JPS59231036A - Synthesis of acetaldehyde - Google Patents

Abstract

PURPOSE:To produce acetaldehyde, by forming a complex of Cu(1) and oxygen and a complex of Pd(2) and ethylene in a solution, and oxidizing ethylene at low temperature and pressure. CONSTITUTION:A solution containing Cu(1).trisdimethylaminophosphine oxide complex and Pd(2).acetonitrile complex is made to contact with an oxygen-containing gas in the oxygen absorption tower 1 to obtain a solution containing an oxygen complex [L.Cu(1).O2]. Ethylene is oxidized to acetaldehyde by introducing the solution into the reactor 2 and contacting with an ethylene-containing gas introduced through the line 21. The oxygen complex solution is decomposed into the original complex catalyst and a solution containing acetaldehyde and unreacted ethylene by the process, and the components are separated from each other by the distillation column 3 and the degassing column 4. The unreacted ethylene and the complex catalyst solution are circulated to the system through the line 61 and the line 51, respectively, and the objective acetaldehyde is extracted through the line 71.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for synthesizing acetaldehyde, and particularly to a method for synthesizing acetaldehyde by oxidizing ethylene.

The basic chemicals that serve as starting materials for petrochemical products include acetaldehyde, acetic acid, and ethylene glycol (or ethylene oxide), and how to synthesize these at low temperatures and low pressures is a leading goal in technological development. Among these, aldehydes represented by acetaldehyde (hereinafter referred to as CH3CHO) are used in the chemical industry as raw materials for acetic acid synthesis by the acetaldehyde method, ethyl acetate synthesis by the Tfsch-enko reaction, or penquetathritol synthesis by the Celanese method. It occupies an important position in

The industrially practiced synthesis method for CH3CHO is (1)
The ethanol dehydrogenation method and (2) ethylene oxidation method (Hoechst method, Wallaker method) are roughly divided into two, but the former requires a high cost of ethanol as a raw material (and a high temperature (260°C)).
The latter Hoechst method (19
(1959) and the Wanker method (1960) have become mainstream, and currently a large amount of 500,000 tons of acetaldehyde is synthesized every year.

This ethylene oxidation method oxidizes ethylene made from naphtha using a catalyst that combines cupric chloride (hereinafter referred to as Cu(2)ICl) and palladium chloride.
In the method of obtaining HO, the overall reaction is shown by equation (1). This general reaction formula is said to be established from three reaction formulas (2) to (4).

2 Cu(1)C1+ 2 HCl +-0,-1→2
Cu C12+ HzO(4) That is, first divalent palladium (P d (2)C1
Ethylene and water coordinate to 2), and ethylene is carbonylated, but at this time, Pd(2)CI2 is replaced by metal (Pd (0
)). Since (Pd (0)) does not exhibit catalytic activity, it is oxidized by divalent copper (Cu (2) Clz) and returned to (P d (2) C12).

In this case, Cu (21C12 is monovalent copper (Cu(13C1
), this is oxidized with oxygen according to equation (4) to form Cu (2) Cli. The Wanker method uses such Pd (21CI, and Pd (0) and Cu (
2) The oxidation/reduction reaction between C12 and Cu(IIcI) is skillfully utilized to synthesize acetopredehyde through the carbonylation reaction of ethylene. However, P d
(The coordination force of ethylene to the 21CI2 complex is not strong, or Cu (1) Cu of CI (2) C1
Due to the rapid rate of oxygen oxidation reaction to 2, the reaction is carried out under conditions of a pressure of IQ atm or higher and a temperature of around 100°C, and an increase in equipment cost and operating cost cannot be avoided. Therefore, There is a desire to develop a method for synthesizing acetaldehyde from ethylene at lower temperatures and pressures.

The present invention eliminates the drawbacks of the prior art described above and provides a method for synthesizing acetaldehyde by oxidizing ethylene under reaction conditions of lower temperature and lower pressure.

