JPS6368538A - Production of methyl isobutyl ketone - Google Patents

Abstract

PURPOSE:To produce methyl isobutyl ketone useful as an organic solvent by one stage, by using a catalyst comprising palladium and niobium pentoxide heat-treated in a specific temperature range as essential components of catalyst and reacting acetone with hydrogen. CONSTITUTION:Acetone is reacted with hydrogen by the use of a novel highly active catalyst consisting of palladium and niobium pentoxide which is heat- treated at 400-550 deg.C and dehydrated to give methyl isobutyl ketone. In the catalyst, palladium may be supported on the niobium pentoxide and the amount of palladium used is 0.001-10%, preferably about 0.01-5% based on niobium pentoxide by weight ratio. EFFECT:The reaction can be advantageously advanced by using the catalyst having high activity, high selectively, high stability and high power.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an improved method for producing methyl isobutyl ketone (hereinafter abbreviated as MIBK), which is highly useful as an organic solvent.

[Prior art] MIBK has conventionally been produced by a so-called three-step process using acetone and hydrogen as raw materials via diacetone alcohol and mesityl oxide. Since the production process involves an equilibrium reaction, it is not possible to increase the raw material conversion rate, making it an extremely inefficient method. Therefore, various methods for directly producing MIBK from acetone and hydrogen in one step have been proposed, and for example, palladium-ion exchange resin, palladium-zirconium phosphate, palladium-alumina, etc. have been used as catalysts. All of them had many problems in terms of catalyst activity, catalyst life, etc.

[Problems to be Solved by the Invention] The present invention aims to solve the above-mentioned problems of the prior art and provide a method for producing methyl isobutyl ketone using a catalyst that has excellent catalytic activity and can be used in an industrially stable state. It is something to do.

[Means for Solving the Problems] In order to solve the problems, the present inventors have endeavored to develop a new highly active catalyst that can directly produce MIBK from acetone and hydrogen in one step. The present invention was achieved based on the knowledge that efficient MIBK can be obtained by using a catalyst containing niobium pentoxide as an essential component that has been heat-treated at 550° C. or lower.

That is, the structure of the present invention is that when producing MIBK in one step by reacting acetone and hydrogen, palladium and 40
This is a method for producing MIBK using a catalyst containing niobium pentoxide as an essential component that has been heat-treated between 0°C and 550°C.

The method of the present invention will be explained in detail below. First, let's talk about niobium pentoxide. Hydrous niobium oxide has traditionally been called "niobic acid," and in recent years it has attracted strong academic interest as a solid acid catalyst active in olefin hydration reactions. It has become. As a result of the inventors' studies,
"Niobic acid" has been found to be extremely effective as a catalyst for producing α,β-unsaturated ketones by combining ketones, and has already been proposed. However, “niobic acid”
still has the following problems. In other words, since it is an amorphous solid, sufficient results cannot be obtained with respect to the molding required when solid catalysts are used in practical processes, and their strength is weak.
Even if it can be used in laboratory reactions, there are still problems in practical application. The inventors of the present invention have continued to study this point and found that there are other
It was discovered that niobium pentoxide, which had been heat-treated and dehydrated, had a high acetone condensation activity, and it was found that if this substance was used together with palladium, MIBK could be efficiently produced in one step from acetone and hydrogen.

Niobic acid was reported by Iizuka et al. [3rd Acid Processing Study Group, Proceedings of Solid Acid Catalysts and Organic Synthesis, P1-4,
Catalysis Society of Japan (1983) (+N is surface Vo1.23
No., B P 471-481 (1985)], those calcined at low temperatures of 100 to 300°C show strong acid strength and high catalytic activity, while those heat-treated at 400°C or higher show solid acid strength. The findings discovered by the present inventors are extremely surprising considering that it has been said that the catalytic activity is low due to a decrease in

Niobium pentoxide heat-treated at 400° C. or higher does not contain water and has a high solid strength, so it is suitable as a practical catalyst. However, if the heat treatment temperature is 550° C. or higher, the phase transition of niobium pentoxide will proceed and the catalytic activity will be significantly reduced, which is not preferable.

To produce niobium pentoxide, it is usually best to heat-treat niobic acid. The raw material ``niobic acid'' is commercially available, but it may also be one prepared by precipitation from a soluble niobium compound, such as a niobium chloride solution.

When producing MIBK from acetone, the catalyst requires a hydrogenation function. Although niobium pentoxide itself does not have a very high hydrogenation function, it becomes an effective catalyst when used in combination with a platinum metal element such as palladium or rhodium, and palladium is used in the present invention. Palladium may be supported on niobium pentoxide, or may be physically mixed with niobium pentoxide in a state such as palladium-carbon or palladium-alumina. The heat treatment of niobium pentoxide can be carried out either before or after the support-mixing with palladium. The amount of palladium used is 0.001 to 10% by weight relative to niobium pentoxide, preferably o,
oi to about 5% is preferable. Palladium may be supported on niobium pentoxide by a known method, such as by impregnating it with a soluble palladium compound and then reducing it with hydrogen, hydrazine, or the like.

The reaction can be carried out in either gas phase or liquid phase, but is preferably carried out in liquid phase. In the case of liquid phase, the reaction temperature is preferably below the critical temperature of acetone (235°C). Since catalytic activity is not expressed at too low a temperature, the temperature is preferably between 100°C and 2°C.
The temperature should be between 00°C. The reaction pressure is higher than the natural generation pressure of acetone and lower than 150 kg/cm2, more preferably 8 ki;
The pressure is set between /Cm2 and 50kg/cm2 using hydrogen. The catalyst may be used in either suspended bed or fixed bed form. It is preferable to suppress the conversion rate of acetone to 50% or less.

[Examples] The present invention will be briefly and concretely explained using Examples below, but the present invention is not limited to these Examples unless the gist thereof is exceeded.

In the example, niobium pentoxide obtained by baking acid powder at 400°C,
A catalyst was prepared by impregnating a palladium chloride aqueous solution to a Pd concentration of 0.3% and reducing it at 200° C. in a hydrogen stream.

2.2 g of this catalyst and 40 ml of acetone were placed in an autoclave, heated to 140°C, and pressurized to 20 kg/cm' with hydrogen to carry out a reaction. Hydrogen consumed as the reaction progressed was continuously supplied, and the total pressure was always kept constant.

After the reaction solution was cooled, the catalyst was separated and analyzed. The results are shown below in Part 1.
Shown in the table.

Example 2 Calcination temperature of niobic acid was 500°C, reaction pressure was 10kg/
The reaction was carried out in the same manner as in Example 1, except that the volume was changed to cm2.

Example 3 Niobium pentoxide 3.5 obtained by calcining niobic acid at 500°C
g and 1% palladium-carbon (Japan Engelhard Co., Ltd. Iu
)1. Oa was charged and reacted under the same conditions as in Example 2.

All results are also shown in Table 1.

Table 1 tPA: Isopropyl Alcohol DISK Nidiisobutyl Ketone [Effects of the Invention] As described above, according to the method of the present invention, M
When producing IBK, the reaction can be carried out advantageously by using a highly active, highly selective, highly stable, and highly strong catalyst containing palladium and a specific niobium pentoxide as essential components.

Claims (1)

[Claims] When acetone and hydrogen are reacted in the presence of a catalyst to produce methyl isobutyl ketone in one step, a catalyst containing palladium and niobium pentoxide heat-treated at a temperature of 400°C to 550°C as essential components is used. A method for producing methyl isobutyl ketone, characterized by: