JP2737297B2 - Method for producing methyl isobutyl ketone - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing methyl isobutyl ketone by a single-step reaction using acetone and hydrogen as raw materials.

Methyl isobutyl ketone (hereinafter sometimes referred to as “MIBK”) is useful as a raw material for organic solvents, paints, stabilizers, and the like.

<Conventional technology> MIBK is usually manufactured industrially by the following three-step method using acetone and hydrogen as raw materials.

The feature of this three-stage method is that the condensation, dehydration, and hydrogenation steps shown in the above formula are sequentially performed. First, acetone was converted to 10% using a solid base catalyst such as barium hydroxide.
Diacetone alcohol is synthesized by reacting at ~ 20 ° C and normal pressure liquid phase, and then the diacetone alcohol obtained by condensation is converted to liquid phase in the presence of acid catalyst such as sulfuric acid and phosphoric acid. Dehydration reaction is performed by heating to 100 to 120 ° C to obtain mesityl oxide. Then, after separating and purifying the mesityl oxide, hydrogenation is carried out in the presence of a Raney nickel catalyst or the like to produce MIBK.

This method is widely practiced industrially, but condensation,
There are three reaction steps, dehydration and hydrogenation. In each of these steps, it is necessary to separate and purify intermediates such as diacetone alcohol and mesityl oxide, and the operation is complicated. Furthermore, since the condensation reaction of acetone to diacetone alcohol is an equilibrium reaction, the conversion rate is as low as about 15%.

For this purpose, studies are being conducted to produce MIBK from acetone and hydrogen in a single step. This method has an equilibrium advantage, can increase the feed conversion per pass, and is economically advantageous as compared with the three-stage method.

Several processes have been proposed as a method for producing MIBK by such a one-step method (for example, Bulletein o
f The Japan Petroleum Institute 16 (1) P55-59, Hy
drocarbon, Processing 1985 Dec.P51 ~ 52, Hydrocarbon
Processing 1977 Nov. P184, Chemical Engineering 1968
May P108), however, only discloses a general method using a combination of distillation columns for the purification step after the reaction.

<Problems to be Solved by the Invention> An object of the present invention is to obtain high-purity MIBK in a high yield in a method for producing MIBK from acetone and hydrogen as raw materials.

<Means for Solving the Problems> As a result of intensive studies to achieve the above object, the present inventors have found that in a reaction for producing MIBK from acetone and hydrogen, mesityl oxide (CH ₃ COCHC (CH ₃ ) ₂ ) Is inevitably produced as a by-product, which leads to waste of raw materials and a reduction in the reaction yield. In addition, the boiling point of the mesityl oxide is 129 ° C.
In addition, the boiling point of MIBK is close to 117 ° C, so it is difficult to sufficiently separate it from MIBK using only the conventional purification by distillation, which lowers the purity of the product MIBK. I found that Therefore, as a result of further study on a method of removing the mesityl oxide, prior to distillation of the MIBK, the reaction yield was reduced by reacting the mesityl oxide contained in the MIBK with hydrogen and converting it to MIBK. The product MIBK without coming
The present inventors have found that the purity of the compound can be maintained high, and have reached the present invention.

That is, the present invention relates to a method for producing methyl isobutyl ketone from acetone and hydrogen, comprising: (a) supplying acetone and hydrogen to a reactor having a catalyst, and reacting the acetone with hydrogen to produce methyl isobutyl ketone; (B) The reaction liquid obtained in the above step (a) is supplied to the first distillation column, and the liquid mainly containing unreacted acetone obtained from the top of the column is recycled to the reactor in the above step (a). And
(C) contacting the liquid containing methyl isobutyl ketone as a main component obtained in step (b) with hydrogen in the presence of a hydrogenation catalyst; Converting mesityl oxide contained in the liquid containing methyl isobutyl ketone as a main component into methyl isobutyl ketone; and (d) supplying the liquid obtained in the above step (c) to the second distillation column. And distilling off the low boiling by-products from the top of the column to obtain a liquid containing methyl isobutyl ketone as a main component at the bottom of the column. (E) Using methyl isobutyl ketone obtained in the above step (d) as a main component. Supplying a liquid to be distilled to a third distillation column to obtain high-purity methyl isobutyl ketone from the top of the third distillation column.

Hereinafter, the method of the present invention will be described with reference to the flow sheet of FIG.

