Rhodia Fiber & Resin Intermediates

Rhodia Operations

Rhodia Polyamide Intermediates

Vincent Boschat

Philippe Leconte

Lionel Sever

Jean-Pierre Brunelle

Didier Letourneur

Jean-Francis Spindler

Patrick Lermusiaux

Bernard Chevaljer

Bernard Darrier

Jean Louis Bobet

Daniel Rochette

Amino compounds are continuously prepared by hydrogenation of nitrile compounds in the presence of a catalyst, and more particularly diamines are prepared by the continuous hydrogenation of dinitrile compounds in the presence of a Raney metal catalyst and in the absence of an alcoholic solvent; the subject process includes extracting a portion of the catalyst present in the reaction medium, the extracted portion of the catalyst is submitted to a regeneration for providing a catalyst having a catalytic activity lower than that of a fresh catalyst but still high and the regenerated catalyst is recycled to the reaction medium together with fresh catalyst according to a predetermined ratio, whereby the consumption of catalyst is reduced per ton of amines produced.

Continuous preparation of amines by nitrile compound hydrogenation

Methods for hydrogenating nitrile functions into amine functions

The invention concerns the hydrogenation in amine function of a nitrile function of a dinitrile to obtain the corresponding aminonitrile. More precisely, the invention concerns the hemihydrogenation of a dinitrile into the corresponding aminonitrile, in a liquid medium, characterized in that it consists in operating in the presence of a Raney nickel or cobalt catalyst containing copper and/or silver and/or gold and in the presence of an alkaline or alkaline-earth metal hydroxide. The hemihydrogenation of adiponitrile provides amino-6 capronitrile, compound which can be easily transformed by cyclization hydrolysis into caprolactam, the starting product for the synthesis of polyamide-6.

Hemihydrogenation method for dinitriles

The invention concerns a method for regenerating a hydrogenation catalyst, and hydrogenation methods carried out with a catalyst comprising at least one regenerated catalyst. More particularly, it concerns a method for regenerating Raney catalysts used in total or partial hydrogenating processes of compounds comprising nitrile functions into amine functions. Said method consists in treating the spent catalyst with a basic solution and optionally in subjecting said catalyst to hydrogenation before stripping to eliminate the impurities present on the catalyst. Thus, the regenerating method enables to recuperate up to 100% of the catalytic activity.

Method for regenerating a hydrogenation catalyst, method for hydrogenating compounds comprising nitrile functions

The present invention relates to a process for the hydrogenation of aliphatic dinitriles at least partly into corresponding aminonitriles. More specifically, the invention consists of a continuous process for the hydrogenation of dinitrile, at least partly into corresponding aminonitrile, in the presence of a hydrogenation catalyst which is not dissolved in the reaction medium, characterized in that it is carried out in apparatus comprising means for the continuous separation of the hydrogenate and of the catalyst in a zone in which the gas-liquid transfer is limited or zero, the said separation and the recycling of the catalyst being carried out in a period of time less than or equal to 30 minutes.

Method for hydrogenating dinitriles

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Cusset, France

Vincent Boschat