Note: Descriptions are shown in the official language in which they were submitted.
~8~
The present invention is directed to a process for
the removal of nitrosamines from dinitroanilinesl by the use ~`
of hydrochloric acid or gaseous HCl.
The dinitroaniline class o~ compounds includes
numerous commercial herbicides. Recently a new analytical ;
device, known as a thermal energy analyzer (TEA), has been
developed (J. Chromatogr. 107 (1975), 351 and references
there cited; and "N-Nitroso Compounds in the Environment,
IARC Scientific Publication #9 (International Agency for ~-
Research on Cancer, Lyon, 1974), p. 40). The TEA analyzes
specifically for the nitroso (-NO) group, and is capable of
.. -, , .
detecting the nitroso yroup at concentrations as low as 0.02
ppm - much lower than prior analytical techniques. Analysis
of various dinitroanilines by the TEA reveals that some of
the dinitroanilines contain very small amounts of nitro-
samines. The presence of even a very small amount of
nitrosamine is viewed as undesirable, because certain of the
nitrosamines have been shown to be carcinogenic in animals.
The present invention provides a method for
removing nitrosamines from dinitroanilines.
The chemistry of aliphatic N~nitrosamines is
reviewed in Russian Chem. Rev. _0 (1) 34-50 (1971) (Eng.).
The reaction of nitrosamines with inorganic acids ~pa~e 41
et seq.) is covered. The reaction of hydrochloric acid and ~ ;
gaseous HCl with nitrosamines is discussed. ~ ,
Chem. Listy 51 937-945 (1957) reports on the
kinetics and mechanism of the conversion of nitrosamines to
the corresponding simple amines by strong mineral acids. ~
~' :
X-4775A -2- ~
~ ~ .
: ~ , - : .: . ': ,
~3lZS6
Lieb. Ann. 345 277-288 (1906) teaches the prep-
-
aration of di-n-propylamine by treatment of nitrosodi-
n-propylamine with gaseous HCl.
None of these references teaches the use of HCl
to remove nitrosamines from the particular dinitroanilines .
of the present invention. Moreover, it is unexpected that
this removal would be achieved so efficiently by the use
of HCl.
The amount of nitrosamines present in dinitro-
amines can be si~nificantly reduced with this invention.
This invention provides a process which comprises
(1) contacting a nitrosamine-containing
dinitroaniline selected from the group
consisting of ..
trifluralin,
~, isopropalin,
~3 benefin, .
~,~, . ...
~^~ . ethalfluralin,
butralin,
~'~1 , . ' .
~ 20 tendimethalin,
3 fluchloralin,
~)
profluralin,
dinitramine,
4-trifluoromethyl~2,6-dinitro-3-
chloro-N,N-diethylaniline,
4-methyl-2,6-dinitro-N,N-bis(2- `~ :~
chloroethyl)aniline,
oryzalin, and ~ ~ .
nitralin,
.
X-4775A -3-
~8~'~S6
,.t~
f` J (a) in liquid phase
~`. (b~ with a reagent selected from the
group consisting of 20-38% hydro- :~
chloric acid and gaseous HCl until
~' the concentration of the nitrosamine
; '. ~,.
has been reduced; and -~
(2) thereafter recovering the dinitroaniline.
The present invention is directed to a process
which comprises contacting a nitrosamine-containing dinitro- . :
10 aniline in liquid phase with a reagent selected from the ~ :
group consisting of hydrochloric acid and gaseous HCl, until
the concentration of the nitrosamine has been reduced; and
thereafter recovering the dinitroaniline. Dinitroanilines
with which the present invention can be practiced (and their ;
generic names where available) are ~ .
(1) 4-trifluoromethyl-2,6-dinitro-N,N-di-n- :
propylaniline (trifluralin); .
