CN110483244B - A kind of preparation method of tert-butanol - Google Patents

Abstract

The invention discloses a method for preparing tert-butyl alcohol, which comprises the steps of taking isobutane and oxygen as reaction raw materials, adding a certain amount of free radical initiator and solvent, controlling the reaction temperature to be 50-90 ℃, controlling the reaction pressure to be 0.5-1.5 MPa, and selectively oxidizing under the catalysis of hexatomic bimetallic porphyrin to prepare the tert-butyl alcohol. The active center of the catalyst is selected from one of iron, cobalt, nickel, copper or zinc. The invention has the advantages of mild reaction conditions, rich raw material sources, simple process and high conversion rate and selectivity.

Description

A kind of preparation method of tert-butanol

technical field

The invention relates to a method for preparing tert-butanol, in particular to a method for preparing tert-butanol by bimetalloporphyrin biomimetic catalytic isobutane selective oxidation.

Background technique

Tert-butanol, also known as 2-methyl-2-propanol, is a colorless transparent liquid or colorless crystal at room temperature, with a camphor-like odor, and has a wide range of uses. It can be used as fuel additive, raw material for the production of tert-butyl compound alkylation, as organic synthesis intermediate for the synthesis of drugs and fragrances, and can replace n-butanol as a solvent for coatings and medicines. The preparation of tert-butanol mainly includes isobutene hydration and isobutane oxidation.

The preparation of tert-butanol by isobutene hydration is dominated by ion exchange resins, ionic liquids or solid acids as catalysts. The disadvantage of the direct hydration method is that the miscibility of isobutene with water is poor, so the conversion rate is low. Although the sulfuric acid hydration method can obtain high yield of tert-butanol, it has problems such as large pollution, serious equipment corrosion, and many industrial wastes, and has been gradually eliminated at present.

Isobutane is one of the main components in the C4 fraction of petroleum cracking gas, and it has abundant sources. The direct oxidation of isobutane to prepare tert-butanol has attracted much attention. US Patent US 2845461 discloses a method for preparing tert-butanol by non-catalytic liquid-phase oxidation of isobutane. Under the reaction pressure of 3.4-4.8MPa and the reaction temperature of 100-150°C, the conversion rate of isobutane is directly oxidized by molecular oxygen. It can reach 20-35%, and the selectivity of tert-butanol is 15-20%. US Patent No. 4,404,406 discloses that isobutane has a conversion rate of 10-25% without catalytic oxidation of isobutane at temperatures above 140° C., and a selectivity of tert-butanol of 10-60%. These methods all need to be carried out under high temperature and high pressure, and the selectivity of tert-butanol is low.

Chinese patent CN 102391167 discloses a method for preparing tert-butanol by oxidizing isobutane with N-hydroxyphthalimide (NHPI) or its derivative as a catalyst. The oxygen source is molecular oxygen, the reaction temperature is 65～85℃, the reaction time is 5～7h, the conversion rate of isobutane is 4～42%, and the selectivity of tert-butanol is only 60%. The reaction conditions of this method are mild, but the selectivity of tert-butanol is low and the amount of catalyst is large. Chinese patent CN 104402675 discloses a method for preparing tert-butanol by biomimetic catalytic oxidation. The method has high isobutane conversion and tert-butanol selectivity, and the reaction conditions are mild. Additional metal salts are added as co-catalysts, resulting in complex products in the reaction system, and insoluble metal salts are easily coked during industrial production, causing pipeline blockage.

Therefore, it is of great practical significance and application prospect to develop a process method for preparing tert-butanol by catalytic oxidation of isobutane with mild reaction conditions, green and high efficiency.

SUMMARY OF THE INVENTION

In order to overcome the defects existing in the above-mentioned prior art, the object of the present invention is to provide a method for preparing tert-butanol by efficiently catalyzing and oxidizing isobutane with bimetalloporphyrin.

In order to achieve the purpose of the invention, the adopted technical scheme is:

A preparation method of tert-butanol, using isobutane and oxygen as reaction raw materials, adding a free radical initiator and a solvent, controlling the reaction temperature to be 50-90 DEG C, and the reaction pressure to be 0.5-1.5MPa, in the general formula (I) The selective oxidation of tert-butanol under the catalysis of structural bimetalloporphyrin;

M in general formula (1) is metal atom Fe, Co, Ni, Cu or Zn, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are all selected from hydrogen, halogen, nitro, alkyl, alkoxy group, hydroxyl, carboxyl or sulfonic acid group.

