A method for synthesizing adipamide and adiponitrile by a dehydroxylation method using 2-hydroxyadipamide as a raw material

Abstract

The present invention relates to a method for synthesizing adipamide and adiponitrile by a dehydroxylation method using 2-hydroxyadipamide as a raw material. The method comprises the following steps: adding 2-hydroxyadipamide, a solvent, and a catalyst (NiP, CoP, MoP, Mo3P, Mo2N, W2N, or MoS2) into a reaction kettle, sealing it, and introducing hydrogen at 1 to 6 Mpa, reacting at 100 to 250 °C for 1 to 30 h to obtain an adipamide product; after separating the obtained adipamide product, using acetonitrile as a dehydrating agent and a Pd-loaded solid acid catalyst (ZSM-5, SBA-15, Nb2O5, or TS-1) to dehydrate to obtain adiponitrile. The present invention has the characteristics of few by-products, easy separation, low cost, non-toxicity, and non-corrosion. It is a new route for the dehydroxylation synthesis of adipamide and adiponitrile from 2-hydroxyadipamide, having dual environmental and economic values and broad development prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical synthesis, and particularly relates to a new process for synthesizing adipamide and adiponitrile by a dehydroxylation method using 2-hydroxyadipamide as a raw material. Background Art

[0002] With the development of society, non-renewable petrochemical resources are decreasing day by day, and there is an urgent need to find a sustainable resource to replace petrochemical resources. As a renewable carbon resource, biomass is considered to be one of the most potential alternatives to fossil energy. Biomass raw materials can be converted into a variety of platform compounds through chemical methods and then catalytically upgraded into high-energy-density and high-value-added chemicals. We have prepared a class of green and safe "ionic liquid-based hydroxylamine salts", which solve the problems of environmental pollution and large safety hazards existing in traditional hydroxylamine salts, and successfully applied the ionic liquid-based hydroxylamine salts to the green synthesis of furandicarbonitrile (Chemical Communications, 2015, 51(10): 1930-1932; Journal of Molecular Liquids, 2022: 348; Chinese Journal of Chemical Engineering, 2022; CN103539742B[P]. 2015-08-05; RSC Advances, 2019, 9(31): 17631-17638), and the complete separation and recycling of ionic liquids can be achieved by using a simple phase separation method. On the basis of this research, using 5-hydroxymethylfurfural and ionic liquid-based hydroxylamine salt as the initial raw materials, furandicarboxamide is synthesized through furandicarbonitrile, and then ring-opening and value-added production of 2-hydroxyadipamide (CN115043796A, 2022-09-13). 2-Hydroxyadipamide is a precursor of adipamide, and adipamide can be efficiently prepared through a dehydroxylation reaction, and then adipamide is dehydrated to form adiponitrile. As an important organic chemical raw material, adiponitrile has a wide range of applications in the synthesis of nylon 6, nylon 66, synthetic rubber, etc. Therefore, the preparation of adiponitrile from the biomass platform compound 5-hydroxymethylfurfural as the starting material is a brand-new process route.

[0003] The reaction of 2-hydroxyadipamide dehydroxylation to form adipamide is an important chemical transformation. Most metal dehydroxylation processes require the use of stoichiometric amounts of metal reagents, which may be toxic, expensive, or difficult to remove from the deoxygenated products. For example, the deoxygenation of α-hydroxy aldehydes, ketones, or esters can be completed in one step through a SmI 2 -mediated reduction reaction. The main disadvantages of this method include the use of stoichiometric amounts of expensive samarium metal and the possible sensitivity to other groups that are sensitive to SmI 2The sensitive functional groups are reduced. In some cases (such as α-hydroxy esters), it may also be necessary to use the toxic HMPA to increase the reducing ability of the samarium reagent (John Wiley & Sons, Ltd, 2012). In addition, many functional groups, including nitriles, α,β-unsaturated ketones or alkyl halides, are sensitive to a large amount of SmI 2 reagents and may cause problems with chemoselectivity. The metal-free deoxygenation method uses stoichiometric molecular iodine, triphenylphosphine and a base to convert the deoxygenated product in the presence (European journal of organic chemistry, 2018(13):2018). Therefore, we developed a simple and efficient catalyst that does not require the use of stoichiometric catalysts and is easily separable and reusable after the reaction to solve the problem of the dehydroxylation of 2-hydroxyadipamide to form adipamide.

