Synthesis method of 1-amino-2-cyano-1-cyclopentene

Abstract

The invention provides a synthesis method of 1-amino-2-cyano-1-cyclopentene, which comprises the following steps: 1, mixing an ionic liquid and a super-strong organic alkali in a protective gas atmosphere, heating, stirring, uniformly mixing and dissolving to obtain a material A; the ionic liquid is selected from at least one of [BMIM] PF6, [BMIM] BF4, [BMIM] NTf2, [BMIM] OTf and [BMIM] OAc; 2, adiponitrile is dropwise added into the material A under stirring for a reaction, and a material B rich in 1-amino-2-cyano-1-cyclopentene is obtained; 3, cooling and crystallizing the material B, and carrying out pressure filtration to obtain an ACCP crude product; and 4, recrystallizing and refining the obtained ACCP crude product to obtain a pure product. The method provided by the invention has the advantages of simplicity, high efficiency, sustainable production, low cost, low content of generated three wastes, mild reaction conditions and suitability for industrial production.

Description

Technical Field

[0001] The invention belongs to the technical field of compound synthesis, and specifically relates to a method for synthesizing 1-amino-2-cyano-1-cyclopentene (ACCP). Background Art

[0002] Amino-2-cyano-1-cyclopentene (ACCP) contains multiple functional groups such as cyano, amino, and double bonds in the ring. It has active chemical properties and a wide range of uses. It can be used to synthesize cyclopentanone, a raw material for flavors, and 2-aminocyclopentanemethylamine, a pharmaceutical intermediate.

[0003] At present, the synthesis of 1-amino-2-cyano-1-cyclopentene has been reported in the literature. There are mainly the following methods for preparing ACCP as the main product.

[0004] The gas phase ammonolysis method (CN109608360B) is used, with dimethyl adipate and hot ammonia as raw materials, and reacted at 300-400 °C for 10 h under the catalysis of solid acids such as aluminum oxide and iron oxide, and the mixed material is condensed and collected. The obtained material is then distilled under reduced pressure, cooled and crystallized, and finally recrystallized with a benzene solvent to obtain pure ACCP.

[0005] A continuous fixed bed process (CN115197094A) is used, with adiponitrile as the raw material, and a fixed bed reactor is used for continuous cyclization at 195-205 °C under the catalysis of a supported catalyst modified with di(trimethylsilyl)aminocesium. However, the preparation process of the supported catalyst is relatively cumbersome and requires two calcinations. The first time, the acidic molecular sieve is modified with di(trimethylsilyl)aminocesium, and then calcined at 300-400 °C for 6-8 h after equal volume impregnation and drying. The second time, the di(trimethylsilyl)aminocesium modified molecular sieve is impregnated in an aqueous solution of a soluble metal nitrate, dried, and calcined at 400-500 °C for 4-6 h.

[0006] The two-liquid phase microemulsion condensation method (CN116253664A) is adopted. With adiponitrile as the raw material, adiponitrile is mixed with a benzene dispersion, and then an alkaline condensation initiator and an emulsifier sodium hexadecylbenzene sulfonate are added in sequence to prepare a microemulsion. After the microemulsion enters the spray fluidized bed, it is fluidized in a nitrogen atmosphere at a temperature of 120-200 °C and finally vacuum dried to obtain the pure ACCP product.

[0007] In addition, there is an infrared radiation method (CN116003295A), which uses tert-butyl alcohol and adiponitrile as raw materials, and uses a nano-infrared energy-saving electric heating ring to heat to 40~80 ℃. At the same time, infrared radiation is used to excite tert-butyl alcohol to generate tert-butyloxy free radicals, promote the cyclization reaction of adiponitrile, and finally separate the product by rotary evaporation. The overall yield of ACCP in this reaction is low, and the post-processing method is too simple, making it difficult to remove unreacted adiponitrile.

[0008] It can be seen that the current methods for preparing 1-amino-2-cyano-1-cyclopentene have harsh preparation conditions, either directly or indirectly involving high temperature reactions, or requiring the use of complex equipment, or requiring the use of highly toxic benzene as a solvent. Therefore, it is of great significance to provide a mild, simple and efficient preparation method for ACCP. Summary of the invention

[0009] The invention provides a method for synthesizing 1-amino-2-cyano-1-cyclopentene. The preparation process has mild reaction, simple steps, high reaction efficiency, high product yield, high purity, less three wastes, effectively solves the problem of solvent recovery, and greatly reduces production costs.

[0010] To solve the above problems, the technical solution adopted by the present invention is: a method for synthesizing 1-amino-2-cyano-1-cyclopentene, comprising the following steps: 1. In a protective gas atmosphere, the ionic liquid is mixed with a super strong organic base, heated and stirred, mixed and dissolved to obtain material A; the ionic liquid is selected from [BMIM] PF 6 , [BMIM]BF 4 , [BMIM]NTf 2 , [BMIM]OTf, [BMIM]OAc; 2. adding adiponitrile dropwise into the stirred material A to react, thereby obtaining a material B rich in 1-amino-2-cyano-1-cyclopentene; 3. Cooling and crystallizing material B, and filtering under pressure to obtain crude ACCP; 4. The obtained crude ACCP is purified by recrystallization to obtain a pure product.

