JP4835228B2 - Method for producing aldehyde - Google Patents

Description

  The present invention relates to a method for producing an aldehyde, and more particularly to a method for producing an aldehyde by subjecting an olefin to a hydroformylation reaction with carbon monoxide and hydrogen in the presence of a catalyst.

  Production of aldehydes using olefinic unsaturated compounds as raw materials has been carried out industrially on a large scale. Specifically, olefinic unsaturated hydrocarbons are reacted with carbon monoxide and hydrogen (hydroformylation reaction) in the presence of a hydroformylation catalyst such as a rhodium catalyst to contain the corresponding linear and branched aldehydes. A hydroformylation reaction product liquid is obtained. Usually, the reaction product solution is separated into an aldehyde-containing solution, a high-boiling product, a light-boiling product, a reaction solvent, and a mixture of hydroformylation catalyst (hereinafter referred to as catalyst solution), and the catalyst solution is returned to the hydroformylation reaction system. Used in circulation.

  Since the phosphite ligand used as the ligand of the hydroformylation catalyst has a high molecular weight, its solubility in the catalyst solution is extremely low. Therefore, unless suitable process conditions for the catalyst solution are found, the concentration of the phosphite ligand in the catalyst solution exceeds the saturation solubility and precipitates in the catalyst solution. It means a large loss, and the economic loss of the process is large.

It is known that phosphite ligands have lower solubility in catalyst solutions than phosphine ligands that have been widely used industrially. For example, in JP-A-6-166694, a specific bisphosphite compound described in the publication has a higher molecular weight and lower volatility than a conventional phosphorus ligand, and has low solubility in a hydroformylation reaction medium. It is described that it is a useful ligand for homogeneously catalyzed hydroformylation of olefinically unsaturated compounds. However, nothing is said about the process conditions for preventing the phosphite ligand from precipitating in the catalyst solution. Japanese Patent Application Laid-Open No. 2001-163821 describes that the catalyst movement path downstream of the reactor is less than 100 ° C., which is intended to minimize the decomposition of the catalyst. The temperature condition is not set focusing on prevention of precipitation. Japanese Patent Laid-Open No. 2002-161063 also describes cooling the circulating catalyst temperature to 40 to 90 ° C., but it is an object to suppress a decrease in catalyst activity. Furthermore, Japanese Patent Application Laid-Open No. 2000-229906 describes that the catalyst solution is separated from the reaction mixture so that the aldehyde concentration is 0.5% by weight or more and is recycled in the reaction zone. The purpose is to reduce the poisoning of the rhodium complex catalyst by the organic phosphonate produced by the decomposition of the organic phosphite. Neither method describes the precipitation prevention of phosphite ligands.
JP-A-6-166694 Japanese Patent Laid-Open No. 2001-163821 JP 2002-161063 A JP 2000-229906 A

  Strict control of process conditions may not cause phosphite ligand precipitation, but if process factors that affect the solubility of the phosphite ligand in the catalyst solution change, There may be phytoligand precipitation problems. For example, if the composition of the catalyst solution is changed or the ratio of separation into the aldehyde-containing solution and the catalyst solution is changed, the phosphite ligand may be precipitated in the catalyst solution. Therefore, it is desirable to find process conditions in which no phosphite ligand is precipitated in the catalyst solution.

  An object of the present invention is to provide a method for producing an aldehyde in which a phosphite ligand is not precipitated in a catalyst solution even when a phosphite ligand having low solubility in a catalyst solution of a hydroformylation reaction is used. That is.

  As a result of intensive studies to solve the above problems, the present inventors have determined the process conditions of the catalyst liquid that is separated from the hydroformylation reaction product liquid and reused, more specifically, the separation ratio of the reaction product liquid and By controlling the components of the catalyst solution and controlling the temperature of the catalyst solution to be circulated in the hydroformylation reaction step, it is possible to prevent precipitation of phosphite ligands having low solubility in the catalyst solution of the hydroformylation reaction. The headline and the present invention were completed.

