JP2001206865A - Method for stopping operation of hydroformylation reactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for stopping the operation of a hydroformylation reactor without deteriorating a rhodium complex catalyst. SOLUTION: This method for stopping the operation of a continuous hydroformylation reactor, comprising continuously supplying an olefin and an oxo gas into a reaction medium containing a rhodium complex catalyst to produce an aldehyde, characterized by starting the lowering of temperature in a state that the olefin is left in the reaction medium, in a process for stopping the supply of the olefin and lowering the temperature of the reaction medium containing the rhodium complex catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for shutting down a hydroformylation reactor using a rhodium complex catalyst. In particular, the present invention relates to an operation stop method for suppressing deterioration of a rhodium complex catalyst.

[0002]

2. Description of the Related Art Conventionally, as a method for stopping the operation of a hydroformylation reactor, even after the supply of olefin is stopped, the reaction temperature is maintained and the reaction is carried out by pushing out all the remaining olefin in the reactor and then lowering the temperature. A method of stopping the operation of the vessel has been implemented. After the reactor is stopped, the reaction medium in which the rhodium complex catalyst is dissolved (hereinafter, this may be referred to as "reaction liquid") is reused when the reactor is started again. However, the conventional method of stopping the operation of the reactor has a disadvantage that the activity of the rhodium complex catalyst decreases when the operation of the reactor is restarted. Further, there is no description of a method of shutting down the hydroformylation reactor effective for suppressing the deterioration of the rhodium complex catalyst as in the method of the present invention.

[0003]

The problem to be solved by the present invention is as follows.
An object of the present invention is to provide a method for shutting down a reactor without deteriorating a rhodium complex catalyst.

[0004]

Means for Solving the Problems As a result of diligent studies on the above-mentioned problems, the present inventors have found that when the operation of the hydroformylation reactor is stopped, the temperature is lowered in the presence of the olefin, thereby suppressing the deterioration of the rhodium complex catalyst. They have found that they can do this and have completed the present invention. That is, the gist of the present invention is to provide a reaction medium containing a rhodium complex catalyst,
A method for shutting down a continuous hydroformylation reactor for continuously supplying an olefin and an oxo gas to produce an aldehyde, wherein the supply of the olefin is stopped and the temperature of the reaction medium containing the rhodium complex catalyst is lowered. The method for shutting down the operation is characterized in that the temperature is started while the olefin remains in the reaction medium.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The present invention is not limited to a linear or branched chain,
It can be applied to olefin or internal olefin hydroformylation reactions. Preferably, propylene, butene-1, hexene-1, octene-1, dodecene-
1, applied to hydroformylation reaction of α-olefin such as tetradecene-1, especially propylene. The ligand of the rhodium complex catalyst is not particularly limited, but for example, a trivalent organic phosphorus compound is suitably used. The trivalent organophosphorus compound may be any conventional trivalent organophosphorus compound having the ability to function as a monodentate ligand or a polydentate ligand. Specifically, for example, compounds represented by the following general formulas (1) to (11) And the compounds represented.

[0006]

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(Wherein, R ^{1 to} R ³ each independently represent a monovalent hydrocarbon group which may be substituted.) The monovalent hydrocarbon group which may be substituted includes alkyl Group, aryl group, cycloalkyl group and the like. Specific examples of the compound represented by the formula (1) include, for example, trialkylphosphines such as tributylphosphine and trioctylphosphine; triphenylphosphine;
Triaryl phosphines such as tolyl phosphine; tricycloalkyl phosphines such as tricyclohexyl phosphine; alkyl aryl phosphines such as butyl diphenyl phosphine and dipropyl phenyl phosphine; cycloalkyl aryl phosphines such as cyclohexyl diphenyl phosphine. Preferred among these is triphenylphosphine.

[0008]

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(Wherein, R ^{1 to} R ³ have the same meanings as in formula (1).) Specific examples of the compound represented by formula (2) 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; dimethyl phenyl phosphite, diethyl phenyl phosphite, ethyl diphenyl phosphite and the like And the like. Further, for example, bis (3,6,8-tri-t-butyl-2-naphthyl) phenyl phosphite and bis (3,6,8-tri-t-butyl-) described in JP-A-6-122624. For example, 2-naphthyl) (4-biphenyl) phosphite may be used. The most preferred of these is triphenyl phosphite.