[0011] The above preparation reaction equation is shown as follows: , Where X - Selected from PF 6 - , BF 4 - NTf 2 - ,OTf - ,OAc - At least one of the following, Base is a super strong organic base.

[0012] Furthermore, in the aforementioned method for synthesizing 1-amino-2-cyano-1-cyclopentene, the filtrate obtained by pressure filtration in the third step is recycled for the next round of reaction.

[0013] Furthermore, in the aforementioned method for synthesizing 1-amino-2-cyano-1-cyclopentene, in the first step, the super strong organic base is at least one of potassium tert-butoxide, sodium tert-butoxide, lithium bis(trimethylsilyl)amide, n-butyl lithium, lithium diisopropylamide, potassium methoxide, and potassium ethoxide.

[0014] Furthermore, in the aforementioned method for synthesizing 1-amino-2-cyano-1-cyclopentene, the ratio of the volume of the ionic liquid to the molar amount of the super strong organic base is 0.5~5.0:1, wherein the volume unit of the ionic liquid is liter and the molar amount unit of the super strong organic base is mole.

[0015] Furthermore, in the aforementioned method for synthesizing 1-amino-2-cyano-1-cyclopentene, in the first step, the protective gas is nitrogen or argon.

[0016] Furthermore, in the aforementioned method for synthesizing 1-amino-2-cyano-1-cyclopentene, in the first step, the heating and stirring time is 0.4 to 2.0 hours, and the temperature is 60 to 80°C.

[0017] Furthermore, in the aforementioned method for synthesizing 1-amino-2-cyano-1-cyclopentene, in the second step, the adiponitrile dropping speed is 1-4 mL / min, and the temperature during the dropping is controlled at 60-80 °C.

[0018] Furthermore, in the aforementioned method for synthesizing 1-amino-2-cyano-1-cyclopentene, in the second step, the molar ratio of adiponitrile to the super strong organic base is 0.8 to 1.7.

[0019] Furthermore, in the aforementioned method for synthesizing 1-amino-2-cyano-1-cyclopentene, in the third step, the cooling and crystallization temperature is controlled at -10°C to 5°C.

[0020] Furthermore, in the aforementioned method for synthesizing 1-amino-2-cyano-1-cyclopentene, in the third step, the pressure during pressurized filtration is 0.3-0.45 MPa under a protective gas atmosphere.

[0021] Further, in the aforementioned method for synthesizing 1-amino-2-cyano-1-cyclopentene, in the fourth step, the step of recrystallization and purification comprises: dissolving the crude ACCP product in an organic solvent, heating and evaporating to concentrate, cooling and crystallizing, filtering, and vacuum drying. The organic solvent can be selected from one of toluene, xylene, and 1,2-dichloroethane.

[0022] The advantages of the present invention application are: under the protective gas atmosphere, the mixed system of ionic liquid and super organic base is constructed, the reaction is mild, and the product is separated from the mixed system of ionic liquid and super organic base by pressure filtration, and the product yield is high and the purity is high. The separated ionic liquid and super organic base can be back-reacted, and the yield and purity of the back-reaction do not change much. Therefore, the whole preparation process has mild conditions, simple steps, efficient reaction, convenient post-processing, high product yield and high purity, and more importantly, less three wastes, effectively solves the problem of solvent recovery, greatly reduces production costs, effectively avoids pollution to the environment, and is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the gas chromatogram of 1-amino-2-cyano-1-cyclopentene prepared in Example 1.

[0024] Figure 2 This is the carbon NMR spectrum of 1-amino-2-cyano-1-cyclopentene prepared in Example 1. DETAILED DESCRIPTION

[0025] The synthesis method of 1-amino-2-cyano-1-cyclopentene described in the present invention is further described in detail below in conjunction with preferred embodiments.

[0026] Example 1: Under nitrogen protection, 58.9 g of potassium tert-butoxide was added to a 1000 mL three-necked flask, followed by 560 mL of 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM] + PF 6 -), the two were stirred at 60 ° C for 0.5 h to obtain material A. At this temperature, 54.0 g of adiponitrile was slowly added to material A using a constant pressure dropping funnel at a dropping speed of 1 mL / min, and the reaction was kept warm for 4 h to obtain material B rich in 1-amino-2-cyano-1-cyclopentene (ACCP). Material B was cooled to 5 ° C and allowed to stand for 3 h. After crystals were precipitated, the pressure was controlled at 0.45 MPa for pressure filtration to obtain 52.8 g of ACCP filter cake with a purity of 96.1%, and 554 mL of filtrate was recovered. The obtained ACCP filter cake was dissolved in 200 mL of 1, 2-dichloroethane, heated and evaporated, and then cooled to 5 ° C and allowed to stand for 3 h to crystallize. The solid was filtered and vacuum dried to obtain 48.8 g of ACCP fine product with a yield of 90.4% and a purity of 100%.

