U.S. patent application number 10/007014 was filed with the patent office on 2002-05-09 for process for preparing4-aminodiphenylamine.
Invention is credited to Bielefeldt, Dietmar, Casser, Carl, Giera, Henry, Haider, Joachim, Jautelat, Manfred, Laue, Christian, OOms, Pieter, Schelhaas, Michael.
Application Number | 20020055652 10/007014 |
Document ID | / |
Family ID | 7662486 |
Filed Date | 2002-05-09 |
United States Patent
Application |
20020055652 |
Kind Code |
A1 |
Schelhaas, Michael ; et
al. |
May 9, 2002 |
Process for preparing4-aminodiphenylamine
Abstract
The invention provides a process for preparing
4-aminodiphenylamine, an important starting product for
synthesizing antioxidants and stabilizers in the rubber and polymer
industry, by hydrogenating nitrosobenzene with hydrogen in the
presence of a proton acid as catalyst and in the presence of a
hydrogenating catalyst, optionally in the presence of an inert
organic solvent and thermally decomposing the 4-ADPA ammonium salt
produced in this way, wherein 4-ADPA is obtained.
4-aminodiphenylamine is produced in good yields and high purity by
the process according to the present invention. Furthermore, no
effluent is produced, which makes the process particularly economic
and ecological.
Inventors: |
Schelhaas, Michael; (Koln,
DE) ; Casser, Carl; (Berlin, DE) ; Bielefeldt,
Dietmar; (Ratingen, DE) ; OOms, Pieter;
(Krefeld, DE) ; Haider, Joachim; (Koln, DE)
; Jautelat, Manfred; (Burscheid, DE) ; Laue,
Christian; (Monheim, DE) ; Giera, Henry;
(GroBkitzingen, DE) |
Correspondence
Address: |
BAYER CORPORATION
PATENT DEPARTMENT
100 BAYER ROAD
PITTSBURGH
PA
15205
US
|
Family ID: |
7662486 |
Appl. No.: |
10/007014 |
Filed: |
November 6, 2001 |
Current U.S.
Class: |
564/434 |
Current CPC
Class: |
C07C 209/38 20130101;
C07C 209/38 20130101; C07C 211/55 20130101 |
Class at
Publication: |
564/434 |
International
Class: |
C07C 211/55 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 8, 2000 |
DE |
10055221.8 |
Claims
What is claimed is:
1. A process for preparing 4-aminodiphenylamine (4-ADPA),
comprising the step of hydrogenating nitrosobenzene with hydrogen
in the presence of a proton acid as catalyst and in the presence of
a hydrogenation catalyst, optionally in the presence of an inert
organic solvent to form an 4-ADPA ammonium salt which is then
thermally decomposed to obtain 4-ADPA.
2. A process according to claim 1, wherein hydrogenation is
performed at temperatures of -20.degree. C to 50.degree. C and
pressures of 0.1 to 150 bar.
3. A process according to claim 1, wherein the thermal
decomposition of 4-ADPA ammonium salt is performed at temperatures
of 50 to 200.degree. C and pressures of 1013 to 0.05 mbar.
4. A process according to claim 1, wherein said proton acids are
aliphatic and aromatic sulfonic acids, hydrogen fluoride or
trifluoroacetic acid.
5. A process according to claim 1, wherein said organic solvents
are aliphatic or aromatic hydrocarbons, linear or cyclic ethers,
halogenated aliphatic or aromatic hydrocarbons or their mixtures.
Description
FIELD OF THE INVENTION
[0001] The invention provides a process for preparing
4-aminodiphenylamine (4-ADPA), an important starting product for
synthesizing antioxidants and stabilizers in the rubber and polymer
industry (Kirk-Othmer, Encyclopedia of Chemical Technology, 4th
edition, 1992, Vol. A3, pages 424-456; Ullman's Encyclopedia of
Industrial Chemistry, 5th edition, Vol. A3, 1985, pages
91-111).