[0010]

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(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.) As the divalent hydrocarbon group, an alkylene group which may contain oxygen, nitrogen, sulfur atom, etc. in the middle of the carbon chain; a cycloalkylene which may contain oxygen, nitrogen, sulfur atom, etc. in the middle of the carbon chain A divalent aromatic group such as phenylene or naphthylene; a divalent aromatic group in which a divalent aromatic ring is directly or intermediately bonded via an atom such as an alkylene group, oxygen, nitrogen, or sulfur; Examples thereof include those in which a valent aromatic group and an alkylene group are bonded directly or in the middle via an atom such as oxygen, nitrogen, or sulfur. 1
Examples of the valent hydrocarbon group include an alkyl group, an aryl group, and a cycloalkyl group.

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

[0013]

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(Wherein R^TenIs R in formula (3)^FiveSame as
Righteousness, Ar¹And Ar^TwoAre each independently substituted
Represents an aryl group which may be
Each independently represents 0 or 1, and Q represents -CR¹¹R¹²−,
-O-, -S-, -NR¹³−, − SiR¹⁴R^FifteenAnd -C
A crosslinking group selected from the group consisting of O-¹¹And R
^{1 Two}Are each independently a hydrogen atom, an alkyl having 1 to 12 carbons.
A kill group, a phenyl group, a tolyl group or an anisyl group,
R¹³, R¹⁴And R^FifteenAre each independently a hydrogen atom or a
A tyl group; n represents 0 or 1; Compound represented by)
Product, more specifically, 1,1'-biphenyl-2,2'-
Diyl- (2,6-di-t-butyl-4-methylphenyi
G) Phosphite and the like described in US Pat. No. 4,599,206.
Compound and 3,3'-di-t-butyl-5,5'-dimethyl
Toxi-1,1'-biphenyl-2,2'-diyl-
(2-t-butyl-4-methoxyphenyl) phosphite
And the like described in U.S. Pat.
It is.

[0015]

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(In the formula, R ⁶ represents a cyclic or acyclic optionally substituted trivalent hydrocarbon group.) As the compound represented by the formula (5), for example, 4-ethyl-2 , 6,7-Trioxa-1-phosphabicyclo-
And the compounds described in U.S. Pat. No. 4,567,306, such as [2,2,2] -octane.

[0017]

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(Wherein, R ⁷ has the same meaning as R ⁴ in formula (3), R ⁸ and R ⁹ each independently represent a hydrocarbon group which may be substituted, and a and b each represent 0-6
And the sum of a and b is 2 to 6, and X is (a +
b) a valent hydrocarbon group; Among the compounds represented by the formula (6), preferred are, 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] dioxaphosphevin described in JP-A-2-31497. Compound, or
Equation (7):

[0019]

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[0020] (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, Ar ¹ , Ar ² , Q, x,
y and n have the same meanings as in equation (4). And the compounds described in JP-A-62-116535 and the compounds described in JP-A-62-116587.

[0021]

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Wherein X, Ar ¹ , Ar ² , Q, x, y,
n has the same meaning as in formula (7), and R ¹⁸ is R in formula (3).
Synonymous with ⁴ . )

[0023]

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(Wherein R ¹⁹ and R ²⁰ each independently represent an aromatic hydrocarbon group, and at least one of the aromatic hydrocarbon groups has a carbon atom adjacent to the carbon atom to which the oxygen atom is bonded. Has a hydrogen group, m represents an integer of 2 to 4, each —OP (OR ¹⁹ ) (OR ²⁰ ) group may be different from each other, and X is an optionally substituted m-valent group. Among the compounds represented by the formula (9), for example, JP-A-5-17
No. 8779, 2,2′-bis (di-1-naphthyl phosphite) -3,3 ′, 5,5′-tetra-t-butyl-
JP-A-Hei 6-dimethyl-1,1'-biphenyl and the like
Those described in JP-A-10-45776 are preferred.

[0025]

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(Wherein, R ^{21 to} R ²⁴ each represent a hydrocarbon group which may be substituted. Even if these are independent of each other, R ²¹ and R ²² , R ²³ and R ²⁴ are W may represent a divalent aromatic hydrocarbon group which may have a substituent, L may be a saturated or unsaturated group which may have a substituent. The compound represented by the formula (10) is, for example, a divalent aliphatic hydrocarbon group.
The thing described in 8-259578 gazette is used.

