JPS5921851B2 - Production method of alkyl carboxylic acid ester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing alkyl carboxylic acid esters, particularly for producing alkyl carboxylic acid esters from carbon monoxide, alcohol, and halogenated alkyl compounds. Concerning the production method of esters.

Hitherto, various methods for producing alkyl carboxylic acid esters have been proposed; for example, Japanese Patent Publication No. 40-10967
As described in the above issue, there is a method in which carbon monoxide, a halogenated alkyl compound, and an alcohol are reacted under basic conditions using a cobalt tetracarbonyl salt as a catalyst and an inorganic base or an organic nitrogen base.

However, this method uses sodium salt of cobalt tetracarbonyl obtained by reacting dicobalt octacarbonyl in the presence of sodium amalgam in a nitrogen stream as a catalyst, and reacts carbon monoxide, alcohol, and... However, the yield is low and
The amount of catalyst used was several tens of times the number of moles of raw materials, and the method for producing the catalyst was impractical, leaving many problems to be solved for industrial use. The present invention aims to solve these problems, and by reacting a cobalt compound, carbon monoxide, and hydrogen in an alcohol solvent, it is possible to perform a one-step reaction without using dicobalt octacarbonyl or sodium amalgam. By producing an alcoholic solution of cobalt tetracarbonyl anion and using this as a catalyst, and selecting the reaction conditions and basic substance, the catalytic activity can be further increased to about 0.05 to 0.1 mole per mole of raw material. is sufficient to produce an alkyl carboxylic acid ester in high yield.

That is, the present invention improves the production method of a cobalt tetracarbonyl catalyst that has only a low catalytic activity in this type of reaction, thereby obtaining a cobalt tetracarbonyl anion with significantly improved catalytic activity and stability. , we have successfully provided a method for producing alkyl carboxylic acid esters in high yield by reacting them under pressure.

The present invention will be explained in more detail below.

First, the halogenated alkyl compound used in the method of the present invention is represented by the general formula R-X, where R is an alkyl group having 1 to 8 carbon atoms, an alkoxyalkyl group, a cyanoalkyl group, an amylalkyl group, substituted alkyl groups, such as
It represents unsaturated aliphatic groups such as methacryl group, butenyl group, pentenyl group, and acryloxymethyl group, and alicyclic groups such as cyclopentyl group, cyclohexyl group, and vinylcyclohexyl group.

Further, X is a halogen, and represents a halogen bonded to the carbon of the aliphatic group or alicyclic group of R.

Specific examples of halogenated alkyl compounds suitable for the purpose of the present invention include the following compounds, but the present invention is not limited thereto.

Methyl chloride, methylene chloride, ethyl chloride, ethyl bromide, ethylene dichloride, butyl chloride, amyl chloride, 3-chloropropane, pentyl bromide, amyl iodide, octyl iodide, 2-iodooctane, oleyl chloride, stearyl bromide, dichlorobutane, Dibromobutane, chlorinated kerosene, acryl chloride, acryl bromide, crotyl chloride, crotyl fluoride, methallyl chloride, pentenyl chloride, pentenyl iodide, undecenyl chloride, dichlorobenzene, 3-chloropropionitrile, chloroacetonitrile , 3-bromobutyronitrile, β-chloroethyl ethyl ether, β-medichlorodiethyl ether, chloromethyl isobutyl ether, β-bromoethyl vinyl ether, α-chloropropylpropyl ether, cyclohexyl chloride, cyclopentyl bromide, tetrahydrofurfuryl chloride , chloroacetone, diethyl 4-chlorobutyraldehyde acetal, and the like.

The catalyst used in the present invention is a cobalt tetracarbonyl anion, which has high activity and the reaction proceeds satisfactorily even with a small amount of catalyst.

Furthermore, most of the counter ions of the cobalt tetracarbonyl anion used in the present invention are hydrogen cations, and although it can be assumed that a small amount of cobalt cations are present, there are no side reactions at all.

The catalyst used in the present invention is obtained by reacting a cobalt compound, carbon monoxide, and hydrogen in alcohol, but the conditions are slightly milder than those for producing dicobalt octacarbonyl (for example, 160°C, 200kg/
Cr! l) The resulting homogeneous solution of alcohol can be used as it is, which is industrially superior.

A common cobalt compound as used in the present invention is an inorganic compound such as cobalt hydroxide or a cobalt salt, and excludes carbonyl compounds.

The alcohol used in the present invention is not particularly limited as long as it is an aliphatic alcohol, and examples thereof include methanol, ethanol, isopropanol, and n-butanol.

It is also preferable to use the same alcohol as the catalyst solution used.

Furthermore, in addition to alcohol, inert solvents such as aliphatic saturated hydrocarbons, aromatic hydrocarbons, pyridine, picoline, and alcohol esters of organic acids may be coexisting.

The molar ratio of the catalyst and the rogogenated alkyl compound is 1:
The ratio is 4 to 1:100, preferably 1:5 to 1:50.

