JP2006131573A - Process for producing aldehyde - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydroformylation process having high recovery ratio of a noble metal. <P>SOLUTION: The subject process for producing an aldehyde comprises subjecting an olefin to a hydroformylating reaction with hydrogen and carbon monoxide in the presence of a group 8 metal-organophosphorus complex catalyst. The process is characterized as including a step of taking out a part of a hydroformylating reaction liquid, mixing the taken out reaction liquid with a poor solvent for the group 8 metal-organophosphorus complex catalyst, hydrogen and an organic acid, crystallizing the group 8 metal-organophosphorus complex catalyst and then separating the crystallized substance from the reaction liquid. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing an aldehyde, and more particularly to a method for producing an aldehyde by reacting an olefin with hydrogen and carbon monoxide to form an aldehyde in the presence of a Group 8 metal-organic phosphorus complex catalyst. .

  Hydroformylates olefinically unsaturated organic compounds with carbon monoxide and hydrogen (usually called syngas or oxogas) in the presence of rhodium (Group 8 metal) -phosphorus (ligand) complex catalyst and free phosphorus ligand Processes for the production of aldehydes are known in the art as seen, for example, in the basic low pressure oxohydroformylation process of US Pat. No. 3,527,809 and the rhodium catalyzed hydroformylation process of US Pat. No. 4,148,830. well known.

  Since the hydroformylation reaction uses an expensive noble metal catalyst, it is ideal to use the catalyst semipermanently. Therefore, the product and the catalyst are separated by stripping or distillation, and the separated catalyst is used for the next reaction (or the reaction is performed while separating the product). However, in such a hydroformylation reaction, various high-boiling by-products are generated and accumulated, so it is necessary to continuously or intermittently extract a part of the catalyst solution from the reaction system. Since the extracted catalyst solution contains an expensive noble metal, it is important to recover it efficiently.

For example, in Japanese Examined Patent Publication No. 59-23858, in the presence of alcohol and water, it is brought into contact with hydrogen at a treatment temperature of 95 ° C. or less, and a rhodium-triarylphosphine complex coordinated with a hydrogen atom is crystallized and recovered. A method is described.
However, with the conventional methods, the recovery rate of noble metals (group 8 metals) has not been sufficient.
US Pat. No. 3,527,809 U.S. Pat. No. 4,148,830 Japanese Patent Publication No.59-23858

  An object of the present invention is to provide a hydroformylation process with a higher recovery rate of noble metals (group 8 metals).

In this regard, as a result of intensive studies by the present inventors, it was surprising that when the hydrogen treatment was performed in the presence of a poor solvent and the rhodium complex was crystallized, the recovery of the rhodium complex was caused when an organic acid was present in the system. It has been found that the rate is improved and the present invention has been completed. That is, the gist of the present invention resides in the following (1) to (5).
(1) In a method for producing an aldehyde by hydroformylating an olefin with hydrogen and carbon monoxide in the presence of a Group 8 metal-organophosphorus complex catalyst, a part of the hydroformylation reaction solution is extracted, Including a step of mixing a poor solvent, hydrogen, and an organic acid for the Group metal-organophosphorus complex catalyst to crystallize the Group 8 metal-organophosphorus complex catalyst, and then separating the crystallized product from the reaction solution. Feature method.
(2) The method according to (1) above, wherein the mixed amount of the organic acid is 0.0001 to 10 parts by weight with respect to 100 parts by weight of the poor solvent.
(3) The method according to (1) or (2) above, wherein the separated crystallization product is circulated in the hydroformylation reaction step.
(4) The method according to any one of (1) to (3) above, wherein the Group 8 metal is rhodium.
(5) The method according to any one of (1) to (4) above, wherein an aromatic hydrocarbon is mixed together with a poor solvent, hydrogen, and an organic acid.

  According to the present invention, it is possible to provide a hydroformylation process with a higher recovery rate of noble metals (group 8 metals).