  That is, the gist of the present invention is a reaction product obtained by hydroformylation reaction in a method for producing a corresponding aldehyde by hydroformylating an olefinic unsaturated compound in the presence of a metal-phosphite ligand complex catalyst. The aldehyde-containing liquid (A) containing no catalyst and containing an aldehyde, the aldehyde and / or a compound having a lighter boiling point than the aldehyde, and the total content of the aldehyde and the compound having a lighter boiling point than the aldehyde is 20 The catalyst solution (B) containing at least wt% and containing the catalyst is separated at a ratio of aldehyde-containing solution (A): catalyst solution (B) = 5: 1 to 1: 5 (weight ratio). And a method for producing an aldehyde, characterized in that the catalyst liquid (B) is maintained at 40 ° C. or higher and circulated in the hydroformylation reaction step.

  ADVANTAGE OF THE INVENTION According to this invention, even if it uses the phosphite ligand with low solubility to the catalyst liquid of hydroformylation reaction, the manufacturing method of the aldehyde which does not precipitate a phosphite ligand in a catalyst liquid is provided. be able to.

Hereinafter, the present invention will be described in detail. In addition, description of the component requirement described below is an example (representative example) of the embodiment of this invention, and is not specified by these content.
In the present invention, an olefinically unsaturated hydrocarbon is reacted with carbon monoxide and hydrogen in the presence of a metal-phosphite ligand complex catalyst to form a hydroformylation containing the corresponding linear aldehyde and branched aldehyde. A reaction product solution is obtained.

  As the olefinic unsaturated hydrocarbon, a linear or branched α-olefin or an internal olefin is usually used, preferably an olefin having 2 to 8 carbon atoms, specifically ethylene, propylene, 1 -Butene, 1-hexene, 1-octene, 1-dodecene, 1-tetradecene and the like can be mentioned, and ethylene, propylene or 1-butene is more preferable. A particularly preferred olefin is propylene.

  Any metal-phosphite ligand complex catalyst may be used as long as it is formed from a metal and a phosphite ligand capable of forming a complex with the metal and functions as a catalyst for the hydroformylation reaction. The metal is not particularly limited as long as it is known to be used for this purpose. For example, an eighth metal such as Co, Rh, Ir, Pd, Pt, Os, or Ru (eighth in the present invention). Metal is a group metal in the periodic table of 1983 and a metal of group 8 to 10 in the current periodic table), and has a high reaction activity as a catalyst for hydroformylation reaction. , Preferably Co, Ru, Rh, Pd, Pt, more preferably Co, Rh, particularly Rh. Although it does not restrict | limit especially as a metal compound which is a metal source, For example, cobalt chloride, cobalt acetate, palladium chloride, palladium nitrate, ruthenium chloride etc. are mentioned, Preferably rhodium compounds, such as rhodium acetate, rhodium trichloride, and rhodium nitrate More preferably, rhodium acetate is used.

  The organic phosphite ligand may be either a monodentate ligand or a polydentate ligand, and the type of the phosphite ligand is not particularly limited. Specific examples of the phosphite ligand include compounds represented by the following general formulas (1) to (10).

(In the general formula (1), R ^{1 to} R ³ each independently represents a monovalent hydrocarbon group which may be substituted.)
Examples of the monovalent hydrocarbon group which may be substituted include an alkyl group, an aryl group, and a cycloalkyl group. Specific examples of the compound represented by the formula (1) include, for example, trimethyl phosphite, triethyl phosphite, n-butyl diethyl phosphite, tri-n-butyl phosphite, tri-n-propyl phosphite, tri-n. -Trialkyl phosphites such as octyl phosphite and tri-n-dodecyl phosphite; triaryl phosphites such as triphenyl phosphite and trinaphthyl phosphite; dimethylphenyl phosphite, diethylphenyl phosphite, ethyl diphenyl phosphite and the like And alkylaryl phosphites. Further, for example, bis (3,6,8-tri-t-butyl-2-naphthyl) phenyl phosphite and bis (3,6,8-tri-t-butyl- 2-naphthyl) (4-biphenyl) phenyl phosphite or the like may be used. Most preferred among these is triphenyl phosphite.

(In the general formula (2), R ⁴ represents a divalent hydrocarbon group which may be substituted, and R ⁵ represents a monovalent hydrocarbon group which may be substituted.)
The divalent hydrocarbon group which may be substituted includes an alkylene group which may contain an oxygen, nitrogen, sulfur atom, etc. in the middle of the carbon chain; an oxygen, nitrogen, sulfur atom, etc. in the middle of the carbon chain. A divalent aromatic group such as phenylene or naphthylene; a divalent aromatic ring bonded directly or in the middle through an atom such as an alkylene group, oxygen, nitrogen or sulfur. Aromatic groups: those in which a divalent aromatic group and an alkylene group are bonded directly or in the middle through atoms such as oxygen, nitrogen, sulfur and the like. Examples of the monovalent hydrocarbon group which may be substituted represented by R ⁵ include an alkyl group, an aryl group and a cycloalkyl group.

