JPS636053B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for efficiently producing a carbonyl compound from an alcohol having 5 carbon atoms, and more specifically, a method for efficiently producing a carbonyl compound by using a high boiling point carboxylic acid ester solvent. Regarding the method. A method for obtaining a corresponding carbonyl compound by oxidizing a primary alcohol or a secondary alcohol having 3 to 7 carbon atoms using a ruthenium-based oxidizing agent is known (for example, JP-A-52-39611, JACS, 80) . ,
6682 (1958), Canadian J.Chem., 50 , 3741
(1972), Tetrahedron Letters, No. 47, 4729
(1967)). However, in such conventional techniques, in many cases, the reaction is carried out by adding the alcohol to be oxidized to carbon tetrachloride as a solvent, or the reaction is carried out without using a solvent at all. RuO ₄ which already has oxidizing power when using an agent,
Carbon tetrachloride is often used as a convenient solvent for stably preserving Na ₂ RuO ₄ after forming it into a form such as Na 2 RuO 4 . Furthermore, when using a catalytic amount of a ruthenium-based oxidizing agent and an oxidizing agent such as sodium hypochlorite, solvents that are oxidized by the oxidizing agent such as sodium hypochlorite cannot be used, and therefore solvent-free systems cannot be used. Perform the reaction or JCS, Perkin I,
According to the description in 1974, 222, saturated hydrocarbons such as n-octane, dodecane, and cyclohexane can be used. However, all of these methods proposed in the prior art are unsatisfactory as actual industrial synthesis methods. For example, carbon tetrachloride is inert to sodium hypochlorite, and RuO ₄
Regarding the distribution of
Although it has the advantage of having a large retention force for RuO ₄ ,
Generally has a lower boiling point compared to the desired product;
When separating the solvent from the product, it is necessary to distill off a large amount of the solvent, so it cannot be said to be a practical solvent. Moreover, when no solvent is used, the target product undergoes a secondary oxidation reaction, resulting in a decrease in reaction selectivity. For example, a ketone may be formed from a secondary alcohol, followed by a halofolum reaction with an oxidizing agent such as sodium hypochlorite. Furthermore, when a saturated hydrocarbon is used as a solvent, the following drawbacks are observed. That is, according to UAspitzer et al. (JOC40, 2539 (1975)), cyclopentane, cyclohexane, cycloheptane, and cyclooctane are converted into cyclopentanone and glutaric acid, and cyclohexanone and adipic acid, respectively, in the presence of RuO ₄ and sodium hypochlorite. It is reported that these cycloparaffins are oxidized to cyclopentanone and pimelic acid, and cyclooctanone and suberic acid, and these cycloparaffins cannot be said to be stable solvents.On the other hand, paraffins such as octane and dodecane are generally oxidized to alcohols. It has poor compatibility and is insufficient to play its primary role as a solvent. Therefore, the present inventors conducted intensive studies to improve this drawback of the conventional technology, and as a result, the high-boiling point carboxylic acid ester solvent is sufficiently effective against oxidizing agents such as ruthenium-based oxidizing agents and sodium hypochlorite. They found that it is stable, easy to separate from the target product, and suitable from the standpoint of practical production efficiency, and have completed the present invention. That is, an object of the present invention is to provide a method for efficiently producing a highly pure carbonyl compound, and an object of the present invention is to prepare a primary or secondary alcohol having 5 carbon atoms at a boiling point of 150°C or higher. After oxidizing to a carbonyl compound using a ruthenium-based oxidation catalyst and a co-oxidizing agent in the presence of a carboxylic acid ester solvent, the reaction product is distilled to remove the carbonyl compound as a low-boiling component. achieved. The alcohol subjected to the reaction in the present invention is a primary or secondary alcohol having 5 carbon atoms,
