Note: Descriptions are shown in the official language in which they were submitted.
Mo-2359
. LeA 21,086
PROCESS FOR ~E PREPARATIO~ OF
N-~IONO~UBSTITUTE~ O-ALKYLURE~HANES
BACKGROUND OF T~E INVE~ITION
The present invention relates to a process for the
preparation of ~ monosubstituted O-alkylurethanes in
which primary amines are reacted with N,N'-diarylureas
and high boiling monohydric alcohols. The arylamines
which split off during this reaction are removed by
distillation.
N-monosubstituted O-alkylure-thanes are valuable
intermedia~e products and end products which are becom-
ing commercially important as plant protective agents
and as starting materials in the preparation of iso-
cyanates.
N-monosubstituted O-alkylurethanes are conventional-
ly prepared by reacting the corresponding isocyanates
with alcohols or by reacting corresponding amines with
chloroformic acid esters. The isocyanates or chloro-
formic acid esters are made using phosgene which re-
quires considerable safety measures due ~o i~5 high
toxicity.
N-monosubstituted O-alkylurethanes may also be pre-
pared by reacting appropriate nitrogen compounds with
carbon monoxide in the presence of alcohols. Processes
for the preparation of urethanes from nitro compounds
by a reaction with carbon monoxide and alcohols have
been described in German Offenlegungsschriften
2,603~574 and 29614,101. One disadvantage of this meth-
od is that carbon monoxide, which is toxic and combust-
~0 ible, must be used under pressure so tha~ elaboratesafety measures are necessary. In addition, such
carbonylation reactions require the use of special
catalyst systems, which entail considerable costs.
Mo-2359 U~
US Patent 2,806,051 discloses a process Eor the
preparation of N-monosubstituted O-alkylurethanes in
which primary amines are reacted with urea and
alcohols, and the ammonia formed is removed from the
reaction mixture. Although the use of urea as startinV
material is theore~ically advantageous, it has been
~ound to be disadvantageous in practice, tparticularly
when weakly basic amines or polyfunctional amines are
used) because the reaction is accompanied by formation
of N-unsubstituted carbamic acid esters as well as cya-
nuric acid, polyureids and other irreversible decom-
position products of urea as by-products. ~hen N,N'-di-
substituted ureas are formed as by-products, they
separate as difficultly soluble oligoureas or polyureas
if polyfunctional amines are used and may interfere
with the production process. The resulting product
mixtures may require elaborate and expensive processes
for working up, particularly if the reactions have not
been complete and the mixtures still contain residual
amines. The desired urethane may be obtained in only
moderate yields. The difficulties outlined above are
particularly pronounced when weakly basic amines or
poly~unctional amines are used. These disadvantages
are not overcome by the processes described in German
Offenlegungsschriften 2,917,493 and 2,917,569, in which
di- and/or polyamines are reacted with urea and
alcohols.
Similar disadvantages occur in the preparation of
N-monosubstituted O-alkylurethanes by the reaction of
primary amines ~ith N-unsubstituted carbamic acid
esters and optionally urea and optionally alcohols, in
which the ammonia formed is removed from the reaction
~o=2359
4S7
mixture. This method of preparation has been
described, for example, in German Offenlegungsschriften
2,917,490 and 2,917,568 and in European Patent Specifi-
cations 0,018,581 and 0,018,583~ These processes ~ive
rise to the same irreversible by-products obtained when
urea is used as the starting material. Furthermore,
N-unsubstituted carbamic acid esters react much more
slowly than urea so that the reaction is incomplete,
particularly when weakly basic amines or polyfunctional
amines are used.
SUMM_ARY OF ~IE INVENTION
It is an object of the present invention to provide
a process for the preparation of N-monosubstitu~ed O-al-
kylurethanes.
It is also an object of the present invention to
pro~ide a process for the preparation of N-mono-
substituted O-alkylurethanes in high yield without
f~rmation of significant quantities of by-products.
It is another object of the present invention to
provide a process for the preparation of M-mono-
substituted O-alkylurethanes which is more economical
and requires less elaborate safety ~easures than prior
axt processes.
