CS267385B1

CS267385B1 - A method for preparing 2,6-dialkyl-N- (r-methoxy-2-propyl) anilines

Info

Publication number: CS267385B1
Application number: CS884269A
Authority: CS
Inventors: Emanuel Ing Csc Beska; Vaclav Rndr Csc Konecny; Juraj Ing Tuleja; Miroslav Ing Kriz; Karol Rndr Fiedler; Andrej Ing Handlovsky; Ladislav Roller; Stefan Ing Wenchich; Ludovit Rndr Csc Kuruc; Vojtech Ing Kubala; Milan Ing Csc Hronec
Original assignee: Beska Emanuel; Konecny Vaclav; Tuleja Juraj; Kriz Miroslav; Fiedler Karol; Handlovsky Andrej; Ladislav Roller; Wenchich Stefan; Kuruc Ludovit; Kubala Vojtech; Hronec Milan
Priority date: 1988-06-20
Filing date: 1988-06-20
Publication date: 1990-02-12
Also published as: CS426988A1

Abstract

Riešenie sa týká spósobu pripravy 2,6 dialkyl-N-(l’-metoxy-2’-propyl)aniIínov, v ktorých alkylové skupiny móžu byť rovnaké alebo rózne a znamenajú metyl alebo etyl, hydrogenačnou alkyláciou příslušných 2,6-dialkylanilínov metoxypropanónom v prostředí 1-metoxy2-propanolu a v přítomnosti trihydrogénfosforečnej kyseliny ako protónového katalyzátora a platinového hydrogenačného katalyzátora. Výsledná reakčná zmes, z ktorej sa připadne najprv oddělí platinový hydrogenačný katalyzátor, sa zbaví rektifikáciou vody vo formě jej azeotropných zmesí s metoxypropanónom a l-metoxy-2-propanoIom, ďalšou rektifikáciou sa z nej oddělí l-metoxy-2-propanol, z heterogénneho destilačného zvyšku sa oddělí horná vrstva reakčného produktu, pričom spódná vrstva, pozostávajúca z disperzie platinového hydrogenačného katalyzátora v protónovom katalyzátore alebo z protónového katalyzátora, zriedená l-metoxy-2-propanolom a připadne doplněná čerstvým platinovým hydrogenačným katalyzátorem a/alebo čerstvým protónovým katalyzátorem a z reakčnej zmesi připadne oddělený platinový hydrogenačný katalyzátor samotný alebo doplněný čerstvým katalyzátorem a l-metoxy-2-propanol sa vracajú do ďalšieho cyklu hydrogenačnej alkylácie. Riešenie je možné využiť v chemickom priemysle pri výrobě chemických prostriedkov na ochranu rastlín.The solution relates to a method of preparing 2,6-dialkyl-N-(1'-methoxy-2'-propyl)anilines, in which the alkyl groups can be the same or different and represent methyl or ethyl, by hydrogenation alkylation of the respective 2,6-dialkylanilines with methoxypropanone in the environment of 1-methoxy-2-propanol and in the presence of trihydrophosphoric acid as a proton catalyst and a platinum hydrogenation catalyst. The resulting reaction mixture, from which the platinum hydrogenation catalyst is separated first, is removed by rectification of water in the form of its azeotropic mixtures with methoxypropanone and 1-methoxy-2-propanol, 1-methoxy-2-propanol is separated from it by further rectification, the upper layer of the reaction product is separated from the heterogeneous distillation residue, while the lower layer, consisting of a dispersion of the platinum hydrogenation catalyst in proton catalyst or from the proton catalyst, diluted with l-methoxy-2-propanol and optionally supplemented with fresh platinum hydrogenation catalyst and/or fresh proton catalyst, and from the reaction mixture the separated platinum hydrogenation catalyst alone or supplemented with fresh catalyst and l-methoxy-2-propanol are returned to the next cycle of hydrogenation alkylation. The solution can be used in the chemical industry in the production of chemical agents for plant protection.

