CN102924271B - Method for producing tert-butyl ester compound by esterification, rectification and coupling of organic carboxylic acid and isobutene - Google Patents

Abstract

The invention discloses a method for producing tert-butyl ester compound through esterification reaction rectification of organic acid and isobutylene. The method is that organic acid and isobutene are continuously fed into the reaction distillation device coupled with the side reactor and the rectification tower according to a certain ratio, and the reacted material enters the rectification tower, and then enters the next-stage side reactor for esterification. Reaction: Under continuous and stable operating conditions, control the operating pressure of the rectification tower at 0.002-0.1 MPa. The esterification reaction temperature is 20-80°C, and the reaction pressure is 0.1-1.0 MPa. The process of the invention has the advantages of short process flow, independent operation conditions of side reactor and rectification tower, flexible control, high reaction conversion rate and selectivity, and the mass fraction of tert-butyl ester continuously discharged from the top of the tower reaches more than 99%.

Description

A kind of organic carboxylic acid and isobutylene esterification reaction rectification coupling production method of tert-butyl ester compound

technical field

The invention belongs to the field of chemical industry, and relates to a method for producing tert-butyl ester compounds by coupling organic carboxylic acid and isobutylene esterification reaction rectification.

Background technique

Tert-butyl ester compounds have some special properties due to the tert-butyl group with large steric hindrance effect. For example, tert-butyl acetate has excellent solubility, suitable evaporation rate, medium flash point and excellent cleaning efficiency. It is a kind of Low toxicity, environmentally friendly solvent; tert-butyl acrylate has excellent photostability due to its unique and highly active unsaturated double bond and tert-butyl group, which is obtained by self-polymerization or copolymerization with other monomers , weather resistance, water resistance, oil resistance, chemical resistance and other good chemical and physical properties, so it has a wide range of applications in coatings, leather, paper, adhesives, daily chemical products, etc.

Due to the large steric hindrance effect of tert-butanol, it is difficult to synthesize tert-butyl ester through esterification reaction using organic carboxylic acid and tert-butanol as raw materials, and isobutene has active double bonds, which can be directly added and esterified with organic carboxylic acid to synthesize tert-butyl ester. butyl ester. U.S. Patent No. 6,194,602 uses large-pore zeolite catalysts such as Zeolite Y to catalyze the reaction of isobutene and acetic acid to synthesize tert-butyl acetate. Tert-butanol is used as an improver for improving selectivity. When the reaction temperature is 60 ° C and the acid/ene ratio is 2:1, isobutene is converted The rate is 60%, and the selectivity of tert-butyl acetate is 77.2%.

U.S. Patent US6242640 uses large-pore zeolites such as Zeolite Y, Zeolite beta, and Zeolite X as catalysts to catalyze the reaction of isobutene and acrylic acid to prepare tert-butyl acrylate. The reaction pressure is maintained at 3.4 MPa, the reaction temperature is 40 ° C, and the acid/ene ratio is 7. : 1, the space velocity was 23hr ^-1 , and the conversion rate of isobutene reached 84%.

Since the esterification reaction of organic carboxylic acid and isobutene is limited by thermodynamic equilibrium, when the ratio of raw materials is reacted according to the ratio of stoichiometric coefficients, the conversion rate of the reaction is not high. Isobutylene contains active double bonds, and it is also prone to dimerization or multimerization when reacting with organic carboxylic acid esterification, resulting in low selectivity of organic ester products. Although the use of a large excess of organic carboxylic acid can make the polymerization of isobutylene seldom occur, but in order to recover a large amount of organic carboxylic acid, it needs to be separated by rectification and other methods, and the energy consumption is high. Reactive distillation technology can break the restriction of chemical reaction balance and improve conversion rate and selectivity. Reactive distillation is generally carried out in a rectification tower equipment, and the working conditions (such as temperature and pressure) of both reaction and rectification must be consistent. For the direct esterification of organic carboxylic acid and isobutene to synthesize tert-butyl ester, the reaction temperature is generally in the range of 25-60°C, while the raw materials and products of the esterification reaction have relatively high boiling points, such as the boiling point of acetic acid is 118°C, the boiling point of acetic acid is tert-butyl The boiling point of butyl ester is 98°C, and it is separated by rectification under normal pressure. The temperature in the tower is between 98°C and 118°C, and the temperature of reaction and rectification does not match. In addition, the esterification reaction of isobutene and some organic carboxylic acids needs to be carried out under pressure, while rectification is carried out under normal pressure or reduced pressure, and the pressure of reaction and rectification do not match. Therefore, the reactive distillation process carried out in a rectification column is not suitable for the esterification of organic carboxylic acid and isobutylene to produce tert-butyl esters.

