JPH0129778B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for hydroformylating olefins. More specifically, the generated aldehyde is obtained by hydroformylation reaction of olefins using a rhodium complex as a catalyst in an organic solvent that is immiscible with water, from a reaction mixture containing a rhodium complex, an organic solvent, etc. The present invention relates to a method for separating and recovering organic solvents and residual organic solvents containing catalysts. In the hydroformylation reaction of olefins using an expensive rhodium complex as a catalyst, it is necessary to efficiently recover the catalyst from the catalyst-containing reaction mixture after the reaction, regenerate it, and use it again as a catalyst.
Establishing a technology for a catalyst circulation and reuse system is an extremely important issue in order to make this reaction an industrial process. In the hydroformylation reaction using a rhodium complex as a catalyst, several methods have been proposed to recover the rhodium catalyst from the reaction mixture obtained after the reaction and reuse it. (1) A method of separating the product and the catalyst by evaporation or distillation. (Japanese Unexamined Patent Publication No. 125103/1983) (2) A method of extracting and separating generated aldehydes with a polar solvent such as water. (JP-A-51-294112 and JP-A-53-68709) (3) A method in which a rhodium complex is decomposed into a metal form using hydrogen, steam, acid, etc., and the metal is precipitated and recovered. (4) Using silicone rubber membrane, cellulose membrane, etc.
A method for membrane separation of rhodium complexes. (Unexamined Japanese Patent Publication 1973-
7365 and Japanese Patent Publication No. 49-24882) (5) A method of coordinating a rhodium complex to a polymer compound having coordinating ability and recovering it. (Japanese Patent Publication No. 48-28273) etc. are conventionally known methods for recovering catalysts in hydroformylation reactions using rhodium complexes as catalysts. When the product is a lower aldehyde with a relatively small number of carbon atoms, such as propionaldehyde or butyraldehyde, the boiling point of the product is relatively low;
Since it is easily volatile, the generated aldehydes are continuously extracted along with a large amount of raw material gas from the reaction zone at the same time as the reaction, or the generated aldehydes are separated by distillation from the catalyst solution after the reaction is completed, and the remaining catalyst-containing solution is removed. and can be returned to the reaction zone and reused. Such a method is in practical use, for example, for the industrial production of butyraldehyde from propion. In addition, if the product is an aldehyde that has a polar functional group such as a hydroxyl group in its molecule and has high solubility in polar media such as water or polyhydric alcohol, organic By carrying out the hydroformylation reaction in a solvent and contacting the reaction mixture containing the product obtained by the reaction with a polar medium such as water or polyhydric alcohol, only the generated aldehyde is separated from the reaction mixture, and the catalyst is removed. It is possible to circulate the remaining organic solvent phase contained back into the reaction zone. Such a method is applied, for example, to a method for producing hydroxybutyraldehyde, which is a precursor of 1,4-butanediol, by hydroformylation of allyl alcohol. These two methods are advantageous in that they can easily separate the catalyst and products, do not require complicated activation and regeneration of the catalyst, and have little loss of catalyst components, and are suitable for industrial use. This is an interesting method. However, the former method has a limit on the distillation temperature in order to suppress the deterioration and deterioration of the catalyst during the distillation operation and the decrease in activity, and therefore it is only allowed for aldehydes with relatively low boiling points, and the latter method is This method is effective only for aldehydes that have high solubility in polar solvents such as water. As the number of carbon atoms in the molecule increases, the volatility of aliphatic aldehydes decreases, the boiling point becomes high, and the solubility in polar solvents such as water rapidly decreases.
Therefore, both of the above two methods are unsuitable for producing higher aldehydes having a large number of carbon atoms. On the other hand, known methods other than the above include methods of decomposing rhodium complexes and recovering them in the form of metals or salts;
Membrane separation method using silicone rubber, cellulose, etc.
