JPH0350739B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to 2-(4-hydroxyphenoxy)
The present invention relates to a method for producing propionic acid ester. The 2-(4-hydroxyphenoxy)propionic acid ester obtained by this invention is an important compound as a raw material for agricultural chemicals. The compound is usually combined with hydroquinone under basic conditions.
-It is obtained by reacting with a halopropionate ester, but this method involves the reaction of both of the two hydroxyl groups of hydroquinone with the 2-halopropionate ester, or a side reaction in which the ester bond is hydrolyzed. The desired 2-(4-hydroxyphenoxy)propionic acid ester could only be obtained in a low yield. Japanese Unexamined Patent Publication 1973-
Publication No. 19925 describes hydroquinone as hydroquinone 1.
A process is described for reacting with chloroacetic acid ester in the presence of 2 mol to mol of alkali metal alkoxide. However, in this method, 2 moles of alkali metal alkoxide, which is an expensive reagent, must be used per 1 mole of hydroquinone, and it cannot be said to be an economical method. Further, West German Patent Publication No. 3150233 describes that ethyl 2-(4-hydroxyphenoxy)propionate can be obtained by reacting hydroquinone and 2-bromopropionate in the presence of calcium hydroxide. However, when the reaction is carried out using hydroquinone and 2-chloropropionic acid ester, which is cheaper than 2-bromopropionic acid ester, in the presence of calcium hydroxide according to this method, the reactivity is extremely low; (4-hydroxyphenoxy)
It is difficult to obtain propionate esters in high yields. In view of these current circumstances, the present inventor has determined that 2-(4-
As a result of extensive research aimed at developing an industrial production method that can advantageously produce hydroxyphenoxy)propionic acid ester, we found that in the presence of a solvent that azeotropes hydroquinone and an alkali metal hydroxide. After removing water, the target product 2-(4-
The inventors have discovered that hydroxyphenoxy)propionic acid ester can be obtained in high yield and that the above objects can be achieved, leading to the present invention. The present invention provides a method for producing 2-(4-hydroxyphenoxy)propionate by reacting hydroquinone with 2-halopropionate, in which hydroquinone is reacted with an alkali metal in the presence of a solvent that is azeotropic with water. The present invention relates to a method for producing a 2-(4-hydroxyphenoxy)propionic ester, which comprises reacting with a hydroxide to remove water and then reacting with a 2-halopropionic ester in the presence of an alcohol. The 2-halopropionic acid ester used in the present invention has the formula CH ₃ CHXCOOR ... [] (wherein, X represents Cl or Br, and R represents a C ₁ to C ₄ linear or branched alkyl group) ). Representative examples of 2-halopropionic acid esters represented by formula [] include 2
-methyl chloropropionate, ethyl 2-chloropropionate, n-propyl 2-chloropropionate, i-propyl 2-chloropropionate, 2
-n-butyl chloropropionate, i-butyl 2-chloropropionate, s-butyl 2-chloropropionate, methyl 2-bromopropionate,
Ethyl 2-bromopropionate, n-propyl 2-bromopropionate, i-propyl 2-bromopropionate, n-butyl 2-bromopropionate, i-butyl 2-bromopropionate, s-2-bromopropionate Butyl, t-butyl 2-bromopropionate, and the like can be mentioned. The amount of these 2-halopropionate esters used is
0.5 to 2.0 mol per 1 mol of hydroquinone, especially 0.6
~1.3 mol is preferred. Further, examples of the alkali metal hydroxide used in the present invention include sodium hydroxide, potassium hydroxide, and lithium hydroxide, and these may be used in any form such as solid, aqueous solution, or alcoholic solution. The amount of alkali metal hydroxide used is preferably 1.0 to 2.2 mol, particularly 1.5 to 2.0 mol, per 1 mol of hydroquinone. Solvents that are azeotropic with water in the present invention include aromatic hydrocarbons such as benzene, toluene or xylene, saturated hydrocarbons such as pentane, hexane, cyclohexane or octane, ethanol, 1-propanol, 2-propanol, 1
Mention may be made of alcohols such as butanol, 2-butanol or isobutanol, and ketones such as ethyl methyl ketone, cyclopentanone, cyclohexanone or methyl isobutyl ketone, which may also be used in appropriate combinations. . The amount of solvent is not particularly limited as long as it is at least the amount theoretically necessary to remove existing water. The reaction between hydroquinone and an alkali metal hydroxide is usually carried out under pressure at a temperature above the azeotropic temperature with water, or may be carried out under reduced pressure at a temperature below this temperature. In the present invention, the alcohol used when reacting the reaction product of hydroquinone and alkali metal hydroxide with 2-halopropionic acid ester includes:
It is preferable to use the same alcohol as the ester moiety of the 2-halopropionic acid ester. In addition, when carrying out the reaction with 2-halopropionic acid ester in the presence of an alcohol, it is necessary that the azeotropic solvent used in the reaction between hydroquinone and the alkali metal hydroxide is the same alcohol as the ester moiety. or in the case of a mixed solvent with the above-mentioned alcohol, 2-
It can be reacted with halopropionic acid esters. If the azeotropic solvent is a solvent other than alcohol, the solvent can be removed by an appropriate method such as distillation, and then the same alcohol as the ester part is added, or the same alcohol as the ester part can be added without removing the solvent. can be reacted with a 2-halopropionic acid ester. The amount of alcohol is preferably 2 to 20 parts by weight per 1 part by weight of hydroquinone used. The reaction temperature and time with the 2-halopropionic acid ester are suitably 0 to 150°C and 0.5 to 10 hours. After the reaction is complete, the reaction solution is made neutral to slightly acidic with an organic acid such as acetic acid or propionic acid, or a mineral acid such as hydrochloric acid, sulfuric acid, sulfuric acid, or phosphoric acid, and then processed using a conventional method such as distillation. It can be obtained by isolation operation. EXAMPLES The present invention will be explained in more detail by way of Examples below. The reaction solution was quantified by gas chromatography analysis. Hydroquinone reaction rate, 2-
The yield and selectivity of (4-hydroxyphenoxy)propionic acid ester are in accordance with the following definitions. Reaction rate of hydroquinone (%) = number of moles of consumed hydroquinone/number of moles of charged hydroquinone x 100 Yield of 2-(4-hydroxyphenoxy)-propionate (%) = 2-(4-hydroxyphenoxy)-propionate produced Number of moles of (enoxy)-propionate ester/Number of moles of charged hydroquinone x 100 Selectivity of 2-(4-hydroxyphenoxy)propionate (%) = Produced 2-(4-hydroxyphenoxy) -Number of moles of propionate ester/Number of moles of consumed hydroquinone×
100 Example 1 11.0 g of hydroquinone, 16.7 g of a 48% by weight aqueous sodium hydroxide solution and 100 ml of toluene were placed in a flask with a Dean-Stark trap and heated under a nitrogen atmosphere, and the reaction was stirred for 3 hours until water no longer azeotroped. (12.2 ml of water was separated).
Remove the trap and remove toluene under reduced pressure.
100 ml of absolute ethanol was added to the residue, which was then heated to 30° C. with vigorous stirring, and 13.7 g of ethyl 2-chloropropionate was added at once. After reacting for 3 hours, 8 ml of glacial acetic acid was added to stop the reaction.
As a result, the reaction rate of hydroquinone was 78%, and 2
The amount of ethyl -(4-hydroxyphenoxy)propionate produced was 15.1 g (yield and selectivity were 72% and 92%). Example 2 The same procedure as in Example 1 was carried out except that the reaction of ethyl 2-chloropropionate was carried out at 15° C. for 4 hours. As a result, the reaction rate of hydroquinone was 62%, and 2-
The amount of (4-hydroxyphenoxy)propionic acid ester produced was 12.4 g (yield and selectivity were 59% and 95%). Examples 3 and 4 The same procedure as in Example 1 was carried out, except that the solvents listed in Table 1 were used in place of toluene in Example 1, and the mixture was heated and stirred until water no longer azeotroped. The results are shown in Table 1.