Contents of the invention

The object of the present invention is to provide a kind of reactive rectification process of producing tert-butyl ester compound by the reaction of organic carboxylic acid and isobutene in the reactive rectification device mainly composed of rectification column and side reactor coupling.

The object of the present invention can be achieved through the following measures:

A method for coupling organic carboxylic acid and isobutylene esterification reaction rectification to produce tert-butyl esters, the method adopts a reactive rectification device mainly composed of a rectification tower and a side reactor coupled, and the rectification tower is composed of the following Above all, it is divided into a rectification tower reactive distillation zone and a rectification tower rectification zone. The rectification tower reactive distillation zone is connected and coupled with each side reactor through the inlet and outlet material pipelines, thereby forming the reactive rectification zone; The isobutene is continuously fed into each side reactor connected to the rectification tower, and the tower bottom material and organic carboxylic acid enter the first side reactor, and after esterification reaction with isobutene, they return to the rectification tower reaction rectification area. Catalysts are installed in each side reactor, and the materials in the tower kettle enter each side reactor in turn for esterification reaction, and then return to the reaction rectification area of the rectification tower; the esterification reaction product is processed in the rectification area of the rectification tower. Rectification, the resulting tert-butyl esters are discharged from the top of the tower; the operating pressure of the rectification tower is 0.002-0.1 MPa; the temperature in each side reactor is 20-80 ° C, and the pressure of the esterification reaction is controlled at 0.1-0.1 MPa. 1.0Mpa, the reaction residence time is controlled at 1~15hr.

Wherein, the molar ratio of the total amount of isobutene to the organic carboxylic acid is preferably 1.0-1.5:1, more preferably 0.95-1.1:1.

Described organic carboxylic acid preferably contains the saturated or unsaturated fatty acid of 1～4 carbon atoms, or the fatty acid of halogen substituent; More preferably formic acid, acetic acid, propionic acid, acrylic acid, butyric acid, isobutyric acid, chloroacetic acid or bromoacetic acid.

The organic carboxylic acid can be fed continuously or intermittently, and the isobutylene can be fed continuously.

The incoming and outgoing materials of the side reactors are all connected to the rectification tower, and the number of side reactors is 1-10, preferably 3-4.

When the number of side reactors is multiple, the ratio of the isobutene fed into each side reactor to the total feed amount is 1-99%, preferably 20-80%.

The organic carboxylic acid can be fed continuously or intermittently, and the isobutylene can be fed continuously.

The side reactor can be a tank reactor or a fixed bed reactor. Commonly used catalysts for esterification, such as concentrated sulfuric acid, p-toluenesulfonic acid, ion exchange resins, molecular sieves and other homogeneous or heterogeneous catalysts, can be used in the present invention. The amount of catalyst in each side reactor is 1-50% of the mass of fresh organic carboxylic acid added, preferably 3-20%.

The number of trays in the rectification zone of the rectification tower is preferably 5-50, more preferably 10-30.

The number of trays in the reactive distillation zone of the rectification tower is preferably 2-20, more preferably 3-10.

The number of trays spaced between adjacent side reactors is preferably 1 to 5.

The number of separated trays on the rectification column for the incoming and outgoing materials connected to the side reactors is preferably 1 to 5.

In the material continuously extracted from the tower top of the reactive distillation device of the present invention, the mass fraction of tert-butyl ester compound can reach more than 99%, the mass fraction of organic carboxylic acid is lower than 0.5%, and the mass fraction of diisobutylene is lower than 1%. After the crude product is purified by rectification, the finished product of tert-butyl ester with a mass fraction of more than 99.5% can be obtained.

