JPH07149684A - Production of aldehydes - Google Patents

Abstract

PURPOSE:To obtain a process for the production of an aldehyde capable of suppressing the degradation of a trivalent organic phosphorus compound in the separation of the reaction product liquid of a hydroformylation reaction. CONSTITUTION:An aldehyde is produced by separating at least one component selected from carbon monoxide, hydrogen, unreacted olefin, produced aldehyde, solvent, by-product having medium boiling point and by-product having high boiling point from a reaction product liquid of a hydroformylation reaction. The retention time of each separating operation is maintained to <=1hr or the operation temperature is maintained to <=180 deg.C and the retention time H (hr) and the operation temperature T ( deg.C) are controlled in such a manner as to satisfy the formula P<=1 wherein P is a value defined by the formula P= H*exp[8000((1/453)-(1/(T+273))0].

Description

Detailed Description of the Invention

[0001]

The present invention relates to the production of aldehydes by reacting an olefin with carbon monoxide and hydrogen (hereinafter referred to as oxo gas) in the presence of a rhodium complex catalyst containing a trivalent organic phosphorus compound as a ligand. From the reaction product liquid, oxo gas, unreacted olefin, generated aldehyde, solvent,
The present invention relates to a method for producing aldehydes in which at least one component selected from a medium boiling by-product and a high boiling by-product is separated.

[0002]

2. Description of the Related Art Conventionally, a method for carrying out a hydroformylation reaction of an olefin in the presence of a rhodium catalyst having a trivalent organophosphorus compound such as triphenylphosphine as a ligand has been known, and has been commercialized worldwide. Has been done. In particular, the organophosphorus compound used in the catalyst solution is usually used in a large excess concentration with respect to rhodium in order to prevent the deactivation of expensive rhodium. Even if the alteration rate of the phosphorus compound is small, a considerable amount of the organic phosphorus compound is lost, and various improvements have been attempted.

For example, JP-A-53-92706 discloses a method for suppressing deactivation of a rhodium catalyst in a hydroformyl reaction, carbon monoxide partial pressure, reaction temperature, T
Although the relationship between the stability factor F calculated using the reaction conditions such as the PP / Rh ratio as a variable and the activity loss rate is disclosed, there is no description about a method for suppressing alteration of the organophosphorus compound.

Further, in Japanese Patent Laid-Open No. 3-66640,
General formula Ar-SH with water-insoluble rhodium complex catalyst
Disclosed is a method for effectively suppressing the decomposition of a phosphorus ligand by performing a hydroformyl reaction in the presence of an arylthiol represented by the formula (wherein Ar represents a substituted or unsubstituted aryl group).

Further, JP-A-52-139012 discloses a method for hydroformylating olefins using a rhodium complex salt catalyst, by continuously stripping the liquid reaction medium to obtain a phosphorus content in the reaction system. Is maintained at a specific value to reduce the loss of organophosphorus compounds by high boiling phosphorus-containing by-products.

[0006]

However, in the method described in Japanese Patent Application Laid-Open No. 3-66640, allylthiol to be added is an inhibitor of the hydroformylation reaction, and monoxide is added to compensate for the decrease in the reaction rate. It is necessary to change the reaction conditions such as increasing the carbon partial pressure or hydrogen partial pressure and increasing the reaction temperature. Changes in these reaction conditions are
This will cause by-products such as alkanes and high-boiling substances, and will also affect the reaction results.

Further, the method described in Japanese Patent Laid-Open No. 52-139012 has a drawback that the loss of the organic phosphorus compound is large due to the organic phosphorus compound being stripped together with the high-boiling substance.

The present invention has been made in view of the above circumstances, and an object thereof is to obtain oxo gas, unreacted olefins, aldehydes produced from a reaction product solution of a hydroformylation reaction.
An object of the present invention is to provide a method for producing aldehydes capable of reducing the alteration of trivalent organophosphorus compounds without adding a substance that inhibits the hydroformylation reaction when separating a solvent, medium-boiling and high-boiling by-products. .

