JPS58128150A - Activating and regenerating method of catalyst - Google Patents

Abstract

PURPOSE:To activate and regenerative degraded activity by treating catalysts of cobalt-pyridines for hydroester or hydrocarboxylation reaction of unsatd. compds. with an aq. acid soln. in an inert gaseous or CO atmosphere in the presence of liquid hydrocarbon. CONSTITUTION:When the activity of catalysts of cobalt-pyridines to be used in the stage of hydroesterifying or hydrocarboxylating unsatd. compds. contg. carbon double bonds by causing the same to react with CO and alcohol or water degrades, said catalysts are brought into contact with an aq. acid soln. of 0.5g equiv. sulfuric acid, etc. with respect to 1g equiv. total nitrogen compd. (pyridines and changed matter of pyridines) in the catalyst wherein hydrocarbon solvents sufficient for dissolution of cobalt carbonyl, as well as an inert gases and CO atmosphere. Cobalt carbonyl is separated into the hydrocarbon phase and pyridines contg. changed matter of pyridines are separated into the water phase. The catalysts of cobalt-pyridines having high activity is obtained by adding pyridines to the hydrocarbon phase.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses a complex catalyst (hereinafter referred to as a cobalt-pyridine catalyst) composed of a cobalt compound mainly consisting of a coordination compound of cobalt and carbon monoxide and a pyridine. In a method of hydroesterifying and/or hydrocarboxylating an unsaturated compound having a carbon double bond by reacting carbon monoxide with alcohol and/or water, the cobalt-pyridine catalyst whose activity has decreased during recycling is activated. It concerns how to play.

Cobalt b01J catalysts are well known as catalysts for hydroesterification or hydrocarboxylation reactions of unsaturated compounds, but in industrial implementation, it is necessary to recover and reuse the catalysts.

Conventionally, the recovery method for cobalt-pyridine catalysts is as follows:
There are methods such as heating the product to decompose cobalt carbonyl to produce metal cobalt, and treating the product with mineral acids to produce inorganic cobalt salts. These methods not only have complicated processes and operations, but also have the disadvantage that, since activated cobalt is once returned to inactive cobalt, harsh conditions must be used to convert it back to active cobalt when it is recycled and reused.

In addition, in JP-A-50-109886, by mixing hydrocarbons that are normally liquid after the reaction, the hydrocarbon phase containing the reaction product and the cobalt-pyridine catalyst are separated, and the catalyst is recovered and reused. A method is proposed.

This method is an excellent method in which the catalyst can be separated and recovered in an active state and then returned to the reaction system. However, when the recovered catalyst is recycled and used, some of the pyridine bases change during the reaction, producing pyridine derivatives such as piperidines, and these pyridine derivatives form more stable complexes with cobalt. However, it has become clear that the catalyst has a serious drawback in that it rapidly deactivates.

The present inventors have conducted extensive research to establish a method for efficiently and easily reactivating cobalt-pyridine catalysts whose activity has decreased due to the above causes. By treatment with an aqueous solution under an inert gas and/or carbon monoxide atmosphere, cobalt is transferred to the hydrocarbon phase in the form of cobalt carbonyl, and pyridines and hazardous pyridine derivatives are transferred to the acid. It was discovered that salts are formed and selectively dissolved in the aqueous phase, and the present invention was completed as an industrially extremely advantageous activation method.

That is, the present invention provides a method for activating and regenerating a cobalt-pyridine catalyst whose activity has decreased or been deactivated due to the presence of a pyridine derivative, in which a hydrocarbon solvent sufficient to dissolve cobalt carbonyl is present in the catalyst. Cobalt carbonyl is produced by contacting 0.5 gram equivalent or more of an acid aqueous solution per gram equivalent of all nitrogen compounds (the sum of pyridines and pyridine derivatives) under an inert gas and/or carbon monoxide atmosphere. Pyridines containing harmful pyridine derivatives are separated into an aqueous phase, and the hydrocarbon phase is recycled to the reaction system as it is, or at least 1 pyridine per gram atom of cobalt is added to the hydrocarbon phase. .5 gram equivalent of pyridine is added to form a cobalt-pyridine catalyst, which is separated from the hydrocarbon phase and then recycled to the reaction system. It is something.