The advantages of the present invention are:

In the present invention, the side reactor is placed outside the rectification tower, and the feed material in the side reactor comes from the rectification tower, and enters the tray above it after being reacted, and the side reactor and the rectification tower are connected with each other And relatively independent. The operating conditions of the side reactor and the rectification tower can be the same or different, and can even be adjusted arbitrarily according to the needs of the process. The volume of the side reactor can be adjusted arbitrarily to achieve the best match between reaction capacity and separation capacity. The coupling process has the advantages of short process flow, easy control of reaction operation, high selectivity of tert-butyl ester compound, low production cost and high economic benefit.

Description of drawings

Figure 1 is a simplified process flow diagram for the coupled production of tert-butyl ester compounds by reactive distillation.

The labels in the figure are: 1-reaction rectification zone of rectification tower, 2-rectification zone of rectification tower, 3-vapor phase pipeline at the top of rectification tower, 4-top condenser of rectification tower, 5-rectification tower Connect the vacuum system pipeline, 6-rectification tower top reflux pipeline, 7-rectification tower top tert-butyl ester extraction pipeline, 8-return the liquid phase pipeline of the rectification tower from the nth side reactor, 9-from The liquid phase feed line from the rectification tower to the return of the nth side reactor, 10-the nth side reactor, 11-the isobutene feed line of the nth side reactor, 12-from the second side reactor Return to the liquid phase pipeline of the rectification tower, 13-the liquid phase feed line returned from the rectification tower to the second side reactor, 14-the second side reactor, 15-the isobutene feed line of the second side reactor Feed line, 16-return to the liquid phase line of the rectification tower from the first side reactor, the esterification reaction product and unreacted reactant are returned to the reaction rectification zone of the rectification tower through this pipeline, 17-from the rectification tower The liquid phase feed line returned from the tank to the first side reactor, through which the material in the tower tank enters the first side reactor, 18-the first side reactor, 19-the organic carboxylate of the first side reactor Acid feed line, 20-isobutene feed line of the first side reactor, 21-reboiler liquid phase circulation line of rectification column, 22-reboiler of rectification column, 23-reboiler of rectification column Boiler vapor phase recycle line.

Detailed ways

In order to further illustrate the present invention, illustrate by embodiment below.

The process flow of the following embodiments is all carried out according to the process flow shown in Figure 1 described in the description of the drawings.

Example 1:

In a rectification tower with an inner diameter of 1.0m and 30 trays, it is connected to two tank reactors with a volume of 5m ³ , in which the materials in the tower tank enter the first side reactor, and the materials at the outlet of the side reactor enter The fifth tray (the number of trays is counted from bottom to top); the material from the sixth rectification tray enters the second reactor, and the material from the outlet of the side reactor enters the eleventh tray, the rectification column and the side reactor The materials between the reactors are transported by pumps.

Each side reactor is equipped with 150kg ion exchange resin catalyst (D006 type produced by Hebei Kairui Chemical Co., Ltd.). The feed flow rate of acetic acid to the first side reactor is 5 kmol/h, and the feed flow rate of isobutene to the first and second side reactors is 3.5 and 1.5 kmol/h, respectively. The esterification reaction temperature is 35°C, the pressure of each side reactor is 0.15MPa, and the operating pressure of the rectification tower is 0.1MPa. The operating reflux ratio of the rectification tower is 1.5, the rectification reflux flow rate is 10 kmol/h, the output at the top of the tower is 5 kmol/h, and the flow rate from the rectification tower to the side reactor connected to it is 3 kmol/h . After the reactive distillation device is stabilized, the temperature at the top of the rectification tower is 97.5°C, the temperature at the bottom of the tower is 118°C, and the mass fractions of the liquid phase components extracted from the top of the tower are: 0.22% isobutene, 99.22% tert-butyl acetate, and 0.21% diisobutene , 0.35% acetic acid. The conversion rate of acetic acid was 99.32%, and the selectivity of tert-butyl acetate was 99.78%.