[Table] Example 5 Hydroquinone 4.29g and sodium hydroxide 3.12g
were reacted in 50 ml of toluene by heating to about 100° C., and the azeotropic water was separated in the same manner as in Example 1. Water separation was carried out over a period of about 3 hours. After cooling, remove toluene under reduced pressure and add 30% absolute ethanol.
Added ml. The resulting suspension was heated to 30°C and 2-
Add 4.11g of ethyl chloropropionate all at once;
After reacting for 3 hours, the same post-treatment as in Example 1 was performed. As a result, the reaction rate of hydroquinone was 67%, and the amount of 2-(4-hydroxyphenoxy)propionic acid ester produced was 5.0 g (yield and selectivity were 61% and 91%). Example 6 3.3 g of hydroquinone and 2.4 g of sodium hydroxide were heated and reacted in 50 ml of 1-butanol, and the resulting water was removed by azeotropy with 1-butanol over 2.5 hours. After cooling, 4.9 g of butyl 2-chloropropionate was added and reacted at 25° C. for 4 hours, followed by the same post-treatment as in Example 1. As a result, the reaction rate of hydroquinone was 85%, and the amount of butyl 2-(4-hydroxyphenoxy)propionate produced was
5.6 g (yield and selectivity 78% and 92%).

Claims (1)

[Claims] 1 Hydroquinone and the formula [1] CH ₃ CHXCOOR ... [] (wherein, X represents Cl or Br, and R represents a C ₁ to C ₄ linear or branched alkyl group) 2-halopropionic acid ester represented by
- In a method for producing (4-hydroxyphenoxy)propionate, hydroquinone is reacted with an alkali metal hydroxide in the presence of a solvent azeotropic with water to remove water, and then in the presence of an alcohol. 2, characterized in that it is reacted with a 2-halopropionic acid ester represented by the above formula [].
- A method for producing (4-hydroxyphenoxy)propionic acid ester.