[0027]

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(Wherein, 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 combine with 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 any of aromatic, aliphatic and alicyclic groups.

The above-mentioned compounds can be used as a ligand of a rhodium complex catalyst by mixing two or more kinds. Further, the above trivalent organic phosphorus compound and a pentavalent organic phosphorus compound such as triphenylphosphine oxide can be mixed and used. The rhodium complex catalyst may be formed in a hydroformylation reaction system or may be prepared in advance. The compound that supplies the metal rhodium is not particularly limited, but includes, for example, rhodium compounds such as rhodium acetate, rhodium trichloride, and rhodium nitrate, and preferably rhodium acetate. When the rhodium complex catalyst is prepared in advance, the rhodium compound, the above-mentioned trivalent organic phosphorus compound and oxo gas are easily treated in the presence of a solvent at usually 60 to 200 ° C. and normal pressure to 20 MPa. Can be adjusted. The solvent may be usually selected from the following reaction solvents for the hydroformylation reaction, and is preferably the same as the solvent actually used as the reaction solvent for the hydroformylation reaction. The ratio of the rhodium compound to the trivalent organic phosphorus compound in preparing the catalyst is usually 10 to 1000 as a molar ratio of phosphorus to rhodium.
It is 0, preferably 10-1000.

As the reaction solvent for the hydroformylation reaction, any solvent can be used as long as it dissolves the catalyst and does not adversely affect the reaction. Examples thereof include aliphatic hydrocarbons such as hexane, octane, and cyclohexane. Aromatic hydrocarbons such as toluene and xylene; alcohols such as butanol, octanol and polyethylene glycol;
Ethers such as triglyme; esters such as dioctyl phthalate can be used. In addition, aldehydes generated by the reaction and aldehyde condensates such as trimers and tetramers thereof can also be used. Furthermore, paraffin corresponding to the starting olefin can also be used.

The pressure of the oxo gas in the hydroformylation reaction varies depending on the starting olefin and the like, but the hydrogen partial pressure is usually 0.0001 to 20 MPa, preferably 0.01 to 10 MPa, more preferably 0.1 to 5 MPa, and the partial pressure of carbon monoxide. Is usually 0.0001 to 20 MPa, preferably 0.01 to 10 MPa, and more preferably 0.1 to 5 MPa. The hydrogen partial pressure / carbon monoxide partial pressure ratio is usually 0.1 to 100, preferably 0.1 to 10, and more preferably 1 to 6. The reaction temperature varies depending on the starting olefin, ligand, and the like. Usually 15-300 ° C, preferably 40-200
° C, more preferably in the range of 50 to 150 ° C, for example, when propylene is used as a raw material and phosphine is used as a ligand, it is usually 50 to 150 ° C, preferably 70 to 120 ° C, more preferably 90 to 150 ° C. It is in the range of 120 ° C. In addition, when propylene is used as a raw material and phosphite is used as a ligand, usually 40 to
150 ° C, preferably 50-100 ° C, more preferably 60-90 ° C
Range. The rhodium concentration is usually 0.001 to 5% by weight, preferably 0.001 to 1% by weight, and more preferably 0.001 to 0.1% by weight. As a reaction system, a continuous system is suitably used. A method for removing produced aldehyde from a reaction medium containing catalyst and a reaction medium containing catalyst and unreacted oxo gas and olefin flowing out of the reaction zone, a method for recovering or recycling unreacted raw materials, and a method for recovering a reaction medium containing catalyst. The method of recirculation and, if necessary, reactivation can be carried out by a commonly used method known per se. As the type of the reactor, a stirred tank type, a bubble column type, a tube type, a gas stripping type, or the like can be used.