[0027] The recovered filtrate was placed in a 1000 mL three-necked flask, and 54.0 g of adiponitrile was slowly added dropwise at 60 °C at a rate of 1 mL / min. The reaction was kept warm for 4 h to obtain material B rich in 1-amino-2-cyano-1-cyclopentene (ACCP). Material B was cooled to -10 °C and allowed to stand for 3 h. After crystals were precipitated, the pressure was controlled at 0.45 MPa for pressure filtration to obtain 52.6 g of ACCP filter cake with a purity of 96.1%, and 549 mL of secondary recovered filtrate. The obtained ACCP filter cake was dissolved in 200 mL of 1, 2-dichloroethane, heated and evaporated, and then cooled to 5 °C and allowed to stand for 3 h for crystallization. The solid was filtered and vacuum dried to obtain 48.7 g of ACCP fine product with a yield of 90.2% and a purity of 100%.

[0028] The gas chromatogram of the product 1-amino-2-cyano-1-cyclopentene (ACCP) is shown in Figure 1 As shown, the carbon NMR spectrum is shown in Figure 2 As shown, the nuclear magnetic resonance signal characterization, 1 H NMR (600 MHz, DMSO- d 6 ) δ 6.38 (s, 2H), 2.39(t, J = 7.1 Hz, 2H), 2.34 (t, J = 7.7 Hz, 2H), 1.78 (p, J = 7.5 Hz, 2H). 13 CNMR (151 MHz, DMSO- d 6 ) δ 164.51, 120.42, 68.50, 34.31, 31.35, 22.13.

[0029] Example 2: Under nitrogen protection, 58.9 g of potassium tert-butoxide was added to a 1000 mL three-necked flask, followed by 560 mL of 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM] + BF 4 - ), the two were stirred at 60 ° C for 0.5 h to obtain material A. At this temperature, 54.0 g of adiponitrile was slowly added to material A using a constant pressure dropping funnel at a dropping speed of 2 mL / min, and the reaction was kept warm for 4 h to obtain material B rich in 1-amino-2-cyano-1-cyclopentene (ACCP). Material B was cooled to 5 ° C and allowed to stand for 3 h. After crystals were precipitated, the pressure was controlled at 0.45 MPa for pressure filtration to obtain 52.6 g of ACCP filter cake with a purity of 95.9%, and 554 mL of filtrate was recovered. The obtained ACCP filter cake was dissolved in 200 mL of 1, 2-dichloroethane, heated and evaporated, and then cooled to 5 ° C and allowed to stand for 3 h to crystallize. The solid was filtered and vacuum dried to obtain 48.1 g of ACCP fine product with a yield of 88.9% and a purity of 99.8%.

[0030] The recovered filtrate was placed in a 1000 mL three-necked flask, and 54.0 g of adiponitrile was slowly added dropwise at 60 °C at a rate of 2 mL / min. The reaction was kept warm for 4 h to obtain material B rich in 1-amino-2-cyano-1-cyclopentene (ACCP). Material B was cooled to 5 °C and allowed to stand for 3 h. After crystals were precipitated, the pressure was controlled at 0.45 MPa for pressure filtration to obtain 52.7 g of ACCP filter cake with a purity of 95.1%, and 549 mL of secondary filtrate was recovered. The obtained ACCP filter cake was dissolved in 200 mL of 1, 2-dichloroethane, heated and evaporated, and then cooled to 5 °C and allowed to stand for 3 h for crystallization. The solid was filtered and vacuum dried to obtain 48.0 g of ACCP fine product with a yield of 88.7% and a purity of 99.8%.

[0031] In this example, 1-amino-2-cyano-1-cyclopentene (ACCP) was characterized by nuclear magnetic resonance. 1 H NMR (600MHz, DMSO- d 6 ) δ 6.38 (s, 2H), 2.39 (t, J = 7.1 Hz, 2H), 2.34 (t, J = 7.7 Hz,2H), 1.78 (p, J = 7.5 Hz, 2H). 13 C NMR (151 MHz, DMSO- d 6) δ 164.51, 120.42, 68.50, 34.31, 31.35, 22.13.

[0032] Example 3: Under argon protection, 58.9 g of potassium tert-butoxide was added to a 1000 mL three-necked flask, followed by 560 mL of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIM] + Ntf 2 - ), the two were stirred at 60 ° C for 0.5 h to obtain material A. At this temperature, 54.0 g of adiponitrile was slowly added to material A using a constant pressure dropping funnel at a dropping rate of 2 mL / min, and the reaction was kept warm for 4 h to obtain material B rich in 1-amino-2-cyano-1-cyclopentene (ACCP). Material B was cooled to 5 ° C and allowed to stand for 3 h. After crystals were precipitated, the pressure was controlled at 0.4 MPa for pressure filtration to obtain 52.3 g of ACCP filter cake with a purity of 94.3%, and 543 mL of filtrate was recovered. The obtained ACCP filter cake was dissolved in 200 mL of 1, 2-dichloroethane, heated and evaporated, and then cooled to 5 ° C and allowed to stand for 3 h to crystallize. The solid was filtered and vacuum dried to obtain 46.9 g of ACCP fine product with a yield of 86.8% and a purity of 99.9%.

