RU2239625C2 - Method for preparing beta-(4-hydroxy-3,5-di-tertiary-butylphenyl)-propionic acid salts - Google Patents

Abstract

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to the improved method for preparing β-(4-hydroxy-3,5-di-tert.-butylphenyl)-propionic acid salts. Method involves interaction of β-(4-hydroxy-3,5-di-tert.-butylphenyl)-propionic acid methyl ester with metal oxide taken among the following group: Ca, Ba, Zn at elevated temperature and pressure in an aqueous-alcoholic medium. Reaction is carried out at temperature 70-130^oC, under pressure 3-3.7 atm, in the presence of β-(4-hydroxy-3,5-di-tert.-butylphenyl)-propionic acid in the mole ratio ester : metal oxide : acid = 1.00:(0.45-0.55):(0.01-0.1), respectively, and the following addition of dioctyl phthalate as a solvent. Method provides enhancing selectivity and technological effectiveness of process and to improve quality of the end product.

EFFECT: improved preparing method.

2 tbl, 9 ex

Description

The invention relates to organometallic chemistry, and in particular to methods for producing salts of β- (4-hydroxy-3,5-di-tert-butylphenyl) propionic acid of the general formula

where Me is a metal selected from the group: Zn, Ba, Ca with valency II, which are used as stabilizers for polymers and additives to oils.

A compound is known which is a potassium salt of β- (4-hydroxy-3,5-di-tert-butylphenyl) propionic acid and having the structure

which is used in medicine as an anti-stress and anti-burn agent and in agriculture as a growth substance (Aging 1990, V.2, N 2, p. 125-153).

A known method of producing salts of β- (4-hydroxy-3,5-di-tert-butylphenyl) propionic acid by the interaction of methyl ester of β- (4-hydroxy-3,5-di-tert-butylphenyl) propionic acid (methylox) with an alkali metal hydroxide in an aqueous and / or alcoholic solution at elevated temperature and pressure, followed by the interaction of the obtained alkaline salt of propionic acid with an inorganic salt of the corresponding metal in an aqueous and / or alcoholic medium (RF patent No. 2150463, MKI C 07 C 59/52 51/41).

The disadvantages of this method is its multi-stage, the formation of mineralized wastewater, as well as the use of a significant amount of reagents, which negatively affects the cost of the product.

The closest in technical essence is the method of producing salts of β- (4-hydroxy-3,5-di-tert-butylphenyl) propionic acid by the interaction of methylox with metal oxide of the second group of the Periodic system in an aqueous and / or alcoholic solution at a temperature of 70- 100 ° C and a pressure of 1-4 atmospheres with a molar ratio of ether: metal oxide of 1.0: 1.0-1.05 (RF patent No. 2170723, MKI C 07 C 59/52, 51/41).

The disadvantage of this method is the low selectivity of the process for the target product (in the case of calcium or barium salts of β- (4-hydroxy-3,5-di-tert-butylphenyl) -propionic acid) due to the formation of metal side alkyl phenolates of the general formula

where R is CH ₂ CH ₂ COOCH ₃ ;

Me - Ca, Ba, Zn.

The presence of these metal alkyl phenolates in the target products gives the salts of β- (4-hydroxy-3,5-di-tert-butylphenyl) propionic acid a creamy tint, which prevents the use of these salts for the preparation of white polymeric materials. In addition, the target product is obtained in the form of a sticky clay-like mass, which makes it almost impossible to mix and unload the final product.

The technical task of the invention is to increase the selectivity of the process, improving the quality of the target product and improving the manufacturability of the process.

The technical problem is achieved by the fact that the process of obtaining salts of β- (4-hydroxy-3,5-di-tert-butylphenyl) propionic acid is carried out by the interaction of methylox with metal oxide of the second group of the Periodic system in an aqueous-alcoholic medium at a temperature of 70-130 ° C and a pressure of 3-3.7 atmospheres in the presence of β- (4-hydroxy-3,5-di-tert-butylphenyl) propionic acid, the molar ratio of ether: metal oxide: acid being 1.0: 0.45- 0.55: 0.01-0.1. After the reaction, dioctyl phthalate is added to the mixture and methanol is distilled off.

The reaction for the preparation of salts of β- (4-hydroxy-3,5-di-tert-butylphenyl) propionic acid is described by the following equation:

where Me is a metal selected from the group Ca, Ba, Zn.

It was unexpectedly found that carrying out the process in the presence of β- (4-hydroxy-3,5-di-tert-butylphenyl) propionic acid provides a higher process selectivity of 98.5-99.5 wt.%. Apparently, this is due to the fact that metal oxides at the initial time mainly interact with β- (4-hydroxy-3,5-di-tert-butylphenyl) propionic acid, which exhibits stronger acidic properties than methylox, with the formation of the target product, and then the reaction of methylox with metal oxides proceeds according to the claimed reaction mechanism without the formation of by-products, that is, the addition of β- (4-hydroxy-3,5-di-tert-butylphenyl) propionic acid inhibits the formation of by-products giving their target product is a creamy tint.

