Field of the Invention
The present invention relates to novel chlorinated and brominated diethyltoluenedi¬
amines which are suitable as chain extenders or curing agents for polyurethanes and
as hardeners for epoxy resins. It further relates to the use of these novel compounds
as chain extenders and curing agents for polyurethanes and hardeners for epoxy
resins and to processes for the preparation of said halogenated diethyltoluenediamines
and novel intermediates in said processes.
Background of the Invention
The use of chain extenders and curing agents for the preparation of polyurethanes and
of hardeners for epoxy resins is well known in the art. Polyurethanes, for example, may
be obtained by reacting compounds having H-reactive groups such as polyether
polyols or polyester polyols with a diisocyanate to form a prepolymer which, in a
second step, is then reacted with a curing agent to form the polyurethane. Epoxy
resins, on the other hand, may be obtained by reacting epichlorohydrin with an alcohol
or phenol to obtain a glycidyl derivative which then is reacted with a hardener to obtain
the cured epoxy resin.
The structure of the curing agents and the reactivity of their functional groups are often
used to modify the properties of the final product or to control the reaction rate of the
polymer formation and the processability of the polymer.
Commonly used chain extenders and curing agents for the preparation of poly¬
urethanes (PU) and epoxy resins are aromatic diamines such as alkyl-substituted
and/or chlorinated phenylenediamines or 4,4'-methylene-bisanilines. In the preparation
of polyurethanes, the amino groups of these diamines will react with isocyanato groups
to give urea moieties. The effect of such compounds on the properties of the polymer
system substantially depends on the nature and positions of the alkyl substituents
and/or the number and/or positions of the chlorine atoms on the aromatic rings.
Sterically hindered diamines such as 4,4'-methylenebis-(3-chloro-2,6-diethylaniline)
(M-CDEA) and 4,4'-methylenebis-(2,6-diethylaniline) (M-DEA) are often used as a
curing agent. These compounds, however, do not allow easy processing, as their
melting point is relatively high. Other well known compounds, such as 4,4'-methylenebis-(
2-chloroaniline) (MOCA) or 3,5-bis(methylthio)toluenediamines (E-300) are toxic
and/or malodorous.
It has been an object of the present invention to provide novel aromatic diamines
having low toxicity and no offensive odor, combined with moderate reactivity resulting
in a convenient gel time (or pot life) when mixed with the urethane prepolymers or
epoxy resins. The diamines should also be liquid or semi-liquid at room temperature,
or at least easily soluble in the (uncured) epoxy resins, isocyanates and diols used as
starting materials in the production of cured epoxy resins and polyurethanes.
Summary of the Invention
It has been found that halogenated diethyltoluenediamines of formula
wherein either R is an amino group and R2 is chlorine or bromine, or R2 is an amino
group and R is chlorine or bromine, and isomeric mixtures thereof are liquid or semiliquid
at room temperature and easily miscible with, or soluble in, the starting materials
and prepolymers typically used in the production of polyurethanes and epoxy resins.
They further exhibit convenient gel times and are non-malodorous and less toxic than
e.g. MOCA. They can be easily synthesized in good yields from commercially available
diethyltoluenediamines, either by direct chlorination in sulfuric acid or by bromination of
the corresponding diacetyl derivatives, followed by hydrolytic cleavage of the acetyl
groups. The brominated diacetyl compounds are novel and also an object of the
invention.
Detailed Description of the invention
The invention provides halogenated diethyltoluenediamines of formula
wherein either R is an amino group and R2 is chlorine or bromine or R2 is an amino
group and R1 is chlorine or bromine, as well as isomeric mixtures thereof. Isomeric
mixtures are preferably those which are obtainable from the commercially available
diethyltoluenediamine mixtures, which consist of e.g. about 80% 3,5-diethyltoluene-
2,4-diamine and about 20% 3,5-diethyltoluene-2,6-diamine.
According to one preferred embodiment, the halogenated diethyltoluenediamines of
formula I are chlorinated, which means that either R is an amino group and R2 is
chlorine or R2 is an amino group and R is chlorine.
