FI63013B - PROCEDURE FOR FRAMSTATION OF 2,6-DI-TERT -BUTYL-4-METHYLPHENOL - Google Patents

Description

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Patent- och ragictarttyralaan Antokin uttagd och iicUkrtffcM pubtewud. od (32) (33) (31) Pyydetty utuolltum —tegird prloritac (71) Sterlitamaxky Opytno-Promyshlenny Zavod po Proizvodstvu Izoprenovogo Kauchuka, Sterlitamak 10, Bashkirskaya ASSR, USSR (SU) (72) Ivan Egorovich Abramov, Sterlit

Felix Borisovich Gershanov, Sterlitamak, Bashkirskaya ASSR,

Vladimir Romanovich Dolidze, Sterlitamak, Bashkirskaya ASSR,

Nina Vasilievna Zakharova, Kazan, Alexandr Grigorievich Liakumovich,

Kazan, Jury Ivanovich Michurov, Sterlitamak, Bashkirskaya ASSR,

Vasily Dmitrievich Popov, Sterlitamak, Bashkirskaya ASSR,

Grigory Iosifovich Rutman, Sterlitamak, Bashkirskaya ASSR,

Zoya Stepanovna Shalimova, Sterlitamak, Bashkirskaya ASSR, USSR (SU) (7U) Oy Kolster Ab (5I +) Method for the preparation of 2,6-di-tert-butyl-1 + -methyl phenol -Förfarande för framställning av 2,6-di -tert-butyl-U-metylfenol

The invention relates to a process for the preparation of 2,6-di-tert-butyl-4-methylphenol.

2,6-di-tert-butyl-4-methylphenol is an effective stabilizer for various types of synthetic rubbers, it protects on vulcanates based on natural rubber, butadiene-styrene, iso-prene, butadiene-styrene, isoprene, butadiene, butadiene nitrile and chloroprene rubbers, aging by heat and partly by light and is also used in light and colored rubber products. 2,6-di-tert-butyl-4-methylphenol is used for thermal stabilization of polyethylene and polypropylene fibers and is also an effective food stabilizer.

A process for the preparation of 2,6-di-tert-butyl-4-methylphenol by hydrogenolysis of Ν, Ν-dimethyl (3,5-di-tert-butyl-4-hydroxy-benzyl) amine in a catalytic organic solvent medium has been widely used in the art. .

In particular, there is a process known in the art (GB Patent No. 1,229,480) for the preparation of 2,6-di-tert-butyl-4-methylphenol by hydrogenolysis of β, Ν-dimethyl (3,5-di-tert-butyl-4 -hydroxy-6301 3 benzyl) amine in decalin in the presence of a Ni-Al-Ti catalyst.

A disadvantage of the method previously known in the art is that during hydrogenolysis N, N-dimethyl (3,5-di-tert-butyl-4-hydroxybenzyl) amine is partially resinized in decalin; the isolated 2,6-di-tert-butyl-4-methylphenol contains about 5% of resin products which give it a yellow color.

In addition, the isolation of 2,6-di-tert-butyl-4-methylphenol from the reaction mixture requires concentrated distillation of the reaction mixture and solvent recovery, which makes the process more complicated and expensive.

The 2,6-di-tert-butyl-4-methylphenol prepared by said process can be used for foodstuffs only after a complex purification process, e.g. by concentration distillation or crystallization.

It is an object of the present invention to improve a process for the preparation of 2,6-di-tert-butyl-4-methylphenol by the catalytic hydrogenolysis of N, N-dimethyl (3,5-di-tert-butyl-4-hydroxybenzyl) amine using process technology. simplify, reduce the price of the product and improve its quality.

The invention is characterized in that the solvent is 2,6-di-tert-butyl-4-methylphenol, i.e. the final product. The use of 2,6-di-tert-butyl-4-methylphenol as a solvent allows the isolation process of 2,6-di-tert-butyl-4-methylphenol from the reaction mixture to be simplified by omitting the concentration distillation of the reaction mixture and the recovery of the solvent.

In addition, during hydrogenolysis in the presence of 2,6-di-tert-butyl-4-methylphenol, secondary resinization processes are inhibited, allowing 2,6-di-tert-butyl-4-methylphenol to be obtained in the desired purity without complicated purification steps and / or in a yield of 98.4%.

The product obtained is white, odorless and has a melting point of 69.9-0.1 ° C and meets the requirements of the food industry.

For a better understanding of the invention, the following example is provided.

EXAMPLE I

The process was carried out in a glass reaction vessel equipped with a thermometer, a Schott filter for better oxygen distribution, a coil for heating the hydrogen and a reflux condenser.

3 63013

90.0 g of molten catalyst ("Raney nickel type containing 50% Ni, 45% Al and 5% i with a particle size of 2-3 mm), 20 g of 2,6-di-tert-butyl-4 methylphenol, 20 g of N, N-dimethyl- (3,5-di-tert-butyl-4-hydroxybenzyl) amine The temperature in the reaction vessel was 110 ° C, the hydrogen flow rate was 25 ml / min, and the reaction time was 2 hours. After completion of the reaction, the product was removed from the reaction vessel to give 36.0 g of a white, odorless, crystalline product having a melting point of 69.9 C. The yield of 2,6-di-tert-butyl-4-methylphenol was 98.4 % of theory The quality of the obtained 2,5-di-tert-butyl-4-methylphenol meets the requirements of the food industry.