Examples of the compound represented by the general formula (2) include neopentyl (2,4,6-t-butyl-phenyl) phosphite, ethylene (2,4,6-t-butyl-phenyl) phosphite and the like. And the compounds described in U.S. Pat. No. 3,415,906.
In addition, the following general formula (3)

(In the general formula (3), R ¹⁰ has the same meaning as R ⁵ in the general formula (2), Ar ¹ and Ar ² each independently represent an optionally substituted aryl group, and x And y each independently represents 0 or 1, and Q represents a group consisting of —CR ¹¹ R ¹² —, —O—, —S—, —NR ¹³ —, —SiR ¹⁴ R ¹⁵ —, and —CO—. R ¹¹ and R ¹² each independently represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a phenyl group, a tolyl group or an anisyl group, and R ¹³ , R ¹⁴ and R ¹⁵ are Each independently represents a hydrogen atom or a methyl group, n represents 0 or 1), more specifically 1,1′-biphenyl-2,2′-diyl- (2,6 -Di-t-butyl-4-methylphenyl) phosphite No. 4599206 and 3,3′-di-t-butyl-5,5′-dimethoxy-1,1′-biphenyl-2,2′-diyl (2-t-butyl-4-methoxyphenyl) And compounds described in U.S. Pat. No. 4,717,775 such as phosphite.

(In the general formula (4), R ⁶ represents a cyclic or acyclic trivalent hydrocarbon group which may be substituted.)
Examples of the compound represented by the general formula (4) include U.S. Pat. No. 4,567,306 such as 4-ethyl-2,6,7-trioxa-1-phosphabicyclo- [2,2,2] -octane. Examples include compounds described in the publication.

(In the general formula (5), R ⁷ has the same meaning as R ⁴ in the general formula (2), but R ⁸ and R ⁹ each independently represents a hydrocarbon group which may be substituted; And b each represents an integer of 0 to 6, the sum of a and b is 2 to 6, and X represents an (a + b) -valent hydrocarbon group.
Among the compounds represented by the general formula (5), preferable examples include compounds represented by the following general formula (6).

(In the general formula (6), X is an alkylene, arylene and _{^{-Ar 1 - (CH 2) x}} -Qn- (CH 2) y-Ar 2 - represents a divalent group selected from the group consisting of, Ar ^{1, Ar 2, Q, x} , y, n are the general formula (3) ^Ar 1 ^{in, Ar 2, Q, x,} y, is synonymous with n ^{.R 16} and ^{R 17} are the above-mentioned general formula (5) in include compounds represented by R ⁸ and R ⁹ as synonymous), also containing the compounds described and JP 62-116587 Patent Publication No. Sho 62-116535.

(In the general formula ^{(7), X, Ar 1} , Ar 2, Q, x, y, n ^X in the general formula ^{(6), Ar 1, Ar} 2, Q, x, y, with n synonymous And R ¹⁸ has the same meaning as R ⁴ in formula (2).)

(In the general formula (8), R ¹⁹ and R ²⁰ each independently represent an aromatic hydrocarbon group, and at least one of the aromatic hydrocarbon groups is a carbon atom adjacent to the carbon atom to which the oxygen atom is bonded. Have a hydrocarbon group, m represents an integer of 2 to 4, each —OP (OR ¹⁹ ) (OR ²⁰ ) group may be different from each other, and X may be substituted. represents an m-valent hydrocarbon group.)
Among the compounds represented by the general formula (8), for example, compounds described in JP-A-5-78779 are preferable.

(In the general formula (9), R ^{21 to} R ²⁴ each independently represents a hydrocarbon group which may be substituted, and R ²¹ and R ²² , R ²³ and R ²⁴ are bonded to each other to form a ring. W may be formed, W represents a divalent aromatic hydrocarbon group which may have a substituent, and L represents a saturated or unsaturated divalent aliphatic which may have a substituent. Represents a hydrocarbon group.)
As the compound represented by the general formula (9), for example, those described in JP-A-8-259578 are used.

