Method for preparing aliphatic diisocyanate by non-phosgene method
The preparation of aliphatic diisocyanates by a non-phosgene method utilizes the reaction of aliphatic diamines with carbonate diesters to generate aliphatic dicarboxylate, followed by pyrolysis. This solves the environmental pollution and equipment corrosion problems associated with the phosgene method, enabling high-purity, low-cost industrial production.
Patent Information
- Application Number
- CN202511529794.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-24
- Publication Date
- 2026-01-06
AI Technical Summary
Existing phosgene methods for preparing isocyanates suffer from high equipment costs, severe environmental pollution, impact on product quality, and industrialization challenges. Non-phosgene methods, on the other hand, face problems such as the use of precious metal catalysts and difficulty in controlling the products, making it difficult to achieve large-scale industrial production.
A non-phosgene method is adopted, in which aliphatic dicarboxylate is generated by reacting aliphatic diamine with carbonate diesters, and then aliphatic diisocyanate is prepared by thermal cracking. Non-precious metal catalysts are used to avoid the use of phosgene, reduce the emission of waste gas, wastewater, and solid waste, and improve the atom utilization rate.
The green synthesis of high-purity aliphatic diisocyanates has been achieved, avoiding the use of phosgene and the generation of corrosive gases, making it suitable for large-scale industrial applications and reducing equipment corrosion and waste gas treatment pressure.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of organic synthesis, and in particular to a method for preparing aliphatic diisocyanates without phosgene. Background Technology
[0002] Isocyanates are important organic intermediates with the chemical formula RN=C=O. They are named for the presence of the -N=C=O functional group in their molecules. Isocyanates can be classified into monoisocyanates, diisocyanates, and polyisocyanates. Among them, diisocyanates are used most extensively in the polyurethane industry. Various polyurethane materials produced from different diisocyanate raw materials such as TDI, MDI, and HMDI are widely used in the industrial production of automotive parts, shoe soles, artificial leather, coatings, adhesives, thermal insulation materials, durable polyurethane, paints, dyes, and more.
[0003] The main methods for synthesizing isocyanates include the phosgene method, the triphosgene method, the thermal decomposition method of carbamates, the reductive carbonylation method of nitro compounds, and the oxidative carbonylation method of amino compounds. Among these, the phosgene method has a high yield and has been industrialized, making it the main method for isocyanate production both domestically and internationally. However, the phosgene method for isocyanate production involves a long process route, high equipment costs, high phosgene toxicity leading to severe environmental pollution, high chlorine content in the product affecting product quality, and the emitted HCl gas being highly corrosive. How to achieve green, non-phosgene-based isocyanate production has long been a serious challenge and problem.
[0004] Compared to the phosgene process, non-phosgene methods are more environmentally friendly, meeting the standards of green chemistry and the requirements of sustainable development, and are gradually replacing phosgene as the benchmark for industrial isocyanate synthesis. The triphosgene process offers precise stoichiometry, mild reaction conditions, and simple and safe operation; however, it is expensive, and the product may contain hydrolyzed chlorine, generating hydrochloric acid that corrodes equipment. The direct carbon monoxide method, the nitro compound reduction carbonylation method, and the amino compound oxidative carbonylation method are all good methods for non-phosgene isocyanate preparation. These methods have widely available raw materials, well-defined routes, and high selectivity and conversion rates; however, they still face many challenges, including complex mechanisms, difficulty in product control, difficulties in synthesizing structurally complex isocyanates, the use of precious metal catalysts, and low CO utilization. Therefore, these non-phosgene methods for preparing diisocyanates are difficult to implement on a large industrial scale. Summary of the Invention
[0005] In view of this, the present invention provides a non-phosgene method for preparing aliphatic diisocyanates. The method of the present invention can convert aliphatic diamines to aliphatic diisocyanates without the use of phosgene. Moreover, the preparation process is simple, requires no precious metal catalysts, has high atom utilization, and the product is free of chlorine residues and has high purity, which is beneficial for large-scale industrial application.
[0006] This invention provides a method for preparing aliphatic diisocyanates without phosgene, comprising the following steps:
[0007] S1. The aliphatic diamine shown in formula A reacts with the carbonate diester compound shown in formula B to form the aliphatic dicarbamate compound shown in formula C.
[0008] S2. The aliphatic dicarboxylate compound of formula C obtained in step S1 is subjected to thermal decomposition reaction to obtain the aliphatic diisocyanate of formula I.
[0009] Formula A; Formula B;
[0010] Formula C;
[0011] Formula I;
[0012] in:
[0013] R is -(CH2) n -;
[0014] R1 is an alkane group or an aromatic group.
[0015] Preferably, in step S1, the aliphatic diamine represented by formula A is selected from at least one of ethylenediamine, propylenediamine, butanediamine, pentanediamine, hexanediamine, heptanediamine, octanediamine, nonanediamine, decanediamine, and dodecyldiamine.
[0016] Preferably, in step S1, the carbonate diester compound represented by formula B is selected from at least one of dimethyl carbonate, diethyl carbonate, dibutyl carbonate, dihexyl carbonate, and diphenyl carbonate.
[0017] Preferably, in step S1, the reaction is carried out under the action of a catalyst;
[0018] The catalyst is at least one of water, sodium methoxide, antimony trioxide, sodium antimonate, aluminum trichloride, titanium tetrachloride, tetrabutyl titanate, tetraisopropyl titanate, zinc chloride, dibutyltin dilaurate, aluminum trichloride, potassium carbonate, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium bicarbonate, and sodium bicarbonate.
[0019] The molar amount of the catalyst is 0.1 to 10 times the molar amount of the aliphatic diamine shown in Formula A.
[0020] Preferably, in step S1, the reaction temperature is 40~150℃ and the time is 0.5~48h.
[0021] Preferably, in step S1, the molar ratio of the aliphatic diamine shown in formula A to the carbonate diester compound shown in formula B is 1:(2~100).
[0022] Preferably, in step S2:
[0023] The thermal decomposition reaction is carried out in the presence of a catalyst.
[0024] The catalyst is preferably at least one of silver acetate, zinc acetate, copper acetate, cobalt acetate, bismuth oxide, aluminum oxide, zinc oxide, cerium oxide, chromium oxide, calcium oxide, iron oxide, copper oxide, zinc silicate, zirconium silicate, and chromium silicate.
[0025] The amount of catalyst used is 1% to 20% of the molar amount of the aliphatic dicarboxylate compound shown in Formula C.
[0026] Preferably, in step S2:
[0027] The thermal decomposition reaction is carried out in a solvent medium;
[0028] The solvent is a high-boiling-point solvent;
[0029] The high-boiling-point solvent is at least one of the following: dioctyl sebacate, diethyl sebacate, dibutyl phthalate, dimethyl phthalate, dimethyl sulfoxide, sulfolane, o-dichlorobenzene, triethyl phosphate, diphenyl ether, dimethylformamide, dibenzyl ether, o-nitrotoluene, mesitylene, biphenyl, benzophenone, biphenyl diglycidyl ether, polydiethanolamide, and benzyl phenyl ether.
