JPS61134349A - Production of 2-haloacrylic acid ester - Google Patents

Abstract

PURPOSE:The dehalogenation of a propionic acid ester is carried out using a specific amount of aqueous solution of an alkali metal oxide for a certain time to enable easy and high-yield production of the titled compound with industrial advantage. CONSTITUTION:25-55wt% aqueous solution of an alkali oxide such as sodium hydroxide is added to a propionate of formula I (X1, X4 are halogen; X2, X3 are H, X1, X4; R is alkyl, aryl) at a molar ratio of 1:(0.9-2.0) at 0-80 deg.C over 0.5-5.0hr continuously or intermittently to effect dehydrohalogenation to give the objective compound of formula II. EFFECT:The reaction process is easily controlled to inhibit side-reactions such as hydrolysis and saponification. Further, the hydrogen halide removed immediately reacts with the alkali metal hydroxide to form a halide and the halide dissolves in the reaction medium. Thus, troublesome operations are not needed, after reaction. USE:A starting material of agricultural chemicals and medicines, a starting material of a polymer for UV photoresist.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for producing 2-heroacrylic acid ester. More specifically, general formula (1) (However, in the formula, Xl-X4 represents a halogen atom, and X.

X3 each represents a hydrogen atom or a halogen atom. Further, R represents an alkyl group or an aryl group. ) is dehydrohalogenated in the presence of an aqueous solution of an alkali metal hydroxide to form a compound of general formula (n) (wherein X, , X, , X4 and R represent the general formula CI
) indicates the same thing. ) In the method for producing the 2-heroacrylic acid ester represented by the general formula (I), an amount of alkali corresponding to 0.9 to 2.0 mol per 1.0 mol of the propionic ester represented by the general formula (I) is used. A 25-55% by weight aqueous solution of metal hydroxide
．． The present invention relates to a method for producing a 2-no-10 acrylic acid ester represented by the general formula (II), which is characterized by adding continuously or intermittently over a period of 5 to 5.0 hours.

2-Haloacrylic acid esters are important compounds as raw materials for agricultural chemicals and medicines, and as raw materials for functional polymer compounds such as UV and electron beam-sensitive resists.

<Prior art> Conventionally, 2-haloacrylic acid esters have been produced using 2.3-
Dihalopropionic acid esters are dehydrohalogenated in the presence of acids such as sodium acetate (US Pat. No. 2.434,229), sodium carbonate (US Pat. No. 2.245.547), and chino. A method of synthesis is presented.

However, all of these conventional methods for producing 2-haloacrylic acid esters have numerous drawbacks.

Methods using weak bases such as sodium acetate and sodium carbonate as dehydrohalogenating agents have low conversion rates;
Since it requires a very long reaction time, it is not industrially satisfactory. Also, quinoline and N.

The method of using an organic base such as N-dimethylaniline as a dehydrogenating agent is expensive, and requires a complicated operation to filter out the hydrogen halide adduct of the organic base, which is produced as a by-product. This is disadvantageous.

De-removal using acids such as sulfuric acid, sulfo/acid type ion exchange resin, etc.
・The method of carrying out the hydrogen halogenide reaction is to
It has the disadvantage that loacrylic acid ester is easily polymerized. Furthermore, when an aqueous solution of an alkali metal hydroxide such as sodium hydroxide is used as a dehydrohalogenating agent, hydrolysis and saponification reactions are likely to occur, resulting in a low yield. Furthermore, in order to suppress the hydrolysis and saponification reactions of esters by using an alkali metal hydroxide as a dehydrohalogenation agent, it is necessary to perform dehydrohalogenation while minimizing the amount of water in the reaction system. It is necessary to carry out a reaction. As a result, not only is the operation complicated, but the reaction is also difficult to control and is not satisfactory as an industrial production method.

<Problems to be Solved by the Present Invention> The present inventors have discovered that even if an alkali metal hydroxide is used as a dehydrohalogenating agent, the reaction can be easily controlled and side reactions such as hydrolysis and saponification reactions can be avoided. The present invention was completed as a result of intensive research into a method for producing 2-heroacrylic acid ester in high yield while suppressing the above.

<Means for Solving the Problems> The present invention involves dehydrohalogenating the propionic acid ester represented by the general formula (1) in the presence of an aqueous solution of an alkali metal hydroxide to obtain the compound represented by the general formula (n). 2- indicated by
In the method for producing a haloacrylic acid ester, an amount of alkali metal hydroxide of 25 to 2.0 mol corresponding to 0.9 to 2.0 mol per 1.0 mol of the propionic ester represented by the general formula (I) is used. The present invention provides a method for producing a 2-haloacrylic acid ester, characterized in that a 55% by weight aqueous solution is added continuously or intermittently over a period of 0.5 to 5.0 hours.