Example 2:

In a rectification tower with an inner diameter of 0.8m and 30 trays, it is connected with 4 tank reactors with a volume of 3m ³ , in which the materials in the tower tank enter the first side reactor, and the materials at the outlet of the side reactor enter The first tray (the number of trays is counted from bottom to top); the material from the second rectification tray enters the second side reactor, and the material from the outlet of the side reactor enters the third tray; from the fourth The material from the rectification tray enters the third side reactor, and the material from the outlet of the side reactor enters the fifth tray; the material from the sixth rectification tray enters the fourth side reactor, and the outlet of the side reactor The material enters the 7th tray; the material between the rectification column and the side reactor is pumped.

Each side reactor is equipped with 80kgY molecular sieve catalyst (Y molecular sieve produced by Lanzhou Petrochemical Catalyst Factory). The feed flow rate of acrylic acid to the first side reactor is 5 kmol/h, and the feed flow rate of isobutene to the first, second, third, and fourth side reactors is 2.0, 1.5, 1.0, and 0.5 kmol/h, respectively. The temperature of the esterification reaction is 20°C, the pressure of the side reactor is 0.2MPa, and the operating pressure of the rectification tower is 0.01MPa. The operating reflux ratio of the rectifying tower is 1.5, the rectifying reflux flow rate is 7.5kmol/h, the output at the top of the tower is 5kmol/h, and the flow rate from the rectifying tower to the side reactor connected to it is 3kmol/h h. After the reactive distillation device is stabilized, the temperature at the top of the rectification tower is 62°C, the temperature at the bottom of the tower is 98°C, and the mass fractions of the components extracted from the top of the tower are: 0.20% isobutene, 98.80% tert-butyl acrylate, 0.45% diisobutylene, acrylic acid 0.55%. The conversion rate of acrylic acid is 99.02%, and the selectivity of tert-butyl acrylate is 99.48%.

Example 3:

In a rectification tower with an inner diameter of 0.8m and 25 trays, it is connected to three tank reactors with a volume of 3m ³ , in which the materials in the tower tank enter the first side reactor, and the materials at the outlet of the side reactor enter The second tray (the number of trays is counted from bottom to top); the material from the third rectification tray enters the second side reactor, and the material from the outlet of the side reactor enters the fifth tray; from the sixth The material from the rectification tray enters the third side reactor, the outlet material of the side reactor enters the eighth tray, and the material between the rectification column and the side reactor is transported by a pump.

Each side reactor is equipped with 100kg HZSM-5 molecular sieve catalyst (the HZSM-5 molecular sieve produced by Nankai University Chemical Plant, the silicon-aluminum ratio is 38). The feed flow rate of chloroacetic acid to the first side reactor is 5 kmol/h, and the feed flow rate of isobutene to the first, second, and third side reactors is 3.75, 2.25, and 1.5 kmol/h, respectively. The esterification reaction temperature is 80°C, the side reactor pressure is 1.0MPa, and the operating pressure of the rectification tower is 0.005MPa. The operating reflux ratio of the rectifying tower is 1.5, the rectifying reflux flow rate is 7.5kmol/h, the output at the top of the tower is 5kmol/h, and the flow rate from the rectifying tower to the side reactor connected to it is 5kmol/h h. After the reactive distillation device is stabilized, the temperature at the top of the rectification tower is 67.6°C, and the temperature at the bottom of the tower is 106.2°C. The mass fractions of the components extracted from the top of the tower are: 45.65% isobutene, 84.05% tert-butyl chloroacetate, 0.18% diisobutene, Chloroacetic acid 0.12%. The conversion rate of chloroacetic acid is 99.77%, and the selectivity of tert-butyl chloroacetate is 99.71%.

Example 4:

In a rectification tower with an inner diameter of 1.0m and 50 trays, it is connected to 10 tank reactors with a volume of 3m ³ , in which the materials in the tower tank enter the first side reactor, and the materials at the outlet of the side reactor enter The first tray (the number of trays is counted from bottom to top); the material from the second rectification tray enters the second side reactor, and the material from the outlet of the side reactor enters the third tray; from the fourth The material from the rectification tray enters the third side reactor, the outlet material of the side reactor enters the fifth tray, and accordingly the material from the k+1 rectification tray enters the kth side reactor, The material from the outlet of the side reactor enters the kth tray, the material from the 11th rectification tray enters the 10th side reactor, the outlet material of the side reactor enters the 10th tray, the rectification column and the side reactor The material in between is conveyed by the pump.

