Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C253/00—Preparation of carboxylic acid nitriles
  • C07C253/32—Separation; Purification; Stabilisation; Use of additives
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
  • C07C209/44—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of carboxylic acids or esters thereof in presence of ammonia or amines, or by reduction of nitriles, carboxylic acid amides, imines or imino-ethers
  • C07C209/48—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of carboxylic acids or esters thereof in presence of ammonia or amines, or by reduction of nitriles, carboxylic acid amides, imines or imino-ethers by reduction of nitriles
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
  • C07C209/82—Purification; Separation; Stabilisation; Use of additives
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
  • C07C209/82—Purification; Separation; Stabilisation; Use of additives
  • C07C209/86—Separation
• • 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 invention relates to a process for the joint production of hexamethylenediamine and aminocapronitrile.
• It relates more particularly to a process for the simultaneous manufacture of hexamethylenediamine and aminocapronitrile by hemihydrogenation of adiponitrile.
• Hexamethylenediamine and aminocapronitrile are important compounds used especially as monomers or intermediate products in the manufacture of polymers, in particular the manufacture of polyamides.
• Hexamethylenediamine, used in particular for the synthesis of polyamide 6,6 or polyhexamethylene adipamide is generally obtained by complete hydrogenation of the adiponitrile and purification by distillation.
• hexamethylenediamine and aminocapronitrile can be obtained together by controlling the degree of advancement of the hydrogenation of adiponitrile.
• This incomplete hydrogenation step also called hemihydrogenation, may be carried out under a wide variety of conditions.
• EP741873, EP927157, EP1058677, EP876341 describe a hemihydrogenation process implemented in the presence in particular of ammonia and a solvent such as an alcohol.
• EP 1397346 discloses the implementation of a method of hemihydrogenation in the presence of water, a hydrogenation catalyst and a strong base.
• THA tetrahydroazepine
• One of the aims of the present invention is to propose a method for recovering and producing, from the hemihydrogenation medium of adiponitrile, hereinafter referred to as hydrogenate, a crude hexamethylenediamine having a lowest possible concentration of THA for allow the implementation of a purification producing a hexamethylenediamine according to specifications.
• the invention relates to a process for the simultaneous manufacture of hexamethylenediamine and aminocapronitrile by hemihydrogenation of adiponitrile.
• This process comprises a step of separating the hexamethylenediamine from the hydrogenate by distillation of hexamethylenediamine.
• the distillation of hexamethylenediamine is carried out from the hydrogenate containing a free acid and / or an acidic salt of alkali or ammonium.
• the top fraction A recovered at the top of the column of the distillation step of hexamethylenediamine essentially contains crude hexamethylenediamine with a small amount of THA.
• the amount of THA present in crude hexamethylene diamine represents a small proportion of the THA contained in the hydrogenate.
• the presence of H + ions in the hydrogenate makes it possible to limit the amount of THA distilled with hexamethylenediamine, in particular by favoring the formation of "heavy" compounds and thus of maintaining a large part of the THA present in the hydrogenate in the bottom fraction B of said column.
• the amount of acid and / or acidic salt of alkali or ammonium added or present in the hydrogenate is a function of the hemihydrogenation medium.
• the amount of acid added must allow one hand to neutralize the strong base and on the other hand to obtain a concentration of H + ions sufficient to limit the amount of THA distilling with hexamethylenediamine.
• the amount of acid and / or acid addition salt is determined to obtain sufficient H + ion concentration to obtain a small portion of the THA distill with hexamethylene diamine. This concentration will be sufficient if the ratio T defined below is greater than 1.
• the ratio T is determined by the following formula I:
• [A] represents the molar concentration of anion corresponding to the acid or acid salt
• [M] represents the molar concentration of cation corresponding to the present base and the acidic salt
• n a represents the number of charges of the anion A
• n b represents the number of charges of the cation M.
• the ratio T is preferably between 1.01 and 5, advantageously between 1.2 and 3.
• This ratio T can be determined by calculating the amount of acid added in the hydrogenate as a function of the amount of soluble base. in hydrogenate. It is also possible to determine this ratio by determination of the concentration of cation M and that of the anion A associated with the acid added by analysis in particular, by the usual spectrometry methods.
• the acidic alkali salt is preferentially formed in situ by reaction of the acid with the base present in the hydrogenate.
• the suitable acids are, for example, mineral acids such as sulfuric acid, phosphoric acid, phosphorous acid, hydrochloric acid, or organic acid such as, for example, aliphatic, cycloaliphatic, aromatic carboxylic acids. mono or polyfunctional or aliphatic, cycloaliphatic or aromatic sulphonic acids.
• organic acids mention may be made of acetic acid, propionic acid, valeric acid, hexanoic acid, adipic acid, terephthalic acid and glutaric acid.
• succinic acid methylglutaric acid, ethylsuccinic acid, para-toluenesulfonic acid, methanesulfonic acid, fluoromethanesulfonic acid. It is also possible to use acid resins, in particular resins containing sulphonic groups.
