JPS61194038A - Production of cycloalkanol or cycloalkanone - Google Patents

Abstract

PURPOSE:To obtain the titled substance economically, in improved selectivity of the cycloalkane conversion, by carrying out the liquid-phase oxidation of a cycloalkane compound with an O2-containing gas in the presence of a boron compound and in the copresence of formic acid or a formic acid salt. CONSTITUTION:A cycloalkane compound (usually 3-12-membered compound, e.g. cyclopropane, methylcyclopentane, etc., especially preferably cyclohexane) is oxidized with an O2-containing gas in liquid phase in the presence of a boron compound. The above reaction is carried out by adding formic acid or a formic acid salt to the oxidation reaction system in an amount of preferably >=10ppm, especially 200-5,000ppm in terms of formic acid based on the cycloalkane compound used as the raw material, usually at 100-250 deg.C, especially at 150-180 deg.C under an inert gas (e.g. N2) pressure of preferably about 5-25kg/cm<2> G to obtain the titled compound.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing compounds or cycloalkanones.

[Conventional technology]

Cycloalkanols that are compatible with a method of liquid phase oxidation of cycloalkanes with a molecular oxygen-containing gas in the presence of a catalyst or a boron f-arsenide.

This method is highly selective to cycloalkanones and is widely practiced.

[Problem that the invention seeks to solve]

However, in these methods, when attempting to increase the conversion rate of cycloalkanes, undesirable phenomena occur from an economical or operational standpoint, such as a significant decrease in selection straw and an increase in the formation of Harz.

Therefore, various co-catalysts, additives, etc. have been proposed in order to normally set the conversion rate of cycloalkanes to about 3 to 1/θ and to improve the total selectivity of cycloalkanol [-cycloacicanone]. In either case, the effects were insufficient.

[Means for solving problems]

In view of the above circumstances, the present inventors have developed a method of liquid phase oxidation of cycloalkanes in the presence of a boron compound in order to further improve the selectivity by adding formic acid or a formate salt into the reaction system together with the boron compound. The present invention was achieved by discovering that the selectivity of cycloalkanols or cycloalkanones can be greatly improved.The present invention will be described in detail below.

The cycloalkanes used as raw materials in the present invention are usually
, 3-/co-membered ring, and may have a branched chain.

These specific gif+ include cyclopropane, cyclobutane, cyclopentane, cyclohexane, cyclooctane, cyclododecane, methylcyclopentane, methylcyclohexane, dimethylcyclohexane, decahydronaphthalene, tetralin, cyclohexylbenzene,
Examples of the boron compound present in the oxidation reaction yarn include dicyclohexylhexane, and cyclohexane is particularly preferred. The boron compound present in the oxidation reaction thread is usually at least one selected from boric acids and boric acid esters, such as orthoboric acid, metaboric acid, tetraboric acid, and boric anhydride. One type is used.

These boron compounds are used in an amount of /ρ mol or more as boron per mol of cycloalkanol produced by oxidation.

When the reaction is carried out batchwise, there is little problem even if the boron compound is present as a solid, so it can be used in large excess; however, when the reaction is carried out continuously, it is necessary to avoid clogging the equipment and other inconveniences. It is best to reduce the amount of solid boron compounds as much as possible, and usually OJ~ as boron per 7 moles of cycloalkanol! 'f'i is not particularly limited as an acid salt in which the molar atom range is selected, but it is best to choose from, for example, asimonium salts: salts of alkali metals such as sodium and potassium; salts of alkaline earth metals such as magnesium and calcium, etc. .

The use of gi al or formate is 10 ppm or more, preferably /θ, in terms of ρ based on the raw material cycloalkanes.
Q~110000pp, more preferably 20θ~! 0
It is preferable to add in a range of 0.00 ppm.

That is, if the amount of oxygen used is below the range of the present invention, the effect of the present invention will not be fully exhibited, and conversely, even if it is too large, the effect will not change, so it is not economical.0 Molecular oxygen used for oxidation As the gas containing , oxygen, air, or a gas obtained by diluting these with an inert gas can be used, but air is usually sufficient. It is preferable that the oxygen concentration is relatively low. 1 Normal! The temperature of the oxidation reaction using a ~co/capacity of 4 degrees is usually 7θQ-co! Preferably, iro~/rO<0>C is 1% of θ<0>C. If the temperature is too low, the oxidation reaction will not proceed, whereas if the temperature is too high, the production of by-products will increase, which is not preferable.

