Organic compounds -- part of the class 532-570 series – Organic compounds – Four or more ring nitrogens in the bicyclo ring system
Reexamination Certificate
2001-09-25
2003-07-15
McKane, Joseph K. (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Four or more ring nitrogens in the bicyclo ring system
C548S255000, C548S336100, C544S402000, C558S430000
Reexamination Certificate
active
06593473
ABSTRACT:
The present invention relates to an improved process for the preparation of granular N-alkylammoniumacetonitrile salts of the formula I
R
2
R
3
N
+
R
1
—CR
4
R
5
—CN Y
−
(I)
in which
R
1
is a C
1
- to C
24
-alkyl group, which can be interrupted by nonadjacent oxygen atoms or can carry additional hydroxyl groups, a C
4
- to C
24
-cycloalkyl group, a C
7
- to C
24
-alkaryl group or a group of the formula —CR
4
R
5
—CN,
R
2
and R
3
in each case independently of one another have the meaning of R
1
or together are a saturated 4- to 9-membered ring having at least one carbon atom and at least one other heteroatom from the group consisting of oxygen, sulfur and nitrogen,
R
4
and R
5
in each case independently of one another are hydrogen, C
1
- to C
24
-alkyl groups, which can be interrupted by nonadjacent oxygen atoms or can additionally carry hydroxyl groups, C
4
- to C
24
-cycloalkyl groups or C
7
- to C
24
-alkaryl groups, and
Y
−
is a sulfate or hydrogensulfate anion in the corresponding stoichiometric amount,
from an aqueous solution of the compound of the formula II
R
2
R
3
N
+
R
1
—CR
4
R
5
—CN R
6
O—SO
2
—O
−
(II)
in which R
1
to R
5
are as defined above and R
6
is C
1
- to C
4
-alkyl.
N-alkylammoniumacetonitrile salts, such as N-methylmorpholiniumacetonitrile sulfate and hydrogensulfate are needed in particular as activators in the form of solids for low-temperature bleaching in detergents. WO 98/23531 describes granules of such compounds, which can additionally comprise carrier materials, for this application. For the preparation of such sulfate or hydrogensulfate granules, it is recommended to start from the methylsulfate salts.
However, known processes for the preparation of these solid N-alkylammoniumacetonitrile sulfates or hydrogensulfates are still in need of improvement. It is an object of the present invention to provide such a process which avoids the disadvantages of the prior art.
We have found that this object is achieved by the present process, which comprises evaporating the aqueous solution of the compound II at a temperature of from 80° C. to 250° C. and a pressure of from 100 mbar to 2 bar to give a melt, then allowing the melt to solidify, where, during or after the evaporation, customary carrier materials and/or auxiliaries can be added, and the resulting solidified compound I is converted into the desired granular form.
During the evaporation stage, water and also the corresponding C
1
- to C
4
-alcohol which becomes free upon the-partial or complete thermal hydrolysis of the counterion Y are removed from the aqueous solution of the compound II.
The radical R
1
, which has normally arisen as a result of the alkylation of the N atom, is, for example:
a straight-chain or branched relatively long or, in particular, relatively short alkyl radical having from 1 to 24 carbon atoms, where unsaturated radicals, in particular unsaturated fatty acid radicals are also suitable, e.g. methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl, isononyl, decyl, undecyl, dodecyl, tridecyl, isotridecyl, myristyl, cetyl, stearyl or oleyl;
an alkoxyalkyl radical, e.g. methoxymethyl, 2-methoxyethyl, 3-methoxypropyl, 4-methoxybutyl, 2-ethoxyethyl or 3-ethoxypropyl;
a hydroxyalkyl radical, e.g. hydroxymethyl, 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxy-2-butyl or 4-hydroxybutyl;
a radical constructed of repeating C
2
- to C
4
-alkylene oxide units such as ethylene oxide, propylene oxide or butylene oxide, which can be terminated by a hydroxyl group or an alkoxy group, e.g. (C
2
H
4
O)
n
—H or —(C
2
H
4
O)
n
—R
7
, —(C
3
H
6
O)
m
—H or —(C
3
H
6
O)
m
—R
7
, —(C
4
H
8
O)
k
—H or —(C
4
H
8
O)
k
—R
7
n=2 to 11, m=2 to 7, k=2 to 5, R
7
=methyl or ethyl);
a cycloalkyl group such as cyclopentyl, cyclohexyl or cycloheptyl;
an aralkyl group such as benzyl, 2-phenylethyl, 3-phenylpropyl or 4-phenylbutyl;
a group of the formula —CH
2
—CN, —CH(CH
3
)—CN or —C(CH
3
)
2
CN.