The present invention will be described in detail below.
The present invention relates to a method for producing an aldehyde by hydroformylating an olefin with hydrogen and carbon monoxide in the presence of a Group 8 metal-organophosphorus complex catalyst, extracting a part of the hydroformylation reaction solution, Including a step of mixing a poor solvent for the Group 8 metal-organic phosphorus complex catalyst, hydrogen, and an organic acid to crystallize the Group 8 metal-organic phosphorus complex catalyst, and then separating the crystallized product from the reaction solution. It is characterized by.

In the method of the present invention, the group 8 metal is a group metal in the periodic table of 1983, and is a group 8-10 metal in the current periodic table, specifically, rhodium, palladium, cobalt, Examples include ruthenium and platinum, and rhodium is preferred.
In carrying out the method of the present invention, Group 8 metal compounds used as catalyst raw materials include, for example, rhodium chloride, palladium chloride, ruthenium chloride, platinum chloride, rhodium bromide, rhodium iodide, rhodium sulfate, rhodium nitrate, nitric acid. Water-soluble inorganic salts or inorganic complex compounds such as palladium, ammonium rhodium chloride, sodium rhodium chloride, water-soluble organic acid salts such as rhodium formate, rhodium acetate, palladium acetate, rhodium propionate, palladium propionate, rhodium octanoate, etc. Can be mentioned. Moreover, you may use the complex kind of each metal. Of these, rhodium acetate is preferably used from the viewpoint of reaction activity and catalyst cost.

  Moreover, as an organophosphorus compound used for hydroformylation reaction, the phosphine or phosphite etc. which have the capability as a monodentate ligand or a polydentate ligand are mentioned. Examples of phosphine include phosphine having an alkyl substituent on a phenyl group such as tris (p-tolyl) phosphine, trixylylphosphine, tris (p-ethylphenyl) phosphine, and alkoxy on a phenyl group such as tris (p-methoxyphenyl) phosphine. Examples include a phosphine having a substituent, and a triarylphosphine having a substituent that is inactive under hydroformylation reaction conditions on the phenyl group. Among them, it is preferable to use triphenylphosphine because of its availability.

Monodentate phosphites include trialkyl phosphites such as trimethyl phosphite and tricyclohexyl phosphite, triphenyl phosphites optionally having substituents, and trinaphthyl phosphites optionally having substituents. Such as triaryl phosphites and alkylaryl phosphites.
As examples of multidentate phosphites, for example, trivalent phosphite compounds represented by the following formulas (1) to (10) can be used.

(In the formula, R ^{1 to} R ³ each independently represents an optionally substituted monovalent hydrocarbon group.)

In the formula (1), examples of the optionally substituted monovalent hydrocarbon group 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- Trialkyl phosphites such as n-octyl phosphite and tri-n-dodecyl phosphite; triaryl phosphites such as triphenyl phosphite and trinaphthyl phosphite; dimethylphenyl phosphite, diethylphenyl phosphite, ethyl diphenyl phosphite And alkyl aryl phosphites. Further, for example, bis (3,6,8-tri-t-butyl-2-naphthyl) phenyl phosphite, bis (3,6,8-tri-t-) described in JP-A-6-122642. Butyl-2-naphthyl) (4-biphenyl) phosphite or the like may be used. Most preferred among these is triphenyl phosphite.

(In the formula, R ⁴ represents a divalent hydrocarbon group which may be substituted, and R ⁵ represents a monovalent hydrocarbon group which may be substituted.)

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

  Specific examples of the compound represented by the formula (2) include neopentyl (2,4,6-tert-butyl-phenyl) phosphite and ethylene (2,4,6-tert-butyl-phenyl) phosphite. And the like described in US Pat. No. 3,415,906.

