JPH0433779B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for hydroformylating olefins. Specifically, the present invention relates to a method for suppressing the production of high-boiling byproducts during the hydroformylation reaction of olefins. [Prior Art] A method for producing aldehydes by subjecting an olefinic compound to a hydroformylation reaction with carbon monoxide and hydrogen in the presence of a catalyst is well known. In particular, in the hydroformylation of branched olefinic compounds, the hydroformylation reaction is carried out using a rhodium catalyst modified with the oxide of a trivalent organic phosphorous compound, and the resulting reaction product is separated by distillation to produce aldehyde. A method has been proposed in which the rhodium catalyst is obtained by distillation, and the bottoms containing the rhodium catalyst are circulated to the hydroformylation reaction section (Japanese Patent Application Laid-Open No. 1983-1999).
76034 etc.). [Problems to be Solved by the Invention] However, when the hydroformylation reaction is continued for a long time using the above-mentioned proposed method, high boiling point by-products produced during the hydroformylation reaction, such as trivalent aldehyde, are produced. Not only does the production of acetals, acetals, etc. increase gradually, reducing the yield of aldehydes, but also these high-boiling byproducts accumulate in the circulating catalyst liquid, eventually making it impossible to operate the system with a certain capacity. cause problems. These problems can be solved by extracting the circulating catalyst liquid from outside the reactor in proportion to the amount of high-boiling by-products produced, and then supplying a new catalyst to the reactor equal to the amount of catalyst extracted. If a large amount of high-boiling byproducts are produced during the above hydroformylation reaction, the amount of catalyst liquid extracted will also increase, and the cost of recovering the catalyst from the extracted catalyst liquid (catalyst recovery cost) will increase, although it is not industrially advantageous. do not have. [Means for Solving the Problems] In order to solve the above-mentioned problems of the prior art, the present inventors have conducted extensive studies on a method for suppressing the production of high-boiling byproducts during hydroformylation reactions, and have found that By carrying out the hydroformylation reaction by reducing the proportion of alcohol from the circulating catalyst liquid in the charging liquid consisting of the olefinic compound and the catalyst liquid to the reaction system to a specified proportion or less, the production of the above-mentioned high-boiling by-products is significantly reduced. They discovered this and completed the present invention. That is, an object of the present invention is to provide a hydroformylation method in which the production of high-boiling byproducts is suppressed during the hydroformylation reaction of olefin using a rhodium catalyst. A hydroformylation reaction step in which an olefinic compound is reacted with carbon monoxide and hydrogen in a catalyst solution containing aldehyde. A distillation step of separating a distillate fraction and a non-distillate fraction consisting of a high boiling point component containing rhodium, and an oxidation step of oxidizing the non-distillate fraction obtained from this distillation step to convert trivalent organic phosphorus compounds into oxides. and a circulation step in which the treatment liquid obtained from the oxidation step is circulated as a circulating catalyst liquid to the hydroformylation reaction step, in which the olefinic compound is supplied to the hydroformylation reaction step. and the hydroformylation reaction is carried out under conditions in which the proportion of the alcohol contained in the circulating catalyst liquid and supplied is maintained at 14% by weight or less with respect to the total supply amount of the catalyst liquid. hydroformylation method,
