method, dimethyl carbonate method, carbon monoxide method, carbon dioxide method, etc. However, the current preparation schemes generally have the following problems: 1. The raw materials are toxic, which not only has high transportation costs but also has production safety hazards; 2. The raw materials are highly corrosive and have high requirements for equipment; 3. The preparation process produces three wastes that pollute the environment; 4. The production efficiency is low, and it is difficult to achieve large-scale production; 5. Expensive catalysts are required, which increases production costs.

[0050] The simultaneous preparation method of tetrabutyl urea and phenol of the present application does not require the use of toxic raw materials, does not produce toxic gases or wastewater during the preparation process, and is safe and environmentally friendly. Incompletely reacted raw materials can be recycled and used with a high recovery rate. The by-products are important chemical intermediates that can be effectively recycled and utilized, which is in line with the concept of green chemical production. The process is simple, post-processing is easy, and it is suitable for large-scale industrial production.

[0051] One or more embodiments of the present application provide a method for the simultaneous preparation of tetrabutyl urea and phenol, comprising the following preparation steps: mixing a diphenyl carbonate compound represented by formula (II) and di-n-butylamine, and stirring at 20° C. to 40° C. to obtain a mixed solution;

[0052] The mixed solution is subjected to step-by-step reduced pressure distillation to separate phenol and tetrabutyl urea represented by formula (I);

[0053] ;

[0054] Wherein, each occurrence of R is independently selected from any one of H, halogen, nitro and other electron withdrawing groups.

[0055] In some embodiments, each occurrence of R is independently selected from H, or a halogen atom, or a nitro group or an electron withdrawing group.

[0056] In some embodiments, each occurrence of R is independently H.

[0057] In some embodiments, the molar ratio of diphenyl carbonate to di-n-butylamine is 1:(2-2.2). It can further be 1:(2-2.2). For example, 1:2, 1:2.1, 1:2.2, etc.

[0058] In some embodiments, the diphenyl carbonate compound represented by formula (II) and di-n-butylamine are mixed and stirred at 20°C to 40°C. For example, the stirring temperature is 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, 36°C, 37°C, 38°C, 39°C, 40°C, etc.

[0059] In some embodiments, the step of mixing the diphenyl carbonate compound represented by formula (II) and di-n-butylamine and stirring at 20° C. to 40° C. to obtain a mixed solution comprises:

[0060] Add diphenyl carbonate compounds in batches to di-n-butylamine in a stirring state, and mix them. After stirring at 20° C. to 40° C. for 4 hours, detect the content of diphenyl carbonate compounds in the mixed solution every 1 to 2 hours. When the content is ≤0.15%, stop stirring to obtain a mixed solution.

[0061] In some embodiments, the stirring time is 4 h to 20 h, and can further be 6 h to 14 h, for example 4 h, 6 h, 8 h, 10 h, 12 h, 14 h, 16 h, 18 h, 20 h, etc.

[0062] In some embodiments, the mixed solution is subjected to stepwise reduced pressure distillation to separate phenol and tetrabutyl urea represented by formula (I), comprising:

[0063] The mixed liquid is subjected to a first reduced pressure distillation treatment to obtain a first fraction and a first residue;

[0064] The first residue is subjected to a second reduced-pressure distillation to obtain a second fraction, phenol, and a second residue;

[0065] The second residue is subjected to a third reduced pressure distillation treatment to obtain a third fraction, and tetrabutyl urea represented by formula (I) is obtained;

[0066] The pressure of the first vacuum distillation is -0.08MPa~-0.09MPa, and the temperature is 90℃~100℃;

[0067] The pressure of the second vacuum distillation is -0.09MPa~-0.095MPa, and the temperature is 105~135℃;

[0068] The pressure of the third reduced pressure distillation is -0.098MPa~-0.1MPa, and the temperature is 140℃~165℃.

[0069] In some embodiments, the method for the simultaneous preparation of tetrabutylurea and phenol further comprises the step of recovering the first fraction;

[0070] The first fraction includes di-n-butylamine that has not reacted with the diphenyl carbonate compound (that is, after the diphenyl carbonate compound represented by formula (II) and di-n-butylamine are mixed, in the step of stirring at 20°C to 40°C, a portion of the di-n-butylamine does not react with the diphenyl carbonate compound and exists in the mixed liquid after the stirring).