The present inventors have discovered that a complex solution of a -valent copper compound (trisdimethylphosphine oxyto complex solution) is a -carbon oxide (CO
), and applied for a patent; however, upon further investigation, it was discovered that this complex was excellent as an absorbent for CO and oxygen (
In the presence of 02), we surprisingly found that CO was oxidized in the liquid phase at a low temperature by the 02 complex, and furthermore, we applied this complex to the production of acetaldehyde by ethylene oxidation method. As a result of intensive research, we have arrived at the present invention.

The present invention is characterized in that a complex of monovalent copper and oxygen (M complex) and a complex of divalent palladium and ethylene (ethylene complex) are formed in a solution to oxidize ethylene.

More typically, the present invention provides a complex (hereinafter referred to as L C
u (denoted as 11) and a complex consisting of divalent palladium and nitriles (hereinafter, L'・P d (denoted as 21)
The process is characterized by the synthesis of acetaldehyde by oxidizing ethylene with oxygen at low pressure and low temperature using the catalyst as a catalyst.

In the present invention, in order to form a complex between -valent copper and oxygen, a -valent copper compound dissolved in a coordinating solvent such as HMPA is brought into contact with an oxygen-containing gas, such as air. good. In addition, the complex of divalent palladium and ethylene is
It is obtained by allowing ethylene to act on a complex of a divalent palladium compound and a nitrile.

The synthesis reaction of the present invention is as shown in formula (5), L-
Oxygen complex of Cu (1) (hereinafter referred to as L-Cu (11・0□) and ethylene complex of L′・P d (2) (hereinafter referred to as
It is thought that L'-Pd (denoted as 21CH2=CH3) reacts.

2L-Pd(2)-CH2=CH2+ CL-Cu(x
)) 202→2 CH2OHO+ 2 L' ・P d
(2) +2 L-Cu (1) (5) In the present invention, Cu (11) which provides -valent copper may include cuprous bromide, cuprous iodide, cuprous sulfate, etc. However, cuprous chloride is particularly preferred from the viewpoint of price and solubility of the complex with HMPA.Also, as the divalent palladium compound, palladium acetate, palladium sulfate, palladium nitrate, etc., or nitrile Palladium chloride is particularly preferred from the viewpoint of the equilibrium constant of complex formation with compounds and the solubility of the complex.Furthermore, as the nitriles, aliphatic nitriles such as acetonitrile and propionitrile, aromatic nitriles such as benzonitrile and tolnitrile, etc. can be given.

In addition, solvents for dissolving L-Cu (1) and L'P d (21) include aromatic hydrocarbons such as xylene, alcohols such as butanol, ethers such as butyl ether and butyl cellosolve, and esters such as butyl acetate. Ketones such as methyl isobutyl ketone, ketones such as dimethylpolamide, amides such as dimethylformamide, sulfoxides such as dimethyl sulfoxide, glycols such as ethylene glycol,
Examples include at least one compound selected from carbonates such as propylene carbonate, but HMP
A, nitriles, and mixed solvents of both can also be used. Among these solvents, HMPA and acetonitrile are preferred because of their large boiling point difference with the acetaldehyde produced, ease of separation, and their ability to dissolve complexes.
Particularly preferred are mixed solvents of HMPA and benzonitrile.

L-Cu(1) and L'-P d (
A solution containing Cu(2) is prepared by adding a Cu(1) compound to HMPA to form a liquid L-Cuil) complex, and then separately adding a Pd(2) compound to a nitrile to form L′・P.
d (After forming 21, HMA can be produced by mixing the two and diluting with a solvent, but Cu (
11 compounds, HMPA, and Pd (it is also possible to prepare by simultaneously mixing the 21 compounds and nitriles. The concentration of L-Cu (1) in the above solution is 0.1% per solution 1β.
The range is preferably from 0.05 to 5 mol, particularly preferably 0.1
~5 moles. Also, the concentration of L'・Pd(2) is 0.0
The range of 0.05 to 0.1 mol is preferred. In either case.

