JPH0237213B2 - HIDOROHORUMIRUKASHOKUBAINOSHORIHO - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a treatment method for maintaining high activity of a rhodium-containing hydroformylation catalyst. Rhodium phosphine-based catalysts are known to have high activity to carry out hydroformylation reactions under mild reaction conditions. The characteristic of this mild reaction condition is that on the one hand it does not decompose substances that poison the hydroformylation catalyst, so if this catalyst is used for a long time, oxygen, halogen, sulfur, etc. contained in the raw gas liquid will be removed. The problem is that it is poisoned by trace components, oxidation by-products such as organic acids, aldehyde condensates, etc., resulting in a significant decrease in activity or substantial loss of activity. For example, in the hydroformylation of allyl alcohol, it was observed that a significant decrease in activity as shown in Reference Example 2 occurred. Therefore, the present inventors investigated various methods for restoring the activity, and found that rhodium, whose activity had decreased in the presence of a solid hydrogenation catalyst,
The present invention was completed based on the discovery that the activity of a tertiary phosphine-based hydroformylation catalyst (hereinafter referred to as a rhodium complex catalyst) can be recovered under mild conditions by hydrogen treatment of an organic solvent solution. As a method for activating and regenerating a rhodium complex catalyst, a method of heating under hydrogen pressure (see Japanese Patent Publication No. 48-43799) is known. In this example of the prior art, when converting the catalyst activity expressed as the butyraldehyde yield into a rate constant and determining the specific activity (R/R ₀ ) with respect to the initial value (R ₀ ), the catalyst decreased to 36%. was recovered to 53% by treatment at 60°C for 14 hours under a hydrogen pressure of 70 kg/cm ² , but this recovery rate cannot be said to be fully satisfactory. This also applies to Comparative Example 1 (specific activity after recovery: 40%). However, by using the method of the present invention in which hydrogen treatment is carried out in the presence of a hydrogenation catalyst, it is possible to recover the specific activity to nearly 100% even if the catalyst has a significantly decreased specific activity of 5% or less. Moreover, as seen in Example 1, the effect can be improved by treatment at extremely low pressure and in a short time. In addition, some proposals have already been made regarding the purification of raw materials and the maintenance and separation of catalyst liquid, but in the end, the deactivated catalyst liquid must be sent to a manufacturer or the like for rhodium recovery (see Catalyst Vol. 23, p. 174). Until now, a simple and effective activity recovery treatment method like the present invention has not been realized. The rhodium complex catalyst used in the present invention is
45-10730, Japanese Patent Publication No. 53-17573, etc., HRh (CO) (PR ₃ ) ₃ or Rh
(CO) ₂ (acetylacetate), Rh ₄ (CO) ₁₂ , Rh ₆
Rhodium carbonyl such as (CO) ₁₆ , CO, _H2 , etc.
HRh(CO) readily in the presence of tertiary phosphine
(PR ₃ ) Any substance that can be converted to ₃ can be used as a catalyst. Examples of the tertiary phosphine represented by PR ₃ include triphenylphosphine, tritolylphosphine, triphenylphosphine, tributylphosphine, and those with the general formula (C ₆ H ₅ ) ₂ P(CH ₂ ) _o P(C ₆ H ₅ ) ₂
Diphosphine represented by (n=1 to 6) may also be used, and these may be used alone or in combination of two or more. In the present invention, the hydroformylation catalyst is hydrogen-treated in the form of a solution in a commonly used organic solvent, and the solvent is generally an aromatic hydrocarbon such as benzene, toluene, xylene, or ethylbenzene, or an aromatic hydrocarbon such as octyl phthalate. aromatic ester,
Other organic solvents known for use in hydroformylation may be used. As for the hydroformylation reaction conditions using the catalyst treated by the method of the present invention, the pressure may be at least atmospheric pressure, but from the viewpoint of productivity and economy 1
The temperature is preferably about 30°C/cm ² . Reaction temperature is 20-200
℃, preferably 50 to 120℃. The rhodium complex catalyst solution to be hydrogen-treated in the present invention can be used as it is after being separated from the aldehyde, which is a hydroformylation product, by a method such as distillation or extraction. Such solutions usually contain large amounts of tertiary phosphine and carbon monoxide, and solid hydrogenation catalysts, which are well known to be easily poisoned by tertiary phosphine and carbon monoxide, cannot be used to treat such solutions. It is unexpected that it can be used repeatedly. That is, by subjecting a hydroformylation catalyst solution whose activity has decreased to hydrogen treatment in the presence of a solid hydrogenation catalyst, the activity of the hydroformylation reaction is restored. In addition, if a rhodium complex catalyst solution that has been used to a certain extent and still shows no noticeable decrease in activity on the surface is passed through the hydrogenation catalyst zone in the same way, it will prevent the accumulation of poisonous substances and prevent a decrease in activity. be done. General hydrogenation catalysts (for example, “Practical Catalysts by Reaction” supervised by Kimio Tarama, P.112~
113;
(Refer to Catalyst Engineering Course Vol. 6, p. 224) Among them, those mainly composed of Group 8 metals such as nickel, cobalt, rhodium, platinum, and palladium are particularly effective in the present invention; It is used as a metal catalyst. In particular, there are metal catalysts mainly composed of nickel and cobalt, and by performing hydrogen treatment in the presence of these metal catalysts, the specific activity of the hydroformylation catalyst can be recovered to nearly 100%. Among Group 8 metals, ruthenium-based hydrogenation catalysts have a small specific activity recovery effect. JP-A-56-28647 discloses a method for stabilizing and regenerating rhodium hydroformylation catalysts by adding cobalt, but cobalt is only used in the form of cobalt carbonyl, inorganic salts, and organic salts, and is not suitable for metal catalysts. This is a completely different technology from the present invention, which involves hydrogen treatment in the presence of hydrogen. The hydrogenation catalyst used in the present invention may be of the Raney type or supported on a carrier such as activated carbon, silica, alumina, diatomaceous earth, or the like. These can be used in a fixed bed if they are in a suspended state or formed into pellets, spheres or granules and filled into a reaction vessel. In the hydrogen treatment, for example, when used in a suspended state, 0.1 to 50%, preferably 1% or more of a hydrogenation catalyst is added to the rhodium complex catalyst solution.