Alternatively, there is a recovery method by coordination with a polymer compound having coordination ability, but all of them involve a complicated separation and recovery process and an activation and regeneration process of the recovered catalyst, and also cause a large loss of catalyst components. The reality is that no satisfactory results have been obtained as an industrial hydroformylation reaction method. The present invention relates to a method for producing dialdehydes having low solubility in polar solvents such as water, high boiling points, and having 8 or more carbon atoms in the molecule. Such dialdehydes can be converted into diols, diamines, and dicarboxylic acids through operations such as hydrogenation, reductive amination, and oxidation.
It is a raw material for substances that have various uses such as polyester, polyamide, and epoxy resin curing agents, and is an extremely useful substance industrially. Dialdehydes with 8 or more carbon atoms in the molecule are
It has a relatively high boiling point and low solubility in polar solvents such as water. Furthermore, dialdehydes have the property of being more easily turned into resin-like substances by heating than monoaldehydes. Therefore, if an attempt is made to separate the produced aldehydes, mainly dialdehydes, from the reaction mixture by distillation, the heating temperature will become high and the rhodium complex will undergo decomposition and alteration, and some of the produced aldehydes will change in quality and become resinous. This results in the formation of a substance. Furthermore, even if an attempt is made to separate the aldehydes produced, mainly dialdehydes, by extracting the reaction mixture obtained by the reaction with a polar solvent such as water, this method is also difficult to implement due to its low solubility. be. The present inventors have overcome these drawbacks that occur when the conventionally known rhodium catalyst separation method is applied to the production of dialdehydes having 8 or more carbon atoms, and have developed a rhodium catalyst separation method that includes an efficient rhodium catalyst separation process. As a result of our earnest efforts to establish a method for producing aldehydes,
By converting dialdehydes into the form of alkali bisulfite adducts, their solubility in water increases,
As a result, extraction and separation into the aqueous phase becomes possible quantitatively, and surprisingly, almost no loss of catalyst components is observed during this operation, and no significant decrease in the activity of the rhodium catalyst is observed. They discovered this and completed the present invention. Normally, when monoaldehydes are brought into contact with an aqueous aqueous solution of bisulfite to form an alkali bisulfite adduct, the adduct becomes an adduct that is poorly soluble in both the aqueous solution and the organic solvent, making it extremely difficult to separate the organic and aqueous phases. However, in the case of the present invention, it is a completely unexpected result that the generated aldehydes can be transferred to the aqueous phase without precipitation of such insoluble solids.
That's surprising. That is, the present invention provides a method for treating non-conjugated diolefins having 6 or more carbon atoms or non-conjugated unsaturated aldehydes having 7 or more carbon atoms in the presence of a rhodium complex catalyst in an organic solvent that is immiscible with water, and in the presence of a rhodium complex catalyst. In a method for producing dialdehydes by hydroformylation through reaction with carbon oxide, after the hydroformylation reaction is completed, the reaction solution is brought into contact with an aqueous alkali bisulfite solution, and the resulting aldehydes, including the dialdehyde, are converted into an alkali bisulfite adduct. The organic solvent phase containing the catalyst and the aqueous phase containing an alkali bisulfite adduct of the produced aldehyde, mainly dialdehyde, are separated and recovered by extraction into an aqueous solution in the form of This is a method for producing dialdehydes. By the method of the present invention, the rhodium complex catalyst used in the hydroformylation reaction can be recovered together with the reaction solvent and recycled as is to the hydroformylation reaction zone. Therefore, the present invention enables the recycling and recycling of expensive rhodium complex catalysts in an extremely simple manner in the production of high molecular weight dialdehydes with high boiling points and low solubility in water, to which conventional methods cannot be applied. This makes it possible to economically produce industrially useful dialdehydes. Hereinafter, the specific content of the present invention will be explained. Raw Diolefin The raw diolefin used in the present invention is a non-conjugated diolefin having 6 or more carbon atoms. It is also applicable to non-conjugated diolefins having up to 5 carbon atoms, but since the dialdehydes obtained from such light diolefins have a low boiling point, it is possible and advantageous to separate the catalyst by distillation. .