[0030] The molar ratio of the aliphatic dicarbamate compound shown in Formula C to the solvent is 1:(2~150).
[0031] Preferably, in step S2, the temperature of the thermal decomposition reaction is above 160°C; and the pressure of the thermal decomposition reaction is less than standard atmospheric pressure.
[0032] Preferably, in step S2, the temperature of the thermal decomposition reaction is 180~320℃; and the pressure of the thermal decomposition reaction is 20~90KPa.
[0033] The preparation method provided by this invention is a non-phosgene method, which utilizes aliphatic diamines and carbonate diesters to synthesize pure aliphatic dicarboxylate in a green manner. The aliphatic dicarboxylate is then pyrolyzed to aliphatic diisocyanate and fatty alcohol. This method provides pyrolysis raw materials, and the resulting alcohols or phenols can be recycled to synthesize carbonate diesters, reducing waste emissions and improving atom utilization. Furthermore, this pyrolysis route for isocyanate preparation avoids the use of highly toxic phosgene (i.e., aliphatic diamines can be converted to aliphatic diisocyanates without the use of phosgene) and does not produce corrosive HCl gas, reducing equipment corrosion and waste gas treatment pressure. In addition, the non-phosgene method of this invention ensures that the aliphatic diisocyanate product is free of chlorine residue and has extremely high purity. It can be applied on a large scale in industry and will become an effective method for future isocyanate preparation. Attached Figure Description
[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0035] Figure 1 The 1H NMR spectrum of methyl hexamethylenedicarbamate obtained in step S1 of Example 4 of this invention;
[0036] Figure 2 The hydrogen NMR spectrum of the reaction stock solution obtained in step S2 of Example 4 of this invention;
[0037] Figure 3 The image shows the 1H NMR spectrum of hexamethylene diisocyanate obtained after distillation and purification of the reaction stock solution in step S2 of Example 4 of this invention. Detailed Implementation
[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.
[0039] In this article, the technical features described in an open-ended manner include both closed technical solutions composed of the listed features and open technical solutions that include the listed features.
[0040] The term “and / or” as used herein includes any and all combinations of one or more of the related listed items.
[0041] In this document, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values of the range, as well as every value between the minimum and maximum values. Furthermore, when a range refers to an integer, it includes every integer between the minimum and maximum values of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.
[0042] In this article, when referring to units for data ranges, if the unit is only followed by the right endpoint, it means that the units for the left and right endpoints are the same. For example, 40~150℃ means that the units for the left endpoint "40" and the right endpoint "150" are both in degrees Celsius.
[0043] This invention provides a method for preparing aliphatic diisocyanates without phosgene, comprising the following steps:
[0044] S1. The aliphatic diamine shown in formula A reacts with the carbonate diester compound shown in formula B to form the aliphatic dicarbamate compound shown in formula C.
[0045] S2. The aliphatic dicarboxylate compound of formula C obtained in step S1 is subjected to thermal decomposition reaction to obtain the aliphatic diisocyanate of formula I.
[0046] Formula A; Formula B;
[0047] Formula C;
[0048] Formula I;
[0049] in:
[0050] R is -(CH2) n -;
[0051] R1 is an alkane group or an aromatic group.
[0052] The preparation method provided by this invention uses a carbonate diester compound and an aliphatic diamine to synthesize an aliphatic dicarboxylate compound, and then pyrolyzes the aliphatic dicarboxylate into an aliphatic diisocyanate and a fatty alcohol. This method is a low-cost, environmentally friendly synthesis method for converting aliphatic diamines into aliphatic diisocyanates without the use of phosgene, and provides a possibility for large-scale industrial production of isocyanates without phosgene in the future.
[0053] Regarding step S1 :
[0054] S1. The aliphatic diamine shown in Formula A reacts with the carbonate diester compound shown in Formula B to form the aliphatic dicarboxylate compound shown in Formula C.
[0055] The synthetic route for step S1 is as follows:
[0056]
[0057] In this invention, in the aliphatic diamine represented by formula A, R is -(CH2). n -; wherein, n is preferably 2 to 12, specifically 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12. More preferably, the aliphatic diamine shown in Formula A is selected from at least one of ethylenediamine, propylenediamine, butanediamine, pentanediamine, hexanediamine, heptamethamine, octanediamine, nonanediamine, decanediamine, and dodecyldiamine.
[0058] In this invention, in the carbonate diester compound shown in Formula B, R1 is an alkane group or an aromatic group. Preferably, the alkane group is a C1-C6 alkane group. Preferably, the aromatic group is phenyl. More preferably, in this invention, the carbonate diester compound shown in Formula B is selected from at least one of dimethyl carbonate, diethyl carbonate, dibutyl carbonate, dihexyl carbonate, and diphenyl carbonate.
[0059] In this invention, the molar ratio of the aliphatic diamine shown in Formula A to the carbonate diester compound shown in Formula B is preferably 1:(2~100), specifically 1:2, 1:5, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, 1:55, 1:60, 1:65, 1:70, 1:75, 1:80, 1:85, 1:90, 1:95, 1:100, etc.
[0060] In this invention, the reaction is preferably carried out under the action of a catalyst. The catalyst is preferably at least one selected from water, sodium methoxide, antimony trioxide, sodium antimonate, aluminum trichloride, titanium tetrachloride, tetrabutyl titanate, tetraisopropyl titanate, zinc chloride, dibutyltin dilaurate, aluminum trichloride, potassium carbonate, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium bicarbonate, and sodium bicarbonate. The molar amount of the catalyst is preferably 0.1 to 10 times the molar amount of the aliphatic diamine shown in Formula A, specifically 0.1, 0.25, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 times.
[0061] In this invention, the reaction temperature is above 20°C, preferably 40~150°C, specifically 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, etc. The reaction time is preferably 0.5~48h, specifically 0.5h, 1h, 2h, 4h, 8h, 12h, 16h, 20h, 24h, 28h, 32h, 36h, 40h, 44h, 48h. In this invention, the reaction is preferably accompanied by stirring. Through the above reaction, an aliphatic dicarboxylate compound of formula C is formed in the system, and alcohol or phenolic byproducts are also produced.
[0062] In this invention, after the reaction, the resulting reaction solution is preferably post-treated. The post-treatment preferably includes rotary evaporation, washing, and drying. Rotary evaporation is used to remove the catalyst and simultaneously remove alcohol or phenolic byproducts. Washing is preferably done with deionized water. After washing, the solid product is collected and dried. Drying is preferably vacuum drying. After post-treatment, a solid product of an aliphatic dicarboxylate compound of formula C is obtained. In this invention, the purity of the obtained solid product of the aliphatic dicarboxylate compound of formula C reaches 99% or higher.
