JPS6324501B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a new method for producing 7-octenoic acid, and more specifically to 2,7-octadiene-1-
isomerizes ol in the presence of a catalyst to produce 7-
The present invention relates to a method for producing 7-octenoic acid, which comprises oxidizing octene-1-al with oxygen in the presence of an oxidation catalyst in a liquid phase. 7-Octenoic acid is a compound useful as a raw material for 8-aminocaprylic acid, as a modifier for vinyl polymers, and as a starting material for various organic syntheses, but its industrial production method is particularly unknown. The current situation is that this is not the case. Previously, the present inventors discovered that 2,7-octadien-1-ol can be industrially advantageously produced by reacting butadiene and water in the presence of a palladium complex catalyst (Unexamined Japanese Patent Publication No. (Refer to Publication No. 138129, 1983). Against this background, the present inventors have conducted intensive studies on methods for synthesizing various useful derivatives using 2,7-octadien-1-ol as a starting material. As a result, 2,7-octadien-1-ol is isomerized in the presence of a catalyst selected from the group consisting of a copper-based catalyst and a chromium-based catalyst, and the generated 7-octene-1-al is isomerized in the presence of an oxidation catalyst. When oxygen oxidizes in the liquid phase, 7
-Discovered that octenoic acid was produced in high yield,
The present invention has now been completed. This method has advantages that are suitable for industrial implementation, such as easy availability of starting materials and simple steps. 2,7-octadiene according to the method of the present invention
Copper-based catalysts and chromium-based catalysts used as catalysts in the isomerization reaction of 1-ol include reduced copper, Raney copper, copper zinc oxide, copper chromium oxide,
Examples include zinc chromium oxide.
The metal oxide catalysts mentioned above are commercially produced and can be easily obtained. It can also be manufactured according to the method described in the publication (published by Jinshokan). The above literature describes, for example, a method for producing copper chromium oxide, in which chromium trioxide is added to powdered or paste copper oxide, an appropriate amount of water is added thereto, the mixture is mixed and crushed for several hours, and then dried. ing. These catalysts may be partially modified with other metal components selected from tungsten, molybdenum, rhenium, zirconium, manganese, titanium, iron, barium, and the like. Further, a catalyst supported on a carrier such as alumina, silica, diatomaceous earth, etc. can also be used. These catalysts may be used alone or in combination of two or more. Catalyst activity may be improved if the catalyst is previously treated with hydrogen prior to use. When the reaction is carried out in the liquid phase, the catalyst has a concentration of 0.1 to 0.1 to the reaction mixture in terms of metal.
It is used in a proportion of 20% by weight. The isomerization of 2,7-octadien-1-ol is performed while the catalyst is partially poisoned by coexisting appropriate amounts of sulfur compounds, antimony compounds, bismuth compounds, phosphorus compounds, nitrogen compounds, etc. in the reaction system. The selectivity of 7-octene-1-al may be improved by carrying out the reaction. The sulfur compounds include sulfur and sodium sulfate, the antimony compounds include antimony oxide, the bismuth compounds include bismuth oxide, the phosphorus compounds include phosphoric acid and triphenylphosphine, and the nitrogen compounds include pyridine, Examples include aniline and the like. In addition, when the isomerization reaction of 2,7-octadien-1-ol is carried out using a general-purpose palladium catalyst, nickel catalyst, cobalt catalyst, rhodium catalyst, platinum catalyst, etc. as an isomerization and hydrogenation catalyst,
The production of 7-octene-1-R is small, and 7-
Since many by-products are produced in large quantities that are virtually impossible to separate from octene-1-al, these general-purpose catalysts are -Cannot be used in reaction to produce R. 2,7-octadiene according to the method of the present invention
The isomerization reaction of 1-ol is preferably performed using nitrogen gas,
The reaction is carried out in an atmosphere of an inert gas under reaction conditions such as carbon dioxide gas, helium gas, argon gas, etc., but part or all of the inert gas may be replaced with hydrogen gas. However, when the reaction is carried out in the presence of hydrogen gas, it is better to keep the partial pressure of hydrogen gas at 10 atmospheres or less. If the partial pressure of hydrogen gas exceeds 10 atmospheres, the rate of hydrogenation reaction will increase and the selectivity of 7-octen-1-al will decrease, which is not preferable. The reaction temperature is selected from the range of 100 to 250°C, particularly 130 to 220°C. The reaction can be carried out in a stirred reactor, a bubble column reactor or a packed column reactor in the liquid or gas phase in continuous or batch mode. When the reaction is carried out in a liquid phase, the raw material 2,7-octadien-1-ol or the product 7-octen-1-al can also function as a solvent. This reaction can also be carried out using other organic solvents that are inert under the reaction conditions. Usable organic solvents include saturated aliphatic hydrocarbons such as hexane, octane, decane, and liquid paraffin, saturated alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, benzene, toluene, xylene,