If it is too low, the reaction will not proceed, and if it is too high (then C
Precipitation of compound u (1) or p d (21 compound occurs and is not effective.

In the present invention, in order to form an oxygen complex of the L-Cu(1) complex, an oxygen-containing gas may be brought into contact with the L-Cu(1) complex (for example, by blowing into the complex). As the oxygen source, oxygen gas, air, or a compound that generates oxygen or an oxygen-containing gas can be used, but from an economical point of view, it is generally preferable to use air. The oxygen-containing gas is L-Cu
(Not only the 11 complex, but also the L-Cu(1) complex and L'
- P d 12) It may be blown into a mixed solution of the complex.

In the present invention, the molar ratio of the oxygen complex of L-Cu (1) to ethylene in the liquid is preferably 1:2 (stoichiometric ratio) or more. When an oxygen complex exists in excess of ethylene, C
Oxygen oxidation of u (1) to Cu t21 occurs gradually, which may lead to deterioration of the catalyst in the long term.

The complex solution of the present invention may contain stabilizers such as surfactants and antioxidants to improve dispersibility, and co-catalysts to further enhance the catalytic effect.

In the present invention, if the reaction temperature is too low, the oxidation rate of ethylene becomes slow, which is undesirable. On the other hand, if the reaction temperature is too high, monovalent copper (Cu (1)) is converted into divalent copper (Cu (2)) as an interfering reaction. ) and the elimination reaction of ethylene from the ethylene complex, which is not preferable.

Generally, a range of 20°C to 80°C is suitable, but the temperature is not limited to this range.

The concentration of ethylene complex in the liquid is higher when the reaction pressure is increased.
That is, it is preferable because the concentration of activated ethylene is high, but the nitrile complex of divalent palladium used in the present invention has a stronger activation power of ethylene than the chloro complex of palladium chloride used in the Wanker method, etc. Normal pressure is also sufficient.

When ethylene is oxidized in the complex solution according to the present invention, CH3CHO1L'・P d
(21, L-Cu (11, and unreacted L-Pd (
2) A mixed solution such as C=C is obtained. Acetaldehyde can be separated by distilling this solution using the difference in boiling points, for example. In the process of the present invention, oxygen is quantitatively and irreversibly coordinated to the Cu(11.HMPA complex), and the reaction can be carried out without the presence of oxygen in the gas phase, so there is no risk of mixed explosion. It is very safe.

Next, an apparatus for carrying out the method of the present invention will be explained with reference to FIG. This apparatus includes an oxygen absorption tower (spray tower) 1 that brings the complex solution according to the present invention into contact with an oxygen-containing gas to form a catalyst solution containing the aforementioned oxygen complex, and an oxygen absorption tower (spray tower) 1 that contacts the complex solution according to the present invention with an oxygen-containing gas to form a catalyst solution containing the above-mentioned oxygen complex. A reactor 2 in which ethylene is introduced and oxidized by the catalyst solution to produce acetaldehyde, a distillation column 3 which distills the reaction solution to separate acetaldehyde and unreacted ethylene from the catalyst solution, and acetaldehyde and ethylene. It mainly consists of a degassing tower 4 for separation. In the figure, 11 is an oxygen-containing gas line, 21 is an ethylene-containing waste line, 31 is an oxygen complex solution line, 41 is an acetaldehyde solution line, and 51 is an oxygen-containing gas line.
61 is an unreacted ethylene gas line, 71 is an acetaldehyde gas line, and 81 is an exhaust gas line.

In the apparatus having the above configuration, the catalyst solution containing the Cu (11.HMPA complex and the P d (2).acetonitrile (RCN) complex) is brought into contact with the oxygen-containing gas in the oxygen absorption tower 1, and is mixed with the solution containing the aforementioned oxygen complex. This solution is fed into reactor 2 and oxidizes ethylene to acetaldehyde according to equation (5).At this time, the oxygen complex solution is a solution containing the original complex catalyst, acetaldehyde, and unreacted ethylene. This solution is separated into ethylene, acetaldehyde, and a complex catalyst solution in a distillation column 3 and a degassing column 4. The acetaldehyde is returned to the absorption tower 1 for circulation and use, and acetaldehyde is obtained as a product from the bottom line 71 of the degassing tower 4.

