CN113233950A

CN113233950A - Method for preparing methyl cyclopentene from cyclohexene

Info

Publication number: CN113233950A
Application number: CN202110559739.6A
Authority: CN
Inventors: 陈恩之; 苗迎彬; 赵风轩; 赵培朝; 郭正谦; 朱伸兵
Original assignee: Chongqing Huafeng New Material Research Institute Co ltd; Chongqing Huafeng Polyamide Co ltd; CHONGQING HUAFON CHEMICAL CO LTD
Current assignee: Chongqing Huafeng New Material Research Institute Co ltd; Chongqing Huafeng Polyamide Co ltd; CHONGQING HUAFON CHEMICAL CO LTD
Priority date: 2021-05-21
Filing date: 2021-05-21
Publication date: 2021-08-10

Abstract

A method for preparing methylcyclopentene from cyclohexene comprises the steps of taking cyclohexene as a raw material in a reactor, and carrying out isomerization reaction under the action of a molecular sieve catalyst at the reaction temperature of 100-160 ℃ and the reaction pressure of 0.3-0.8MPa to obtain a mixture containing methylcyclopentene. The method has the advantages of simple reaction route, cheap and easily-obtained used catalyst, mild reaction conditions, easy separation of reaction products, no generation of three wastes in the reaction process and high environmental friendliness on the basis of ensuring the conversion rate.

Description

Method for preparing methyl cyclopentene from cyclohexene

Technical Field

The invention relates to the field of chemical industry, in particular to a method for preparing methyl cyclopentene from cyclohexene.

Background

Methylcyclopentene is an organic compound and is a colorless transparent liquid at normal temperature and pressure. Mainly used as reagents and chemical synthesis raw materials.

The current industrial production of methylcyclopentene is mainly C in the refining industry₆Obtained by further catalytic reaction and rectification, has long process flow, expensive catalyst and complex reaction product.

Therefore, how to design a method for producing methylcyclopentene with simple process and mild reaction is an urgent problem to be solved by those skilled in the art.

Disclosure of Invention

The invention aims to provide a method for preparing methyl cyclopentene from cyclohexene, aiming at the defects of the prior art, the method has the advantages of simple reaction route, cheap and easily-obtained used catalyst, mild reaction conditions, easy separation of reaction products, no generation of three wastes in the reaction process and high environmental friendliness on the basis of ensuring the conversion rate.

The technical scheme of the invention is as follows: a method for preparing methyl cyclopentene from cyclohexene comprises the following steps: in a reactor, cyclohexene is used as a raw material, and under the action of a molecular sieve catalyst, a mixture containing methylcyclopentene is obtained through an isomerization reaction at a reaction temperature of 100-160 ℃ and a reaction pressure of 0.3-0.8 MPa.

Furthermore, the particle size of the molecular sieve catalyst is 0.5-10 μm, the Si/Al molar ratio of the molecular sieve catalyst is 10-50, and the filling coefficient of the catalyst in the reactor is 0.2-0.5.

Preferably, the particle size of the molecular sieve catalyst is 1-5um, the Si/Al molar ratio of the molecular sieve catalyst is 20-40, and the filling factor of the catalyst in the reactor is 0.25-0.4.

Furthermore, the feed inlet of the reactor is positioned in the middle of the side wall of the reactor, the discharge outlet of the reactor is positioned in the middle of the side wall of the reactor and above the feed inlet, and a stirring device is arranged in the reactor.

Further, discharging the obtained mixture containing the methylcyclopentene to a rectifying tower, and carrying out reduced pressure distillation to obtain the methylcyclopentene at the top of the tower, wherein the temperature of the top of the rectifying tower is 35-55 ℃, the temperature of the bottom of the rectifying tower is 60-80 ℃, and the reflux ratio of the rectifying tower is 10-20.

Further, the bottom liquid of the rectifying tower returns to the reactor.

Preferably, the reaction temperature is 110-130 ℃, and the reaction pressure is 0.4-0.6 MPa.

Adopt above-mentioned technical scheme to have following beneficial effect:

1. the invention utilizes the cyclohexene as the raw material to carry out isomerization reaction under the action of the molecular sieve catalyst to obtain the methylcyclopentene, the reaction route is simple, the catalyst is cheap and easy to obtain, the conversion rate of the cyclohexene can reach 10 percent, the reaction condition is mild, the obtained mixture is simple and convenient to separate, and three wastes are not generated in the reaction process.

2. The preparation method of the invention controls the reaction temperature at 100-. If the temperature is lower than 100 ℃, the reaction conversion rate is obviously reduced, even the reaction is not reacted. If the temperature is above 160 ℃, the reaction will tend to bimolecular autopolymerization of cyclohexene rather than molecular rearrangement. The reaction is carried out by controlling the particle size of the molecular sieve catalyst to be 0.5-10 μm, the Si/Al molar ratio of the molecular sieve catalyst to be 10-50, and the filling coefficient of the catalyst in a reactor to be 0.2-0.5, wherein if the particle size of the catalyst is too small, the catalyst is not easy to separate, the loss is large, and the particle size is too large, so that the specific surface area of the catalyst is reduced, and the reaction conversion rate is influenced. The Si/Al molar ratio is also an important parameter which directly influences the conversion activity of the catalyst, and too high or too low results in a reduction in the conversion. The catalyst solid is a place where cyclohexene molecule rearrangement occurs, the reaction conversion rate is reduced due to an excessively small filling coefficient, the separation of the catalyst is influenced due to an excessively large filling coefficient, the loss is caused, the side reaction is increased, and the product yield is influenced.