Furthermore, when the number of carbon atoms in the raw material diolefin increases, the solubility of the alkali bisulfite adduct of aldehyde obtained by hydroformylation in water decreases, and the efficiency of extraction and separation decreases. Therefore, the number of carbon atoms in the raw material diolefins is up to 12 in the case of linear diolefins and 20 in the case of cyclic diolefins.
It is preferable that it is up to. Such non-conjugated diolefins can be obtained, for example, by a disproportionation reaction between cycloalkenes and ethylene. There are linear α,ω-diolefins such as 1,5-hexadiene, 1,6-heptadiene, 1,7-octadiene, 1,8-nonadiene, and 1,9-decadiene. Further, cyclic non-conjugated diolefins such as 1,5-cyclooctadiene, which are obtained as cyclic oligomers of dienes such as butadiene, can also be used as raw materials in the present invention. A non-conjugated diolefin which is particularly advantageous as a raw material used in the present invention has a bridgehead carbon in the molecule and has 2
These are bridged alicyclic diolefins in which two olefinic double bonds are present on both sides of a bridgehead carbon, such as dicyclopentadiene, norbornadiene, and 5-vinyl-2-norbornene. Raw Material Nonconjugated Unsaturated Aldehyde As the raw material in the method of the present invention, unsaturated aldehydes in which one of the two olefinic double bonds of the nonconjugated diolefin has already been hydroformylated can be used. Such unsaturated aldehydes have an olefinic double bond and a carbonyl group that are not in a conjugate position with each other, and the following unsaturated aldehydes are referred to as non-conjugated unsaturated aldehydes. Non-conjugated unsaturated aldehydes used as raw materials in the present invention are, for example, 1-formyl-5-hexene, 2-formyl-5-hexene, 1-formyl-7-octene, 2-formyl-7-octene, 1 -Formyl-9-decene, 2-formyl-
9-decene, 1-formyl-11-dodecene, 2-
Chain nonconjugated unsaturated aldehydes such as formyl-11-dodecene and 1-formyl-cyclooctene-
Examples include cyclic non-conjugated unsaturated aldehydes such as No. 4. The non-conjugated unsaturated dialdehyde which is particularly advantageous as a raw material for use in the present invention has a bridgehead carbon in the molecule, and an olefinic double bond and a formyl group are present on opposite sides of the bridgehead carbon. Bridged alicyclic unsaturated aldehydes, such as 5
-Formyl-norbornene-2,8-formyl-
Tricyclo[5.2.1.0 ^2,6decene -3,9-formyl-tricyclo[5.2.1.0 ^2,6decene -3, etc.] Catalyst The hydroformylation reaction of olefins is carried out in the presence of a catalyst consisting of a group organometallic complex, and the most suitable catalyst for carrying out the process of the present invention is a triarylphosphine as a ligand. A series of rhodium complex catalysts containing As the triarylphosphine used as a ligand, it is most preferable to use triphenylphosphine, but tri-p-tolylphosphine,
Tri-m-tolylphosphine, tris-(p-ethylphenyl)phosphine, or tris-
Triarylphosphines having attached substituents that are inert under the hydroformylation reaction conditions, such as lower alkyl or alkoxy groups, such as (p-methoxyphenyl)phosphine, can also be used in the process of the invention. In any case, as long as the rhodium complex catalyst is substantially insoluble in water and will not be converted into an unfavorable form when contacted with an aqueous alkaline bisulfite solution, any conventional rhodium-containing hydroformylation reaction Any catalyst can be used as a hydroformylation reaction catalyst in practicing this invention. Organic solvent The hydroformylation reaction solvent used in the present invention can be any organic solvent as long as it dissolves the rhodium catalyst and is immiscible with the aqueous alkali bisulfite solution, but usually aromatic solvents such as benzene, toluene, and xylene are used. Group hydrocarbons are highly preferred. Hydroformylation reaction The hydroformylation reaction conditions when carrying out the present invention include a temperature of 50 to 200°C, preferably 70 to 200°C.