These and other oojects which will become apparent
to those skilled in the art are accomplished by re-
25 acting a primary amine corresponding to a specifiedformula with a urea of a specified formula and a
primary or secondary alcohol at a temperature of from
150 to 300C. The amine which forms durlng the re-
ac~ion is re~o~ed ~rom the reaction mixture by distil-
30 lation on a continuous basis. The reactant alcohol hasa boiling point which is at least 5C higher at atmosph-
Mo-2359
~L~82~
eric pressure than the aromatic amine from ~hich the
urea is directed.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a process for the
preparation of N-monosubstituted O-alkylurethanes corre-
sponding to the general formula
Rl (NH CO-OR ) n
in which
Rl represents an aliphatic hydrocarbon group
having a total of 4 to 18 carbon atoms, option-
ally containing inert substituents; a cycloali-
phatic hydrocarbon group having a total of 6
to 28 carbon atoms, optionally containing
inert substituents and/or oxygen, sulfur or
alkylene groups as bridge members; an aromatic
hydrocarbon group having a total of 6 to 28
carbon atoms~ optionally containing inert sub-
s~ituents and/or oxygen, sulfur or alkylene
groups as bridge members; or an araliphatic
hydrocarbon group having a total of 7 to 28
carbon atoms, optionally containing inert sub-
stituents;
R denotes an aliphatic hydrocarbon group having
a total of 6 to 18 carbon atoms, optionally
containing inert substituents and/or ether
groups; a cyc.loaliphatic hydrocarbon group
having a total of 6 to 15 carbon atoms, option-
ally containing inert substituents; or an aral-
iphatic hydrocarbon group having a total of 7
to 18 carbon atoms, optionally containing
inert substituents; and
n denotes an integer greater`than or e~ual to 1.
Mo 2359
~%~
These urethanes are made by reacting a primary amine
with an N,N'-diarylurea and a primary or secondary
alcohol at a temperature o~ from 150 to 300C and con-
comitantly removing by distillatlon the aromatic mono-
amine R3NH2 which forms. The R3NH? may be re-
moved in admixture with the alcohol R -OH.
Primary amines which may be used in the practice of
the present invention correspond to the general formula
Rl(NH2)n
10 in which Rl and n are as defined above.
Ureas which may be used in the present invention
correspond to the general formula
R3-NH-CO-N~I-R
in which
15 R3 represen~s an aromatic hydrocarbon group
havin~ a total of 6 to 14 carbon atoms, option-
ally containing inert substituents, which
'nydrocarbon group is derived from a primary
aromatic monoamine (optionally containing
inert substituents) having a boiling point at
atmospheric pressure at least 1~C below ~he
boiling point of the amine Rl (NH2)n.
Primary or secondary alcohols which may be used in
the present invention correspond to the general formula
R2-OH
in which R is as defined above. The reactant
alcohol must have a boiling point at atmospheric
pressure which is at least 5C higher than the amine
R -N~12.
The primary amines of the above-mentioned general
formula used as starting materials are preferably those
in which
Mo-2359
~8~
-- 6--
Rl represents a saturated, unsubstituted, ali-
phatic hydrocarbon group having 4 to 18 carbon
atoms; a saturated cycloaliphatic hydrocarbon
group having a total of 6 to 25 carbon a~oms,
optionally alkyl substituted and/or carrying
methylene bridges, or an aromatic hydrocarbon
group having a ~otal of 6 to 25 carbon atoms
which is optionally alkyl-substituted and/or
halogen substituted and/or carries methylen~
bridges, and
lQ n represents 1, 2 or 3, most preferably 1 or 2.
Mixtures of primary amines corresponding to the
above-given formula may also be used. These monoamines
must have a boiling point at atmospheric pressure which
is at least 10C higher, preferably at least 25C
higher than the boiling point of the monoamine from
which the reactant disubstituted urea is derived.
Therefore, when the monoamines corresponding to the
above-mentioned general formula are alipha~ic or cyclo-
aliphatic monoamines without substituents, Rl must
have at least 9 carbon atoms. If aromatic monoamines
are used, they must be di~ferent from the monoamine
from which the reactant urea is derived and must
satisfy the difference in boiling points requirement
described above.