Preferably, in the above-mentioned preparation method of tert-butanol, the free radical initiator is one of N-hydroxyphthalimide (NHPI) or its derivatives.

Preferably, in the above-mentioned preparation method of tert-butanol, the solvent is one selected from dichloromethane, 1,2-dichloroethane, ethyl acetate, acetonitrile, benzonitrile or acetic acid.

Preferably, in the above-mentioned preparation method of tert-butanol, the amount of the catalyst is 10-50 ppm, the amount of the free radical initiator is 0.5-4 mol% of the raw material, the reaction temperature is 50-90° C., and the reaction pressure is 0.5-1.5 MPa.

Compared with the prior art, the present invention has the following beneficial effects:

1. The present invention has high reaction efficiency, high product selectivity, mild reaction conditions and low energy consumption.

2. The present invention adopts binuclear metalloporphyrin as a catalyst, which avoids the problems of acid catalyst corrosion equipment and environmental pollution in the isobutene hydration method.

3. The dinuclear porphyrin used in the present invention has higher catalytic activity than traditional porphyrins, and does not need to add metal salts as cocatalysts.

4. In the present invention, the catalyst is uniformly dissolved in the solvent, and a free radical initiator is added to make isobutane and oxygen catalyzed and oxidized under the action of the catalyst to generate tert-butanol. Under various reaction systems of the present invention, the yield and selectivity of tert-butanol are high, the product is easy to separate, the amount of catalyst and free radical initiator is small, the process is simple, green and safe, and has good industrial application prospects.

Detailed ways

The present invention will be further described below with reference to the embodiments, but the protection scope of the present invention is not limited to the scope represented by the embodiments.

Example 1

_{In a} 100ml autoclave, add _{25ml of 1,2-} 1,2- In dichloroethane, 0.3 mmol of free radical initiator NHPI was added, 20 mmol of isobutane and 1 MPa of O ₂ were charged, and the reaction was carried out at 60° C. for 6 h. Detected by gas chromatography, the conversion rate of isobutane was 50%, and the selectivity of tert-butanol was 75%.

Example 2

In a 100ml autoclave, add 25ml of dichloromethane containing 30ppm of metalloporphyrin (M=Co, R ₃ =F, R ₁ =R ₂ =R ₄ =R ₅ =H) with a structure of general formula (1), 0.2 mmol of free radical initiator NHPI was added, 20 mmol of isobutane and 1.5 MPa of O ₂ were charged, and the reaction was carried out at 50° C. for 8 h. By gas chromatography, the conversion rate of isobutane was 32%, and the selectivity of tert-butanol was 81%.

Example 3

In a 100ml autoclave, 25ml of ethyl acetate containing 25ppm of metalloporphyrin (M=Fe, R ₃ =F, R ₁ =R ₂ =R ₄ =R ₅ =H) with the structure of general formula (1) was added, 0.4 mmol of free radical initiator NHPI was added, 20 mmol of isobutane and 1 MPa of O ₂ were charged, and the reaction was carried out at 65° C. for 7 h. Detected by gas chromatography, the conversion rate of isobutane was 41%, and the selectivity of tert-butanol was 79%.

Example 4

In a 100ml autoclave, add 25ml of acetonitrile containing 30ppm of metalloporphyrin (M=Ni, R ₁ =R ₂ =R ₃ =R ₄ =R ₅ =F) with a structure of general formula (1), add 0.2mmol of acetonitrile The free radical initiator NHPI was charged with 20 mmol of isobutane and 0.7 MPa of O ₂ , and the reaction was carried out at 80 °C for 7 h. Detected by gas chromatography, the conversion rate of isobutane was 60%, and the selectivity of tert-butanol was 72%.

Example 5

_{In a} 100ml autoclave, add _{25ml of 1,2-} 1,2- In dichloroethane, 0.2 mmol of free radical initiator NHPI was added, 20 mmol of isobutane and 1 MPa of O ₂ were charged, and the reaction was carried out at 60° C. for 6 h. Detected by gas chromatography, the conversion rate of isobutane was 60%, and the selectivity of tert-butanol was 84%.

Example 6

In a 100ml autoclave, add 25ml of benzonitrile containing 35ppm of metalloporphyrin (M=Cu, R ₃ =F, R ₁ =R ₂ =R ₄ =R ₅ =H) with the structure of general formula (1), 0.2 mmol of free radical initiator NHPI was added, 20 mmol of isobutane and 1 Mpa of O ₂ were charged, and the reaction was carried out at 75° C. for 8 h. Detected by gas chromatography, the conversion rate of isobutane was 75%, and the selectivity of tert-butanol was 89%.