BACKGROUND OF THE INVENTION
[0002] 4-aminodiphenylamine can be prepared using a variety of
methods. One possibility is the two-step (intermediate product
4-nitrodiphenylamine) reaction of aniline or aniline derivatives
with p-chloronitrobenzene in the presence of an acid acceptor or a
neutralizing agent and optionally in the presence of a catalyst.
Preparation using this method is described, for example, in DE-A 3
501 698, DE-A 1 856 63, U.S. Pat. No. 4,670,595, U.S. Pat. No.
4,187,249 and U.S. Pat. No. 4,187,248. A disadvantage of this
process is that the halide ions being produced have to be disposed
of at considerable cost and the starting materials such as
p-chloronitrobenzene or the corresponding formanilide derivatives
have to be prepared in additional reaction steps.
[0003] Another possibility for preparing 4-ADPA comprises the
reaction of aniline or corresponding aniline derivatives with
nitrobenzene in the presence of tetraalkylammonium hydroxides and
in the presence of regulated amounts of protic material (see WO
95/00324 and WO 93/24250). The disadvantage in this case is the low
thermal stability of tetraalkylammonium hydroxides, so these cannot
be fully recycled to the process.
[0004] The one-step preparation of 4-ADPA from nitrobenzene or
nitrosobenzene in the presence of hydrogen, a hydrogenating
catalyst and in presence of bases provides only unsatisfactory
yields of 4-ADPA (see DE-A 19 70 91 24 and DE-A 19 734 055).
[0005] Another possibility for preparing 4-ADPA comprises the
acid-catalyzed dimerization of nitrosobenzene to
4-nitrosophenyl-diphenyl- hydroxylamine followed by reduction to
4-ADPA (see DE-A 1 147 237 and DE-A 2 703 919). The disadvantage of
this process is the isolation of thermally unstable
4-nitrosophenyl-phenylhydroxylamine which is required and the
effluent optionally produced by neutralization.
SUMMARY OF THE INVENTION
[0006] The present invention provides a process for preparing
4-ADPA which is characterized in that nitrosobenzene is
hydrogenated with hydrogen in the presence of a proton acid as
catalyst and in the presence of a hydrogenation catalyst,
optionally in the presence of an inert organic solvent, and the
4-ADPA ammonium salt thus produced is thermally decomposed, wherein
4-ADPA is produced.
DETAILED DESCRIPTION OF THE INVENTION
[0007] Proton acids which are suitable for the process according to
the present invention are aliphatic and aromatic sulfonic acids
such as methanesulfonic acid and benzenesulfonic acid, hydrogen
fluoride and trifluoroacetic acid. The yield of 4-ADPA generally
decreases with increasing water content of the acids according to
the present invention, so the use of anhydrous acids is preferred.
The acids are preferably used according to the present invention in
amounts of 0.1 to 100, preferably 1 to 100 mol per mol of
nitrosobenzene. The acids may be used either individually or in the
presence of each other.
[0008] Hydrogenation catalysts, which are suitable for the process
according to the present invention are virtually all heterogeneous
catalysts which are known to be hydrogenation catalysts. Catalysts
according to the present invention include metals from the 8th-10th
groups of the Periodic System (according to IUPAC, new) or copper
and/or chromium on suitable supports with a metal content of 0.01
to 50 wt. %, preferably 0.1 to 20 wt. %, with respect to the total
weight of catalyst. According to the present invention, catalysts
may be used which contain one or more of the metals mentioned
above. Preferred metals are platinum, palladium and rhodium, more
preferably, platinum and palladium. Further preferred catalysts are
Raney nickel and supported nickel catalysts. According to the
present invention, the metals mentioned above, or their compounds,
may also be used in the pure form as solids. Palladium black and
platinum black may be mentioned as examples of a metal in the pure
form.