Examples o suitable primary amines are: decyl-
amine, iso-dodecylamine, n-stearylamine,
2~(2-butoxy-ethoxy)-ethylamine,
l-butyl-4-methoxy-butylamine , 3-butyl-
cyclohexylamine,4-cyc~ohexyl-cyclohexylamine, 4-chloro-
aniline3 3,4-dichloroaniline, 3-toluidine, 3-chloro-4-
methyl-aniline, 3,5-dimethyl aniline, 4-cyclohexyl-anil-
Mo-2359
~2~
ine, 4-benzyl-aniline, 3-anisidine, 3-amino-benzoic
acid nitrile, l-naphthylamine, 2-naphthylamine,
2-phenyl-ethylamine, tetramethylenediamine,
hexamethylenediamine,
2 7 2,4-trimethylhexamethylenediamine, isophoronediamine,
1,4-diamino-cyclohexane, 4,4'-diamino-dicyclo-
hexylmethane, 2,4-diamino-1-methyl-cyclohexane, 2,6-di-
amino-l-methyl-cyclohexane; 4-aminocyclohexyl-4'-amino-
phenyl-methane, 6-(2-aminophenyl-mercap~o)-hexylamine,
1,3-diaminobenzene, 2-chloro-1,4-dia~inobenzene, 2,4-di-
aminotoluene, 2,6-diaminotoluene, 2,4-diamino-3,5-di-
ethyltoluene, 1,5-diaminonaphthalene, 2,7-diamino-
naphthalene, 2,2'-diamino-diphenylmethane, 2~4'-diamino-
diphenylmethane, 4,4'-diamino-diphenylmethane, 3,3'-di-
chloro-4,4'-diamino-diphenylmethane 9 2,2-bis-(4' amino-
phenyl)-propane, l,l-bis-(4'-aminophenyl)-cyclohexane,
4,4',4"-tria~ino-triphenylmethane,
4,4'-diamino-diphenylether, 1,3-~ylylenediamine,
1,4-xylylenediamine, 3,4'-diamino-4-methyl-dlphenyl-
20 methane, and 4,4'-diamino-diphenyl sulphide.
The diamino-diphenylmethane isomers listed above
may also be used as mixtures wi-th higher nuclear homo-
logs, i.e. for example in the form of aniline-formal-
dehyde condensates known as "polyamine mixtures of the
25 diphenylmethane series"which are obtained in the
presence of acid catalysts.
Examples o~ reactant diarylureas which may be used
in the present invention are: N,N'-diphenylurea,
N,N'-di-(2-tolyl)-urea, N,N'-di-(3~tolyl)-urea, N,N'-di-
(4-tolyl)-urea, N,N'-di-(3-e-thylphenyl)-urea, N,N'-di-
(4 ethylphenyl)-urea, N,N'-di-(3-methoxyphenyl)-urea,
and N,N'-di-(4-methoxyphenyl)-urea. The preferred N,N'-
Mo-2359
-- 8--
diphenylurea for the process of the present invention
is NrN~-diphenylurea.
The reactant alcohols which may be used in the
process of the present invention are primary or
secondary, preferably primary D~onohydric alcohols which
have a boiling point at atmospheric pressure that is at
least 5C, preferably at least 20~C higher than the
boiling point of the amine R3-~2 rom which the
diarylurea R3-NH-Co-NH-R3 is derived. The alcohols
in which R represents a saturated primary aliphatic
hydrocarbon group having 6 to 18 carbon atoms ? option-
ally contain ether bridges.
Examples o~ suitable alcohols are: straight chained
or branched octanol, nonanol, decanol, undecanol, dodec-
anol, tetradeeanol, hexadecanol or octadecanol; 2-(2-
ethoxy-ethoxy)-ethanol; 2-~2-butoxy-ethoxy)-ethanol;
2-phenylethanol; 2-phenoxyethanol; 2-(2-phenoxy-ethoxy)-
ethanol; cyclooctanol, benzyl alcohol; 2,4,5~trimethyl-
cyclohexanol; 1,2,3,4-tetrahydro- naphthol-(2); and
20 perhydronaphthol-(2). Mixtures of alcohols R2-OH
may, oE course, also be used.
