The way to obtain 3,5-di-tert.-butyl-4-hydroxyphenylacetate

 

(57) Abstract:

Usage: esters alteromonas phenol, substituted benzoylacetate, stabilizers, antioxidant. The inventive receive 3,5-di-tert-butyl-4-hydroxyphenylacetate interaction 3,5-di-tert-butyl-4-hydroxybenzylideneamino with acetic anhydride at 20 - 55 for 15 - 25 min, during the precipitation of the product with hot water. Exit 90 - 96%.

The invention relates to the production of additives to polymeric materials, and in particular to a method for producing 3,5-di-tert-butyl-4 - hydroxyphenylacetate (formula I), which is the initial product in the synthesis of valuable phenolic stabilizer 2,4,6-tri-(3,5-di-tert-butyl-4-hydroxybenzyl) mesitylene (see B. Gorbunov N. and other Chemistry and technology of stabilizers in polymeric materials. M.: Chemistry, 1981, S. 295).

HOCH2-O--CH3< / BR>
(I)

A method of obtaining 3,5-di-tert-butyl-4-hydroxyphenylacetate by reacting 2,6-di-tert-butylphenol with acetic acid and parathormon in the presence of diethylamine scheme

HO+ CH2O+CH3COOH __ HOCH2OCH3+H2O, followed by separation of the target product.

In accordance with this method the interaction of reagents spend PU diethyl ether and water, separation and washing of the ether layer, removal of the ether under vacuum. The yield of the target product based on the phenol is 58% , so pl. 103-105about(See Shell patent N 6909355, Netherlands, 1969).

The disadvantages of this method are the long duration of the process, the hazard process through the use of diethyl ether, the small yield of the target product.

The closest in technical essence and the achieved effect is the way to obtain 3,5-di-tert-butyl-4-hydroxyphenylacetate by reacting 3,5-di-tert-butyl-4-hydroxybenzylidene - tiramina with acetic anhydride in the environment of acetone scheme

with subsequent isolation of the target product.

3,5-di-tert-Butyl-4-hydroxybenzyl - methylamine, acetic anhydride and acetone taken in the ratio of 1 mole : 1-2 mole : 70 moles, respectively, and boiled for 1H. Then the solvent is removed in vacuum, the residue is dissolved in ether or chloroform, washed with 5% hydrochloric acid, dried, after which the organic layer is separated, the solvent is distilled off in vacuum. The residue is recrystallized from heptane. The yield of the target product 100% , so pl. 107-108about(See Izv. An SSSR, ser. chem., N 12, 1989, S. 2765-70).

The disadvantages of the mi energy consumption for its removal and inefficient use of the reactor, the loss generated during the reaction valuable solvent is dimethylacetamide, which occurs when washing the product with 5% hydrochloric acid; the duration and complexity of the stage of selection of the target product, which includes a number of operations.

The basis of the invention is to create a simple, high-tech waste-free way to obtain 3,5-di-tert-butyl-4-hydroxyphenylacetate high purity with high yield with less reaction time and selection of the target product.

The problem is solved in that in the method of obtaining 3,5-di-tert-butyl-4-hydroxyphenylacetate by reacting 3,5-di-tert-butyl-4-hydroxybenzylideneamino with acetic anhydride, followed by separation, the process is conducted at 20-55aboutC for 15-25 min, and the selection of the target product are hot water, 3,5-di-tert-butyl-4-hydroxybenzylideneamino and acetic anhydride is introduced into the reaction in a ratio of 1 mole : 1-1,1 mol, respectively, and a mixture of dimethylacetamide with water separated by distillation.

Increasing the reaction temperature above 55aboutC leads to a reduction of yield and purity of the target product.

3,5-di-tert-Butyl-4-hydroxybenzoate - tat has a temperature of plaul usnot invention.

P R I m e R 1. The reactor was placed 10 g (of 0.038 mole) of 3,5-di-tert-butyl-4-hydroxybenzylideneamino and 3,62 ml (of 0.038 mol) of acetic anhydride. The process is conducted under stirring in nitrogen atmosphere. The temperature of the reaction mass support 20-25aboutC. Mixing are within 25 minutes Then the reaction mass is added 20 ml of hot water and mix thoroughly. The residue is separated on a filter and washed with 10 ml of water. Exit dried 3,5-di-tert-butyl-4-hydroxyphenylacetate 10.2 g (96,5% ), so pl. 107-108aboutC. a Mixture of dimethylacetamide with water separated by distillation.

P R I m m e R 2. The reaction is carried out as in example 1 but the reaction take 10 g (of 0.038 mole) of 3,5-di-tert-butyl-4-hydroxybenzylideneamino and 4 ml (0,042 mole) of acetic anhydride.

The yield of the target product 10,45 g (98.9 per cent), so pl. 107-108aboutC.

P R I m e R 3. The reaction is carried out as in example 1, but the temperature of the reaction mass support 25-30aboutWith that reaction are 20 minutes

The target product yield 10.4 g (98.4 per cent), so pl. 106-108aboutC.

P R I m e R 4. The reaction is carried out as in example 1, but the temperature of the reaction mass support 35-40aboutWith that reaction are 20 minutes

The yield of the target products of 10.25 g (97%), so pl. 104-106aboutC.

P R the lead 15 minutes

The yield of the target product of 10.2 g (96,5%), so pl. 103-105aboutC.

P R I m e R 6 (on prototype. Time of carrying out the reaction as in the claimed object). The reactor was placed 10 g (of 0.038 mole) of 3,5-di-tert-butyl-4-hydroxybenzylidene - thylamine, 4 ml (0,042 mole) of acetic anhydride, 190 ml of acetone. The reaction mixture is boiled under nitrogen atmosphere for 25 minutes and Then the acetone is distilled off in vacuum. The residue is dissolved in 30 ml of chloroform, washed with 5% hydrochloric acid, then with water until neutral, dried over magnesium sulfate. The chloroform is distilled off in vacuum.

The target product yield 9.6 g (90,9%), pl. 97-100aboutC.

Getting 3,5-di-tert-butyl-4-hydroxyphenylacetate by the present method allows 4-5 times to reduce the volume of the reactor at the same loading of reagents, reduce in 2 times the reaction time, to simplify the extraction of the target product, 3,5-di-tert-butyl-4-hydroxyphenylacetate get high purity with high yield, there is no need for additional cleaning.

The inventive method is a waste, because obtained during the reaction dimethylacetamide is allocated and used as a valuable dipolar aprotic solvent (see "Advances in organic chemistry" under the em interaction 3,5-di-tert.-butyl-4-hydroxybenzylideneamino with acetic anhydride, followed by separation of the target product, characterized in that the process is conducted at 20 to 55oC for 15 to 25 min, and the product emit hot water.

 

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