[0063] Regarding step S2 :
[0064] S2. The aliphatic dicarboxylate compound of formula C obtained in step S1 is subjected to thermal decomposition reaction to obtain the aliphatic diisocyanate of formula I.
[0065] The reaction route for step S2 is as follows:
[0066]
[0067] In this invention, the thermal decomposition reaction is preferably carried out under the action of a catalyst. The catalyst is preferably at least one selected from silver acetate, zinc acetate, copper acetate, cobalt acetate, bismuth oxide, aluminum oxide, zinc oxide, cerium oxide, chromium oxide, calcium oxide, iron oxide, copper oxide, zinc silicate, zirconium silicate, and chromium silicate. The amount of catalyst used is preferably 1% to 20% of the molar amount of the aliphatic dicarboxylate compound shown in Formula C, specifically 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, etc.
[0068] In this invention, the thermal decomposition reaction is preferably carried out in a solvent medium. The solvent is preferably a high-boiling-point solvent, more preferably at least one selected from the following: dioctyl sebacate, diethyl sebacate, dibutyl phthalate, dimethyl phthalate, dimethyl sulfoxide, sulfolane, o-dichlorobenzene, triethyl phosphate, diphenyl ether, dimethylformamide, dibenzyl ether, o-nitrotoluene, mesitylene, biphenyl, benzophenone, biphenyl diglycidyl ether, polydiethanolamide, and benzyl phenyl ether. In this invention, the molar ratio of the aliphatic dicarboxylate compound shown in Formula C to the solvent is preferably 1:(2~150), specifically 1:2, 1:5, 1:10, 1:20, 1:30, 1:40, 1:50, 1:60, 1:70, 1:80, 1:90, 1:100, 1:110, 1:120, 1:130, 1:140, 1:150, etc.
[0069] In this invention, the temperature of the thermal decomposition reaction is above 160°C, preferably 180~320°C, and specifically can be 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, 310°C, 320°C, etc. The reaction time is preferably 0.1~24h, and specifically can be 0.1h, 1h, 2h, 4h, 8h, 12h, 16h, 20h, 24h, etc.
[0070] In this invention, the pressure of the thermal decomposition reaction is less than standard atmospheric pressure, preferably 20~90 kPa, specifically 20 kPa, 30 kPa, 40 kPa, 20 kPa, 30 kPa, 40 kPa, 50 kPa, 60 kPa, 70 kPa, 80 kPa, 90 kPa, etc. In this invention, the thermal decomposition reaction is preferably accompanied by stirring. Through the above thermal decomposition reaction, the alkoxy and amino hydrogen atoms in the raw material undergo a combined elimination reaction, which can decompose the dicarboxylate into diisocyanate and fatty alcohol. Therefore, the system forms the aliphatic diisocyanate and fatty alcohol shown in Formula I.
[0071] In this invention, after the above-mentioned thermal pyrolysis reaction, the resulting reaction solution is preferably post-treated. The post-treatment is preferably distillation purification, collecting the distilled droplets to obtain the aliphatic diisocyanate shown in Formula I. The remaining fatty alcohol after product collection can be recycled to synthesize diester compounds.
[0072] The preparation method provided by this invention is a non-phosgene method, which utilizes aliphatic diamines and carbonate diesters to synthesize pure aliphatic dicarboxylate in a green manner. The aliphatic dicarboxylate is then pyrolyzed to aliphatic diisocyanate and fatty alcohol. This method provides pyrolysis raw materials, and the resulting alcohols or phenols can be recycled to synthesize carbonate diesters, reducing waste emissions and improving atom utilization. Furthermore, this pyrolysis route for isocyanate preparation avoids the use of highly toxic phosgene (i.e., aliphatic diamines can be converted to aliphatic diisocyanates without the use of phosgene) and does not produce corrosive HCl gas, reducing equipment corrosion and waste gas treatment pressure. In addition, the non-phosgene method of this invention ensures that the aliphatic diisocyanate product is free of chlorine residue and has extremely high purity. It can be applied on a large scale in industry and will become an effective method for future isocyanate preparation.
[0073] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.
[0074] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods. All instruments are conventionally selected in the art.
[0075] Example 1
[0076] S1. Pentylene diamine, dimethyl carbonate, and sodium methoxide catalyst (molar ratio: pentylene diamine: dimethyl carbonate: sodium methoxide = 1:40:0.25) were added to a single-necked round-bottom flask equipped with a magnetic stirrer, and a reflux condenser was added above the flask neck. The round-bottom flask was placed in an oil bath equipped with a magnetic stirrer, and the reaction temperature was controlled at 80℃, the magnetic stirring speed was 400 rpm, and the reaction was continued for 12 hours. After the reaction was completed, the single-necked flask was placed on a rotary evaporator, the temperature was set to 60℃, and the evaporation was carried out for 20 minutes. Then, the product in the single-necked flask was washed with deionized water, the solid product was collected by vacuum filtration, and then placed in a vacuum drying oven, the temperature was set to 70℃, and the product was dried for 24 hours to obtain methyl pentylene dicarboxylate, with a yield of 98%. The purity of the dried solid product was detected by 1H NMR spectroscopy, and the product purity was >99%.
[0077] S2. The methyl pentanedicarbamate obtained in step S1, dioctyl sebacate as solvent, and cobalt acetate as catalyst (molar ratio: methyl pentanedicarbamate: dioctyl sebacate: cobalt acetate = 1:10:0.05) were added to a single-necked round-bottom flask equipped with a high-temperature magnetic stirrer. A cold trap was connected to the top of the flask, and the cold trap was connected to a vacuum diaphragm pump. The round-bottom flask was placed in a metal bath equipped with a magnetic stirrer. The reaction temperature was controlled at 220°C, the magnetic stirring speed at 400 rpm, and the vacuum pump pressure at 40 kPa. The reaction was continued for 3 hours. After the reaction was completed, the liquid was analyzed by 1H NMR spectroscopy, and the yield of pentanediisocyanate was calculated to be 65%. The reaction solution was distilled under reduced pressure at 170°C using an oil pump. The distilled droplets were collected, and the purity of pentanediisocyanate was determined by 1H NMR spectroscopy to be >99%.
[0078] Example 2
[0079] S1. Pentylene diamine, diethyl carbonate, and potassium carbonate catalyst (molar ratio: pentylene diamine: diethyl carbonate: potassium carbonate = 1:10:0.25) were added to a single-necked round-bottom flask equipped with a magnetic stirrer, and a reflux condenser was added above the flask neck. The round-bottom flask was placed in an oil bath equipped with a magnetic stirrer, and the reaction temperature was controlled at 90℃, the magnetic stirring speed was 400 rpm, and the reaction was continued for 24 h. After the reaction was completed, the single-necked flask was placed on a rotary evaporator, the temperature was set to 60℃, and the evaporation was carried out for 20 minutes. Then the product in the single-necked flask was washed with deionized water, the solid product was collected by vacuum filtration, and then placed in a vacuum drying oven, the temperature was set to 70℃, and the product was dried for 24 h to obtain ethyl pentylene dicarboxylate, with a yield of 79%. The purity of the dried solid product was detected by 1H NMR spectroscopy, and the product purity was >99%.
