JPS6094935A - Production of 2-(4-hydroxyphenoxy)alkanoic acid - Google Patents

Abstract

PURPOSE:To produce the titled substance useful as a raw material of herbicide, in high yield, by using hydroquinone and a compound such as ethyl chloropropionate as raw materials, and reacting the materials with an alkali metal hydroxide, thereby carrying out the condensation and the hydrolysis of the product at the same time. CONSTITUTION:The titled compound is produced by reacting hydroquinone or a hydroquinone salt and the compound of formula (X is Cl or Br; R<1> is H or lower alkyl; R<2> is lower alkyl) with an alkali metal hydroxide preferably sodium hydroxide, at 0-100 deg.C, preferably 50-80 deg.C, and hydrolyzing the produced 2-(4- hydroxyphenoxy)-alkanoic acid ester simultaneously to the above condensation reaction. The amount of the alkali metal hydroxide is preferably >=2mol per 1mol of the compound of formula. The titled compound is useful as a raw material of herbicide containing a heterocyclic ether phenoxyfatty acid derivative as an active component.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing 2-(4-hydroxyphenoxy)alkanoic acids. More details.

The present invention provides hydroquinone or a salt of hydroquinone with the general formula (1) % formula % (1) (wherein, X represents a chlorine or bromine atom, R1 represents hydrogen or a lower alkyl group, and R2 represents a lower alkyl group). 2-(4-hydroxyphenoxy) produced by reacting the represented compound with an alkali metal hydroxide
The present invention relates to a method for producing 2-(4-hydroxyphenoxy)alkanoic acid, which comprises simultaneously hydrolyzing alkanoic acid esters.

2-(4-hydroxyphenoxy)alkanoic acid esters are disclosed in JP-A-56-16475 and JP-A-54-22.
It is useful as an intermediate for compounds disclosed in JP-A No. 371, JP-A-53-40767, and the like. For example, it is useful as a raw material for producing a highly effective herbicide containing a heterocyclic ether phenoxy fatty acid derivative as an active ingredient, as described in JP-A-56-16475.

Examples of methods for producing 2-(4-hydroxyphenoxy)alkanoic acid esters include a method shown by the following reaction formula disclosed in JP-A No. 56-59718.

There is also a method shown by the following reaction formula disclosed in International Application Publication No. 82100639.

Furthermore, there is a method shown in the following reaction formula disclosed in European Patent No. 82413.

(In the formula, X represents a chlorine or bromine atom, and R represents a lower alkyl group.) The melting point is 228-230°C, whereas the melting point of 2-(4-hydroxyphenoxy)propionic acid required by the present inventors is 147-150°C.

Furthermore, the method disclosed in International Application Publication No. 82100639 has a low production rate in the step of synthesizing persulfate ester and requires a large number of steps, so it cannot be said to be industrially preferred.

Furthermore, the reaction disclosed in European Patent No. 82413 is a homogeneous system, and as shown in the following equation, sequential reactions occur, and unless the conversion rate is lowered, a large amount of dimer will be produced. Therefore, industrially, the cost becomes high due to the operation for recovering a large amount of hydroquinone. Also, reduce the reaction rate to reduce unreacted hydroquinone.

(In the formula, 2 for kl+ indicates the reaction rate, and R indicates a lower alkyl group.) If the reaction rate is increased, the production rate of dimers increases and the yield significantly decreases.

The present inventors have conducted extensive research into an excellent method for producing 2-(4-hydroxyphenoxy)alkanoic acid, since these methods are not industrially advantageous.

Overcoming the shortcomings of the conventional method, 2-(4
-Hydroxyphenoxy)alkanoic acid was discovered and the present invention was completed.

That is, in the present invention, condensation and hydrolysis of the product were performed simultaneously as shown in the reaction formula below in order to improve the selectivity. As the selectivity improved, the amount of hydroquinone recovered per time was reduced (and the yield also improved).

(In the formula, R represents a lower alkyl group.) General formula (1):
In XCHR COOR2 (1), chlorine or bromine is used for X, but in the case of chlorine, potassium iodide can be used as a catalyst to improve the reaction rate of the condensation reaction. Further, a lower alkyl group is used as R2, and methyl and ethyl groups are preferred because they have a small molecular weight and a high rate of hydrolysis of the intermediate.

As the solvent, alcohols such as methanol, ethanol; isopropanol, ethylene glycol, and cellosolves are preferable. Further, solvents such as dimethylformamide, dimethyl sulfoxide, and 1,3-dimethylimidazolidinone can also be used, and these and the above-mentioned alcohols may be mixed for use. These solvents may contain some water. Alkali metal hydroxides include lithium hydroxide,
Preferred are sodium hydroxide and potassium hydroxide.

Considering economic efficiency, sodium hydroxide is most preferred.

The amount used is based on the raw material, i.e., XCHRICOOR2 (
In the formula, R1 is hydrogen or a lower alkyl group, and R2 is a lower alkyl group. however,
When using the sodium salt of hydroquinone, the amount may be equimolar or more. The sodium salt of hydroquinone may be prepared in advance in the system by adding sodium methylate or sodium ethylate, or by reacting hydroquinone with an equivalent molar amount - twice the molar amount of alkali hydroxide.

