JPS59115752A - Method of reactivating hydroformylation catalyst - Google Patents

Abstract

PURPOSE:To perfectly reactivate the catalyst in mild conditions by using a method for processing the titled Rh and phosphine type catalyst lowered in activity with boron hydride followed by removal of basic substances. CONSTITUTION:The Rh and phosphine type hydroformylation catalyst soln. lowered in activity is processed with boron hydride. Basic substances are usually produced in the system by this treatment, and becomes a factor again deactivating the catalyst, so the treated soln. of the catalyst is washed with water till the washing water rises to 7 pH to remove said basic substances. The washed catalytic soln. is sent to the hydroformylation reactor, and this catalyst is perfectly reactivated and it can be used for a long term.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a treatment method for restoring the high activity of a rhodium-containing hydroformylation catalyst.

Rhodium phosphine 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, but on the other hand, when this catalyst is used for a long time, oxygen, halogens, sulfur, etc. are contained in the raw gas liquid. There is a problem in that it is poisoned by trace components, oxidized by-products such as organic acids, aldehyde condensates, etc., and its activity is significantly reduced or substantially inactivated.

For example, in the hydroformylation of allyl alcohol, a significant decrease in activity as shown in Reference Example 2 was observed.

Therefore, as a result of various studies on activity recovery methods, the present inventors found that by treating a rhodium-phosphine-based hydroformylation catalyst (hereinafter referred to as rhodium complex catalyst) solution with a boron hydride compound and then removing the basic substance, The present invention was completed based on the discovery that the activity could be completely recovered under mild conditions.

As a method for activating and regenerating a rhodium complex catalyst, a method of heating under pressure of hydrogen (Japanese Patent Publication No. 48-43799) is known. In this example of the prior art, the catalyst activity expressed as the butyraldehyde yield is converted into a rate rating to determine the specific activity (K/Ko) relative to the initial value (Ko), which is 36%.
The catalyst reduced to 70 kg / 60 ° C for 14 hours
This is due to the fact that J was recovered to 53% by treatment under hydrogen pressure, but complete recovery to the initial activity may have been achieved.

However, by using the method of the present invention which involves treatment with a borohydride compound, the hydroformylation catalyst can be completely restored to a specific activity of about 100 parts.

Moreover, as can be seen in the examples, the treatment does not require pressurization and is extremely simple and effective in a short period of time.

Maintaining the activity of the hydroformylation catalyst for a long time is
This is an extremely urgent issue, and several proposals have already been made for refining raw materials and maintaining and separating the catalyst liquid as a means other than restoring the activity through catalyst treatment, but in the end, the deactivated catalyst liquid is not returned to manufacturers. (See Catalyst Vol. 23, p. 174), and a simple and effective activity recovery treatment method like the present invention has not yet been realized. However, the substance may differ significantly depending on the target of hydroformylation. JP-A-55-106545 describes the close relationship between activity and color of rhodium catalysts used in the hydroformylation of unsaturated compounds such as alpha-olefins. That is, a fully active rhodium catalyst complex is usually straw-colored, while a deactivated complex is said to be black. but,
In the case of the hydroformylation of allyl 7/L, the catalyst deactivation caused no change in color (no change in color, maintaining the same yellow and transparent state as the active catalyst solution) to a significantly short period of use. Only the activity is lost.

Hydroformylation of allyloxy compounds such as allyl alcohol and allyl acetate is an important step in the process of obtaining butanediols, and deactivation in such a short period of time without any color change is a problem, and the activity It is desired to develop a simple method for preserving or regenerating the

As a result of examining the causes and countermeasures for such disqualification, the present inventor found that allyloxy compounds such as allyl alcohol and allyl acetate coordinate extremely strongly to rhodium complexes through the υ and totsu of hydroformylation products. We have come to believe that this method produces impurities and therefore brings about a deactivation state that is completely different from the hydroformylation of general olefin compounds.

This is schematically shown as follows.

A OCH2C, f (= CFf 2 → A OCH2C
I-I CHO-)C,F(3 CF■3 where A is a hydrogen atom, an acyl group such as an acetyl group, an alkyl group such as methyl or ethyl, an aryl group such as a phenyl group, or an allyl group, AOH means a group that is easily eliminated in the form of

The present invention can completely restore catalyst activity even from deactivation caused by such a strong deactivating substance. Furthermore, a trace amount of H2S contained in synthesis gas acts as a general catalyst poison and causes a long-term decrease in activity, but the present invention is also effective in recovering from such deactivation.

JP-A No. 55-106545 describes that many methods have been tried for regenerating rhodium catalysts used in the hydroformylation of unsaturated compounds such as α-olefins, and according to this, a methanol solution of sodium borohydride is used. The numerous methods listed, including treatment of the deactivated catalyst with a reducing agent such as a hydrazine solution in ethanol, have all been found to be unsatisfactory.

