Method for directly synthesizing cyclohexanol by nitrobenzene hydrogenation

Abstract

The invention discloses a method for directly synthesizing cyclohexanol by nitrobenzene hydrogenation. The method comprises the following steps: putting nitrobenzene, a catalyst, water and tert-butyl alcohol into a high pressure reactor, and introducing N2 for replacement; heating to 140-200 DEG C, introducing hydrogen to 4-8 MPa and keeping, reacting for 4-16h, stopping introducing hydrogen, cooling to room temperature, carrying out vacuum filtration to separate the catalyst and a reaction solution, and carrying out extraction separation on the reaction solution to obtain an organic phase containing cyclohexanol, wherein molar ratio of nitrobenzene to the catalyst to water to tert-butyl alcohol is 1:0.0005-0.05:1-10000:0.01-10; and the catalyst is a supported metal catalyst. The method has characteristics as follows: the raw material nitrobenzene is cheap and easily available; the synthesis process is simpler; and reaction yield is high. Reaction conditions are simple and clean, and yield of cyclohexanol is close to 100%.

Description

technical field

[0001] The invention relates to a new method for directly synthesizing cyclohexanol by hydrogenation of nitrobenzene, specifically a process for directly synthesizing cyclohexanol by using nitrobenzene as a raw material and catalyzing the hydrogenation of nitrobenzene with a supported metal catalyst. It belongs to the technical field of chemical technology. Background technique

[0002] Cyclohexanol is an important organic chemical raw material and an important intermediate for the synthesis of caprolactam, adipic acid, and fine chemicals such as medicine, paint, and dye.

[0003] At present, there are generally three methods for the synthesis of cyclohexanol. (1) Using phenol as a raw material, one-step catalytic hydrogenation to prepare cyclohexanol is relatively simple, but it is limited due to the high price of phenol. (2) Using benzene as a raw material, complete hydrogenation to obtain cyclohexane, and further oxidation to obtain cyclohexanol or cyclo...

Examples

Embodiment 1

[0024] 2.0g of nitrobenzene, 0.41g of 2% (wt) Ru / MCM-41 (molecular sieve) catalyst, 170ml of water and 10ml of tert-butanol were successively added into the autoclave (the molar ratio was 1:0.005:583:6.5). Pass N 2 Make a replacement. Then the temperature was raised to 180° C., and then hydrogen gas was introduced until the reaction pressure was 4.4 MPa. After 8 hours of reaction, the hydrogen gas flow was stopped and the temperature was lowered. The catalyst and the reaction solution were separated by filtration under reduced pressure, and the reaction solution was extracted and separated by toluene to obtain an organic phase, which was analyzed by gas chromatography. The yield of product cyclohexanol was 99.7% according to quantitative calculation.

Embodiment 2

[0026] Add 2.0 g of nitrobenzene, 0.41 g of 2% Ru / AC catalyst, 170 ml of water and 10 ml of tert-butanol (the molar ratio is 1:0.005:583:6.5) in the autoclave. Pass N 2 Make a replacement. Then the temperature was raised to 180° C., and then hydrogen gas was introduced until the reaction pressure was 4.4 MPa. After 8 hours of reaction, the hydrogen gas flow was stopped and the temperature was lowered. The catalyst and the reaction solution were separated by filtration under reduced pressure, and the reaction solution was extracted and separated by toluene to obtain an organic phase, which was analyzed by gas chromatography. Quantitative calculation yield of product cyclohexanol is 100%.

Embodiment 3

[0028] In the autoclave, add nitrobenzene 2.0g, 2%Ru / SiO 2 Catalyst 0.41g, water 170ml and tert-butanol 10ml (the molar ratio is 1:0.005:583:6.5). Pass N 2 Make a replacement. Then the temperature was raised to 180° C., and then hydrogen gas was introduced until the reaction pressure was 4.4 MPa. After 8 hours of reaction, the hydrogen gas flow was stopped and the temperature was lowered. The catalyst and the reaction solution were separated by filtration under reduced pressure, and the reaction solution was extracted and separated by toluene to obtain an organic phase, which was analyzed by gas chromatography. The yield of the product cyclohexanol by quantitative calculation is 99.8%.

technical field

[0001] The invention relates to a new method for directly synthesizing cyclohexanol by hydrogenation of nitrobenzene, specifically a process for directly synthesizing cyclohexanol by using nitrobenzene as a raw material and catalyzing the hydrogenation of nitrobenzene with a supported metal catalyst. It belongs to the technical field of chemical technology. Background technique

[0002] Cyclohexanol is an important organic chemical raw material and an important intermediate for the synthesis of caprolactam, adipic acid, and fine chemicals such as medicine, paint, and dye.

[0003] At present, there are generally three methods for the synthesis of cyclohexanol. (1) Using phenol as a raw material, one-step catalytic hydrogenation to prepare cyclohexanol is relatively simple, but it is limited due to the high price of phenol. (2) Using benzene as a raw material, complete hydrogenation to obtain cyclohexane, and further oxidation to obtain cyclohexanol or cyclo...

Examples

Embodiment 1

[0024] 2.0g of nitrobenzene, 0.41g of 2% (wt) Ru / MCM-41 (molecular sieve) catalyst, 170ml of water and 10ml of tert-butanol were successively added into the autoclave (the molar ratio was 1:0.005:583:6.5). Pass N 2 Make a replacement. Then the temperature was raised to 180° C., and then hydrogen gas was introduced until the reaction pressure was 4.4 MPa. After 8 hours of reaction, the hydrogen gas flow was stopped and the temperature was lowered. The catalyst and the reaction solution were separated by filtration under reduced pressure, and the reaction solution was extracted and separated by toluene to obtain an organic phase, which was analyzed by gas chromatography. The yield of product cyclohexanol was 99.7% according to quantitative calculation.

Embodiment 2

[0026] Add 2.0 g of nitrobenzene, 0.41 g of 2% Ru / AC catalyst, 170 ml of water and 10 ml of tert-butanol (the molar ratio is 1:0.005:583:6.5) in the autoclave. Pass N 2 Make a replacement. Then the temperature was raised to 180° C., and then hydrogen gas was introduced until the reaction pressure was 4.4 MPa. After 8 hours of reaction, the hydrogen gas flow was stopped and the temperature was lowered. The catalyst and the reaction solution were separated by filtration under reduced pressure, and the reaction solution was extracted and separated by toluene to obtain an organic phase, which was analyzed by gas chromatography. Quantitative calculation yield of product cyclohexanol is 100%.

Embodiment 3

[0028] In the autoclave, add nitrobenzene 2.0g, 2%Ru / SiO 2 Catalyst 0.41g, water 170ml and tert-butanol 10ml (the molar ratio is 1:0.005:583:6.5). Pass N 2 Make a replacement. Then the temperature was raised to 180° C., and then hydrogen gas was introduced until the reaction pressure was 4.4 MPa. After 8 hours of reaction, the hydrogen gas flow was stopped and the temperature was lowered. The catalyst and the reaction solution were separated by filtration under reduced pressure, and the reaction solution was extracted and separated by toluene to obtain an organic phase, which was analyzed by gas chromatography. The yield of the product cyclohexanol by quantitative calculation is 99.8%.

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