The hydrocarbon solvent used in the present invention may be any solvent as long as it is incompatible with water and dissolves cobalt carbonyl, such as alkanes and/or sinoloalkanes having 4 to 20 carbon atoms,
Specifically, pentane, hexane, hezotane, decane, tetradecane, cyclohexane, etc., and aromatic hydrocarbons, specifically benzene, toluene, xylene, cumene,
cymen, etc., and the starting unsaturated compounds used in the present invention and mixtures thereof. The amount of hydrocarbon solvent to be used varies depending on the type of hydrocarbon solvent and processing temperature, but the amount that sufficiently dissolves cobalt carbonyl,
That is, more than 1 gram atom of cobalt fi, D 0.5 is required. If the hydrocarbon content is less than 0.5 per gram atom of cobalt, the catalyst cannot be sufficiently dissolved, resulting in a decrease in cobalt recovery. The cobalt recovery rate increases as the amount of hydrocarbon solvent increases, but if the amount is too large, the equipment becomes large and is disadvantageous in industrialization, so preferably 8 or less per gram atom of cobalt is used.

The acid aqueous solution which is an important requirement for carrying out the present invention includes mineral acids such as hydrochloric acid, sulfuric acid, phosphoric acid, etc.
3 organic acids such as formic acid, acetic acid, etc. and mixtures thereof are used. Preferred acids are sulfuric acid and hydrochloric acid. The amount of the acid aqueous solution used is 0.5 gram equivalent or more per gram equivalent of all nitrogen compounds in the catalyst, and preferably,
The amount is 1 gram equivalent or more per gram equivalent of all nitrogen compounds in the catalyst. If the amount of the acid aqueous solution used is less than 0.5 gram equivalent of the total nitrogen compounds in the catalyst, the separation of cobalt in the catalyst from the harmful pyridine derivatives will be insufficient, and the harmful substances will be present in the hydrocarbon phase. is mixed in, and catalyst activation is not achieved sufficiently. On the other hand, the larger the amount of acid aqueous solution, the better the separation of cobalt and harmful substances. However, if the amount is too large, the cobalt recovered in the hydrocarbon phase in the form of cobalt carbonyl will be further decomposed and will flow out into the water phase as cobalt ions and be recovered. 95 per gram equivalent of total nitrogen compounds in the catalyst.
Use in gram equivalent or less. The acid concentration of the acid aqueous solution is not particularly limited, but if the concentration is too low, not only will the amount of acid aqueous solution used increase and the size of the apparatus will increase, but the concentration of pyridines dissolved in the aqueous phase will be diluted. Since this may cause difficulty in recovery, it is preferably used at 1M, 01/'L or more.

There are no particular restrictions on the method of contacting the catalyst with the acid aqueous solution, but since it is a heterogeneous system, the higher the contact efficiency, the shorter the processing time. As a contact method, a rotary blade stirrer, a circulation pump, an inert gas blowing type, a multistage countercurrent contact tower, etc. are generally used.

The atmosphere during the treatment, which is one of the treatment conditions, is an inert gas and/or carbon monoxide atmosphere due to the stability of cobalt carbonyl. Due to the stability of cobalt carbonyl, carbon monoxide is preferably used, and more preferably carbon monoxide is used under a pressure of 1 to 50 W to prevent a decrease in the cobalt recovery rate due to the cobalt ion flowing out into the aqueous phase. I can suppress it.

In addition, the treatment temperature may vary depending on the treatment atmosphere as long as it is below a temperature that maintains the stability of cobalt carbonyl.
7 Generally, it is preferable to carry out the reaction at a temperature of 50°C or lower.