Additionally, a hydroformylation reaction step in which an olefinic compound is reacted with carbon monoxide and hydrogen in a catalyst solution containing rhodium and an oxide of a trivalent organic phosphorous compound, and a trivalent organic phosphorus compound is added to the reaction solution obtained in the above step. An organic phosphorus compound is added and distilled in the presence of oxygen, separating the distillate containing aldehydes and the non-distillate fraction containing high boiling points containing rhodium, and oxidizing the trivalent organic phosphorus compound to form oxides. In the method for hydroformylating olefins, the method includes an oxidative distillation step for conversion, and a circulation step for circulating the non-distillate fraction obtained from the oxidative distillation step as a circulating catalyst liquid to the hydroformylation reaction step. The hydroformylation reaction is carried out under conditions that maintain the proportion of the alcohol contained in the circulating catalyst liquid and supplied to the total amount of the olefinic compound and catalyst liquid supplied to the process to be 14% by weight or less. The present invention provides a method for hydroformylating olefins, characterized by carrying out the following steps. The present invention will be explained in more detail below. In the first step of the method of the present invention, the hydroformylation reaction itself is carried out according to a conventional method. Usually, a solution containing rhodium and an oxide of a trivalent organic phosphorus compound, which is recycled from a subsequent circulation process, is used as a catalyst liquid, and the reaction is carried out by supplying an olefinic compound, carbon monoxide, and hydrogen to this solution. A catalyst and a solvent can be additionally supplied if desired. The catalyst can be prepared in the reaction system by adding a rhodium compound and, if desired, an oxide of a trivalent organic phosphorus compound to this hydroformylation reaction step, but the catalyst can be prepared in advance by adding a rhodium compound and an oxide of a trivalent organic phosphorus compound to the hydroformylation reaction step. It is preferable to mix them in a solvent and introduce carbon monoxide into the mixture to form an active rhodium catalyst before adding it to the reaction system. Rhodium compounds used for catalyst preparation include inorganic acid salts such as rhodium nitrate and rhodium sulfate; organic acid salts such as rhodium acetate, rhodium sodium oxalate, and rhodium potassium malate; [RhL ₆ ]X ₃ , [RhL ₅
(H ₂ O)]X ₃ , [RhL ₅ (OH)]X ₂ , [RhL ₅ (NO ₂ )]
X ₂ , [Rh(Py) ₃ (NO ₃ ) ₂ ] (wherein, X is NO ^- ₃ ,
Examples include amine complex salts such as OH ^- , 1/2 (SO ^2- ₄ ), L represents NH ₃ , and Py represents pyridine. Among them, rhodium nitrate and rhodium acetate are preferably used. Examples of oxides of trivalent organic phosphorus compounds include arylphosphine oxides such as triphenylphosphine oxide, tritolylphosphine oxide, and trianisylphosphine oxide; alkylphosphine oxides such as tributylphosphine oxide and trioctylphosphine oxide; in oxide;
An alkylarylphosphine oxide having both an alkyl group and an aryl group is used. Also,
Aryl phosphite oxides such as triphenyl phosphite oxide (i.e. triphenyl phosphate), tritolyl phosphite oxide; alkyl phosphite oxides such as triethyl phosphite oxide, tripropyl phosphite oxide, tributyl phosphite oxide; alkyl groups and aryl Alkylaryl phosphite oxides having a combination of groups and groups are also used. Furthermore, bis(diphenylphosphino)methane dioxide, 1,
2-bis(diphenylphosphino)ethane dioxide, 1,4-bis(diphenylphosphino)butane dioxide, 1,2-bis(diphenylphosphinomethyl)cyclobutane dioxide, 2,3
Polydentate phosphine oxides such as -O-isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane dioxide can also be used. The oxides of these trivalent organophosphorus compounds are
In the hydroformylation reaction system, 1 or more atoms of phosphorus in the oxide state are present per 1 atom of rhodium, usually 1 to 1000 atoms, preferably 10 to 1000 atoms, and more preferably 10 to 500 atoms. . In addition, in order to prepare an active catalyst from a rhodium compound and an oxide of a trivalent organic phosphorus compound,
Both may be mixed in the above ratio and treated with carbon monoxide. The conditions are carbon monoxide partial pressure 1~
200Kg/cm ² , preferably 1~10Kg/cm ² , temperature 10~
200℃, preferably 20-150℃, time 1-100 minutes,
Preferably, the time is appropriately selected from the range of 2 to 50 minutes.
Note that it is preferable to use carbon monoxide that does not substantially contain hydrogen. The catalyst concentration in the reaction zone is usually 1 to 500 mg/, preferably 2 to 100 mg/ of rhodium. Examples of olefinic compounds used in the hydroformylation reaction include ethylene, propylene,
- Straight chain α- with 30 or less carbon atoms such as butene, 1-pentene, 1-hexene, 1-octene, 1-decene, etc.