(Wherein R ¹⁰ has the same meaning as R ⁵ in formula (2), Ar ¹ and Ar ² each independently represent an optionally substituted arylene group, and x and y are each independently 0 or 1 and Q is a bridging group selected from the group consisting of —CR ¹¹ R ¹² —, —O—, —S—, —NR ¹³ —, —SiR ¹⁴ R ¹⁵ and —CO—, R ¹¹ and R ¹² each independently represent 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 each independently represent a hydrogen atom or Represents a methyl group, and n represents 0 or 1.)

  Specific examples of the compound represented by the formula (3) include 1,1′-biphenyl-2,2′-diyl- (2,6-di-t-butyl-4-methylphenyl) phosphite, etc. US Pat. No. 4,599,206, 3,3′-di-t-butyl-5,5′-dimethoxy-1,1′-biphenyl-2,2′-diyl- (2-t Examples include compounds described in US Pat. No. 4,717,775 such as -butyl-4-methoxyphenyl) phosphite.

(In the formula, R ⁶ represents a cyclic or acyclic trivalent hydrocarbon group which may be substituted.)

  Specific examples of the compound represented by the formula (4) include, for example, U.S. Pat. No. 4,567,306 such as 4-ethyl-2,6,7-trioxa-1-phosphabicyclo- [2,2,2] -octane. And the compounds described in Japanese Patent Publication.

(Wherein R ⁷ has the same meaning as R ⁴ in formula (2), R ⁸ and R ⁹ each independently represents a hydrocarbon group which may be substituted, and a and b each represent 0 to 6; Represents an integer, the sum of a and b is 2 to 6, and X represents an (a + b) -valent hydrocarbon group.

  Preferred examples of the compound represented by the formula (5) include, for example, 6,6 ′-[[3,3 ′, 5,5′-tetrakis (1,1′-dimethylethyl)-[1,1 '-Biphenyl] -2,2'-diyl] bis (oxy)] bis-benzo [d, f] [1,3,2] dioxaphosphine and the like described in JP-A-2-231497 And the like.

(Wherein, X is an alkylene, arylene and _{^{-Ar 1 - (CH 2) x}} -Qn- (CH 2) y-Ar 2 - a divalent radical selected from the group consisting ^{of, R 16} and ^{R 17} Each independently represents an optionally substituted hydrocarbon group, Ar ¹ , Ar ² , Q, x, y, and n are as defined in Formula (3).

  Specific examples of the compound represented by the formula (6) include, for example, compounds described in JP-A-62-116535 and JP-A-62-116587.

(In the formula, X, Ar ¹ , Ar ² , Q, x, y, n are synonymous with formula (6), and R ¹⁸ is synonymous with R ⁴ in formula (2).)

(Wherein R ¹⁹ and R ²⁰ each independently represents an aromatic hydrocarbon group, and at least one of the aromatic hydrocarbon groups has a hydrocarbon group adjacent to the carbon atom to which the oxygen atom is bonded). M represents an integer of 2 to 4, each —O—P (OR ¹⁹ ) (OR ²⁰ ) group may be different from each other, and X is an optionally substituted m-valent hydrocarbon. Group.)

  Among the compounds represented by the formula (8), for example, compounds described in JP-A-5-178777, 2,2′-bis (di-1-naphthyl phosphite) -3,3 ′, Compounds described in JP-A No. 10-45776 such as 5,5′-tetra-t-butyl-6,6′-dimethyl-1,1′-biphenyl are preferred.

(In the formula, R ^{21 to} R ²⁴ represent a hydrocarbon group which may be substituted, and even if they are independent of each other, R ²¹ and R ²² , R ²³ and R ²⁴ are bonded to each other. A ring may be formed, W represents a divalent aromatic hydrocarbon group which may have a substituent, and L represents a saturated or unsaturated divalent which may have a substituent. Indicates an aliphatic hydrocarbon group.)

  As the compound represented by the formula (9), for example, those described in JP-A-8-259578 are used.

(In the formula, 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 may be bonded to each other to form a ring. , A and B each independently represent a divalent aromatic hydrocarbon group which may have a substituent, and n represents an integer of 0 or 1.