[0071] In some embodiments, the first fraction comprises 98.5% to 99.5% by weight of di-n-butylamine.

[0072] In some embodiments, the second fraction comprises 98.0% to 99.5% by weight of phenol.

[0073] In some embodiments, the third fraction comprises 99.5-99.9% by weight of the tetrabutyl urea.

[0074] In some embodiments, the purity of tetrabutylurea is ≥ 99.5%.

[0075] The simultaneous preparation method of tetrabutyl urea and phenol in one or more embodiments of the present application can obtain high-purity tetrabutyl urea without chlorine residue and has a wider application.

[0076] In some embodiments, the purity of tetrabutyl urea is ≥99.5%, and can further be 99.5% to 99.9%, for example 99.5%, 99.6%, 99.7%, 99.85%, 99.9%, etc.

[0077] The simultaneous preparation method of tetrabutyl urea and phenol in one or more embodiments of the present application can obtain high-purity phenol.

[0078] In some embodiments, the purity of phenol is ≥98%, and may further be 98% to 99.5%, for example 98%, 98.5%, 98.9%, 99%, 99.5%, etc.

[0079] The following are some specific embodiments.

[0080] For experimental parameters not specified in the following specific embodiments, reference is made to the instructions given in the present application document, and reference may also be made to experimental manuals in the art or other experimental methods known in the art, or to experimental conditions recommended by manufacturers.

[0081] The raw materials and reagents involved in the following specific examples can be obtained from commercial sources, or can be prepared by those skilled in the art according to known methods.

[0082] Raw materials: di-n-butylamine: purity greater than 99.0%; diphenyl carbonate: purity greater than 98.5%.

[0083] The procedure of the segmented distillation in the following embodiment is as follows: the pressure of the first vacuum distillation is -0.08MPa~-0.09MPa, the temperature is 90℃~100℃, and di-n-butylamine is recovered; the pressure of the second vacuum distillation is -0.09MPa~-0.095MPa, the temperature is 105℃~135℃, and phenol is recovered; the pressure of the third vacuum distillation is -0.098MPa~-0.1MPa, the temperature is 140℃~165℃, and tetrabutylurea is recovered.

[0084] Example 1

[0085] 270.9 g (2.1 mol) of raw material di-n-butylamine was added to a three-necked flask. Under stirring, 214 g (1 mol) of diphenyl carbonate was added in batches. With the addition of diphenyl carbonate, the reaction temperature rose slowly. The reaction temperature was controlled at 20°C ~40°C. The reaction lasted for 12 h. The content of diphenyl carbonate was 0.15% after sampling. The reaction was stopped and the reaction solution was transferred to a distillation kettle. By controlling the kettle temperature and system vacuum, 12.1 g (purity 99.3%) of di-n-butylamine, 180.5 g (99.2%) of phenol and 269.8 g (content 99.7%) of tetrabutyl urea were recovered by distillation, with a yield of 95.0%. After calculation, the recovery rate of phenol was 95%; the recovery rate of di-n-butylamine was 93%.

[0086] Example 2

[0087] 516.0 g (4.0 mol) of di-n-butylamine was added to a three-necked flask, and 214 g (1.0 mol) of diphenyl carbonate was added in batches under stirring. With the addition of diphenyl carbonate, the reaction temperature slowly rose, and the reaction temperature was maintained at 20-40°C. The reaction was kept warm for 6 hours, and the sampling control showed that the diphenyl carbonate content was 0.12%. The reaction was stopped, and the reaction solution was transferred to a distillation kettle. By controlling the kettle temperature and the system vacuum, 249.1 g (purity 99.4%) of di-n-butylamine, 181.1 g (purity 99.2%) of phenol, and 271.8 g (purity 99.7%) of tetrabutyl urea were obtained by distillation, with a yield of 95.7%. After calculation, the recovery rate of phenol was 95.6%; the recovery rate of di-n-butylamine was 91%.