The pyridine of the cobalt-pyridine point catalyst here is a general term for pyridine and its homologues, methyl derivatives such as β-picoline and r-picoline, ethyl derivatives such as 4-ethylpyridine, 2,6- Dimethyl derivatives such as lutidine and 3,4-lutidine; trimethyl derivatives such as r-collidine and β-collidine; and the like. Also, quinoline,
Inquinoline can also be used as a pyridine. Among these, pyridine, r-picoline, and β-picoline are most preferred.

The hydrocarbon containing cobalt carbonyl obtained by the present invention can be returned to the reaction system as it is without any special treatment, or it can be separated from the hydrocarbon phase by adding pyridines to form a cobalt-pyridine catalyst. After that, the initial reaction activity is shown by returning it to the reaction system. In this case, the amount of pyridine added must be at least 1.5 gram equivalent per gram atom of cobalt. If the amount is less than that, the addition will not have any effect.

Also, depending on the acid treatment activation conditions, the resulting hydrocarbon phase may contain trace amounts of nitrogen compounds and acids, so washing with water under an inert gas and/or carbon monoxide atmosphere may remove trace amounts of nitrogen compounds or acids. It is also possible to return it to the reaction system after removing it.

In addition, regarding the cobalt that has leaked into the aqueous phase, the aqueous phase is made alkaline with sodium hydroxide, potassium hydroxide, etc. to precipitate it in the form of cobalt hydroxide, recover it separately, and re-slIg it into cobalt carbonyl before adding it to the reaction system. It is also possible to return it. On the other hand, the pyridines in the aqueous phase can be separated from harmful pyridine derivatives by distillation after neutralization, and recovered and returned to the reaction system.

Although the catalyst activation operation according to the present invention may be performed on the entire amount of the catalyst, it is also possible to maintain the catalyst activity at a partial level by extracting a portion of the catalyst, performing the activation treatment, and returning it to the reaction system. This is an industrially extremely advantageous catalyst activation method.

Examples are shown below to explain the method of the present invention in further detail.

Reference Example 1 Using an autoclave with an internal volume of 54 mm, 6 moles of dicyclopentadiene, 15 moles of methyl alcohol, and r
- Prepare 7.5 moles of picoline and 1.5 moles of dicobalt octacarbonyl and add carbon monoxide to 70? /WI2G''
! After pressurizing at 140° C., the reaction mixture was heated to 140° C. to carry out the reaction.

The reaction was carried out for 2 hours while maintaining the carbon monoxide pressure at 100 to 15 I2G by externally replenishing carbon monoxide consumed by the reaction. Thereafter, the reaction temperature was raised to 160°C, and the reaction was continued for an additional 2 hours.

After cooling, the carbon oxide was removed, and cyclohexane 4 was introduced into the reaction mixture. After stirring, the catalyst layer was separated into a lower layer, and the reaction product and catalyst were separated. Each component was added to the separated catalyst in such a manner that 2 moles of dicyclopentadiene, 5 moles of methanol, and 2.5 moles of r-picoline per 1 gram atom of cobalt were reacted in the same manner.

When the above operation was repeated and the catalyst was circulated 8 times, Table 1
As shown, the yield of dimethyl tricyclodecanedicarboxylate decreased from 81 to 19.

Example 1 Cobalt in the catalyst with reduced activity obtained in Reference Example 1, r
Analysis of -picoline and r-picoline derivatives revealed that 1.8 gram atoms of cobalt and r-
It contained 1.7 moles of picoline and 1.8 moles of r-picoline derivatives.

1 kg of the catalyst was introduced into cyclohexane 5 under nitrogen, and while stirring, 600 mj of a 6 Mot/L H2SO4 aqueous solution corresponding to about 2 g equivalent of the total nitrogen compound was added dropwise at room temperature over 1 hour, and the mixture was stirred for about 1 hour. When the mixture was re-applied, it was separated into a cyclohexane phase and an aqueous phase.

Analysis of the cobalt and nitrogen compounds in the cyclohexane phase revealed that it contained 1.5 grams of cobalt with a cobalt recovery of 85 grams and no nitrogen compounds were detected.

