JPH09110732A - Method for producing 2,3-dimethyl-2-butene - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extremely efficiently obtain 2,3-dimethyl-2-butene using a highly active catalyst obtained without carrying out a troublesome preparation step by using a heteropoly acid as a catalyst in isomerization of 2,3-dimethyl-1-butene. SOLUTION: 2,3-Dimethyl-1-butene(DMB-1) is isomerized using a heteropoly acid (preferably Keggin type heteropoly acids having a composition of the formula H2 SiW12 O40 ). The heteropoly acid may be used by baking the acid at 70-120 deg.C under reduced pressure or nitrogen gas. When the isomerization reaction is carried out by batch type, the reaction is preferably carried out at 20-150 deg.C using the heteropoly acid in an amount of 1-5wt.% based on DMB-1. In the case of communication type, the reaction is carried out by making the heteropoly acid packed in a reactor communicate with DMB-1. In this case, the reaction temperature is preferably -10 to 150 deg.C. The communication rate is usually 1-10h<-1> as superficial liquid velocity.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to 2,3-dimethyl-2-
The present invention relates to a method for producing butene (DMB-2), more specifically, a method for producing DMB-2 by isomerizing 2,3-dimethyl-1-butene (DMB-1).

[0002]

[Prior Art and Problems to be Solved by the Invention] DMB-2
Is an important compound as a basic intermediate for agricultural chemicals, pharmaceuticals, fragrances, cosmetics, etc., and is known to be produced by isomerizing DMB-1 using a catalyst. For example, Al as a catalyst
Method using Et ₃ / halogenated phenols
57-48094), a method using AlEt ₃ / 1,1,1,3,3,3-hexafluoroisopropanols (JP-A-62-209).
However, these methods have a problem in that the preparation of the catalyst is complicated because it is necessary to pay attention to deactivation of the catalyst due to heat generation and water during the preparation of the catalyst. In addition, a process such as extraction is required when separating the catalyst after the reaction. Furthermore, a method using sulfuric acid or sulfonic acids as a catalyst is also known (Japanese Patent Laid-Open No. 6-312945), but in this method, not only the problem that a neutralization treatment is necessary for separation of the catalyst after the reaction but also DMB- There was a problem that the selectivity from 1 to DMB-2 was not always satisfactory.

[0003]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that by using a specific catalyst called heteropolyacid as a catalyst,
It was found that a catalyst having high activity can be obtained without complicated preparation, and that DMB-1 to DMB-2 can be efficiently produced, and that the treatment of the catalyst after the reaction is easy, and further various The present invention has been completed with the addition of the consideration.

That is, the present invention isomerizes 2,3-dimethyl-1-butene (DMB-1) to give 2,3-dimethyl-2-butene (DMB-1).
The present invention provides an industrially excellent method for producing DMB-2, which comprises using a heteropolyacid as a catalyst for producing B-2).

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The DMB-1 used in the present invention is produced, for example, by dimerizing propylene (see, for example, JP-A-57 / 57).
-167932 publication). The catalyst used in the present invention is a heteropolyacid such as silicotungstic acid,
Examples thereof include silicomolybdic acid, phosphotungstic acid, phosphomolybdic acid and phosphotungsten molybdic acid.
Preferred are Keggin-type heteropolyacids, specifically H ₄ SiW ₁₂ O ₄₀ , H ₄ SiMo ₁₂ O ₄₀ , and H ₃ PW _12.
Examples thereof include compounds having a composition such as O ₄₀ , H ₃ PMo ₁₂ O ₄₀ or Cs _2.5 H _0.5 PW ₁₂ O ₄₀ , alkali metal salts thereof, ammonium salts thereof, and the like. These heteropolyacids can be used alone or as a mixture.

The heteropolyacids are usually calcined before use, and preferably calcined under reduced pressure or under nitrogen at 50 ° C to 150 ° C, preferably 70 ° C to 120 ° C.
The heteropoly acid can also be used by supporting it on activated carbon. Examples of the loading method include a method in which the heteropolyacids are mixed with a carrier such as activated carbon in water or alcohol, and then dried and calcined under reduced pressure or under nitrogen at 80 ° C to 120 ° C.

The method of the present invention is characterized by using the above-mentioned heteropolyacids as a catalyst, but this reaction can be carried out in either a batch system or a flow system.

In the case of a batch system, the reaction is carried out, for example, by mixing DMB-1 and the heteropolyacid with stirring. The amount of the heteropolyacids used is usually 0 with respect to DMB-1.
It is 5 to 10 wt%, preferably 1 to 5 wt%. The reaction temperature is generally 0 to 200 ° C, preferably 20 to 150 ° C. 200 ° C
The isomerization efficiency tends to decrease at a reaction temperature exceeding 0 ° C., and the reaction rate tends to decrease at a temperature lower than 0 ° C., which is not preferable.

On the other hand, in the case of the flow system, for example, the heteropolyacids are filled in a reaction tube and DMB-1 is circulated in the reaction tube. The reaction temperature is not particularly limited, but it is usually -20 to 150 ° C, preferably -10 to 150 ° C from the viewpoint of increasing the isomerization efficiency. The flow rate depends on the reaction conditions such as temperature, but it is usually about ¹ to 10 h ^{-1 in} terms of liquid superficial velocity.