According to another preferred embodiment, the halogenated diethyltoluenediamines
of formula I are brominated, which means that either R1 is an amino group and R2 is
bromine or R2 is an amino group and R is bromine, or an isomeric mixture thereof.
Another object of the invention is the use of the halogenated diethyltoluenediamines as
chain extenders or curing agents in the production of polyurethanes. Said use is equi¬
valent with a process for the production of a polyurethane by reacting at least one dior
polyfunctional isocyanate with at least one diol or polyol in the presence of, or fol¬
lowed by addition of, at least one of the halogenated diethyltoluenediamines according
to the invention.
Still another object of the invention is the use of the halogenated diethyltoluenedi¬
amines according to the invention as hardeners (curing agents) for epoxy resins. Said
use is equivalent with a process for the production of a cured epoxy resin by reacting
at least one di- or polyfunctional epoxide with at least one of the halogenated diethyl¬
toluenediamines according to the invention.
For both applications the pure isomers or isomeric mixtures of the halogenated
diethyltoluenediamines of the invention may be used alone or in combination with other
amines or mixtures of other amines.
Another object of the invention is a process for the preparation of chlorinated diethyl¬
toluenediamines of formula I , wherein either R is an amino group and R2 is chlorine or
R2 is an amino group and R is chlorine, or isomeric mixtures thereof, comprising the
step of reacting a diethyltoluenediamine of formula
wherein either R1' is an amino group and R2' is hydrogen, or R2' is an amino group and
R ' is hydrogen, or an isomeric mixture thereof, with elemental chlorine in sulfuric acid.
The diethyltoluenediamine starting materials of formula I I can be used as pure isomers,
the preparation of which is disclosed in US 3 275 690, or as an isomeric mixture. Iso¬
meric mixtures are commercially available, for example from Lonza Ltd., Switzerland,
under the designation Lonzacure™ DETDA 80 (isomeric mixture of ca. 80% 2,4-diamino-
3,5-diethyltoluene and ca. 20% 2,6-diamino-3,5-diethyltoluene).
The chlorination typically takes place without addition of a catalyst other than sulfuric
acid.
In a preferred embodiment of the process for the preparation of chlorinated diethyltoluenediamines
of formula I the sulfuric acid is present in an amount of 5 to 50 molar
equivalents, based on the amount of diethyltoluenediamine (II).
In another preferred embodiment of the process for the preparation of chlorinated
diethyltoluenediamines of formula I the chlorine is added in an amount of 2 to 10 molar
equivalents, based on the amount of diethyltoluenediamine (II).
In still another preferred embodiment of the process for the preparation of chlorinated
diethyltoluenediamines of formula I the reaction temperature is between 15 °C and
80 °C. More preferably, the reaction temperature is between 20 °C and 60 °C, for
example at about 40 °C.
Since the chlorination is carried out with elemental chlorine that is gaseous at the
reaction temperature, the reaction is advantageously carried out in a closed vessel,
such as an autoclave made of a chlorine-resistant material.
In sulfuric acid the diethyltoluenediamine starting materials of formula II as well as the
chlorinated products of formula I are present in protonated form as hydrogensulfates
and/or sulfates. During work-up the reaction mixture is neutralized, for example by
addition of a strong base such as sodium hydroxide, to obtain the free chlorinated
diamines of formula I .
A further object of the invention is a process for the preparation of brominated diethyltoluenediamines
of formula I, wherein either R1 is an amino group and R2 is bromine or
R2 is an amino group and R is bromine, or isomeric mixtures thereof, comprising the
steps of
(i) reacting a diethyltoluenediamine of formula
wherein either R is an amino group and R2' is hydrogen, or R2' is an amino group
and R ' is hydrogen,
or an isomeric mixture thereof,
with an acetylating agent to obtain a diacetyl compound of formula
wherein either R " is an acetylamino group and R2" is hydrogen or R2" is an
acetylamino group and R1" is hydrogen,
or an isomeric mixture thereof,
(ii) brominating said diacetyl compound (III) with hydrobromic acid and hydrogen
peroxide to obtain a corresponding brominated diacetyl compound of formula
wherein either R "' is an acetylamino group and R2"' is bromine or R2"' is an acetylamino
group and R "' is bromine,
or an isomeric mixture thereof, and
(iii) hydrolyzing said brominated diacetyl compound (IV) to obtain the corresponding
brominated diethyltoluenediamine (I).