In the above apparatus, acetaldehyde can be synthesized by introducing ethylene into the absorption tower 1 (or by omitting the absorption tower 1 and simultaneously absorbing ethylene and oxygen in the reactor 2.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 Cuprous chloride (hereinafter referred to as CuC1) 0.05 g (0.5 mmol) and HMP were placed in a 10 mI2 reaction tube.
Prepare 3.3g (18 mmol) of A, Cu (11C
3.3 mβ of 1-HMPA complex solution was prepared. Furthermore, palladium chloride (hereinafter referred to as Pd) was added to another 10 mA reaction tube.
C12,,! 0.013 g (0.07 mmol) and acetonitrile (CH3CN) 1.3
g (32 mmol) and Pd(1)C12.
1.7 ml of (CH3CN)2 complex solution was prepared. After that, both were mixed and 0.1 m was obtained as C11 (1) C1.
o l/j! , Pd (0.015m as 21C12
o I/j! (7) 5 ml of catalyst 1'8 liquid was prepared. 8 ml of air was bubbled through this at 25°C under normal pressure.
3 m It (0,06i 'J mol) of 02 is absorbed and 0. Complex ((L -Cu (
11) 202) Concentration 0.012mol/j! A solution of was obtained. Thereafter, nitrogen gas was passed through the reaction tube, but only the 02 remaining in the gas phase in the reaction tube was removed, and no desorption of 02 from the 02 complex in the liquid was observed.

After this operation, ethylene was added at 25°C under normal pressure for 5
0 m I! When aerated, 18 mA of ethylene was absorbed, and the ethylene concentration in the liquid was 0.16 m2.

It became 1/β. Then, immediately warm it to 60℃, and
After reacting for a minute, the reaction solution was cooled. When the product was analyzed by gas chromatography, 0.096 mmol of CH3CHO was produced.

The reaction between the ethylene complex and the 0□ complex follows the above-mentioned formula (5), and in this example, the ethylene complex is present in excess with respect to the q complex. Therefore, in this example, CH2
The conversion rate to OHO was 80% based on the 02 complex concentration.

Example 2 A reaction was carried out in the same manner as in Example 1 except that the reaction temperature was 40°C and 90°C for 30 minutes. As a result, CH3
The yield of CHo is 0. 3 at 40℃ based on complex concentration
2%, and 51% at 90°C. In particular, at 90°C, it was observed that ethylene was desorbed into the gas phase of the reactor, and some Cu (11) in the liquid was oxidized to Cu (2), losing catalytic activity. This was recognized.

Example 3 By changing the aeration amount, 0. Complex concentration (A) 0.0
12mo+/#, (B) 0.023mo! ,/jl
! , (C) 0.043mol/j! Other than that, the relationship between the reaction time and the C 2 H 2 OHO yield (based on the C 2 complex concentration) was determined in the same manner as in Example 1.

The results are shown in Figure 1 (in the figure, A, B, and C indicate the cases of each of the above C2 complex concentrations), and it was observed that the yield was higher when the Ot isomer concentration was lower at the same reaction time. Ta.

This means that if the concentration of O2 complex is too high, Cu in the solution
This is thought to be because (1) is oxidized to CLl (2).

Example 4 The reaction was carried out in the same manner as in Example 1 except that acetonitrile was replaced with benzonitrile. As a result, the yield of CH2OHO was 98%, which was higher than that of acetonitrile.

Example 5 Cu Cl 1P d C12, HMPA and CH3
CN, 10mj! was charged into a reaction tube to prepare 5 ml of a catalyst solution having the same composition as in Example 1. In addition, Example 1
By the same operation as 0. When 02 and ethylene were bubbled through the solution, the composition of 02 and ethylene in the solution was the same as in Example 1. When this was reacted for 30 minutes at 60°C, the same as in Example 1, the yield of CH2OHO was 7 on the O7 complex basis.
It was 9%, and no significant difference from Example 1 was observed.