Description

CS 267 385 B1

The invention relates to a process for the preparation of 2,6-dialkyl-N- (1'-methoxy-2'-propyl) anilines. Said compounds are intermediates for the production of chemical plant protection agents.

2,6 dialkyl N (alkoxy-2'-propyl) anilines are known from the patent literature (US 2 387 071, US 2 759 943). Prepare their non-prop. by reacting 2,6-dialkylanilines with 2-halogeno-t-alkoxypropane (US 3,937,730). Their method of preparation is based on the condensation of 2,6-dialkylanilines with alkoxyproponone and the simultaneous or subsequent hydrogenation of 2,6-dialkyl-N- (1'-alkoxy-2'-propylidene) aniline (azomethine) ( US 3,937,730, US 4,022,611). It is also known that such a type of hydrogenation alkylation is carried out in the presence of a proton catalyst and a noble metal hydrogen catalyst (US 4 200 451), in the absence of a solvent (US 4 200 451, DE 2 328 340) or in a solvent medium (BE 810 763, CS 219 856). On the one hand, the proton catalytic catalyst accelerates the condensation reaction of 2,6-dialkylaniline with alkoxypropanone and on the one hand activates the noble metal hydrogenation catalyst in parallel hydrogenation of azomethine. The noble metal hydrogenation catalysts, e.g. palladium or platinum, are deactivated during the hydrogenation by the action of catalysts such as, for example, polymeric polymeric substances, including nitrates, including amines and nucleophiles. It is known from the literature that acetic acid can be used as proton catalyst in the hydrogenation alkylation of 2,6-disubstituted anilines with alkoxypropanones and ethyl alcohol as solvent (CS 219 856). A significant disadvantage of this drawback is that the resulting reaction mixture contains, in addition to the reaction product, a low boiling point component such as acetic acid, ethyl alcohol, water, unreacted methoxypropanone and its hydrogenation-producing 1-methoxy-2-propanol and optionally oc- tan ethyl. Since these components have close boiling points and, in addition, form multiple-octootropic mixtures, it is not possible to efficiently divide them and reuse them, making the process more expensive and causing problems related to the disposal of such wastes.

The above drawbacks are remedied by the \ t

the preparation of 2,6-dialkyl-N- (1'-methoxy-2'-propyl) aniline of formula I CHo

NH 2 -CH-CH 2 O-CH 3

wherein R 1 and R 2 are the same or different and are methyl or ethyl, by hydrogenation alkylation

2,6-dialkylanilines of formula II

wherein R 1 and R 2 are as defined above, methoxypropanone in 1-methoxy-2-propanol and in the presence of phosphoric trihydroxide as the proton catalyst and the platinum hydrogenation catalyst of the invention. It consists in that the resulting reaction mixture, from which the platinum hydrogenation catalyst is first removed, is rectified with water in the form of its azeotropic mixtures with methoxypropanone 1-methoxy-2-propauol, the other rectification is separated therefrom 1- methoxy-2-propanol, the upper layer of the reaction product is separated from the heterogeneous distillation residue, the lower layer consisting of a proton catalyst, optionally from a dispersion of a platinum hydrogenation catalyst in a proton catalyst, diluted 1-methoxy- With 2-propanol and optionally supplemented with fresh proton catalyst and / or fresh platinum hydrogenation catalyst, optionally a separate platinum hydrogenation catalyst alone or with fresh catalyst and 1-methoxy-2- propanol is returned to the next cycle of hydrogenation alkylation.