(2) 4-isopropyl-2,6-dinitro-N,N-di-n-propyl- .-
aniline (isopropalin)i
(3) 4-trifluoromethyl-2,6-dinitro-N-n-butyl-
N-ethylaniline (benefin); -~
(4) 4-trifluoromethyl-2,6-dinitro-N-ethyl- ~,
N-methallylaniline (ethalfluralin);
(5) 4-tert-butyl-2,6-dinitro-N-sec-butylaniline
(butralin);
(6) 3,4-dimethyl-2,6-dinitro-N-(l-ethylpropyl)-
aniline (tendimethalin); ~ :
(7) 4-trifluoromethyl-2,6-dinitro-N-propyl-
N-(2-chloroethyl)aniline (fluchloralin); .
(8) 4-trifluoromethyl-2,6-dinitro-N-propyl-
N~(cyclopropylmethyl)aniline (profluralin); ::
(9) 4-trifluoromethyl-2,6-dinitro-3-amino-
N,N-diethylaniline (dinitramine);
~ :
X-4775~ -4-
L, ~ . . . ~ ~ .. .. . .
~8~ 5~;
(10) 4-trifluoromethyl-2,6-dinitro-3-chloro-
N,N-diethylaniline (intermediate to ditramine);
(ll) 4-methyl-2,6-dinitro-N,N-bis(2-chloroethyl)-
aniline;
(12) 4-sulfamoyl-2,6-dinitro-N,N-di-n-propyl-
aniline (oryzalin); and
(13) 4-(methylsulfonyl)-2,6-dinitro-N,N-di-
n-propylaniline (nitralin).
Preferred dinitroanilines with which the present invention
is carried out are trifluralin, isopropalin, benefin, and
ethalfluralin.
Generally, the dinitroanilines are prepared by a
reaction route of which the following, for trifluralin, is
typical:
CF~ ~ ~ Cl H2SO~ 3 CF3 \ _~oCI 700 ~ CF3 ~ ~ON(n C3H7)2
It is believed that small amounts of nitrogen oxides re-
maining from the nitration step react with a portion of the
amine during the amination step, generating small amounts of
nitrosamine which may appear in the final dinitroaniline
product. Therefore, any nitrosamine contaminant is expected
to be the nitroso derivative of the alkylamine employed.
However, it is conjectured that exceedingly small amounts of
yet other nitrosamines may also be formed. The removal of
nitrosamines, regardless of identity, is decirable, and the ~;
present process meets that objective.
The mechanism by which the present process operates ~`
is not known with certainty, but it is believed that HCl ;~
denitrosates the nitrosamine to some other species, probably `~
the HCl salt of the corresponding amine. It is also believed
X-4775A -5
~IL08~25~i
. .
but not yet proven that NOCl may be yenerated as part of the
denitrosation. In any event, the net result is conversion
~ ~ .
of the undesirable nitrosamine to a water soluble substance
which can readily be removed ~rom the dinitroaniline.
The present process provides substantial reduction
in nitrosamine concentration, regardless o~ the initial
amount of nitrosamine. The process has been conducted with
dinitroanilines containing from as little as ~0 ppm
of nitrosamine to as much as several thousand ppm of - ~;~
nitrosamine, nitrosamine concentration is generally reduced
to about one-tenth of the initial amount, or less. In many
cases, the nitrosamine concentration is reduced to less than ;
about 1 ppm.
The present process is conducted in a liquid
phase. In the instance of many of the dinitroanilines, this
can be achieved by heating the nitrosamine-containing
dinitroaniline to its melting temperature or higher and
conducting the reaction neat. A liquid phase can also be `
achieved by dissolving the nitrosamine-containing dinitro-
aniline in a solvent. Suitable solvents include alcohols
such as ethanol: ketones such as acetone; and hydrocarbons,
both aliphatic and aromatic. Solvents comprising moieti.es
reactive with HCl should be avoided. For example, secondary
and tertiary alcohols should be avoided because of their
reactivity with HCl.