A mixture of fresh acetone supplied from line 1, acetone recycled from first distillation column 9 through line 3, and hydrogen gas supplied from line 2 are led to reactor 4. The reactor 4 is filled with a catalyst, and MIBK is reacted with acetone and hydrogen in the presence of the catalyst.
Is generated. Also, as by-products, isopropanol,
Mesityl oxide, diisobutyl ketone, methyl isobutyl carbinol, water, etc. are produced. Examples of the catalyst for the reactor 4 include an acid-type ion exchange resin, palladium-carbon (for example, see German Patent No. 1238453), and a catalyst in which palladium is supported on zirconium phosphate (for example, see Japanese Patent Publication No. 49-6994). ), A catalyst in which palladium is supported on an H-type zeolite (for example, see Japanese Patent Publication No. Sho 46-2463), a catalyst comprising niobic acid and palladium (for example,
JP-A-61-78745) is used.

Reaction conditions vary depending on the catalyst used, but usually,
The reaction temperature is 100-200 ° C and the reaction pressure is 5-50 atm.

The reaction liquid from the reactor 4 is led to the gas-liquid separator 6 through the line 5, where the unreacted hydrogen gas is purged from the line 7.

The reaction liquid from which unreacted hydrogen gas has been removed is led to the first distillation column 9 through the line 8.

In the first distillation column 9, unreacted acetone is distilled off at the top, and a liquid containing MIBK as a main component is extracted from the bottom.
Unreacted acetone withdrawn from the top is recycled to the reactor 4 again through the line 3. The operating conditions of the first distillation column 9 are not particularly limited, but usually the column bottom temperature is 80 to 110 ° C and the top pressure is 700 to 800 mmHg.

On the other hand, the liquid containing MIBK as a main component extracted from the bottom of the first distillation column 9 is led to a liquid-liquid separator 11 through a line 10, where water produced by the reaction and an oil layer containing MIBK are removed. And water is purged through the line 12 to the outside of the system. The liquid composed of an oil layer containing MIBK after water has been separated is led to a hydrogenation reactor 14 through a line 13. In the hydrogenation reactor 14, in the presence of the hydrogenation catalyst, hydrogen supplied from the line 15 reacts with mesityl oxide contained in the liquid derived from the line 13 to convert mesityl oxide to MIBK. . The content of mesityl oxide contained in the liquid led from the line 13 varies depending on the catalyst used in the reactor 4 and the reaction conditions, but is about 0.5 to 5% by weight. As a hydrogenation catalyst for the hydrogenation reactor 14, a palladium-based catalyst, a nickel-based catalyst, or the like is used, but a palladium-based catalyst is preferably used. The hydrogenation reaction conditions are usually a reaction temperature of 50 to 150 ° C. and a reaction pressure of 2 to 20 atm. By conducting the reaction under such conditions, mesityl oxide is almost completely converted to MIBK.

Conversion of mesityl oxide to MIBK in the hydrogenation reactor 14 improves the yield of MIBK and eliminates mesityl oxide contained in the purified MIBK obtained through the line 22, thereby improving the purity of MIBK. There is an advantage of doing so.

The liquid discharged from the hydrogenation reactor 14 is led to a second distillation column 17 through a line 16. The operating conditions of the second distillation column are not particularly limited, but usually the column bottom temperature is 110 to 130 ° C. and the column top pressure is 700 to 800 mmHg. From the top of the second distillation column 17,
Light boiling by-products such as isopropanol by-produced in the reactor 4 are distilled off through a line 18. The liquid at the bottom is the line
The high purity MIBK is extracted from the top of the third distillation column 20 through the line 22 through the top of the third distillation column 20 through 19.

On the other hand, by-products such as methyl isobutyl carbinol and diisobutyl ketone are discharged from the bottom of the third distillation column 20 through a line 21. The operating conditions of the third distillation column are not particularly limited, but usually, the bottom temperature is 150 to 180 ° C and the top pressure is 700 to 800 mmHg.

As described above, after unreacted acetone is recovered in the first distillation column 9, mesityl oxide as a by-product is converted to MIBK in the hydrogenation reactor 14, and then the second and third distillations are performed. By doing so, MIBK of high purity can be obtained with good yield.

<Examples> Hereinafter, the present invention will be described with reference to examples, but the scope of the present invention is not limited by these examples.

