CS270548B1 - Preparation of 2-Atyl-6-methyl-N- (1'-methoxy-2'-propyl) aniline - Google Patents

Abstract

A method for preparing 2-ethyl-6-methyl-N-(1-methoxy-2-propyl)aniline by hydrogenation alkylation of 2-ethyl-6-methylaniline with methoxypropanone in the presence of a platinum hydrogenation catalyst and trihydrogenphosphoric acid or sulfuric acid as a proton catalyst has been solved. The used platinum hydrogenation catalyst is filtered off from the resulting reaction mixture, the filtrate is mixed with activated carbon used in an amount corresponding to 1 to 5 times the amount of proton catalyst used, the volatile components consisting of 1-methoxy-2-propanol, methoxypropanone and water are removed under vacuum and stirring, the liquid phase of the desired reaction product is filtered off from the deethylation residue and the solid component consisting of activated carbon and the used proton catalyst as such or its components are separated by adding 1-methoxy-2-propanol and/or methoxypropanone and are returned by filtration, as well as the isolated platinum hydrogenation catalyst, 1-methoxy-2-propanol and methoxypropanone, to the next process cycle. The solution can be used in the chemical industry in the production of plant protection products.

Description

The invention relates to a process for the preparation of 2-ethyl-6-methyl-N- [1-methoxy-2-propyl] aniline. Said compound is known as an intermediate for the production of chemical plant protection products.

2-Ethyl-6-methyl-N- [1'-methoxy-2'-propyl] aniline can be prepared by reacting 2-ethyl-6-methyllaniline and 2-bromo-1-methoxypropane, condensing 2-ethyl-6-methylaniline with methoxypropanone and subsequent hydrogenation of 2-ethyl-6-methyl-N- (1'-methoxy-2'-propylidene) arphilin (AO 270 153, AO 270 154) or by hydrogenation alkylation of 2-ethyl-6-methylaniline with methoxypropanone on platinum catalyst / CS AO 169 841, AO 266 994, AO 266 995, AO 266 996, AO 267 385 /. The hydrogenation alkylation is carried out in a solvent such as methanol, ethanol, 1-methoxy-2-propanol and in the presence of a proton catalyst such as acetic acid, hydrochloric acid, trihydrogenphosphoric acid, or others. The disadvantage of the hydrogen alkylation process thus carried out is the difficulty of isolating the proton catalyst from the reaction mixture in order to reuse it in the process in order to improve its economy and ecology. This is because the most effective proton catalysts, such as trihydrogenphosphoric acid and sulfuric acid, are present in the resulting reaction mixture in the form of quaternary salts with 2-ethyl-6-methyl-N- [1'-methoxy-2'-propyl] aniline and after distilling off the volatile fractions! during its isolation, they remain insoluble in a semi-solid consistency, while they adhere to the walls of the distillation apparatus, from which they are difficult to remove mechanically. After separation of 2-ethyl-6-methyl-N- [1'-methoxy-2'-propyl] aniline, it is necessary to dissolve said quaternary salts preferably at elevated temperature, e.g. in water, 1-methoxy-2-propanol or methoxypropanone and then either used in a hydrogen alkylation process or by decomposition with hydroxide to liberate and isolate the bound reaction product bound therein.

The process for the preparation of 2-ethyl-6-methyl-N- (1'-methoxy-2'-propyl) aniline by the hydrogenation alkylation of 2-ethyl-6-methylaniline with methoxypropanone in the presence of 1-methoxy-2-propanol in the presence of a platinum hydrogenation solution eliminates these drawbacks. of catalyst and trihydrogenphosphoric acid or sulfuric acid as a proton catalyst, returning the used catalysts, 1-methoxy-2-propanol and methoxypropanone isolated from the resulting reaction mixture to the next process cycle, according to the invention. The invention is based on the fact that, after filtering the spent platinum hydrogenation catalyst from the resulting reaction mixture, the filtrate is mixed with activated carbon used in an amount corresponding to 1 to 5 times the amount of proton catalyst used and freed of volatiles consisting of methoxypropanone by vacuum and distillation. 1-methoxy-2-propanol and water. From the distillation residue, the liquid phase consisting of 2-ethyl-N- (1'-methoxy-2'-propyl) aniline and the solid consisting of the active and used proton catalyst as such or its components separated by the addition of 1-methoxy-2- propanol and / or methoxypropanone and filtration is used in the next cycle of the process.

The following examples illustrate but do not limit the scope of the invention.