The reagent to be employed in the present process
is either hydrochloric acid or gaseous HCl. If hydrochloric
acid is used, it should contain at least 20% HCl (by weight).
Better results have been obtained with more concentrated
X-4775A -6-
., - . . . ,:
.
lZ~
hydrochloric acid, such as 33-38%. Gaseous HCl can also be
employed, and this is generally a preferred mode of carrying
out the present invention. In the instance of ethalfluralin,
gaseous HCl has an advantage over hydrochloric acid o~
avoiding addition across the methallyl double bond.
The amount of hydrochloric acid or gaseous HCl to
be employed is not critical, so long as the amount is
effective to reduce the initial amount of nitrosamine to a
lesser amount. With hydrochloric acid, 0.04 gram per 100
grams of dinitroaniline has been found satisfactory.
Similary, employing gaseous HCl, 250 ml. per 100 grams of
dinitroaniline has been found satisfactory. Larger amounts
(by 3X) have also worked satisfactorily but have provided no
advantage. In laboratory scale reactions with gaseous MC1,
addition rates of 5-90 ml./min./100 grams of dinitroaniline
have been satisfactorily employed. Rates of 8-12 ml./min/100
grams of dinitroaniline are preferred.
The reaction can be conducted at temperatures over
a wide range. In general, temperatures below 140QC. are
employed, and temperatures below 100C. are preferred
because of the greater risk of side reactions at higher
temperatures. When conducting the process in a solvent,
satisfactory temperatures vary widely with the identity of
the solvent, but generally range from room temperature to
100C. When conducting the process neat, the reaction is
conducted at temperatures above the melting temperature of
the particular dinitroaniline. Good results have been
achieved at temperatures of from 70 to 90C. when conducting
the process neat with trifluralin (m.p., 54-5C.), iso-
X-4775A -7-
, . - ~ -
~81~5~
propalin (m.p., 30C.), benefin (m.p., 65-6C.), and ethal-
fluralin (m.p., 57-9C.).
The reaction can be conducted at atmospheric
pressures or at elevated pressures. It has been found to be
advantageous to conduct the reaction with gaseous HC1 at
70-90C., and with 1 10 psig, and preferably 3-5 psig, of
HCl gas pressure.
The presence of water in the nitrosamine-con-
taining dinitroaniline has a deleterious efect on the
present process. This is especially true when employing
gaseous HCl in that more HCl is required for denitrosation.
Therefore, when employing gaseous HCl, it is preferred that
the nitrosamine-containing dinitroaniline be relatively dry,
such as less than 0.2 percent of water.
The rate at which the present process proceeds
will vary with the concentration of the nitrosamine, tem-
perature, the form of HCl reagent, the rate of its addition, -
and other factors. The progress of nitrosamine removal can
be monitored by gas chromatography or by TEA analysis.
Denitrosation is generally complete in less than an hour.
Time studies of the present process have shown an early drop
in levels of nitrosamine, followed in some instances by a
slight rise in levels of nitrosamine upon extended reaction
time. It is believed that extended exposure of (1) the
dinitroaniline and (2) the conjectured alkylamine denitrc-
sation product, to the reaction conditions may result in
further nitrosamine formation. Therefore, minimizing
reaction times is desirable.
. ~ .
X-4775A -8-
lO~ZS~
Workup of the reaction mixture is carried out by
conventional procedures. The workup desirably takes the
form of a water wash followed by a slightly basic wash to
assure removal of traces of HCl. Provision should also be
made, during the course of the present denitrosation process,
for the removal of by-product gases
The following examples illustrate the present
invention and will enable those skilled in the art to
practice the invention.
Unless otherwise noted, determination of nitro-
samine concentration in the following examples was done by a
gas chromatographic method sensitive down to about 0.5 ppm.
A `'non-detectable" reading (reported below as "N.D.") was
considered to represent less than about 0.5 ppm of nitro-
samine. A Hewlett-Packard Model 5711A gas chromatograph was
used but the method can be carried out with any gas chroma- :
tograph apparatus equipped with a flame ionization detector.
