Preparation method of tert-butyl alcohol

Abstract

The invention discloses a preparation method of tert-butyl alcohol, and relates to the technical field of chemical raw materials. The method comprises the following steps: pretreatment of a catalyst: activating the solid acid catalyst to remove possible impurities and moisture so as to improve the activity and selectivity of the catalyst; hydration reaction: adding the pretreated catalyst into a reaction tower, introducing isobutene gas and water, stirring, and carrying out hydration reaction under the action of the catalyst; and separation and purification: the reacted mixture enters a separator, tert-butyl alcohol and the raw material are separated out, the unreacted raw material isobutene is circulated back to the reaction kettle to continue to participate in the reaction, the separated crude tert-butyl alcohol product enters a rectifying tower to be rectified and purified, and the tert-butyl alcohol product is obtained. Compared with a traditional liquid acid catalyst, the solid acid catalyst has the advantages of being easy to separate, capable of being repeatedly used, small in corrosion to equipment and the like.

Description

Technical Field

[0001] The invention relates to the technical field of chemical raw materials, in particular to a method for preparing tert-butyl alcohol. Background Art

[0002] Tert-butyl alcohol has good solubility in certain organic solvents and can be used as a solvent in industries such as coatings, paints, and inks. It is also an important raw material for synthesizing drugs and spices. Adding it to gasoline can increase the octane number of gasoline and enhance the anti-knock performance of gasoline. Hydration is an important way to prepare tert-butyl alcohol, which is divided into direct hydration and sulfuric acid hydration. However, direct hydration usually has problems such as low conversion rate and slow reaction rate, and sulfuric acid hydration can cause serious environmental pollution and corrode equipment. Therefore, it is necessary to develop a more advantageous hydration method. Summary of the invention

[0003] In order to solve the above problems, that is, to solve the problems raised by the above background technology, the present invention proposes a method for preparing tert-butyl alcohol, and the specific technical scheme is as follows:

[0004] A method for preparing tert-butyl alcohol, comprising the following steps:

[0005] Catalyst pretreatment: Activate the solid acid catalyst to remove possible impurities and moisture, and improve the activity and selectivity of the catalyst;

[0006] Hydration reaction: add the pretreated catalyst to the reaction mixture, introduce isobutylene gas and water, stir, and carry out hydration reaction under the action of the catalyst;

[0007] Separation and purification: The mixture after the reaction enters the separator to separate tert-butanol and the raw material. The unreacted raw material isobutylene is recycled back to the reactor to continue to participate in the reaction. The separated crude tert-butanol enters the distillation tower for distillation and purification to obtain tert-butanol product.

[0008] The catalyst pretreatment step is specifically as follows: selecting a suitable solid acid catalyst, specifically a sulfonic acid type ion exchange resin, placing the catalyst in an oven, and drying it at 100-150°C to remove moisture and adsorbed impurities on the catalyst surface, and further activating the dried catalyst, and purging it with nitrogen or hydrogen at 200-300°C to remove residual organic matter and impurities inside the catalyst.

[0009] The hydration reaction steps are specifically as follows: adding the pretreated solid acid catalyst into a reactor, introducing isobutylene gas and deionized water into the reactor, wherein the molar ratio of isobutylene to water is 1:1-5, stirring for 1 hour at 50-150°C and 0.5-5MPa. During the reaction, the reaction progress can be monitored in real time by online monitoring equipment, and the reaction conditions can be adjusted in time.

[0010] The separation and purification steps are specifically as follows: discharging the reaction mixture from the reactor, using a polypropylene membrane to utilize the selective permeation effect of the membrane to separate tert-butanol from unreacted isobutylene and water, and sending the separated crude tert-butanol product to a distillation tower for distillation and purification. During the distillation process, unreacted isobutylene and water are discharged from the top of the tower and returned to the hydration reaction step to continue to participate in the reaction, and the heavy components are discharged from the bottom of the tower, and the tert-butanol product is collected from an appropriate position in the middle of the tower.

[0011] In the distillation tower, the number of plates is 35, the reflux ratio is set to 3, the feed position is at 2 / 3 of the number of plates, the top temperature is controlled at 40-60°C, and the bottom temperature is controlled at 100-130°C.