The basic substance has the role of capturing hydrogen halide produced as a by-product in the reaction, and therefore, it can be anything that reacts with mono-hydrogen halide, but sodium carbonate, ammonia, etc. It is desirable that the material be highly dispersible and easy to handle.

The reaction temperature is 30-100°C, preferably 40-70°C.
It is.

The reaction pressure is 2 to 50 kg/Cd, preferably 5 to 50 kg/Cd.
It is 30 kg/Cd. The carbon monoxide used does not need to be of particularly high purity, and even if hydrogen and inert gas are used together, the yield will not decrease. In the method of the present invention, when the base used is a compound that easily reacts with the raw material halogenated alkyl compound, such as alcoholade, ammonia, or caustic soda, the base is added in small portions to carry out the reaction.

When using other bases, there are no restrictions on the method of charging, and an alcoholic solution of cobalt tetracarbonyl may be added in portions to the halogenated alkyl compound, basic substance, and alcohol solution, or cobalt tetracarbonyl anion A rogenated alkyl compound may be added in portions to the alcohol solution, basic substance, and alcohol.
Furthermore, even if all the raw materials are charged at once and the reaction is carried out, there is little change in yield. As explained above, the present invention involves the production of an alkyl carboxylic acid ester from carbon monoxide, alcohol, and a non-rogenated alkyl compound.
The catalyst is cobalt tetracarbonyl anion, which is industrially advantageous because it is in the form of a solution and is easy to handle.It also has high catalytic activity and no by-products, resulting in a high yield. This is an excellent method for producing alkyl carboxylic acid esters.

Reference Example: Method for producing an alcoholic solution of cobalt tetracarbonyl anion A 0.5f.
of methanol and 0.5 mol of cobalt hydroxide are charged.

The reactor was heated with a mixed gas of carbon monoxide and hydrogen (molar ratio 10:
After replacing the air in the reactor in step 3), the mixed gas is pressurized and heating and stirring are started. Internal temperature 160℃, pressure 2
Boost the voltage to 00k9/Cd.

After that, the pressure starts to drop, and when it drops to 20 kg/Cd, it increases again to 200 k9/Cd. This method was repeated, and after confirming that there was no drop in pressure after about 7 hours, the reaction was stopped. When the reaction solution was transferred to another glass pressure-resistant container, no precipitate was observed, and a homogeneous solution was obtained.

This solution was analyzed using infrared absorption spectroscopy, titration, atomic absorption, and iodine decomposition method, which is an analytical method for dicobalt octacarbonyl and cobalt tetracarbonyl anions [Anal.
Chem. Volume 24 rot 1, January 1952, 174-176
Page], and the methylene blue titration method, which is an analytical method for cobalt tetracarbonyl anion [Bull. Chem.
SOc. JAPan Volume 35. 462, 1962 247
-251 pages], it was confirmed that all the cobalt carbonyls in the reaction solution were CO(CO)4-.

Example 1 1517 1-prom-normal pentane, 0.5 mol of soda carbonate, and 300 cc of methanol were charged into a 11-sized pressure-resistant reactor equipped with a stirrer, and after replacing the air with carbon monoxide, heating and stirring were started, and the temperature was raised to 50 ml. 10k9/C at °C
d, methanol solution 12 of cobalt tetracarbonyl anion produced in the same manner as in the reference example.
5CC (containing CO(CO)4127) is added by pump within 5 hours.

Simultaneously with the start of the fractional addition, the reaction was carried out while continuously purging the gas at a rate of 30 cc/Mi, and the mixture was aged for 1 hour after the fractional addition.
After the reaction, the reaction solution was taken out, made acidic with sulfuric acid, and analyzed by gas chromatography. As a result, caproic acid methyl ester 857 (yield 65%) was produced. Example 2
~6...A reaction was carried out in substantially the same manner as in Example 1 using the compounds shown in Table 1 as the rogogenated alkyl compounds.

However, in the case of Example 3, a basic solution was added in portions instead of the catalyst solution, and in the case of Example 4, a halogenated alkyl compound was added in portions. Furthermore, since the basic substance was not soda carbonate, there was no need to continuously purge the gas in Examples 3 and 4. The reaction conditions and yields are summarized in Table 1.

[Brief explanation of the drawing]

FIG. 1 is an infrared absorption spectrum diagram of a catalyst used in an example of the present invention.

Claims (1)

[Scope of Claims] 1 A halogenated alkyl compound represented by the general formula and, in some cases, have a double bond, an ether group, a nitrile group, or a carbonyl group in its carbon chain, or a halogen bonded to the terminal carbon) with carbon monoxide and an alcohol. To produce an alkyl carboxylic acid ester, an alcoholic solution of a cobalt tetracarbonyl anion obtained by reacting an ordinary cobalt compound under pressure in an alcohol solvent in an atmosphere of carbon monoxide and hydrogen is used as a catalyst, and a basic A method for producing alkyl carboxylic acid esters by reacting under pressure in the presence of a substance.