The column was ~ glass coil 4 ft. x 1/8 inch i.d., pac ~ d
with 3% Carbowax 20M on 100/120 mesh AW DMCS Chromoso G
operated at 100C. After the nitrosamine peaX eluted, the
column was heated to 230C. and held there for about 15
minutes. The helium flow rate was 60 ml./min. A standàrd
was employed of approximately the same concentration of the `
nitrosamine expected of the sample. Both staddard and
sample were prepared in méthylene chloride.
Those examples utilizing TEA analysis are so
indicated. Analyses by this method were carried out in
essentially the same procedures as described at J. C~romatogr.
109 (1975), 271. In the-context of the present invention,
X-4775A ~9-
.
z~
this method is considered to be sensitive to nitrosamineconcentrations as low as 0.05 ppm. Where TEA analysis of
the samples reported below showed no nitrosamine, it is
reported as "N.D."
In Example 2, a gas chromatography-mass spectrometry
method of analysis is reported. In this method, samples
were dissolved in benzene and purified by alumina column
chromatography using benzene as the eluting solvent. The
nitrosamine content of the sample was measured on an LKB-~000
gas chromatograph-mass spectrometer equipped with a 5%
Carbowax 20M column. The column temperature was adjusted to
130C. which resulted in a retention time of two minutes for
nitrosodi-n-propylamine. It was detected by adjusting the
magnet to the molecular ion (m/e = 130) and displaying the ~:
resulting ion current on a strip chart recorder.
EXAMPLE 1: NITROSAMINE REMOVAL FROM TRIFLURALIN, 20%
HYDROCHLORIC ACID, ETHANOL SOLVENT
Trifluralin (30 grams), containing 256 ppm. of
nitrosamine, was mixed with 20 ml. of 20~ hydrochloric acid
and 5 ml. of ethanol. The mixture was heated to 90C. and
maintained at that temperature, with stirring, for 3 hours.
The layers were separated and the organic layer washed with
10 percent sodium bicarbonate. The product was analyzed for
nitrosamine; none could be detected.
EXAMPLE 2: NITROSAMINE REMOVAL FROM TRIFLURALIN, HCL GAS,
BENZENE SOLVENT
Trifluralin (10 grams of a sample containing 480
ppm. of nitrosamine) was dissolved in 200 ml. of benzene and
the solution stirred and heated to reflux (80C.). HCl gas
X-4775A -10-
~ I
25~
was passed into the refluxing solution continuously over a
period of an hour. The reaction mixture was cooled slightly
and washed twice, each time with an equal volume of water.
The henzene layer was separated, dried over anhydrous
magnesium sulfate, and filtered, and the benzene was removed
on a rotary evaporator. The resulting trifluralin was
analyzed for nitrosamine content by a gas chromatography-
mass spectrometry method. Analysis showed <1 ppm of nitros-
amine.
EXAMPLE 3: NITROSAMINE REMOVAL FROM TRIFLURALIN, HCL GAS
Trifluralin (50 grams) was heated to 70C. HCl
gas was bubbled through at a rate of 8-12 ml./min. Samples
were taken at 0, 30, and 60 minutes. Each sample was washed
with 10 percent sodium carbonate solution, dried, and analyzed
for nitrosamine content. The results were as follows:
time when nitrosamine
sample taken concentration
0 32.6 ppm.
30 min. 2.9
60 min. N.D. ~;
EXAMPLE 4: NITROSAMINE REMOVAL FROM BENEFIN, 38% HYDRO-
CHLORIC ACID ;
Benefin (15 grams), containing 130 ppm. of nitros~
amine, was heated to 70C. Concentrated (38%) hydrochloric
acid (1.5 gram) was added and the reaction mixture was
stirred for 15 minutes. The organic layer was separated and
washed with a 10% sodium carbonate solution. The nitros-
amine content of the resulting product was 17 ppm.
