A method for preparing bio-based long carbon chain dinitrile

Abstract

The present invention belongs to the field of bio-based materials, and relates to a method for preparing bio-based long carbon chain dinitriles. Bio-based long carbon chain dibasic acid and acetonitrile react under the action of diphenyl phosphate catalyst to obtain bio-based long carbon chain dinitriles. The present invention uses bio-based dibasic acid and acetonitrile as raw materials, and generates bio-based dinitriles and acetic acid through cyanide exchange under the action of organic phosphate catalyst. The present invention improves the mass transfer efficiency of microfluidic field technology reaction, shortens the reaction time, and can be produced continuously, which can greatly improve the production efficiency of long carbon chain dinitriles and has industrial application prospects. Compared with the prior art, the catalyst used in the present invention has high catalytic efficiency, small dosage, and low corrosion to reaction equipment.

Description

Technical Field

[0001] The invention belongs to the field of bio-based materials and relates to a method for preparing bio-based long carbon chain dinitriles. Background Art

[0002] Nitrile compounds are one of the important precursors for the synthesis of esters, amides, carboxylic acids and amines, and have important uses. Long-chain dinitrile compounds are key chemical intermediates for the synthesis of long-chain diamines and nylons. Long-chain dinitrile compounds play an important role in the organic synthesis of drugs, dyes, etc. They are also important intermediates for the production of new fibers, films, and plastic monomers, and have a large market demand.

[0003] Bio-based long-chain dinitriles have attracted widespread attention because their raw materials are derived from biomass, and they have the advantages of low carbon emissions and being more environmentally friendly. At present, the main synthesis method of bio-based dinitriles at home and abroad is to dehydrate bio-based dibasic acids with ammonia or with urea. This method has many by-products, low overall yield, and many intermediate products.

[0004] The prior art (Mlinaric-Majerski K, Margeta R, Veljkovic J, et al. A facileand efficient one-pot synthesis of nitriles from carboxylic acids[J].) discloses a method for synthesizing dinitriles using acid and acetonitrile as raw materials and concentrated sulfuric acid as a catalyst. The maximum yield of dinitriles is only 71%. In addition, the method uses a large amount of sulfuric acid, which is 10 to 20 times the molar amount of the dibasic acid. The sulfuric acid after the reaction is difficult to recover, which pollutes the environment. Sulfuric acid is easy to corrode the reactor, is environmentally unfriendly, and has low safety.

[0005] Therefore, there is an urgent need to develop a new method for synthesizing bio-based dinitriles with low by-products, low intermediates, high yield and environmental protection. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a new method for efficiently preparing bio-based dinitriles in view of the shortcomings of the prior art; in particular, a new method for efficiently preparing bio-based dinitriles using a microfluidic field reactor is provided to improve the mass transfer efficiency of heterogeneous reactions, reduce the generation of by-products, realize continuous production, and greatly improve the production efficiency of bio-based dinitriles.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0008] The invention discloses a method for preparing a bio-based long carbon chain dinitrile, wherein a bio-based long carbon chain dibasic acid and acetonitrile react under the action of a catalyst to obtain a bio-based long carbon chain dinitrile;

[0009] The catalyst has a structure shown in Formula I:

[0010] ;

[0011] in,

[0012] R 1 , R 2 independently selected from alkyl, halogen or aryl;

[0013] m is selected from 0 to 5; n is selected from 0 to 5.

[0014] In some embodiments, the bio-based long carbon chain dicarboxylic acid is selected from aliphatic dicarboxylic acids having 6 to 36 carbon atoms or alicyclic dicarboxylic acids having 6 to 36 carbon atoms.

[0015] In some embodiments, preferably, the bio-based long carbon chain dibasic acid is selected from adipic acid, sebacic acid or hydrogenated dimer acid.

[0016] In some embodiments, m is selected from 0; n is selected from 0.

[0017] In some embodiments, the molar ratio of the acetonitrile to the bio-based long carbon chain dibasic acid is 10-40:1; the molar ratio of the bio-based long carbon chain dibasic acid to the catalyst is 1:0.01-0.1.

[0018] In some embodiments, preferably, the molar ratio of the bio-based long carbon chain dibasic acid to the catalyst is 1:0.01-0.05, and more preferably 1:0.01.

[0019] In some embodiments, the reaction temperature is 150-240° C. and the reaction pressure is 1-5 Mpa.