The temperature is 150℃. Regarding the pressure, it is 30 to 200 Kg/cm ² , preferably 50 to 150 Kg/cm ² . The composition of the oxo gas used in the reaction is H ₂ /CO
= Can be changed arbitrarily within the range of 10/1 to 1/10,
Considering the reaction selectivity, H ₂ /CO=2/
Particularly preferred is 1 to 1/2. Furthermore, there is no problem in the hydrogen and carbon monoxide mixed gas containing gases that are inert to the reaction, such as nitrogen and methane. The catalyst concentration can be arbitrarily changed depending on the reaction conditions, etc., but in consideration of selectivity to dialdehydes, reaction rate, etc., it is usually preferable to carry out the reaction at a concentration of 0.5 to 10 mmol. The amount of triarylphosphines present in the reaction zone can be arbitrarily changed within a wide range of 3 to 300 mol per 1 mol of rhodium. The range of 10 to 100 moles per mole is preferred. Production of Aldehyde Aldehyde Alkali Bisulfite Adduct A reaction mixture containing dialdehyde-containing aldehydes, a rhodium-triarylphosphine complex, triarylphosphine, an organic solvent, etc. is brought into contact with an aqueous alkaline bisulfite solution. Any conventionally known extraction device and extraction technique can be used to extract only the generated aldehydes, which mainly contain aldehydes, in the form of an alkali bisulfite adduct into the aqueous phase. All of the above operations are performed in order to avoid deterioration of the complex catalyst, generated aldehydes, and alkali bisulfite.
It should be carried out in a state where it is isolated from substances that may have an oxidizing effect such as oxygen, and is usually carried out in an inert gas atmosphere such as nitrogen or argon. As needed,
It is also possible to carry out the above operations under an oxo gas atmosphere. The alkali bisulfite used may be sodium bisulfite, potassium bisulfite, cesium bisulfite, etc., but sodium and potassium bisulfites are preferred, and among these, sodium bisulfite is particularly preferred. The amount of alkali bisulfite to be used is determined by taking into account the amount of aldehydes produced in the reaction mixture, but since the adduct formation reaction is an extremely rapid reaction, the amount of alkali bisulfite used is determined by The amount of adduct produced is determined stoichiometrically accordingly. Therefore, in order to achieve quantitative adduct formation, at least 1 mol of alkali bisulfite is required per 1 mol of formyl group of the formed aldehyde in the reaction mixture. More than one mole of alkali bisulfite per mole of formyl group is usually used. Although there should be no restrictions on using an excessive amount of alkali bisulfite, there is no advantage to using an excess of alkali bisulfite than necessary, and it is not economically considered. The amount of alkali bisulfite normally used is based on the amount of formyl group of the formed aldehyde, including dialdehyde, contained in the reaction mixture.
It ranges from 1 to 3 moles per mole. The concentration of the aqueous alkali bisulfite solution to be used is determined by considering the distribution coefficient of the aldehyde alkali bisulfite adduct between the aqueous phase and the organic solvent phase, but usually the alkali bisulfite adduct in the aqueous phase It is desirable to determine the concentration of the alkaline bisulfite aqueous solution so that the concentration is 5% or more, preferably 10% or more. The adduct-forming reaction is carried out at a temperature of 0 to 50°C. Raising the temperature should be avoided because it increases the elution of the rhodium complex catalyst into the aqueous phase and may also lead to side reactions during this operation.
The preferred operating temperature is 0 to 30°C, but usually 15°C.