X-4775A
56
EXAMPLE 5: NITROSAMINE REMOVAL FROM BENEFIN, HCL GAS
Benefin (25 grams), containing 130 ppm of nitros-
amine, was heated to 70C. HCl gas was bubbled through at a
rate of 8-12 ml./min. Samples were taken at 10, 20, 30
minutes. Each sample was washed with 10 percent sodium
carbonate solution and analyzed for nitrosamine content~
The result~ were as follows:
time when nitrosamine
sample takenconcentration
10 min. 65 ppm.
20 min. 38 "
30 min. 14 "
EXAMPLE 6: NITROSAMINE REMOVAL FROM ETHALFLURALIN, HCL
GAS
Ethalfuralin (100 grams) was heated to 70C. HCl
gas was bubbled through at a rate of 90 ml./min. Samples
were taken periodically. Each sample was washed with 2 ml.
of 10% sodium carbonate solution, dried, and analyzed for
nitrosamine content. The results were as follows:
time when nitrosamine
sample takenconcentration
0 10.2 ppm.
15 min. N.D.
30 min. N.D.
1 hour N.D.
EXAMPLE 7: NITROSAMINE REMOVAL FROM TRIFLURALIN, FASTER
RATE OF ADDITION OF HCL GAS ~ -
Trifluralin (50 grams) was washed with water for
30 minutes, and air-dried for 30 minutes. It was then
heated to 70~C. and HCl gas bubbled through at a rate of 35
ml./min. Samples were taken at 0, 15, 30, and 60 minutes.
Each sample was washed with 10~ sodium carbonate and analyzed
for nitrosamine content. The results were as follows:
X-4775A -12-
~)81'~56
time when nitrosamine
sample taken concentration
0 9.3 ppm.
15 min. <1
30 rnin. <1
1 hour <1
EXAMPLE 8: NITROSAMINE REMOVAL FROM TRIFLURALIN, HCl GAS,
EFFECT OF ADDED H2O
Trifluralin (100 grams) was heated to 70C. and
0.5 ml. of water was added. HCl gas was then bubbled in at
a rate of 8 ml./min. Samples were taken periodically; each
was washed with 10 percent sodium carbonate solution, dried,
and analyzed for nitrosamine content. The results were as
ollows:
time when nitrosamine ~
sample taken concentration ~ ;
0 27 ppm. ;"
10 min. 14 "
20 min 6.8 ppm
30 min. 3.2 " ;~
45 min. N.D.
EXAMPLE 9: NITROSAMINE REMOVAL FROM TRIFLURALIN, HCL GAS
OVER LONGER TIME
Trifluralin (100 grams) was heated to 70C. HCl
gas was bubbled through at a rate of 8-12 ml./min. Samples
were taken every 2 hours. Each sample was washed with 10%
sodium carbonate solution, dried and analyzed for nitros-
amine content. The results were as follows:
time when nitrosamine
sample taken concentration
48 ppm.
2 hours N.D.
4 hours N.D. ~
6 hours N.D. ?
8 hours 1.3 ppm.
X-4775A -13-
L2~;
EXAMPLE l0: NITROSAMI~E REMOVAL FROM ETHALFLURALIN, 38%
HYDROCHLORIC ACID
Ethalfluralin (85 grams), containing 9 ppm. of
nitrosamine by TEA analysis, was heated to 70C.; concen-
tra-ted hydrochloric acid (38%; 15 grams) added, and the -
reaction mixture stirred for 30 minutes. I'he layers were
separated and the organic layer was washed with 15 ml. of
water. The layers were again separated and the organic ~ `
layer washed with 15 ml. of 10% sodium carbonate solution
and then with 15 ml. of water. The organic layer was dried
at 120C. for 15 minutes. A sample was analyzed by TEA; no
nitrosamine was detected.
