JPS622849B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a ruthenium catalyst for hydrogenation reaction supported on a carrier. Many ruthenium catalysts supported on carriers are known, such as Platinum Metal Rev 6 , 12
(1962) describes a method for reducing hydrogen by impregnating an aqueous solution of ruthenium chloride into a carrier,
No. 30696 discloses a method in which potassium ruthenate is supported on a carrier and activated by heat treatment at a temperature of 150 to 500°C in the presence of carbon dioxide gas. However, these conventional ruthenium catalysts are effective only in certain specific reactions, limiting the fields of use, and have drawbacks such as insufficient low-temperature activity and durability. From this perspective, the present inventor conducted extensive research on ruthenium catalysts that have low-temperature activity and durability, and are useful for the hydrogenation of various general-purpose organic compounds. Completely adsorbed on the carrier as ruthenium,
The present invention was completed by discovering that it is important to completely reduce this ruthenium hydroxide to a metallic state, to make the particle size of ruthenium metal as small as possible, and to uniformly disperse it in a carrier. That is, the present invention provides hydrocarbon-based aromatic nuclei, aromatic nuclei having substituents such as amino groups, phenolic hydroxyl groups, and carboxylic acids under mild conditions;
Furthermore, the present invention provides a ruthenium catalyst that can hydrogenate petroleum-based liquid unsaturated resins that are difficult to hydrogenate with common catalysts. In one embodiment of the production method for obtaining the ruthenium catalyst of the present invention, a carrier such as alumina is added and suspended in an aqueous solution of an alkali metal hydroxide such as sodium hydroxide, and the ruthenium catalyst is heated at 40 to 60°C.
The temperature was raised to , and an aqueous ruthenium chloride solution was poured into the mixture. After about 10 minutes, the liquid becomes transparent and the ruthenium chloride is completely adsorbed on the alumina as ruthenium hydroxide, giving it a black color. Next, an aqueous solution of sodium borohydride (hereinafter abbreviated as SBH) was added to the suspension at a temperature of 40°C to 40°C.
Keep it at 80℃ and drop it in about 1 hour. At this time, hydrogen gas is violently generated and ruthenium hydroxide is reduced to ruthenium metal. After completion of reduction, the mixture is cooled to room temperature, washed with water, and left as is or dried to obtain a ruthenium catalyst. The carrier used for the ruthenium catalyst of the present invention includes activated carbon, alumina, silica, silica alumina, diatomaceous earth, zeolite, etc., but is not particularly limited. The alkali used in producing the product of the present invention is a strong base such as sodium hydroxide, potassium hydroxide, lithium hydroxide, etc., and the amount used is 10 to 40% based on the carrier.
Weight percent is preferred. If the amount is less than 10% by weight, the adsorption of ruthenium onto the carrier is incomplete, and when the catalyst is washed with water, it becomes a colloid and ruthenium comes off the carrier, causing loss and deteriorating the performance of the catalyst. 40 again
There is no problem in using more than % by weight, but it is uneconomical and at the same time only unnecessarily increases the number of washings. When using sodium bicarbonate, sodium carbonate, etc., which have weak basicity, complete adsorption of ruthenium onto the carrier cannot be expected. The ruthenium salt used in producing the product of the present invention may be any salt as long as it can be adsorbed to the carrier as ruthenium hydroxide in an aqueous alkali metal hydroxide solution, but it must be completely adsorbed to the carrier. Ruthenium chloride is particularly suitable. When producing the product of the present invention, the temperature at which the ruthenium salt is adsorbed onto the carrier is preferably in the range of 40 to 60°C.
At low temperatures, the adsorption of ruthenium is slow, which may cause variations in catalyst activity, and at high temperatures, adsorption is too rapid and some of the ruthenium may not be adsorbed onto the carrier and may settle, making it difficult to obtain a catalyst of consistent quality. The amount of SBH used in producing the product of the present invention is preferably in the range of 1 to 2 times the weight of ruthenium metal. If the amount used is small, there is a possibility that unreduced ruthenium hydroxide remains, and if the amount used is too large, it is uneconomical and increases the number of washings. When manufacturing the product of the present invention, ruthenium hydroxide is
The temperature for reduction with SBH is preferably 40 to 70°C. At low temperatures, the reduction rate is extremely slow, and at high temperatures, the reduction rate is too fast, which may cause variations in catalyst activity. The amount of ruthenium supported in the product of the present invention is
It is preferably 0.01 to 5% by weight, but is not particularly limited. The thus obtained catalyst of the present invention usually contains 0.1 to 0.02% by weight of boron, which is considered to be one of the factors that improves the catalyst performance. The product of the present invention has unprecedented low-temperature activity and durability in hydrogenation reactions. For example, γ−
Using the catalyst of the present invention in which 2% of ruthenium is supported on alumina, p-tert-butylphenol is heated to 80% hydrogen pressure.
When hydrogenation is carried out under Kg/cm ² , hydrogen absorption begins at 60°C and the reaction is completed in 20 minutes at 80°C. It is surprising that no decrease in activity was observed even after this catalyst was recovered and used up to six times, and its low-temperature activity was excellent. By the way, when the same substance is hydrogenated under the same conditions using a 5% supported ruthenium-alumina catalyst using a general conventional method, the minimum
It requires a temperature of 150℃ and is not practical due to its poor durability. Further, the present invention will be explained in detail with reference to Examples. Example 1 980g of γ-alumina with a particle size of 60μ is placed in 55g of water, and 1.5g of a 20% sodium hydroxide aqueous solution is added to the water.
was added and stirred at room temperature for 30 minutes. Set the liquid temperature to 40℃,
Ruthenium chloride aqueous solution 3 containing 20g of ruthenium metal was added in three parts, and the liquid temperature was raised to 50°C.
The mixture was kept at ±5°C and stirred for 1 hour to adsorb ruthenium onto the carrier. Next, raise the temperature of the liquid to 60±5
Aqueous solution 1 containing 40g of SBH in a lever kept at ℃
was added continuously for one hour to perform the reduction. After this, wait for the liquid to cool down to room temperature.
After washing continuously with water using a centrifuge until the pH of the washing solution reached 9, drying with hot air at 110℃ for 10 hours was performed.
1003 g of 2% supported ruthenium-gamma-alumina catalyst was obtained. Analysis of this catalyst revealed that ruthenium was found.
It contained 1.89% by weight and 0.12% by weight of boron. 1 g of this catalyst was mixed with 15 p-tert-butylphenol.
When the reaction was carried out while raising the temperature at an initial hydrogen pressure of 80 kg/cm ² , hydrogen absorption started at 60°C and reached 80°C after 22 minutes, and hydrogen absorption stopped and nuclear reduction occurred. The reaction has finished. After removing the reaction product from the autoclave and separating the catalyst, the solvent is distilled off.
15.3 g of -tert-cyclohexanol was obtained. This product contained 55% cis isomer and 45% trans isomer. Example 2 A ruthenium carbon catalyst was obtained in the same manner as in Example 1, using activated carbon instead of γ-alumina as a carrier in the preparation of the catalyst in Example 1. 0.4g of this catalyst was charged into an autoclave along with 50g of liquid polybutadiene with an average molecular weight of 3000.
Hydrogenation was carried out at an initial hydrogen pressure of 50 Kg/cm ² and a reaction temperature of 125±8°C. After 300 minutes, 20.4 of hydrogen was consumed and the reaction was completed. The obtained hydrogenated compound had an iodine number of 2.3. Examples 3 to 7 When a hydrogenation reaction was carried out using the catalyst of Example 1 in an amount of 5% based on the raw material, the reaction time and the yield of the nuclear reduction product were as shown in Table 1.