Preferred meanings for R
1
are a C
1
- to C
4
-alkyl group or a benzyl radical.
The meanings for the radicals R
4
and R
5
are in principle the same as for R
1
(with the exception of —CR
4
R
5
—CN), and they can additionally also be hydrogen. Preferred meanings for R
4
and R
5
are hydrogen, methyl and ethyl, and in particular both are hydrogen.
In a preferred embodiment, R
1
is a C
1
- to C
4
-alkyl group or a benzyl radical, and R
4
and R
5
are both hydrogen at the same time.
The meanings for the radicals R
2
and R
3
are principally the same as for R
1
for open-chain alicyclic structures. Additionally, R
2
and R
3
can, together with the ammonium N atom, be a saturated heterocyclic ring. Suitable in particular in this connection are those which, apart from the ammonium N atom, contain no, one or two further heteroatoms from the group consisting of oxygen, sulfur and nitrogen, especially from the group consisting of oxygen and nitrogen. Preferred ring sizes are five-, six- and seven-membered rings. Examples of heterocyclic systems which are suitable for this purpose are imidazolidine, 1,2,3-triazolidine and piperazine.
Particular preference is given to systems in which R
2
and R
3
together are a saturated six-membered ring having 5 carbon atoms or having 4 carbon atoms and one oxygen or one nitrogen atom. These are in particular piperidine and morpholine systems.
The radical R
6
is, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl or tert-butyl, preferably methyl.
According to the process of the invention, very particular preference is given to preparing granular N-methylmorpholiniumacetonitrile hydrogensulfate from an aqueous solution of N-methylmorpholiniumacetonitrile methylsulfate.
Depending on the pressure, the evaporation is carried out at temperatures of from 80° C. to 250° C., preferably from 90° C. to 200° C., in particular at from 100° C. to 160° C. In the preferred pressure range, temperatures from 100° C. to 160° C. are particularly favorable because then adequate removal of water and alcohol takes place and the decomposition of the acetonitrile I to the corresponding amide stage is still negligibly slight.
The evaporation is carried out at a pressure of from 10 mbar to 2 bar, preferably from 100 mbar to 1.1 bar, in particular at from 250 to 960 mbar. Preference is given to evaporation under a slight vacuum since under these conditions volatile secondary components can be driven off more easily.
The evaporation step is preferably carried out in a continuous procedure, for example in a Sambay evaporator, a thin-film contact dryer, a falling-film evaporator or a tube-bundle heat exchanger. The evaporation can, however, also be carried out discontinuously, i.e. in a batch process, e.g. in a reactor.
The required residence time for the evaporation step is dependent on the temperature chosen and the pressure chosen and is generally in the range from a few minutes to several hours. A typical range is from 2 minutes to 15 hours, in particular from 5 minutes to 5 hours. In the preferred temperature and pressure range, a residence time of from 5 to 15 minutes is particularly favorable. Residence times which are too long can trigger the decomposition of the product. The residence time distribution should be narrow, in the case of a continuous procedure, the plugflow pattern should be strived for in order to avoid the formation of by products and decomposition products.
In a particularly preferred embodiment, the evaporation is carried out continuously with a residence time of from 5 to 15 minutes.
Leaving the evaporation stage are the product melt and vapors in the form of predominantly water and alcohol vapor. In the process according to the invention, the significant reduction in the input of energy can be achieved by using the condensation of the vapors produced during the evaporation to preheat the aqueous solution of the compound II. As regards apparatus, tube-bundle or plate-type heat exchangers can, for example, be us
Kinder Hans-Jürgen
Mundinger Klaus
Schönherr Michael
Schürmann Gregor
BASF Aktiegesellschaft
McKane Joseph K.
Saeed Kamal
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