[0080] S2. The ethyl pentanedicarbamate obtained in step S1, dioctyl sebacate solvent, and silver acetate catalyst (molar ratio: ethyl pentanedicarbamate: dioctyl sebacate: silver acetate = 1:20:0.05) were added to a single-necked round-bottom flask equipped with a high-temperature magnetic stirrer. A cold trap was connected to the top of the flask, and the cold trap was connected to a vacuum diaphragm pump. The round-bottom flask was placed in a metal bath equipped with a magnetic stirrer. The reaction temperature was controlled at 190°C, the magnetic stirring speed was 400 rpm, and the vacuum pump pressure was set to 20 kPa. The reaction was continued for 3 hours. After the reaction was completed, the liquid was analyzed by 1H NMR spectroscopy. The yield of pentanediisocyanate was calculated to be 29% (the solvent used in this example has a high boiling point, but it is not a good electron donor and is not conducive to proton absorption (hydrogen desorption reaction), thus reducing the reaction yield). The reaction stock solution was distilled under reduced pressure using an oil pump at 170°C. The distilled droplets were collected, and the purity of glutaryl isocyanate was determined to be >99% by nuclear magnetic resonance hydrogen spectroscopy.
[0081] Example 3
[0082] S1. Pentylene diamine, diphenyl carbonate, and sodium bicarbonate catalyst (molar ratio: pentylene diamine: diphenyl carbonate: sodium bicarbonate = 1:10:0.5) were added to a single-necked round-bottom flask equipped with a magnetic stirrer, and a reflux condenser was added above the flask neck. The round-bottom flask was placed in an oil bath equipped with a magnetic stirrer, and the reaction temperature was controlled at 100℃, the magnetic stirring speed was 400 rpm, and the reaction was continued for 24 h. After the reaction was completed, the single-necked flask was placed on a rotary evaporator, the temperature was set to 60℃, and the evaporation was carried out for 20 minutes. Then, the product in the single-necked flask was washed with deionized water, the solid product was collected by vacuum filtration, and then placed in a vacuum drying oven, the temperature was set to 70℃, and the product was dried for 24 h to obtain phenyl pentylene dicarboxylate, with a yield of 45%. The purity of the dried solid product was detected by 1H NMR spectroscopy, and the product purity was >99%.
[0083] S2. The phenyl pentanedicarbamate obtained in step S1, the solvent o-dichlorobenzene, and the catalyst silver acetate (molar ratio: phenyl pentanedicarbamate: o-dichlorobenzene: silver acetate = 1:20:0.05) were added to a single-necked round-bottom flask equipped with a high-temperature resistant magnetic stirrer. A cold trap was connected to the top of the flask, and the cold trap was connected to a vacuum diaphragm pump. The round-bottom flask was placed in a metal bath equipped with a magnetic stirrer. The reaction temperature was controlled at 200℃, the magnetic stirring speed at 400 rpm, and the vacuum pump pressure at 60 kPa. The reaction was continued for 3 hours. After the reaction was completed, the liquid was analyzed by 1H NMR spectroscopy, and the yield of pentanediisocyanate was calculated to be 67%. The reaction solution was distilled under reduced pressure at 170℃ using an oil pump, and the distilled droplets were collected. The purity of pentanediisocyanate was determined by 1H NMR spectroscopy to be >99%.
[0084] Example 4
[0085] S1. Hexamethylenediamine, dimethyl carbonate, and water (molar ratio: hexamethylenediamine: dimethyl carbonate: water = 1:4:10) were added to a single-necked round-bottom flask equipped with a magnetic stirrer. A reflux condenser was added above the flask neck. The round-bottom flask was placed in an oil bath equipped with a magnetic stirrer, and the reaction temperature was controlled at 80℃, the magnetic stirring speed was 400 rpm, and the reaction was continued for 24 hours. After the reaction was completed, the single-necked flask was placed on a rotary evaporator, the temperature was set to 60℃, and the evaporation was carried out for 20 minutes. Then, the product in the single-necked flask was washed with deionized water, the solid product was collected by vacuum filtration, and then placed in a vacuum drying oven, the temperature was set to 70℃, and the product was dried for 24 hours to obtain methyl hexamethylenedicarbamate (i.e., hexamethylenedicarbamate), with a yield of 88%. The purity of the dried solid product was >99% by 1H NMR spectroscopy, and its 1H NMR spectrum is as follows. Figure 1 As shown.
[0086] S2. The methyl hexamethylenedicarbamate obtained in step S1, dimethyl phthalate as solvent, and zinc acetate as catalyst (molar ratio: methyl hexamethylenedicarbamate: dimethyl phthalate: zinc acetate = 1:50:0.01) are added to a single-necked round-bottom flask equipped with a high-temperature magnetic stirrer. A cold trap is connected to the top of the flask, and the cold trap is connected to a vacuum diaphragm pump. The round-bottom flask is placed in a metal bath equipped with a magnetic stirrer. The reaction temperature is controlled at 260℃, the magnetic stirring speed is 400 rpm, and the vacuum pump pressure is set to 30 kPa. The reaction is continued for 1 hour. After the reaction is completed, the 1H NMR spectrum of the liquid after the reaction is detected by nuclear magnetic resonance spectroscopy (as shown in Figure 1). Figure 2 As shown in the figure), the yield of hexamethylene diisocyanate (i.e., hexamethylene diisocyanate) was calculated to be 95%. The reaction solution was distilled under reduced pressure at 180°C using an oil pump, and the distilled droplets were collected. The purity of hexamethylene diisocyanate was determined to be >99% by nuclear magnetic resonance (NMR) spectroscopy, and its NMR spectrum is shown in the figure. Figure 3 As shown.
[0087] Example 5
[0088] S1. Hexamethylenediamine, diethyl carbonate, and titanium tetrachloride catalyst (molar ratio: hexamethylenediamine: diethyl carbonate: titanium tetrachloride = 1:10:0.5) were added to a single-necked round-bottom flask equipped with a magnetic stirrer, and a reflux condenser was added above the flask neck. The round-bottom flask was placed in an oil bath equipped with a magnetic stirrer, and the reaction temperature was controlled at 90℃, the magnetic stirring speed was 400 rpm, and the reaction was continued for 6 hours. After the reaction was completed, the single-necked flask was placed on a rotary evaporator, the temperature was set to 60℃, and the evaporation was carried out for 20 minutes. Then, the product in the single-necked flask was washed with deionized water, the solid product was collected by vacuum filtration, and then placed in a vacuum drying oven, the temperature was set to 70℃, and the product was dried for 24 hours to obtain ethyl hexamethylenedicarbamate, with a yield of 88%. The purity of the dried solid product was detected by 1H NMR spectroscopy, and the product purity was >99%.