The diarylureas R3-NH-Co-NH-R3 used in the
process of the present invention may be prepared by
methods known in the art, for example by the reaction
25 of aromatic amines with carbon dioxide as described in
British Patent 622,955. A simple method of preparing
diarylureas in high yields, consists of reacting the
corresponding arylamines R -NH2 with urea and re-
moving the ammonia formed (see also Liebigs Ann. Chem.
30 131, 251 (1864). The diarylurea~ used in the process
of the present invention may, however, be prepared by
any method.
Mo-2359
The diarylureas R3-NH-Co-NH-R3 used in the
process of the present invention need not be hi~hly
pure. In particular, admixtures of the corresponding
arylamine R3-NH2 in the diarylurea do not inter~ere
s wit'n the reaction o~ the present invention because the
arylamine R3-NH2 is liberated in the reaction and
removed from the reaction mixture by distillation any-
way.
In one embodiment o:E the present invention, crude
diarylureas R3-NH-Co-NH-R3 obtained by reacting
urea with arylamine R -NH2 in a molar ratio o~ from
1:1.8 to 1:10 ~preferably 1:2 to 1:4) at a temperature
from 130C to 250C (pre~erably from 150C to 210C)
with liberation and removal of ammonia is used as a
reactant. Excess arylamine R3-NH2 present in the
crude diarylureas may be partially or completely
removed (for e~ample by distillation) before the
diarylureas are used in the process of the present
invention. Alternatively, the crude diarylureas may be
used in the present invention without any further
treatment.
In the process of the present invention, the re-
actants are used in proportions such that the overall
molar ratio of amino groups of the amine
25 R (NH2)n to diarylurea R3-NH~Co-NH-R3 is in
the range o~ l:l to 1:5, preferably 1:1 to 1:1.5, most
preferably 1:1 to 1:1.05. The overall molar ratio of
amino groups of the amine Rl (NH2)n to the
alcohol R -0~1 should be in the rang~ of 1:1 to 1:20,
30 pre~erably 1:1.5 to 1:1Ø
The reaction of the present inven~ion is carried
out at a temperature of from 150C to 300C, preferably
1&0 to 250C.
Mo-2359
~2~
- 10-
The pressure used in the process of the present
invention should be adjusted so that the arylamine
R3-NH2 ~ormed in the reaction and/or already
present in the reaction mixture boils (optionally in
admlxture with the alcohol R -OH) and can be removed
by distillation. The pressure is generally from 0.001
to 1.5 bar, preferably from 0.01 to 1.1 bar.
The reaction of the present invention is generally
completed after a reaction time of 1 to 20 hours, pre-
ferably 2 to 10 hours, most preferably 3 to 6 hours.The reaction may be accelerated by the addition of a
catalyst to the reaction mixture. Suitable catalysts
include Lewis acids such as BF3, BC13,
B(OC2H5~3~ B(OC4Hg)3, AlC13, AlBr3,
SnC14, dibutyl tin oxide, SbC15, TiC14, TiBr4
FeC13, cobalt octoate, ZnC12, zinc octoate, CuCl,
and/or salts and comple~ compounds of transition metals
other than those belonging to the group of Lewis acids,
such as iron carbonyls, acetylacetonates of iron3
20 nickel, cobalt, zinc, manganese, molybdenum, ~itanium,
thorium, vanadium or zirconium, and bls-(dibenzoyl-
methane)-copper. Mixtures of such compounds may, of
course, also be used as the catalyst.
Particularly suitable catalysts-are zinc chloride,
25 zinc acetate, zinc octoate, zinc oxide, tin dichloride,
tin tetrachloride, dibutyl tin oxide 9 dibutyl tin di-
e~hylate, dimethyl tin dichloride, dibutyl tin di-
laurate, cobalt trichloride, cobalt triacetate, copper
chloride and copper acetate.
The catalyst, if used at all, is generally added to
the reaction mixture in a quantity of 0.001 to 5 wt. %,
preferably 0.01 to 2 wt. % (based on the total weight
Mo 2359
of the starting materials). One would, of course, aim
to keep tlle concentration of catalyst as low as
possible. The optimum catalyst concentra~ion depends
on the nature of the starting materials and the
activity of the particul2r catalyst, and may be
determined by a simple preliminary test.