In the method of the present invention, when the above-mentioned hydroformylation reaction is stopped, when the operation of the reactor is stopped,
After the supply of the olefin is stopped, it is necessary to start lowering the temperature while the olefin remains in the reaction solution. Preferably, the olefin remains in the reaction solution when the temperature is lowered by 5 ° C. from the reaction temperature, and more preferably, the olefin remains in the reaction solution when the temperature is lowered by 10 ° C. from the reaction temperature. It is particularly preferable that the olefin remains in the reaction solution at the end of the temperature drop. The term “operation stop” in the present invention refers to a series of operations including a temperature lowering operation from the stop of the supply of the olefin to the end of the temperature lowering of the reaction solution. After the operation is stopped, the reaction solution may be withdrawn from the reactor and stored in a tank or the like, or the gas phase in the reactor may be replaced with an inert gas such as nitrogen to store the reaction solution in the reactor. May be. Examples of the reaction solution to be preserved include an operation for separating and removing product aldehyde, an operation for replacing dissolved oxo gas with an inert gas, an operation for separating and recovering dissolved olefin, and an operation for removing a part of the solvent. May have passed.

The term "state in which the olefin remains in the reaction solution" means a state in which after the supply of the olefin is stopped, the reaction is not exhausted until the olefin is substantially consumed. Typically, the concentration of the residual olefin in the reaction solution is 0.0001 in olefin / rhodium molar ratio.
Or more, preferably 0.001 or more, more preferably 1.0 or more,
Particularly preferably, it is a state of 3.0 or more. Further, "at the end of cooling down" means, for example, at the time of starting the withdrawal when extracting the reaction solution from the reactor, or when the inert gas in the gas phase in the reactor is stored in the reactor without extracting the reaction solution. This is the time when the next operation after the temperature lowering operation is started, such as when the replacement is started.

In the present invention, the time from the stop of the supply of the olefin to the start of the temperature drop varies depending on the reaction conditions.
In order to keep the olefin in the reaction solution, specifically, usually within 5 hours, preferably 10 minutes to
5 hours, more preferably 10 minutes to 1 hour. According to the above-described method, a reaction solution containing a rhodium complex catalyst in which deterioration is suppressed can be obtained.

[0035]

EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples unless it exceeds the gist. Example 1 Preparation of catalyst solution: 6 ml of a 10% aqueous solution of rhodium acetate diluted 20 times with methanol and a toluene solution of triphenylphosphine (TPP) (TPP concentration: 950 mm)
ol / l) of 50 ml was placed in a 200 ml internal / output stirring type autoclave. After the autoclave was replaced with nitrogen gas, oxo gas (H ₂ /CO=1.0 (molar ratio)) was injected, the temperature was raised to 115 ° C., and a carbonylation reaction was carried out at a constant pressure of 4.4 MPaG for 3 hours to obtain rhodium. The catalyst solution was prepared. The rhodium concentration of the obtained catalyst solution was 500 mg / l and the TPP concentration was 850 mm.
ol / l. Hydroformylation reaction: 50 ml of catalyst solution and propylene 1 after purging the induction stirring type autoclave with nitrogen.
0.5 g (0.249 mol) was charged. Oxo gas (H ₂ /CO=1.0 (molar ratio)) was injected, and the temperature in the reactor was raised to 120 ° C., and the pressure was maintained at 4.9 MPaG with a pressure regulator, and the hydroformylation reaction was performed at 120 ° C. for 2 hours. I let it. The reaction rate constant was calculated from the reduction rate of oxo gas in the accumulator. As a result, the reaction rate constant / rhodium concentration =
0.0251 [(1 / Hr) / (mg / l)]. The concentration of propylene in the reaction solution at this time was measured by gas chromatography and was found to be 0.03% by weight.

Temperature lowering operation: The temperature in the reactor was lowered to 60 ° C., and the mixture was continuously stirred at a constant temperature in an oxo gas atmosphere for 17 hours, and then cooled to 40 ° C. After the temperature was lowered, the propylene concentration in the reaction solution was measured by gas chromatography and found to be 0.025% by weight. The propylene / rhodium molar ratio at this time was 1.30. Catalyst activity check; about 50 ml of a catalyst solution obtained by distilling off the aldehyde generated from the above reaction solution, 100 ml of a toluene solution of TPP (TPP concentration: 950 mmol / l), and propylene in a vertically stirred autoclave having an internal volume of 500 ml. 5 g was charged at room temperature. At this time, the rhodium concentration was 180 mg / l. Oxo gas (H ₂ / CO =
1.0 (molar ratio)), and the temperature in the reactor was set to 120 ° C.
To oxo gas (H ₂ /CO=1.0)
(Molar ratio)) and the pressure in the reactor was 4.9 MPaG
, A hydroformylation reaction was carried out at 120 ° C for 3 hours. As a result, the reaction rate constant / rhodium concentration = 0.
0243 [(1 / Hr) / (mg / l)].