Specific examples include n-pentanol and cyclopentanol. In the present invention, the corresponding carbonyl compounds (i.e., valeraldehyde and n-valeric acid from n-pentanol, and cyclopentanone from cyclopentanol) are obtained by oxidizing such alcohols with a ruthenium-based oxidation catalyst. . The ruthenium-based oxidation catalyst used in this reaction may be any commonly used oxidation catalyst, including ruthenium tetroxide, ruthenates (sodium ruthenate, potassium ruthenate, etc.), and perruthenates. (sodium perruthenate, potassium perruthenate, etc.). Further, in the present invention, a co-oxidizing agent is used in combination in order to reuse the ruthenium-based oxidation catalyst that becomes deactivated as the reaction progresses. This co-oxidant may be any one that can oxidize low-valent ruthenium compounds with no oxidizing power, such as ruthenium dioxide and ruthenium trichloride, to a ruthenium-based oxidation catalyst. Specifically, hypochlorous acid Examples include sodium, sodium chlorate, sodium peroxyate, sodium periodate, chlorine, potassium permanganate, and peracetic acid. Among these, sodium hypochlorite is preferred due to its ease of operation and economic efficiency. The amount of the ruthenium-based oxidation catalyst and co-oxidant to be used may be appropriately selected depending on the desired product and optimum yield, but usually the former is 0.1 molar equivalent or less, preferably 0.1 molar equivalent or less, based on the alcohol to be oxidized. 0.001〜
0.03 molar equivalent is suitable, the latter being 0.2 to 5 times the stoichiometric amount required for the reaction, preferably 0.5 to 2.5
It's double the amount. In addition, the method of adding the ruthenium-based oxidation catalyst and co-oxidant may be selected as appropriate; specifically, a method in which the required amount of the former is charged in advance and then the latter is added sequentially, or a method in which both are added sequentially is preferred. Ru. In the present invention, a high-boiling carboxylic acid ester solvent (an ester composed of a saturated aliphatic carboxylic acid and a saturated aliphatic or saturated alicyclic alcohol) having a boiling point of 150°C or higher, preferably 160°C or higher is used in the reaction. Ru. Specific examples of such solvents include 2-ethylbutyl acetate, 2-ethyl acetate,
Ethylhexyl, isoamyl propionate, n-butyl butyrate, isoamyl butyrate, isoamyl isovalerate, n-amyl valerate, amyl lactate,
Examples include cyclopentyl acetate, cyclohexyl acetate, and methylcyclohexyl acetate. These solvents are as stable as carbon tetrachloride, which has traditionally been used in this reaction, and are superior in compatibility with alcohols and stability compared to hydrocarbon solvents. There is.
Furthermore, since the solvent used in the present invention has a higher boiling point than the target product, the product can be distilled out as a low-boiling component when separating the product by distillation, which is compared to the conventional method using a low-boiling point solvent. A product of high purity can be obtained efficiently compared to the conventional method. In particular, when n-pentanol is present as the raw alcohol, it is preferable to use n-amyl valerate as the solvent, and in this case, n-amyl valerate by-produced during the reaction is removed. This not only eliminates the need for it, but also has the advantage that process losses of solvent can be replaced by the by-product. In the present invention, the reaction is carried out according to a conventional method except for using the specific solvent. For example, the amount of solvent used is usually at least the same amount, preferably 1.2 to 10 times the amount of alcohol to be oxidized,
The larger the amount used, the better the selectivity of the desired product, but the larger the reaction apparatus and solvent recovery apparatus become, making it impractical, so the optimum amount to be used is appropriately selected. The reaction is usually carried out under normal pressure or increased pressure.
The reaction time is 0.1 to 5 hours at a temperature of .degree. C., but these conditions are not particularly limiting. In the present invention, after the reaction is completed, the target carbonyl compound is separated as a low-boiling component by distilling the reaction product according to a conventional method. The method and conditions for distillation are not particularly limited, but usually, taking into account the thermal stability of the product, the boiling point of the solvent, etc., it is carried out under reduced pressure, normal pressure, or increased pressure, preferably at a pressure of 10 mmHg absolute pressure to 5 atm. Distillation can be carried out by selecting the reflux ratio as appropriate, and preferably by adopting a value of 0.5 to 20, taking into consideration the specific volatility of the components, desired purity, recovery rate, etc. The type of apparatus may be either a batch type or a continuous type, and may be a packed column or a tray column. The present invention will be explained in more detail with reference to Examples below. Example 1 N-valeric acid was added to a glass reactor equipped with a stirrer.