In the process of the present in~ention, the
reaction may be carried out by mixing the amine
Rl(NH2)n, diarylurea R3~NH-Co-NH-R3 and
alcohol R2-OH and heating -the mixture in a
distillation apparatus at the required pressure. The
arylamine R3-NH2 formed in the course of the
reaction or possibly already present in the reaction
mixture is removed by distillation.
~hen carrying out the reaction of the present inven-
tion, it may be advantageous to first heat the diar~l-
urea R3-NH-Co-NH R3 and the alcohol R2 OH to the
required temperature at the necessary pressure in a
distillation apparatus in the absence of the amine
20 Rl (NH2)n or with only a proportion of the amine
R (~H2)n and then add the amine R 'NH2)n or
the remainder of ~he amine R (NH2)n into the
reaction mixture (op~ionally together wi~h the alcohol
R -0~) at a suitable rate. This method makes it
25 possible to avoid the presence of undeslrably high con-
centrations of the amine Rl(NH2~n in the reaction
mixture. This may be par~icularly important when using
polyfunctional amines Rl(NH2)n which form in-
soluble or difficultly soluble polyureas in the re-
30 action mixture.
Removal of the arylamine R3-~2 from the re-
action mixture by distillation as it is formed shifts
Mo-2359
the reaction equilibrium in the direction of the de-
sired end product, thereby ensu-ring quantitative conver-
sion of the amine Rl(N~2)n. Removal of the aryl-
amine R3-NH2 from the reaction ~mixture may be
carried out by any known distillation method. One such
method is a stripping distillation in which a condenser
is attached to the reac~ion vessel. It is generally
advisable, however, to fractionate the vapors escaping
from the reaction vessel by using a frac-tionating
column or a separating column. Fractionation techni-
ques make it possible to prevent removal of portions of
the amine Rl(~H2)n or of undesirable large quanti~
ties of alcohol R -OH from the reaction mixture
along with the arylamine R3-NH2.
It is not essential to the process of the present
invention that the arylamine R3-NH2 distilled from
the reaction mixture be free from alcohol R -OH. It
may even be an advantage, particularly towards the end
of the reaction to remove portions of alcohol R2-OH
from the reaction mixture together with the arylamine
R3-NH2 provided that sufficient quantities of
alcohol R2-o~ are le~t be'nind for the reaction.
The process of the present invention may be carried
out continuously or batchwise. For a continuous pro-
cess, it is advantageous to provide a series of re-
action vessels arranged in a cascade. It may then be
advantageous to use di~ferent reaction temperatures,
reaction prassures and/or average dwell times in the
various reaction vessels. Fractionation of the vapors
containing the arylamine ~3-~H2 released from the
reaction vessels may be carried out separately in each
reaction vessel (or example by attaching fractionating
Mo-2359
columns ~o the various vessels) or after mixing the
vapors from the various columns.
Any known apparatus may be used to carry out the
process of the present invention continuously.
~hen the reaction has been completed, any excess
alcohol R2-OH left in the reaction mixture may be
separa~ed ~rom the end product ~y distillation, prefer-
ably at reduced pressure.
The products obtained in the process of the present
invention are N-monosubstituted O-alkylurethanes corres-
ponding to the formula
Rl(NH-CO-OR )n
in which R , R and n are as defined above. The
process of the present invention proceeds according to
the ~ollowing equation:
Rl(NX2)n + n R3-NH-Co-NH R3 + n R2-OH
~ R (NH-CO-OR )n + 2n R -NH2
It was completely unexpected that the ormation of
substituted ureas derived from the amine Rl(NH2)n
is virtually eliminated in the process of the present
invention. The absence of polyurea formation when poly-
functional amines are used is particularly surprising.
Since the reaction is carried out at temperatures at
which O alkyl-urethanes normally decompose into iso-
cyanates and alcohols, one would have expected the for-
mation of isocyanates corresponding to the formula
Rl(NH~CO-OR2)n m(NCO)m 1 2
in the reaction mixture (~ith R , R and n being as
de~ined above) with n - m denoting a positive integer.
