JPH02279643A - Method for producing isopropyl alcohol - Google Patents

Abstract

PURPOSE:To readily and stably for long time obtain the subject compound in high reactivity and selectivity by reducing acetone with hydrogen using carried ruthenium catalyst and reacting so as concentration of isopropyl alcohol of reaction element to be specific value. CONSTITUTION:Acetone is supplied H2 in an amount of 1 to 50 times of theoretically required hydrogen to a reducing reaction by hydrogen preferably using isopropyl alcohol(IPA) as a solvent, where the concentration of IPA in the reaction system is made as >=50wt.%, then reacted at 0 to 200 deg.C under normal pressure or increased pressure in the presence of ruthenium catalyst such as ruthenium chloride carrying 0.01 to 5wt.% carrier such as heat-resistance gamma-alumina, silica or activated charcoal of coconut shell to afford the objective compound useful as solvent or raw materials of various organic drugs, etc.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for producing isopropyl alcohol (sometimes abbreviated as IPA).Specifically, acetone is reduced with hydrogen to produce solvents, raw materials for various organic chemicals, etc. The present invention relates to a method for producing isopropyl alcohol useful as an alcohol.

(Prior Art) Conventionally, IPA has been produced by a hydration reaction of propylene. This hydration reaction involves (1) a direct hydration method in which a tungsten-based catalyst is reacted with a large excess of water under conditions of 240-270°C and 150-200 atm;
There is an indirect hydration method in which sulfuric acid is carried out at 21 to 28 atmospheres using 100% sulfuric acid, and then IPA is obtained by hydrolysis, but the conditions are very harsh for industrial production, and the indirect method has the problem of corrosion of the equipment. There is also. Also, since excess water is used in the reaction, I
Since PA and water form an azeotropic mixture, there is a drawback that equipment such as separation process becomes complicated.

Therefore, a method of reducing acetone with hydrogen has also been proposed as a method of producing IPA without using water in the reaction.

It is known that the carbonyl group of acetone can be reduced with a metal catalyst, for example, in Japanese Patent Publication No. 46-9136 and Organic Synthesis, Vol. 27, No. 1, p. 69 (1969).
(2010) describes a method for producing palladium catalysts that can be used for reducing carbonyl groups by attaching palladium salts and molybdenum compounds to a carrier and then reducing the mixture with hydrogen by force-calcining or without force-calcining. .

In addition, JP-A-62-12729 describes an improved method for hydrogen reduction of acetone using a Raney nickel catalyst to obtain IPA, in which the amount of alkali present in the catalyst is determined by the pFI value of the aqueous solution in which the catalyst is immersed. Using a catalyst in the range of 7.0 to 8.2, the water content of the reaction system is 5% by weight or less, the reaction temperature is in the range of 100 to 160°C, and the unreacted amount of acetone is 0.5% by weight. % or more.

[Problem to be solved by the invention]

However, the hydrogen reduction methods described in the above-mentioned publications and literature use a suspended bed reaction mode, and therefore have the problem that the equipment required to separate the produced alcohol from the catalyst is complicated. In addition, in the method using a palladium catalyst, although it is recognized that the activity is improved by the addition of molybdenum, there is no mention of the yield of rPA.
However, in the method using a Raney nickel catalyst, the reaction is carried out in such a way that the amount of unreacted acetone is 0.5% by weight or more, so the yield of IPA does not exceed 99.5%, and the amount of unreacted acetone is Although excessive equipment is required to separate acetone and the product IPA, such a method is not advantageous for industrial mass production even though IPA can be produced by reducing acetone with hydrogen. The problem is that it is not.

[Means to solve the problem]

The present invention uses a supported ruthenium catalyst as a catalyst in a method for producing isopropyl alcohol by hydrogen reduction of acetone, and the concentration of isopropyl alcohol in the reaction system is reduced to 50! characterized in that the reaction is carried out at an amount of i% or more;
The present invention provides a method for producing isopropyl alcohol in which IPA can be stably obtained from acetone for a long period of time at a high reaction rate and with high selectivity despite reaction conditions that are much milder than those of conventional methods.

In the supported ruthenium catalyst used in the method of the present invention, ruthenium is supported on a suitable carrier, and the supporting ratio is usually 0.01 to 5% by weight, preferably 0.02 to 3% by weight. In addition, the carrier is a heat-resistant inorganic compound carrier,
Examples include synthetic gel carriers such as alumina and silica, and natural inorganic carriers such as diatomaceous earth, porous clay, and carbon.

The method of the present invention can be carried out in any manner such as batchwise or continuous, but a fixed bed is preferred since a suspended bed catalyst requires a catalyst separation step. Further, in a fixed bed, downward flow is preferable because upward flow may cause the supported ruthenium catalyst to fluidize and cause a decrease in activity.

The product IP is used as a solvent to dilute the raw material acetone.
Preferably A is used. In addition, it is possible to dissolve acetone and the product IPA and use it as a solvent if it has no reactivity with acetone, but it is not preferable to use water as a solvent or mix it with water because it will be very difficult to separate it from the product IPA. Moreover, if it is other than IPA, it is not preferable because it requires a large amount of equipment for separation from product IPA.