Trihydrogenphosphoric acid, used as the acroproton catalyst, reacts with the starting 2,6-dialkylaniline to form 2,6-dialkylaniline trihydrogenphosphate. With the progressive hydrogenation alkylation of 2,6-dialkylaniline with methoxy-propanone to 2,6-dialkyl-N- (1'-methoxy-2'-propyllaniline, said salt crosses 2,6-dialkyl-N- (1'-methoxy- 2'-propyl) aniline di- (trihydrogenphosphate), both of which have the properties of a proton catalyst, and thus the resulting reaction mixture consists of 1-methoxy-2-propanol, which is added to the process and the solvent and, in a certain amount, is formed by the side-process. by hydrogenation of methoxypropanone, further from the reaction water used as a solvent, from the excess methoxypro-panone, from 2,6-dialkyl-N- (r -methoxy-2'-propyl) aniline di- (trihydrogenphosphate), from the partially inactivated platinum hydrogenation catalyst on activated carbon as the carrier and from the reaction product corresponding to 2,6-dialkyl-N- (1'-methoxy-2'-propyl) aniline.

In the preparation of 2,6-dialkyl-N- (1'-methoxy-2'-propylanilines of the formula I), the platinumhydrogenation catalyst can be filtered off or settled in an autoclave by the end of the hydrogenation alkylation. The reaction mixture is treated with the fines of the platinumhydrogenation catalyst in the absence of CS 267 385 B and the water is removed from the reaction mixture by removing water in the form of its azeotropic mixture with ineloxypiopanone and 1 meloxy-2 propanol (azeotropic mixture). water with methoxypro-panone contains 40% by weight of water and boils at 93 ° C, the azeotropic mixture of water with 1-methoxy-2-propanol contains 48.5% by weight of water and boils at 96 ° C) and as a further fraction is pure-methoxy- 2-propanol with a boiling point of 119 DEG -121 DEG C. From the heterogeneous distillation residue, the upper layer is evacuated from which the reaction product is obtained by vacuum distillation. 2,6-dialkyl-N-1'-methoxy-2'-propyl) aniline, the latter containing 1-methoxy-2-propanol and residues of unreacted 2,6-dialkylaniline returns to the next cycle of hydrogenation alkylation. The lower layer of the distillation residue, consisting of a proton catalyst or a fine dispersion of small amounts of platinum hydrogenation catalyst and in a proton catalyst, is returned to a further hydrogen alkylation cycle after dilution with 1-methoxy-2-propanol and optional addition of a fresh proton catalyst. The filtered platinum hydrogenation catalyst diluted with 1-methoxy-2-propanol or the suspension, settled in an autoclave or sedimentation vessel, constituting about 2.5% of the total reaction mixture volume, is returned to another cycloalkylation alkylation after optional fresh catalyst addition . From distilled water, methoxypropanone and 1-methoxy-2-propanol, pure 1-methoxy-2-propanol is obtained by rectification under atmospheric pressure. From the process recovered 1-methoxy-2-propanol is returned to the next hydrogenation alkylation solvent cycle, or it is converted to methoxypropanone by catalytic hydrogenation.

Alternatively, after completion of the hydrogenation alkylation, the reaction mixture is pumped from the autoclave to a distillation vessel in the form of an azeotropic mixture as a further fraction of pure 1-methoxy-2-propanol from the topsheet. The distillation residue is subjected to vacuum distillation to give the reaction product and the bottom layer, composed of a mixture of platinum hydrogenation and proton catalysts, is returned to a further hydrogenation alkylation step after dilution with 1-methoxy-2-propanol and optional addition of a fresh platinum hydrogenation or proton catalyst. An important advantage of the process for preparing 2,6-dialkyl-N- (1'-methoxy-2'-propyl) anilines of the formula I according to the invention in comparison with other methods is its high efficiency, especially in terms of the use of a platinum hydrogenation catalyst, a proton catalyst and 1-methoxy-2-propanol as solvent at high yields and purity of the product and disproportionately less evaporation.