Olefins; 2-butene, 2-pentene, 2-
Linear internal olefins such as hexene, 3-hexene, 2-octene, 3-octene; isobutylene, 2-methyl-1-butene, 2-methyl-1-
Pentene, 3-methyl-1-pentene, 2-methyl-1-hexene, 3-methyl-1-hexene,
Branched α- such as 2-methyl-1-heptene, 3-methyl-1-heptene, 4-methyl-1-heptene, etc.
Olefins; 2,3-dimethyl-1-butene,
2,3-dimethyl-1-pentene, 2,4-dimethyl-1-pentene, 2,3-dimethyl-1-hexene, 2,4-dimethyl-1-hexene, 2,
Examples include hyperbranched α-olefins such as 5-dimethyl-1-hexene and 3,4-dimethyl-1-hexene; and double bond isomers thereof. Further, isomer mixtures such as dimers to tetramers of propylene, butene, isobutylene, etc., and olefins having substituents such as allyl alcohol, acrolein acetal, vinyl acetate, styrene, and alkyl vinyl ether can also be used. can. In particular, the method of the present invention is advantageous for the hydroformylation of octenes obtained by dimerizing a C4 fraction (hereinafter referred to as BB fraction) obtained in large quantities from the thermal cracking of naphtha or the catalytic cracking of heavy and light oils. applied to. This is because these are branched internal olefins or mixtures mainly composed of them, but
This is because, unlike the case of using a rhodium catalyst modified with an organic phosphine, in the method of the present invention using the oxide of a trivalent organic phosphorus compound, the reaction proceeds quickly even when a mixture of these isomers is used as a raw material. . In the method of the present invention, as described above, a solution containing rhodium and an oxide of a trivalent organic phosphorus compound recycled from the circulation step is used as a reaction medium, but an additional solvent may also be used. Any solvent can be used as long as it dissolves the catalyst and does not adversely affect the reaction. For example, aromatic hydrocarbons such as benzene, toluene, xylene, and dodecylbenzene; alicyclic hydrocarbons such as cyclohexane; dibutyl ether, ethylene glycol dimethyl ether,
Ethers such as diethylene glycol diethyl ether, triethylene glycol dimethyl ether, and tetrahydrofuran; diethyl phthalate,
Esters such as dioctyl phthalate and bis(2-ethylhexyl) phthalate are used. Moreover, the aldehyde itself produced by the hydroformylation reaction can also be used as a solvent. A higher reaction temperature is advantageous in terms of reaction rate, but if the temperature is too high, there is a risk that the catalyst will decompose. Therefore, it is usually preferable to carry out the reaction at a temperature of 50 to 170°C, particularly 100 to 150°C. The carbon monoxide and hydrogen gases used in the hydroformylation reaction are preferably water gases in which the molar ratio of hydrogen to carbon monoxide is in the range of 1/5 to 5/1, particularly 1/2 to 2/1. Partial pressure of water gas is 20-500Kg/cm ²
is used, preferably 50 to 300Kg/
It is in the ^cm2 range. The reaction can be carried out either continuously or batchwise. In the method of the present invention, the hydroformylation reaction is carried out using an olefinic compound (including a newly supplied olefinic compound and a circulating olefinic compound) and a catalyst liquid (including a newly supplied catalyst liquid and a circulating olefinic compound) supplied to the reaction step. The content of alcohol contained in the circulating catalyst liquid (hereinafter referred to as the alcohol content from the circulating catalyst liquid) relative to the total amount of supplied liquid (including liquid) (hereinafter referred to as the amount of charged liquid) This is carried out under conditions that maintain the proportion of 14% by weight or less, preferably 10% by weight or less, and more preferably 5% by weight or less. The above-mentioned alcohol to be controlled in the present invention refers to the alcohol produced by hydrogenation of the aldehyde produced by the hydroformylation reaction of the olefinic compound as a raw material (that is, the alcohol corresponding to the produced aldehyde). . In addition, in the continuous operation of a hydroformylation reaction plant, when the catalyst liquid does not substantially contain alcohol at the start of operation or during a limited period in the initial stage of operation, or when alcohol is contained in the catalyst liquid from the circulating catalyst liquid. The content is 14% relative to the amount of prepared liquid.