[0004] Furthermore, in the dehydration of adipamide to prepare adiponitrile, common amide dehydrating agents include phosphorus pentoxide, phosphorus pentachloride, phosphorus oxychloride, thionyl chloride, phosgene, p-toluenesulfonyl chloride, etc. Other dehydration systems include titanium tetrachloride-tertiary amine, triphenylphosphine-carbon tetrachloride-triethylamine, trichloroacetyl chloride-triethylamine, trifluoromethanesulfonic anhydride-triethylamine, dibutyltin oxide, etc. In addition, there are also a few catalytic methods reported. For example, under strong heat conditions, catalytic species such as aluminum oxide, silica, and aluminum phosphate are used, and molecular sieves are used as auxiliary water absorbers at the same time. CN104774160A discloses a preparation method of a cyclopropylmethyl cyanide derivative. This method uses cyclopropylformamide as a raw material and synthesizes cyclopropylmethyl cyanide under the action of a dehydrating agent. The dehydrating agent is selected from one of thionyl chloride, liquid phosgene, phosphorus pentoxide, and p-toluenesulfonyl chloride. In the above methods, the dehydrating agents used have problems such as toxicity, large corrosion to equipment, or complex product separation, and the heterogeneous reaction system also has problems such as poor stability or low reaction activity. Summary of the Invention

[0005] The object of the present invention is to propose a method for synthesizing adipamide by dehydroxylation using 2-hydroxyadipamide as a raw material, and after simple separation, adipamide is dehydrated to form adiponitrile for the technical problems existing in the current technology. This method uses 2-hydroxyadipamide as a raw material, adopts a transition metal nitride or phosphide as a catalyst, and uses a new process for synthesizing adipamide by dehydroxylation, which has the characteristics of few by-products, easy separation, and low cost. Adipamide is dehydrated to form adiponitrile by using acetonitrile as a dehydrating agent through Pd-loaded solid acid dehydration. This method has the characteristics of reusable catalyst, easy separation, and high product yield. This reaction route is a route with both environmental protection and economic value and has broad development prospects.

[0006] The present invention provides the following technical solutions:

[0007] A method for synthesizing adipamide by dehydroxylation using 2-hydroxyadipamide as a raw material, the method comprising the following steps:

[0008] Add 2-hydroxyadipamide, a solvent, and a catalyst into a reaction kettle, seal it, and introduce hydrogen at 1-6 Mpa, and react at 100-250 °C for 1-30 h to obtain an adipamide product;

[0009] In the reaction system, the concentration of 2-hydroxyadipamide is 0.01-1 mol / L.

[0010] The solvent is tetrahydrofuran, N,N-dimethylformamide, 1,4-dioxane, dichloromethane or 1,2-dimethoxyethane.

[0011] The catalyst is NiP, CoP, MoP, Mo 3 P, Mo 2 N, W 2 N or MoS 2 .

[0012] The mass ratio of the catalyst to 2-hydroxyadipamide is 1:2-2:1.

[0013] A method for synthesizing adiponitrile by dehydration using adipamide as a raw material, the method comprising the following steps:

[0014] Add acetonitrile, a catalyst, and the adipamide obtained by the above method into a reactor, and react at 80-150 °C for 1-30 h to obtain an adiponitrile product;

[0015] The concentration of the adipamide is 0.01-1 mol / L.

[0016] The catalyst is a Pd-supported solid acid catalyst, and the loading amount is 1%-5%.

[0017] The solid acid catalyst is ZSM-5, SBA-15, Nb 2 O 5 or TS-1.

[0018] The mass ratio of the catalyst to adipamide is 1:2-2:1.

[0019] The beneficial effects of the present invention are:

[0020] The present invention provides a new process for synthesizing adipamide by dehydroxylation using 2-hydroxyadipamide as a raw material. The hydroxyl group of 2-hydroxyadipamide is directly removed by a hydrogen reduction method without affecting the amide group. Finally, the highest yield of the adipamide product is 50.2%. After separation, adipamide is used as a dehydrating agent with acetonitrile to synthesize adiponitrile by a dehydration method, and the highest yield of synthesizing adiponitrile by the dehydration of adipamide is 99.5%. This process has the characteristics of few by-products, easy separation, low cost, non-toxicity, non-corrosion, etc. It is a new route for dehydroxylating 2-hydroxyadipamide to synthesize adipamide and adiponitrile, with dual environmental and economic values and broad development prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 1H NMR spectrum of 2-hydroxyadipamide as a raw material.

[0022] Figure 2 13C NMR spectrum of 2-hydroxyadipamide as a raw material.