[0020] In some embodiments, preferably, the reaction temperature is 180-220° C., more preferably 200° C., and the reaction pressure is 1-3 Mpa, more preferably 2 Mpa.

[0021] In some embodiments, a conventional reactor or a microfluidic reaction device is used to prepare bio-based long carbon chain dinitriles.

[0022] In some embodiments, preferably, the preparation of bio-based long carbon chain dinitriles using a microfluidic reaction device comprises the following steps:

[0023] The bio-based long carbon chain dibasic acid, acetonitrile and a catalyst are mixed to obtain a reaction solution; the reaction solution is pumped into a microfluidic reactor of a microfluidic reaction device for reaction to obtain the bio-based long carbon chain dinitrile.

[0024] In some embodiments, the reaction residence time in the microfluidic field reactor is 20 to 60 minutes.

[0025] In some embodiments, preferably, the reaction residence time in the microfluidic field reactor is 20 to 40 minutes, and more preferably 30 minutes.

[0026] In some embodiments, the reaction solution is pumped into the microfluidic reaction device at a flow rate of 0.1-0.4 mL / min, preferably 0.2 mL / min.

[0027] In some embodiments, the microfluidic field reaction device includes a connecting pipe, an injection pump, a microfluidic field reactor, a back pressure valve and a receiving device; wherein the injection pump, the microfluidic field reactor and the receiving device are connected in series in sequence through a connecting pipe; a back pressure valve is provided on the microfluidic field reactor to control the internal pressure of the microfluidic field reactor.

[0028] Wherein, the inner diameter of the connecting pipe is 0.5~2.0 mm, preferably 1.0 mm.

[0029] Wherein, the injection pump is a high-pressure plunger pump.

[0030] Wherein, the microfluidic field reactor has a pore structure, and the pore material is stainless steel or titanium alloy.

[0031] Wherein, the inner diameter of the pores of the microfluidic field reactor is 0.5-2.0 mm, preferably 1.0 mm.

[0032] Wherein, the volume of the microfluidic field reactor is 2-10 mL, preferably 6 mL.

[0033] Among them, separation and purification are carried out after the reaction is completed, and the by-products mainly include acetic acid and other impurities.

[0034] Beneficial effects:

[0035] (1) The present invention uses bio-based dibasic acid and acetonitrile as raw materials, and generates bio-based dinitriles and acetic acid through cyanide exchange under the action of an organic phosphate catalyst. The present invention improves the mass transfer efficiency of the microfluidic field reaction, shortens the reaction time, and can be produced continuously, which can greatly improve the production efficiency of long-chain dinitriles and has industrial application prospects.

[0036] (2) Compared with the prior art, the catalyst used in the present invention has high catalytic efficiency, small dosage, low corrosiveness to reaction equipment, and is environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0038] Figure 1 For sebacate 1 H NMR spectrum.

[0039] Figure 2 For adiponitrile 1 H NMR spectrum.

[0040] Figure 3 For hydrogenated dipolynitrile 1 H NMR spectrum.

[0041] Figure 4 Schematic diagram of the process of the microfluidic reaction device used in the embodiment of the present invention. DETAILED DESCRIPTION

[0042] The present invention can be better understood according to the following examples. However, it is easy for those skilled in the art to understand that the contents described in the examples are only used to illustrate the present invention, and should not and will not limit the present invention described in detail in the claims.

[0043] The experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0044] 1. All chemical structural formulas in the present invention are drawn using the software KingDraw.

[0045] 2. The specific preparation process of the bio-based long carbon chain dinitriles in the embodiment of the present invention is as follows:

[0046] The catalyst and the dibasic acid are mixed with acetonitrile to obtain a mixture; the mixture is pumped into a microfluidic reactor of a microfluidic reactor device by a high-pressure injection pump for reaction, and the reaction temperature and pressure are adjusted to achieve sufficient reaction to obtain the product.