Although the amount may be less than % by weight, the method of the present invention does not include these cases. However, even in these cases, if normal industrial hydroformylation reaction conditions are adopted and continuous operation is performed without adjusting the alcohol content, the above-mentioned amount will be added to the circulating catalyst solution in about one day. 14% by weight
Since a larger amount of alcohol accumulates than the previous one, control by the method of the present invention is performed. Under conditions where the alcohol content from the circulating catalyst liquid exceeds 14% by weight with respect to the amount of the charged liquid, high-boiling by-products during the hydroformylation reaction,
For example, the production of aldehyde condensates such as dimers and trimers, which are self-condensates of the aldehyde produced, and acetals increases significantly, which is undesirable because the yield of the aldehyde produced decreases. As a method for adjusting the alcohol content ratio, for example, when distilling aldehyde from the reaction product liquid obtained in a hydroformylation reaction, distillation conditions are selected so that the alcohol concentration in the bottoms is below a specific concentration. Examples include a method in which the amount of olefin is adjusted by extracting a part of the circulating catalyst liquid, and a method in which the ratio between the amount of charged (supplied) olefin and the amount of the circulating catalyst liquid is adjusted. In the second step of the method of the present invention, a trivalent organic phosphorus compound is added to the reaction solution of the hydroformylation reaction and then distilled to distill out the aldehyde or alcohol produced by the reaction. As the trivalent organic phosphorus compound, it is preferable to use one that corresponds to the oxide in the catalyst solution for the hydroformylation reaction. Usually, triphenylphosphine, tributylphosphine, etc. are preferably used. The trivalent organic phosphorus compound is placed on the rhodium catalyst in the reaction solution to stabilize it. The trivalent organic phosphorus compound is added so that one atom or more of trivalent phosphorus per one atom of rhodium. However, even if a large amount is used, the stability of the catalyst does not increase in proportion to the amount used, so usually one to one trivalent phosphorus is used for one atom of rhodium.
It is added in an amount of 100 atoms, preferably 1 to 20 atoms. The reaction solution of the hydroformylation reaction to which a trivalent organic phosphorus compound is added is a distillate fraction containing low-boiling fractions such as aldehydes and alcohols produced by distillation using a conventional method, and a non-distillate fraction containing high-boiling fractions containing a rhodium catalyst. It is separated into distillate and distillate. Since the rhodium catalyst in the reaction solution is stabilized by a trivalent organic phosphorus compound, it can be used for flash distillation, atmospheric distillation, vacuum distillation, and combinations thereof. Any distillation method can be used. Further, the distillation temperature is usually 200°C or lower, particularly preferably 25 to 150°C. In the third step of the method of the present invention, the rhodium catalyst and the oxide of the trivalent organic phosphorus compound discharged as the bottom liquid from the distillation step, as well as the high boiling point component containing the above-mentioned trivalent organic phosphorus compound, are acidified and converts a valent organophosphorus compound into the corresponding oxide.