[Table] Examples 8 to 10 Catalysts obtained by replacing γ-alumina as a carrier with activated carbon and diatomaceous earth in the catalyst preparation of Example 1, and replacing sodium hydroxide with potassium hydroxide in the catalyst preparation of Example 1 When coumarin was hydrogenated using a catalyst, the results shown in Table 2 were obtained.

[Table] Comparative Example 1 98 g of γ-alumina with a particle size of 60μ was placed in 500 ml of water, and while stirring, a ruthenium chloride aqueous solution containing 2 g of ruthenium metal was added, and 1
Sufficient adsorption was achieved by stirring for hours. Next, check the liquid temperature
While maintaining the temperature at 60±5° C., 100 ml of an aqueous solution containing 4 g of SBH was gradually introduced into the solution to perform reduction. After that, it was washed with water and dried, and 2% supported ruthenium-γ-
100g of alumina catalyst was obtained. Using 1 g of this catalyst, a reduction reaction of p-tert-butylphenol was carried out under the same reduction conditions as in Example 1. Hydrogen absorption started at 100°C and took 55 minutes to stop. After filtering the catalyst, the solvent was distilled off to give p-tert-butylcyclohexanol.
15.1g was obtained.

Claims (1)

[Claims] 1. A carrier is suspended in an aqueous alkali metal hydroxide solution, a ruthenium salt solution is added to this suspension, adsorbed onto the carrier, and then reduced with sodium borohydride. A method for producing a ruthenium catalyst for hydrogenation reaction. 2. The method according to claim 1, wherein the alkali metal is one or more selected from sodium, potassium, and lithium. 3. The method according to claim 1, wherein the ruthenium salt is ruthenium chloride. 4. The method according to claim 1, wherein the temperature at which ruthenium is adsorbed onto the carrier is 40 to 60°C. 5 The temperature for reduction with sodium borohydride is 40
The method according to claim 1, wherein the temperature is between 80°C and 80°C. 6 The boron content contained in the catalyst is 0.01~
A method according to claim 1, wherein the amount is 0.2% by weight.