(In the general formula (10), R ^{25 to} R ²⁸ represent a monovalent hydrocarbon group which may be substituted, and R ²⁵ and R ²⁶ , R ²⁷ and R ²⁸ are bonded to each other to form a ring. And A and B each independently represent a divalent hydrocarbon group which may have a substituent, and n represents an integer of 0 or 1.)
Here, examples of the monovalent hydrocarbon group which may be substituted include an alkyl group, an aryl group, and a cycloalkyl group. The divalent hydrocarbon group which may have a substituent may be aromatic, aliphatic or alicyclic.

  The metal-phosphite ligand complex catalyst in the present invention may be formed in a reaction system for hydroformylation reaction, or may be prepared in advance. When preparing in advance, the metal compound which is a metal source constituting the catalyst is reacted in a solvent together with carbon monoxide, hydrogen and a phosphite ligand such as the above formulas (1) to (10) outside the reactor. . The solvent used for the catalyst preparation is usually selected from the hydroformylation reaction solvents described later, but is not necessarily the same solvent as the reaction solvent. The adjustment conditions are such that the reaction temperature is usually 40 ° C. or higher, preferably 50 ° C. or higher, more preferably 60 ° C. or higher, and usually 300 ° C. or lower, preferably 200 ° C. or lower, more preferably 150 ° C. or lower. The reaction pressure is usually 0.0001 MPaG or more, preferably 0.01 MPaG or more, more preferably 0.1 MPaG or more, and usually 20 MPaG or less, preferably 10 MPaG or less, more preferably 5 MPaG or less. The preparation time is usually 5 minutes or longer, preferably 10 minutes or longer, more preferably 30 minutes or longer, and is usually 15 hours or shorter, preferably 5 hours or shorter, more preferably 3 hours or shorter. If the preparation time is too short, the reaction may not proceed sufficiently and catalyst activity may not be obtained. On the other hand, if it is too long, the catalytic activity will decrease.

  The amount of the metal-phosphite ligand complex catalyst used in the hydroformylation reaction is such that the metal equivalent concentration in the hydroformylation reaction liquid is usually 1 ppm by weight or more, preferably 10 ppm by weight or more, and usually 10% by weight or less, preferably Is 1 wt% or less, more preferably 1000 wt ppm or less. If the metal concentration is too low, the reaction rate will be slow and the reaction will not proceed sufficiently.If the metal concentration is too high, the metal will also be extracted when purging high-boiling substances. .

  The ratio of the phosphite ligand to the metal is usually a molar ratio of ligand / metal = 0.1 to 10,000, preferably ligand / metal = 0.1 to 1000, more preferably 1 to 100. If the molar ratio is too low, the amount of coordination of the phosphite ligand to the metal decreases, so that the metal may not be sufficiently stabilized and may be deactivated. If it is too high, the concentration of the phosphite ligand in the reaction system will increase, and when purging high-boiling substances, the phosphite ligand will also be extracted and the phosphite ligand will be lost. Not right.

The temperature of the hydroformylation reaction is usually 20 ° C or higher, preferably 40 ° C or higher, more preferably 50 ° C or higher, and usually 300 ° C or lower, preferably 200 ° C or lower, more preferably 150 ° C or lower. If the reaction temperature is too low, the reaction rate will be slow and the reaction will not proceed sufficiently. If the reaction temperature is too high, the production of by-products will be promoted and the catalyst may be deactivated.
The pressure of the hydroformylation reaction is usually 0.0001 MPaG or more, preferably 0.01 MPaG or more, more preferably 0.2 MPaG or more, and usually 50 MPaG or less, preferably 30 MPaG or less, more preferably 20 MPaG or less. If the reaction pressure is too low, the reaction rate will be slow and the reaction will not proceed sufficiently. If the reaction pressure is too high, the design pressure of equipment such as a reactor will increase and the equipment burden will increase. The hydrogen partial pressure of the hydroformylation reaction is usually 0.0001 MPa or more, preferably 0.01 MPa or more, more preferably 0.1 MPa or more, and usually 20 MPa or less, preferably 10 MPa or less, more preferably 5 MPa or less. If the hydrogen partial pressure is too low, the reaction rate decreases, and if it is too high, the production of by-products increases. The carbon monoxide partial pressure is usually 0.0001 MPa or more, preferably 0.01 MPa or more, more preferably 0.1 MPa or more, and usually 20 MPa or less, preferably 10 MPa or less, more preferably 5 MPa or less. If the carbon monoxide partial pressure is too low, the reaction will not proceed. If it is too high, the partial pressure of the olefin will decrease and the reaction will not proceed. The ratio of hydrogen partial pressure / carbon monoxide partial pressure is usually 0.1 to 100, preferably 0.1 to 20, and more preferably 1 to 10. If this ratio is too small, the reaction will not proceed sufficiently, and if it is too high, the reaction will not proceed sufficiently or the production of by-products will increase.