However, the inventor of the present invention was not discouraged by this fact and decided to investigate further (
As a result of our investigation, we surprisingly discovered that the treatment with a boron hydride compound, which had been previously attempted and abandoned above, was an effective activity recovery method only if it was accompanied by the subsequent removal of basic substances. The invention has been completed.

The rhodium complex catalyst used in the present invention was
0730, which is known from Japanese Patent Publication No. 53-17573, etc., and HRh(CO)(P&)3. Rh(Co)2 (acetylacetonate), Rh4(Co)+2. Rh6
Co, such as rhodium carbonyl such as (Co)+i,
H2, HRh(Co)(
Anything that can be converted to PH1)3 can be used as a catalyst.

Examples of the tertiary phosphine represented by PH1 include triphenylphosphine, tritolylphosphine, triphenylphosphite, tributylphosphine, and the general formula (
C6F-15)2P(CHJTLP(Cel5)2T
Diphosphines represented by L=1 to 6 are also used, and these may be used alone or in combination of two or more.

Furthermore, it may contain phosphine oxide, which is an oxidation product of these tertiary phosphines.

In the present invention, the hydroformylation catalyst is treated in the form of a solution in a commonly used organic solvent, and the solvent is benzene,
Aromatic hydrocarbons such as toluene, xylene, and ethylbenzene are commonly used, but aromatic esters such as octyl phthalate, sono, and other organic solvents known for use in hydroformylation are also used.

Hydroformation using the catalyst treated according to the present invention is sufficient, but from the viewpoint of productivity and economy, the concentration is 1 to 30 ICg/c4.
Approximately G is preferable. The reaction temperature is 20-200°C, preferably 50-120°C.

Boron hydride compound treatment may be applied to catalyst solutions containing conventional rhodium complex catalysts as described above.

Since the aldehyde, which is a hydroformylation product, reacts with the borohydride compound, the catalyst in the hydroformylation reaction solution should be brought into contact with the borohydride compound after most of the aldehyde has been separated by methods such as distillation or extraction. is preferred. However, the presence of aldehyde only increases the amount of borohydride compound required and does not pose a decisive hindrance to the practice of the present invention. In fact, the present invention has been carried out on catalyst solutions containing several tens of moles of residual aldehyde as the rhodium catalyst, which is extremely advantageous from an industrial perspective.

The most easily available and inexpensive boron hydride compound is sodium borohydride (NaBFL), which is preferably used in the present invention. NaBH4 is a solution containing an alkali that has the effect of inhibiting decomposition (
Water, alcohol) may also be used.

Other KBH4 puedo BI3 or BH (OCHa
) Anionic metal salts of groups Ia, Ha, IJIa, and iVa having a hydrogen atom directly bonded to boron such as 3 are used.

As a treatment method, the borohydride compound is added to the catalyst liquid with reduced activity in solid form, or water, alcohols such as methanol, ethanol, propatool, monoglyme, diglyme, triglyme, or tetraglyme C) T3 (OCI). (2C[L+)+-+OCHa
It can also be added as a solution dissolved in ethylene glycol derivatives such as dimethylformamide, etc.

Solvents with active hydrogen such as water and alcohol are NaBf (a
Since it gradually reacts with other substances such as hydrogen and generates hydrogen, it is best to use it at a temperature where the activity as a hydrogen boron compound will not decrease. It may be added as an aqueous solution, dispersed by stirring, etc., and brought into contact with the catalyst solution, but if an organic solvent such as alcohol is used, the treatment can be carried out in a homogeneous phase.

The amount of the boron hydride compound added is usually equal to or more than the rhodium contained in the veradium complex catalyst solution to be activated. When the catalyst solution contains an aldehyde, it is preferable to use a larger amount, for example, an amount equal to or more than the sum of rhodium and aldehyde, taking into consideration the consumption of the borohydride compound by the aldehyde.

When a rhodium complex catalyst comes into contact with oxygen, rhodium and tertiary phosphine are oxidized, so treatments such as hydrogen, helium, argon methane, hydrogen, carbon oxide gas, or a mixture of these gases may have an adverse effect on the rhodium complex catalyst. Carry out the test in an atmosphere that does not cause any harmful effects.

As for the treatment temperature, normal temperature is sufficient, or there is no problem even if the treatment is carried out at a temperature of 0 to 80°C.

Although the treatment time depends on the degree of activity reduction, it is usually 1 to 300 minutes, and in most cases, 10 to 120 minutes is enough to achieve a sufficient treatment effect.