Example 1 Niobic acid (cylindrical form, manufactured by CBMM) was immersed in an aqueous solution of palladium chloride, reduced with hydrazine, calcined at 300 ° C., and 40 ml of a catalyst (palladium carrying amount 0.1% by weight) was obtained.
m into a vertically arranged reaction tube, temperature 150 ℃, pressure
Under a condition of 20 kg / cm ² , acetone was introduced into the reactor at a supply rate of 158 g / hr (LHSV = 5) and hydrogen at 256 Nml / min, and the reaction was carried out to obtain a reaction solution having the composition shown in Table 1.

The reaction solution was analyzed by gas chromatography and Karl Fischer.

After distilling the reaction solution obtained in the above reaction and distilling off unreacted acetone, the distillation residue is separated into an oil layer and an aqueous layer.
An oil layer liquid having the following composition was obtained.

 The distillation conditions are as follows.

Distillation column theoretical plate number: 10 stages Reflux ratio: 1.0 Head pressure: 620 mmHg The liquid and hydrogen of the above oil layer were converted to a palladium catalyst supported on alumina (manufactured by Nippon Engelhard,
0.3%) into a vertically arranged reaction tube with an inner diameter of 28 mm.
Temperature 0.99 ° C., under a pressure of ^{10kg / cm 2, 64g / h} (LHSV =
4) Hydrogen was introduced at a supply rate of 40 Nml / min to carry out a hydrogenation reaction.

The composition of the reaction solution obtained by this reaction was as follows.

600 g of the liquid obtained by the above hydrogenation reaction was charged into a distillation column having 20 theoretical plates, and a reflux ratio of 2.5 and a top pressure of 300 mmHg
Distillation was performed under the following conditions. Separate each fraction that comes out,
Analysis by gas chromatography revealed that the fraction containing MIBK as a main component was weighed 502 g and its purity was 99.6% by weight.

Comparative Example 1 Using 600 g of the liquid before the hydrogenation reaction in Example 1, distillation was performed under the same conditions as those performed on the liquid after the hydrogenation reaction in Example 1.

Each of the distillate fractions was separated, analyzed by gas chromatography, and the fraction containing MIBK as a main component was collected. Its weight was 470 g and its purity was 98.5%.
And contained 1.1% of mesityl oxide.

<Effects of the Invention> As described above, according to the present invention, high-purity methyl isobutyl ketone can be obtained with a high yield.

[Brief description of the drawings]

 FIG. 1 is a diagram showing a preferred embodiment of the present invention. 1: Acetone flow, 2: Hydrogen flow, 3: Recycled acetone flow 4: Reactor, 6: Gas-liquid separator, 7: Purged hydrogen flow 9: First distillation column, 11: Liquid-liquid separator, 12: Purged water flow 14: hydrogenation reactor, 15: hydrogen stream, 17: second distillation column 18: light-boiling by-product stream, 20: third distillation column, 21: by-product stream 22: high-purity MIBK stream, 5, 8, 10 , 13,16,19: Pipe line

 ──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Katsuyuki Shioda 5-1 Sokai-cho, Niihama-shi, Ehime Prefecture Within Sumitomo Chemical Industries Co., Ltd. (56) References JP-A-61-85343 (JP, A) 52-15573 (JP, B1)

Claims (1)

(57) [Claims] 1. A method for producing methyl isobutyl ketone from acetone and hydrogen, comprising: (a) supplying acetone and hydrogen to a reactor having a catalyst, and reacting the acetone with hydrogen to produce methyl isobutyl ketone; b) The reaction liquid obtained in the above step (a) is supplied to the first distillation column, and the liquid mainly containing unreacted acetone obtained from the top of the column is recycled to the reactor in the above step (a). ,
(C) contacting the liquid containing methyl isobutyl ketone obtained in the above step (b) with hydrogen in the presence of a hydrogenation catalyst; Converting mesityl oxide contained in the liquid containing methyl isobutyl ketone into methyl isobutyl ketone, and (d) supplying the liquid obtained in the above step (c) to a second distillation column. Distilling off the low-boiling by-product from the top of the column to obtain a liquid containing methyl isobutyl ketone as a main component at the bottom of the column; (e) using methyl isobutyl ketone obtained in the above step (d) as a main component Supplying the liquid to a third distillation column to obtain high-purity methyl isobutyl ketone from the top of the column.