Method for preparing cyclohexene

Abstract

The invention provides a method for preparing cyclohexene. The method comprises the following steps: providing dicyclohexyl ether; performing a cracking reaction on the dicyclohexyl ether under the action of a catalyst so as to obtain a cracking product; cooling the cracking product to 60 DEG C or lower, performing oil-water separation, and distilling an oil-phase product, thereby obtaining cyclohexene. By adopting the method for preparing the cyclohexene, the conversion rate of the dicyclohexyl ether and the selectivity of the cyclohexene are relatively high when being compared with those ofdicyclohexyl ether, in addition, the cyclohexene can be prepared by distilling and purifying a reaction product, and later separation procedures are simple.

Description

technical field

[0001] The invention relates to the technical field of chemical synthesis, in particular to a method for preparing cyclohexene. Background technique

[0002] Asahi Kasei Corporation of Japan developed a high-efficiency hydrated molecular sieve catalyst in 1986, which reacted cyclohexene with water to directly prepare cyclohexanol. At present, there are many sets of cyclohexanol production equipment in China using this process. The conversion rate of cyclohexene in this process is about 10%, and the selectivity of cyclohexanol reaches 99%. Since olefins and alcohols are prone to form ether reactions under the action of molecular sieves, the cyclohexanol generated in this process will further undergo addition etherification reaction with cyclohexene to form dicyclohexyl ether. The specific reaction process is as follows:

[0003]

[0004] Since the generation process of cyclohexanol to cyclohexanone is very strict on the control of impurities, the substa...

Examples

preparation example Construction

[0029] The preparation method of cyclohexene of one embodiment, comprises the following steps S110~S140:

[0030] S110, providing dicyclohexyl ether.

[0031] In this embodiment, dicyclohexyl ether is prepared by the following method:

[0032] (1) Fuel oil is provided, which is produced during the preparation of cyclohexanol by cyclohexene hydration.

[0033] Specifically, the fuel oil contains cyclohexane, methylcyclopentane, cyclohexene, cyclohexanol and dicyclohexyl ether.

[0034] (2) Rectifying and purifying the above-mentioned fuel oil to obtain dicyclohexyl ether.

[0035] Specifically, dicyclohexyl ether can be obtained by sequentially performing normal-pressure rectification and negative-pressure rectification on the above-mentioned fuel oil.

[0036] Further, the conditions of atmospheric distillation are: top temperature 70°C~90°C, reflux ratio 3~10:1.

[0037] The conditions of negative pressure distillation are: pressure 0.1KPa~5KPa, reflux ratio 3~10:1, top t...

Embodiment 1

[0053] The fuel oil containing 1% methylcyclopentane, 15% cyclohexane, 5% cyclohexene, 35% cyclohexanol and 44% dicyclohexyl ether is sequentially subjected to atmospheric distillation and negative pressure Rectification, normal pressure rectification to obtain the light component fraction section, negative pressure rectification to obtain the cyclohexanol fraction section and the dicyclohexyl ether fraction section respectively. Among them, the content of cyclohexanol in the cyclohexanol fraction section is >99.5%, and the content of dicyclohexyl ether in the dicyclohexyl ether fraction section is 87%.

[0054] React the dicyclohexyl ether fraction above in a fixed-bed reactor equipped with a potassium carbonate catalyst at a reaction temperature of 280°C and a space velocity of 0.2h -1 , the reaction pressure is 0MPa, and the cleavage product is obtained.

[0055] Cool the cracked product above to below 60°C, separate the oil from water, take the oil phase for rectification...

Embodiment 2

[0067] The fuel oil containing 1% methylcyclopentane, 15% cyclohexane, 5% cyclohexene, 35% cyclohexanol and 44% dicyclohexyl ether is sequentially subjected to atmospheric distillation and negative pressure Rectification, normal pressure rectification to obtain the light component fraction section, negative pressure rectification to obtain the cyclohexanol fraction section and the dicyclohexyl ether fraction section respectively. Among them, the content of cyclohexanol in the cyclohexanol fraction section is >99.5%, and the content of dicyclohexyl ether in the dicyclohexyl ether fraction section is 87%.