Example 7

In a 100 ml autoclave, 25 ml of acetonitrile containing 35 ppm of metalloporphyrin (M=Cu, R ₁ =R ₂ =R ₃ =R ₄ =R ₅ =F) with the structure of general formula (1) was added, and 0.2 mmol of acetonitrile was added. The free radical initiator NHPI was charged with 20 mmol of isobutane and 0.8 Mpa of O ₂ , and the reaction was carried out at 90° C. for 7 h. Detected by gas chromatography, the conversion rate of isobutane was 85%, and the selectivity of tert-butanol was 82%.

Example 8

In a 100ml autoclave, add 25ml of acetic acid containing 50ppm of metalloporphyrin (M=Cu, R ₃ =NO ₂ , R ₁ =R ₂ =R ₄ =R ₅ =H) with a structure of general formula (1), add 0.4mmol of free radical initiator NHPI was charged with 20mmol of isobutane and 1Mpa of O ₂ , and the reaction was carried out at 70°C for 10h. Detected by gas chromatography, the conversion rate of isobutane was 51%, and the selectivity of tert-butanol was 72%.

Example 9

In a 100ml autoclave, 25ml of 1,2-dichloromethane containing 40ppm of metalloporphyrin (M=Zn, R ₁ =R ₂ =R ₃ =R ₄ =R ₅ =F) with the structure of general formula (1) was added Ethane was added with 0.2 mmol of free radical initiator NHPI, charged with 20 mmol of isobutane and 1.5 Mpa of O ₂ , and reacted at 80° C. for 8 h. By gas chromatography, the conversion rate of isobutane was 42%, and the selectivity of tert-butanol was 76%.

Example 10

In a 100ml autoclave, 25ml of 1,2-dichloromethane containing 35ppm of metalloporphyrin (M=Co, R ₁ =R ₂ =R ₃ =R ₄ =R ₅ =F) with the structure of general formula (1) was added Ethane was added with 0.2 mmol of free radical initiator NHPI, charged with 20 mmol of isobutane and 1 Mpa of O ₂ , and reacted at 70° C. for 7 h. Detected by gas chromatography, the conversion rate of isobutane was 58%, and the selectivity of tert-butanol was 76%.

Example 11

In a 100ml autoclave, add 25ml of acetonitrile containing 15ppm of metalloporphyrin (M=Cu, R ₁ =R ₅ =F, R ₂ =R ₃ =R ₄ =H) with a structure of general formula (1), add 0.2 mmol of free radical initiator NHPI, charged with 20mmol of isobutane and 1.2Mpa of O ₂ , and reacted at 65°C for 9h. By gas chromatography, the conversion rate of isobutane was 62%, and the selectivity of tert-butanol was 79%.

Example 12

_{In a} 100ml autoclave, add _{25ml of 1,2-} 1,2- In dichloroethane, 0.4 mmol of free radical initiator NHPI was added, 20 mmol of isobutane and 1.2 Mpa of O ₂ were charged, and the reaction was carried out at 80° C. for 6 h. By gas chromatography, the conversion rate of isobutane was 64%, and the selectivity of tert-butanol was 81%.

Claims (6)

1. The preparation method of the tertiary butanol is characterized in that isobutane and oxygen are used as reaction raw materials, a free radical initiator and a solvent are added, the reaction temperature is controlled to be 50-90 ℃, the reaction pressure is 0.5-1.5 MPa, and the tertiary butanol is prepared by selective oxidation under the catalysis of bimetallic porphyrin with a structure shown in a general formula (I);

m in the general formula (I) is a metal atom Fe, Co, Ni, Cu or Zn, R₁、R₂、R₃、R₄And R₅Are all selected from hydrogen and halogen;

the free radical initiator is selected from N-hydroxyphthalimide or one of derivatives thereof.

2. The method according to claim 1, wherein the solvent is one selected from the group consisting of dichloromethane, 1, 2-dichloroethane, ethyl acetate, acetonitrile, benzonitrile and acetic acid.

3. The preparation method of claim 1, wherein the amount of the bimetallic porphyrin catalyst is 10-50 ppm.

4. The method according to claim 1, wherein the amount of the radical initiator is 0.5 to 4 mol% based on the raw material.

5. The method according to claim 1, wherein the reaction temperature is 50 to 90 ℃.

6. The method according to claim 1, wherein the reaction pressure is 0.5 to 1.5 MPa.