Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C253/00—Preparation of carboxylic acid nitriles
  • C07C253/30—Preparation of carboxylic acid nitriles by reactions not involving the formation of cyano groups
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C255/00—Carboxylic acid nitriles
  • C07C255/01—Carboxylic acid nitriles having cyano groups bound to acyclic carbon atoms
  • C07C255/24—Carboxylic acid nitriles having cyano groups bound to acyclic carbon atoms containing cyano groups and singly-bound nitrogen atoms, not being further bound to other hetero atoms, bound to the same saturated acyclic carbon skeleton

Definitions

• the present invention relates to the hemihydrogenation of dinitriles to corresponding aminonitriles.
• the hydrogenation of dinitriles is carried out to prepare the corresponding diamines; thus particularly the hydrogenation of adiponitrile leads to hexamethylene diamine, itself one of the two basic compounds for the preparation of polyamide-6,6.
• US Pat. No. 4,389,348 describes a process for the hydrogenation of dinitrile to omega-aminonitrile, with hydrogen, in an aprotic solvent and ammonia medium and in the presence of rhodium deposited on a basic support.
• US Pat. No. 5,151,543 describes a process for the partial hydrogenation of dinitriles to aminonitriles in a solvent in molar excess of at least 2/1 relative to the dinitrile, comprising liquid ammonia or an alkanol containing a mineral base soluble in said alkanol, in the presence of a catalyst of nickel or Raney cobalt type.
• US Patent 5,981,790 relates to a process for the partial hydrogenation of dinitriles to aminonitriles in the presence of a catalyst based on Raney nickel or Raney cobalt in the presence of at least 0.5% by weight of water in the reaction medium containing the products to be hydrogenated and the hydrogenated compounds. The catalyst is used in conjunction with a base.
• patent application WO 00/64862 describes a process for the partial hydrogenation of a dinitrile for the production of aminonitriles in the presence of a hydrogenation catalyst, a liquid ammonia or alkanol solvent and a compound making it possible to improve the selectivity of the reaction to aminonitriles.
• a hydrogenation catalyst e.g., a hydrogenation catalyst, a liquid ammonia or alkanol solvent and a compound making it possible to improve the selectivity of the reaction to aminonitriles.
• production of unwanted by-products remains high.
• One of the objectives of the present invention is to propose a new process for the selective hydrogenation of a single nitrile function of a dinitrile (called in this text hemihydrogenation) so as to predominantly prepare aminonitrile corresponding and only in a minor way the diamine, with minimal formation of by-products.
• the invention relates to a process for the hemihydrogenation of aliphatic dinitriles into corresponding aminonitriles, using hydrogen and in the presence of a hydrogenation catalyst, for example based on nickel, cobalt, Raney nickel. or Raney cobalt optionally comprising a doping element chosen from the elements of groups 3 to 12 of the periodic table of elements according to the IUPAC nomenclature published in HANDBOOK of Chemistry and Physics-80 th edition 1999-2000, and of a mineral base strong derivative of an alkali or alkaline earth metal or of an ammonium.
• a hydrogenation catalyst for example based on nickel, cobalt, Raney nickel. or Raney cobalt optionally comprising a doping element chosen from the elements of groups 3 to 12 of the periodic table of elements according to the IUPAC nomenclature published in HANDBOOK of Chemistry and Physics-80 th edition 1999-2000, and of a mineral base strong derivative of an alkali or alkaline earth metal or of an ammonium.
• the initial hydrogenation medium comprises water with a content of at least 0.5% by weight relative to all of the liquid compounds of said medium, diamine and / or aminonitrile capable of forming from dinitrile to be hydrogenated as well as unprocessed dinitrile, the weight content of all of these three compounds in the medium being between 80% and 99.5%.
• the hemihydrogenation reaction is carried out in the presence of at least one additive increasing the selectivity in aminonitrile compared to that obtained with the system described above without additive, while maintaining the total selectivity in aminonitrile and diamine at a level at least substantially equivalent to that obtained without the additive.