EXAMPLE ll: NITROSAMINE REMOVAL FROM TRIFLURALIN, HCL
GAS, FASTER RATE OF ADDITION :
Trifluralin (50 grams), containing 18 ppm. of ;
nitrosamine, was heated to 70C. HCl gas was bubbled in at a
rate of 90 ml./min. for 5 minutes. The trifluralin was then
washed with 5 ml. of 10% sodium carbonate and dried. A
sample analyzed for nitrosamine content showed none detectable.
EXAMPLE 12: NITROSAMINE REMOVAL FROM TRIFLURALIN, 38%
HYDROCHLORIC ACID OVER LONGER TIME
Trifluralin (60 grams) was heated to 70C. Con-
centrated hydrochloric acid (38%, 6 grams) was added and the
reaction mixture stirred. Samples were taken at intervals
and analyzed for nitrosamine content. The results were as
follows:
X-4775A -14-
~08~Z5G
time whennitrosamine
concentration
10 ppm
30 min.1.4 ppm.
1 hour 1.5
2 hours<1 "
3 1/2 hours 1.4 "
4 hours1.4 "
EXAMPLE 13: NITROSAMINE REMOVAL FROM TRIFLURALIN, HCL
GAS AT HIGHER TEMPERATURE
Trifluralin (100 grams) was dried for 30 minutes
at 120C. with air blowing over the surface. HCl gas was
10 then passed through at a rate of 12 ml./min. and a tem- -
perature of 85C. Samples, each 10 grams, were taken at 20,
40, 60, and g0 minutes. Each sample was washed with 5 ml.
of 5% sodium carbonate solution and dried on a rotary evap-
orator for 15 minutes at 90C. Results were as ~ollows: '~
t.ime when nitrosamine
sample taken concentration
011.1 ppm.
20 min.N.D.
40 min.N.D.
60 min.N.D.
90 min.N.D.
EXAMPLE 14: ~ITROSAMINE REMOVAL FROM ISOPROPALIN, HCL
GAS AND ELEVATED PRESSURE
To 1 liter of a xylene solution of isopropalin
(representing about 700 grams of isopropalin containing by ~;
TEA analysis 22 ppm. of nitrosamine) gaseous HCl was added
to a pressure of 5 psig and at a temperature of 70C.
Samples were periodically withdrawn; each was washed with
50% by volume of a 5% sodium carbonate solution, the layers ~ ~
' :
X-4775A - -15-
~08125G
separated, and the organic layer dried for 10 minutes at
60C. on a rotary evaporator. The results by TEA analyses
were as follows:
time when nitrosamine
sample taken concentration
-
o 22 ppm~
30 min. .22
60 min. .19 "
90 min. .4 "
120 min. .52 "
2 hours, 30 min. .40 " `
3 hours .28 "
3 hours, 30 min. .24 "
EXAMPLE 15: NITROSAMINE REMOVAL FROM ETHALFLURALIN, HCL
GAS
Ethalfluralin (100 grams)j containing 10.5 ppm. of
nitrosamine, was heated to 70C. and HCl gas was bubbled in
at a rate of 8 ml./min. Samples were removed periodically
and analyzed for nitrosamine content by the thermal energy
analyzer. Results were as follows:
time when nitrosamine
sample taken concentration
10 min. 10.9 ppm.
20 min. 6.6 "
30 min. N.D.
40 min. N.D.
EXAMPLE 16: NITROSAMINE REMOVAL FROM TRIFLURALIN, 38%
HYDROCHLORIC ACID RECYCLED
Trifluralin ~100 grams), containing 18 ppm. of
nitrosamine, was heated to 70C. and 20 yrams of 38% hydro-
chloric acid was added. The reaction mixture was stirred at
70C. for 30 minutes. The layers were then separated. The
organic layer was washed with 10 ml. of 10% sodium carbonate ;;
solution and analyzed for nitrosamine concentration. The
acid layer was saturated with HCl gas and used in another
X-4775A -16-
:-: . . . :
3L~8~;6
nitrosamine reaction with another 100 grams of trifluralin,
conducted under the same conditions as described above (the
first recycle). Two more recycles of the acid were made.