Aromatic hydrocarbons such as biphenyl, ethers such as diisopropyl ether, dibutyl ether, dioctyl ether, diphenyl ether, tetrahydrofuran, diethylene glycol diethyl ether, polyethylene glycol dimethyl ether, ethanol, butanol, octanol, ethylene glycol, glycerin, polyethylene glycol, etc. alcohols, etc. 7-octene-1 produced by the method of the present invention
-R is the reaction raw material 2,7-octadiene-1
-Since it has a lower boiling point than 7-octene-
Conducting the reaction while distilling 1-R out of the reaction system (reactive distillation method) is one of the particularly desirable embodiments of the method of the present invention, and this further suppresses the production of by-products. In addition, it is also possible to carry out the reaction in the gas phase or liquid phase while continuously flowing 2,7-octadien-1-ol in a reactor filled with a shaped isomerization catalyst for a short contact time. -1- This is effective in increasing the selection rate of R. 7-octene-1-al produced in the reaction can be separated and obtained from the reaction mixture or distillate by a conventional distillation operation. 7-octen-1-al is converted to 7-octenoic acid by contacting it with an oxygen-containing gas in the presence of an oxidation catalyst and an organic solvent. As the oxygen-containing gas, oxygen gas, air, a mixed gas of nitrogen and oxygen in an arbitrary ratio, or a mixed gas of these and carbon dioxide gas is used. The reaction pressure varies depending on the amount of oxygen contained in the oxygen-containing gas, so it cannot be determined unambiguously, but generally it is 1.
Selected from within the range of ~15 absolute atmospheres. As an oxidation catalyst, cobalt salt, manganese salt, nickel salt,
Metal salts known per se as aldehyde oxidation catalysts, such as copper salts and iron salts, can be used. Aliphatic monocarboxylic acid salts are preferable as metal salts in consideration of solubility in the reaction mixture, corrosiveness to the reaction equipment, and ease of availability. In consideration of solubility in the mixed liquid, copper or iron aliphatic monocarboxylate is particularly preferred as the oxidation catalyst. These oxidation catalysts may be used alone or in combination of two or more. The oxidation catalyst is generally a reaction mixture 1
It is used at a ratio of 0.01 to 50 mmol per.
Examples of organic solvents that can be used in the oxidation reaction according to the present invention include aliphatic monocarboxylic acids and esters thereof, but aliphatic monocarboxylic acids are preferred in consideration of catalyst solubility and stability. Specific examples of aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, etc., and specific examples of aliphatic monocarboxylic acid esters include the above-mentioned aliphatic monocarboxylic acids. Examples include methyl ester, ethyl ester, n-propyl ester, isopropyl ester, n-butyl ester, isobutyl ester, and n-pentyl ester. The reaction temperature is generally in the range of about 40 to about 120°C, but preferably 60 to 80°C when a copper salt and/or iron salt is used as the oxidation catalyst. Further, when a cobalt salt, manganese salt or nickel salt is used as an oxidation catalyst, the reaction temperature is preferably 40 to 60°C. The oxygen oxidation reaction of 7-octen-1-al according to the method of the present invention is carried out by continuously or intermittently supplying an oxygen-containing gas and 7-octen-1-al to a reaction solvent in which an oxidation catalyst is dissolved. Implemented. In this case, by adjusting the supply rate of 7-octen-1-R so that the concentration of 7-octen-1-R in the reaction mixture is maintained at 0.50 mol/or less, the accumulation of reaction heat is suppressed, and the -Octene-1-al and 7-octenoic acid polymerization and side reactions such as decarboxylation are prevented, and the selectivity of the reaction is further improved. In addition, 7- in the reaction mixture
It is also effective to always maintain the concentration of octenoic acid at about 3 mol/less or less in order to prevent polymerization of the product 7-octenoic acid and to improve the selectivity of the reaction. As the reaction apparatus, a stirred reaction tank or a bubble column type reaction tank is preferably used. After the oxidation catalyst is removed from the reaction mixture by a known method, 7-octenoic acid can be separated and obtained in good yield by distillation. The method of the present invention will be specifically explained below using Examples. Example 1 1 Production of 7-octene-1-al 2,7-octadien-1-ol (purity:
99.9% or more) and 2.0 g of powdered copper chromium oxide catalyst (manufactured by JGC Chemical Co., Ltd., N-203) were charged, and the flask was immersed in an oil bath maintained at 205°C. With vigorous stirring, 2,7-octadien-1-ol was continuously fed at a rate of 170 ml/hr using a metering feed pump while nitrogen gas was passed at a rate of 30/hr. The isomerization (distillation) reaction of 2,7-octadien-1-ol was carried out in this manner for a total of 8 hours. Approximately 170 ml of distillate was obtained per hour, and the liquid volume in the flask was maintained at approximately 30 ml throughout the reaction. 8
A total of 1350 ml of distillate was obtained by the reaction for hours. Analysis by gas chromatography revealed that the distillate contained 16.9 mol% of unreacted 2,7-octadien-1-ol and n-octylaldehyde.
