U.S. patent application number 11/081092 was filed with the patent office on 2005-10-06 for storage-stable iminodisuccinate solutions.
Invention is credited to Feller, Rolf, Mitschker, Alfred, Moritz, Ralf-Johann, Schmidt, Holger, Wagner, Paul.
Application Number | 20050217816 11/081092 |
Document ID | / |
Family ID | 34934057 |
Filed Date | 2005-10-06 |
United States Patent
Application |
20050217816 |
Kind Code |
A1 |
Mitschker, Alfred ; et
al. |
October 6, 2005 |
Storage-stable iminodisuccinate solutions
Abstract
The present invention relates to a process for the preparation
of storage-stable iminodisuccinate solutions, by subjecting an
aqueous solution of iminodisuccinate having an ammonia content of
less than 20 ppm to thermal treatment at 40 to 120.degree. C. for 5
hours up to 300 days and subsequent distillation at <120.degree.
C.
Inventors: |
Mitschker, Alfred;
(Odenthal, DE) ; Schmidt, Holger; (Dormagen,
DE) ; Moritz, Ralf-Johann; (Neuss, DE) ;
Wagner, Paul; (Dusseldorf, DE) ; Feller, Rolf;
(Mettmann, DE) |
Correspondence
Address: |
LANXESS CORPORATION
111 RIDC PARK WEST DRIVE
PITTSBURGH
PA
15275-1112
US
|
Family ID: |
34934057 |
Appl. No.: |
11/081092 |
Filed: |
March 14, 2005 |
Current U.S.
Class: |
162/158 |
Current CPC
Class: |
C07C 227/40 20130101;
C07C 229/24 20130101; C07C 229/24 20130101; C07C 227/44 20130101;
C07C 227/44 20130101; C07C 227/40 20130101 |
Class at
Publication: |
162/158 |
International
Class: |
D21H 023/00; D21H
021/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 16, 2004 |
DE |
1020040128731 |
Claims
1. Process for the preparation of storage-stable solutions of
iminodisuccinate having an ammonia content of <50 ppm,
characterized in that iminodisuccinate solutions having an ammonia
content greater than 50 ppm are thermally treated at 40 to
120.degree. C. for 5 hours up to 300 days and are then subjected to
a distillation at temperatures <120.degree. C.
2. Process according to claim 1, characterized in that the thermal
treatment is carried out at 80 to 115.degree. C.
3. Use of the storage-stable iminodisuccinate solutions prepared
according to claim 1 for cosmetics, laundry detergents, cleaning
compositions, domestic cleaning, in paper manufacture, in bleaching
processes and in textile treatment.
Description
[0001] The present invention relates to a process for the
preparation of storage-stable iminodisuccinate solutions, by
subjecting an aqueous solution of iminodisuccinate having an
ammonia content of less than 20 ppm to thermal treatment at 40 to
120.degree. C. for 5 hours up to 300 days and subsequent
distillation at <120.degree. C.
[0002] The preparation of iminodisuccinate or iminodisuccinic acid
and salts thereof belong to the prior art.
[0003] According to GB-A 130 6 331, iminodisuccinate is obtained by
reacting the starting materials maleic acid and ammonia at 60 to
155.degree. C.
[0004] According to SU-A 0639863, iminodisuccinate is obtained by
reacting the same starting materials in the presence of alkali
metals at 110-130.degree. C.
[0005] WO-A 98/45251, finally, discloses the synthesis of
iminodisuccinic acid alkali metal salts by reaction of maleic
anhydride, alkali metal hydroxide, NH.sub.3 and water, the reaction
mixture being admixed with further water and, if appropriate,
methanol, and being freed from NH.sub.3 by distillation at 50 to
170.degree. C. and 0.1 to 50 bar.
[0006] A disadvantage of the processes of the prior art is the fact
that the product comprises considerable amounts of ammonia due to
the process. Even the distillation in WO-A 98/45251, which has
complex apparatus requirements, is not able to reduce the ammonia
in the long term, so that the use of iminodisuccinates have
hitherto been possible only under restrictions.
[0007] However, applications such as textile cleaning, domestic
cleaning and cosmetics require a storage-stable iminodisuccinate
free from emissions of NH.sub.3 gas which originate from
decomposition of the iminodisuccinate or of NH.sub.3 production
residues.
[0008] It is an object of the present invention, therefore, to find
a process for the preparation of storage-stable iminodisuccinate
solutions which makes it possible to store iminodisuccinate
solutions for a long period without formation of ammonia and as a
result makes possible the application in the abovementioned
sectors.
