A process for the synthesis of 2,4,4-trimethyl-2-pentanol from diisobutene via esterification hydration

Abstract

The application provides a method for synthesizing 2,4,4-trimethyl-2-pentanol from diisobutene by esterification hydration, comprising the following steps: S1, esterification hydration reaction: diisobutene, organic acid and water are reacted in the presence of a catalyst; S2, separation and recovery: S3, hydrogenation reaction: 2,4,4-trimethyl-2-pentyl acetate recovered in step S2.5 is subjected to catalytic hydrogenation to generate a hydrogenation reaction liquid containing 2,4,4-trimethyl-2-pentanol and ethanol; S4, the hydrogenation reaction liquid obtained in step S3 is separated, and TMPOL is synthesized by using the above method with the organic acid as a medium, the single-pass conversion rate of diisobutene can reach 50%, and the selectivity reaches 99%. The process has the characteristics of high efficiency and high atom economy, and has great industrialization potential.

Description

Technical Field

[0001] This invention belongs to the field of organic chemical technology, specifically relating to an integrated process for synthesizing 2,4,4-trimethyl-2-pentanol (TMPOL) from diisobutylene, organic acids and water through esterification hydration, separation and hydrogenation steps. Background Technology

[0002] 2,4,4-Trimethyl-2-pentanol (TMPOL) is an important chemical intermediate and solvent. Traditional synthesis methods often suffer from problems such as cumbersome steps, low selectivity, high energy consumption, or environmental pollution. Diisobutylene (DIB), as an readily available chemical raw material, provides a new route for its synthesis. CN116986964A reports a method for producing diisobutylene from isobutylene. With the overcapacity of isobutylene, the development of downstream processes is urgent, but there are very few reports on downstream processes for diisobutylene.

[0003] Numerous publications and patents have reported on the production of alcohols from olefins, primarily through two routes: olefin esterification hydrogenation and olefin hydration. CN101293824A reports the preparation of tert-butyl acetate from acetic acid and n-butene. CN119098223A reports the preparation of methyl isononanoate from diisobutylene, CO, and methanol under catalysis. CN117164431A reports the preparation of cyclohexene alcohol from cyclohexene and water under catalysis. CN119285439A discloses a method for preparing tert-butanol from isobutylene hydration. While there are many patents on esterification hydrogenation and hydration, no reports have been found on methods for preparing 2,4,4-trimethyl-2-pentanol (TMPOL) from diisobutylene via esterification hydrogenation or hydration.

[0004] Analysis of the causes: As the alkyl chain length increases, the difficulty of olefin esterification and hydration increases significantly, leading to a sharp decline in conversion and selectivity. For olefins with increased side chains, low-temperature reactions only produce a small amount of tertiary esters and trace amounts of tertiary alcohols with extremely low conversion rates; high-temperature reactions mainly produce olefin polymers. The diisobutylene used in this invention has 8 carbon atoms and 3 methyl side chains, making it difficult to effectively synthesize the target product TMPOL through either direct esterification and hydrogenation or direct hydration. Previous exploratory experiments have confirmed this difficulty, and therefore, it is necessary to improve the existing process to overcome the above-mentioned defects. Summary of the Invention

[0005] This invention aims to address the shortcomings of existing technologies by providing an integrated process for the efficient synthesis of TMPOL from diisobutylene. Through innovative separation sequence design, this method achieves efficient recovery and recycling of reactants (diisobutylene and acetic acid) and completes the hydrogenation conversion of the byproduct TMPAC, thereby significantly improving the diisobutylene conversion rate and the overall selectivity of TMPOL, while reducing raw material consumption and waste emissions.

[0006] To achieve the above objectives, in a first aspect, this application provides a method for synthesizing 2,4,4-trimethyl-2-pentanol from diisobutylene via esterification and hydration, comprising the following steps: S1, Esterification and Hydration Reaction: In the presence of a catalyst, diisobutylene, organic acid and water are reacted to produce a reaction solution containing diisobutylene, organic acid, water, 2,4,4-trimethyl-2-pentanol, 2,4,4-trimethyl-2-pentyl acetate and byproducts. S2. Separation and Recycling: S2.1. The reaction solution obtained in step S1 is subjected to extractive distillation with water as the extractant. Diisobutylene is recovered from the top of the column and returned to step S1 for recycling. The first mixture is obtained from the bottom of the column. S2.2. The first mixture is subjected to azeotropic dehydration distillation to remove water using diisobutylene as an azeotropic agent, and the second mixture is obtained in the bottom of the column. S2.3. The second mixture is distilled to recover organic acids. The recovered organic acids are returned to step S1 for recycling, and a third mixture is obtained in the bottom of the column. S2.4. The third mixture is distilled to recover the 2,4,4-trimethyl-2-pentanol product, and the bottom of the distillation column yields a fourth mixture rich in 2,4,4-trimethyl-2-pentyl acetate. S2.5. The fourth mixture is subjected to distillation to recover 2,4,4-trimethyl-2-pentyl acetate, and 2,4,4-trimethyl-2-pentyl acetate is obtained at the top of the column; S3, Hydrogenation reaction: The 2,4,4-trimethyl-2-pentyl acetate recovered in step S2.5 is subjected to catalytic hydrogenation to generate a hydrogenation reaction solution containing 2,4,4-trimethyl-2-pentanol and ethanol. S4. Separate the hydrogenation reaction solution obtained in step S3 and recover ethanol and 2,4,4-trimethyl-2-pentanol.