[0033] The recovered filtrate was placed in a 1000 mL three-necked flask, and 54.0 g of adiponitrile was slowly added at 60 °C at a rate of 2 mL / min. The reaction was kept warm for 4 h to obtain material B rich in 1-amino-2-cyano-1-cyclopentene (ACCP). Material B was cooled to 5 °C and allowed to stand for 3 h. After crystals were precipitated, the pressure was controlled at 0.4 MPa for pressure filtration to obtain 51.8 g of ACCP filter cake with a purity of 94.2%, and 527 mL of secondary filtrate was recovered. The obtained ACCP filter cake was dissolved in 200 mL of 1, 2-dichloroethane, heated and evaporated, and then cooled to 5 °C and allowed to stand for 3 h for crystallization. The solid was filtered and vacuum dried to obtain 46.8 g of ACCP fine product with a yield of 86.5% and a purity of 99.8%.

[0034] Example 4: Under nitrogen protection, 58.9 g of potassium tert-butoxide was added to a 1000 mL three-necked flask, followed by 560 mL of 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([BMIM] + OTf -), the two were stirred at 60 ° C for 0.5 h to obtain material A. At this temperature, 54.0 g of adiponitrile was slowly added to material A using a constant pressure dropping funnel at a dropping speed of 2 mL / min, and the reaction was kept warm for 4 h to obtain material B rich in 1-amino-2-cyano-1-cyclopentene (ACCP). Material B was cooled to 5 ° C and allowed to stand for 3 h. After crystals were precipitated, the pressure was controlled at 0.3 MPa for pressure filtration to obtain 53.1 g of ACCP filter cake with a purity of 94.2%, and 532 mL of filtrate was recovered. The obtained ACCP filter cake was dissolved in 200 mL of toluene, heated and evaporated, concentrated, cooled to 5 ° C and allowed to stand for 3 h for crystallization, the solid was filtered and vacuum dried to obtain 47.7 g of ACCP fine product with a yield of 88.2% and a purity of 99.8%.

[0035] The recovered filtrate was placed in a 1000 mL three-necked flask, and 54.0 g of adiponitrile was slowly added dropwise at 60 °C at a rate of 2 mL / min. The reaction was kept warm for 4 h to obtain material B rich in 1-amino-2-cyano-1-cyclopentene (ACCP). Material B was cooled to 5 °C and allowed to stand for 3 h. After crystals were precipitated, the pressure was controlled at 0.3 MPa for pressure filtration to obtain 52.2 g of ACCP filter cake with a purity of 94.1%, and 527 mL of secondary recovered filtrate. The obtained ACCP filter cake was dissolved in 200 mL of toluene, heated and evaporated, concentrated, cooled to 5 °C, allowed to stand for 3 h for crystallization, and the solid was filtered and vacuum dried to obtain 47.4 g of ACCP fine product with a yield of 87.6% and a purity of 99.8%.

[0036] Example 5: Under nitrogen protection, 58.9 g of potassium tert-butoxide was added to a 1000 mL three-necked flask, followed by 560 mL of ([BMIM] + OAc - ), the two were stirred at 60 ° C for 0.5 h to obtain material A. At this temperature, 54.0 g of adiponitrile was slowly added to material A using a constant pressure dropping funnel at a dropping speed of 2 mL / min, and the reaction was kept warm for 4 h to obtain material B rich in 1-amino-2-cyano-1-cyclopentene (ACCP). Material B was cooled to 5 ° C and allowed to stand for 3 h. After crystals were precipitated, the pressure was controlled at 0.3 MPa for pressure filtration to obtain 53.6 g of ACCP filter cake with a purity of 92.8%, and 538 mL of filtrate was recovered. The obtained ACCP filter cake was dissolved in 200 mL of xylene, heated and evaporated, concentrated, cooled to 5 ° C, allowed to stand for 3 h for crystallization, the solid was filtered and vacuum dried to obtain 47.9 g of ACCP fine product with a yield of 88.5% and a purity of 99.8%.

[0037] The recovered filtrate was placed in a 1000 mL three-necked flask, and 54.0 g of adiponitrile was slowly added dropwise at 60 °C at a rate of 2 mL / min. The reaction was kept warm for 4 h to obtain material B rich in 1-amino-2-cyano-1-cyclopentene (ACCP). Material B was cooled to 5 °C and allowed to stand for 3 h. After crystals were precipitated, the pressure was controlled at 0.3 MPa for pressure filtration to obtain 52.7 g of ACCP filter cake with a purity of 93.8%, and 416 mL of secondary recovered filtrate. The obtained ACCP filter cake was dissolved in 200 mL of xylene, heated and evaporated, concentrated, cooled to 5 °C, allowed to stand for 3 h for crystallization, and the solid was filtered and vacuum dried to obtain 47.8 g of ACCP fine product with a yield of 88.3% and a purity of 99.8%.