The reaction time for performing the hydroformylation reaction is usually 1 minute or more, preferably 10 minutes or more, more preferably 20 minutes or more, and usually 24 hours or less, preferably 10 hours or less, more preferably 5 hours or less. is there. If the reaction time is too short, the reaction will not proceed sufficiently, and if it is too long, the formation of a high-boiling substance will proceed.
The hydroformylation reaction is usually performed in the presence of a solvent inert to the aldehyde produced by the reaction with the raw material olefin. Solvents that can be used in the hydroformylation reaction include aromatic hydrocarbons such as benzene, toluene, and xylene, aliphatic hydrocarbons such as hexane and octane, alicyclic hydrocarbons such as cyclohexane, alcohols such as butanol, octanol, and polyethylene glycol. And ethers such as triglyme and esters such as dioctyl phthalate. Moreover, the aldehyde produced | generated by reaction and aldehyde condensates, such as its trimer and a tetramer, can also be used. Furthermore, paraffins having the same carbon number as the raw material olefin can also be used. For example, in the case of hydroformylation of propylene, it is preferable to use a mixture with toluene, butyraldehyde or an aldehyde condensate such as trimer or tetramer.

  The kind of the reactor that can be used is not particularly limited, and a stirring tank type, a bubble column type, a plate column type, a tube type, a gas stripping type, or the like can be used. Usually, the raw material olefin, oxo gas and catalyst solution are continuously supplied to a continuous reactor and the reaction is carried out under the above hydroformylation reaction conditions. However, a batch reactor can also be used. Moreover, in order to keep the temperature of reaction constant, you may have an internal coil, a jacket, an external heat exchanger, etc.

The reaction product obtained by the hydroformylation reaction is continuously withdrawn from the reactor.
In the present invention, the reaction product liquid does not contain a catalyst and contains an aldehyde-containing liquid (A) containing an aldehyde and “aldehyde and / or a compound having a lighter boiling point than the aldehyde” and is lighter than the aldehyde and the aldehyde. It is separated into a catalyst solution (B) containing a total of 20% by weight or more of a boiling point compound (hereinafter, abbreviated to aldehyde and a compound having a lighter boiling point than the aldehyde and abbreviated as a light boiling point compound) and containing a catalyst. The The separation method is not particularly limited, and examples thereof include distillation, evaporation, gas stripping, gas absorption, and extraction. Among these, distillation is preferable. In the case of distillation, the aldehyde-containing liquid (A) is usually obtained by cooling the distillate from the top of the distillation tower, and the catalyst liquid (B) is recovered from the tower bottom.

The aldehyde-containing liquid (A) usually contains the produced aldehyde as a main component, contains a compound having a light boiling point, and does not contain a catalyst.
The catalyst liquid (B) usually contains the produced aldehyde and / or a compound having a lighter boiling point than the aldehyde, a catalyst, and a compound having a high boiling point which is usually a reaction by-product. In the present invention, the catalyst liquid (B ), The total concentration of light-boiling compounds is 20% by weight or more, preferably 25% by weight or more, more preferably 30% by weight or more, and usually 95% by weight or less, preferably 90% by weight or less, more Preferably it is 85 weight% or less, Most preferably, it is 75 weight% or less. Since light-boiling compounds have higher solubility of phosphite ligands than high-boiling compounds, phosphite ligands precipitate if the total concentration of light-boiling compounds is too low. On the other hand, if the total concentration of light-boiling compounds is too large, the catalyst liquid (B) is circulated in the hydroformylation reaction, so that there is a risk that the light-boiling compounds will become high-boiling substances during the reaction.