[0089] S2. The ethyl hexamethylenedicarbamate obtained in step S1, dibutyl phthalate as solvent, and zinc oxide as catalyst (molar ratio: ethyl hexamethylenedicarbamate: dibutyl phthalate: zinc oxide = 1:50:0.01) were added to a single-necked round-bottom flask equipped with a high-temperature resistant magnetic stirrer. A cold trap was connected to the top of the flask, and the cold trap was connected to a vacuum diaphragm pump. The round-bottom flask was placed in a metal bath equipped with a magnetic stirrer. The reaction temperature was controlled at 270℃, the magnetic stirring speed at 400 rpm, and the vacuum pump pressure at 40 kPa. The reaction was continued for 2 hours. After the reaction was completed, the liquid was analyzed by 1H NMR spectroscopy, and the yield of hexamethylenediisocyanate was calculated to be 74%. The reaction solution was distilled under reduced pressure at 180℃ using an oil pump, and the distilled droplets were collected. The purity of hexamethylenediisocyanate was determined by 1H NMR spectroscopy to be >99%.
[0090] Example 6
[0091] S1. Hexamethylenediamine, diphenyl carbonate, and dibutyltin dilaurate (molar ratio: hexamethylenediamine: diphenyl carbonate: dibutyltin dilaurate = 1:10:0.25) were added to a single-necked round-bottom flask equipped with a magnetic stirrer, and a reflux condenser was added above the flask neck. The round-bottom flask was placed in an oil bath equipped with a magnetic stirrer, and the reaction temperature was controlled at 100℃, the magnetic stirring speed was 400 rpm, and the reaction was continued for 12 hours. After the reaction was completed, the single-necked flask was placed on a rotary evaporator, the temperature was set to 60℃, and the evaporation was carried out for 20 minutes. Then, the product in the single-necked flask was washed with deionized water, the solid product was collected by vacuum filtration, and then placed in a vacuum drying oven at 70℃ for 24 hours to obtain phenyl hexamethylenedicarbamate, with a yield of 48%. The purity of the dried solid product was detected by 1H NMR spectroscopy, and the product purity was >99%.
[0092] S2. The phenyl hexamethylenedicarbamate obtained in step S1, dibenzyl ether solvent, and zirconium oxide catalyst (molar ratio: ethyl hexamethylenedicarbamate: dibenzyl ether: zirconium oxide = 1:30:0.1) were added to a single-necked round-bottom flask equipped with a high-temperature resistant magnetic stirrer. A cold trap was connected to the top of the flask, and the cold trap was connected to a vacuum diaphragm pump. The round-bottom flask was placed in a metal bath equipped with a magnetic stirrer. The reaction temperature was controlled at 240℃, the magnetic stirring speed at 400 rpm, and the vacuum pump pressure at 20 kPa. The reaction was continued for 3 hours. After the reaction was completed, the liquid was analyzed by 1H NMR spectroscopy, and the yield of hexamethylenediisocyanate was calculated to be 64%. The reaction solution was distilled under reduced pressure at 180℃ using an oil pump. The distilled droplets were collected, and the purity of hexamethylenediisocyanate was determined by 1H NMR spectroscopy to be >99%.
[0093] Example 7
[0094] S1. Octanediamine, dimethyl carbonate, and sodium hydroxide catalyst (molar ratio: octanediamine:dimethyl carbonate:sodium hydroxide = 1:6:1) were added to a single-necked round-bottom flask equipped with a magnetic stirrer, and a reflux condenser was added above the flask neck. The round-bottom flask was placed in an oil bath equipped with a magnetic stirrer, and the reaction temperature was controlled at 80℃, the magnetic stirring speed was 400 rpm, and the reaction was continued for 12 h. After the reaction was completed, the single-necked flask was placed on a rotary evaporator, the temperature was set to 60℃, and the evaporation was carried out for 20 minutes. Then the product in the single-necked flask was washed with deionized water, the solid product was collected by vacuum filtration, and then placed in a vacuum drying oven, the temperature was set to 70℃, and the product was dried for 24 h to obtain methyl octanedicarbamate, with a yield of 68%. The purity of the dried solid product was detected by 1H NMR spectroscopy, and the product purity was >99%.
[0095] S2. The methyl octyl dicarboxylate obtained in step S1, diphenyl ether as solvent, and alumina as catalyst (molar ratio: methyl octyl dicarboxylate: diphenyl ether: alumina = 1:20:0.05) were added to a single-necked round-bottom flask equipped with a high-temperature magnetic stirrer. A cold trap was connected to the top of the flask, and the cold trap was connected to a vacuum diaphragm pump. The round-bottom flask was placed in a metal bath equipped with a magnetic stirrer. The reaction temperature was controlled at 230°C, the magnetic stirring speed at 400 rpm, and the vacuum pump pressure at 30 kPa. The reaction was continued for 3 hours. After the reaction was completed, the liquid was analyzed by 1H NMR spectroscopy, and the yield of octyl diisocyanate was calculated to be 64%. The reaction solution was distilled under reduced pressure at 200°C using an oil pump. The distilled droplets were collected, and the purity of octyl diisocyanate was determined by 1H NMR spectroscopy to be >99%.
[0096] Example 8
[0097] S1. Octanediamine, diethyl carbonate, and potassium hydroxide catalyst (molar ratio: octanediamine:diethyl carbonate:potassium hydroxide = 1:6:2) were added to a single-necked round-bottom flask equipped with a magnetic stirrer, and a reflux condenser was added above the flask neck. The round-bottom flask was placed in an oil bath equipped with a magnetic stirrer, and the reaction temperature was controlled at 90℃, the magnetic stirring speed was 400 rpm, and the reaction was continued for 24 h. After the reaction was completed, the single-necked flask was placed on a rotary evaporator, the temperature was set to 60℃, and the evaporation was carried out for 20 minutes. Then, the product in the single-necked flask was washed with deionized water, the solid product was collected by vacuum filtration, and then placed in a vacuum drying oven, the temperature was set to 70℃, and the product was dried for 24 h to obtain octanedicarbamate with a yield of 65%. The purity of the dried solid product was detected by 1H NMR spectroscopy, and the product purity was >99%.
[0098] S2. The ethyl octyl dicarboxylate obtained in step S1, dimethyl sulfoxide (DMSO) solvent, and zinc silicate catalyst (molar ratio: ethyl octyl dicarboxylate: DMSO: zinc silicate = 1:10:0.1) were added to a single-necked round-bottom flask equipped with a high-temperature magnetic stirrer. A cold trap was connected to the top of the flask, and the cold trap was connected to a vacuum diaphragm pump. The round-bottom flask was placed in a metal bath equipped with a magnetic stirrer. The reaction temperature was controlled at 250°C, the magnetic stirring speed at 400 rpm, and the vacuum pump pressure at 30 kPa. The reaction was continued for 2 hours. After the reaction was completed, the liquid was analyzed by 1H NMR spectroscopy, and the yield of octyl diisocyanate was calculated to be 57%. The reaction solution was distilled under reduced pressure at 200°C using an oil pump. The distilled droplets were collected, and the purity of octyl diisocyanate was determined by 1H NMR spectroscopy to be >99%.
