CN101318911A - A kind of preparation method of N-cyclohexenyl cyclohexyl imine - Google Patents

Abstract

The invention discloses a preparation method for N- cyclohexenyl cyclohexylimine. The method is as follows: under the action of catalyst, the N- cyclohexenyl cyclohexylimine is produced by reacting cyclohexanone with ammonia in an organic solvent, according to a molar ratio of the cyclohexanone to the ammonia of 1: 0.8-3.5, which is carried out at a temperature of between 50 and 80 DEG C, under the atmospheric pressure for 1 to 5 hours. The method for preparing the N- cyclohexenyl cyclohexylimine is characterized by simple process, environment protection, and low cost, etc.

Description

A kind of preparation method of N-cyclohexenyl cyclohexyl imine

technical field

The invention relates to a preparation method of an organic compound, in particular to a preparation method of N-cyclohexenylcyclohexyl imine.

Background technique

N-cyclohexenylcyclohexylimine, whose structural formula is shown in Formula 1, is a chemical synthesis intermediate, which is an important raw material for the synthesis of chiral compounds and asymmetric addition, and can also be used as a latent curing agent to improve water resistance. The performance of polyurethane can also be used as a semi-latent curing agent for epoxy resin paint.

Formula 1

The preparation method of N-cyclohexenylcyclohexyl imine has not been reported yet. The usual method for preparing imines is to react organic amines with ketones or aldehydes to generate imines. In this type of reaction, imines with substituents on nitrogen are obtained. In the reaction process, relatively high-priced organic amines ( See Tetrahcdmn: Asymmetry, Vol. 8, No. 20, 3457-3466, 1997).

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for preparing N-cyclohexenylcyclohexyl imine with low production cost and environmental friendliness.

In order to solve the above-mentioned technical problem, the present invention provides a kind of preparation method of N-cyclohexenyl cyclohexyl imine, under the action of neutralization catalyst in organic solvent, cyclohexanone and ammonia react to generate N-cyclohexenyl cyclohexyl imine Amine; the reaction time is 1 to 5 hours, the temperature is 50 to 80° C., the molar ratio of cyclohexanone to ammonia is 1:0.8 to 3.5, and the reaction pressure is normal pressure.

As an improvement of the preparation method of N-cyclohexenylcyclohexylimine of the present invention: the catalyst is a transition metal oxide made of Al ₂ O ₃ loaded active components, and the active components are CuO, ZnO, ZrO, Cr ₂ O ₃ or TiO ₂ , the active component is used in an amount of 0.5-2.5% of the mass of cyclohexanone.

As a further improvement of the preparation method of N-cyclohexenylcyclohexylimine of the present invention: the active component accounts for 5-10% of the total weight of the transition metal oxide.

As a further improvement of the preparation method of N-cyclohexenylcyclohexylimine of the present invention: the ammonia is ammonia water with a mass concentration of 10% to 35%.

As a further improvement of the preparation method of N-cyclohexenylcyclohexylimine of the present invention: the organic solvent is a solvent immiscible with water, and its dosage is 0.5 to 2 times the volume of cyclohexanone. The water-immiscible solvent can be cyclohexane, n-hexane, benzene, toluene or xylene and the like.

Reaction formula of the present invention is as follows:

The catalyst used in the reaction process is a transition metal oxide, which is CuO, ZnO, ZrO, Cr ₂ O ₃ , TiO ₂ supported by Al ₂ O ₃ , the active component content is 5-10%, and its shape can be small balls or Powder, its preparation method refers to Chinese Journal of Catalysis, Vol.29, NO.1, 25-30. The used catalyst can be recycled after being calcined at 200-550°C for 1-5 hours in the air; the optimum calcining temperature is 350°C, and the optimum calcining time is 3 hours.

In the present invention, the preferred amount of catalyst (specifically referring to the active component therein) is 1.2% of the quality of cyclohexanone, the preferred amount of organic solvent is 0.8 to 1.5 times the volume of cyclohexanone, and the preferred ammonia concentration The mass fraction is 20-25%, and the better reaction temperature is 60°C.

The product prepared by adopting the method of the present invention is determined to be N-cyclohexenylcycloheximine through mass spectrometer analysis. The method has the advantages of simple steps, environmental friendliness and low cost, and the yield can be as high as 29.2%.

Detailed ways

Embodiment 1, a kind of preparation method of N-cyclohexenyl cyclohexyl imine, take cyclohexanone and ammonia as starting raw material, carry out following steps successively:

In a still with a volume of 250mL, add CuO/Al ₂ O ₃ containing 0.35gCuO as a catalyst, and the weight content of CuO in the catalyst is 5% (that is, CuO accounts for 5% of the total weight of the catalyst); add 20mL of ring Hexane was used as an organic solvent. 20 mL of cyclohexanone (0.19 mol, 18.9 g) was fed at one time, and then heated to a reaction temperature of 60° C., and 35 mL of ammonia water with a mass fraction of 25% was continuously added at a rate of 30 g/h. During this period, the temperature of the reaction system was maintained at 60°C. After reacting for 3 hours, the reaction was terminated; the upper layer of the liquid taken out from the still was analyzed by gas chromatography. Analysis showed that the conversion of cyclohexanone was 27.4% and the yield was 25.8%.

