Organic compounds -- part of the class 532-570 series – Organic compounds – Nitriles
Reexamination Certificate
2003-05-21
2004-12-07
Powers, Fiona T. (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Nitriles
C564S498000
Reexamination Certificate
active
06828457
ABSTRACT:
The present invention relates to a process for reducing the content of a monounsaturated aliphatic amine (III) in a mixture (IV) containing an aminonitrile (I) or a diamine (II), or mixtures thereof, and the amine (III), wherein
a) the mixture (IV) is reacted with an anionic nucleophile (V),
which contains a nucleophilic atom selected from the group comprising oxygen, nitrogen and sulfur,
which is capable of taking up an H
+
ion to form an acid with a pK
a
ranging from 7 to 11, measured in water at 25° C., and
which has a relative nucleophilicity, measured in methyl perchlorate/methanol at 25° C.,
ranging from 3.4 to 4.7 when oxygen is the nucleophilic atom,
ranging from 4.5 to 5.8 when nitrogen is the nucleophilic atom, and
ranging from 5.5 to 6.8 when sulfur is the nucleophilic atom,
in an amount ranging from 0.01 to 10 mol per mole of amine (III) in the mixture (IV), to give a mixture (VI), and
b) the aminonitrile (I) or the diamine (II), or mixtures thereof, are distilled from the mixture (VI) at a temperature ranging from 50 to 170° C. and a pressure ranging from 0.5 to 100 kPa.
Mixtures containing an aminonitrile or a diamine, or mixtures thereof, and an unsaturated amine—an unsaturated amine being understood in terms of the present invention as meaning a cyclic or linear compound containing at least one carbon-nitrogen double bond or a compound capable of forming at least one carbon-nitrogen double bond, for example by an elimination reaction—are conventionally obtained in the partial hydrogenation of dinitriles to aminonitriles or a mixture of aminonitriles and diamines, or in the complete hydrogenation of dinitriles to diamines.
The partial hydrogenation of adipodinitrile (ADN) with the simultaneous production of hexamethylenediamine (HMD) and 6-aminocapronitrile (ACN), and the complete hydrogenation of ADN to HMD, in the presence of a catalyst based on a metal such as nickel, cobalt, iron, rhodium or ruthenium, is generally known e.g. from K. Weissermel, H.-J. Arpe, Industrielle Organische Chemie (Industrial Organic Chemistry), 3rd edition, VCH Verlagsgesellschaft mbH, Weinheim, 1988, page 266, U.S. Pat. No. 4,601,859, U.S. Pat. No. 2,762,835, U.S. Pat. No. 2,208,598, DE-A 848 654, DE-A 954 416, DE-A 42 35 466, U.S. Pat. No. 3,696,153, DE-A 19500222, WO-A-92/21650 and DE-A-19548289.
The byproducts formed are, inter alia, azepine derivatives such as N-(2-azepano)-1,6-diaminohexane, N-(2-azepano)-6-aminocapronitrile and, in particular, 2-aminoazepan and tetrahydroazepine (THA).
These azepine derivatives, which cause coloration and impair the product properties and are therefore unwanted impurities in the aminonitriles and diamines conventionally used for the manufacture of synthetic fibers or engineering plastics, can be separated from the aminonitriles, diamines or mixtures thereof only at considerable expense.
EP-A-497333 describes the separation of aliphatic aminonitriles or aliphatic diamines from mixtures containing an aliphatic aminonitrile or aliphatic diamine and a cyclic, monounsaturated aliphatic amine by the addition of bases, the base being used in stoichiometric excess relative to the cyclic, monounsaturated aliphatic amine. Bases recommended for this separation are alkali metal hydroxides, alkaline earth metal hydroxides, tetraalkylammonium hydroxide, alkali metal alkoxides and alkaline earth metal alkoxides.
The disadvantage of this process is a simultaneous polymerization of valuable product which leads to an appreciable loss of valuable product and to unwanted deposits in the apparatuses and machines used for carrying out the process.
It is an object of the present invention to provide a process for reducing the content of a monounsaturated aliphatic amine in a mixture containing an aminonitrile or a diamine, or mixtures thereof, and a monounsaturated aliphatic amine, in a technically simple and economic manner which avoids said disadvantages.