2.7 mol%, n-octanol and octene-1-
Total of ols: 8.9 mol%, 7-octene-1
- It was found that 70.7 mol% of R was contained. When 1.0 kg of the distillate thus obtained was purified using a glass distillation column with 40 theoretical plates,
7-octene-1- as a fraction at 58℃/10mmHg
Approximately 700 g of R (purity 98%, containing approximately 2% n-octylaldehyde) was obtained. 2 Production of 7-octenoic acid 30 ml of propionic acid, ferrous acetate 32 in a 100 ml four-necked flask equipped with a thermometer, stirrer, reflux condenser, raw material feed port, and oxygen gas inlet.
mg (3.0 mmol per reaction mixture) and the contents were warmed with stirring to completely dissolve the ferrous acetate. A microfeeder connected to the raw material feed port was charged with 50 ml of a 4 mol/7-octen-1-al propionic acid solution that had been purged with nitrogen gas. When the temperature inside the reactor became constant at 65℃, the contents were poured out.
Stir at a rotational speed of 800 rpm, and add oxygen gas to 10
/hr while introducing 7-octene-1 at a feed rate of 10ml/hr from the raw material feed port.
-R's propionic acid solution was continuously added over 3 hours to carry out an oxidation reaction. After the addition of 7-octene-1-R was completed, stirring was continued for an additional 2 hours at the same temperature. The internal temperature was kept constant at 65°C during the reaction period. At the end of the oxidation reaction (5 hours after the start of the reaction), the conversion rate of 7-octene-1-al was 88%, and the selectivity to 7-octenoic acid (based on conversion 7-octene-1-al) was 85%. It was hot. Analysis of the reaction product by gas chromatography revealed small amounts of by-products such as heptene and formic acid. Further, off-gas analysis conducted every hour from the start of the reaction revealed that the carbon dioxide generation rate (based on converted 7-octene-1-R) was 3.5 mol%. After washing the reaction mixture obtained above with 60 ml of 1N aqueous hydrochloric acid, the organic layer was distilled under reduced pressure to obtain 10 g of 7-octenoic acid as a fraction at 98-99°C/2 mmHg. Reactions similar to those in 1) above were carried out for 1 hour using various catalysts instead of copper chromium oxide. Table 1 shows the selectivity of 7-octene-1-al contained in the distillate.

[Table] Examples 2 to 7 7-octene-1- obtained in 1) of Example 1
The type and amount of the catalyst, the type of solvent, and the amount for the feed were determined in the same manner as in 2) of Example 1.
Oxidation was carried out by varying the concentration of -octene-1-R, oxygen-containing gas, reaction temperature, and reaction time as shown in Table 2. The results are summarized in Table 2.

【table】

Claims (1)

[Claims] 1 7-octene- produced by isomerizing 2,7-octadien-1-ol in the presence of a catalyst selected from the group consisting of a copper-based catalyst and a chromium-based catalyst.
A method for producing 7-octenoic acid, which comprises oxidizing 1-R with oxygen in a liquid phase in the presence of an oxidation catalyst.