  In the present invention, the separation of the reaction product liquid is set to 5: 1 to 1: 5 in a weight ratio of the aldehyde-containing liquid (A): the catalyst liquid (B). Preferably, the weight ratio is 4.5: 1 or more, more preferably 4: 1 or more, while preferably 1: 4.5 or less, more preferably 1: 4 or less. When the ratio of the catalyst solution (B) is reduced, the phosphite ligand is concentrated in the catalyst solution and deposited. On the other hand, when the ratio of the catalyst solution (B) is increased, the amount of the circulating catalyst is increased, resulting in a problem that the apparatus is increased in size.

  If the total concentration of light-boiling compounds in the catalyst liquid (B) and the ratio of the aldehyde-containing liquid (A): catalyst liquid (B) are changed using, for example, a distillation tower, the aldehyde content at the top of the tower Since the liquid is mainly composed of aldehyde, once the feed composition is determined, they cannot be changed independently. In such a case, if a part of the catalyst liquid is purged during the circulation of the catalyst liquid to the reactor, the light boiling point substance concentration can be changed. Therefore, the above two parameters can be changed independently. it can.

  In the present invention, at least a part of the catalyst liquid (B) is circulated in the hydroformylation reaction step, but the circulated catalyst liquid (B) is maintained at 40 ° C. or higher, preferably 45 ° C. or higher, more preferably 50 ° C. Maintained above. The upper limit of the temperature of the catalyst liquid (B) is not particularly limited, but it is usually lower than the bottom temperature of the distillation column, preferably 200 ° C. or lower, preferably because the reaction product is preferably separated by distillation. It is 150 degrees C or less, More preferably, it is about 120 degrees C or less. Since the solubility of the phosphite ligand in the catalyst liquid (B) increases as the temperature increases, the phosphite ligand precipitates in the catalyst liquid (B) when the temperature decreases. On the other hand, when the temperature is too high, deactivation of the catalyst and formation of a high-boiling point substance proceed.

  “Maintaining at 40 ° C. or higher” means that the temperature is 40 ° C. or higher at any stage after separation from the reaction product solution until it is circulated to the hydroformylation reaction step. The term “until” refers to the time until the catalyst liquid (B) is directly supplied to the hydroformylation reactor, or until the catalyst solution (B) is mixed with the reaction solvent or other raw materials. In order to satisfy the above-described separation conditions of the reaction product liquid in the present invention, it is preferable to separate the aldehyde-containing liquid (A) and the catalyst liquid (B) by distillation. The column bottom temperature is usually 40 to 200 ° C, preferably 50 to 150 ° C. In order to lower the column bottom temperature, it is necessary to operate the distillation column at a high vacuum, which is not economical. When the column bottom temperature is raised, the catalyst is deactivated and the material has a high boiling point. The tower top pressure may be performed under conditions such that the tower bottom temperature is within the above range, but is usually 50 mmHg or more, preferably 100 mmHg or more, and usually atmospheric pressure or less. The reflux ratio is 0.1 to 10, preferably 0.5 to 5.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded.
(Example 1)
A hydroformylation reaction was carried out in which propylene was continuously supplied to a fully mixed tank reactor to produce butyraldehyde. Propylene is supplied at 7.1 kg / Hr as a raw material to a complete mixing tank reactor with an inner diameter of 400 mm and a height of 1500 mm, and a stirring blade. Butyraldehyde, rhodium acetate and ligand A described below are used as catalyst solutions in advance. The liquid containing the complex catalyst obtained by the adjustment and the circulating catalyst liquid (B) were combined and supplied at 36.7 kg / Hr. Cooling water was passed through the reactor jacket to adjust the reaction temperature to 70 ° C. H ₂ / CO = 1 synthesis gas was fed to the reactor so that the pressure was 0.98 MpaG. The rhodium concentration in the reaction solution was 162 ppm by weight, the ligand / Rh molar ratio was 4, and the free ligand concentration was 0.44% by weight. Ligand A shown below was used as the ligand. The stirring power of the reactor was 2 kW / m ³ , the H ₂ partial pressure was 0.42 MPa, and the CO partial pressure was 0.14 MPa. The reaction product liquid was extracted so that the liquid level of the reactor became constant, and the reaction product liquid thus extracted and the synthesis gas supplied to the reactor were brought into countercurrent contact to recover unreacted propylene. The reaction product liquid from which propylene was removed was supplied to a distillation column (inner diameter: 151 mm, height: 8600 mm), and separated such that aldehyde-containing liquid (A): catalyst liquid (B) = 1: 3.2. The bottom temperature of the distillation column was 72 ° C., the top pressure was 0.067 MPa, and the reflux ratio was 1. The distillation column was packed with irregular packing to a packing length of 7500 mm. The distilled aldehyde-containing liquid (A) was 11.6 kg / Hr. A portion of the catalyst solution was purged from the removed catalyst solution (B) at 47 g / Hr, and the remainder was circulated to the reactor. The temperature of the catalyst solution (B) taken out was 72 ° C., the temperature when being supplied to the reactor was 72 ° C., and the catalyst solution (B) was maintained at 50 ° C. or higher. The concentration of butyraldehyde and the compound having a lighter boiling point in the catalyst liquid (B) was 50.6% by weight in total. At this time, precipitation of the ligand was not confirmed in the catalyst solution.