[0047] Wherein, the above-mentioned microfluidic field reaction device includes a connecting pipe, an injection pump, a microfluidic field reactor and a receiving device; wherein the injection pump, the microfluidic field reactor and the receiving device are connected in series in sequence through a connecting pipe; the microfluidic field reactor is provided with a back pressure valve to control the internal pressure of the microfluidic field reactor; the injection pump pumps the reaction raw materials (a mixture of dibasic acid, catalyst and acetonitrile) into the microfluidic field reactor of the microfluidic field reaction device for reaction. Wherein, the inner diameter of the connecting pipe is 1.0 mm; the injection pump is a high-pressure plunger pump; the microfluidic field reactor has a pore structure, and the pore material is stainless steel; the inner diameter of the pore of the microfluidic field reactor is 1.0 mm; the volume of the microfluidic field reactor is 6 mL. See the specific flow chart. Figure 4 .

[0048] Example 1

[0049]

[0050] Sebacic acid (2.02 g, 10 mmol), diphenyl phosphate (25 mg, 0.1 mmol), and 15 mL of acetonitrile were added to a round-bottom flask, and a magnetic stirrer was added for 10 minutes to obtain a clear reaction solution.

[0051] The reaction liquid was pumped into the microfluidic reactor of the microfluidic reaction device by a high-pressure plunger pump for reaction. The pressure of the reaction system was controlled to be 2 Mpa by a back pressure valve. The flow rate was adjusted to 0.2 mL / min by a high-pressure plunger pump. The reaction temperature was 200°C. The volume of the microfluidic reactor was 6 mL, and the reaction residence time was 0.5 h. The reaction liquid flowing out of the microfluidic reactor was distilled, separated and purified to obtain light yellow liquid sebacononitrile, 1.5 g, with a yield of 91.5%.

[0052] Example 1 Sebaconitrile prepared 1 H NMR spectrum Figure 1 The specific NMR and mass spectrometry data are as follows: 1 HNMR (400 MHz, Chloroform- d ) δ 2.28 (t, J = 7.1 Hz, 4H), 1.66 – 1.55 (m, 4H),1.46 – 1.35 (m, 4H), 1.32 – 1.24 (m, 4H). HRMS (ESI) m / z calcd. for C 10 H 17 N2[M+H] + 165.1387, found 165.1388.

[0053] Example 2

[0054]

[0055] A magnetic stirrer, sebacic acid (2.02 g, 10 mmol), and diphenyl phosphate (25 mg, 0.1 mmol) were added to the high-pressure reactor. After nitrogen replacement, 15 mL of acetonitrile was added, and the reaction temperature was increased to 200°C. After reacting for 8 h, the temperature of the reaction liquid was lowered to room temperature. The reaction liquid was distilled, separated and purified to obtain a light yellow liquid sebacic acid (1.03 g) with a yield of 63.0%.

[0056] Comparative Example 1

[0057] Sebacic acid (2.02 g, 10 mmol) and 1.2 g composite catalyst (n(ZnO)∶n(Al2O3)=2∶1) were placed in a 250 mL reactor, 20 mL ammonia water was added, nitrogen was introduced for replacement 5 times, and then ammonia was introduced. After saturation with ammonia, the temperature began to rise. The reactor was heated from 140℃ to 210℃ in the low temperature zone, and ammonia was intermittently passed to control the pressure in the reactor to 0.4 MPa. The temperature was programmed to rise, and attention was paid to the reaction temperature control. The reaction was carried out in the low temperature zone for 8 h; the temperature was continued to rise, and the reaction temperature was controlled to rise from 210℃ to 265℃ in the high temperature zone, and ammonia was intermittently passed to control the pressure in the reactor to 0.15 MPa, and the reaction was carried out in the high temperature zone for 5 h. After the reaction was completed, the crude product and the organic matter in the receiver of the reflux device were distilled under reduced pressure to obtain a light yellow oily liquid sebaconitrile, 1.01 g, with a yield of 62%.

[0058] Example 3

[0059]

[0060] Adipic acid (1.46 g, 10 mmol), diphenyl phosphate (25 mg, 0.1 mmol), and 15 mL of acetonitrile were added to a round-bottom flask, and a magnetic stirrer was added for 10 minutes to obtain a clear reaction solution.

[0061] The reaction liquid was pumped into the microfluidic reactor of the microfluidic reaction device by a high-pressure plunger pump for reaction. The pressure of the reaction system was controlled to be 2 Mpa by a back pressure valve. The flow rate was adjusted to 0.2 mL / min by a high-pressure plunger pump. The reaction temperature was 200°C. The volume of the microfluidic reactor was 6 mL, and the reaction residence time was 0.5 h. The reaction liquid flowing out of the microfluidic reactor was extracted with ether, the by-product acetic acid was washed away with sodium bicarbonate aqueous solution, and concentrated by a rotary evaporator to obtain a colorless liquid of adiponitrile, 0.9 g, with a yield of 83.3%.