[0068] React the dicyclohexyl ether fraction above in a fixed-bed reactor equipped with a 4A molecular sieve catalyst at a reaction temperature of 330°C and a space velocity of 0.3h -1 , the reaction pressure is 0.2MPa, and the cracked product is obtained.

[0069] Cool the cracked product above to below 60°C, separate the oil from water, take the oil phase for rectification...

technical field

[0001] The invention relates to the technical field of chemical synthesis, in particular to a method for preparing cyclohexene. Background technique

[0002] Asahi Kasei Corporation of Japan developed a high-efficiency hydrated molecular sieve catalyst in 1986, which reacted cyclohexene with water to directly prepare cyclohexanol. At present, there are many sets of cyclohexanol production equipment in China using this process. The conversion rate of cyclohexene in this process is about 10%, and the selectivity of cyclohexanol reaches 99%. Since olefins and alcohols are prone to form ether reactions under the action of molecular sieves, the cyclohexanol generated in this process will further undergo addition etherification reaction with cyclohexene to form dicyclohexyl ether. The specific reaction process is as follows:

[0003]

[0004] Since the generation process of cyclohexanol to cyclohexanone is very strict on the control of impurities, the substa...

Examples

preparation example Construction

[0029] The preparation method of cyclohexene of one embodiment, comprises the following steps S110~S140:

[0030] S110, providing dicyclohexyl ether.

[0031] In this embodiment, dicyclohexyl ether is prepared by the following method:

[0032] (1) Fuel oil is provided, which is produced during the preparation of cyclohexanol by cyclohexene hydration.

[0033] Specifically, the fuel oil contains cyclohexane, methylcyclopentane, cyclohexene, cyclohexanol and dicyclohexyl ether.

[0034] (2) Rectifying and purifying the above-mentioned fuel oil to obtain dicyclohexyl ether.

[0035] Specifically, dicyclohexyl ether can be obtained by sequentially performing normal-pressure rectification and negative-pressure rectification on the above-mentioned fuel oil.

[0036] Further, the conditions of atmospheric distillation are: top temperature 70°C~90°C, reflux ratio 3~10:1.

[0037] The conditions of negative pressure distillation are: pressure 0.1KPa~5KPa, reflux ratio 3~10:1, top t...

Embodiment 1

[0053] The fuel oil containing 1% methylcyclopentane, 15% cyclohexane, 5% cyclohexene, 35% cyclohexanol and 44% dicyclohexyl ether is sequentially subjected to atmospheric distillation and negative pressure Rectification, normal pressure rectification to obtain the light component fraction section, negative pressure rectification to obtain the cyclohexanol fraction section and the dicyclohexyl ether fraction section respectively. Among them, the content of cyclohexanol in the cyclohexanol fraction section is >99.5%, and the content of dicyclohexyl ether in the dicyclohexyl ether fraction section is 87%.

[0054] React the dicyclohexyl ether fraction above in a fixed-bed reactor equipped with a potassium carbonate catalyst at a reaction temperature of 280°C and a space velocity of 0.2h -1 , the reaction pressure is 0MPa, and the cleavage product is obtained.

[0055] Cool the cracked product above to below 60°C, separate the oil from water, take the oil phase for rectification...

Embodiment 2

[0067] The fuel oil containing 1% methylcyclopentane, 15% cyclohexane, 5% cyclohexene, 35% cyclohexanol and 44% dicyclohexyl ether is sequentially subjected to atmospheric distillation and negative pressure Rectification, normal pressure rectification to obtain the light component fraction section, negative pressure rectification to obtain the cyclohexanol fraction section and the dicyclohexyl ether fraction section respectively. Among them, the content of cyclohexanol in the cyclohexanol fraction section is >99.5%, and the content of dicyclohexyl ether in the dicyclohexyl ether fraction section is 87%.

[0068] React the dicyclohexyl ether fraction above in a fixed-bed reactor equipped with a 4A molecular sieve catalyst at a reaction temperature of 330°C and a space velocity of 0.3h -1 , the reaction pressure is 0.2MPa, and the cracked product is obtained.

[0069] Cool the cracked product above to below 60°C, separate the oil from water, take the oil phase for rectification...

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