Introduce hydrogen gas so that the amount is Kg/cm ² G, and
The temperature is 150°C, preferably 50 to 100°C. Pressure is 70Kg/
There is no problem in terms of effectiveness if the pressure is higher than cm ² G, but since a high-pressure device is required, a low pressure is preferable. For example, when a dry Raney nickel catalyst is used, hydrogen treatment can be carried out satisfactorily even at normal pressure. After the hydrogen treatment, when the hydrogenation catalyst is used in a suspended state, it can be separated by filtration, decantation, centrifugation, etc. When a hydrogenation catalyst is used as a fixed bed,
These operations are not necessary because it is sufficient to simply flow the rhodium complex catalyst solution under a hydrogen atmosphere. Hereinafter, the present invention will be explained in further detail with reference to Examples.
The method for measuring the catalytic activity is shown in Reference Example 1, and the example of the hydroformylation reaction for obtaining a catalyst with reduced activity used in the Examples is shown in Reference Example 2. Reference example 1 Allyl alcohol in rhodium complex catalyst solution
Add 0.2mol/HBA and conduct the hydroformylation reaction at 1 atm at 30℃ by passing CO and H ₂ gas (CO50%) under stirring, and measure the production rate (mmol/Hr) of 4-hydroxybutyraldehyde (HBA). did. In this way, the activity of the catalyst can be evaluated very easily by conducting the test under conditions where the temperature and concentration are lowered, taking into consideration that the gas diffusion rate does not become rate-determining for the reaction. In the following experiments, as a rhodium complex catalyst solution.
HRh (CO) (PPh ₃ ) ₃ (0.6-2 mmol/) and PPh ₃
(100 to 200 mmol/) was used. Reference example 2 Rhodium complex catalyst solution and allyl alcohol in an amount such that the allyl alcohol concentration is 2 mol/h are mixed and continuously charged at a rate of 1/hr into an autoclave with a liquid volume of 1 until the total pressure is 2 Kg/cm ² G. Carry out the hydroformylation reaction of allyl alcohol by supplying CO, _HH2 gas (CO20-50%) to 65
This was carried out for 4 hours at ℃. During this time, the reaction product was extracted with water and the rhodium complex catalyst solution was circulated to the reactor again. After repeating this reaction 28 times, the activity of the catalyst decreased significantly, and activity measurements showed that the initial HBA
The one whose production rate was 22 mmol/Hr was 0.8
It had become mmol/・Hr. That is, the specific activity (R/R ₀ )=3.6%. Example 1 2 g of dry Raney nickel hydrogenation catalyst was added to 100 ml of the rhodium catalyst solution with reduced activity shown in Reference Example 2.
After hydrogen treatment at 90°C for 2 hours at a hydrogen pressure of 1 Kg/cm ² G, dry Raney nickel was removed by filtration in a nitrogen atmosphere, and the activity of the rhodium catalyst was measured using the method of Reference Example 1. The HBA production rate was 21.7. mmol/
・It was confirmed that the activity was completely recovered. (Specific activity: 99%) Comparative Example 1 100 ml of the rhodium catalyst solution with reduced activity shown in Reference Example 2 was heated to a hydrogen pressure of 50 ml without the presence of a hydrogenation catalyst.
The HBA production rate after treatment at 100° C. for 2 hours at Kg/cm ² G was 8.75 mmol/·Hr. (specific activity 40
%) Examples 2 to 9 0.5 as a hydrogenation catalyst in the same manner as in Example 1
%Pt/activated carbon, 1%Pd/SiO ₂ , Raney Ni (Mo),
Ni(Zr)/diatomaceous earth, Co(Zr)/diatomaceous earth,
The activity of the rhodium catalyst was also recovered when hydrogen treatment was performed using Ni (Cu, Cr)/diatomaceous earth or Rh/activated carbon. The results are shown in Table 1. 【table】

Claims (1)

[Scope of Claims] 1. A method for treating a hydroformylation catalyst, which comprises hydrogenating a rhodium-tertiary phosphine-based hydroformylation catalyst in a solution state in an organic solvent in the presence of a solid hydrogenation catalyst. 2. The treatment method according to claim 1, wherein the hydrogenation catalyst is selected from the group consisting of nickel, palladium, platinum, cobalt and rhodium. 3 Hydrogen treatment conditions are temperature 30℃~150℃, hydrogen pressure 0
70 Kg/cm ² G. The treatment method according to claim 1.