[0088] Example 3

[0089] 270.9 g (2.1 mol) of di-n-butylamine (recovered, purity 99.2%) was added to a three-necked flask, and 214 g (1.0 mol) of diphenyl carbonate was added in batches under stirring. With the addition of diphenyl carbonate, the reaction temperature slowly rose, and the reaction temperature was maintained at 20-40°C. The reaction was kept warm for 14 hours, and the sampling control showed that the diphenyl carbonate content was 0.20%. The reaction was stopped, and the reaction solution was transferred to a distillation kettle. By controlling the kettle temperature and the system vacuum, 12.5 g (purity 99.0%) of di-n-butylamine, 177.2 g (purity 99.1%) of phenol, and 264.8 g (purity 99.7%) of tetrabutyl urea were obtained by distillation, with a yield of 93.2%. After calculation, the recovery rate of phenol was 93%; the recovery rate of di-n-butylamine was 93.8%.

[0090] Example 4

[0091] 270.9 g (2.1 mol) of raw material di-n-butylamine was added to a three-necked flask. Under stirring, 352 g (1 mol) of bis-2,4-dichlorophenyl carbonate (CAS: 26496-99-1) was added in batches. With the addition of bis-2,4-dichlorophenyl carbonate, the reaction temperature rose slowly. The reaction temperature was controlled at 20°C ~ 40°C. The reaction lasted for 12 h. The sampling control showed that the content of bis-2,4-dichlorophenyl carbonate was 0.18%. The reaction was stopped and the reaction solution was transferred to a distillation kettle. By controlling the kettle temperature and system vacuum, 12.7 g (purity 99.3%) of di-n-butylamine, 312.6 g (99.2%) of phenol, and 269.8 g (content 99.7%) of tetrabutyl urea were recovered by distillation, with a yield of 95.0%. After calculation, the recovery rate of 2,4-dichlorophenol was 95%; the recovery rate of di-n-butylamine was 96.8%.

[0092] Comparative Example 1

[0093] 2.14 g of sodium methoxide and 97 g of dimethyl carbonate were dissolved in 150 g of methanol, and the temperature was raised to 30°C to obtain a mixed solution. 42.4 g of di-n-butylamine was added dropwise to the mixed solution at 50°C to 60°C, and the temperature was raised to reflux after the addition was complete. The mixture was kept warm for 5 hours to obtain a reaction solution. The reaction solution was analyzed by mass spectrometry, and the obtained reaction solution contained only N, N-dibutyl methyl carbamate, indicating that tetrabutyl urea could not be prepared after replacing diphenyl carbonate with dimethyl carbonate.

[0094] Comparative Example 2

[0095] 270.9 g (2.1 mol) of raw material di-n-butylamine was added to a three-necked flask, and 90.07 g (1 mol) of dimethyl carbonate was added dropwise under stirring. The reaction temperature remained basically unchanged and was controlled at 20°C ~ 25°C. The reaction was carried out for 20 h. Sampling was performed for mid-control and mass spectrometry analysis. Only N, N-dibutyl methyl carbamate was obtained, and no tetrabutyl urea was generated. This indicates that under the process conditions of the present application, tetrabutyl urea cannot be prepared after replacing diphenyl carbonate with dimethyl carbonate.

[0096] Comparative Example 3

[0097] 270.9 g (2.1 mol) of raw material di-n-butylamine was added to a three-necked flask, and 214 g (1 mol) of diphenyl carbonate was added in batches under stirring. With the addition of diphenyl carbonate, the reaction temperature rose slowly, and the reaction temperature was controlled at 20°C ~40°C. The reaction was continued for 12 h. The content of diphenyl carbonate was 0.15% after sampling. The reaction was stopped and the reaction solution was transferred to a distillation kettle. 12.7 g of di-n-butylamine (purity 95.3%), 192.1 g of phenol (94.2%) and 269.8 g of tetrabutyl urea (content 99.2%) were recovered by distillation in sequence under a vacuum of -0.098~-0.01Mpa and only by controlling the kettle temperature. The recovered di-n-butylamine and phenol contents were unqualified, and the obtained tetrabutyl urea content did not reach 99.5%.

[0098] All documents mentioned in this application are cited as references in this application, just as each document is cited as reference separately. Unless they conflict with the application purpose and / or technical solution of this application, the cited documents involved in this application are cited with all contents and all purposes. When the cited documents are involved in this application, the definitions of relevant technical features, terms, nouns, phrases, etc. in the cited documents are also cited. When the cited documents are involved in this application, the examples and preferred methods of the cited relevant technical features can also be incorporated into this application as references, but are limited to the implementation of this application. It should be understood that when the cited content conflicts with the description in this application, the present application shall prevail or be modified adaptively according to the description of this application.