Comparative Example 1 In Examples 1 and 2, a catalyst solution having the same composition was prepared except that PdCl2 was not added, and the same operation as in Example 1 was performed. As a result, CH2OHO was not produced.

Furthermore, in Examples 1 and 2, CuC1 was not added,
A catalyst solution having the same composition was otherwise prepared, and the same operation as in Example 1 was performed.

As a result, no formation of CH2OHO was observed in this case as well. From the above, it was found that at least CuC1 and PdC,1, need to be present in the catalyst liquid according to the present invention.

Comparative Example 2 In Examples 1.4 and 5, nitriles were not added, catalyst solutions having the same composition were otherwise prepared, and the same operations as in Example 1 were performed. As a result, CH3CHO was not produced. From this result, it was recognized that 2l-zyl group is also essential. This is considered to be because nitriles greatly contribute to the activation of the palladium-ethylene complex.

As described above, according to the present invention, acetaldehyde can be synthesized by oxidizing ethylene at a lower temperature and lower pressure than conventional methods. The method of the present invention is also more advantageous than the conventional method in terms of operability and economy.

[Brief explanation of the drawing]

Figure 1 shows the reaction time and CH2O in Examples of the present invention.
FIG. 2, a diagram showing the relationship between HO yields, is a diagram showing an apparatus system for carrying out the method of the present invention. ■...Absorption tower, 2...Reactor, 3...Distillation column, 4
...Degassing tower, 11...0. Contained gas line, 21
...Ethylene-containing gas line, 31...026it
Body solution line, 41...Acetaldehyde solution line. Representative Patent Attorney Takenaga Kawakita Figure 1 Figure 2 1 Procedural Amendment 1980, i'', o 28th of May Director General of the Patent Office Kazuo Wakasugi Indication of Case 14 1989 Patent Application No. 04291 No. 2, Title of the invention Method for synthesizing acetaldehyde 3, Relationship with the case of the person making the amendment Patent applicant 4, Agent 103 Address 11-8-6, Kayabacho-Chome, Nihonbashi, Chuo-ku, Tokyo
, Subject of amendment: Claims section and Detailed Description of the Invention section of the specification. 7. Contents of the amendment (1) The scope of claims is amended as shown in the attached sheet. (2) "Trisdimethylbosphine oxide" in lines 5-6 and last line of page 5 of the specification is changed to "trisdimethylaminephosphine oxide J." A method for synthesizing acetaldehyde, which comprises forming a complex of copper and oxygen (oxygen complex) and a complex of divalent palladium and ethylene (ethylene complex), and oxidizing ethylene. The method for synthesizing acetaldehyde according to item 1, wherein the oxygen complex is formed by introducing an oxygen-containing gas into a complex of -valent copper and trisdimethylaminobosphine oxide. (3) In claim 1 or 2, M
ij A method for synthesizing aldehydes, characterized in that the ethylene complex is formed by introducing ethylene into a complex of divalent palladium and a nitrile. (4) A method for synthesizing acetaldehyde according to any one of claims 1 to 3, characterized in that the molar ratio of the ethylene complex to the oxygen complex is 2 or more.

Claims (1)

[Claims] (1) A complex of monovalent copper and oxygen (oxygen' complex) and a complex of divalent palladium and ethylene (ethylene complex) are formed in a solution to oxidize ethylene. A method for synthesizing acetaldehyde characterized by the following. (2. Claim 1 is characterized in that the oxygen complex is formed by introducing oxygen-containing + into a complex of -valent copper and trisdimethylphosphine oxide. A method for synthesizing acetaldehyde, characterized in that the acetalbutylene complex is formed by introducing ethylene into a complex of divalent palladium and a nitrile. (4) Items 1 to 3 above. A method for synthesizing acetaldehyde, wherein the molar ratio of the ethylene complex to the oxygen complex is 2 or more.