[0038] Example 6: Under nitrogen protection, 20.6 g of potassium methoxide was added to a 1000 mL three-necked flask, followed by 560 mL of 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM] + PF 6 - ), the two were stirred at 80 ° C for 1.0 h to obtain material A. At this temperature, 54.0 g of adiponitrile was slowly added to material A using a constant pressure dropping funnel at a dropping speed of 1 mL / min, and the reaction was kept warm for 4 h to obtain material B rich in 1-amino-2-cyano-1-cyclopentene (ACCP). Material B was cooled to 5 ° C and allowed to stand for 3 h. After crystals were precipitated, the pressure was controlled at 0.3 MPa for pressure filtration to obtain 50.1 g of ACCP filter cake with a purity of 95.7%, and 549 mL of filtrate was recovered. The obtained ACCP filter cake was dissolved in 200 mL of 1, 2-dichloroethane, heated and evaporated, and then cooled to 5 ° C and allowed to stand for 3 h to crystallize. The solid was filtered and vacuum dried to obtain 45.4 g of ACCP fine product with a yield of 83.8% and a purity of 99.7%.

[0039] The recovered filtrate was placed in a 1000 mL three-necked flask, and 54.0 g of adiponitrile was slowly added dropwise at 60 °C at a rate of 1 mL / min. The reaction was kept warm for 4 h to obtain material B rich in 1-amino-2-cyano-1-cyclopentene (ACCP). Material B was cooled to 5 °C and allowed to stand for 3 h. After crystals were precipitated, the pressure was controlled at 0.3 MPa for pressure filtration to obtain 49.8 g of ACCP filter cake with a purity of 95.4%, and 538 mL of secondary filtrate was recovered. The obtained ACCP filter cake was dissolved in 200 mL of 1, 2-dichloroethane, heated and evaporated, and then cooled to 5 °C and allowed to stand for 3 h for crystallization. The solid was filtered and vacuum dried to obtain 45.1 g of ACCP fine product with a yield of 83.3% and a purity of 99.7%.

[0040] Example 7: Under nitrogen protection, 52.6 g of potassium ethoxide was added to a 1000 mL three-necked flask, followed by 560 mL of 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM] + PF 6 - ), the two were stirred at 80 ° C for 1.0 h to obtain material A. At this temperature, 54.0 g of adiponitrile was slowly added to material A using a constant pressure dropping funnel at a dropping speed of 2 mL / min, and the reaction was kept warm for 4 h to obtain material B rich in 1-amino-2-cyano-1-cyclopentene (ACCP). Material B was cooled to 5 ° C and allowed to stand for 3 h. After crystals were precipitated, the pressure was controlled at 0.3 MPa for pressure filtration to obtain 50.4 g of ACCP filter cake with a purity of 95.8%, and 543 mL of filtrate was recovered. The obtained ACCP filter cake was dissolved in 200 mL of 1, 2-dichloroethane, heated and evaporated, and then cooled to 5 ° C and allowed to stand for 3 h to crystallize. The solid was filtered and vacuum dried to obtain 45.8 g of ACCP fine product with a yield of 84.6% and a purity of 99.8%.

[0041] The recovered filtrate was placed in a 1000 mL three-necked flask, and 54.0 g of adiponitrile was slowly added at 60 °C at a rate of 2 mL / min. The reaction was kept warm for 4 h to obtain material B rich in 1-amino-2-cyano-1-cyclopentene (ACCP). Material B was cooled to 5 °C and allowed to stand for 3 h. After crystals were precipitated, the pressure was controlled at 0.3 MPa for pressure filtration to obtain 50.1 g of ACCP filter cake with a purity of 95.6%, and 527 mL of secondary filtrate was recovered. The obtained ACCP filter cake was dissolved in 200 mL of 1, 2-dichloroethane, heated and evaporated, and then cooled to 5 °C and allowed to stand for 3 h for crystallization. The solid was filtered and vacuum dried to obtain 45.3 g of ACCP fine product with a yield of 83.7% and a purity of 99.8%.

[0042] Example 8: Under nitrogen protection, 50.5 g of sodium tert-butoxide was added to a 1000 mL three-necked flask, followed by 560 mL of 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM] + PF 6 -), the two were stirred at 60 ° C for 0.4 h to obtain material A. At this temperature, 54.0 g of adiponitrile was slowly added to material A using a constant pressure dropping funnel at a dropping rate of 4 mL / min, and the reaction was kept warm for 4 h to obtain material B rich in 1-amino-2-cyano-1-cyclopentene (ACCP). Material B was cooled to 5 ° C and allowed to stand for 3 h. After crystals were precipitated, the pressure was controlled at 0.3 MPa for pressure filtration to obtain 52.7 g of ACCP filter cake with a purity of 95.7%, and 554 mL of filtrate was recovered. The obtained ACCP filter cake was dissolved in 200 mL of 1, 2-dichloroethane, heated and evaporated, and then cooled to 5 ° C and allowed to stand for 3 h to crystallize. The solid was filtered and vacuum dried to obtain 48.2 g of ACCP fine product with a yield of 89.1% and a purity of 99.8%.