When treated with borohydride compounds, basic substances are usually produced in the system. For example, sodium borohydride yields sodium metaborate.

The present invention is characterized in that the basic substances are removed after the borohydride compound treatment, recognizing that such basic substances cause the activity of the regenerated catalyst to decrease again. For example, 1. The rhodium complex catalyst solution after treatment may be washed with water one or more times, preferably until the pH of the washing solution reaches 7. By feeding the water-washed catalyst solution directly into the hydroformylation reactor, it can be used for a long period of time as a catalyst whose activity has been completely recovered.

It is possible to remove the basic substance by methods other than washing with water, such as cation exchange and adsorption, but this is not preferable if it causes loss of rhodium. m1IJ! in a toluene solution of the catalyst! l
! Other basic substances can also be removed using a paper filter. This is considered to be immobilization removal due to reaction with cellulose.

In the field of rhodium complex catalysts, CIRh(CO)(P
It is known to use sodium borohydride or a KOH alcohol solution as a reducing agent for converting rhodium compounds containing chlorine, such as Ph3)3, into hydrides. However, this reaction is completely different from the objective of the present invention, which is to recover the activity of a catalyst solution that has lost its activity due to the continuation of the hydroformylation reaction. In fact, in the reaction of producing hydrides from chlorine compounds, when treated with alkali in alcohol, which is used similarly to NaBH4, the activity does not recover but rather decreases.

In addition, the present invention is not just a reduction treatment, but also a unique one, since other hydrides such as CaH2 and LiA IH4, which generally have a higher temperature reduction ability than NaB and H4, have no effect on restoring the catalytic activity. It shows that it is something like that.

Hereinafter, the present invention will be explained in further detail with reference to Examples.

The method for measuring the catalyst activity was as shown in Reference Example 1, and a catalyst with reduced activity was obtained which was subjected to a boron hydride compound treatment.

An example of the hydroformylation reaction is shown in Reference Example 2.

In addition, in the following experiments, HR was used as the rhodium complex catalyst solution.
h (CO) (PRh3)30.6-6-2rn l
A toluene solution containing PRb3 (100 to 200 mmol/l) and PRb3 (100 to 200 mmol/l) was used.

Reference example 1 Allyl alcohol 01mol/1 in 0dium complex catalyst solution
Add ``W, press Co, H2 gas (CO50%)
The activity of the catalyst was evaluated by carrying out the hydroformylation reaction at 1 atm at 60° C. and measuring the reduction rate constant AHr-1) of allyl alcohol.

Reference example 2 Odium complex catalyst liquid and allyl alcohol concentration are 14-3
．． Mix allyl alcohol in an amount of 5 mol/1,
95-22. The liquid was continuously charged into a bubble column reactor with a liquid volume of 60 stones at a rate of 1/Hr, and the total pressure was 1.6-2.
The hydroformylation reaction of allyl alcohol is carried out at 55-75 °C by supplying Co and H2 mixed gas (CO16-27%) so that OIcg/c, f.1.The reaction product is extracted with water. , the rhodium complex catalyst liquid was circulated to the reactor again. After this reaction was carried out for 90 days, the reaction was stopped and the catalyst solution taken out had an initial activity of 29 to 3. What used to be OHr,
12~], 3 Hl-''-1.

30 mmol/1 aldehyde remains in this catalyst solution.

Example 1 Catalyst liquid 10 was added to the rhodium with reduced activity shown in Reference Example 2.
Add 100 ml of a 50 mmol/l 9 degree aqueous solution of sodium borohydride to 0-, and heat at 150 degrees under a nitrogen atmosphere.
The mixture was stirred at C for 2 hours. 100y of rhodium catalyst liquid after treatment
The product was washed three times with water in step d, and the activity was measured by the method of Reference Example 1. K = 3. OHr-', indicating that the activity had been completely recovered. The amount of NaBH4 used was about 1.6 times (molar ratio) the total amount of aldehyde and rhodium in the catalyst solution.

Example 2 Boron hydride) The concentration of IJium aqueous solution was 10 mm
The same treatment as in Example 1 was carried out except that the molar ratio of rhodium to aldehyde (l/l) was 0.32), and as a result, K=2.4 Hr.

Example 3 The same treatment as in Example 2 was performed except that the treatment temperature was 60° C., and the result was K = 2.41.

Example 4 A rhodium catalyst solution with reduced activity obtained by the same reaction and water extraction as in Reference Example 2 (residual aldehyde 7 mmol/l)
) 100rd and the atmosphere was a CO/H2 mixed gas, the same treatment as in Example 1 was performed, and as a result, K=
It took 2.9 hours. The amount of NaBH4 used was about 62 times (molar ratio) the total amount of aldehyde and rhodium in the catalyst solution.