In the present invention, the reaction may be carried out under pressure, if necessary, in either a batch system or a flow system. If necessary, a solvent inert to the reaction may coexist. Examples of such a solvent include aliphatic hydrocarbons such as heptane, octane, nonane, and decane, and aromatic hydrocarbons such as toluene and xylene.

In the present invention, the catalyst after the reaction can be easily separated from the reaction solution by an operation such as filtration in the case of a batch system. In the case of the flow type, since the flowed reaction liquid is obtained in a form separated from the catalyst, further separation operation of the catalyst is unnecessary. DMB-2 can be obtained by distilling off the solvent when a solvent is used,
If necessary, it can be purified by distillation.

[0012]

EFFECT OF THE INVENTION Thus, DMB-2 can be obtained. According to the present invention, in producing DMB-2 by isomerizing DMB-1,
By using heteropolyacids as a catalyst, a catalyst showing high activity can be obtained without requiring complicated preparation, and DM
B-2 can be produced extremely efficiently. Moreover, since the catalyst can be easily treated after the reaction, the present invention is advantageous as an industrial production method of DMB-2.

[0013]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

Example 1 0.3 g of silicotungstic acid (H ₄ SiW ₁₂ O ₄₀ ) calcined at 100 ° C. under reduced pressure for 2 hours was placed in a 100 ml autoclave, 10 g of DMB-1 was added, and the mixture was stirred at 50 ° C. for 6 hours. did. Then, the mixture was cooled to 0 ° C. and filtered to remove silicotungstic acid to obtain crude DMB-2. When analyzed by gas chromatography, the isomerization rate was 91.1% and the DMB-1,2 recovery rate was 98.7%. This was distilled to give DMB-2 (boiling point 72
˜74 ° C.) 7.9 g was obtained. The isomerization rate and DMB-1,2 recovery rate were calculated by the following formulas. Isomerization rate (%) = {DMB-2 amount / (DMB-1 amount + DMB-2 amount)} ×
100 DMB-1,2 Recovery rate (%) = {(DMB-1 amount + DMB-2 amount after reaction)
/ (Before reaction, amount of DMB-1 + amount of DMB-2)} × 100

Example 2 A silicotungstic acid (H ₄ SiW ₁₂ O ₄₀ ) firing time was set to 6
DMB-2 was obtained according to Example 1 except that the reaction temperature was changed to 40 ° C. and the reaction time was changed to 7 hours. Isomerization rate is 9
The yield was 2.2% and DMB-1,2 recovery rate was 97.2%.

Example 3 0.3 g of phosphomolybdic acid (H ₃ PMo ₁₂ O ₄₀ ) was used in place of 0.3 g of silicotungstic acid (H ₄ SiW ₁₂ O ₄₀ ), the reaction temperature was 150 ° C., and the reaction time was 4 DMB-2 was obtained according to Example 1 except that the time was changed. Isomerization rate is 84.2
%, DMB-1,2 recovery rate was 95.7%.

Example 4 DMB-2 was obtained according to Example 3 except that 0.3 g of phosphotungsten molybdic acid was used instead of 0.3 g of phosphomolybdic acid (H ₃ PMo ₁₂ O ₄₀ ). Isomerization rate is 80.6%, DM
The B-1,2 recovery rate was 89.0%.

Example 5 10 ml of an aqueous solution in which 0.05 g of silicotungstic acid (H ₄ SiW ₁₂ O ₄₀ ) was dissolved was placed in a 50 ml flask, 1 g of activated carbon was added, and the mixture was stirred at 20 to 30 ° C., and then water was distilled off under reduced pressure. Then, DMB-2 was obtained according to Example 1 except that the obtained solid was calcined under reduced pressure at 100 ° C. for 4 hours. Isomerization rate is 91.8%, DMB-1,
The two-fold yield was 97.6%.

Example 6 0.94 g of a catalyst prepared by supporting on activated carbon and calcining in accordance with Example 5.
Is filled in a glass tube with an inner diameter of 7 mm, and DMB-1 is placed therein at 20
DMB-2 was obtained by circulating the solution at a liquid superficial velocity of 6.5 h ^-1 . The activity of the catalyst was maintained even after distribution of 1980 ml (1386 g) of DMB-1. Isomerization rate is 91.2%, DMB-1,2 recovery rate is 98.9
%Met.

Example 7 DMB-2 was obtained according to Example 1 except that DMB-1 was passed at 30 ° C. at a liquid superficial tower velocity of 5.6 h ⁻¹ . Isomerization rate is 93.1%,
The DMB-1,2 recovery rate was 99.3%.

Claims (6)

[Claims] 1. A heteropoly acid is used as a catalyst for isomerizing 2,3-dimethyl-1-butene to produce 2,3-dimethyl-2-butene. 2,3-Dimethyl-2.
-Butene manufacturing method. 2. The method for producing 2,3-dimethyl-2-butene according to claim 1, wherein the heteropolyacids are supported on activated carbon for use. 3. The 2,3-dimethyl-2 according to claim 1, wherein the heteropolyacids are Keggin-type heteropolyacids.
-Butene manufacturing method. 4. The Keggin-type heteropolyacid is H ₄ SiW ₁₂ O.
_The method for producing 2,3-dimethyl-2-butene according to claim 3, which has a composition of ₄₀ . 5. The method for producing 2,3-dimethyl-2-butene according to claim 1, wherein the heteropolyacid is phosphotungsten molybdic acid. 6. The method for producing 2,3-dimethyl-2-butene according to claim 1, which is carried out by a flow system.