We have found that this object is achieved by the process defined at the outset.
Suitable aminonitriles (I) are compounds containing one or more, such as two, three or four, nitrile groups, preferably one nitrile group, especially compounds containing at least one nitrile group which is located adjacent to an aliphatic carbon atom carrying one or two, preferably two, hydrogen atoms, or mixtures of such aminonitriles.
Suitable aminonitriles (I) are compounds containing one or more, such as two, three or four, amino groups, preferably one amino group, especially compounds containing at least one amino group which is located adjacent to an aliphatic carbon atom carrying one or two, preferably two, hydrogen atoms, or mixtures of such aminonitriles. Particularly preferred aminonitriles are those containing a terminal amino group, i.e. an amino group located at the end of an alkyl chain.
The aminonitrile (I) is preferably based on an alkyl skeleton.
In a preferred embodiment, the aminonitrile (I) has from 4 to 12 carbon atoms.
Suitable aminonitriles (I) are preferably selected from the group comprising 4-aminobutyronitrile, 5-aminovaleronitrile, 2-methyl-5-aminovaleronitrile, 6-aminocapronitrile and 12-aminododecanenitrile, especially 6-aminocapronitrile.
Such aminonitriles can be prepared in a manner known per se.
6-Aminocapronitrile can be obtained by the partial catalytic hydrogenation of ADN with a gas containing molecular hydrogen to give mixtures containing HMD and ACN.
Catalysts which can advantageously be used in this hydrogenation are those based on a metal selected from the group comprising ruthenium, rhodium, nickel, cobalt and, preferably, iron, it being possible for the catalysts to contain other elements as promoters. In the case of iron-based catalysts, suitable promoters are especially one or more, such as two, three, four or five, elements selected from the group comprising aluminum, silicon, zirconium, titanium and vanadium.
Such catalysts and the process conditions for said reaction are described for example in WO-A-96/20166, DE-A-19636768 and DE-A-19646436.
Suitable diamines (II) are compounds containing two or more, such as two, three or four, amino groups, preferably two amino groups, especially compounds containing at least two amino groups which are located adjacent to an aliphatic carbon atom carrying one or two, preferably two, hydrogen atoms, and particularly preferably diamines containing terminal amino groups, i.e. amino groups located at the end of an alkyl chain, or mixtures of such diamines.
The diamine (II) is preferably based on an alkyl skeleton.
In a preferred embodiment, the diamine (II) has from 4 to 12 carbon atoms.
Suitable diamines (II) are preferably selected from the group comprising 1,4-diaminobutane, 1,5-diaminopentane, 2-methyl-1,5-diaminopentane, 1,6-diaminohexane (HMD) and 1,12-diaminododecane.
Such diamines can be prepared in manner known per se.
HMD can be obtained by the partial catalytic hydrogenation of ADN with a gas containing molecular hydrogen to give mixtures containing HMD and ACN, or by the complete hydrogenation of ADN with a gas containing molecular hydrogen.
Catalysts which can advantageously be used in this hydrogenation are those based on a metal selected from the group comprising ruthenium, rhodium, nickel, cobalt and, preferably, iron, it being possible for the catalysts to contain other elements as promoters. In the case of iron-based catalysts, suitable promoters are especially one or more, such as two, three, four or five, elements selected from the group comprising aluminium, silicon, zirconium, titanium and vanadium.
Such catalysts and-the process conditions for said reactions can be found for example in the publications already cited above.
Suitable amines (III) are cyclic or linear compounds containing at least one carbon-nitrogen double bond or a compound capable of forming at least one carbon-nitrogen double bond, for example by an elimination reaction, or mixtures of such compounds.
The amine (III) used can advantageously be a compound of the formula
R
1
—(CH
2
)
n
—CH═N—(CH
2
)
m
—R
2
in
Ansmann Andreas
Bassler Peter
Benisch Christoph
Fischer Rolf-Hartmuth
Luyken Hermann
BASF - Aktiengesellschaft
Keil & Weinkauf
Powers Fiona T.
LandOfFree
Method for reducing the content of an unsaturated amine in a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for reducing the content of an unsaturated amine in a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for reducing the content of an unsaturated amine in a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3281260