After charging 100 parts by weight of n-amyl (boiling point 204°C) and 13 parts by weight of cyclopentanol, 0.26 parts by weight of ruthenium dioxide dihydrate (RuO ₂ 2H2O) (0.01 mol per 1 mol of cyclopentanol) was added in advance. equivalent)
After adding 161 parts by weight of a sodium hypochlorite aqueous solution with an effective chlorine concentration of 10% (equivalent to 1.5 mol per 1 mol of cyclopentanol) at normal pressure and room temperature (25~
(29°C) over 2 hours. After the reaction, the organic phase was separated from the aqueous phase using a batch distillation column with an inner diameter of 30 mm, a packed bed length of 1.5 m, and a McMahon packing packing, under reduced pressure (160 mmHg absolute pressure) and a reflux ratio of 4 to 5. Distilled. Distillate A (top distillation temperature
60-84℃) is 1.69 parts by weight (cyclopentanone purity
99.74%), 9.13 parts by weight of distillate B (distillation temperature 85°C) (cyclopentanone purity 99.9%), 0.94 parts by weight of distillate C (distillation temperature 90-150°C) (contains cyclopentanone) rate of 18.3%). The temperature of the can liquid gradually increased from the initial 130°C to 155°C. Cyclopentanone obtained from distillates A and B is
The amount recovered was equivalent to 82.1 moles for 100 moles of cyclopentanol charged before the reaction. In addition,
The reaction results were a cyclopentanol conversion rate of 99.7% and a cyclopentanone selectivity of 88.9%. Comparative Example 1 When the reaction conditions of Example 1 were repeated except that the solvent was changed to cyclohexane (boiling point 80.7°C), the reaction results for cyclopentanone production were almost the same, but the cyclohexane was not reacted. Cyclohexanone, which was thought to have been produced, was detected (the amount produced was equivalent to 2.6 mol per 100 mol of cyclohexane), and the rate of disappearance of cyclohexane reached 11.4% of the charged amount. Comparative Example 2 When the same reaction as in Example 1 was carried out without using a solvent, the cyclopentanone yield was 55% (selectivity 78.6%) at a cyclopentanol conversion rate of 70%, and the cyclopentanone conversion rate was 95%. With a cyclopentanone yield of 54% (selectivity 56.8%) and a cyclopentanol conversion rate of 100%, the cyclopentanol yield was 44% (selectivity 44%), and as the conversion rate increased, the selectivity decreased rapidly. Example 2 100 parts by weight of n-amyl valerate, 12 parts by weight of n-pentanol, and ruthenium dioxide dihydrate (n
- 0.0083 mol per 1 mol of pentanol) was charged into a glass reactor, and the mixture was heated to room temperature (25 to 29 mol) while stirring.
As a result of dropwise addition of an aqueous sodium hypochlorite solution (an amount equivalent to 1.25 mol of sodium hypochlorite per 1 mol of n-pentanol) over a period of 2 hours at ℃), the conversion rate of n-pentanol was 80%, and the barrel An aldehyde yield of 49% was obtained. After the reaction, the organic phase was separated and distilled using the same batch distillation apparatus as in Example 1 under reduced pressure (300 mmHg absolute pressure) at a reflux ratio of 4.0 to give 29% by weight of n-pentanol and 70% of valeraldehyde. A distillate containing 1% boiling content (corresponding to 6.9 parts by weight per 100 weight of charged organic phase) was obtained. In order to remove unreacted n-pentanol from this distillate, it was further distilled using a batch distillation apparatus under the conditions of a reflux ratio of 3.0 and reduced pressure (150 mmHg absolute pressure), and 96% pure valeraldehyde was obtained. . Example 3 According to Example 1, a reaction was carried out using cyclopentyl acetate as the solvent and cyclopentanol as the alcohol to be oxidized, and the cyclopentanone yield was 100% with a cyclopentanol conversion rate of 100%.
A reaction result of 91.2% was obtained. Next, this was carried out in Example 1.
Distilled in accordance with
Got it with 89%.

Claims (1)

[Claims] 1. Oxidation of a primary or secondary alcohol having 5 carbon atoms into a carbonyl compound using a ruthenium-based oxidation catalyst and a co-oxidizing agent in the presence of a carboxylic acid ester solvent with a boiling point of 150°C or higher. 1. A method for producing a carbonyl compound, which comprises distilling the reaction product and distilling the produced carbonyl compound as a low-boiling component. 2 Alcohol is cyclopentanol or n-
The manufacturing method according to claim 1, which is pentanol.