Example 5 Treatment was carried out in a homogeneous system using 10 ml of an ethanol solution of sodium borohydride at a concentration of 500 mmol/]
Yes. Other conditions are the same as in Example 4. The reaction rate constant after treatment is KM4=3. It was OHr'.

Example 6 An ethanol solution of 1-'Jium boron hydride at a concentration of 200 mmol/1 was prepared using the same treatment as in Example 5 except for the rhodium complex catalyst. As a result, KM4 = 2.8
It was Hr.

Example 7 A rhodium catalyst solution with reduced activity obtained by the same reaction and water extraction as in Reference Example 2 (residual aldehyde 7 mmo 1/
1) An ethanolic solution of sodium borohydride at a concentration of 200 mrnol/l to 5.0 molar ratio of Na B H4 to 250-(Ro)ium→-aldehyde 1.
2 times) at 25°C under a CO/H2 mixed gas atmosphere.
Stir for hours. After treatment, it was washed 11 times with the same volume of water, and the activity was measured using the method of Reference Example 1.
It was IIr.

Using Conorhodium IQJr H, mix allyl alcohol in an amount of 2 mol/l, and add this liquid to 05A/H.
Volume reduction at a speed of r1. 3 5 - was continuously charged into the bubble column reactor in 3, and CO and H2 gases (CO20%) were supplied so that the total pressure was 3 tcg 7 cA, and the hydroformylation reaction of allyl alcohol was carried out at 65 °C. The reaction product was extracted with water, and the rhodium complex catalyst solution was circulated to the reactor again. This reaction was continued for 100 hours, but the conversion rate of allyl alcohol was maintained constant at 98%, and when the activity was measured by the method of Reference Example 1, no change was found from the initial stage.

In this way, it has become clear that even a rhodium complex catalyst whose activity has been significantly reduced can easily recover completely and maintain its activity by treatment with boron hydride.

Example 8' The same treatment as in Example 5 was carried out except that dimethylformamide was used instead of ethanol. As a result, the activity was 3.
The patient developed IHR and made a complete recovery.

Example 9 50 Biao of an aqueous solution containing 7% sodium borohydride and 245% sodium hydroxide was added to 100 ml of the same rhodium catalyst solution with reduced activity as that used in Example 4, and the mixture was stirred at 20°C for 2 hours under a nitrogen atmosphere. did. After the treatment, the rhodium catalyst solution was washed three times with 875-g water and the activity was measured, and it was found that K = 2. 9, and the activity was recovered without any problem even in a high concentration borohydride solution containing sodium hydroxide. It should be noted that the ratio of boron hydride used in this study to IJium hydroxide is the same as the 12% + 42% aqueous solution from the NaBH4 production process, making it economical. be.

Example 10 To 100 ml of the same rhodium catalyst solution with reduced activity as used in Example 4, sodium borohydride was added in solid form and stirred at 20'C for 2 hours under nitrogen atmosphere. After the treatment, the solid sodium borohydride was removed by filtration, and the rhodium catalyst solution was washed three times with 86 g of water.The activity was measured to be -28, and even if a solid state borohydride compound was used, the rhodium catalyst solution was washed with 86 g of water three times. Activity has fully recovered.

Example 11 When hydrogen sulfide was added to the rhodium catalyst liquid 100-100, which had not decreased its activity, in an equimolar amount to the rhodium contained in the catalyst liquid, the activity decreased from -25 to -08. . By subjecting this catalyst solution to the same treatment as in Example 1, the activity became -25, completely recovered.

Comparative Example 1 The same treatment as in Example 1 was carried out except that sodium hydroxide was used instead of sodium borohydride. As a result, the activity was 0.24 Hr, which was actually lower.

Comparative Example 2 The same treatment as in Example 1 was carried out except that hydrazine was used instead of sodium borohydride. As a result, the active member - =
1. Of■r, I had not recovered at all.

Comparative Example 3 The same treatment as in Example 10 was carried out, except that lithium aluminum rhamnohydride was used instead of sodium borohydride. As a result, the activity was 12 hours, with no recovery at all.

Comparative Example 4 The same treatment as in Example 1o was carried out except that calcium hydride was used instead of sodium borohydride. As a result, the activity was 0.98 Hr, and no recovery was observed at all.

patent applicant Daicel Chemical Industries, Ltd.

Claims (1)

[Claims] (11) A method for restoring the activity of a hydroformylation catalyst characterized by treating a rhodium-phosphine-based hydroformylation catalyst solution whose activity has decreased with a boron hydride compound and then removing the basic substance (2) ) The method according to claim 1 for treating a catalyst with reduced activity for use in a hydroformylation reaction of an allyloxy compound.