• product selectivity is meant the yield obtained in this product calculated relative to the amount of dinitrile transformed at the end of the reaction.
• This additive is a compound chosen from the group comprising:
• cyanide radical not linked to a carbon atom
• inorganic cyanides organic / inorganic cyanides, complexes or salts of cyanides such as cyanide hydrogen, lithium cyanides, sodium, potassium, copper, complex cyanides K 3 [Fe (CN) 6 ], K 4 [Fe (CN) 4 ], K 3 [Co (CN) 6 ], K 2 [Pt (CN) 6 ], K 4 [Ru (CN) 6 ], ammonium or alkali metal thiocyanides.
• organic / inorganic cyanide mention may be made of tetraalkylammonium cyanides such as tetrabutylammonium cyanide, tetramethylammonium thiocyanide, tetrapropylammonium thiocyanide.
• isonitrile organic compounds suitable for the invention there may be mentioned tert-octyl isonitrile, tert-butyl isonitrile, n-butyl isonitrile, isopropyl isonitrile, benzyl isonitrile, ethyl isonitrile, methyl isonitrile and l 'amyl isonitrile.
• complex coordination compounds mention may be made of complexes comprising as complexing compounds organic compounds comprising carbonyl, phosphine, arsine or mercapto functions linked to the metal.
• suitable metals mention may be made in particular of the metals of groups 7, 8, 9 and 10 of the periodic classification of the elements cited above such as, for example, iron, ruthenium, cobalt, osmium, rhenium, l 'iridium, rhodium.
• tetraalkylonium hydroxide or fluorinated organic compounds mention may be made of tetraalkylammonium, tetraalkylphosphonium comprising hydroxyl groups or fluorine atoms linked to ammonium or phosphonium groups.
• the alkyl radicals are preferably hydrocarbon groups comprising from 1 to 8 carbon atoms. These radicals can be linear or branched.
• tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium, tetrabutylphosphonium are suitable for the invention.
• the weight ratio of the selective agent relative to the weight of catalytic element expressed by weight of metal such as nickel is between 0.001: 1 and 2: 1, advantageously between 0.005: 1 and 1: 1. This ratio varies according to the nature of the selective agent.
• the process of the invention makes it possible to obtain, for conversion rates of dinitrile greater than 70%, a selectivity to aminonitrile greater than 65% and a total selectivity to aminonitrile and diamine greater than 90%.
• the aliphatic dinitriles which can be used in the process of the invention are more particularly the dinitriles of general formula (I):
• R represents an alkylene or alkenylene group, linear or branched, having from 1 to 12 carbon atoms.
• dinitriles of formula (I) are used in which R represents an alkylene radical, linear or branched having from 2 to 6 carbon atoms.
• Examples of such dinitriles include adiponitrile (AdN), methylglutaronitrile, ethylsuccinonitrile, malononitrile, succinonitrile, glutaronitrile and mixtures thereof, in particular mixtures of adiponitrile and / or methylglutaronitrile and / or ethylsuccinonitrile capable of coming from the same process for the synthesis of adiponitrile.
• AdN adiponitrile
• methylglutaronitrile ethylsuccinonitrile
• malononitrile succinonitrile
• glutaronitrile and mixtures thereof, in particular mixtures of adiponitrile and / or methylglutaronitrile and / or ethylsuccinonitrile capable of coming from the same process for the synthesis of adiponitrile.
• the strong mineral base is generally constituted by hydroxides, carbonates and alkanolates of alkali metal or alkaline earth metal or ammonium. It is preferably chosen from hydroxides, carbonates and alkanolates of alkali metal.
• the strong mineral base used is chosen from the following compounds: LiOH, NaOH, KOH, RbOH, CsOH and their mixtures.
• Water is usually present in the reaction medium in an amount less than or equal to 20% by weight.
• the water content of the reaction medium is between 2% and 15% by weight relative to all of the liquid constituents of said medium.