[0009]

Means for Solving the Problems As a result of intensive studies on the above problems, the present inventors have found factors relating to the alteration of trivalent organophosphorus compounds in the separation operation after the hydroformylation reaction, and identified these factors. The present invention has been completed by establishing a method for suppressing alteration of the trivalent organophosphorus compound by controlling based on the equation.

The gist of the present invention is to react an olefin with carbon monoxide and hydrogen in a catalyst solution containing a rhodium complex catalyst containing a trivalent organophosphorus compound as a ligand, a free trivalent organophosphorus compound and a solvent. In the method for producing an aldehyde, after the reaction, at least one component selected from carbon monoxide, hydrogen, unreacted olefin, aldehyde formed, solvent, medium boiling by-product and high boiling by-product is separated from the reaction product liquid, The residence time in each separation operation is maintained at 1 hour or less, or the operation temperature is maintained at 180 ° C. or less, and the equation P = H * exp [8000 ((1/453)-(1 / ( T + 273)))] (where H represents the residence time (hr) and T represents the operating temperature (° C)), the residence time and the operating temperature are adjusted so that the P value becomes 1 or less. Mutual adjustment By resides in a manufacturing method of aldehydes and performing the separation operation.

The present invention will be described in detail below. The catalyst used in the present invention is a rhodium catalyst containing a trivalent organic phosphorus compound as a ligand.

Examples of the trivalent organophosphorus compound that coordinates with rhodium and the free trivalent organophosphorus compound include organophosphorus compounds having the ability as a monodentate ligand or a polydentate ligand. Examples of the organophosphorus compound having a monodentate ligand include tributylphosphines such as tributylphosphine and trioctylphosphine, triphenylphosphines, triarylphosphines such as triarylphosphines in which hydrogen of a phenyl group is substituted with a sulfone group, a halogen or the like. , Alkylcyclophosphine such as tricyclohexylphosphine, monobutyldiphenylphosphine and dipropylphenylphosphine, phosphines such as cycloalkylarylphosphine and alkylcycloalkylphosphine, and phosphites such as triphenylphosphite.

As the organic phosphorus compound having a polydentate ligand, bis (diphenylphosphino) propane, a general formula

[0014]

[Chemical 1]

(R ^{1 to} R ⁴ are an alkyl group, an aryl group, an alkyloxy group or an aryloxy group, and Y is a divalent bridging group. For example, carbonization which may contain oxygen, sulfur, nitrogen or the like. A bisphosphine compound and a bisphosphite compound represented by (for example, a hydrogen group).
Two or more kinds of these trivalent organic phosphorus compounds can be used as a mixed ligand, and a trivalent organic phosphorus compound and a pentavalent organic phosphorus compound such as triphenylphosphine oxide are mixed and used. You can also

As the rhodium source of the rhodium complex catalyst,
Hydride carbonyl tris (triphenylphosphine)
Rhodium, acetoxybis (triphenylphosphine)
Besides rhodium complexes such as rhodium, organic salts such as rhodium acetylacetonate and rhodium acetate, inorganic salts such as rhodium nitrate, oxides such as rhodium oxide and the like can be used.

The rhodium source may be fed directly to the hydroformylation reactor, but outside the reactor together with carbon monoxide, hydrogen and a trivalent organophosphorus compound, elevated temperature in a solvent
The rhodium complex catalyst can be prepared in advance by reacting under pressure. The solvent used in the catalyst preparation is usually selected from the reaction solvent described below,
It does not necessarily have to be the same solvent as the reaction solvent. The preparation conditions are usually such that the rhodium concentration is several ppm to several weight%, and the ratio of the trivalent organic phosphorus compound and rhodium is P / Rh = 10 to 1.
0000 (molar ratio), the temperature is 60 to 200 ° C., the pressure is normal pressure to 200 Kg / cm ² G, and the treatment time is selected within the range of several minutes to several hours. The reaction system for preparing the catalyst may be a batch system or a continuous system.