[0043] The recovered filtrate was placed in a 1000 mL three-necked flask, and 54.0 g of adiponitrile was slowly added dropwise at 60 °C at a rate of 4 mL / min. The reaction was kept warm for 4 h to obtain material B rich in 1-amino-2-cyano-1-cyclopentene (ACCP). Material B was cooled to 5 °C and allowed to stand for 3 h. After crystals were precipitated, the pressure was controlled at 0.3 MPa for pressure filtration to obtain 51.9 g of ACCP filter cake with a purity of 95.3%, and 549 mL of secondary filtrate was recovered. The obtained ACCP filter cake was dissolved in 200 mL of 1, 2-dichloroethane, heated and evaporated, and then cooled to 5 °C and allowed to stand for 3 h for crystallization. The solid was filtered and vacuum dried to obtain 47.4 g of ACCP fine product with a yield of 87.6% and a purity of 99.8%.

[0044] Example 9: Under argon protection, 68.1 g of potassium tert-butoxide was added to a 5 L reactor, followed by 3040 mL of 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM] + PF 6 - ), the two were stirred at 70 ° C for 2 h to obtain material A. At this temperature, 86.4 g of adiponitrile was slowly added to material A using a constant pressure dropping funnel at a dropping speed of 2 mL / min, and the reaction was kept warm for 4 h to obtain material B rich in 1-amino-2-cyano-1-cyclopentene (ACCP). Material B was cooled to 5 ° C and allowed to stand for 3 h. After crystals were precipitated, the pressure was controlled at 0.3 MPa for pressure filtration to obtain 85.9 g of ACCP filter cake with a purity of 96.2%, and 3010 mL of filtrate was recovered. The obtained ACCP filter cake was dissolved in 300 mL of 1, 2-dichloroethane, heated and evaporated, and then cooled to 5 ° C and allowed to stand for 3 h for crystallization. The solid was filtered and vacuum dried to obtain 79.5 g of ACCP fine product with a yield of 91.9% and a purity of 99.8%.

[0045] The recovered filtrate was placed in a 1000 mL three-necked flask, and 86.4 g of adiponitrile was slowly added dropwise at 60 °C at a rate of 2 mL / min. The reaction was kept warm for 4 h to obtain material B rich in 1-amino-2-cyano-1-cyclopentene (ACCP). Material B was cooled to 5 °C and allowed to stand for 3 h. After crystals were precipitated, the pressure was controlled at 0.3 MPa for pressure filtration to obtain 84.3 g of ACCP filter cake with a purity of 96.1%. 2980 mL of filtrate was recovered for the second time. The obtained ACCP filter cake was dissolved in 300 mL of 1, 2-dichloroethane, heated and evaporated, and then cooled to -10 °C and allowed to stand for 20 h for crystallization. The solid was filtered and vacuum dried to obtain 77.6 g of ACCP fine product with a yield of 89.6% and a purity of 99.8%.

[0046] Example 10: Under nitrogen protection, 58.9 g of potassium tert-butoxide was added to a 500 mL three-necked flask, followed by 298 mL of 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM] + PF 6 - ), the two were stirred at 60 ° C for 0.5 h to obtain material A. At this temperature, 54.0 g of adiponitrile was slowly added to material A using a constant pressure dropping funnel at a dropping speed of 2 mL / min, and the reaction was kept warm for 4 h to obtain material B rich in 1-amino-2-cyano-1-cyclopentene (ACCP). Material B was cooled to 5 ° C and allowed to stand for 3 h. After crystals were precipitated, the pressure was controlled at 0.3 MPa for pressure filtration to obtain 55.4 g of ACCP filter cake with a purity of 96.4%, and 280 mL of filtrate was recovered. The obtained ACCP filter cake was dissolved in 200 mL of 1, 2-dichloroethane, heated and evaporated, and then cooled to 5 ° C and allowed to stand for 3 h to crystallize. The solid was filtered and vacuum dried to obtain 46.4 g of ACCP fine product with a yield of 85.7% and a purity of 99.7%.

[0047] The recovered filtrate was placed in a 500 mL three-necked flask, and 54.0 g of adiponitrile was slowly added dropwise at 60 °C at a rate of 2 mL / min. The reaction was kept warm for 4 h to obtain material B rich in 1-amino-2-cyano-1-cyclopentene (ACCP). Material B was cooled to 5 °C and allowed to stand for 3 h. After crystals were precipitated, the pressure was controlled at 0.3 MPa for pressure filtration to obtain 53.8 g of ACCP filter cake with a purity of 87.2%, and 263 mL of secondary filtrate was recovered. The obtained ACCP filter cake was dissolved in 200 mL of 1, 2-dichloroethane, heated and evaporated, and then cooled to 5 °C and allowed to stand for 3 h for crystallization. The solid was filtered and vacuum dried to obtain 45.2 g of ACCP fine product with a yield of 83.5% and a purity of 99.7%.