The acetylating agent in step (i) may be any acetylating agent known in the art, for
example acetic anhydride or an acetyl halide. In a preferred embodiment of the
process for the preparation of brominated diethyltoluenediamines of formula I the
acetylating agent in step (i) is acetyl chloride in the presence of triethylamine.
The bromination in step (ii) can take place under relatively mild conditions. In a pre¬
ferred embodiment of the process for the preparation of brominated diethyltoluene¬
diamines of formula I the bromination step (ii) is conducted at a temperature of -10 to
+20 °C.
The hydrolysis step (iii) can be conducted under acidic or basic conditions by adding
either a strong acid or a strong base. In a preferred embodiment of the process for the
preparation of brominated diethyltoluenediamines of formula I the hydrolysis step (iii) is
conducted with hydrochloric acid in methanol, thus yielding the corresponding hydro¬
chlorides which are then neutralized by addition of a base to yield the free diamines.
The brominated diacet l compounds of formula
wherein either R " is an acetylamino group and R2'" is bromine or R2"' is an acetylamino
group and R '" is bromine, or isomeric mixtures thereof, are novel and are likewise an
object of the invention.
The following examples, which however are not intended to limit the scope of the
invention, will illustrate in more detail selected embodiments and preferred modes of
carrying out the invention.
The conversion rates and the product purities were determined by gas chromato¬
graphy (GC) under the following conditions:
Dimethylpolysiloxane (0.35 mih) column, 30 m * 0.32 mm
Temperature program: Starting temperature 130 °C, heating rate 1 K/min up to 145 °C,
then 15 K/min up to 190 °C, finally 30 K/min up to 250 °C.
Sample preparation: Samples of 0.2 g were dissolved in 1 mL of toluene.
Example 1
6-Chloro-3,5-diethyltoluene-2,4-diamine and 4-chloro-3,5-diethyltoluene-2,6-diamine
Lonzacure™ DETDA 80 (isomeric mixture of 80% 3,5-diethyltoluene-2,4-diamine and
20% 3,5-diethyltoluene-2,6-diamine) (3.4 g, 18.6 mmol) and 96 wt% sulfuric acid
(28.5 g, 279 mmol) were introduced in an autoclave made of Hastelloy® HC22. The
autoclave was heated to 40 °C and flushed with nitrogen. After having released the
nitrogen, chlorine gas (5.3 g, 74.4 mmol) was introduced to the mixture. The reaction
was stirred at 40 °C for 18 h (reaction time) and then poured onto ice (50 g). The
suspension was neutralized with 10% aqueous sodium hydroxide solution (230 g) and
after phase separation the aqueous phase was extracted with dichloromethane
(50 mL). The combined organic phases were dried over magnesium sulfate and the
solvent was evaporated under reduced pressure to give 4.5 g of the isomeric mixture I
(R1 = CI, 2 = NH2, and R = NH2, R2 = CI). By GC analysis 96 area% was measured
for the isomeric mixture consisting of 6-chloro-3,5-diethyltoluene-2,4-diamine and
4-chloro-3,5-diethyltoluene-2,6-diamine in a 4:1 ratio.
Yield: 3.7 g (93%)
GC retention time data:
= 12.0 min (3,5-diethyltoluene-2,4-diamine), 13.3 min (3,5-diethyltoluene-2,6-diamine),
18.3 min (6-chloro-3,5-diethyltoluene-2,4-diamine), 18.4 min (4-chloro-3,5-diethyltoluene-
2,6-diamine).
Example 2
6-Chloro-3,5-diethyltoluene-2,4-diamine
Example 1 was repeated using pure 3,5-diethyltoluene-2,4-diamine (prepared accord¬
ing to US 3 275 690) instead of Lonzacure™ DETDA 80.