By carrying out this operation at room temperature of ~20 °C,
The objects of the present invention can be fully achieved. In the extraction separation operation, when the reaction mixture after the reaction has been completed and the aqueous alkali bisulfite solution are mixed and stirred, an addition reaction between the aldehyde and the alkali bisulfite occurs, and the temperature of the solution increases. When the temperature of the liquid drops with continued stirring, stop the stirring and leave it at room temperature, and separate the lower aqueous phase from the organic solvent phase containing the catalyst in the upper layer and the aqueous phase in which the adducts are dissolved in the lower layer. Drain and remove. An aqueous solution containing an alkali bisulfite adduct of the generated aldehyde is prepared by decomposing the adduct, for example with an alkali, or with formaldehyde, acetaldehyde, etc., which form bisulfite adducts more easily than the dialdehyde. can be separated. After the generated aldehydes are extracted and separated into an aqueous phase as an alkali bisulfite adduct, the organic solvent phase is substantially free of generated aldehydes and contains a rhodium-triarylphosphine complex, triarylphosphine, etc. Although it is possible to circulate it as it is to the hydroformylation reaction zone, it is preferable to wash it with water before circulating it to the hydroformylation reaction zone. The organic solvent phase containing the rhodium complex catalyst that has been treated by the method described above still has sufficient catalytic activity for the hydroformylation reaction, and the organic solvent phase containing the rhodium complex catalyst still has sufficient catalytic activity for the hydroformylation reaction. The desired dialdehyde can be obtained again by adding the following and carrying out the hydroformylation reaction under the above-mentioned conditions. EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded. Example 1 In an electromagnetic induction stirring autoclave with an internal volume of 200ml.
HRh (CO) (PPh ₃ ) ₃ 1.4m mol/, PPh ₃ 16m
mol/and dicyclobentadiene 1.7 mol/
Pour 110ml of toluene solution containing
After replacing the gas with a mixed gas of H ₂ /CO=1/1, the gas was further supplied until the pressure reached 60 Kg/cm ² G. This autoclave was then heated to a temperature of 100°C, held at that temperature for 2 hours, then further raised to 120°C and held for 1 hour, then heating was stopped and the autoclave was cooled to room temperature. Rapid gas absorption is seen from around 70℃, but during the above operation,
By replenishing the mixed gas of H ₂ /CO = 1/1, the pressure inside the autoclave can be reduced to 70Kg/cm ² G and 80Kg/cm 2 G.
It was kept between cm ² G. After cooling and purging the gas in the autoclave, the reaction mixture was taken out and analyzed. Dicyclopentadiene, a raw material, was not detected, but it contained 160 mmol of diformyltricyclodecane and 28 mmol of formyltricyclodecene. Next, the entire amount of the reaction solution was transferred under a nitrogen atmosphere to a 500 ml flask equipped with a stirrer and a thermometer, and an aqueous sodium bisulfite solution obtained by dissolving 40 g of sodium bisulfite in 200 ml of water was added thereto. When stirring is started at 15℃, the addition reaction of sodium bisulfite to the generated aldehyde proceeds, and the temperature increases from 15℃ to 35℃.
It rose to After returning to room temperature, it was separated into an upper organic solvent layer and a lower aqueous phase, and analysis of the upper layer revealed that it contained almost no diformyltricyclodecane and formyltricyclodecene, which are the aldehydes produced.
Furthermore, analysis of the lower layer revealed that the rhodium concentration was 0.9 ppm in terms of metal, and the organic phosphorus compound contained only 3 ppm in terms of elemental phosphorus. The results of this analysis showed that the catalyst rhodium triarylphosphine complex and triarylphosphine were hardly eluted into the aqueous phase, and only the generated aldehyde was quantitatively transferred to the aqueous phase in the form of a sodium bisulfite adduct. This shows that. 150 mmol of dicyclopentadiene was added again to the organic solvent phase containing most of the solvent and substantially free of the generated aldehyde, and a hydroformylation reaction was carried out under the same conditions as the first time. Analysis of the mixture obtained after the reaction revealed that dicyclopentadiene was 100% converted, and 108 mmol of diformyltricyclodecane and 40 mmol of formyltricyclodecene were produced. Example 2 In an electromagnetic induction stirring autoclave with an internal volume of 200ml
HRh (CO) (PPh ₃ ) ₃ 1.0m mol/, PPh ₃ 30m
mol/and 1,7-octadiene 2.0mol/
After charging 110 ml of a toluene solution containing gaseous phase and removing it by displacement, a mixed gas of H ₂ /CO = 1/1 was supplied to 50 Kg/cm ² G, and the reaction was carried out at 100°C for 1.5 hours. Ivy. Rapid gas absorption is observed from around 80℃, but by constantly replenishing the mixed gas of H ₂ /CO = 1/1 during the reaction, the pressure inside the autoclave can be adjusted to between 60Kg/cm ² G and 70Kg/cm ² G. I kept it in between. From the analysis results of the contents after the reaction, 1,7-octadiene was not detected, and C ₁₀ -dialdehyde 196m
It was found that 16 mmol of molC ₉ -monoaldehyde was contained. A sodium bisulfite aqueous solution obtained by dissolving 80 g of sodium bisulfite in 500 ml of water was added to the above reaction mixture, and stirring was started in a nitrogen atmosphere.