[0099] Example 9
[0100] S1. Hexamethylenediamine, dimethyl carbonate, and water (molar ratio: hexamethylenediamine: dimethyl carbonate: water = 1:6:10) were added to a single-necked round-bottom flask equipped with a magnetic stirrer, and a reflux condenser was added above the flask neck. The round-bottom flask was placed in an oil bath equipped with a magnetic stirrer, and the reaction temperature was controlled at 80℃, the magnetic stirring speed was 400 rpm, and the reaction was continued for 12 hours. After the reaction was completed, the single-necked flask was placed on a rotary evaporator, the temperature was set to 60℃, and the evaporation was carried out for 20 minutes. Then, the product in the single-necked flask was washed with deionized water, the solid product was collected by vacuum filtration, and then placed in a vacuum drying oven, the temperature was set to 70℃, and the product was dried for 24 hours to obtain methyl hexamethylenedicarbamate, with a yield of 66%. The purity of the dried solid product was detected by 1H NMR spectroscopy, and the product purity was >99%.
[0101] S2. The methyl hexamethylenedicarbamate obtained in step S1, dimethyl phthalate as solvent, and zinc acetate as catalyst (molar ratio: methyl hexamethylenedicarbamate: dimethyl phthalate: zinc acetate = 1:50:0.05) were added to a single-necked round-bottom flask equipped with a high-temperature resistant magnetic stirrer. A cold trap was connected to the top of the flask, and the cold trap was connected to a vacuum diaphragm pump. The round-bottom flask was placed in a metal bath equipped with a magnetic stirrer. The reaction temperature was controlled at 260℃, the magnetic stirring speed at 400 rpm, and the vacuum pump pressure at 30 kPa. The reaction was continued for 1 hour. After the reaction was completed, the liquid was analyzed by 1H NMR spectroscopy, and the yield of hexamethylenediisocyanate was calculated to be 80%. The reaction solution was distilled under reduced pressure at 180℃ using an oil pump, and the distilled droplets were collected. The purity of hexamethylenediisocyanate was determined by 1H NMR spectroscopy to be >99%.
[0102] Example 10
[0103] S1. Hexamethylenediamine, dimethyl carbonate, and water (molar ratio: hexamethylenediamine: dimethyl carbonate: water = 1:4:10) were added to a single-necked round-bottom flask equipped with a magnetic stirrer, and a reflux condenser was added above the flask neck. The round-bottom flask was placed in an oil bath equipped with a magnetic stirrer, and the reaction temperature was controlled at 80℃, the magnetic stirring speed was 400 rpm, and the reaction was continued for 3 hours. After the reaction was completed, the single-necked flask was placed on a rotary evaporator, the temperature was set to 60℃, and the evaporation was carried out for 20 minutes. Then, the product in the single-necked flask was washed with deionized water, the solid product was collected by vacuum filtration, and then placed in a vacuum drying oven, the temperature was set to 70℃, and the product was dried for 24 hours to obtain methyl hexamethylenedicarbamate, with a yield of 45%. The purity of the dried solid product was detected by 1H NMR spectroscopy, and the product purity was >99%.
[0104] S2. The methyl hexamethylenedicarbamate obtained in step S1, dimethyl phthalate as solvent, and zinc acetate as catalyst (molar ratio: methyl hexamethylenedicarbamate: dimethyl phthalate: zinc acetate = 1:50:0.1) were added to a single-necked round-bottom flask equipped with a high-temperature resistant magnetic stirrer. A cold trap was connected to the top of the flask, and the cold trap was connected to a vacuum diaphragm pump. The round-bottom flask was placed in a metal bath equipped with a magnetic stirrer. The reaction temperature was controlled at 260℃, the magnetic stirring speed at 400 rpm, and the vacuum pump pressure at 30 kPa. The reaction was continued for 1 hour. After the reaction was completed, the liquid was analyzed by 1H NMR spectroscopy, and the yield of hexamethylenediisocyanate was calculated to be 55%. The reaction solution was distilled under reduced pressure at 180℃ using an oil pump. The distilled droplets were collected, and the purity of hexamethylenediisocyanate was determined by 1H NMR spectroscopy to be >99%.
[0105] Example 11
[0106] S1. Hexamethylenediamine, diethyl carbonate, and sodium methoxide (molar ratio: hexamethylenediamine: diethyl carbonate: sodium methoxide = 1:40:0.1) were added to a single-necked round-bottom flask equipped with a magnetic stirrer, and a reflux condenser was added above the flask neck. The round-bottom flask was placed in an oil bath equipped with a magnetic stirrer, and the reaction temperature was controlled at 80℃, the magnetic stirring speed was 400 rpm, and the reaction was continued for 0.5 h. After the reaction was completed, the single-necked flask was placed on a rotary evaporator, the temperature was set to 60℃, and the evaporation was carried out for 20 minutes. Then the product in the single-necked flask was washed with deionized water, the solid product was collected by vacuum filtration, and then placed in a vacuum drying oven, the temperature was set to 70℃, and the product was dried for 24 h to obtain ethyl hexamethylenedicarbamate, with a yield of 94%. The purity of the dried solid product was detected by 1H NMR spectroscopy, and the product purity was >99%.
[0107] S2. The ethyl hexamethylenedicarbamate obtained in step S1, dibutyl phthalate as solvent, and silver acetate as catalyst (molar ratio: ethyl hexamethylenedicarbamate: dibutyl phthalate: silver acetate = 1:50:0.01) were added to a single-necked round-bottom flask equipped with a high-temperature magnetic stirrer. A cold trap was connected to the top of the flask, and the cold trap was connected to a vacuum diaphragm pump. The round-bottom flask was placed in a metal bath equipped with a magnetic stirrer. The reaction temperature was controlled at 260℃, the magnetic stirring speed at 400 rpm, and the vacuum pump pressure at 30 kPa. The reaction was continued for 1 hour. After the reaction was completed, the liquid was analyzed by 1H NMR spectroscopy, and the yield of hexamethylenediisocyanate was calculated to be 77%. The reaction solution was distilled under reduced pressure at 180℃ using an oil pump. The distilled droplets were collected, and the purity of hexamethylenediisocyanate was determined by 1H NMR spectroscopy to be >99%.