Usually, this oxidation is carried out by blowing atmospheric pressure air into the high boiling point. The conditions are usually appropriately selected from the range of a temperature of 20 to 200°C, preferably 20 to 150°C, and a time of 1 minute to 5 hours, preferably 5 minutes to 2 hours. The purpose of this treatment is to convert the trivalent organic phosphorus compounds in the high boiling point fraction into the corresponding oxides, but it is not necessary to convert all of the trivalent organic phosphorus compounds into the corresponding oxides. The air acid value of the trivalent organic phosphorus compound can also be determined in the distillation column in the second step, in which case the second step becomes an oxidative distillation step. That is, by distilling while introducing a small amount of air into the distillation column, distillation and oxidation of the trivalent organic phosphorus compound can be performed simultaneously. For example, in a vacuum distillation column, there is generally some air leakage, but even with this amount of air, the oxidation of the trichemical organic phosphorus compound proceeds. In addition, if the oxidation does not proceed sufficiently in the tower, the high boiling point component discharged as the tower bottom liquid may be air-oxidized again as described above. In the final step of the method of the present invention, the oxidized high-boiling solution is recycled to the hydroformylation reaction step and used as the catalyst solution or a part thereof. Note that high boiling point by-products and phosphorus compounds produced by the reaction accumulate in this high boiling point fraction, so some of them are continuously or intermittently discharged to the outside of the system to maintain a constant concentration of these in the system. It is preferable to maintain [Examples] Next, embodiments of the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded. Examples 1 to 4 and Comparative Examples 1 to 3 (1) Synthesis of raw material olefin After removing butadiene and isobutene from the BB fraction obtained from a naphtha cracker
_C4 fraction (6% by weight of isobutene, 43% by weight of 1-butene, 25% by weight of 2-butene, 25% by weight of butanes,
Other 1% by weight composition) with molecular sieve
Dehydrated by 13X. Next, 4 kg of the dehydrated C ₄ fraction described above and 5.5 g of an n-hexane solution of nickel octoate (ni content 6 wt) were placed in a SUS induction stirring autoclave with an internal volume of 10 in a nitrogen atmosphere.
%) and 11.3 g of ethylaluminum diloride were charged and reacted at 40°C for 7 hours. After the reaction, 340 g of a 5 wt% H ₂ SO ₄ aqueous solution was added to deactivate the catalyst, followed by liquid-liquid separation, followed by atmospheric distillation to obtain a C ₈ olefin mixture (hereinafter referred to as octene). The above reaction and distillation were carried out three times. (2) Hydroformylation reaction A methanol solution of octene 7 obtained in (1) above and rhodium acetate (rhodium concentration 4000 mg/
) was added in an amount such that the rhodium concentration in the reaction solution was 10 mg/2, and triphenylphosphine oxide was added in an amount of 20 times the molar amount of rhodium, and the autoclave was sealed. After replacing the inside of the autoclave with nitrogen gas, further pressurizing nitrogen gas to 40Kg/cm ² G, and then releasing the pressure to normal pressure three times,
The temperature was raised to 130℃. Immediately after reaching 130℃, the total pressure is reduced.
Water gas ( _{H 2} ^/ CO=
1) was pressurized and the reaction was carried out at 130°C for 6 hours.
During this time, the water gas consumed by the reaction is replenished from the pressure accumulator via a constant pressure device, and the water gas is fed into the autoclave.
It was maintained at 170Kg/cm ² G. After the reaction was completed, the reaction solution was analyzed by gas chromatography, and the results showed that C ₉
Aldehyde yield 92.72%, _C9 alcohol yield 4.90
%, and the high boiling point by-product conversion rate was 0.40%. (3) Distillation of the hydroformylation reaction solution In the hydroformylation reaction solution obtained in (2) above,
Add triphenylphosphine in an amount 9 times the mole of rhodium in the reaction solution, and heat at a pressure of 70 mm in an air atmosphere.
Simple distillation of Hg was carried out at a tower top temperature of 110° C. to distill off the aldehyde, and a distillation residue containing alcohol was obtained as the bottoms. This distillation residue was oxidized by holding it at 140° C. for 2 hours under normal pressure in an air atmosphere to obtain a treated solution (hereinafter referred to as circulating catalyst solution A). Further, a part of the circulating catalyst liquid A was distilled under reduced pressure in a nitrogen atmosphere at a pressure of 30 mmHg and a column top temperature of 115°C,
90% by weight of the alcohol contained was distilled off to obtain a bottoms liquid (hereinafter referred to as circulating catalyst liquid B). (4) Hydroformylation reaction using circulating catalyst liquid The octene obtained in (1) above and (3) above were placed in a top-down stirring autoclave made of SUS-316 with an internal volume of 200 ml.
