Organic compounds -- part of the class 532-570 series – Organic compounds – Amino nitrogen containing
Reexamination Certificate
1999-06-03
2001-03-06
Kumar, Shailendra (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Amino nitrogen containing
C564S469000, C564S492000
Reexamination Certificate
active
06198002
ABSTRACT:
The present invention relates to a process for preparing secondary and tertiary 2-methyl-1,5-pentanediamines of the formula I
where
R
1
and R
2
are H, C
1
-C
20
-alkyl, C
3
-C
8
-cycloalkyl, aryl, C
7
-C
20
-arylalkyl,
where the radicals R
1
and R
2
may bear substituents selected from the group consisting of C
1
-C
20
-alkyl, C
1
-C
20
-alkoxy, C
6
-C
20
-aryloxy and hydroxy, and R
1
and R
2
are not simultaneously hydrogen,
or
R
1
and R
2
are together an unsubstituted or C
1
-C
20
-alkyl- and/or C
1
-C
20
-alkoxy-substituted C
3
-C
7
-alkylene chain which may, if desired, be interrupted by one or two O or NR
3
groups, where
R
3
is H or C
1
-C
20
-alkyl.
The invention further relates to the compound 1,5-bis(dimethylamino)-2-methylpentane.
U.S. Pat. No. 3,673,251 describes a continuous process for preparing secondary and/or tertiary monoamines, diamines or polyamines from mononitriles, dinitriles or polynitriles and primary or secondary amines. In the preparation of N,N,N′,N′-tetraethyl-2-methyl-1,5-pentanediamine (loc. cit., Example 3), a yield of 60% is achieved in a complicated process using 5% palladium on carbon and diatomaceous earth as catalyst with adsorption of the ammonia formed on solid calcium chloride.
WO 95/30666 discloses the self-condensation of three molecules of 2-methylglutarodinitrile in the presence of hydrogen over Pd/Al
2
O
3
catalysts to give 1,5-bis(3-methylpiperidino)-2-methylpentane. However, this process cannot be applied to the preparation of other tertiary or secondary 2-methyl-1,5-pentanediamines. Example 8 of this patent application describes the reaction of excess 3-methylpiperidine with 2-methylglutarodinitrile and hydrogen in the presence of a Pd/Al
2
O
3
catalyst, which gives 1,5-bis(3-methylpiperidino)-2-methylpentane as main product. Before the reaction, the reaction temperature of 180° C. had been set in a very small reactor charged with catalyst (amount of catalyst: 3 g) in a stream of hydrogen under pressure.
WO 96/33986 describes the reaction of 2-methylglutarodinitrile with 3-methylpiperidine and hydrogen over a Pd/Al
2
O
3
catalyst to give a mixture of 2- and 4-methyl-5-(3-methylpiperidino)-pentanenitrile which is hydrogenated in a separate step to form 2- and 4-methyl-5-(3-methylpiperidino)pentane-1-amine. The corresponding tertiary diamine, viz. 1,5-bis(3-methylpiperidino)-2-methylpentane is obtained only as by-product in yields of not more than 24.4% (loc. cit., Example 1). Prior to the reaction, the very small reactor charged with catalyst (amount of catalyst: 3 g) had been heated to the reaction temperature of 150° C. in a stream of hydrogen under pressure.
GB-A-1, 157,637, GB-A-1, 157,638 and GB-A-1, 157,639 disclose the reaction of 2-methylglutarodinitrile with diethylamine in the presence of hydrogen and palladium to give 5-diethylamino-2-methylvaleronitrile. Despite long reaction times and high molar excesses of diethylamine, no N,N,N′,N′-tetraethyl-2-methyl-1,5-pentanediamine was found here.
According to EP-A-673 918, nitriles are reacted with secondary amines and hydrogen in the presence of palladium catalysts to give peralkylated amines. Here, 3-dimethylaminopropionitrile and dimethylamine are reacted to form N,N,N′,N′-tetramethyl-propylene-1,3-diamine, 3-hydroxypropionitrile and dimethylamine are reacted to form 3-dimethylaminopropan-1-ol and piperazine is reacted with acetonitrile to give N-ethylpiperazine.
EP-A-599 180 describes a process for preparing N,N,N′,N′-tetrasubstituted diamines by reaction of dinitriles with secondary amines. Here, adiponitrile is reacted with dimethylamine and hydrogen in the presence of a Pd/Al
2
O
3
-catalyst to give N,N,N′,N′-tetramethylhexamethylenediamine (loc. cit., Examples 1 to 6).