Yield: 3.5 g (88%)
H NMR (DMSO-de, 500 MHz, 30 °C): d 4.48 (br. s, 4H), 2.57 (q, J = 7.4 Hz, 2H),
2.42 (q, J = 7.4 Hz, 2H), 2.06 (s, 3H), 0.99 (t, J = 7.4 Hz, 3H), 0.98 (t, J = 7.4 Hz, 3H).
3C NMR (DMSO-de, 125 MHz, 30 °C): d 142.38, 141 .63, 131 .20, 113.92, 110.46,
107.77, 2 1.42, 17.96, 14.43, 12.98, 11.90.
Example 3
4-Chloro-3,5-diethyltoluene-2 6-diamine
Example 1 was repeated using pure 3,5-diethyltoluene-2,6-diamine (prepared accord¬
ing to US 3 275 690) instead of Lonzacure™ DETDA 80.
Yield: 3.6 g (90%)
H NMR (DMSO-de, 500 MHz, 30 °C): d 4.48 (br. s, 4H), 2.56 (q, J = 7.4 Hz, 4H),
1.87 (s, 3H), 0.99 (t, J = 7.4 Hz, 6H).
3C NMR (DMSO-de, 125 MHz, 30 °C): d 142.25, 130.80, 113.88, 104.50, 2 1.33,
12.98, 11.33.
Example 4
A^AT-Diacetyl-S.S-diethyltoluene^^-diamine and /V,/V'-diacetyl-3,5-diethyltoluene-2,6-
diamine
A 2 L three necked round bottomed flask was charged with Lonzacure™ DETDA 80
(120 g, 0.67 mol), triethylamine (179 g, 1.77 mol) and dichloromethane (550 mL). The
mixture was cooled to 0 °C and then acetyl chloride (127 g, 1.62 mol) was added
dropwise. The mixture was stirred at room temperature for 3.5 h and then it was
filtered off and the solid washed with water (3 * 100 mL). After drying the solid under
vacuum, 107 g (61%) of isomeric mixture III (R = acetylamino, R2" = H, and R = H,
R2" = acetylamino) were obtained.
Example 5
/v;/V'-Diacetyl-3,5-diethyltoluene-2,6-diamine
Example 4 was repeated using pure 3,5-diethyltoluene-2,6-diamine (prepared accord¬
ing to US 3 275 690) instead of Lonzacure™ DETDA 80.
Yield: 105 g (60%)
H NMR (DMSO-de, 500 MHz, 30 °C): d 9.17 (br. s, 2H), 6.92 (s, 1H), 2.46 (q,
J = 7.4 Hz, 4H), 2.01 (s, 6H), 1.95 (s, 3H), 1.08 (t, J = 7.4 Hz, 6H).
3C NMR (DMSO-de, 125 MHz, 30 °C): d 168.21 , 139.40, 133.65, 132.73, 125.12,
24.38, 22.40, 14.48, 13.49.
Example 6
A^yV-Diacetyl-S.S-diethyltoluene^^-diamine
Example 4 was repeated using pure 3,5-diethyltoluene-2,4-diamine (prepared accord¬
ing to US 3 275 690) instead of Lonzacure™ DETDA 80.
Yield: 111 g (62%)
H NMR (DMSO-de, 500 MHz, 30 °C): d 9.17 (br. s, 2H), 6.93 (s, 1H), 2.42 (m, 4H),
2.07 (s, 3H), 2.01 (s, 6H), 1.09 (t, J = 7.4 Hz, 3H), 0.93 (t, J = 7.4 Hz, 3H).
3C NMR (DMSO-de, 125 MHz, 30 °C): d 168.67, 168.31 , 139.93, 139.27, 134.52,
132.96, 132.29, 126.98, 24.18, 22.40, 20.84, 17.91 , 14.40, 13.87.