[0048] Example 11: Under nitrogen protection, 57.3 g of lithium diisopropylamide was added to a 1000 mL three-necked flask, followed by 560 mL of 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM] + PF 6 - ) and 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM] + BF 4 - ) mixed solution (v([BMIM] + PF 6 - ) / v([BMIM] + BF 4 - )=2 / 3), the two were stirred at 60 ° C for 0.5 h to obtain material A. At this temperature, 54.0 g of adiponitrile was slowly added to material A using a constant pressure dropping funnel at a dropping speed of 2 mL / min, and the reaction was kept warm for 4 h to obtain material B rich in 1-amino-2-cyano-1-cyclopentene (ACCP). Material B was cooled to 5 ° C and allowed to stand for 3 h. After crystals were precipitated, the pressure was controlled at 0.3 MPa for pressure filtration to obtain 52.9 g of ACCP filter cake with a purity of 95.8%, and 554.4 mL of filtrate was recovered. The obtained ACCP filter cake was dissolved in 200 mL of 1, 2-dichloroethane, heated and evaporated, and then cooled to 5 ° C and allowed to stand for 3 h for crystallization. The solid was filtered and vacuum dried to obtain 48.7 g of ACCP fine product with a yield of 90.1% and a purity of 99.9%.

[0049] The recovered filtrate was placed in a 1000 mL three-necked flask, and 54.0 g of adiponitrile was slowly added dropwise at 60 °C at a rate of 2 mL / min. The reaction was kept warm for 4 h to obtain material B rich in 1-amino-2-cyano-1-cyclopentene (ACCP). Material B was cooled to 5 °C and allowed to stand for 3 h. After crystals were precipitated, the pressure was controlled at 0.3 MPa for pressure filtration to obtain 52.4 g of ACCP filter cake with a purity of 95.6%, and 549 mL of secondary filtrate was recovered. The obtained ACCP filter cake was dissolved in 200 mL of 1, 2-dichloroethane, heated and evaporated, and then cooled to 5 °C and allowed to stand for 3 h for crystallization. The solid was filtered and vacuum dried to obtain 48.3 g of ACCP fine product with a yield of 89.3% and a purity of 99.8%.

[0050] Example 12: Under nitrogen protection, 28.6 g of lithium diisopropylamide and 22.1 g of potassium ethoxide were added to a 1000 mL three-necked flask, and then 560 mL of 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM] + PF 6- ) and 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM] + BF 4 - ) mixed solution (v([BMIM] + PF 6 - ) / v([BMIM] + BF 4 - )=2 / 3), the two were stirred at 60 ° C for 0.5 h to obtain material A. At this temperature, 54.0 g of adiponitrile was slowly added to material A using a constant pressure dropping funnel at a dropping speed of 2 mL / min, and the reaction was kept warm for 4 h to obtain material B rich in 1-amino-2-cyano-1-cyclopentene (ACCP). Material B was cooled to 5 ° C and allowed to stand for 3 h. After crystals were precipitated, the pressure was controlled at 0.3 MPa for pressure filtration to obtain 52.3 g of ACCP filter cake with a purity of 95.1%, and 548.8 mL of filtrate was recovered. The obtained ACCP filter cake was dissolved in 200 mL of 1, 2-dichloroethane, heated and evaporated, and then cooled to 5 ° C and allowed to stand for 3 h for crystallization. The solid was filtered and vacuum dried to obtain 47.1 g of ACCP fine product, with a total reaction yield of 87.0% and a purity of 99.8%.

[0051] The recovered filtrate was placed in a 1000 mL three-necked flask, and 54.0 g of adiponitrile was slowly added at 60 °C at a rate of 2 mL / min. The reaction was kept warm for 4 h to obtain material B rich in 1-amino-2-cyano-1-cyclopentene (ACCP). Material B was cooled to 5 °C and allowed to stand for 3 h. After crystals were precipitated, the pressure was controlled at 0.3 MPa for pressure filtration to obtain 52.0 g of ACCP filter cake with a purity of 95.2%, and 538 mL of secondary filtrate was recovered. The obtained ACCP filter cake was dissolved in 200 mL of 1, 2-dichloroethane, heated and evaporated, and then cooled to 5 °C and allowed to stand for 3 h for crystallization. The solid was filtered and vacuum dried to obtain 46.9 g of ACCP fine product, with a total reaction yield of 86.6% and a purity of 99.7%.

[0052] The above Experimental Examples 1 to 12 found that the type and amount of ionic liquid added and the selection of super strong organic base would not significantly affect the quality and yield of 1-amino-2-cyano-1-cyclopentene, and the recovery rate of the filtrate recirculation reaction was maintained at a high level.