As the solvent for the hydroformylation reaction, the olefin itself may be used as the solvent, or the aldehyde produced or the high boiling point product produced as a by-product may be used. Also,
Dissolves aliphatic hydrocarbons such as hexane and octane, aromatic hydrocarbons such as toluene and xylene, alcohols such as butanol, octanol, and polyethylene glycol, ethers such as triglyme, esters such as dioctyl phthalate, and catalysts such as water. However, a solvent that does not adversely affect the reaction can be used.

The raw olefin is not particularly limited in kind, and α-olefin or internal olefin is used,
It can be used alone or as a mixed olefin.
The preferred olefin is an olefin having 2 to 5 carbon atoms or a mixture thereof, and the most preferred olefin is propylene. It is also possible to use a raw material having a low purity of olefin such as paraffins and other hydrocarbons.
The raw material olefin is usually used without any special pretreatment, but sulfur, halogen, or diene / trienes, peroxides, etc. which act as catalyst poisons are conventionally known as adsorption, extraction, distillation and heat treatment. Alternatively, those removed by a method such as membrane separation may be used.

The hydroformylation reaction conditions are usually a hydrogen partial pressure of 0.1 to 200 kg / cm ² G, a carbon monoxide partial pressure of 0.1 to 200 kg / cm ² G, and a total pressure of Kg / c.
m ² G to 300 kg / cm ² G, hydrogen partial pressure / carbon monoxide partial pressure = 0.1 to 10, reaction temperature 60 to 200 ° C., Rh concentration of several ppm to several wt%, P (free organophosphorus compound) Order) /
Rh = 10 to 10000 (molar ratio), reaction time several minutes to 1
It is appropriately selected within the range of 0 to several hours.

The olefin hydroformylation reaction is usually carried out by continuously supplying the raw material olefin, oxo gas and catalyst liquid to a continuous reactor, and is carried out under the above hydroformylation reaction conditions. A vessel can also be used.

The by-product having a medium boiling point, which is a by-product of the hydroformylation reaction, means a compound having a boiling point lower than that of the organic phosphorus compound, and is mainly produced by the secondary side reaction of the aldehyde produced in the hydroformylation reaction. is there. For example, in the hydroformylation reaction of propylene, linear n-butyraldehyde and branched isobutyraldehyde are produced, but these aldehyde products are highly reactive and, in the absence of a catalyst, In addition, a polymerization reaction or a condensation reaction is slowly caused even at a relatively low temperature to form a polycondensation product having a medium boiling point.

Examples of these medium boiling point polycondensation products include:
As for n-butyraldehyde, dimers and trimers which are self-polymerization products thereof, 2-ethylhexenal which is a condensation dimer thereof, 2-ethylhexanal and 2-ethylhexanol which are hydrides thereof, and n-butyl. Examples thereof include aldehyde hydride, n-butanol, and n-butyraldehyde dibutyl acetal. Also, from isobutyraldehyde, a dimer or trimer which is a self-condensate is produced in the same reaction as n-butyraldehyde, and a dimer which is an alternating polymerization product of n-butyraldehyde and isobutyraldehyde. , Trimers and their derivatives are also produced.

In the hydroformylation reaction,
In addition to the above-mentioned medium boiling point by-product, a high-boiling point by-product having a boiling point higher than that of the organic phosphorus compound is also by-produced.

The reaction product liquid is withdrawn from the reactor and at least one selected from oxo gas, unreacted olefin, aldehyde formed, solvent, medium boiling by-product and high boiling by-product.
The two components are separated.

As the separation operation, distillation operations such as simple distillation, reduced pressure distillation, thin film distillation, steam distillation and the like, as well as separation operations such as gas-liquid separation, evaporation, gas stripping, gas absorption or extraction can be used.