[0007] Optionally, in step S1, the diisobutylene is 2,4,4-trimethyl-1-pentene or 2,4,4-trimethyl-2-pentene or a mixture of the two.

[0008] Optionally, in step S1, the organic acid includes one of acetic acid, formic acid, propionic acid, butyric acid, and benzoic acid.

[0009] Optionally, in step S1, the catalyst includes one of phosphoric acid, sulfuric acid, or a solid acid catalyst.

[0010] Optionally, in step S1, the reaction temperature is 0–100°C and the pressure is atmospheric pressure to 2.0 MPa.

[0011] Optionally, in step S1, the molar ratio of diisobutylene, organic acid and water is 1:1-20:1-20.

[0012] Optionally, in step S2.1, the mass ratio of the feed amount of extraction water to the feed amount of reaction liquid is 0.5 to 10:1.

[0013] Optionally, in step S2.1, a portion of the diisobutylene from the top of the extractive distillation column is returned to the esterification hydration reactor, and the other portion enters the azeotropic dehydration column; and a supplementary pipeline is provided on the diisobutylene pipeline entering the azeotropic dehydration column.

[0014] Optionally, in step S2.2, after the distillate from the top of the azeotropic dehydration distillation column is condensed and separated into layers, the oil phase is refluxed, part of the aqueous phase is returned to the extractive distillation column, and the remaining aqueous phase is discharged from the system.

[0015] Optionally, in step S3, the hydrogenation reaction temperature is 100–300°C and the hydrogen pressure is 2.0–8.0 MPa; the hydrogenation catalyst is a palladium-based, platinum-based, nickel-based, or copper-based catalyst.

[0016] Optionally, in step S4, the hydrogenation reaction liquid is separated by distillation, ethanol is recovered from the top of the column, and 2,4,4-trimethyl-2-pentanol is recovered from the bottom of the column.

[0017] The present invention provides a method for synthesizing 2,4,4-trimethyl-2-pentanol from diisobutylene via esterification and hydration. Compared with the prior art, its advantages are as follows: 1. High Conversion Rate and High Selectivity: Utilizing an esterification-hydration coupling method, water is the raw material for the core product, and acetic acid serves as the mediating raw material. Its key role is to overcome the steric hindrance and difficulty in direct hydration of diisobutylene, achieving high single-pass conversion rate and high selectivity for the conversion of diisobutylene to TMPOL. By recycling unreacted diisobutylene and acetic acid, and hydrogenating the intermediate product TMPAC to convert it into the target product, the overall conversion rate of diisobutylene can reach over 99%, and the selectivity for TMPOL can reach over 98%.

[0018] 2. Atom economy and resource recycling: A closed-loop cycle of the core raw materials diisobutylene and acetic acid has been achieved, the byproduct TMPAc has been efficiently converted into products, and ethanol has been recovered as a valuable co-product, which significantly improves atom economy and greatly reduces raw material costs.

[0019] 3. High separation efficiency: The combined separation strategy of "extractive distillation + azeotropic dehydration" effectively solves the separation problem of the diisobutylene-acetic acid-water homogeneous system with low energy consumption.

[0020] 4. High process integration: The process integrates esterification hydration, multi-stage distillation separation, hydrogenation reaction and product recycling into a continuous process flow, which is suitable for continuous industrial production and has stable and reliable operation. Attached Figure Description

[0021] Figure 1 This is a schematic diagram illustrating the reaction principle for synthesizing 2,4,4-trimethyl-2-pentanol from diisobutylene and acetic acid according to the present invention. Figure 2 This is a schematic diagram of the process for synthesizing 2,4,4-trimethyl-2-pentanol from diisobutylene. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present application will now be described in detail with reference to the embodiments.