In addition, the reaction pressure can be either normal pressure or elevated pressure, and should be selected appropriately taking into account the vapor pressure and oxygen partial pressure at the reaction temperature of the raw cycloalkanes.
θOkg/crltG I], preferably j −2j
kg/all G is good, and it is best to pressurize with an inert gas such as nitrogen.

The process of the invention can be carried out either batchwise, semi-batchwise or continuously according to well-known operating procedures. In case of continuous operation, gas inlet pipe, gas outlet fP
While feeding a cycloalkane containing a boron compound and formic acid or its salt into a stirred tank having an overflow pipe and an overflow pipe, oxygen or an oxygen-containing gas is introduced from a gas introduction pipe so as to achieve a predetermined cycloalkane conversion rate. While controlling the internal temperature and pressure inside the tank, water produced by the reaction and unreacted cycloalkane are released from the gas outlet pipe. It is extracted along with the waste gas, and the reaction is carried out while the reaction liquid is extracted from the overflow pipe.

Since the oxidation reaction mixture obtained in the present invention contains cycloalkanol, it is usually in the form of hydroperoxide and boric acid ester.
~-2. After heat treatment at a temperature of f0℃1 then room temperature ~1
The desired product can be easily recovered by hydrolysis at a temperature of 00°C.

〔Effect of the invention〕

When dicycloalkanes are oxidized in liquid phase with a molecular oxygen-containing gas in the presence of a boron compound by the method of the present invention, is formic acid a salt thereof? If m is added, it is possible to improve the selectivity by 2 to 3% in the conversion rate of cycloalkanes such as (b), compared to the case where it is not added. For example, cycloalkanols and cycloalkanones such as cyclohexanol and cyclohexanone Considering that they are produced on an extremely large scale, their industrial value is sufficiently large.

〔Example〕

Implementation 911/ Gas inlet pipe, gas outlet pipe, raw material liquid inlet pipe, small liquid drain pipe, stirrer, and liquid volume to the inner volume with an overflow pipe at the 0t position! In the autoclave of t, cyclohexadi 6!
Prepare 0I and metaboric acid/3.0 g, 765°C, 7
The temperature and pressure were increased to 0 kg/7G.

After blowing in a mixed gas of KWI element S, O volume % 1 nitrogen gas, and opi volume %, and confirming that the oxygen concentration in the gas phase was below 1 IDA, the oxidizing gas was switched to air and the oxidizing gas was changed to 0. 6
! Blow was carried out continuously at a rate of t/min. From the raw material liquid introduction pipe, metaboric acid λ, O weight factor and formic acid! 00 ppm of cyclohexadi was continuously supplied at a rate of 6.7 g/7 min, waste gas containing water, cyclohexane, etc. was extracted from the gas outlet pipe, and the liquid phase was heated at 76°C while being extracted from the overflow pipe. After carrying out an oxidation reaction with θ#/cdG and then heat-treating the extracted reaction mixture at 7tf°C for 3G minutes, an equal amount of water to the reaction solution was added and hydrolysis was performed at 10°C for 30 minutes to form dicyclo. The production of hexanol and cyclohexanone was carried out.

The reaction system is in a steady state! The gas chromatography and liquid chromatography analysis of the time-exhausted gas phase and liquid phase revealed that the conversion of zeta-filtrated cyclohexane was ig, j%, and the total selectivity of cyclohexanol and cyclohexanone was 0.9%. 〇In the same oxidation method as in Examples 2 to Z and Comparative Examples, the concentration of formic acid added was 2.
! θ ppm and / 000 ppm, and the concentration of calcium formate converted to formic acid was 300.
Table 1 shows the results under conditions where ppm W& was added as examples, and for comparison, a similar oxidation was performed using only boric acid with 7JO added with formic acid as a comparative example.

Chapter/Table

Claims (4)

[Claims] (1) Production of cycloalkanols or cycloalkanones, which is characterized by the presence of formic acid or a formate salt in the oxidation reaction thread during liquid phase oxidation of cycloalkanes with molecular oxygen-containing gas in the presence of a boron compound. Method. (2) The method according to claim 1, wherein the amount of formic acid or formate salt present is 10 ppm or more as formic acid based on the cycloalkanes. (3) The method according to claim 1, wherein the cycloalkane is cyclohexane. (4) The method according to claim 1, wherein the amount of formic acid or formate salt present is 100 to 10,000 ppm as formic acid based on the cycloalkanes.