3. The preparation method is characterized in that the feed inlet of the reactor is positioned below the discharge outlet, so that the repeated contact of the cyclohexene serving as the raw material and the catalyst is facilitated. The reactor is internally provided with stirring, which is beneficial to the directional flow of a reaction system. A solid-liquid separation structure is arranged in the reactor, the catalyst solid is sunk by utilizing the specific gravity difference, and the reaction product floats upwards to realize solid-liquid separation. The separated catalyst solid continuously returns to the central area of the reactor to participate in the reaction, and the separated reaction product flows out from the upper discharge port and enters the rectifying tower through pressure difference.

4. The mixture containing the methylcyclopentene prepared in the reactor is discharged to a rectifying tower, the target product in the mixture is separated, and the tower bottoms mainly comprise unreacted cyclohexene and the molecular sieve catalyst and return to the reactor for reuse, so that the utilization rate of the cyclohexene and the molecular sieve catalyst is effectively improved, and the cost of producing the methylcyclopentene by enterprises is reduced.

The following is a further description with reference to specific examples.

Detailed Description

Example 1

Adding cyclohexene (cyclohexene purity 99 wt%) and molecular sieve catalyst (volume concentration controlled at 0.25) into cyclohexene reactor, wherein the internal space of the cyclohexene reactor is 200m³The reaction temperature is controlled at 110-112 ℃, the pressure is controlled at 0.4-0.42MPa, and the cyclohexene feeding flow is controlled at 100-105m³And/h, carrying out molecular rearrangement on the cyclohexene to obtain a mixture containing the methylcyclopentene.

Discharging the obtained mixture into a rectifying tower, controlling the tower top temperature of the rectifying tower to be 35-37 ℃, the tower bottom temperature to be 60-63 ℃ and the reflux ratio to be 10, separating to obtain a methyl cyclopentene target product with the flow rate of 9-9.5m³The purity is 93-94 percent.

Example 2

Adding cyclohexene (cyclohexene purity 99 wt%) and molecular sieve catalyst (volume concentration controlled at 0.3) into cyclohexene reactor, wherein the internal space of the cyclohexene reactor is 200m³The reaction temperature is controlled at 121 ℃ and the pressure is controlled at 0.5-0.52MPa, and the flow of the cyclohexene feed is controlled at 140-143m³And/h, carrying out molecular rearrangement on the cyclohexene to obtain a mixture containing the methylcyclopentene.

Discharging the obtained mixture into a rectifying tower, controlling the tower top temperature of the rectifying tower to be 45-47 ℃, the tower bottom temperature of the rectifying tower to be 70-72 ℃ and the reflux ratio of 15, separating to obtain a methyl cyclopentene target product with the flow rate of 14-14.8m³The purity is 94-95%.

Example 3

Adding cyclohexene (cyclohexene purity 99 wt%) and molecular sieve catalyst (volume concentration controlled at 0.35) into cyclohexene reactor, wherein the internal space of the cyclohexene reactor is 200m³The reaction temperature is controlled to 130-³And/h, carrying out molecular rearrangement on the cyclohexene to obtain a mixture containing the methylcyclopentene.

Discharging the obtained mixture into a rectifying tower, controlling the tower top temperature of the rectifying tower to be 53-55 ℃, the tower bottom temperature to be 79-81 ℃ and the reflux ratio to be 20, separating to obtain a methyl cyclopentene target product with the flow rate of 18-18.2m³The purity is 94-95%.

Claims

1. A method for preparing methylcyclopentene from cyclohexene is characterized by comprising the following steps:

in a reactor, cyclohexene is used as a raw material, and under the action of a molecular sieve catalyst, a mixture containing methylcyclopentene is obtained through an isomerization reaction at a reaction temperature of 100-160 ℃ and a reaction pressure of 0.3-0.8 MPa.

2. The process of claim 1, wherein the molecular sieve catalyst has a particle size of 0.5 to 10 μm, a molecular sieve catalyst Si/Al molar ratio of 10 to 50, and a catalyst packing factor in the reactor of 0.2 to 0.5.

3. The process of claim 2, wherein the molecular sieve catalyst has a particle size of 1 to 5um, a molecular sieve catalyst Si/Al molar ratio of 20 to 40, and a catalyst loading factor in the reactor of 0.25 to 0.4.

4. The method according to claim 1, wherein the feed inlet of the reactor is positioned in the middle of the side wall of the reactor, the discharge outlet of the reactor is positioned in the middle of the side wall of the reactor and above the feed inlet, and a stirring device is arranged in the reactor.

5. The method as claimed in claim 1, wherein the obtained mixture containing methylcyclopentene is discharged to a rectifying tower, and subjected to reduced pressure distillation to obtain methylcyclopentene at the top of the tower, wherein the top temperature of the rectifying tower is 35-55 ℃, the bottom temperature of the rectifying tower is 60-80 ℃, and the reflux ratio of the rectifying tower is 10-20.

6. The method of claim 5, wherein bottoms from the rectification column are returned to the reactor.

7. The method as claimed in claim 1, wherein the reaction temperature is 110 ℃ and 130 ℃, and the reaction pressure is 0.4-0.6 MPa.