[0024] Example 1 Reference Figure 1 and Figure 2 The process for implementing this invention is as follows: S1. Esterification and Hydration: A mixture of 2,4,4-trimethyl-1-pentene and 2,4,4-trimethyl-2-pentene (diisobutylene, molar ratio 1:1), acetic acid, and water (molar ratio 1:10:5) is continuously pumped into a reactor containing a phosphoric acid catalyst. The reaction is carried out at atmospheric pressure and the temperature is controlled at 40°C. The composition of the discharged reaction solution (mass fraction) is: approximately 4% diisobutylene, approximately 73% acetic acid, approximately 14% water, approximately 8% TMPOL, approximately 1% TMPAc, and approximately 0.01% PDIB. S2. Separation and Recovery: The reaction liquid enters the extractive distillation column, where extraction water (water to reaction liquid mass ratio 1:1) is added to the top. Diisobutylene (purity > 99%, water content < 0.5%) is collected from the top of the column and returned to the reactor after condensation. The bottom liquid of the extractive distillation column enters the azeotropic dehydration column. The diisobutylene-water azeotrope collected from the top of the azeotropic dehydration column condenses and separates into layers; the oil phase is refluxed, and the aqueous phase is discharged. The bottom liquid of the azeotropic dehydration column enters the acetic acid recovery column. Acetic acid (purity > 98%) is collected from the top of the acetic acid recovery column and returned to the reactor. The bottom liquid of the acetic acid recovery column enters the TMPOL recovery column. TMPOL product (purity > 99%) is collected from the top of the TMPOL recovery column, and the bottom liquid of the TMPOL recovery column enters the TMPAc recovery column. TMPAc (purity > 95%) is collected from the top of the TMPAc recovery column, and a small amount of tar is discharged from the bottom of the TMPAc recovery column. S3. Hydrogenation reaction: TMPAc and hydrogen (H2 / TMPAc molar ratio 10:1) are introduced into a fixed-bed hydrogenation reactor packed with Pd / C catalyst at a temperature of 150℃, a pressure of 5.0 MPa, and a space velocity of 1.0 h⁻¹. TMPAc conversion rate > 99.9%. S4. Product Separation: The hydrogenation product enters the ethanol recovery tower. Ethanol (purity > 99%) is collected from the top of the ethanol recovery tower, and TMPOL from the bottom of the tower is returned to the feed or product tank of the TMPOL recovery tower. In this embodiment, the total conversion rate of diisobutylene was 99.0%, and the total selectivity of TMPOL was 98.5%.

[0025] Example 2 Adjustments were made to the conditions of step S1: sulfuric acid was used as the catalyst, the reaction temperature was 50°C, the pressure was 0.5 MPa, and the molar ratio of diisobutylene, acetic acid, and water was 1:10:2.5. The extraction water ratio in step S2.1 was adjusted to 2:1. Step S3 used a Raney Ni catalyst, the temperature was 180°C, and the pressure was 3.0 MPa. The remaining steps were the same as in Example 1. The total conversion rate of diisobutylene was measured to be 98.8%, and the total selectivity of TMPOL was 98.1%.

[0026] Example 3 Adjusting the conditions for step S1: Using Dandong Mingzhu's DZH catalyst, the reaction temperature was 20℃, the pressure was atmospheric pressure, and the molar ratio of diisobutylene, propionic acid, and water was 1:6:3. In step S2.1, the extraction water ratio was adjusted to 2:1. In step S3, Ruihua copper-based catalyst was used, the temperature was 160℃, and the pressure was 2.0 MPa. The remaining steps were the same as in Example 1. The total conversion rate of diisobutylene was measured to be 97.5%, and the total selectivity of TMPOL was 98.2%.

[0027] Example 4 Adjustments to step S1 conditions: Dandong Mingzhu DA-330 catalyst was used, reaction temperature 30℃, pressure 0.5 MPa, and the molar ratio of diisobutylene, acetic acid, and water was 1:10:6. The extraction water ratio in step S2.1 was adjusted to 1:1. Step S3 used a Ni / Al2O3 catalyst, temperature 170℃, and pressure 3.0 MPa. The remaining steps were the same as in Example 1. The total conversion rate of diisobutylene was measured to be 98.5%, and the total selectivity of TMPOL was 98.5%.

[0028] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for synthesizing 2,4,4-trimethyl-2-pentanol from diisobutylene via esterification and hydration, characterized in that, Includes the following steps: S1, Esterification and Hydration Reaction: In the presence of a catalyst, diisobutylene, organic acid and water are reacted to produce a reaction solution containing diisobutylene, organic acid, water, 2,4,4-trimethyl-2-pentanol, 2,4,4-trimethyl-2-pentyl acetate and byproducts. S2. Separation and Recycling: S2.