• Acidic salts of alkali or ammonium suitable for the invention include acid salts of sodium, potassium or ammonium acids mentioned above.
• sodium hydrogen sulfate, potassium hydrogen sulphate and ammonium hydrogen sulphate may be mentioned.
• sulfuric acid and alkali hydrogensulfates are preferred.
• the head fraction A recovered by distillation of hexamethylenediamine from the hydrogenate is subjected to a further distillation optionally in the presence of a strong base at a concentration described below. allowing the recovery as a top fraction C. compounds having a boiling point lower than that of hexamethylenediamine such as 1,2-diaminocylohexane (DCH) and 2-aminomethylcyclopentylamine (AMCPA).
• the bottom fraction Al is essentially hexamethylenediamine.
• this bottoms fraction Ai is subjected to a new distillation in the presence, optionally, of a strong base such as potash or sodium hydroxide.
• the amount of strong base added in the bottom fraction A] or the top fraction A is determined to obtain a concentration of between 0.01 g / kg of fraction A 1 or A and 1 g / kg of fraction A 1 or A
• the top fraction A 2 is constituted by hexamethylenediamine to a high degree of purity meeting the required specifications especially for use in the manufacture of polymers such as polyamides.
• the C 1 bottoms fraction contains hexamethylenediamine and heavy compounds including HAT derivatives.
• This tail fraction Ci may advantageously be recycled to the hemihydrogenation stage, either in the hemihydrogenation reactor, or at the stage of conditioning the catalyst when it exists.
• the method of the invention thus makes it possible to recover from the hemihydrogenation medium of adiponitrile, hexamethylenediamine at a high degree of purity, in particular with a very low THA content.
• the various distillations described above are carried out in conventional distillation devices such as tray columns, filling columns and the like.
• the temperature and operating pressure conditions of these columns are set by application of the rules and simulation models conventionally used by those skilled in the art.
• the distillations are preferably conducted at a pressure below atmospheric pressure, preferably below 300 mbar, preferably at a pressure of between 10 and 100 mbar.
• the number of trays of each column is also determined according to the degree of separation desired and by application of the rules and models used in the field of distillation. Generally, the columns used have a number of theoretical plates between 10 and
• the bottoms fraction B obtained by distillation of hexamethylenediamine is subjected to a new distillation to recover a Bi head fraction consisting essentially of aminocapronitrile and a D-bottom fraction consisting essentially of adiponitrile and higher boiling compounds including THA derivatives.
• This tail fraction D is subjected to a new distillation to recover in the form of a top fraction D1 adiponitrile and in the form of tail fraction E compounds of high boiling point and the inorganic salts formed by reaction between the acid and the base.
• the top fraction D1 is recycled to the hemihydrogenation step, while the tail fraction E forms an effluent to be removed.
• distillation of hexamethylenediamine these distillations are carried out in distillation columns usually used for the separation of organic compounds of different boiling points.
• the operating and sizing parameters are determined using the rules and models made available to those skilled in the art.
• the operating pressure of the columns is advantageously less than 300 mbar.
• the temperature of the various bottom of the column is advantageously less than or equal to 185 ° C., preferably less than or equal to 180 ° C. vs.
• the method for the simultaneous manufacture of hexamethylenediamine and aminocapronitrile of the invention makes it possible to recover in a simple and economical manner a hexamethylenediamine with a high degree of purity, in particular by distilling it under conditions favoring the maintenance of the THA in the tail fraction B, ie in the fraction containing aminocapronitrile.
• the process of the invention makes it possible to eliminate the heavy products at the distillation stage of the AdN only.
• the hydrogenate has the following weight composition
• the THA concentration in the hydrogenate is 1,100 ppm.
• the hydrogenate is subjected to distillation in an adiabatic distillation column containing 20 physical plates corresponding to 7 theoretical plates.
• the distillation column operates under a pressure of 20 mbar with a top temperature of 125 ° C. and a bottom temperature of 170 ° C. the reflux ratio is equal to 2.
• Head fraction A was analyzed to determine the percentage of total THA present in the hydrogenate before distillation which distilled with hexamethylenediamine. The aminocapronitrile content in the top fraction was also determined

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Polyamides (AREA)

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• 2005
  • 2005-10-18 FR FR0510588A patent/FR2892118B1/fr not_active Expired - Fee Related
• 2006
  • 2006-10-16 WO PCT/FR2006/002320 patent/WO2007045750A1/fr active Application Filing
  • 2006-10-16 UA UAA200805060A patent/UA89271C2/ru unknown
  • 2006-10-16 JP JP2008536077A patent/JP5000659B2/ja not_active Expired - Fee Related
  • 2006-10-16 KR KR1020117003039A patent/KR20110022731A/ko not_active Application Discontinuation
  • 2006-10-16 KR KR1020087009068A patent/KR101144690B1/ko not_active IP Right Cessation
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  • 2006-10-16 EP EP06820217A patent/EP1937628A1/fr not_active Withdrawn
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