Example 2
The catalyst solution (B) obtained in the same manner as in Example 1 and the aldehyde-containing solution (A) were prepared from the following concentration of “aldehyde and lighter boiling point compound” contained in the catalyst solution (B). The mixture was mixed so as to have the concentration described in 1. and charged into an evaporator. The amount of the charged solution at this time was 400 g, and the concentration of the free ligand contained therein and the concentration of “aldehyde and a compound having a lighter boiling point than this” were 0.45 wt% and 82.5 wt%, respectively. It was. By heating the evaporator and distilling 300 [g] of the aldehyde-containing liquid (A), the concentration of “aldehyde and a compound having a lighter boiling point than that contained in 100 g of the residual liquid (catalyst liquid (B)) is 30 wt. %, And the free ligand concentration was adjusted to 1.80% by weight. Thereafter, when the temperature of the remaining liquid of the evaporator was set to 50 ° C. and it was confirmed whether a precipitate was present in the remaining liquid, no precipitation of the ligand occurred.

Example 3
In Example 2, the concentration of “aldehyde and a compound having a lighter boiling point than that in the charged solution”, the amount of the aldehyde-containing liquid (A) distilled, the amount of the remaining solution, and the free ligand concentration in the remaining solution Was carried out in the same manner except that was changed to the values shown in Table 1. The results are shown in Table 2.

Comparative Example 1
In Example 2, it carried out similarly except having changed the temperature of the residual liquid into the value shown in Table 1. The results are shown in Table 2.

Comparative Example 2
In Example 2, except that the concentration of “aldehyde and a compound having a lighter boiling point than that” in the charged solution and the concentration of “aldehyde and a compound having a lighter boiling point than this” in the remaining solution were changed to the values shown in Table 1. Was carried out in the same manner. The results are shown in Table 2.

Comparative Example 3
In Example 2, the concentration of “aldehyde and a compound having a lighter boiling point than that in the charged solution”, the amount of the aldehyde-containing solution (A) distilled, the amount of the remaining solution, and the concentration of the free ligand in the remaining solution It implemented similarly except having changed into the value shown in Table 1. The results are shown in Table 2.

Comparative Example 4
In Example 3, the concentration of “aldehyde and lighter boiling point compound” in the charged solution, the amount of the aldehyde-containing solution (A) distilled, the amount of the remaining solution, the concentration of free ligand in the remaining solution, and It implemented similarly except having changed the temperature of the residual liquid into the value shown in Table 1. The results are shown in Table 2.

Claims (2)

  In a method for producing a corresponding aldehyde by hydroformylating an olefinic unsaturated compound in the presence of a metal-phosphite ligand complex catalyst, the reaction product obtained by the hydroformylation reaction is not contained in a catalyst. And an aldehyde-containing liquid (A) containing an aldehyde, an aldehyde and / or a compound having a lighter boiling point than the aldehyde, and the total content of the aldehyde and the compound having a lighter boiling point than the aldehyde is 20% by weight or more, and The catalyst solution (B) containing the catalyst is separated at a ratio of aldehyde-containing solution (A): catalyst solution (B) = 5: 1 to 1: 5 (weight ratio), and the catalyst solution (B) is separated. A method for producing an aldehyde, comprising maintaining at 40 ° C. or higher and circulating in a hydroformylation reaction step.   The process according to claim 1, wherein the reaction product liquid is separated by distillation.