1. The reaction solution obtained in step S1 is subjected to extractive distillation with water as the extractant. Diisobutylene is recovered from the top of the column and returned to step S1 for recycling. The first mixture is obtained from the bottom of the column. S2.

2. The first mixture is subjected to azeotropic dehydration distillation to remove water using diisobutylene as an azeotropic agent, and the second mixture is obtained in the bottom of the column. S2.

3. The second mixture is distilled to recover organic acids. The recovered organic acids are returned to step S1 for recycling, and a third mixture is obtained in the bottom of the column. S2.

4. The third mixture is distilled to recover the 2,4,4-trimethyl-2-pentanol product, and the bottom of the distillation column yields a fourth mixture rich in 2,4,4-trimethyl-2-pentyl acetate. S2.

5. The fourth mixture is subjected to distillation to recover 2,4,4-trimethyl-2-pentyl acetate, and 2,4,4-trimethyl-2-pentyl acetate is obtained at the top of the column; S3, Hydrogenation reaction: The 2,4,4-trimethyl-2-pentyl acetate recovered in step S2.5 is subjected to catalytic hydrogenation to generate a hydrogenation reaction solution containing 2,4,4-trimethyl-2-pentanol and ethanol. S4. Separate the hydrogenation reaction solution obtained in step S3 and recover ethanol and 2,4,4-trimethyl-2-pentanol.

2. The method for synthesizing 2,4,4-trimethyl-2-pentanol from diisobutylene via esterification and hydration as described in claim 1, characterized in that: In step S1, the diisobutylene is 2,4,4-trimethyl-1-pentene or 2,4,4-trimethyl-2-pentene or a mixture of the two.

3. The method for synthesizing 2,4,4-trimethyl-2-pentanol from diisobutylene via esterification and hydration as described in claim 1, characterized in that: In step S1, the organic acid includes one of acetic acid, formic acid, propionic acid, butyric acid, and benzoic acid.

4. The method for synthesizing 2,4,4-trimethyl-2-pentanol from diisobutylene via esterification and hydration as described in claim 1, characterized in that: In step S1, the catalyst includes one of phosphoric acid, sulfuric acid, or a solid acid catalyst.

5. The method for synthesizing 2,4,4-trimethyl-2-pentanol from diisobutylene via esterification and hydration as described in claim 1, characterized in that: In step S1, the reaction temperature is 0 to 100°C and the pressure is atmospheric pressure to 2.0 MPa.

6. The method for synthesizing 2,4,4-trimethyl-2-pentanol from diisobutylene via esterification and hydration as described in claim 1, characterized in that: In step S1, the molar ratio of diisobutylene, organic acid and water is 1:1~20:1~20.

7. The method for synthesizing 2,4,4-trimethyl-2-pentanol from diisobutylene via esterification and hydration as described in claim 1, characterized in that: In step S2.1, the mass ratio of the feed amount of extraction water to the feed amount of reaction liquid is 0.5 to 10:

1.

8. The method for synthesizing 2,4,4-trimethyl-2-pentanol from diisobutylene via esterification and hydration as described in claim 1, characterized in that: In step S2.1, part of the diisobutylene from the top of the extractive distillation column is returned to the esterification hydration reactor, and the other part enters the azeotropic dehydration column; and a supplementary pipeline is provided on the diisobutylene pipeline entering the azeotropic dehydration column.

9. The method for synthesizing 2,4,4-trimethyl-2-pentanol from diisobutylene via esterification and hydration as described in claim 1, characterized in that: In step S2.2, after the distillate from the top of the azeotropic dehydration distillation column is condensed and separated into layers, the oil phase is refluxed, part of the aqueous phase is returned to the extractive distillation column, and the remaining aqueous phase is discharged from the system.

10. The method for synthesizing 2,4,4-trimethyl-2-pentanol from diisobutylene via esterification and hydration as described in claim 1, characterized in that: In step S3, the hydrogenation reaction temperature is 100–300°C and the hydrogen pressure is 2.0–8.0 MPa; the hydrogenation catalyst is a palladium-based, platinum-based, nickel-based, or copper-based catalyst.

11. The method for synthesizing 2,4,4-trimethyl-2-pentanol from diisobutylene via esterification and hydration as described in claim 1, characterized in that: In step S4, the hydrogenation reaction liquid is separated by distillation, ethanol is recovered from the top of the column, and 2,4,4-trimethyl-2-pentanol is recovered from the bottom of the column.

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