The circulating catalyst liquid A or B obtained in the above was supplied in the proportions shown in Table 1, and the autoclave was sealed. After purging the inside of the autoclave with nitrogen gas, further pressurizing nitrogen gas to 40 kg/cm ² , and then releasing the pressure to normal pressure, the operation was repeated three times, and then the temperature was raised to 130°C. Immediately after reaching 130℃, the total pressure becomes 170Kg/cm ²
Water gas (H ₂ /CO=1) was introduced under pressure so that the reaction temperature was 130° C. until the conversion of octene exceeded 95%. During this time, the water gas consumed by the reaction was replenished from the pressure accumulator via the constant pressure device, and the inside of the autoclave was maintained at 170 kg/cm ² G. After the reaction was completed, the reaction solution was analyzed by gas chromatography. Table 1 shows the alcohol concentration in the charged liquid (=ratio of the alcohol content from the circulating catalyst liquid to the amount of the charged liquid), the aldehyde yield after the reaction, the alcohol yield, and the high-boiling byproduct conversion rate.

【table】

〔Effect of the invention〕

By the method of the present invention, it is possible to effectively suppress the production of high-boiling byproducts during the hydroformylation reaction of olefins.

Claims (1)

[Claims] 1. A hydroformyl reaction step in which an olefinic compound is reacted with carbon monoxide and hydrogen in a catalyst solution containing rhodium and an oxide of a trivalent organic phosphorus compound, and a reaction solution obtained in the above step. A distillation process in which a trivalent organic phosphorus compound is added to the water and distilled to separate the distillate containing aldehyde and the non-distillate fraction consisting of high boiling point components containing rhodium, and the non-distillate fraction obtained from this distillation process. an oxidation step of converting a trivalent organic phosphorus compound into an oxide, and a circulation step of circulating the treated solution obtained from this oxidation step to the hydroformylation reaction step as a circulating catalyst solution. In the hydroformylation method, the proportion of the alcohol contained in the circulating catalyst liquid and supplied to the total amount of the olefinic compound and catalyst liquid supplied to the hydroformylation reaction step is 14% by weight or less. 1. A method for hydroformylating olefins, characterized in that the hydroformylation reaction is carried out under maintained conditions. 2. The method for hydroformylating olefins according to claim 1, characterized in that the non-distillate fraction consisting of high boiling points containing rhodium obtained from the distillation step is air oxidized in the oxidation step. 3. The method for hydroformylating olefins according to claim 1 or 2, wherein the olefinic compound is a branched internal olefin or a mixture mainly composed of this. 4. The method for hydroformylating olefins according to claim 1 or 2, wherein the olefinic compound is a butene dimer. 5 A hydroformylation reaction step in which an olefinic compound is reacted with carbon monoxide and hydrogen in a catalyst solution containing rhodium and an oxide of a trivalent organic phosphorus compound, and a trivalent organic phosphorus compound is added to the reaction solution obtained in the above step. A phosphorus compound is added and distilled in the presence of oxygen.
An oxidative distillation process in which a distillate containing aldehyde and a non-distillate fraction consisting of a high boiling point containing rhodium are separated, and a trivalent organic phosphorus compound is oxidized and converted into an oxide; and the non-distillate obtained from this oxidative distillation process. In an olefin hydroformylation method including a circulation step in which the distillate is circulated as a circulating catalyst liquid to the hydroformylation reaction step, the total amount of the olefinic compound and catalyst liquid supplied to the hydroformylation reaction step. In contrast, a method for hydroformylating olefins, characterized in that the hydroformylation reaction is carried out under conditions in which the proportion of alcohol contained in the circulating catalyst liquid and supplied is maintained at 14% by weight or less. 6. The method for hydroformylating olefins according to claim 5, wherein the olefinic compound is a branched internal olefin or a mixture mainly composed of this. 7. The method for hydroformylating olefins according to claim 5, wherein the olefinic compound is a butene dimer.