INDUSTRIAL APPLICABILITY The present invention is applied in a separation operation in the presence of a medium-boiling-point byproduct or a high-boiling-point byproduct which affects the alteration of an organophosphorus compound, and the alteration rate of the trivalent organophosphorus compound in each separation operation. Is the residence time H (hr) and the operating temperature T
It is expressed as a function with (° C.) and has a large dependence on the operating temperature. In the present invention, the residence time is a value obtained by slowing the amount of the retained liquid in each separation operation by the amount of the supplied liquid, and the operation temperature T (° C) means the maximum temperature in each separation operation.

The operating temperature of each separation operation is preferably 180 ° C. or lower, more preferably 20 to 160 ° C. or lower. The residence time is preferably 1 hour or less, more preferably 20 minutes or less.
The operating pressure is 0.1 mmHg to atmospheric pressure.

In the present invention, the influence of the residence time and the operating temperature in each separation operation on the alteration of the trivalent organophosphorus compound is evaluated by the equation defined below. P = H * exp [8000 * ((1/453) -1 / (T + 273))] (In the formula, H represents a residence time (hr) and T represents an operating temperature (° C)) In each separation operation The P value represents the degree of alteration of the trivalent organophosphorus compound and has a substantially linear correlation with the alteration rate. In the present invention, the value of P is 1 or less, preferably 0.00001 to 0.8, and more preferably 0.000.
While adjusting the residence time and the operating temperature to each other within the above range so as to fall within the range of 1 to 0.5, oxo gas, unreacted olefin, generated aldehyde, solvent, medium boiling secondary By carrying out each separation operation of the organism and the high boiling by-product, the alteration rate of the trivalent organic phosphorus compound can be suppressed to 0.5% / day or less.

When each separation operation is carried out under the condition that the value of P becomes larger than 1, the deterioration of the trivalent organic phosphorus compound remarkably increases, which is not preferable. Further, both the residence time and the operating conditions are not preferable because the trivalent organophosphorus compound is significantly deteriorated even when the respective separating operations are carried out under conditions exceeding the above ranges.

That is, by adopting at least one of operating conditions of residence time of 1 hour or less and operating temperature of 180 ° C. or less, and performing each separation operation under the condition that the P value is 1 or less, 3 It is possible to suppress alteration of the valent organophosphorus compound.

Each separation operation in the present invention may be carried out in an independent step, or two or more components may be separated simultaneously. When a high boiling by-product is used as the solvent, the high boiling by-product may be recycled to the reactor after being separated from the product aldehyde under the above operating conditions.

According to the present invention, by adopting the operating conditions satisfying the above conditions, the alteration rate of the trivalent organophosphorus compound is estimated, and further, the construction cost, the manufacturing cost, etc. are comprehensively considered, It is possible to design a plant capable of suppressing alteration of the trivalent organophosphorus compound.

[0034]

EXAMPLES The present invention will now be described in more detail with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

Example 1 A hydroformylation reaction of propylene was carried out using the apparatus shown in FIG. The condition of the catalyst liquid in the pipeline (12) is Rh300m.
g / l, triphenylphosphine (hereinafter referred to as TPP)
About 20 wt% and toluene about 50 wt%. The reactor (3) was maintained at 100 ° C. and a total pressure of 17 kg / cm ² G, and propylene and oxo gas (H ₂ / CO molar ratio of 1 were used to maintain the pressure of the reactor (3) at 17 kg / cm ² ). .0) was replenished. Inerts and some unreacted material were released to the vent. The reaction product liquid was introduced into the countercurrent contact tower (5) through the pipe (4), and the unreacted olefin was stripped by the intimate contact with the oxo gas. The oxo gas from which the unreacted olefin was recovered was circulated to the reactor (3) through the line (14). The reaction product liquid was decompressed in the gas-liquid separator (7), and the generated gas was discharged to the vent. Furthermore, the reaction liquid was introduced into the aldehyde separation column (9) by a pipe (8), and butyraldehyde was separated by distillation (10). Most of the bottoms of the aldehyde separation column (9) was circulated to the reactor (3) as a catalyst liquid, but part of it was introduced to the medium boiling separation column (11) to remove the solvent and the medium boiling by-products. After removal, a part of the high boiling by-product was removed by withdrawing a part of the bottom liquid through the pipe line (13). When the operating conditions in each distillation operation were carried out as shown in Table 1, TPP was carried out.
The alteration rate was 0.18% / day. The alteration rate of TPP is expressed by the mass change of TPP per unit time with respect to the amount of TPP that is maintained constant in the apparatus (the amount of TPP added initially).