[0108] Example 12
[0109] S1. Decanediamine, dimethyl carbonate, and aluminum trichloride catalyst (molar ratio: decanediamine: dimethyl carbonate: aluminum trichloride = 1:10:0.1) were added to a single-necked round-bottom flask equipped with a magnetic stirrer, and a reflux condenser was added above the flask neck. The round-bottom flask was placed in an oil bath equipped with a magnetic stirrer, and the reaction temperature was controlled at 80℃, the magnetic stirring speed was 400 rpm, and the reaction was continued for 12 hours. After the reaction was completed, the single-necked flask was placed on a rotary evaporator, the temperature was set to 60℃, and the evaporation was carried out for 20 minutes. Then, the product in the single-necked flask was washed with deionized water, the solid product was collected by vacuum filtration, and then placed in a vacuum drying oven, the temperature was set to 70℃, and the product was dried for 24 hours to obtain methyl decanedicarbamate, with a yield of 64%. The purity of the dried solid product was detected by 1H NMR spectroscopy, and the product purity was >99%.
[0110] S2. The methyl sebacate obtained in step S1, biphenyl solvent, and chromium oxide catalyst (molar ratio: methyl sebacate: biphenyl: chromium oxide = 1:20:0.1) were added to a single-necked round-bottom flask equipped with a high-temperature resistant magnetic stirrer. A cold trap was connected to the top of the flask, and the cold trap was connected to a vacuum diaphragm pump. The round-bottom flask was placed in a metal bath equipped with a magnetic stirrer. The reaction temperature was controlled at 260℃, the magnetic stirring speed at 400 rpm, and the vacuum pump pressure at 30 kPa. The reaction was continued for 3 hours. After the reaction was completed, the liquid was analyzed by 1H NMR spectroscopy, and the yield of sebacate was calculated to be 57%. The reaction solution was distilled under reduced pressure at 210℃ using an oil pump. The distilled droplets were collected, and the purity of sebacate was determined by 1H NMR spectroscopy to be >99%.
[0111] Example 13
[0112] S1. Hexamethylenediamine, diphenyl carbonate, and antimony trioxide catalyst (molar ratio: hexamethylenediamine: diphenyl carbonate: antimony trioxide = 1:10:0.25) were added to a single-necked round-bottom flask equipped with a magnetic stirrer, and a reflux condenser was added above the flask neck. The round-bottom flask was placed in an oil bath equipped with a magnetic stirrer, and the reaction temperature was controlled at 100℃, the magnetic stirring speed was 400 rpm, and the reaction was continued for 24 h. After the reaction was completed, the single-necked flask was placed on a rotary evaporator, the temperature was set to 60℃, and the evaporation was carried out for 20 minutes. Then, the product in the single-necked flask was washed with deionized water, the solid product was collected by vacuum filtration, and then placed in a vacuum drying oven, the temperature was set to 70℃, and the product was dried for 24 h to obtain phenyl hexamethylenedicarbamate, with a yield of 56%. The purity of the dried solid product was detected by 1H NMR spectroscopy, and the product purity was >99%.
[0113] S2. The phenyl hexamethylenedicarbamate obtained in step S1, the solvent poly(dimethyl glycolate), and the catalyst zinc acetate (molar ratio: phenyl hexamethylenedicarbamate:poly(dimethyl glycolate):zinc acetate = 1:10:0.1) were added to a single-necked round-bottom flask equipped with a high-temperature magnetic stirrer. A cold trap was connected to the top of the flask, and the cold trap was connected to a vacuum diaphragm pump. The round-bottom flask was placed in a metal bath equipped with a magnetic stirrer. The reaction temperature was controlled at 220°C, the magnetic stirring speed at 400 rpm, and the vacuum pump pressure at 10 kPa. The reaction was continued for 1 hour. After the reaction was completed, the liquid was analyzed by 1H NMR spectroscopy, and the yield of hexamethylenediisocyanate was calculated to be 85%. The reaction solution was distilled under reduced pressure at 180°C using an oil pump. The distilled droplets were collected, and the purity of hexamethylenediisocyanate was determined by 1H NMR spectroscopy to be >99%.
[0114] Example 14
[0115] S1. Hexamethylenediamine, dibutyl carbonate, and water (molar ratio: hexamethylenediamine: dibutyl carbonate: water = 1:4:10) were added to a single-necked round-bottom flask equipped with a magnetic stirrer, and a reflux condenser was added above the flask neck. The round-bottom flask was placed in an oil bath equipped with a magnetic stirrer, and the reaction temperature was controlled at 80℃, the magnetic stirring speed was 400 rpm, and the reaction was continued for 24 h. After the reaction was completed, the single-necked flask was placed on a rotary evaporator, the temperature was set to 60℃, and the evaporation was carried out for 20 minutes. Then the product in the single-necked flask was washed with deionized water, the solid product was collected by vacuum filtration, and then placed in a vacuum drying oven, the temperature was set to 70℃, and the product was dried for 24 h to obtain butyl hexamethylenedicarbamate, with a yield of 83%. The purity of the dried solid product was detected by 1H NMR spectroscopy, and the product purity was >99%.
[0116] S2. The butyl hexamethylenedicarbamate obtained in step S1, dimethyl phthalate as solvent, and zinc acetate as catalyst (molar ratio: butyl hexamethylenedicarbamate: dimethyl phthalate: zinc acetate = 1:70:0.01) were added to a single-necked round-bottom flask equipped with a high-temperature magnetic stirrer. A cold trap was connected to the top of the flask, and the cold trap was connected to a vacuum diaphragm pump. The round-bottom flask was placed in a metal bath equipped with a magnetic stirrer. The reaction temperature was controlled at 260℃, the magnetic stirring speed at 400 rpm, and the vacuum pump pressure at 20 kPa. The reaction was continued for 1 hour. After the reaction was completed, the liquid was analyzed by 1H NMR spectroscopy, and the yield of hexamethylenediisocyanate was calculated to be 98%. The reaction solution was distilled under reduced pressure at 180℃ using an oil pump, and the distilled droplets were collected. The purity of hexamethylenediisocyanate was determined by 1H NMR spectroscopy to be >99%.
[0117] Example 15
[0118] S1. Hexamethylenediamine, dihexyl carbonate, and titanium tetrachloride catalyst (molar ratio: hexamethylenediamine: dihexyl carbonate: titanium tetrachloride = 1:10:0.2) were added to a single-necked round-bottom flask equipped with a magnetic stirrer, and a reflux condenser was added above the flask neck. The round-bottom flask was placed in an oil bath equipped with a magnetic stirrer, and the reaction temperature was controlled at 100℃, the magnetic stirring speed was 400 rpm, and the reaction was continued for 24 h. After the reaction was completed, the single-necked flask was placed on a rotary evaporator, the temperature was set to 60℃, and the evaporation was carried out for 20 minutes. Then the product in the single-necked flask was washed with deionized water, the solid product was collected by vacuum filtration, and then placed in a vacuum drying oven, the temperature was set to 70℃, and the product was dried for 24 h to obtain hexamethylenedicarbamate, with a yield of 69%. The purity of the dried solid product was detected by 1H NMR spectroscopy, and the product purity was >99%.
