Background and overview[1]
Cyclohexanemethanol has similar chemical properties to other alcohols and can undergo oxidation, esterification, etherification, halogenation reactions, etc. Cyclohexanemethanol and 4-methylthio-2-oxobutyric acid can undergo an esterification reaction to form cyclohexylmethyl 4-methylthio-2-oxobutyrate, which can be used to treat liver, kidney, pancreas and brain disease; the esterification reaction of 4-hydroxybenzoic acid and cyclohexanemethanol produces 4-hydroxybenzoic acid cyclohexylmethyl ester, which can then undergo aminomethylation reaction with tetrahydropyrrole and formaldehyde aqueous solution to produce hydroxybis(pyrrolidinylmethyl) Cyclohexylmethyl benzoate, this compound can be prepared into antiarrhythmic drugs; hydroxypolyethoxymethylcyclohexyl-n-octane can be synthesized using cyclohexanemethanol, and the sodium salt of this substance is a biodegradable arkema solution. agent and can be used to treat sewage; cyclohexanemethanol can also undergo glycosylation reactions to prepare it as an immunoglobulin inhibitor.
Preparation[1-2]
Report 1,
The preparation method of the reducing agent includes the following steps: put 45 grams of anhydrous zinc chloride into a 500ml three-neck reaction bottle, burn it in an oil bath at 200-220°C for 2 hours, cool it naturally to room temperature, and add anhydrous ml of tetrahydrofuran, stir for 0.5 to 1 hour to dissolve, cool to below 10°C, add 28 grams of potassium borohydride in three batches, stir at room temperature of 20 to 30°C for 3 to 4 hours, and set aside.
Reduction reaction: Cool the reduction solution prepared in the above step below 10°C, add dropwise 25 grams of cyclohexanecarboxylic acid and 100 ml of anhydrous tetrahydrofuran solution, complete the dripping, stir and reduce at room temperature for 4 hours, and then evaporate 200 ml of tetrahydrofuran. , cool slightly to room temperature, add ml of anhydrous toluene, continue to steam out tetrahydrofuran and a small amount of toluene, until the liquid temperature in the reaction bottle reaches 91~94°C, stop distillation, change to reflux, and keep the reaction for 8 hours, and a white solid will appear in the bottle It turns into an off-white solid, cool to below 10°C, continue to add 280 grams of 10% sodium hydroxide solution dropwise, and stir for 0.5 to 1 hour after the dropwise addition, and then continue to dropwise add 95 to 100ml of concentrated hydrochloric acid below 20°C. After the dripping is completed, stir for 0.5 hours, adjust the pH to 6-7, filter, wash with toluene, and let the solution stand to separate layers. The upper layer of toluene is washed once with 100 ml of water, and the water layer is separated. The toluene layer is dried with 30 grams of anhydrous sodium sulfate for 3 to 5 hours, filtered, and fractionated under normal pressure to recover solvent toluene with temperatures of 90 to 110°C and 110 to 120°C. , the front fractions with temperatures of 100-110°C and 110-165°C were recovered, and the fractions with temperatures of 165-180°C were collected as the product cyclohexanemethanol. A total of 23 grams was obtained, with a yield of 100%.
Report 2,
Figure 1: Schematic diagram of a process for hydrogenating benzyl alcohol to prepare cyclohexanemethanol; R101: first reactor, R102: second reactor, R103: third reactor, MX101: mixer, E101: pre- Heater, E102: reaction product cooler, V101: separation tank, K101: hydrogen compressor, T101: light removal tower, T102: cyclohexanmethanol tower, E103: T101 overhead condenser, E104: T101 reboiler, E201 : T102 overhead condenser, E202: T102 reboiler.
The new hydrogen and the hydrogen from the separation tank V101 are mixed and compressed to the appropriate pressure by the hydrogen compressor K101, and mixed with the benzyl alcohol raw material in the mixer MX101. The hydrogen-to-oil ratio is 300:1. After mixing, the material enters the preheating Reactor E101 completely vaporizes the material, and then enters the first reactor R101 for hydrogenation reaction. The reaction pressure is 0.2MPa, the temperature is 200°C, and the space velocity is 0.2h-1. The reaction product enters the second reactor R102 for further reaction. The hydrogen-to-oil ratio It is 300:1, the reaction pressure is 0.15MPa, the temperature is 200℃, the space velocity is 1h-1, the bottom material of the second reactor enters the third reactor R103 and continues to react to the end of the reaction, the hydrogen to oil ratio is 300:1, the reaction pressure is 0.1MPa , temperature 170℃, airspeed 2h-1. The bottom material of R103 enters the T101 reboiler E104 and the T102 reboiler E202 to provide heat, and is cooled by the reaction product cooler E102 before entering the separation tank V101 for gas-liquid separation. The gas phase returns to K101, and the liquid phase enters the light removal tower T101 as raw material. The operating pressure is 0.01MPa. After the gas phase at the top of the T101 tower is condensed and cooled by the phthalocyanine pigment top condenser E103 of the T101 tower, the non-condensable gas is discharged. Part of the condensate is refluxed, and part of it is extracted as light components. Unreacted benzyl alcohol is extracted from the side line. Return to MX101 and mix with hydrogen to continue the reaction. The material from the tower still enters the cyclohexanemethanol tower T102 with an operating pressure of 0.01MPa. The cyclohexanemethanol product is taken out from the top of T102 tower and the heavy components are discharged from the tower still.
The catalyst used in the reactor is a supported Ni-Ru catalyst.
The conversion rate of benzyl alcohol is 70%, and the selectivity of cyclohexylmethanol is 90%.
The purity of the purified cyclohexanemethanol is 99.99%, and the yield is 95%.
References
[1] [Chinese invention] CN201910884934.9 A process for preparing cyclohexylmethanol by hydrogenating benzyl alcohol
[2] [Invented in China] CN201810600370.7 A synthesis method of cyclohexanemethanol