Results were as follows~
Nitrosamine
SampleConcentration
control (starting 18 ppm. ~
trifluralin) -
first acid treakment N.D.
first recycleN.D.
second recycleN.D.
third recycleN.D.
EXAMPLE 17: NITROSAMINE REMOVAL FROM TRIFLURALIN, HCL
GAS AND ELEVATED PRESSURE IN PILOT PLANT RUN
Trifluralin (210.0 kilograms) was melted overnight
(about 20 hours) at 70C. and charged into a 75 gallon
glass-lined still. The trifluralin was then heated to 90C.
and HCl gas passed in under pressure. The reaction conditions
were as follows:
HCl Nitrosamine
Time Temp._(C~ psig Sample # Concentration
0 90 0 #1 22 ppm
8 min. 91 2.5#2 3 " -
16 min. 90 2.5#3 N.D. ?
2022 min. 89 2.5#4 N.D.
39 min. 90 2.5#5 N.D.
65 min. 90 2.5#6 N.D.
71 min. 90 2.5#7 N.D.
Thereafter the reaction mixture was neutralized with sodium
carbonate and another sample taken; no nitrosamine could be
detected.
Total HCl used was 0.38 kilogram.
~ `
~' .
X-4775A -17-
11~18~'~5~
EXAMPL~ NITROSAMINE REMOVAL FROM TRIFLURALIN, HCL
GAS, ETHANOL SOLVENT
HCl gas was bubbled (12 ml./min.) into a mixture
of trifluralin (50 ml.) and ethanol (25 ml.) at 70C.
Samples were taken at 30 minutes and at 1 hour. Each sample
was worked up by stripping on a rotary evaporator for 15
minutes at 30C., and then washing with 5 ml. of 5 percent
sodium carbonate solution. The layers were separated and
the organic layer was stripped on a rotary evaporator for 15
minutes at 90C. Results were as follows:
time when nitrosamine
sample taken concentration
0 ~4 ppm.
30 min. 20 "
60 min. 14 "
EXAMPLE 19: NITROSAMINE REMOVAL FROM TRIFLURALIN, TWO
TREATMENTS WITH 38% HYDROCHLORIC ACID
Trifluralin (20 grams), containing 68 ppm. of
nitrosamine, and 5 ml. of 38~ hydrochloric acid were mixed
and held with stirring at 70C. for 20 minutes. The layers
were then separated, and to the organic layer, another 5 ml.
of 38% hydrochloric acid were added. The reaction mixture
was again maintained at 70C. for 20 minutes with stirring.
The layers were separated and the organic layer washed with
10 ml. of 10% sodium carbonate. The product was analyzed
for nitrosamine content. Nonè was detectable by gas chroma-
tography or TEA.
EXAMPLE 20: NITROSAMINE REMOVAL FROM DINITRAMI~E~ HCL ~AS ~
Dinitramine (10 grams of a sample containing ~; `
138 ppm of nitrosamine) was heated to about 110C. and HC1
X-4775A -18-
_.. _ . .
: . : ,, :
. . .
gas added at a rate of 35 ml~/min. for 45 minutes. After a
2 gram sample (labelled Sample l) was removed, the hot
remaining liquid was added slowly to 60 ml. of methylene
chloride. 15 ml. of lO percent sodium carbonate solution
was added. The organic phase was separated and solvent
removed from it on a rotary evaporator for 15 minutes at
45C., yielding 8 grams of yellow solid (labelled Sample 2).
Each sample was analyzed for nitrosamine content
by TEA. Results were as follows:
Nitrosamine
Sample Concentration
. . ~
l <0.2
2 <0.2
X-4775A -l9-