Each side reactor is equipped with 40kg ion exchange resin catalyst (D006 type produced by Hebei Kairui Chemical Co., Ltd.). The feed flow rate of propionic acid to the first side reactor is 5 kmol/h, and the feed flow rate of isobutene to each side reactor is 0.5 kmol/h. The temperature of the esterification reaction is 40°C, the pressure of the side reactor is 0.3MPa, and the operating pressure of the rectification tower is 0.01MPa. The operating reflux ratio of the rectification tower is 2, the rectification reflux flow rate is 10 kmol/h, the output at the top of the tower is 5 kmol/h, and the flow rate from the rectification tower to the side reactor connected to it is 2 kmol/h . After the reactive distillation unit is stabilized, the temperature at the top of the rectification tower is 61°C, and the temperature at the bottom of the tower is 94°C. The mass fractions of the components extracted from the top of the tower are: isobutene 0.15%, tert-butyl propionate 99.34%, diisobutene 0.16%, Propionic acid 0.35%. The conversion rate of propionic acid was 99.38%, and the selectivity of tert-butyl propionate was 99.81%.

Claims (8)

1. the method for an organic carboxyl acid and iso-butylene esterification reaction rectification coupling production tert-butyl ester compound, it is characterized in that the method adopts the reaction and rectification device primarily of rectifying tower and side reaction device coupling composition, described rectifying tower is divided into distillation column reactor rectification zone and rectifying tower rectification zone from the bottom to top, described distillation column reactor rectification zone is passed through into and out of material pipe and each side reaction device butt coupling, thus forms reactive distillation district; Iso-butylene passes into each the side reaction device be connected with rectifying tower continuously, kettle material and organic carboxyl acid enter First side reaction device, after iso-butylene generation esterification, return the column plate of distillation column reactor rectification zone above it, and the interval stage number of turnover material on rectifying tower that side reaction device is connected is 1 ~ 5 piece; In each side reaction device, catalyzer is housed, kettle material enters each side reaction device successively and carries out esterification, returns distillation column reactor rectification zone after reaction; Between sides adjacent reactor, the stage number at interval is 1 ~ 5 piece; Esterification reaction product carries out rectifying in rectifying tower rectification zone, and gained tert-butyl ester compound is discharged by tower top; Described rectifying tower working pressure is at 0.002 ~ 0.1 MPa; Temperature in each side reaction device is at 20 ~ 80 DEG C, and esterification reaction pressure controls at 0.1 ~ 1.0 MPa; Wherein said iso-butylene total amount and the mol ratio of described organic carboxyl acid are 1.0 ~ 1.5:1; Described organic carboxyl acid is the saturated or unsaturated fatty acids containing 1 ~ 4 carbon atom, or the lipid acid of halogen substituent; The turnover material of side reaction device is all connected with rectifying tower, side reaction device number of units 2 ~ 10; Rectifying tower rectification zone stage number is at 5 ~ 50 pieces; Distillation column reactor rectification zone stage number is at 2 ~ 20 pieces.

2. method according to claim 1, is characterized in that the mol ratio of described iso-butylene total amount and described organic carboxyl acid is 0.95 ~ 1.1:1.

3. method according to claim 1, is characterized in that described organic carboxyl acid is formic acid, acetic acid, propionic acid, vinylformic acid, butyric acid, isopropylformic acid, Mono Chloro Acetic Acid or bromoacetic acid.

4. method according to claim 1, is characterized in that the turnover material of side reaction device is all connected with rectifying tower, side reaction device number of units 3 ~ 4.

5. method according to claim 4, it is 1 ~ 99% that the iso-butylene that it is characterized in that passing into each side reaction device accounts for the ratio always passing into total amount.

6. method according to claim 5, it is 20 ~ 80% that the iso-butylene that it is characterized in that passing into each side reaction device accounts for the ratio always passing into total amount.

7. method according to claim 1, is characterized in that rectifying tower rectification zone stage number is at 10 ~ 30 pieces.

8. method according to claim 1, is characterized in that distillation column reactor rectification zone stage number is at 3 ~ 10 pieces.