  In introducing the organophosphorus compound into the reactor, the organophosphorus compound can be introduced into the reaction system as it is, but it is preferable to introduce it by dissolving it in an organic solvent in view of ease of handling. .

Examples of the olefin used in the present invention include olefins having 2 to 20 carbon atoms, such as α-olefins such as ethylene, propylene, butene, pentene, hexene, and octene, or internal olefins having double bonds other than α-position. Etc.
In the present invention, hydroformylation reaction of an olefin having n carbon atoms (n is an integer of 2 to 20) is carried out using a Group 8 metal-organophosphorus complex catalyst, and n + 1 (n is carbon of olefin as a raw material) Aldehyde) is produced.

  Examples of the aldehyde having a carbon number of n + 1 (n is the same as the carbon number n of the olefin as a raw material) include propionaldehyde, butyraldehyde, pentylaldehyde, hexylaldehyde, heptylaldehyde, octylaldehyde, nonylaldehyde, decylaldehyde and the like. These aldehydes are usually produced in the form of a mixture of a straight chain and a branched chain.

In the hydroformylation reaction, an olefin is reacted with hydrogen and carbon monoxide in the presence of a Group 8 metal-organophosphorus complex catalyst.
As the solvent for the hydroformylation reaction, a solvent having a boiling point higher than that of the aldehyde to be generated and having no reaction inhibiting action is preferable. For example, aromatic hydrocarbons such as benzene, toluene and xylene, aliphatic hydrocarbons such as hexane and octane, and butyl acetate. And esters such as butyl butyrate or ketones.

  As reaction conditions for the hydroformylation reaction using a rhodium complex catalyst, the hydrogen partial pressure is usually 0.01 to 20 MPa, the carbon monoxide partial pressure is 0.01 to 20 MPa, the total pressure is 0.1 to 30 MPa, and the hydrogen partial pressure / one. Carbon oxide partial pressure = 0.1-10, reaction temperature 60-200 ° C., Rh concentration is several ppm to several weight%, P (free organophosphorus ligand) / Rh = 2-10000 (molar ratio), reaction It is appropriately selected within the range of several minutes to several tens hours.

The olefin hydroformylation reaction is carried out under the above hydroformylation reaction conditions by continuously supplying the raw material olefin and oxo gas to a normal flow reactor, but a batch reactor can also be used. .
The main flow reaction methods are a stripping method and a liquid circulation method. Referring to FIGS. 1 and 2, the stripping method holds the catalyst solution 4 in the reactor 3, continuously supplies the olefin 2 and the oxo gas 1, and vaporizes the aldehyde generated by the reaction in the reactor. And taking it out of the system. On the other hand, in the liquid circulation system, not only the olefin 2 and oxo gas 1 but also the catalyst liquid is continuously supplied to the reactor 3, and the aldehyde generated in the reactor is extracted out of the reactor by the liquid phase 7 together with the catalyst liquid. It is. The product in the mixture withdrawn from the reactor is separated into the produced aldehyde 5 and the catalyst solution 4 by a separation operation 8 such as stripping with unreacted gas or distillation. The separated product aldehyde is withdrawn out of the system, while the catalyst solution is recycled to the reactor.

  For example, in the case of a liquid circulation system, aldehyde produced by the hydroformylation reaction is recovered by being separated from the catalyst liquid by stripping with unreacted gas or distillation, etc., but a part of the reaction liquid has a high boiling point. To avoid product accumulation, it is withdrawn out of the reaction system continuously or intermittently. An amount of catalyst and an organophosphorus compound corresponding to the extracted amount are newly supplied to the reaction system. On the other hand, in the case of the stripping method, the catalyst liquid retained in the reactor is usually withdrawn out of the reaction system intermittently in many cases.