In the hydrogen reduction reaction of acetone in the presence of a supported Ru catalyst in the method of the present invention, it is necessary to carry out the reaction with the IPAtffi degree in the reactor set to 50% by weight or more. concentration is 5
If it is less than 0% by weight, the reaction heat will be large and the reaction temperature will not be stable, and high activity and selectivity will not be obtained.
Such problems arise.

The amount of hydrogen supplied to the hydrogen reduction reaction system is 1 to 50 times, preferably 1 to 30 times, the amount of hydrogen theoretically required for the hydrogen reduction reaction.
times, most preferably about 1 to 2.0 times. If too much hydrogen is supplied, it will be a waste and the associated equipment such as hydrogen recovery system and circulation system will be enormous and wasteful.

The hydrogen reduction reaction is usually carried out at a temperature of 0 to 200°C, preferably 10 to 200°C.
It is carried out at 170°C, most preferably in the range of 20-150°C. If the reaction temperature is too high, a high conversion rate cannot be obtained due to chemical equilibrium, and side reactions may also occur, which is undesirable. Also,
If the reaction temperature is too low, problems such as a slow reaction rate will occur.

The total pressure of the hydrogen reduction reaction is usually normal pressure to elevated pressure, preferably normal pressure to 5 Q kg/culQ, and ji is also preferably normal pressure to 30 kg/calG. Since the hydrogen reduction reaction of acetone easily proceeds at the above pressure, increasing the reaction pressure more than necessary will only increase the construction cost of the apparatus and is wasteful.

〔Example〕

The present invention will be explained in more detail with reference to experimental examples below. The percentages given in these examples are by weight unless otherwise stated.

Catalyst production example-1 γ-alumina molded into a cylindrical shape of 3Bφ x 3 fins with a concentration of 0
．． The skin was impregnated with an acidic solution of 8% ruthenium chloride (l hydrate) in hydrochloric acid and dried at 110° C. for one day.

Next, the dried product was heated at a temperature of 400°C under a hydrogen stream for 1 hour.
After 6 hours of reduction treatment, the composition was Ru (0.5%)/γ-^
120. A supported ruthenium catalyst was obtained.

Catalyst Production Example-2 The same operation as Catalyst Production Example-1 was carried out except that coconut shell activated carbon crushed into 4 to 8 meshes was used as the carrier. I got a catalyst.

Example-1 Ru (0.5%)/γ prepared according to Catalyst Production Example-1
- In a stainless steel autoclave with an internal volume of 200111 and equipped with a cage-type stirrer, a hydrogen supply pipe, and a product liquid extraction pipe filled with 5 g of alumina catalyst, acetone 10%, IPA9
1251Ili of raw materials having a composition of 0% were charged, and the reaction was carried out for 3 hours at a reaction temperature of 60° C., a reaction pressure of 90 kg/cd-G, and a stirring speed of 750 rpm. After cooling the autoclave, the produced liquid was extracted and analyzed using a gas chromatograph. The results are shown in Table-1.

Example-2 The same operation as in Example-1 was performed except that the Ru (0.5%)/activated carbon catalyst prepared according to Catalyst Production Example-2 was used and the reaction time was 1 hour. The results shown are obtained.

Example 3 The same operation as in Example 1 was performed except that raw materials having a composition of 40% acetone and 60% IPA were used and the reaction time was 12 hours, and the results shown in Table 1 were obtained.

Comparative Example-1 The same operation as in Example-1 was performed except that raw materials containing 100% acetone and IPAO% were used and the reaction time was 24 hours. Hydrogen absorption stopped after 8 hours, but since only about 16% of the theoretical value was absorbed, the reaction continued until 24 hours, but no new hydrogen absorption was observed after that, Table 1
The results shown are obtained.

Example-4 Ru (0.5%)/ prepared according to Catalyst Production Example-2
Activated carbon catalyst 5001Ill was equipped with an inner diameter of 30mm equipped with a thermometer protection tube of outer diameter of 10m. It was filled into a stainless steel reaction tube.

The inlet temperature of the catalyst layer was set at 50°C, and 10% acetone was added to this.
, IPA 90% solution at 217 hours, hydrogen at 931/
It was continuously supplied from the top of the reaction tube at a reaction pressure of 9 kg/cffl-G. Table 1 shows the results at the 8th hour and 100th hour of supply.

Comparative Example-2 The same operation as in Example-4 was carried out except that a liquid with a composition of 60% acetone and 40% IPA was used and hydrogen was changed to 401/hour, but the heat generation was large and stable operation was not possible. It was possible. Also, the acetone conversion rate 8 hours after supply was 94.
%, and a large amount of by-products of diisopropyl ether and diacetone alcohol were observed.

Table 1 [Effects of the Invention] According to the production method of the present invention, acetone can be stably reduced with hydrogen at a high conversion rate, and isopropyl alcohol can be produced with a high selectivity.

Claims (1)

[Claims] In a method for producing isopropyl alcohol by hydrogen reduction of acetone, a supported ruthenium catalyst is used as a catalyst, and the isopropyl alcohol concentration in the reaction system is reduced to 50% by weight.
A method for producing isopropyl alcohol, which is characterized by carrying out the reaction as described above.