The following examples illustrate but do not limit the invention. Example 1 From a reaction mixture prepared by hydrogenation alkylation of 2-methyl-6-ethylaniline with methoxyppropanone consisting of 36.0 g of 2-methyl-6-ethyl-N- (r -methoxy-2'-propyl) aniline, 0.1 g of 2-methyl-6-ethylamino, 2.7 g of methoxypropanone, 49.6 g of 1-methoxy-2-propanol, 3.2 g of water, 1.5 g of 2-methyl-6-ethyl-N- ( 1'-methoxy-2'-propyl) aniline di- (trihydrogenphosphate) was filtered off the used catalyst hydrogenation catalyst to active carbon (80 mg with a platinum content of 5%). Reaction water and unreacted methoxypropanone were removed from the filtrate with a portion of 1-methoxy-2-propanolurectification at 93-118 ° C on the column heads. An additional 1-methoxy-2-propanol was added to a further 118-121 ° C fraction, and further portions of 1-methoxy-2-propanol were distilled off after vacuum was applied. The distillation residue was separated into two layers during rectification. The upper layer was subjected to vacuum de-distillation, with 1-methoxy-2-propanol, 2-methyl-6-ethylaniline and 2-methyl-6-ethyl-N- (1'-methoxy-2'-pro-polyl). ) of aniline returned to the next cycle of hydrogenation alkylation. The main fraction of 2-methyl-6-ethyl-N- (1'-methoxy-2'-propyl) aniline was 34.0 g at 88 ° C / 3.7Pa. 1.5 g was dissolved in 7.5 g of 1-methoxy-2-propanol without cooling and returned to the next round of hydrogenation alkylation. A portion (20%) of the filtered platinum hydrogenation catalyst was separated into regeneration and the remainder after addition fresh catalyst was returned to the next step of hydrogenation alkylation. Example 2

The reaction mixture prepared by hydrogenation of 2-methyl-6-ethylaniline by methoxypropanone of the same composition as in Example 1 was cooled and placed in a sedimentation vessel where it was left to settle for 5 hours. The deposited platinum hydrogenation catalyst was discharged and the upper clear layer was subjected to vacuum distillation. At a pressure of 2.7 kPa and a temperature of up to 100 ° C, volatiles containing water distilled off. methoxypropane and 1-methoxy-2-propanol. The mixture was then partitioned on an atmospheric pressure rectification column with naazeotropic mixtures having a boiling point of 93-118 ° C and anhydrous 1-methoxy-2-propanol with a boiling point of 118-121 ° C. The distillation residue consisting of a mixture of 1-methoxy-2-propanol, 2-methyl-6-ethyl-aniline and a portion of 2-methyl-6-ethyl-N- (1'-methoxy-2'-propyl-aniline) was returned to the next cycle of drug treatment. The lower viscous phase consisting of the proton catalyst and the fine dispersion of the residues of the non-sedimented platinum hydrogenation catalyst was discharged into 1-methoxy-2-propanol, and after the distillation of the volatile fractions the concentrated reaction mixture was separated. the addition of a red proton catalyst was used in the next cycle of hydrogenation alkylation.