The method of the present invention is applied to the reaction solution extracted from the reaction system. Specifically, the extracted reaction liquid is mixed with a poor solvent, hydrogen, and an organic acid to crystallize the Group 8 metal-organic phosphorus complex catalyst, and then the crystallized product is separated from the reaction liquid.
The order of mixing the poor solvent, hydrogen, and organic acid into the reaction solution may be any order. For example, the organic acid may be added to the poor solvent, and then the reaction solution and finally hydrogen may be mixed in this order. Considering the actual industrialization, for example, there is a method in which a poor solvent containing an organic acid and a reaction solution are simultaneously added to a hydrogen-pressurized tank and mixed.
In the present invention, from the viewpoint of further improving the recovery rate, when mixing the poor solvent, hydrogen, and the organic acid, it is preferable to add the aromatic hydrocarbon in the coexistence.

  The poor solvent in the present invention is based on the premise that the solubility of the Group 8 metal compound is lower than that of the reaction solution. However, in the crystallization operation of the present invention, it maintains a homogeneous phase with the reaction solution, and the reaction What does not participate in the reaction in the system is good. Specifically, methanol, ethanol, propanol, butanol, acetone and a mixture thereof with water are mentioned, and from the viewpoint of the recovery rate of Group 8 metal, preferably a mixture of water and an alcohol having 1 to 3 carbon atoms, The mixing ratio is about 5: 1 to 1: 5, preferably 1: 1 to 1: 4. Usually, if the ratio of water is small, the recovery rate is lowered due to the solubility of the complex. Conversely, even if the ratio of water is too high, the system becomes two phases of oil water, and a good recovery rate cannot be obtained.

The ratio of the poor solvent to the reaction solution is usually about 10: 1 to 1: 2, preferably 5: 1 to 1: 1. Usually, it is preferable that the amount of poor solvent is small because the process scale is small, but basically, an amount that can provide an appropriate recovery rate is selected. The composition of the poor solvent also affects.
Examples of the organic acid in the present invention include formic acid, acetic acid, propionic acid, butyric acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid and the like, and the recovery rate of Group 8 metals In view of the above, an acid having 8 or less carbon atoms is preferable, and an acid having 4 or less carbon atoms is particularly preferable.

The amount of the organic acid is usually 0.0001% by weight or more, preferably 0.001% by weight or more, and usually 10% by weight or less, preferably 5% by weight or less based on the poor solvent. A large amount of the organic acid may be added, but if it is too much, it is not economical, and if it is too little, the effect of improving the Group 8 metal recovery rate cannot be obtained.
In addition, examples of the aromatic hydrocarbon in the present invention include benzene, toluene, xylene, ethylbenzene, butylbenzene, decylbenzene, dodecylbenzene, and the like. From the viewpoint of the recovery rate of Group 8 metals, toluene, Xylene and ethylbenzene are mentioned, and particularly preferred is toluene.

The amount of the aromatic hydrocarbon is usually 0.01% by weight or more, preferably 0.1% by weight or more, and usually 20% by weight or less, preferably 10% by weight or less based on the poor solvent. If the amount of aromatic hydrocarbon is too small, the effect of improving the Group 8 metal recovery rate cannot be obtained, and if it is too much, the Group 8 metal recovery rate is lowered.
The reaction liquid, poor solvent, and hydrogen may be mixed at any temperature. Usually, the reaction liquid is normal temperature to 200 ° C, hydrogen is normal temperature to 100 ° C, and the poor solvent is minus 20 ° C to 100 ° C. Supplied at a range of temperatures.

The temperature during the crystallization operation is usually in the range of minus 20 ° C to 50 ° C. Moreover, the pressure in the case of crystallization operation is normally performed in the range of a normal pressure-10MPa.
The crystallized Group 8 metal compound is separated from the liquid by a commonly used solid-liquid separation method. Specifically, there are methods such as decantation, centrifugation, and filtration, and industrially, centrifugal filtration is often used.

  The obtained Group 8 metal compound is returned to the reactor. In that case, it is usually dissolved in the reaction solvent and returned to the reactor.

EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to a following example, unless the paper is exceeded.
Example 1
From the catalyst solution extracted from the hydroformylation reaction of propylene using rhodium acetate as the Group 8 metal compound and triphenylphosphine as the organophosphorus ligand, the reaction solvent was removed by distillation to obtain a kettle residue having the following composition. .

Rhodium complex concentration (converted to rhodium atom) 636wtppm
Triphenylphosphine 40.6wt%
Triphenylphosphine oxide 2.4wt%
High boiling point by-product 56.9 wt%
The above-mentioned “bottle residual liquid 24 g” and “isopropyl alcohol: water: formic acid = 69.9986: 30: 0.0014 (weight ratio) mixed solvent 64 g” have a volume of 0.2 L in an inert gas atmosphere. After placing in an electromagnetic induction stirring type autoclave and sealing the autoclave, hydrogen gas is injected at a temperature of 15 ° C. to a pressure of 2 Mpa while gently stirring, and hydrogen treatment is performed for 4 hours while maintaining this pressure and temperature. went. Thereafter, hydrogen gas was purged, and solid-liquid separation was performed by ordinary vacuum filtration. When the amount of the separated rhodium complex was quantified, when the amount of the rhodium complex was quantified, the recovery rate of the rhodium complex was 37.3% in terms of rhodium atoms.

Example 2
The same operation as in Example 1 was performed except that 64 g of a mixed solvent of isopropyl alcohol: water: normal butyric acid = 69.98: 30: 30: 0.012 (weight ratio) was used as the mixed solvent. As a result, the recovery rate of the rhodium complex was 41.1%.

Example 3
Example 1 except that 64 g of a mixed solvent of isopropyl alcohol: water: formic acid: normal butyric acid: isobutyric acid = 69.9086: 30: 0.0014: 0.0675: 0.0225 (weight ratio) was used as the mixed solvent. The same operation was performed. As a result, the recovery rate of the rhodium complex was 58.6%.

Example 4
As a mixed solvent, 64 g of a mixed solvent of isopropyl alcohol: water: formic acid: normal butyric acid: isobutyric acid: toluene = 68.5086: 30: 0.0014: 0.0675: 0.0225: 1.4 (weight ratio) was used. Except for this, the same operation as in Example 1 was performed. As a result, the recovery rate of the rhodium complex was 79.2%.

Comparative Example 1
The same operation as in Example 1 was performed, except that 64 g of a mixed solvent of isopropyl alcohol: water = 70: 30 (weight ratio) (containing no organic acid) was used as the mixed solvent. As a result, the recovery rate of the rhodium complex was 15.7%.

It is a figure of the reactor of a stripping system. It is a figure of the reactor of a liquid circulation system.

Explanation of symbols

1 Oxo gas 2 Olefin 3 Reactor 4 Catalyst liquid 5 Generated aldehyde 6 Purge gas 7 Reaction liquid (aldehyde + catalyst liquid)
8 Separator

Claims (5)

  In the method of producing an aldehyde by hydroformylating olefin with hydrogen and carbon monoxide in the presence of a Group 8 metal-organophosphorus complex catalyst, a part of the hydroformylation reaction solution is extracted, and Group 8 metal- It comprises a step of mixing a poor solvent for the organophosphorus complex catalyst, hydrogen and an organic acid to crystallize the Group 8 metal-organophosphorus complex catalyst, and then separating the crystallized product from the reaction solution. Method.   The method according to claim 1, wherein the mixed amount of the organic acid is 0.0001 to 10 parts by weight with respect to 100 parts by weight of the poor solvent.   The method according to claim 1 or 2, wherein the separated crystallization product is recycled to the hydroformylation reaction step.   The method according to any one of claims 1 to 3, wherein the Group 8 metal is rhodium.   The method according to claim 1, wherein an aromatic hydrocarbon is mixed together with a poor solvent, hydrogen, and an organic acid.