[0119] S2. The hexamethylene hexanoate obtained in step S1, dimethylformamide solvent, and bismuth oxide catalyst (molar ratio: hexamethylene hexanoate: dimethylformamide: bismuth oxide = 1:40:0.1) were added to a single-necked round-bottom flask equipped with a high-temperature resistant magnetic stirrer. A cold trap was connected to the top of the flask, and the cold trap was connected to a vacuum diaphragm pump. The round-bottom flask was placed in a metal bath equipped with a magnetic stirrer. The reaction temperature was controlled at 210℃, the magnetic stirring speed at 400 rpm, and the vacuum pump pressure at 30 kPa. The reaction was continued for 3 hours. After the reaction was completed, the liquid was analyzed by 1H NMR spectroscopy, and the yield of hexamethylene diisocyanate was calculated to be 75%. The reaction solution was distilled under reduced pressure at 180℃ using an oil pump. The distilled droplets were collected, and the purity of hexamethylene diisocyanate was determined by 1H NMR spectroscopy to be >99%.
[0120] Example 16
[0121] S1. Dodecyl diamine, dimethyl carbonate, and sodium methoxide catalyst (molar ratio: dodecyl diamine: dimethyl carbonate: water = 1:10:1) were added to a single-necked round-bottom flask equipped with a magnetic stirrer, and a reflux condenser was added above the flask neck. The round-bottom flask was placed in an oil bath equipped with a magnetic stirrer, and the reaction temperature was controlled at 80℃, the magnetic stirring speed was 400 rpm, and the reaction was continued for 6 hours. After the reaction was completed, the single-necked flask was placed on a rotary evaporator, the temperature was set to 60℃, and the evaporation was carried out for 20 minutes. Then, the product in the single-necked flask was washed with deionized water, the solid product was collected by vacuum filtration, and then placed in a vacuum drying oven, the temperature was set to 70℃, and the product was dried for 24 hours to obtain methyl dodecyl dicarboxylate, with a yield of 93%. The purity of the dried solid product was detected by 1H NMR spectroscopy, and the product purity was >99%.
[0122] S2. The methyl dodecyl dicarboxylate obtained in step S1, dibutyl phthalate as solvent, and cerium oxide as catalyst (molar ratio: methyl dodecyl dicarboxylate: dibutyl phthalate: cerium oxide = 1:50:0.05) were added to a single-necked round-bottom flask equipped with a high-temperature magnetic stirrer. A cold trap was connected to the top of the flask, and the cold trap was connected to a vacuum diaphragm pump. The round-bottom flask was placed in a metal bath equipped with a magnetic stirrer. The reaction temperature was controlled at 260℃, the magnetic stirring speed at 400 rpm, and the vacuum pump pressure at 20 kPa. The reaction was continued for 2 hours. After the reaction was completed, the liquid was analyzed by 1H NMR spectroscopy, and the yield of dodecyl diisocyanate was calculated to be 85%. The reaction solution was distilled under reduced pressure at 180℃ using an oil pump, and the distilled droplets were collected. The purity of dodecyl diisocyanate was determined by 1H NMR spectroscopy to be >99%.
[0123] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of these embodiments are merely to aid in understanding the method and core ideas of the present invention, including the best mode, and to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements similar to those expressed in the claims, or if they include equivalent structural elements that are not substantially different from those expressed in the claims, then these other embodiments should also be included within the scope of the claims.
Claims
1. A process for the production of aliphatic diisocyanates by a non-phosgene route, characterized in that, The method comprises the following steps: S1, reacting an aliphatic diamine shown in formula A with a carbonic acid diester compound shown in formula B to form an aliphatic biscarbamic acid ester compound shown in formula C; S2, performing a thermal cracking reaction on the aliphatic biscarbamic acid ester compound shown in formula C obtained in step S1 to obtain an aliphatic diisocyanate shown in formula I; Formula A; Formula B; Formula C; Formula I; wherein: R is -(CH2) n -; R1 is an alkyl group or an aromatic hydrocarbon group.
2. The method of claim 1, wherein, In step S1, the aliphatic diamine shown in formula A is at least one selected from ethylenediamine, propylenediamine, butylenediamine, pentanediamine, hexanediamine, heptylenediamine, octanediamine, nonanediamine, decanediamine and dodecanediamine.
3. The method of claim 1, wherein, In step S1, the carbonic acid diester compound shown in formula B is at least one selected from dimethyl carbonate, diethyl carbonate, dibutyl carbonate, dihexyl carbonate and diphenyl carbonate.
4. The method of claim 1, wherein, In step S1, the reaction is performed under the action of a catalyst. The catalyst is at least one selected from water, sodium methoxide, antimony trioxide, sodium antimonate, aluminum trichloride, titanium tetrachloride, tetrabutyl titanate, tetraisopropyl titanate, zinc chloride, dibutyltin dilaurate, aluminum trichloride, potassium carbonate, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium bicarbonate and sodium bicarbonate. The molar amount of the catalyst is 0.1-10 times the molar amount of the aliphatic diamine shown in formula A.
5. The method of claim 1, wherein, In step S1, the reaction temperature is 40-150°C, and the reaction time is 0.5-48h.
6. The method of claim 1, wherein, In step S1, the molar ratio of the aliphatic diamine shown in formula A to the carbonic acid diester compound shown in formula B is 1:(2-100).
7. The method of claim 1, wherein, In step S2: The thermal cracking reaction is performed under the action of a catalyst. The catalyst is preferably at least one selected from silver acetate, zinc acetate, copper acetate, cobalt acetate, bismuth oxide, aluminum oxide, zinc oxide, cerium oxide, chromium oxide, calcium oxide, iron oxide, copper oxide, zinc silicate, zirconium silicate and chromium silicate. The amount of the catalyst is 1%-20% of the molar amount of the aliphatic biscarbamic acid ester compound shown in formula C.
8. The method of claim 1, wherein, In step S2: The thermal cracking reaction is performed in a solvent medium. The solvent is a high-boiling-point solvent. The high-boiling-point solvent is at least one selected from dioctyl sebacate, diethyl sebacate, dibutyl phthalate, dimethyl phthalate, dimethyl sulfoxide, sulfolane, o-dichlorobenzene, triethyl phosphate, diphenyl ether, dimethylformamide, dibenzyl ether, o-nitrotoluene, mesitylene, biphenyl, benzophenone, hydroquinone diglycidyl ether, polydiethylene glycol dimethyl ether and benzyl phenyl ether. The molar ratio of the aliphatic biscarbamic acid ester compound shown in formula C to the solvent is 1:(2-150).
9. The method of claim 1, wherein, In step S2, the temperature of the thermal cracking reaction is higher than 160°C; and the pressure of the thermal cracking reaction is less than the standard atmospheric pressure.
10. The method according to claim 1 or 9, characterized in that, In step S2, the temperature of the thermal cracking reaction is 180-320°C; and the pressure of the thermal cracking reaction is 20-90KPa.