Claims

The residue of the distillation residue was subjected to vacuum distillation. First aliquots consisting of 1-nicloxy-2-propanol, 2-methyl-6-ethyl-aniline and 2-inelyl-6-ethyl-N- (1'-methoxy-2'-propyl); the next cycle of hydrogenation alkylation was distilled and 2-methyl-6-ethyl-N- (1'-methoxy-2'-piO-pyljaniline with a boiling point of 129-131 ° C / 1 was distilled as the main extraction) The platinum hydrogenation catalyst used in the sedimentation vessel was used in the next cycle of hydrogenation alkylation. The reaction mixture prepared by hydrogenation of 2-methyl-6-ethylaniline by methoxypropanone of the same composition as in Example 1 was found to be volatile. and the solvent by recrystallization as described in Example 1. The de-distillation residue contained two phases, the upper layer being pumped without vacuum to vacuum distillation to give 2-methyl-6-ethyl-N- (1'-methoxy-2). The lower viscous phase, consisting of the dispersion of a A 5% active carbon hydrotreating catalyst and a 5% platinum-containing carrier in the proton catalyst was dissolved in excess of 1-methoxy-2-propanol at a concentration of 2% and used to replenish the fresh proton and platinum hydrogenation catalysts. Example 4 The reaction mixture prepared by hydrogenation of 2-methyl-6-ethylamino by methoxypropanone of the same composition as in Example 1 was transferred to the sedimentation vessel where the platinum hydrogenation catalyst was allowed to settle. The clear mixture was then decanted and concentrated by distilling off water, methoxypropanone and 1-methoxy-2-propanol. To the distillation residue divided into two phases, 0.75 ml of water was added with stirring and without cooling. PREDMET, the viscous phase of the proton catalyst, went into solution in water, and as the bottom layer, it was discharged and used as an aqueous solution of proton catalyst in the next round of hydrogenation alkylation. The upper layer of the wet reaction product was subjected to distillation. The pre-treatment of the azeolrope water with 2-methyl-6-ethyl-N- (1'-methoxy-2'-propyl) aniline was returned to the next cycle distillation and the major 2-Methyl-6-ethyl-N- (1'-methoxy-2'-propyl) aniline was collected at boiling point 129-131 ° C / 1.33 kPa. Example 5 From the reaction mixture obtained by hydrogenation of 2,6-diethylaniline methoxypropanone, consisting of 253 g of 2,6-diethyl-N- (1'-methoxy-2'-propyl) aniline, 21.7 g of water, 10.0 g 2,6-diethyl-N- (1'-methoxy-2'-propyl) aniline di- (trihydrogen-phosphate), 8.8 g of methoxypropanone and 397 g of 1-methoxy-2-propanol were separated by filtration by filtration. 5 is a platinum-containing 5% gplatin hydrogenation catalyst. From the filtrate, the reaction water was removed from the azeotrope with the methoxypropanone residue and 1-methoxy-2-propanol (65 g) by rectification at 92 to 118 ° C. Further rectification at 118-121 ° C gave 347 g of 1-methoxy-2-propanol. The rectification residue was two layers. The upper layer (258 g) of the saber was subjected to vacuum distillation to give 9.4 g of the pre-fraction with a boiling point of 125 ° C / 1.3 kPa and fraction fractions of 248.6 g of 2,6-diethyl-N- (1'-methoxy-2'-propyl) aniline with a boiling point of 137-142 ° C / 1.3 kPa with a purity of 97.2%, corresponding to 86.8%. The lower layer (10.5 g) consisting of the proton catalyst was dissolved in 120 ml of 1-methoxy-2-propanol and used for a further cycle of hydrogenation alkylation. The filtered platinum hydrogenation catalyst sapo supplemented with 0.2 g of fresh 5% platinum catalyst was used in the next cycle of alkylation alkylation. SUMMARY OF THE INVENTION A method of preparing 2,6-dialkyl-N- (1'-methoxy-2'-propyl-anilines of Formula 1)

CH- nh -CH 2 -O-CH 3 (I) wherein R 1 and R 2 are the same or spit and denote! methyl or ethyl, by hydrogenation alkylation of 2,6-dialkylanilines of formula II

wherein R 1 and R 2 are as defined above, methoxypropanone in 1-methoxy-2-propanol and in the presence of a proton and hydrotreating catalyst, characterized in that trihydrogen phosphate is used as the proton catalyst, the resulting reaction mixture from which first, dividing the platinum hydrogenation catalyst by rectification of the water in the form of its azeotropic mixtures with methoxypropanone and 1-methoxy-2-propanol, the further identification being the 1-methoxy-2-propanol, the heterogeneous-pressure / height the upper layer of the reaction product is separated off, the bottom layer consisting of a proton catalyst, optionally from a dispersion of the platinum hydrogenation catalyst in the proton catalyst, diluted with 1-methoxy-2-propanol and optionally supplemented with a fresh proton catalyst and / or or with a fresh platinum hydrogenation catalyst; D-divided platinum hydrogenation catalyst alone or supplemented with fresh catalyst, and 1-methoxy-2-propanol is returned to another hydrogenation alkylation ring.