When an aqueous solution of an alkali metal hydroxide is used as a dehydrogenation agent, the reaction proceeds quickly, but if the entire aqueous solution of an alkali metal hydroxide is added at the beginning of the reaction, it becomes difficult to control the reaction. Moreover, it was found that side reactions such as hydrolysis and saponification reactions were severe. but,
By gradually adding an aqueous solution of alkali metal hydroxide at a specific concentration, side reactions such as hydrolysis and saponification reactions are suppressed and the reactions can be easily controlled. Furthermore, the eliminated hydrogen halide immediately reacts with the alkali metal hydroxide to form the alkali metal halide, which easily dissolves in water, so after the reaction is complete, complicated operations such as separating the solid salt from door to door are not necessary. It was recognized that it has the advantage of not being

The propionic acid ester represented by the general formula (I) used in the present invention includes methyl 2,3-dichloropropionate, ethyl 2,3-dichloropropionate, 2,3-
Propyl dichloropropionate, propyl 2,3-dichloropropionate, m---butyl 2,3-dichloropropionate, butyl 2,3-dichloropropionate, 2,3-dichloropropionate 5-butyl acid, t-butyl 2,3-dichloropropionate, 2
．． Lupentyl 3-dichloropropionate, 2.3-
Dichloropropio'y$: I-hexyl, 2-cyclohexyl 3-dichloropropionate, 2-ethylhexyl 2-3-dichloropropionate, octyl-2,3-dichloropropionate, 2,3-dichloropropionic acid-↓ -Octyh, 2,3-diloloroprobionic acid phenyl, 2゜3-dichloropropionate pentachloro7enyl, 2,3-dichloropropionic acid-2,2,2
-) Lifluoroethyl, 2,2,3,3,3-pentafluoropropyl 2,3-dichloropropionate, methyl 2,3-dibromopropionate, ethyl 2,3-cyfuromopropionate, 2,3-dibromopropionic acid-luprovir, 2,3-sifuromopropionic acid-L
-propyl, rb-methyl 2,3-dibromopropionate, rubentyl 2,3-dibromopropionate,
z, 3-cyfuromopropionic acid-ro-hexyl, 2.3
-') cyclohexyl 7'lomopropionate, 2,3-
2-ethylhexyl dibromopropionate, z, 3-
-octyl dibromopropionate, 2,3-dipromop, L-octyl ropionate, phenyl 2,3-dibromopropionate, 2,3-dibromopropionate
Pentachlorophenyl, 2,2,2-trifluoroethyl 2,3-dibromopropionic acid, 21293?3,3-pentafluoro-2,3-dibromopropionic acid
-propyl, methyl 2,3.3-trichloropropionate, ethyl 2,3.3-)trichloropropionate, 2
, 3.3-trichloropropionic acid-3-'lopyl, 2
,3,3-trichloropropionic acid-seprovir, 2
, 3.3-trichloropropionic acid-louptyl,
2,3゜3-) IJ 2-ethylhexyl dichloropropionate, 2,3.3-1 phenyl dichloropropionate, methyl 2,3,3-tribromopropionate, 2
, ethyl 3.3-tribromopropionate, 2,3゜3
-Tribromopropionic acid-Luprovir, 2.3,3
-Tribromopropionic acid-Luprovir, 2,3.3
- ) IJ dibromopropionate 3-7' thyl, 2
, 3.3-tribromopropionate-2-ethylhexyl, 2,3.3-tribromoglobionate phenyl, 2,3. -methyl 3-tetrachloropropionate,
Methyl 2,3,3.3-tetrachloropropionate, 2
, 3,3,3-nato-2chloropropionate-ka-probyl, 2,3,3.3-tetrachloropropionate-louptyl, 2.3.3.3-tetrachloropropionate/phenyl acid, 2, Methyl 3,3.3-tetrabromopropionate, ethyl 2,3,3.3-tetrabromopropionate, 2,3,3.3-tetrabromopropionate-rugulovir, 2,3゜3.3- Examples include looptyl tetrabromopropionate, phenyl 2,3.3.3-tetrabromopropionate, and the like.

The alkali metal hydroxide used in the present invention is not particularly limited, but sodium hydroxide or potassium hydroxide is economically advantageous because it is industrially relatively inexpensive and easily available. Further, its usage ratio is in the range of 0.9 to 2.0 mol, preferably 1.0 to 2.0 mol, per 1.0 mol of propionic acid ester represented by general formula (I).
It is 1.5 mol. If the amount of the alkali metal hydroxide is less than 0.9 mol per 1.0 mol of the propionic acid ester represented by the general formula (I), the conversion rate decreases;
．． Using more than 0 mole is not only economically disadvantageous, but also tends to cause side reactions such as hydrolysis and saponification reactions.