[0023] Figure 3 1H NMR spectrum of the product adipamide.

[0024] Figure 4 13C NMR spectrum of the product adipamide. DETAILED DESCRIPTION OF THE INVENTION

[0025] The essential features and remarkable effects of the present invention can be embodied in the following embodiments, but they do not limit the present invention in any way. Those skilled in the art can make some non-essential improvements and adjustments based on the content of the present invention.

[0026] The present invention will be further described below through specific embodiments.

[0027] The dehydroxylation reaction formula of 2-hydroxyadipamide is as follows:

[0028]

[0029] Example 1:

[0030] 20 mg (0.125 mmol) of 2-hydroxyadipamide, 3 ml of 1,2-dimethoxyethane, and 15 mg of Mo 2 N are directly added into a closed autoclave, purged with nitrogen 5 times and then with hydrogen 5 times. Hydrogen is introduced to increase the pressure and temperature to 4 Mpa and 150 °C, and the mixture is stirred and reacted for 8 hours. After cooling to room temperature, liquid chromatography analysis shows that the conversion rate of 2-hydroxyadipamide is greater than 73.8%, and the yield of adipamide is greater than 50.5%. The structure of the substance is determined by NMR. From the Figure 1 and Figure 2 NMR spectra, it is shown that the raw material is determined to be 2-hydroxyadipamide. Figure 3 and Figure 4The successful synthesis of adipic amide was determined.

[0031] Example 2:

[0032] 20 mg (0.125 mmol) of 2-hydroxyadipic amide, 3 ml of tetrahydrofuran, and 20 mg of W 2 N were directly added to a sealed autoclave. The autoclave was purged with nitrogen 5 times and then with hydrogen 5 times. Hydrogen was introduced to increase the pressure and temperature to 4 Mpa and 160 °C, and the mixture was stirred and reacted for 8 hours. After cooling to room temperature, liquid chromatography analysis showed that the conversion rate of 2-hydroxyadipic amide was greater than 72.1%, and the yield of adipic amide was greater than 48.1%.

[0033] Example 3:

[0034] 20 mg (0.125 mmol) of 2-hydroxyadipic amide, 3 ml of 1,4-dioxane, and 25 mg of NiP were directly added to a sealed autoclave. The autoclave was purged with nitrogen 5 times and then with hydrogen 5 times. Hydrogen was introduced to increase the pressure and temperature to 3.5 Mpa and 160 °C, and the mixture was stirred and reacted for 8 hours. After cooling to room temperature, liquid chromatography analysis showed that the conversion rate of 2-hydroxyadipic amide was greater than 60.4%, and the yield of adipic amide was greater than 42.3%.

[0035] Example 4:

[0036] 20 mg (0.125 mmol) of 2-hydroxyadipic amide, 3 ml of tetrahydrofuran, and 40 mg of CoP were directly added to a sealed autoclave. The autoclave was purged with nitrogen 5 times and then with hydrogen 5 times. Hydrogen was introduced to increase the pressure and temperature to 5 Mpa and 180 °C, and the mixture was stirred and reacted for 8 hours. After cooling to room temperature, liquid chromatography analysis showed that the conversion rate of 2-hydroxyadipic amide was greater than 75.7%, and the yield of adipic amide was greater than 46.2%.

[0037] Example 5:

[0038] 20 mg (0.125 mmol) of 2-hydroxyadipic amide, 3 ml of tetrahydrofuran, and 30 mg of MoS 2 were directly added to a sealed autoclave. The autoclave was purged with nitrogen 5 times and then with hydrogen 5 times. Hydrogen was introduced to increase the pressure and temperature to 4 Mpa and 200 °C, and the mixture was stirred and reacted for 8 hours. After cooling to room temperature, liquid chromatography analysis showed that the conversion rate of 2-hydroxyadipic amide was greater than 56.5%, and the yield of adipic amide was greater than 46.2%.

[0039] Example 6:

[0040] 20 mg (0.125 mmol) of 2-hydroxyadipic amide, 3 ml of tetrahydrofuran, and 20 mg of Mo 2N was directly added into a closed autoclave, and replaced with nitrogen 5 times and then with hydrogen 5 times. Hydrogen was introduced to increase the pressure and temperature to 4 MPa and 200 °C, and the mixture was stirred and reacted for 8 hours. After cooling to room temperature, liquid chromatography analysis showed that the conversion rate of 2-hydroxyadipamide was greater than 57.6%, and the yield of adipamide was greater than 40.2%.