[0009] Surprisingly, it has now been found that an iminodisuccinate
solution which has been heated for a plurality of hours then forms
significantly less ammonia than a correspondingly solution which
has not been thermally treated. At the same time, an
iminodisuccinate solution, after the heating, has a higher content
of iminodisuccinate, than before the heating. It is possible as a
result to obtain a product of significantly higher purity and
better odour properties. Although iminodisuccinate is
temperature-sensitive and heating the solution leads to chemical
decomposition with the formation of ammonia, in the context of the
present invention, it has been found that, by specifically metered
supply of heat, higher product quality can be achieved with respect
to stability of the iminodisuccinate solution against progressive
decomposition and ammonia formation.
[0010] The solution, and thus object of the present invention, is a
process for the preparation of a storage-stable solution of
iminodisuccinate having an ammonia content <50 ppm,
characterized in that an iminodisuccinate solution having an
elevated ammonia content is thermally treated at 40 to 120.degree.
C. for 5 hours up to 300 days and is then subjected to a
distillation at temperatures <120.degree. C.
[0011] Thermal treatment in the context of the present invention
means heating a substance, here an iminodisuccinate solution having
elevated ammonia content, for a relatively long period. An elevated
ammonia content in the context of the present invention and as is
present in the product as a result of the iminodisuccinate
syntheses of the abovedescribed prior art, means 50 to 500 ppm. In
particular as a result of storage of iminodisuccinate solutions, as
are obtained according to the processes described in the prior art,
an increase of the ammonia concentration continuously up to values
up to 150 ppm in the course of 200 days may be observed (FIG.
1).
[0012] An iminodisuccinate solution which has been, according to
the invention, thermally treated at 90.degree. C. and then
subjected to a distillation, prepared by the abovementioned
processes of the prior art, has formed only 35 ppm of ammonia after
200 days (FIG. 1).
[0013] The finding that a thermal treatment of the iminodisuccinate
solution leads to better product properties is surprisingly in
contrast to the observation that an iminodisuccinate solution loses
concentration when it is heated.
[0014] Iminodisuccinate solutions in the context of the present
invention are aqueous solutions of iminodisuccinate, preferably 0.1
to 40% strength by weight aqueous solutions, but also mixtures of
these aqueous solutions with organic solvents, for example
alcohols. Alcohols which may be mentioned by way of example are
methanol, ethanol, propanols, butanols.
[0015] The invention preferably relates to a process for the
preparation of storage-stable solutions of iminodisuccinate having
an ammonia content <50 ppm, characterized in that an
iminodisuccinate solution having elevated ammonia content is
thermally treated at 40 to 120.degree. C., particularly preferably
at 80 to 115.degree. C., for 10 to 100 hours, particularly
preferably 15 to 70 hours, and is then subjected to a distillation
at temperatures of 40 to 130.degree. C., particularly preferably at
60 to 120.degree. C.
[0016] A procedure is followed in such a manner that, after
preparation of the iminodisuccinate solution, this is heated to
temperatures of 80 to 120.degree. C. and kept at these temperatures
for 5 to 200 h, with mixing of the solution. This can be performed
continuously or batchwise. In the case of the continuous procedure,
suitable apparatuses can be selected and connected so that the said
residence times at the said temperatures are achieved. For this, in
chemical and thermal process engineering, a number of advantageous
apparatuses and apparatus connections, for example the kettle
cascade, the tubular reactor, heat exchangers equipped with
internals or the cascaded column are known.
[0017] In a subsequent step, the ammonia distillation is then
carried out continuously or batchwise. To carry out this
distillation step, appropriate apparatuses and distillation designs
are known to those skilled in the art.
[0018] By means of this procedure, iminodisuccinate solutions can
be obtained, the ammonia content of which does not exceed 35 ppm
without further post-treatment, even after a time period of several
hundred days (FIG. 1).
[0019] In accordance with the inventive process, storage-stable
iminodisuccinate solutions are obtained having an ammonia content
less than 50 ppm, preferably less than 40 ppm, particularly
preferably less than 20 ppm, even less than 5 ppm!
[0020] Such low ammonia concentration over a period of up to 200
days now allows the use of the storage-stable iminodisuccinate
solutions in cosmetics, laundry detergents, cleaning compositions,
in domestic cleaning, in paper manufacture, in bleaching processes
and in textile treatment.
EXAMPLE
[0021] After preparation of the iminodisuccinate solution (obtained
in accordance with WO-A 98/45251) this was heated in the reaction
kettle to 102.degree. C. and kept at this temperature for 20 hours
with stirring. Ammonia and water were then distilled off overhead
from the solution in a distillation column at atmospheric pressure.
In the course of this, temperatures resulted in the bottom of 105
to 106.degree. C. At the top of the column a temperature of
99.degree. C. was established.
[0022] After the end of the experiment, the ammonia content in the
distilled iminodisuccinate solution was below the limit of
detection of 2 ppm. After 8 weeks, the ammonia content had
increased to 16 ppm.
* * * * *