The concentration of the aqueous alkali metal hydroxide solution used in the present invention is 25 to 55% by weight, preferably 30 to 50% by weight. If an aqueous alkali metal hydroxide solution with a concentration lower than 25% by weight is used, side reactions such as hydrolysis and saponification reactions are likely to occur. In addition, when using an aqueous solution of alkali metal hydroxide with a concentration higher than 55% by weight, heating is required to prevent the precipitation of alkali metal hydroxide crystals and maintain the aqueous solution state. It is disadvantageous because

In the present invention, the addition of the aqueous solution of alkali metal hydroxide used as a dehydrohalogenating agent is 0.5 to 5.0
Continuously or intermittently over time. An example of a method of adding intermittently is a method of adding 1/3 to -0 part by weight of the aqueous solution of the alkali metal hydroxide to be added. If the addition time is shorter than 0.5 hours, the reaction temperature will rise sharply, making it difficult to control the reaction and making side reactions such as hydrolysis and saponification reactions more likely to occur. Even if the addition time is longer than 5 hours, it is only economically disadvantageous.

Under the conditions for carrying out the present invention, the reaction temperature is 0 to 80°C, preferably 0 to 60°C. At temperatures lower than 0°C, the reaction rate decreases, and at temperatures higher than 80°C, side reactions such as hydrolysis and saponification reactions tend to occur.
It is also unfavorable because the haloacrylic acid ester is likely to polymerize.

Effects of the Present Invention According to the method of the present invention, since an aqueous solution of an alkali metal hydroxide is used as a dehydrohalogenation agent, the reaction proceeds rapidly. Further, the eliminated hydrogen halide immediately reacts with the alkali metal hydroxide to form the alkali metal halide, which is easily dissolved in water, so that no complicated operations are required after the reaction is completed. On the other hand, it is easier to control the reaction by gradually adding an aqueous solution of alkali metal hydroxide, and side reactions such as hydrolysis and saponification reactions are suppressed, resulting in a high yield of 2-heroacrylic acid ester. This is an industrially advantageous method for producing 2-haloacrylic acid esters.

EXAMPLES The present invention will be specifically explained below with reference to Examples, but it goes without saying that the present invention is not limited to these Examples.

Example 1 2, containing 300 ppm of hydroquinone monomethyl ether/L in a 30011 L glass flask equipped with a stirrer, thermometer, Dimroth condenser and dropping funnel.
Methyl 3-dichloropropionate 78, sy (o,
So mol) was prepared in advance.

Maintain the inside of the reaction vessel at 10% by weight while stirring.
Sodium hydroxide aqueous solution 48. O, p continuously 90
It was dripped over several minutes. After the dropwise addition was completed, stirring was continued for an additional 60 minutes while maintaining the temperature at 10°C. The reaction completed liquid was transferred to a separation funnel, 200 g of water and 50 m of carbon tetrachloride were added, and the mixture was shaken vigorously and allowed to stand. After separation into two layers, the aqueous layer was removed. Analysis of the obtained organic layer by gas chromatography revealed that 273
-Methyl dichloropropionate 5.711.2-Methyl chloroacrylate 39.61 (0.33 mol) were contained.

Example 2 Texture C35 instead of 50% sodium hydroxide aqueous solution
The same procedure as in Example 1 was carried out, except that 62.99% of IJum aqueous solution (wt% hydroxide) was continuously added dropwise over 95 minutes. Analysis of the obtained organic layer by gas chromatography revealed that methyl 2,3-dichloropropionate was 7.9. F
, methyl 2-chloroacrylate 38.1 , P (0,
32 mol).

79.6 g (0.40 mol) of 2,3-dichloropropionic acid-looputyl containing 300 ppm of methyl ether was charged in advance. While keeping the inside of the reaction vessel at 10°C and stirring, add 50% by weight sodium hydroxide aqueous solution 38.4
N was continuously added dropwise over 60 minutes. 10 after completion of dripping
Stirring was continued for an additional 40 minutes while maintaining the temperature at °C. Transfer the reaction completed liquid to a separatory funnel and add 20011L of water and 50m of carbon tetrachloride.
1 was added, shaken vigorously, and then left to stand. After separation into two layers, the aqueous layer was removed. Analysis of the obtained organic layer by gas chromatography revealed that 2,3-dichloropropionic acid-
Louptyl 7.71.2-Chloroacrylic acid-Looptil 41. o y (o, z smol) was included.

Claims (1)

[Claims] (1) General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼…………………………(
I) (However, in the formula, X_1 and X_4 represent halogen atoms,
_2 and X_3 each represent a hydrogen atom or a halogen atom. Further, R represents an alkyl group or an aryl group. ) is dehydrohalogenated in the presence of an aqueous solution of alkali metal hydroxide to form the general formula (II) ▲Mathematical formulas, chemical formulas, tables, etc.
I) (However, in the formula, X_2, X_3, X_4 and R are the same as the above general formula (I).) A 25 to 55% by weight aqueous solution of an alkali metal hydroxide in an amount equivalent to 0.9 to 2.0 mol per 1.0 mol of the propionate ester represented by is added over a period of 0.5 to 5.0 hours. A method for producing a 2-haloacrylic acid ester represented by the general formula (II), which comprises adding continuously or intermittently.