A temperature increase was observed from ℃ to 40℃. After returning to room temperature, 400 ml of water was added and stirred, and the upper and lower layers were separated. When the upper organic solvent layer was analyzed, it was found that only a trace amount of C ₉ -monoaldehyde remained. Almost no ₁₀ -dialdehyde was detected. Add 1,7-octadiene to this organic solvent phase again.
180 mmol and 30 ml of toluene were added, and the reaction was carried out for 4 hours under the same conditions as the first time. From the analysis results of the mixture obtained after the reaction, C ₁₀ −
150 m mol dialdehyde, _C9 -monoaldehyde
It was found that 21 mmol was produced. Example 3 The present invention was carried out using 1,5-cyclooctadiene as the raw diolefin. Inner volume 200ml
HRh(CO) in an electromagnetic induction stirring autoclave
After charging 120 ml of a benzene solution containing 1.3 mmol of (PPh ₃ ) ₃ , 50 mmol of PPh ₃ and 2.2 mol of 1,5-cyclooctadiene and removing the air in the gas phase by displacement, H ₂ /CO= A 1/1 mixed gas was supplied up to 50 kg/cm ² G, and the reaction was carried out by holding at 100° C. for 1.4 hours. Rapid gas absorption is seen from around 75℃, but by replenishing the mixed gas of H ₂ /CO = 1/1, the pressure inside the autoclave can be reduced to 60℃.
Kg/cm ² G and 70 Kg/cm ² G. Almost no 1,5-cyclooctadiene was found in the contents after the reaction, and formylcyclooctene
34m mol, diformylcyclooctane 227m
It contained mol. The reaction mixture was transferred to a 500 ml flask equipped with a stirrer and a thermometer, and an aqueous sodium bisulfite solution containing 60 g of sodium bisulfite dissolved in 250 ml of water was added. When stirring was started under a nitrogen atmosphere, an addition reaction of sodium bisulfite to the generated aldehyde occurred, and the temperature rose from 25°C to 43°C. When the mixture was cooled to room temperature and separated into an upper layer and a lower layer, and the benzene phase in the upper layer was analyzed, it was found that only a very small amount of formylcyclooctene was observed, and that most of the aldehyde produced had migrated to the aqueous phase. When 230 mmol of 1,5-cyclooctadiene and 30 ml of benzene were added again to the above benzene phase and the reaction was carried out under the same conditions as the first time, 1,5-
It was found that 100% of cyclooctadiene had reacted, and 48 mmol of formylcyclooctene and 171 mmol of diformylcyclooctane were produced. Example 4 In this example, in order to prove that the activity of the rhodium-triarylphosphine-based complex according to the present invention persists in recycled use, 5-vinyl-2-norbornene was used as the raw diolefin, and the catalyst was used repeatedly. I went there. In an electromagnetic induction stirring autoclave with an internal volume of 200ml.
HRh (CO) (PPh ₃ ) ₃ 2.0m mol/, PPh ₃ 100m
mol/and 5-vinyl-2-norbornene
Prepare 110ml of toluene solution containing 2.3mol/
After air replacement, 70kg/H ₂ /CO = 1/1 mixed gas
The reaction was carried out by feeding up to cm ² G and keeping the temperature at 100° C. for 1.5 hours. The pressure inside the autoclave is H ₂ /
By replenishing CO=1/1 mixed gas, 75
Kg/cm ² G and 85 Kg/cm ² G. After the reaction is complete, the contents are transferred to a 500 ml flask equipped with a thermometer and a stirrer, and added with sodium bisulfite.