In the hydroformylation reaction of Example 2, the temperature in the reactor was 9
The procedure was the same as in Example 1 except that the temperature was lowered to 0 ° C. As a result, the reaction rate constant / rhodium concentration = 0.0240
[(1 / Hr) / (mg / l)]. In the hydroformylation reaction of Example 3, the temperature in the reactor was set to 1
The reaction was carried out in the same manner as in Example 1 except that the temperature was lowered to 00 ° C. As a result, the reaction rate constant / rhodium concentration =
0.0233 [(1 / Hr) / (mg / l)]. Comparative Example 1 After the induction-stirring type autoclave was replaced with nitrogen, about 50 ml of a catalyst solution prepared in the same manner as in Example 1 was charged, oxo gas (H ₂ /CO=1.0 (molar ratio)) was injected, and the temperature in the reactor was reduced. The temperature was raised to 120 ° C., and continuous stirring was performed at 120 ° C. for 17 hours under an oxo gas atmosphere at a constant temperature while maintaining the pressure at 4.9 MPaG with an accumulator. The activity of the catalyst was examined in the same manner as in Example 1. As a result, the reaction rate constant / rhodium concentration was 0.0169 [(1 / Hr) / (mg / l)].

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C07B 61/00 300 C07B 61/00 300 (72) Inventor Hiroki Kawasaki 3-chome Utsudori, Kurashiki City, Okayama Prefecture Mitsubishi Chemical Corporation Mizushima Plant F-term (reference) 4H006 AA02 AC29 AC45 BA24 BA48 BC10 BC34 BC40 4H039 CA62 CL45

Claims (8)

[Claims] 1. A method for shutting down a continuous hydroformylation reactor in which an olefin and an oxo gas are continuously supplied to a reaction medium containing a rhodium complex catalyst to form an aldehyde, wherein the supply of the olefin is stopped. A method of shutting down the operation, wherein in the step of lowering the temperature of the reaction medium containing the rhodium complex catalyst, the temperature is started while olefin remains in the reaction medium. 2. The method according to claim 1, wherein the residual amount of olefin at the start of cooling is not less than 1.0 in terms of olefin / rhodium molar ratio. 3. A method for shutting down a continuous hydroformylation reactor in which an olefin and an oxo gas are continuously supplied to a reaction medium containing a rhodium complex catalyst to produce an aldehyde, wherein the supply of the olefin is stopped. A method for shutting down the operation, characterized in that, in the process of lowering the temperature of the reaction medium containing the rhodium complex catalyst, olefin remains in the reaction medium when the temperature is lowered by 5 ° C. from the reaction temperature. 4. A method for shutting down a continuous hydroformylation reactor in which an olefin and an oxo gas are continuously supplied to a reaction medium containing a rhodium complex catalyst to form an aldehyde, wherein the supply of the olefin is stopped. A method for shutting down the operation, characterized in that, in the process of lowering the temperature of the reaction medium containing the rhodium complex catalyst, olefin remains in the reaction medium when the temperature is lowered by 10 ° C. from the reaction temperature. 5. A method for shutting down a continuous hydroformylation reactor in which an olefin and an oxo gas are continuously supplied to a reaction medium containing a rhodium complex catalyst to form an aldehyde, wherein the supply of the olefin is stopped. The method according to any one of claims 1 to 4, wherein in the step of lowering the temperature of the reaction medium containing the rhodium complex catalyst, the temperature lowering is terminated in a state where the olefin remains in the reaction medium. Method. 6. The method according to claim 1, wherein the residual amount of olefin at the end of cooling is 0.001 or more in terms of olefin / rhodium molar ratio. 7. The method according to claim 1, wherein the residual amount of olefin at the end of the temperature drop is 1.0 or more in terms of olefin / rhodium molar ratio. 8. The method according to claim 1, wherein the olefin is propylene.
The method according to any one of claims 1 to 7,