It may be used in isolation.

The reaction temperature varies depending on the raw materials used, the alkali metal, the type of solvent, etc., but is preferably 0 to 100°C. Considering reaction rate 9 selectivity, the temperature is most preferably 50 to 80°C. Since the produced acid is mostly used as an ester, it can be purified by distilling the esterified product to separate it from the dimer.

In addition, when the reaction solvent 9 has the same alkyl group as the desired ester, it is also possible to obtain the ester by making it acidic with hydrogen chloride gas, followed by ordinary post-treatment and distillation.

In order to obtain 2-(4-hydroxyphenoxy)propionic acid with good purity, the obtained ethyl 2-(4-hydroxyphenoxy)propionate is hydrolyzed using at least twice the mole of sodium hydroxide, and then hydrolyzed with hydrochloric acid. The solid may be acidified, cooled, and precipitated by filtration, followed by recrystallization with an aqueous solvent. The melting point of the white solid thus obtained is 147-1
The temperature was 50°C.

This will be explained in more detail below with reference to Examples.

The present invention is not limited to these.

22 g of hydroquinone, 1 g of potassium iodide, and 120 g of ethanol were placed on a car tray, and after purging with nitrogen, 20 g of sodium hydroxide was added to bring the temperature to 80°C. After 19.3 g of ethyl chloropropionate was added dropwise over time t and s, the mixture was stirred for 1 hour. Add 200g of water.

The pH was adjusted to 1 using hydrochloric acid, and the mixture was extracted twice with 200 g of ethyl acetate, and the ethyl acetate was distilled off. The obtained solid was methylated with diazomethane to obtain the following composition.

Hydroquinone・−・−・−−−−−−−・36
．． 2 mol% 2-(4-hydroxyphenoxy) propionic acid-1--1-11--
60.1 mol% dimer-1--11--・--
---・・-・-------・-・・-3.6 mol% To this composition, 100 g of ethanol and 1 g of concentrated sulfuric acid were added, and after refluxing for 1 hour, the ethanol was distilled off, 100 g of water, and toluene were added. Add 100g and filter out insoluble matter.

After separation, the toluene layer was washed twice with water and the toluene was distilled off. The residue was purified under reduced pressure to obtain 23 g of ethyl 2-(4-hydroxyphenoxy)propionate as a light brown liquid.

Boiling point: 135-140°C/1n+mHg.

1 m 22 g of hydroquinone, 1 g of potassium iodide, and 120 g of ethanol were charged, and the mixture was purged with nitrogen. Then, 5.0 g of sodium hydroxide and 24.3 g of 28% methyl alcohol were added, and the temperature was raised to 80°C. Ethyl chloropropionate 24.7g
was added dropwise over 2.5 hours, and the mixture was stirred for 1 hour. 200g water
The mixture was adjusted to pH 1 with hydrochloric acid, extracted twice with 200 g of ethyl acetate, and the ethyl acetate was distilled off. The obtained solid was methylated with diazomethane to obtain the following composition.

Hydroquinone...-----------18,1
Mol% 2-(4-hydroxyphenoxy) propionic acid...--1----1o, 2 mol% dimer---1---1--- m---
・----1...-41.7 mol% The same post-treatment as in Example 1 was carried out, and ethyl 2-(4-hydroxyphenoxy)propionate was converted into a light brown liquid by vacuum blackening. 27.
I got 7g.

Boiling point: 135-140°C/l mmHg.

Presentation■1 Hydroquinone 11g, potassium iodide 0.5g.

After charging 70 g of ethanol and purging with nitrogen, 4.6 g of metallic sodium was dissolved, and 6 g of sodium hydroxide was further added to bring the temperature to 80°C. Ethyl chloropropionate 13.
After 7 g was added dropwise over 2.5 hours, the mixture was stirred for 1 hour. After blowing in 6.2 g of hydrogen chloride gas and refluxing for 1 hour, ethanol was distilled off under reduced pressure. 100g water, 100g l-luene
The insoluble matter was filtered out, separated into 9 liquids, and the toluene layer was washed twice with water and the toluene was distilled off. The residue was evaporated to 2-(4
14 g of ethyl -hydroxyphenoxy)propionate was obtained as a light brown liquid.

Boiling point: 135-b 22 g of hydroquinone, 1 g of potassium iodide, and 120 g of ethanol were charged, and after purging with nitrogen, 20 g of sodium hydroxide was added to bring the temperature to 80°C. After 24.7 g of methyl chloropropionate was added dropwise over 1.5 hours, the mixture was stirred for 1 hour. The same post-treatment as in Example 1 was performed to obtain the following composition.

Hydroquinone−・−・−−−−−−−・−・・−・−
34.5 mol% 2-(4-hydroxyphenoxy) propionic acid--------------
・60.9 mol% dimer・・-----
−−・−−−−−−−−−−−−−−4,6 mol%
Example 1 J- Prepared 22g of hydroquinone and 120g of ethanol.
After purging with nitrogen, add 20g of sodium hydroxide and heat to 80°C.
And so. After 25 g of ethyl bromopropionate was added dropwise over 0.5 hours, the mixture was stirred for 1 hour.