[0053] Comparative Example 1: 54.0 g of adiponitrile was added to a dry 1000 mL jacketed three-necked flask, and then 560 g of toluene was added as solvent, and the mixture was reacted at 60 °C for 0.5 h, followed by adding 50.5 g of sodium tert-butoxide, and the mixture was heated to 60 °C and stirred for 2.5 h. After the reaction was completed, water was added to the obtained solid-liquid mixture, the solid was filtered and vacuum dried to obtain 40.1 g of ACCP product, with a reaction yield of 69.4% and a purity of 93.4%.

[0054] Comparative Example 2: Add 54.0 g of adiponitrile to a dry 250 mL jacketed three-necked flask, then add 54 g of toluene as solvent, react at 60 °C for 0.5 h, then add 50.5 g of sodium tert-butoxide, heat to 100 °C and stir for 2.5 h. After the reaction is completed, add water to the obtained solid-liquid mixture, filter the solid and vacuum dry to obtain 51.8 g of ACCP product, with a reaction yield of 86.7% and a purity of 90.4%.

[0055] From Comparative Examples 1 and 2, it was found that in the toluene system, the yield was low at 60°C, and the temperature had to be raised to 100°C to improve.

[0056] In summary, the present invention provides a method for synthesizing 1-amino-2-cyano-1-cyclopentene. Under a protective gas atmosphere, a mixed system of an ionic liquid and a super organic base is constructed, the reaction is mild, and the product is separated from the mixed system of the ionic liquid and the super organic base by pressure filtration, and the product yield is high and the purity is high. The separated ionic liquid and the super organic base can be back-reacted, and the yield and purity of the back-reaction do not change much. Therefore, the entire preparation process has a mild temperature, simple steps, efficient reaction, convenient post-processing, high product yield, high purity, and more importantly, less three wastes, which effectively solves the problem of solvent recovery, greatly reduces production costs, effectively avoids pollution to the environment, and is suitable for industrial production.

Claims

1. A method for synthesizing 1-amino-2-cyano-1-cyclopentene, characterized in that: The steps include:

1. In a protective gas atmosphere, the ionic liquid and the super strong organic base are mixed, heated and stirred, and mixed and dissolved to obtain material A; the ionic liquid is selected from at least one of [BMIM]PF6, [BMIM]BF4, [BMIM]NTf2, [BMIM]OTf, and [BMIM]OAc; 2. adding adiponitrile dropwise into the stirred material A to react, thereby obtaining a material B rich in 1-amino-2-cyano-1-cyclopentene; 3. Cooling and crystallizing material B, and filtering under pressure to obtain crude ACCP; 4. The obtained crude ACCP is purified by recrystallization to obtain a pure product.

2. A method for synthesizing 1-amino-2-cyano-1-cyclopentene according to claim 1, characterized in that: The filtrate obtained by pressure filtration in the third step is recycled for the next round of reaction.

3. A method for synthesizing 1-amino-2-cyano-1-cyclopentene according to claim 1 or 2, characterized in that: In the first step, the super strong organic base is at least one of potassium tert-butoxide, sodium tert-butoxide, lithium bis(trimethylsilyl)amide, n-butyl lithium, lithium diisopropylamide, potassium methoxide, and potassium ethoxide.

4. A method for synthesizing 1-amino-2-cyano-1-cyclopentene according to claim 3, characterized in that: The ratio of the volume of the ionic liquid to the molar amount of the super strong organic base is 0.5~5.0:1, wherein the volume unit of the ionic liquid is liter and the molar amount unit of the super strong organic base is mole.

5. A method for synthesizing 1-amino-2-cyano-1-cyclopentene according to claim 1 or 2, characterized in that: In the first step, the protective gas is nitrogen or argon.

6. A method for synthesizing 1-amino-2-cyano-1-cyclopentene according to claim 1 or 2, characterized in that: In the first step, the heating and stirring time is 0.4 to 2.0 hours, and the temperature is 60 to 80°C.

7. A method for synthesizing 1-amino-2-cyano-1-cyclopentene according to claim 1 or 2, characterized in that: In the second step, the adiponitrile dropping speed is 1-4 mL / min, and the temperature is controlled at 60-80 °C during the dropping.

8. A method for synthesizing 1-amino-2-cyano-1-cyclopentene according to claim 1 or 2, characterized in that: In the second step, the molar ratio of adiponitrile to super strong organic base is 0.8-1.

7.

9. A method for synthesizing 1-amino-2-cyano-1-cyclopentene according to claim 1 or 2, characterized in that: In the third step, the crystallization temperature is controlled at -10 ℃ ~ 5 ℃.

10. A method for synthesizing 1-amino-2-cyano-1-cyclopentene according to claim 1 or 2, characterized in that: In the third step, the pressure during the pressure filtration is 0.3-0.45 MPa under a protective gas atmosphere.

11. A method for synthesizing 1-amino-2-cyano-1-cyclopentene according to claim 1 or 2, characterized in that: In the fourth step, the recrystallization and purification step includes: dissolving the crude ACCP in an organic solvent, heating to evaporate and concentrate, cooling to crystallize, filtering, and vacuum drying.

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