3.0 mol of r-picoline was added to the cyclohexane phase under nitrogen, and after separation from the cyclohexane phase in the form of a cobalt-r-picoline complex, 2 mol of ntadiene per gram atom of cobalt and 5 mol of methanol were added to the catalyst. Add each component to make 2.5 moles of r-Picorif,
The reaction was carried out in the same manner as in Reference Example 1. The reaction results were as shown in Table 1, and the catalyst showed a value almost equal to the initial activity.

Example 2 The acid treatment activation operation of Example 1 was carried out at a carbon monoxide pressure of 20 kg/
It was carried out under 1yR2G.

Cobalt in the cyclohexane phase contained 1.7 gram atoms (94% cobalt recovery) and no nitrogen compounds were detected.

When cobalt was separated from the cyclohexane phase as an r-picoline complex and used in the reaction in the same manner as in Example 1,
As shown in Table 1, the activity was almost the same as the initial activity.

Example 6 Cyclohexane phase 1 containing cobalt carbonyl obtained during the acid treatment of Example 1 (containing 0.3 g atom of tc cobalt), 0.6 mol of dicyclopentadiene, 1.5 mol of methanol, 0 r-picoline Pour .75 mol into a 2t autoclave, -701!4732G with carbon oxide
After pressurizing the mixture to 140° C., the mixture was heated to 140° C. and reacted for 2 hours.

Thereafter, the reaction temperature was raised to 160°C, and the reaction was continued for an additional 2 hours.

During the reaction, add carbon oxide from outside to raise the carbon monoxide pressure to 10
It was maintained at 0Q/m2G. As the results are shown in Table 2, c
It showed the same activity as when o2(co)s/cyclohexane was used as a catalyst.

Comparative example 1 The acid treatment and activation operation of Example 1 was carried out in air.

The cobalt in the cyclohexane phase is 0.76 g atom (
It contained only cobalt (cobalt recovery rate: 42%), most of which was decomposed into the form of cobalt salts and leaked into the aqueous phase.

Comparative Example 2 In the acid treatment activation operation of Example 1, an aqueous H2SO4 solution of 6Mo17'j was carried out using 120 - equivalent to 0.4 gram equivalent of the total nitrogen compound.

The cobalt in the cyclohexane phase contains 0.2 gram atoms (cobalt recovery 11%) and 8.4 moles of nitrogen compounds (nitrogen compound loading 24 g). In addition, a third phase was formed in addition to the cyclohexane phase and the aqueous phase, and most of the cobalt and nitrogen compounds were contained in this phase, and the third phase did not exhibit any reaction activity.

Table 1 +1 Gas chromatography analysis Kaoru 2 Methyl tricyclodecenecarboxylate %3 Dimethyl tricyclodecanedicarboxylate Table 2

Claims (1)

[Scope of Claims] (1) In the hydroesterification reaction and/or hydrocarboxylation reaction of unsaturated compounds, a cobalt-pyridine catalyst with reduced activity containing a pyridine derivative is treated with an inert gas and/or monoxide. cobalt by contacting the catalyst with an acid aqueous solution containing 0.5 or more gram equivalents per gram equivalent of total nitrogen compounds in the catalyst in a hydrocarbon solvent of 0.5 or more per gram atom of cobalt under a carbon atmosphere. Either the carbonyl is separated into the hydrocarbon phase and the pyridines containing the pyridine derivatives are separated into an aqueous phase, and the hydrocarbon phase is recycled to the reaction system as is, or at least 1 carbonyl per gram atom of cobalt is added to the hydrocarbon phase.
．． A method for activating and regenerating a cobalt-pyridine catalyst, which comprises adding 5 gram equivalents of pyridine to form a cobalt-pyridine catalyst, separating it from the hydrocarbon phase, and then recycling it to a reaction system. (2) - The activation regeneration method according to claim (1), which comprises contacting with an acid aqueous solution in an atmosphere of 1 to 50 kg/cM2 of carbon oxide. (8) The activation regeneration method according to claim (1), wherein 1 gram equivalent of all nitrogen compounds in the catalyst is brought into contact with an acid aqueous solution in an amount of 1 gram equivalent or more.