[0009] Catalysts according to the present invention may be used in
amounts of 0.01 to 20 wt. %, with respect to the nitrosobenzene
used, preferably in amounts of 0.01 to 10 wt. %, in batchwise
process variants. When performing the reaction in a continuous
manner, for example in a stirred tank with powdered catalysts or in
the trickle phase on fixed bed catalysts, loads of 0.01 to 500 g of
nitrosobenzene per g of catalyst and per hour are used.
[0010] The reaction temperatures for the process according to the
present invention are -20.degree. C to 50.degree. C, preferably
-10.degree. C to 30.degree. C.; the hydrogen pressure is 0.1 to 150
bar, preferably 0.5 to 70 bar, most preferably 1 to 50 bar.
[0011] The process according to the present invention may also be
performed in the presence of organic solvents. Aprotic solvents,
which are inert to the proton acid used and under the hydrogenation
conditions are preferred. Suitable inert organic aprotic solvents
are aliphatic or aromatic hydrocarbons, linear or cyclic ethers,
halogenated aliphatic or aromatic hydrocarbons or their mixtures.
The following may be mentioned as suitable solvents: benzene,
toluene, xylene, tert.-butyl methyl ether, dioxan, tetrahydrofuran,
chloroform, methylene chloride and/or chlorobenzene. The amount of
solvent used in the process according to the present invention is
not critical. Suitable amounts may also easily be determined by
appropriate preliminary trials. In the case of continuous addition
of nitrosobenzene and catalyst acid, the amount of solvent used
depends in particular on the solubility of nitrosobenzene in the
solvent used.
[0012] The process according to the present invention may be
performed either continuously or batchwise. When using a batchwise
procedure, the proton acid is added to the nitrosobenzene,
optionally in the presence of a solvent, and the reaction mixture
obtained is then hydrogenated with hydrogen in the presence of a
hydrogenation catalyst. Continuous process variants may be
performed in equipment known to a person skilled in the art for
bringing solid, liquid and gas phases into contact. Stirred tanks,
forced circulation reactors, bus reactors, bubble columns operated
in cocurrent or countercurrent mode or trickle phase reactors or
cascades of these reactors are suitable.
[0013] Isolation of the 4-aminodiphenylamine from the acid reaction
mixture is performed in such a way that water is added to the
reaction mixture, the mixture is neutralized with a base and then
optionally extracted with an organic solvent. According to the
present invention, a preferred mode of working-up the reaction
mixture comprises working up the reaction mixture by distillation
after filtering off the hydrogenation catalyst. In this way, the
proton acid used and optionally the solvent used can be virtually
quantitatively recycled. No effluent is produced in the process
according to the present invention, which is of great economic and
ecological advantage.
[0014] The 4-ADPA salt of the corresponding proton acids remaining
is decomposed thermally at temperatures of about 50 to 200.degree.
C and pressures of 1013 to 0.05 bar in order to obtain 4-ADPA.
EXAMPLES
Example 1
[0015] In an autoclave, 21.4 g nitrosobenzene and 1 g Pd/C (5 %)
are added to 100 ml of anhydrous hydrofluoric acid at 0.degree. C.
The reaction mixture is heated to 10.degree. C and then
hydrogenated under a 30 bar pressure of hydrogen. After filtering
off the hydrogenation catalyst, the catalyst acid (hydrofluoric
acid) is distilled off. The 4-ADPA ammonium salt remaining is
decomposed thermally at 200.degree. C and 16 mbar, wherein 17 g of
4-ADPA with a fluoride content of <0.1 % are obtained.
Example 2
[0016] 100 ml of trifluoroacetic acid are used as catalyst acid
using the same procedure as in Example 1. The 4-ADPA ammonium salt
obtained is thermally decomposed at 100.degree. C. and 1 mbar,
wherein 15 g of 4-ADPA are obtained.
[0017] Although the invention has been described in detail in the
foregoing for the purpose of illustration, it is to be understood
that such detail is solely for that purpose and that variations can
be made therein by those skilled in the art without departing from
the spirit and scope of the invention except as it may be limited
by the claims.
* * * * *