Example 7
/^/V-Diacetyl-e-bromo-S.S-diethyltoluene^^-diamine and A/,/VkJiacetyl-4-bromo-
3,5-diethyltoluene-2,6-diamine
Aqueous hydrobromic acid (40 wt% HBr, 493 g, 2.44 mol) was added dropwise to a
solution of isomeric mixture of III (prepared according to Example 4) (40 g, 0.15 mol) in
methanol (650 ml ) at 0 °C. Aqueous hydrogen peroxide (30 wt% H2O2, 259 g,
2.29 mol) was then added at 0 °C and the reaction mixture was allowed to warm up to
room temperature overnight. The yellow reaction mixture was quenched with saturated
aqueous NaHSO3, filtered off and washed with water. The solid was dried under
vacuum to give 4 1 g (79%) of isomeric mixture IV (R "' = acetylamino, R2"' = Br, and
R "= Br, R2"' = acetylamino).
Example 8
/V,yV-Diacetyl-6-bromo-3,5-diethyltoluene-2,4-diamine
Example 7 was repeated using A/^diacetyl-S^-diethyltoluene^^-diamine (prepared
according to Example 6) instead of isomeric mixture III.
Yield: 46 g (62%)
H NMR (DMSO-de, 500 MHz, 80 °C): d 9.17 (br. s, 2H), 2.70 (br. m, 2H), 2.42 (br. m,
2H), 2.22 (s, 3H), 2.03 (s, 6H), 1.07 (t, J = 7.5 Hz, 3H), 0.95 (t, J = 7.5 Hz, 3H).
3C NMR (DMSO-de, 125 MHz, 30 °C): d 169.03, 140.30, 139.68, 135.37, 134.02,
133.39, 123.88, 26.20, 22.36, 2 1.18, 19.55, 13.52, 13.02.
Example 9
yV,yV-Diacetyl-4-bromo-3,5-diethyltoluene-2,6-diamine
Example 7 was repeated using yV,/V-diacetyl-3,5-diethyltoluene-2,6-diamine (prepared
according to Example 5) instead of isomeric mixture III.
Yield: 43 g (60%)
H NMR (DMSO-de, 500 MHz, 80 °C): d 9.17 (br. s, 2H), 2.70 (br. m, 4H), 2.01 (s,
6H), 1.91 (s, 3H), 1.06 (t, J = 7.4 Hz, 3H).
13C NMR (DMSO-de, 125 MHz, 30 °C): d 168.55, 139.98, 134.71 , 134.02, 122.72,
26.15, 22.32, 13.65, 13.09.
Example 10
e-Bromo-S.S-diethyltoluene^^-diamine and 4-bromo-3,5-diethyltoluene-2,6-diamine
The isomeric mixture IV (prepared according to Example 7) (30 g , 0.09 mol), methanol
(250 ml_) and concentrated hydrochloric acid (360 ml_) were charged into a flask and
the mixture was heated at reflux for 120 h. After cooling to room temperature, the
mixture was concentrated under vacuum. Water was added to dissolve the solid, the
pH was adjusted to ~9 with aqueous sodium hydroxide and the product was extracted
with dichloromethane. The organic layer was concentrated and the crude product was
purified by flash column chromatography to give 15 g (65%) of isomeric mixture of I
( = NH2, R2 = Br, and R = Br, = NH2) .
H NMR (DMSO-de, 500 MHz, 30 °C): d 4.39 (br. s, 4H), 2.67-2.62 (m, -2.4H),
2.44-2.40 (m, 1.6H), 2.13 (s, -2.4H), 1.85 (s, -0.6H), 1.00-0.97 (m, 6H).
Example 11
6-Bromo-3,5-diethyltoluene-2,4-diamine
Example 10 was repeated using /V,/V-diacetyl-3,5-diethyltoluene-2,4-diamine (pre¬
pared according to Example 8) instead of the isomeric mixture of IV.
Yield: 14 g (61 %)
H NMR (DMSO-de, 500 MHz, 30 °C): d 4.38 (br. s, 4H), 2.65 (q, J = 7.4 Hz, 2H),
2.44 (q, J = 7.4 Hz, 2H), 2.13 (s, 3H), 0.99 (t, J = 7.4 Hz, 3H), 0.98 (t, J =7.4 Hz, 3H).
13C NMR (DMSO-de, 125 MHz, 30 °C): d 142.60, 141 .84, 125.38, 115.38, 110.94,
109.42, 24.60, 18.03, 17.92, 12.88, 11.77.