An aqueous sodium bisulfite solution obtained by dissolving 60 g in 250 ml of water was added, and the addition reaction was carried out in a nitrogen atmosphere. To the toluene phase separated by the above method, 5
-250 mmol of vinyl-2-norbornene and 30 ml of toluene were added and the reaction was repeated. Thereafter, the catalyst solution was separated and reused repeatedly in the same manner.
Table 1 shows the amount (m mol) of dialdehyde and monoaldehyde produced in each batch.

【table】

[Table] Example 5 5 obtained by Diels-Ander reaction of cyclopentadiene and acrolein as raw materials
The present invention was carried out using -formyl-2-norbornene. In an electromagnetic induction stirring autoclave with an internal volume of 200ml.
HRh (CO) (PPh ₃ ) ₃ 1.0m mol/, PPh ₃ 50m
Pour 130 ml of toluene solution containing 2.1 mol/mol of 5-formyl-2-norbornene, and after replacing with air, add 50 ml of a mixed gas of H ₂ /CO = 0.8/1.
After supplying up to Kg/cm ² G, raise the temperature to 100℃,
The reaction was carried out. The pressure inside the autoclave was 50Kg/cm ² G during the reaction.
It was maintained between 60Kg/cm ² G. The contents after the reaction include the raw material 5-formyl-2
-Almost no norbornene was observed, and analysis revealed that 265 mmol of diformylbicycloheptane was produced. The contents were mixed with a thermometer and a stirrer.
Transfer to a 500ml flask and add 60g of sodium bisulfite.
An aqueous solution obtained by dissolving in 300 ml of water was added, and an addition reaction was carried out under a nitrogen atmosphere. At the same time as stirring started, the temperature rose from 20°C to 35°C, indicating that the addition reaction was progressing. The toluene solution in the upper layer and the aqueous solution in the lower layer were separated. No diformylbicycloheptane was observed in the toluene solution, indicating that the adduct was completely extracted into the aqueous solution. In a toluene solution containing the catalyst thus obtained, 5-
Add 200 m mol of formyl-2-norbornene again.
In addition, when the reaction was carried out under the same conditions as described above, 190 mmol of diformylbicycloheptane was obtained.

Claims (1)

[Scope of Claims] 1. Non-conjugated diolefins having 6 or more carbon atoms or non-conjugated unsaturated aldehydes having 7 or more carbon atoms are treated with hydrogen in the presence of a rhodium complex catalyst in an organic solvent that is immiscible with water. In the method of producing dialdehydes by hydroformylation by reacting with carbon monoxide, after the hydroformylation reaction is completed, the reaction solution is brought into contact with an aqueous aqueous bisulfite aqueous solution to remove the formed aldehydes, including dialdehydes, from an alkali bisulfite aqueous solution. The organic solvent phase containing the catalyst and the aqueous phase containing the alkali bisulfite adduct of the produced aldehyde, mainly dialdehyde, are separated and recovered by extraction in the form of an adduct into an aqueous solution. A method for producing dialdehydes. 2. Claim 1, wherein the non-conjugated diolefins are bridged alicyclic diolefins that have a bridgehead carbon in the molecule and two olefinic double bonds are present on both sides of the bridgehead carbon. The method described in section. 3. The non-conjugated unsaturated aldehydes are bridged alicyclic unsaturated aldehydes that have a bridgehead carbon in the molecule, and an olefinic double bond and a formyl group are present on opposite sides of the bridgehead carbon. , the method according to claim 1. 4. The method according to claim 1, wherein the rhodium complex catalyst is a rhodium triarylphosphine complex catalyst. 5. The method according to claim 1, wherein the alkali bisulfite is sodium bisulfite.