An attempt to apply the process of EP-A-599 180 to the preparation of N,N,N′,N′-2-pentamethylpentane-1,5-diamine from 2-methylglutarodinitrile and dimethylamine gives only unsatisfactory yields.
A dependence of the results of the reaction of nitrites with amines and hydrogen in the presence of catalysts comprising noble metal on the molecular structure of the nitrile used is mentioned in L. Cerveny, Studies in Surface Science and Catalysis, Vol. 27: Catalytic Hydrogenation, page 122, lines 1-4 (Elsevier, 1986).
The earlier German Patent Application No. 197 13 383.5 describes an improved, compared to EP-A-673 918 and EP-A-599 180, process (cf. loc. cit., page 2, lines 1-2) for preparing tertiary amines from nitrites and secondary amines and hydrogen in the presence of a palladium-containing catalyst. In the example, N,N,N′,N′-tetramethylhexamethylenediamine is prepared from adiponitrile and dimethylamine using an improved catalyst comprising palladium and platinum on zirconium dioxide.
L. Cerveny, Studies in Surface Science and Catalysis, Vol. 27: Catalytic Hydrogenation teaches, on page 124, last paragraph, page 125, first paragraph and page 140, Chapter 4.7, lines 10-11, that the nature of the support of the noble metal catalyst in the reaction of nitrites with amines has only a slight effect on the catalyst properties. According to loc. cit., page 122, second-last paragraph, pretreatment of a supported palladium catalyst with hydrogen at 200° C. makes it inactive in the catalytic reaction of nitrites to give primary, secondary or tertiary amines.
It is an object of the invention to find an economical process which allows secondary and tertiary 2-methyl-1,5-pentanediamines to be obtained in good yields and selectivities and at long catalyst operation lives from 2-methylglutarodinitrile and primary or secondary amines.
A further object is the preparation of 1,5-bis(dimethylamino)-2-methylpentane.
We have found that this object is achieved by a process for preparing a secondary or tertiary 2-methyl-1,5-pentanediamine of the formula I
where R
1
and R
2
are as defined at the outset, which comprises reacting 2-methylglutarodinitrile
with a primary or secondary amine of the formula R
1
R
2
NH and hydrogen at from 50 to 250° C. and pressures of from 0.5 to 35 MPa in the presence of an oxidic supported catalyst comprising one or more noble metals which has been treated with hydrogen at from 50 to 300° C. for at least 0.5 hour before use.
We have also found 1,5-bis(dimethylamino)-2-methylpentane.
The radicals R
1
and R
2
independently have the following meanings, where R
1
and R
2
are not simultaneously hydrogen:
hydrogen (H),
C
1
-C
20
-alkyl, preferably C
1
-C
12
-alkyl, for example methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, n-pentyl, iso-pentyl, sec-pentyl, neo-pentyl, 1,2-dimethylpropyl, n-hexyl, iso-hexyl, sec-hexyl, cyclopentylmethyl, n-heptyl, iso-heptyl, cyclohexylmethyl, n-octyl, 2-ethylhexyl, n-nonyl, iso-nonyl, n-decyl, iso-decyl, n-undecyl, n-dodecyl, iso-dodecyl, preferably C
1
-C
4
-alkyl such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl and tert-butyl, particularly preferably methyl,
C
3
-C
8
-cycloalkyl such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl, preferably cyclopentyl, cyclohexyl and cyclooctyl, particularly preferably cyclopentyl and cyclohexyl,
aryl, preferably C
6
-C
20
-aryl, for example phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl, particularly preferably phenyl, 1-naphthyl and 2-naphthyl, very particularly preferably phenyl,
C
7
-C
20
-arylalkyl such as benzyl, 1-phenylethyl, 2-phenylethyl, 1-naphthylmethyl, 2-naphthylmethyl, phenanthrylmethyls, 4-tert-butylphenylmethyl, 1-phenylpropyl, 2-phenylpropyl, 3-phenylpropyl, 1-phenylbutyl, 2-phenylbutyl, 3-phenylbutyl and 4-phenylbutyl, particularly preferably benzyl, 1-phenylethyl and 2-phenylethyl,
where in these cases the radicals R
1
and R
2
may, independently of one another, bear substituents which are inert under the reaction conditions, e.g. C
1
-C
20
-alkyl, C
1
-C
20
-alkoxy, C
6
-C
20
-aryloxy and hydroxy.
The number of such substituents in R
1
and R
2
can be, depending on the type of radical, from 0 to 5, pref
Eller Karsten
Fiege Bernd
Fuchs Eberhard
Rittinger Stefan
BASF - Aktiengesellschaft
Keil & Weinkauf
Kumar Shailendra
LandOfFree
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