Comparative Example 1 The procedure of Example 1 was repeated except that the operating temperature T of the medium boiling separation column (11) was 180 ° C. As a result, TP
The alteration rate of P was 0.61% / day.

Reference Examples 1 to 6 Using a medium boiling point / high boiling point by-product and commercially available toluene, TPP, and HRhCO (TPP) ₃ collected in the Examples, a catalyst solution having the composition shown in Table 2 was placed under a nitrogen atmosphere. And prepared by heating in an autoclave for about 20 hours. Table 2 shows the heat treatment conditions and the TPP alteration rate.

From Reference Example 1, it can be seen that the TPP is hardly denatured in the catalyst solution containing no by-product. Further, it can be seen from Reference Examples 2 and 3 that both the medium boiling point product and the high boiling point product contribute to the alteration of TPP, but the contribution of the high boiling point product is particularly large. Since the reference example is a heat treatment of the prepared catalyst liquid, it is not possible to calculate the P value in the present invention and simply compare it with the alteration rate of TPP.
In order to show the effect of the heating temperature, the P value per one hour of the residence time H (hr) is shown in Table 2 for Reference Examples 4 to 6.

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

EFFECTS OF THE INVENTION By carrying out the separation operation of the hydroformylation reaction product liquid according to the present invention, the alteration of the trivalent organic phosphorus compound is remarkably suppressed, and the aldehydes can be produced industrially advantageously.

[Brief description of drawings]

FIG. 1 shows a flow diagram of an embodiment of the present invention.

[Explanation of symbols]

3: Stirred tank reactor, 5: Countercurrent contact tower, 7: Gas-liquid separator, 9: Aldehyde separation tower, 11: Medium boiling separation tower

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[Procedure amendment]

[Submission date] December 16, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 7

[Correction method] Change

[Correction content]

Claims (9)

[Claims] 1. After reacting an olefin with carbon monoxide and hydrogen in a catalyst solution containing a rhodium complex catalyst containing a trivalent organophosphorus compound as a ligand, a free trivalent organophosphorus compound and a solvent, In the method for producing aldehydes, which separates at least one component selected from carbon monoxide, hydrogen, unreacted olefin, generated aldehyde, solvent, medium boiling by-product and high boiling by-product from the reaction product liquid, Residence time less than 1 hour, or operating temperature 180 ℃
The equation maintained below and defined below: P = H * exp [8000 ((1/453)-(1 / (T + 273)))] (where H is the residence time) (Hr), T represents operating temperature (° C.), and each separation operation is performed by mutually adjusting the residence time and the operating temperature so that the P value when calculated is 1 or less. A method for producing an aldehyde, comprising: 2. The method for producing aldehydes according to claim 1, wherein the separation operation of each component comprises an independent separation step. 3. The method for producing an aldehyde according to claim 1, wherein the separation operation of each component includes a step of separating the generated aldehyde from the reaction product liquid. 4. The method for producing an aldehyde according to claim 1, wherein the separating operation includes steam distillation. 5. The method according to claim 1, wherein the separation operation includes thin film distillation.
The method for producing an aldehyde according to any one of 1. 6. The method for producing aldehydes according to claim 1, wherein the trivalent organic phosphorus compound is triphenylphosphine. 7. The method for producing aldehydes according to claim 1, wherein the olefin is ethylene and the aldehyde produced is propylene. 8. The method for producing an aldehyde according to claim 1, wherein the olefin is propylene, and the aldehyde produced is a mixture of n-butanal and isobutanal. 9. The method for producing an aldehyde according to claim 1, wherein the olefin is butene, and the aldehyde produced is a mixture of straight-chain pentanal and branched-chain pentanal.