The same post-treatment as in Example 1 was performed to obtain the following composition.

Hydroquinone...-----------
33.0 mol% 2-(4-hydroxyphenoxy) propionic acid---1-・-----------5
9,'O mol% dimer ----111-----
・------------------------ 8.2 mol% implementation■ 11 g of ehydroquinone, 60 g of ethanol, and 0.5 g of potassium iodide were charged, and after purging with nitrogen, 10 g of sodium hydroxide was added and heated to 80℃. did. 9g of ethyl chloroacetate
was added dropwise over 1.5 hours, and the mixture was stirred for 1 hour. The same post-treatment as in Example 1 was performed to obtain the following composition.

Hydroquinone-・-----1---------・-33
, 0 mol% 2-(4-hydroxyphenoxy) propionic acid--------...--
65, 0 mol% dimer...--1----------
−−−−−−−−−−−−−−−−−−2.0 mol% Patent applicant Nissan Chemical Industries, Ltd. Procedural amendment (spontaneous) +a December 1982 - Director General of the Patent Office Wakasugi Mr. Kazuo 1 Display of the case Patent Application No. 202388 of 1982 Title of the invention 2 Process for producing -(4-hydroxyphenoxy)alkanoic acid 3 Relationship with the person making the amendment Case Patent applicant address 101 Chiyoda-ku, Tokyo 3-7-14 Kanda Nishikicho
Detailed Description of the Invention Column 5 of the Specification Subject to Amendment Contents of the Amendment (1) Reaction formula on page 3, line 9 of the specification.

" Correct.

(2) r stated on page 8, line 19 of the specification
Correct ethyl chloropropionate j to "ethyl α-chloropropionate".

(3) "Propionic acid" written on page 9, line 7 of the specification is corrected to "methyl propionate."

(4) r stated on page 10, line 1 of the specification
"Ethyl chloropropionate" is corrected to "ethyl α-chloropropionate."

(5) "
"propionic acid" is corrected to "methyl propionate J.

(6) "Ethyl chloropropionate j" written on page 10, line 19 of the specification is corrected to "ethyl chlorpropionate".

(8) "rpropionic acid" written on page 11, line 18 of the specification is corrected to "methyl propionate."

(9) "
"Ethyl bromopropionate" is corrected to "ethyl α-bromopropionate."

(10) As stated in page 12, line 9 of the specification, “
"propionic acid" is corrected to "methyl propionate J.

(11) rpropionic acid j stated on page 12, line 20 of the specification is corrected to "methyl acetate".

Procedural amendment (voluntary) October 128, 1982 1. Indication of the case 1988 Patent Application No. 202388 2. Title of the invention 2. Process for producing -(4-hydroxyphenoxy)alkanoic acid 3. Person making the amendment Relationship with the case Patent applicant address: 3-7-14 Kanda Nishikicho, Chiyoda-ku, Tokyo 101
Claims column of the specification subject to amendment and detailed booklet of the invention
I ■■ can withstand small ------ 5,? ! Correct content (1) The amended claims column is amended as shown in the attached sheet.

(2) On page 6 of the specification, between the 5th and 6th lines from the bottom, there is a statement that says ``If R1 is an alkyl group, an optically active substance exists.If optically active XCHRI COOR2 is used, the same In this case, the reaction at the asymmetry 2-carbon atom is preferentially carried out by Walden inversion, and the desired optically active substance is obtained.'' is corrected.

(3) On page 13 of the specification, after the first line, the following is amended.

"Example 7 11g of hydroquinone and 60g of ethanol were charged, and the atmosphere was replaced with nitrogen. After that, 12g of sodium hydroxide was added and the temperature was raised to 80°C.
After cooling to 30°C, 9.6 g of ethyl p-α-chloropropionate was added and reacted for 5 hours.
The reaction was carried out at °C for 1 hour. After the reaction, 1 g of hydrochloric acid gas I was added and further 60 g of Hensen was added to carry out azeotropic dehydration. The solvent was distilled off, water and toluene were added for extraction, and the toluene was removed to obtain 12 g of ethyl d-2-(4-hydroxyphenoxy)propionate.

[α) S'-+25° (measured with 1% chloroform solution)” Attached Claims (1) Hydroquinone or a salt of hydroquinone and general formula CI
) XCHRI COOR2 (earth) (wherein, 2-(4-hydroxyphenoxy) produced by reaction
A method for producing 2-(4-hydroxyphenoxy)alkanoic acid characterized by simultaneously hydrolyzing alkanoic acid esters. Sukuma-class dispatch

Claims (1)

[Claims] (1) Hydroquinone or a salt of hydroquinone and the general formula (1)
') 2-(4-hydroxyphenoxy) produced by reacting with
A method for producing 2-(4-hydroxyphenoxy)alkanoic acid, characterized by simultaneously hydrolyzing alkanoic acid esters.