[0062] Example 3: Adiponitrile obtained 1 H NMR spectrum Figure 2 The specific NMR and mass spectrometry data are as follows: 1 HNMR (400 MHz, Chloroform- d ) δ 2.38 (m, 4H), 1.79 (m, 4H). HRMS (ESI) m / zcalcd. for C6H9N2[M + H] + 109.0761, found 109.0760.

[0063] Example 4

[0064]

[0065] Hydrogenated dimer acid (5.64 g, 10 mmol), diphenyl phosphate (25 mg, 0.1 mmol), and 20 mL of acetonitrile were added to a round-bottom flask, and a magnetic stirrer was added for 10 minutes to obtain a clear reaction solution.

[0066] The reaction liquid was pumped into the microfluidic reactor of the microfluidic reaction device by a high-pressure plunger pump for reaction. The pressure of the reaction system was controlled to be 2 Mpa by a back pressure valve, the flow rate was adjusted to 0.2 mL / min by a high-pressure plunger pump, and the reaction temperature was 200°C. The volume of the microfluidic reactor was 6 mL, and the reaction residence time was 0.5 h. The reaction liquid flowing out of the microfluidic reactor was extracted with ether, the by-product acetic acid was washed away with sodium bicarbonate aqueous solution, and concentrated by a rotary evaporator to obtain a light yellow liquid hydrogenated dipolynitrile, 5.2 g, with a yield of 98.9%.

[0067] Example 4 Hydrogenated dipolynitrile 1 H NMR spectrum Figure 3 The specific NMR and mass spectrometry data are as follows: 1 HNMR (400 MHz, Chloroform- d ) δ 2.28 (t, J = 7.2 Hz, 4H), 1.51 (d, J = 18.1 Hz,7H), 1.21 (d, J = 15.4 Hz, 47H), 0.90 – 0.71 (m, 8H). HRMS (ESI) m / z calcd. forC 36 H 67 N2[M + H] + 527.5299, found 527.5296.

[0068] The present invention provides a method and idea for preparing a bio-based long carbon chain dinitriles. There are many methods and approaches to realize the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention. All components not specified in this embodiment can be realized by existing technologies.

Claims

1. A method for preparing a bio-based long carbon chain dinitrile, characterized in that: The bio-based long carbon chain dibasic acid and acetonitrile react under the action of a catalyst to obtain the bio-based long carbon chain dinitrile; The catalyst is diphenyl phosphate; The bio-based long carbon chain dinitriles were prepared by using a microfluidic reaction device; The preparation of bio-based long carbon chain dinitriles using a microfluidic reaction device comprises the following steps: The bio-based long carbon chain dibasic acid, acetonitrile and a catalyst are mixed to obtain a reaction solution; the reaction solution is pumped into a microfluidic reactor of a microfluidic reactor device for reaction to obtain the bio-based long carbon chain dinitrile; The reaction temperature is 180-220°C and the reaction pressure is 1-5 Mpa; The bio-based long carbon chain dicarboxylic acid is selected from aliphatic dicarboxylic acids having 6 to 36 carbon atoms or alicyclic dicarboxylic acids having 6 to 36 carbon atoms.

2. The method according to claim 1, characterized in that The bio-based long carbon chain dibasic acid is selected from adipic acid, sebacic acid or hydrogenated dimer acid.

3. The method according to claim 1, characterized in that The molar ratio of the acetonitrile to the bio-based long carbon chain dibasic acid is 10-40:1; the molar ratio of the bio-based long carbon chain dibasic acid to the catalyst is 1:0.01-0.

1.

4. The method according to claim 1, characterized in that The reaction residence time in the microfluidic field reactor is 20 to 60 minutes.

5. The method according to claim 1, characterized in that The microfluidic field reaction device comprises a connecting pipe, an injection pump, a microfluidic field reactor, a back pressure valve and a receiving device; wherein the injection pump, the microfluidic field reactor and the receiving device are connected in series in sequence through the connecting pipe; and a back pressure valve is provided on the microfluidic field reactor to control the internal pressure of the microfluidic field reactor.

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