During separation, distill the water from the obtained still liquid under normal pressure, and then distill it under 10kPa, and collect the distillate between 155.2 and 156.8°C as the product.

The catalyst filtered out after the above-mentioned reaction can choose any of the following to reuse,

Mode 1, direct reuse, that is, directly used again in the preparation method of N-cyclohexenylcyclohexylimine; the catalyst filtered out in the reaction with a yield of not less than 20% can be recycled 6 times.

Method 2, after processing, so as to realize recycling; the processing method is as follows:

Calcined in air at a temperature of 350° C. for 3 hours to obtain a calcined catalyst; the recovery rate reached 82.4%. The calcined catalyst is used in the preparation method of N-cyclohexenylcyclohexylimine; it can also be reused directly for 6 times.

Embodiment 2～10:

Change the following reaction conditions in embodiment 1: the kind of catalyst and the weight content (being called for short catalyst) of active component in catalyzer, the weight (being called for short m1) of active component in catalyzer, the kind of solvent (being called for short solvent), the consumption of solvent ( Be called for short V1), reaction temperature (abbreviated T), the volume consumption of ammonia liquor (abbreviated V2), the mass fraction of ammonia in ammonia water (abbreviated mass content), reaction time (abbreviated t); Obtain embodiment 2～10, thereby obtain corresponding Cyclohexanone conversion (abbreviated as x), yield (abbreviated as y). The catalyst filtered out after the reaction of each example is used in mode 1, and the number of times the catalyst can be recycled (n1 for short); or the catalyst filtered out after the reaction is used in mode 2, and the catalyst can be obtained. Catalyst recovery rate (abbreviated as r) and recyclable times (referred to as n2). Please refer to Table 1 for details and results.

Table 1

Example number 1 2 3 4 5 catalyst CuO/ _Al2O3 ( ₆ %) ZnO/Al ₂ O ₃ (10%) ZrO/Al ₂ O ₃ (8%) Cr ₂ O ₃ /Al ₂ O ₃ (7%) TiO ₂ /Al ₂ O ₃ (5%) m1(g) 0.35 0.3 0.25 0.4 0.2 Solvent Cyclohexane n-Hexane Benzene Toluene Xylene V1(mL) 20 30 16 40 25 T(°C) 60 50 65 70 55 V2(mL) 35 30 20 25 30 Mass content 25% 30% 35% 20% 20% T(h) 3 3.5 2 2.5 3 x 27.4% 26.5% 25.8% 26.6% 26.8%

y 25.8% 24.8% 24.4% 25.2% 25.7% n1(times) 6 4 3 5 6 r 82.4% 83.2% 85.0% 83.7% 83.6% n2(times) 6 4 3 5 6 Example number 6 7 8 9 10 catalyst CuO/ _Al2O3 ( ₆ %) ZnO/Al ₂ O ₃ (10%) ZrO/Al ₂ O ₃ (8%) Cr2O3/ _Al2O3 ( ₇ %) TiO2/ _Al2O3 ( ₅ %) m1(g) 0.35 0.3 0.25 0.4 0.2 Solvent Cyclohexane n-Hexane Benzene Toluene Xylene V1(mL) 20 30 16 40 25 T(°C) 70 60 75 80 65 V2(mL) 35 30 20 25 30 Mass content 25% 30% 35% 20% 20% T(h) 3 3.5 2 2.5 3 x 26.5% 28.3% 24.5% 24.7% 30.5% y 24.9% 26.8% 22.2% 21.3% 29.2% n1(times) 5 5 2 3 7 r 81.4% 83.3% 81.5% 82.1% 82.6% n2(times) 5 5 2 3 7

Finally, it should be noted that the above examples are only some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and many variations are possible. All deformations that can be directly derived or associated by those skilled in the art from the content disclosed in the present invention should be considered as the protection scope of the present invention.

Claims (6)

1, a kind of preparation method of N-cyclohexenyl cyclohexyl imine, it is characterized in that: under the action of catalyst in organic solvent, cyclohexanone and ammonia react to generate N-cyclohexenyl cyclohexyl imine; Reaction The time is 1-5 hours, the temperature is 50-80° C., the molar ratio of cyclohexanone and ammonia is 1:0.8-3.5, and the reaction pressure is normal pressure. 2. The preparation method of N-cyclohexenylcyclohexylimine according to claim 1, characterized in that: the catalyst is a transition metal oxide made of Al ₂ O ₃ loaded active components, the active group It is divided into CuO, ZnO, ZrO, Cr ₂ O ₃ or TiO ₂ , and the dosage of the active component is 0.5-2.5% of the mass of cyclohexanone. 3. The method for preparing N-cyclohexenylcyclohexyl imine according to claim 2, characterized in that: the active component accounts for 5-10% of the total weight of the transition metal oxide. 4. The method for preparing N-cyclohexenylcyclohexyl imine according to claim 3, characterized in that: said ammonia is ammonia water with a mass concentration of 10%-35%. 5. The method for preparing N-cyclohexenylcyclohexylimine according to claim 4, characterized in that: the organic solvent is a solvent immiscible with water, and the amount used is 0.5-2% of the volume of cyclohexanone. times. 6. The method for preparing N-cyclohexenylcyclohexylimine according to claim 5, characterized in that: the water-immiscible solvent is cyclohexane, n-hexane, benzene, toluene or xylene.