• the total concentration of targeted aminonitrile and / or of the corresponding diamine and of the unconverted dinitrile in the reaction medium is generally between
• the amount of strong mineral base is advantageously greater than or equal to 0.05 mol / kg of catalyst.
• it is between 0.1 mol and 3 mol per kg of catalyst and more preferably still between 0.15 and 2 mol / kg of catalyst.
• the catalyst used in the process can be nickel, cobalt, Raney nickel or Raney cobalt.
• Raney metals comprise, in addition to nickel or cobalt and the residual amounts of metal removed from the original alloy during the preparation of the catalyst, that is to say generally aluminum, one or more other elements, often called dopants, such as for example chromium, titanium, molybdenum, tungsten, iron, zinc, copper, rhodium, iridium, cobalt and nickel.
• dopants such as for example chromium, titanium, molybdenum, tungsten, iron, zinc, copper, rhodium, iridium, cobalt and nickel.
• dopants chromium and / or iron and / or titanium are considered to be the most advantageous.
• These dopants usually represent, by weight per weight of nickel, from 0% to 10% and preferably from 0% to 5%. These dopants are also used with catalysts based on nickel and / or cobalt.
• the amount of catalyst used can vary widely depending in particular on the operating mode adopted or the reaction conditions chosen. As an indication, it is possible to use from 0.5% to 50% by weight of catalyst relative to the total weight of the reaction medium and most often from 1% to 35%.
• the catalyst is preconditioned before its introduction into the hemihydrogenation medium. This preconditioning is advantageously carried out according to the method described in the Unpublished French patent application No. 00 02997. This process briefly consists in mixing the hydrogenation catalyst, with a determined quantity of strong mineral base and a solvent in which the strong mineral base is sparingly soluble.
• the medium containing the catalyst thus conditioned is fed into the hydrogenation reactor, the hydrogenation reaction being carried out according to the usual conditions and procedures and already described in the literature.
• the selective agent can be added to the reaction medium separately from the catalyst.
• the selective agent is added to the catalyst before the introduction thereof into the reaction medium, for example in the conditioning step thereof.
• the optimum selectivity for aminonitrile, at a constant dinitrile conversion rate, depends on the nature and the dopant content, the amount of water in the reaction medium and the temperature and the nature and base content. and / or selective agent.
• the process of the invention is generally carried out at a reaction temperature less than or equal to 150 ° C., preferably less than or equal to 120 ° C. and, more preferably still, less than or equal to 100 ° C.
• this temperature is between room temperature (around 20 ° C) and 100 ° C.
• the reaction vessel is brought to a suitable hydrogen pressure, that is to say, in practice, between 1 bar (0.10 MPa) and 100 bar (10 MPa) and preferably between 5 bar (0.5 MPa) and 50 bar (5 MPa).
• the reaction time is variable depending on the reaction conditions and the catalyst.
• a discontinuous mode of operation In a discontinuous mode of operation, it can vary from a few minutes to several hours.
• Example 1 is reproduced, but loading the following reagents:

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• 2001
  • 2001-06-22 FR FR0108245A patent/FR2826364B1/fr not_active Expired - Fee Related
• 2002
  • 2002-06-13 MX MXPA03011645A patent/MXPA03011645A/es not_active Application Discontinuation
  • 2002-06-13 WO PCT/FR2002/002023 patent/WO2003000651A2/fr active Application Filing
  • 2002-06-13 SK SK1595-2003A patent/SK15952003A3/sk unknown
  • 2002-06-13 US US10/481,028 patent/US20040204603A1/en not_active Abandoned
  • 2002-06-13 UA UA20031211970A patent/UA75406C2/uk unknown
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  • 2002-06-13 HU HU0400363A patent/HUP0400363A3/hu unknown
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  • 2002-06-13 BR BR0211014-8A patent/BR0211014A/pt not_active IP Right Cessation
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  • 2002-06-13 JP JP2003507058A patent/JP2004530719A/ja active Pending
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  • 2002-06-13 EP EP02780841A patent/EP1397346A2/fr not_active Withdrawn
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