[0041] Example 7:

[0042] 20 mg (0.125 mmol) of 2-hydroxyadipamide, 3 ml of tetrahydrofuran, and 25 mg of MoS 2 were directly added into a closed autoclave, replaced with nitrogen 5 times and then with hydrogen 5 times. Hydrogen was introduced to increase the pressure and temperature to 2 MPa and 100 °C, and the mixture was stirred and reacted for 8 hours. After cooling to room temperature, liquid chromatography analysis showed that the conversion rate of 2-hydroxyadipamide was greater than 43.9%, and the yield of adipamide was greater than 16.2%.

[0043] Example 8:

[0044] 20 mg (0.125 mmol) of 2-hydroxyadipamide, 3 ml of tetrahydrofuran, and 35 mg of NiP were directly added into a closed autoclave, replaced with nitrogen 5 times and then with hydrogen 5 times. Hydrogen was introduced to increase the pressure and temperature to 6 MPa and 200 °C, and the mixture was stirred and reacted for 8 hours. After cooling to room temperature, liquid chromatography analysis showed that the conversion rate of 2-hydroxyadipamide was greater than 41.2%, and the yield of adipamide was greater than 15.4%.

[0045] Adipamide was used to synthesize adiponitrile by dehydration method:

[0046] The dehydration reaction equation of adipamide is:

[0047]

[0048] Example 9:

[0049] 30 mg (0.2 mmol) of adipamide obtained in Example 1, 10 ml of acetonitrile, and 30 mg of 5% Pd / ZSM-5 prepared by the impregnation method were heated to 100 °C and stirred and reacted for 8 hours. After cooling to room temperature, liquid chromatography analysis showed that the yield of adiponitrile was greater than 99.5%. The overall yield of the route from 2-hydroxyadipamide to adiponitrile was 47.9%.

[0050] Example 10:

[0051] 30 mg (0.2 mmol) of adipamide obtained in Example 1, 10 ml of acetonitrile, and 20 mg of 2% Pd / SBA-15 prepared by the impregnation method were heated to 120 °C and stirred and reacted for 8 hours. After cooling to room temperature, liquid chromatography analysis showed that the yield of adiponitrile was greater than 91.1%, and the overall yield of the route from 2-hydroxyadipamide to adiponitrile was 45.9%.

[0052] Example 11:

[0053] 30 mg (0.2 mmol) of adipamide obtained in Example 1, 10 ml of acetonitrile, and 25 mg of 3% Pd / TS-1 were prepared by the impregnation method. The temperature was raised to 150 °C and stirred for reaction for 8 hours. After cooling to room temperature, liquid chromatography analysis showed that the yield of adiponitrile was greater than 96.3%, and the overall yield of the route for preparing adiponitrile from 2-hydroxyadipamide was 48.6%.

[0054] Example 12:

[0055] 30 mg (0.2 mmol) of adipamide obtained in Example 1, 10 ml of acetonitrile, and 40 mg of 5% Pd / Nb 2 O 5 were prepared by the impregnation method. The temperature was raised to 150 °C and stirred for reaction for 8 hours. After cooling to room temperature, liquid chromatography analysis showed that the yield of adiponitrile was greater than 89.5%, and the overall yield of the route for preparing adiponitrile from 2-hydroxyadipamide was 45.2%.

[0056] Matters not covered by the present invention are well-known technologies.

Claims

1. A method for synthesizing adipamide by dehydroxylation using 2-hydroxyadipamide as a raw material, characterized in that the method comprises the following steps: Add 2-hydroxyadipamide, a solvent, and a catalyst into a reaction kettle, seal it, and introduce 3.5-6 Mpa of hydrogen. React at 100-250 °C for 1-30 h to obtain adipamide; The catalyst is NiP, CoP, MoP, Mo 3 P, Mo 2 N, W 2 N or MoS 2 ; The mass ratio of the catalyst to 2-hydroxyadipamide is 1:2-2:

1.

2. The method for synthesizing adipamide by dehydroxylation using 2-hydroxyadipamide as a raw material according to claim 1, characterized in that in the reaction system, the concentration of 2-hydroxyadipamide is 0.01-1 mol / L.

3. The method for synthesizing adipamide by dehydroxylation using 2-hydroxyadipamide as a raw material according to claim 1, characterized in that the solvent is tetrahydrofuran, N,N-dimethylformamide, 1,4-dioxane, dichloromethane or 1,2-dimethoxyethane.

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