[0012] The beneficial technical effects of the present invention are as follows: the solid acid catalyst has the advantages of easy separation, reusability, low corrosion to equipment, etc. compared with the traditional liquid acid catalyst; the reaction conditions are relatively mild, which reduces energy consumption and equipment investment costs; and the yield and purity of tert-butyl alcohol are improved by optimizing the process flow. DETAILED DESCRIPTION

[0013] The preferred embodiments of the present invention are described below. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0014] A method for preparing tert-butyl alcohol, comprising the following steps:

[0015] Catalyst pretreatment step: select a suitable solid acid catalyst, specifically a sulfonic acid type ion exchange resin, place the catalyst in an oven, dry it at 100-150°C to remove moisture and adsorbed impurities on the catalyst surface, and further activate the dried catalyst by purging it with nitrogen or hydrogen at 200-300°C to remove residual organic matter and impurities inside the catalyst.

[0016] Hydration reaction step: adding the pretreated solid acid catalyst into a reactor, introducing isobutylene gas and deionized water into the reactor, wherein the molar ratio of isobutylene to water is 1:1-5, stirring for 1 hour at 50-150°C and 0.5-5MPa. During the reaction, the reaction progress can be monitored in real time by online monitoring equipment, and the reaction conditions can be adjusted in time.

[0017] Separation and purification steps: the reaction mixture is discharged from the reactor, and the tert-butanol is separated from the unreacted isobutylene and water using a polypropylene membrane by utilizing the selective permeation effect of the membrane. The separated crude tert-butanol is sent to a distillation tower for distillation and purification. During the distillation process, the unreacted isobutylene and water are discharged from the top of the tower and returned to the hydration reaction step to continue the reaction. The heavy components are discharged from the bottom of the tower, and the tert-butanol product is collected from an appropriate position in the middle of the tower.

[0018] In the distillation tower, the number of plates is 35, the reflux ratio is set to 3, the feed position is at 2 / 3 of the number of plates, the top temperature is controlled at 40-60°C, and the bottom temperature is controlled at 100-130°C.

[0019] The yield of tert-butyl alcohol produced by the above method is increased to 92-95% compared with the 80-90% yield of the existing common hydration method or sulfuric acid hydration method, and the purity is increased from the existing 95-97% to 98-99%. It can be seen that the tert-butyl alcohol produced by the method of the present invention is superior to the existing hydration method in terms of purity and yield.

[0020] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0021] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments, but it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A method for preparing tert-butyl alcohol, characterized in that: The method comprises the following steps: Catalyst pretreatment: Activate the solid acid catalyst to remove possible impurities and moisture, and improve the activity and selectivity of the catalyst; Hydration reaction: add the pretreated catalyst to the reaction mixture, introduce isobutylene gas and water, stir, and carry out hydration reaction under the action of the catalyst; Separation and purification: The mixture after the reaction enters the separator to separate tert-butanol and the raw material. The unreacted raw material isobutylene is recycled back to the reactor to continue to participate in the reaction. The separated crude tert-butanol enters the distillation tower for distillation and purification to obtain tert-butanol product.

2. The method for preparing tert-butyl alcohol according to claim 1, wherein: The catalyst pretreatment step is specifically as follows: selecting a suitable solid acid catalyst, specifically a sulfonic acid type ion exchange resin, placing the catalyst in an oven, and drying it at 100-150°C to remove moisture and adsorbed impurities on the catalyst surface, and further activating the dried catalyst, and purging it with nitrogen or hydrogen at 200-300°C to remove residual organic matter and impurities inside the catalyst.

3. The method for preparing tert-butyl alcohol according to claim 1, wherein: The hydration reaction steps are specifically as follows: adding the pretreated solid acid catalyst into a reactor, introducing isobutylene gas and deionized water into the reactor, wherein the molar ratio of isobutylene to water is 1:1-5, stirring for 1 hour at 50-150°C and 0.5-5MPa. During the reaction, the reaction progress can be monitored in real time by online monitoring equipment, and the reaction conditions can be adjusted in time.

4. The method for preparing tert-butyl alcohol according to claim 1, wherein: The separation and purification steps are specifically as follows: discharging the reaction mixture from the reactor, using a polypropylene membrane to utilize the selective permeation effect of the membrane to separate tert-butanol from unreacted isobutylene and water, and sending the separated crude tert-butanol product to a distillation tower for distillation and purification. During the distillation process, unreacted isobutylene and water are discharged from the top of the tower and returned to the hydration reaction step to continue to participate in the reaction, and the heavy components are discharged from the bottom of the tower, and the tert-butanol product is collected from an appropriate position in the middle of the tower.

5. A method for preparing tert-butyl alcohol according to claim 4, characterized in that: In the distillation tower, the number of plates is 35, the reflux ratio is set to 3, the feed position is at 2 / 3 of the number of plates, the top temperature is controlled at 40-60°C, and the bottom temperature is controlled at 100-130°C.