Example 12
4-Bromo-3,5-diethyltoluene-2,6-diamine
Example 10 was repeated using /V,/V-diacetyl-3,5-diethyltoluene-2,6-diamine (pre¬
pared according to Example 9) instead of the isomeric mixture of IV.
Yield: 12.5 g (54%)
H NMR (DMSO-de, 500 MHz, 30 °C): d 4.48 (br. s, 4H), 2.64 (q, J = 7. Hz, 4H),
1.86 (s, 3H), 0.99 (t, J = 7.4 Hz, 6H).
13C NMR (DMSO-de, 125 MHz, 30 °C): d 142.50, 124.82, 115.28, 104.96, 24.50,
12.88, 11.36.
Use of the halogenated diethyltoluenediamines as chain extenders and curing agents
for polyurethanes and as hardeners for epoxy resins:
Abbreviations:
DETDA = 3,5-Diethyltoluenediamines (mixture of 80% 2,4- and 20% 2,6-diamine)
DETDA-CI = Chloro-3,5-diethyltoluenediamines (prepared according to Example 1)
DETDA-Br = Bromo-3,5-diethyltoluenediamines (prepared according to Example 10)
M-DEA = 4,4'-Methylenebis(2,6-diethylaniline)
M-CDEA = 4,4'-Methylenebis(3-chloro-2,6-diethylaniline)
MOCA = 4,4'-Methylenebis(2-chloroaniline)
E-300 = 3,5-Bis(methylthio)toluenediamines (isomeric mixture of 2,4- and 2,6-diamine)
The new chain extenders and curing agents I for polyurethanes and epoxies show an
increase of the gel time as compared to DETDA. As these amines are liquid/semi
crystalline at room temperature, they can be processed at much lower temperatures as
compared to other aromatic amines (M-DEA, M-CDEA, MOCA).
If I is mixed with the diol Voranol ® EP 1900 (polyetherdiol based on polypropylene
glycol with an OH number of 26-29 and a Mw of 3800 g/mol from DOW) in the ratio
between 25% and 75% and reacted with the isocyanate Suprasec® 2008 (prepolymerized
diphenylmethane diisocyanate (MDI) with an isocyanate value of 10.2%, an
average functionality of 2.0 and a viscosity of 1800 mPa s at 25 °C, available from
Huntsman Polyurethanes), an increase of the gel time is detected compared to DETDA.
On the amine market, E-300, MOCA and M-CDEA are the amines with long gel times,
therefore these results were compared with those of the halogenated diethyltoluene
diamines of the present invention.
Example 13
Polyurethane gel time measurements
The halogenated diethyltoluenediamines according to the invention were used as
chain extenders and curing agents in polyurethane formulations. They were dissolved
and premixed in Voranol® EP-1900 at a temperature of 20 °C up to 50 °C, followed by
a quick mixing. The solution was then allowed to cool down to room temperature. Then
the isocyanate Suprasec® 2008 was added. The molar ratio of isocyanate groups to
the sum of amino and hydroxy groups was 95:100 in all tests. The gel time was
measured at 25 °C using a Gelnorm® gel timer (Gel Instrumente AG, Thalwil, Switzerland)
according to DIN 16945. For comparison purposes the gel times of similar
formulations with the known curing agents DETDA, E-300, M-CDEA and MOCA have
also been determined. The results are compiled in Table 1 below. (Tests Nos. C1-C13
are comparative tests.)
The results show a quite substantial increase of the gel time as compared to the nonhalogenated
DETDA. The range of obtainable gel times is significantly wider than with
M-CDEA, which provides the used with more flexibility in processing the polyurethane
formulations.
Table 1
* Too reactive, not possible to determine.