In addition, obtaining the final product in the form of a 20-25% dioctyl phthalate solution (homogeneous suspension) makes the process more technologically advanced.

The proposed method for the preparation of salts of β- (4-hydroxy-3,5-di-tert-butylphenyl) propionic acid is carried out as follows.

Solvent, methylox and β- (4-hydroxy-3,5-di-tert-butylphenyl) -propionic acid are charged into an enameled iron reactor equipped with a mechanical stirrer with a shutter and a heating jacket. Then stirred with heating until complete dissolution of the reagents. Then, a mixture of a metal oxide with an aliphatic alcohol (water) stoichiometrically the required amount of the desired metal at a temperature of 70-130 ° C is dosed in portions. Maintain the mixture at this temperature and vigorous stirring for 30-60 minutes. Next, dioctyl phthalate is added to the mixture in a ratio of 1: 3-4 (propioic acid salt: dioctyl phthalate) and methanol is distilled off. Get the target product with a yield of 98.0-99.0% of theoretical. The target product has a white color, which is determined on KFK-2-UHL 4.2 by a known method.

The optical density of a solution of salts of β- (4-hydroxy-3,5-di-tert-butylphenyl) propionic acid in dioctyl phthalate to a value of 0.14 corresponds to a white product, and above to a cream color.

The starting reagents must meet the following requirements:

CaO - GOST 8677-76;

BaO - GOST 10203-78;

ZnO - GOST 10262-73.

In addition, for this synthesis, methyloxy containing impurities of β- (4-hydroxy-3,5-di-tert-butylphenyl) propionic acid in the claimed amounts can be used.

The essence of the method and its industrial applicability is confirmed by the following examples.

Example 1

292 g (1 mol) of methylox and 2.78 g (0.01 mol) of β- (4-hydroxy-3,5-di-tert-butylphenyl) are charged into an enameled iron reactor equipped with a mechanical stirrer with a shutter and a heating jacket. ) -propionic acid. The starting reagents are dissolved in 0.5 l of methyl alcohol and the calculated amount of water to obtain a less viscous reaction mass to improve the processability.

Next, an aqueous (aqueous-alcoholic) CaO solution (29.16 g, or 0.52 mol) is metered into the alcohol solution of the reagents with constant stirring of the reaction mixture and heating to 80 ° C for 25 minutes. After dosing, the mixture was incubated for 30-40 minutes and then 0.9 L of dioctyl phthalate was added and methanol was distilled off. Obtain 291.4 g or 98.11 wt.% From theoretical calcium salt in a solution of dioctyl phthalate. The selectivity of the process is 98.11%.

The optical density of the solution of the calcium salt of β- (4-hydroxy-3,5-di-tert-butylphenyl) propionic acid in dioctyl phthalate is 0.064, which corresponds to a white product.

Example 2

294.9 g of methylox (1 mol) containing 0.01% by weight of β- (4-hydroxy-3,5-di-tert-butylphenyl) -propionic acid are charged into the reactor described in Example 1. The starting reagents are dissolved in 1.0 L of methyl alcohol.

Next, an aqueous-alcoholic solution of CaO (27.44 g, or 0.5 mol) is metered into the alcohol solution of methylox with constant stirring of the reaction mixture and heating to 125 ° C for 40 minutes. After dosing, the mixture is kept for 30 minutes and then cooled to 20-25 ° C, then 1 l of dioctyl phthalate is added to the reaction mass and methanol is distilled off. Get 292.84 g, or 98.6 wt.%, From theoretical calcium salt in a solution of dioctyl phthalate. The selectivity of the process is 97.62%.

The optical density of the solution of the calcium salt of β- (4-hydroxy-3,5-di-tert-butylphenyl) propionic acid in dioctyl phthalate is 0.072, which corresponds to a white product.

Examples 3-9 are presented in table 1, carry out similarly to examples 1 and 2.

Table 2 presents the melting temperature and elemental composition of the target products.

Thus, as can be seen from the presented examples, the proposed method allows to obtain salts of β- (4-hydroxy-3,5-di-tert-butylphenyl) propionic acid with high selectivity, while the target products are white, which allows their use to obtain white polymeric materials, and the method is highly technological.

Claims (1)

The method of obtaining salts of β- (4-hydroxy-3,5-di-tert-butylphenyl) propionic acid by the interaction of methyl ester of β- (4-hydroxy-3,5-di-tert-butylphenyl) propionic acid with metal oxide, selected from the group of Ca, Ba, Zn, at elevated temperature and pressure in an aqueous-alcoholic medium, characterized in that the reaction is carried out at a temperature of 70-130 ° C and a pressure of 3-3.7 atmospheres in the presence of β- (4-hydroxy- 3,5-di-tert-butylphenyl) propionic acid with a molar ratio of ether: metal oxide: acid 1.00: 0.45-0.55: 0.01-0.1, followed by the addition of dioctyl phthalate to as a solvent.