[0099] The technical features of the above-mentioned implementation modes and examples can be combined in any appropriate manner. To make the description concise, not all possible combinations of the technical features in the above-mentioned implementation modes and examples are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0100] The above-described embodiments only express several implementation methods of the present application, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for those of ordinary skill in the art, without departing from the concept of the present application, several variations and improvements can also be made, which all belong to the protection scope of the present application. In addition, it should be understood that after reading the above-mentioned teaching content of the present application, those skilled in the art can make various changes or modifications to the present application, and the equivalent forms obtained also fall within the protection scope of the present application. It should also be understood that the technical solutions obtained by those skilled in the art on the basis of the technical solutions provided in the present application through logical analysis, reasoning or limited experiments are all within the protection scope of the claims attached to the present application. Therefore, the protection scope of the patent of the present application shall be based on the attached claims, and the description and drawings may be used to explain the contents of the claims.

Claims

1. A method for the simultaneous preparation of tetrabutyl urea and phenol, characterized in that: The steps include: The diphenyl carbonate compound represented by formula (II) and di-n-butylamine are mixed, and stirred at 20° C. to 40° C. to obtain a mixed solution; The mixed solution is subjected to step-by-step reduced pressure distillation to separate phenol and tetrabutyl urea represented by formula (I); ； Wherein, each occurrence of R is independently selected from any one of H, halogen, nitro and other electron withdrawing groups.

2. The method for the simultaneous preparation of tetrabutyl urea and phenol according to claim 1, characterized in that: The molar ratio of the diphenyl carbonate compound to the di-n-butylamine is 1:(2-2.2).

3. The method for the simultaneous preparation of tetrabutyl urea and phenol according to claim 1, characterized in that: The step of mixing the diphenyl carbonate compound represented by formula (II) and di-n-butylamine and stirring at 20° C. to 40° C. to obtain a mixed solution comprises: The diphenyl carbonate compound is added to di-n-butylamine in batches under stirring, and after stirring at 20° C. to 40° C. for 4 hours, the content of the diphenyl carbonate compound in the mixed solution is detected every 1 to 2 hours. When the content is ≤0.15%, stirring is stopped to obtain the mixed solution.

4. The method for the simultaneous preparation of tetrabutyl urea and phenol according to claim 3, characterized in that: The stirring time is 4 h to 20 h.

5. The method for the simultaneous preparation of tetrabutyl urea and phenol according to claim 1, characterized in that: The mixed solution is subjected to stepwise reduced pressure distillation to separate phenol and tetrabutyl urea represented by formula (I), comprising: The mixed liquid is subjected to a first reduced pressure distillation treatment to obtain a first fraction and a first residue; The first residue is subjected to a second reduced-pressure distillation treatment to obtain a second fraction, the phenol, and a second residue; The second residue is subjected to a third reduced pressure distillation treatment to obtain a third fraction, thereby obtaining the tetrabutyl urea represented by the formula (I); The pressure of the first vacuum distillation is -0.08MPa~-0.09MPa, and the temperature is 90℃~100℃; The pressure of the second vacuum distillation is -0.09MPa~-0.095MPa, and the temperature is 105~135℃; The pressure of the third reduced pressure distillation is -0.098MPa~-0.1MPa, and the temperature is 140℃~165℃.

6. The method for the simultaneous preparation of tetrabutyl urea and phenol according to claim 5, characterized in that: Also includes the step of recovering the first fraction; The first fraction includes the di-n-butylamine that has not reacted with the diphenyl carbonate compound.

7. The method for the simultaneous preparation of tetrabutyl urea and phenol according to claim 6, characterized in that: The first fraction comprises 98.5% to 99.5% by weight of di-n-butylamine.

8. The method for the simultaneous preparation of tetrabutyl urea and phenol according to claim 5, characterized in that: The second fraction comprises 98% to 99.5% by weight of phenol.

9. The method for the simultaneous preparation of tetrabutyl urea and phenol according to claim 5, characterized in that: The third fraction comprises 99.5-99.9% by weight of tetrabutyl urea.

10. The method for the simultaneous preparation of tetrabutyl urea and phenol according to any one of claims 1 to 9, characterized in that: The purity of the tetrabutyl urea is ≥99.5%.

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