Example 1

A mixture of 6.0 g of 2-ethyl-6-methylaniline, 6.0 g of methoxypropanone, 15.4 g of 1-methoxy-2-propanol, 0.21 g of 85% trihydrogenphosphoric acid with 60 mg of platinum catalyst on activated carbon as support with containing 1% platinum was hydrogenated in an autoclave at 50 ° C and a hydrogen pressure of 5.0 MPa for 3 hours. After cooling the autoclave, the platinum catalyst was removed by filtration, and 0.4 g of powdered activated carbon was added to the filtrate. With stirring under a water pump vacuum, the reaction mixture was concentrated at a bath temperature of 100 ° C. After distilling off the volatiles (water, 1-methoxy-2-propanol and methoxypropanone), the distillation residue was filtered. The filtrate is the desired product 2-ethyl-6-methyl-N- [1'-methoxy-2'-propyl] aniline. A mixture of activated carbon and used proton catalyst remained for filtration, which was suspended in 15.4 g of 1-methoxy-2-propanol and separated by filtration into activated> CS 270 548 B1 carbon and a solution of proton catalyst, which were used in the same way as isolated platinum hydrogenation. catalyst, 1-methoxypropanone and methoxy-2-propanol in the next cycle of the process.

Example 2

The hydrogenation alkylation was performed with a mixture of 6.0 g of 2-ethyl-6-methylaniline, 6.0 g of methoxypropanone, 15.4 g of 1-methoxy-2-propanol, 0.21 g of 85% trihydrogenphosphoric acid and 60 mg of platinum catalyst for activated carbon as a carrier containing 1% platinum in an autoclave at 50 ° C and a hydrogen pressure of 5 MPa for 3.5 hours. After cooling the autoclave, the platinum catalyst was filtered off and 1.0 g of powdered activated carbon was added. Water, methoxypropanol and methoxypropanone were distilled off with stirring under a water pump vacuum so that the temperature of the distilled mixture did not exceed 110 ° C. The 2-ethyl-6-methyl-N- (1'-methoxy-2'-propyl) aniline was filtered off from the distillation residue from activated carbon with an adsorbed proton catalyst, which was used for further hydrogenation alkylation as a proton catalyst.

Claims (1)

And the proton catalyst solution used as well as the isolated platinum hydrogenation catalyst, 1-methoxypropanone and methoxy-2-propanol in the Saline cycle of the process. Example 2 Hydrogenation alkylation was performed with a mixture of 6.0 g of 2-ethyl-6-methylaniline, 6.0 g of methoxypropanone, 15.4 g of 1-methoxy-2-propanol, 0.21 g of 85% trihydrogenphosphoric acid. and 60 mg of activated carbon platinum catalyst as carrier containing 1% platinum in the autoclave at 50 ° C and 5 MPa hydrogen pressure for 3.5 hours. After the autoclave was stored, the saplatin catalyst was filtered off and 1.0 g of activated carbon powder was added. Water, methoxypropanol and methoxypropanone were distilled off under agitation of the water pump so that the temperature of the distilled mixture did not exceed 110 ° C. From the distillation residue, 2-ethyl-6-methyl-N- (1'-methoxy-2'-propyl) aniline was filtered off from activated charcoal with the adsorbed proton catalyst, which was used in the other hydrogenation alkylation and protroton catalyst. OBJECT OF THE INVENTION Preparation of 2-ethyl-6-methyl-N- (1'-methoxy-2'-propyl) aniline by hydrogenation alkylation of 2-ethyl-6-methylaniline with methoxypropanone in 1-methoxy-2-propanol and in the presence of a platinum hydrogenation catalyst and of trihydrogenphosphoric acid or sulfuric acid as a proton catalyst with the return of the catalysts used, 1-methoxy-2-propanol and methoxypropanone, isolated from the resulting reaction mixture into a 3-cycle hydrogenation alkylation cycle, characterized in that filtering off the spent hydrogenation catalyst from the resulting reaction mixture, the filtrate is mixed with activated charcoal used in an amount corresponding to 1 to 5 times the amount of the proton catalyst used, the volatiles are removed by distillation under distillation, the liquid phase is filtered off from the distillation residue; ethyl 6-methyl-N- (1'-methoxy-2'-propyl) aniline and a solid consisting of and The activated carbon and the proton catalyst used as such or its components delayed by the addition of 1-methoxy-2-propanol and / or methoxypropanone and returned to the 3-cycle process by filtration. and