Example 14
Epoxy resin gel time measurements
The gel time in epoxies was measured as follows:
Bisphenol A diglycidyl ether (produced from bisphenol A and epichlorohydrin, commercially
available as Epikote™ 828 EL, Hexion Specialty Chemicals (Columbus OH,
USA) was mixed at 40 °C with the viscous halogenated diethyltoluenediamine of
formula I (DETDA-Br and DETDA-CI). The amounts of epoxy resin and curing agent
were chosen to obtain a molar ratio of epoxy groups to amino groups of 1: 1 . The
mixture was stirred to obtain a homogeneous viscous solution and then cooled to
25 °C. The gel times of the viscous preparations were determined using a Gelnorm®
gel timer (Gel Instrumente AG, Thalwil, Switzerland) according to DIN 16945 at
130 °C, 150 °C and 180 °C. For comparison purposes the tests were repeated with E-
300, M-CDEA, MOCA and DETDA (Test Nos. C14-C17). The results are compiled in
Table 2 below.
Table 2
Test. Amine Epikote™ Gel Time [min]
No. Type/Amount [g] 828 EL [g] @ 130 °C @ 150 °C @ 180 °C
7 DETDA-Br/6.43 18.6 179 89 32
8 DETDA-CI/5.32 18.6 156 78 28
C14 E-300/3.76 18.6 264 116 34
C15 M-CDEA/9.48 18.6 265 128 48
C16 MOCA/6.68 18.6 129 60 19
C17 DETDA/4.46 18.6 32 14 5

Claims
1. A halogenated diethyltoluenediamine of formula
wherein either R1 is an amino group and R2 is chlorine or bromine or R2 is an
amino group and R is chlorine or bromine,
or an isomeric mixture thereof.
2. The halogenated diethyltoluenediamine of claim 1, wherein either R is an amino
group and R2 is chlorine or R2 is an amino group and R is chlorine, or an iso¬
meric mixture thereof.
3. The halogenated diethyltoluenediamine of claim 1, wherein either R is an amino
group and R2 is bromine or R2 is an amino group and R is bromine, or an iso¬
meric mixture thereof.
4 . Use of a halogenated diethyltoluenediamine according to any of claims 1 to 3 as
a chain extender or curing agent in the production of polyurethanes.
5. Use of a halogenated diethyltoluenediamine according to any of claims 1 to 3 as
a hardener for epoxy resins.
6. A process for the preparation of the halogenated diethyltoluenediamine according
to claim 2, comprisin enediamine of formula
wherein either R1' is an amino group and R2' is hydrogen, or R2' is an amino group
and R ' is hydrogen,
or an isomeric mixture thereof,
with chlorine in sulfuric acid.
The process of claim 6 , wherein the sulfuric acid is present in an amount of 5 to
50 molar equivalents, based on the amount of diethyltoluenediamine (II).
The process of claim 6 or 7, wherein the chlorine is added in an amount of 2 to 10
molar equivalents, based on the amount of diethyltoluenediamine (II).
The process of any of claims 6 to 8, wherein the reaction temperature is between
15 °C and 80 °C.
0. A process for the preparation of the halogenated diethyltoluenediamine according
to claim 3, comprising the steps of
(i) reacting a diethyltoluenediamine of formula
wherein either R is an amino group and R2' is hydrogen, or R2' is an amino
group and R is hydrogen,
or an isomeric mixture thereof,
with an acetyl und of formula
wherein either R1" is an acetylamino group and R2" is hydrogen or R2" is an
acetylamino group and R1" is hydrogen,
or an isomeric mixture thereof,
brominating said diacetyl compound (III) with hydrobromic acid and hydro¬
gen peroxide to obtain a corresponding brominated diacetyl compound of
formula
wherein either R "' is an acetylamino group and R2"' is bromine or R2-' is an
acetylamino group and R "' is bromine,
or an isomeric mixture thereof, and
(iii) hydrolyzing said brominated diacetyl compound (IV) to obtain the corre¬
sponding brominated diethyltoluenediamine (I).
1 . The process of claim 10, wherein the acetylating agent in step (i) is acetyl
chloride in the presence of triethylamine.
12. The process of claim 10 or 11, wherein the bromination step (ii) is conducted at a
temperature of -10 to +20 °C.
13. The process of any of claims 10 to 12, wherein the hydrolysis step (iii) is con¬
ducted with hydrochloric acid in methanol.
14. A brominated diacet l compound of formula
wherein either R "' is an acetylamino group and R2"' is bromine or R2" is an acetylamino
group and R1'" is bromine,
or an isomeric mixture thereof.