One would have expected these isocyanates to combine
with the amine component Rl (NH2)n to form un-
wanted ureas, however, this side reac~ion does not
occur to any significant extent.
Mo-2359
:'
- 14-
The products obtained by the process of the present
invention are carbamic acid esters based on relatively
high boiling alcohols If however, it is desired to
obtain carbamic acid esters based on lower boiling
alcohols ~as may be the case when preparing isocyanates
by thermal splitting of O-alkylurethanes), the products
of the process may be transurethanized to the desired
products by an exchange reaction with the corresponding
lower boiling alcohol. This method has been descxibed,
for example, in &erman O-ffenlegungsschrirt 29 43 549.
Having thus described our invention, the following
Examples are given by way o illustration. The per
centages given in these E~amples are percents by
weight, unless otherwise indicated.
EXAMPLES
15 Example 1
236 g of n-decylamine, 320 g of N,N'-diphenylurea
and 900 g of 2-phenyl-ethanol were introduced into a 2
liter round bottomed flask with a packed column at-
tached. The mixture was heated to 210C with vigorous
20 stirring. Stirring was continued at 210C at atmo-
spheric pressure for 4 hours, during which time aniline
was distilled over -the column. The reaction tempe-
rature was then raised to 230C and phenyl ethanol was
distilled off for 15 minutes. The crude mixture was
25 then Ereed from mos-t of the phenyl ethanol excess
present by ~he vacuum distillation (ini-tially at 20
mbar, finally a 1 mbar). The 472 g of crude product
left behind was analyzed by liquid chromatography
~HPLC). 96.l wt. % of the crude product consisted of
30 N-decyl-0-(2--phenyl-ethyl)-urethane. ~Yield: 99~ of the
theoretical yield) A to~al of 279 g of aniline was
detected in the distillate.
Mo-2359
,4~
Example 2
420 g of aniline and 92 g of urea were introduced
into a 2 liter round bottomed flask wit'n reflux con-
denser attached. The mixture was heat~d to 190C with-
in 30 minutes with stirring. Am~onia gas was released,removed by way of the reflux condenser and absorbed in
water in a scrubber. After an additional 1.5 hours,
during which the reaction temperature was raised to
200C, liberation of ammonia was completed. The appa-
10 ratus was briefly flushed with nitrogen to remove resi-
dues of ammonia gas. The reflux condenser was then
replaced by a distillation bridge. A solution of 404 g
of n-stearylamine in ~00 g of n-dodecanol heated to a
temperature of 190C was then introduced into the re-
15 action mixture with vigorous stirring. The mixture washeated to 230C and stirred for 5 hours a-t this temper-
ature and at atmospheric pressure, during which ~ime a
mixture of 417 g of aniline and 77 g of dodecanol dis-
tilled over. Most of the excess dodecyl alcohol was
20 then distilled of under vacuum and 774 g o crude
product remained behind. 5~18 g of the crude product
were separated by column chromatography against silica
gel. 4.73 g of N-octadecyl-O-dodecyl-urethane were
isolated. This corresponds to a yield of 98% of the
theoretical yield.
Exam~le 3
163 g of 2-12-(2 methoxy-ethoxy)-ethoxy~
-ethylamine, 213 g of ~,N'-diphenylurea and 700 g of
2 phenoxy-ethanol were introduced into a 2 liter round
bottomed flask with a packed column a~tached. The
mixture was h~ated to 220C at atmospheric pressure
with vigorous stirring. Aniline was liberated and
Mo-2359
- 16-
distilled over the column. The reaction temperature
was raised to 233C in the course of 4 hours, during
which aniline continued to be released and distilled
off. The major part of the excess alcohol was then
removed from the reac~ion mixture by vacuum
distillation (first at 20 mbar, then at 1 mbar) and 333
g of liquid crude product were left behind. According
to liquid chromatographic analysis (HPLC), the crude
product contained 96.6 wt % of N-2-
~2-(2-methoxy-ethoxy)-ethoxy~-ethyl-O-(2 phenoxy
-ethyl)-urethane (yield: 98% of theoretical yield). A
total of 186 g of aniline was detected in the
distlllate.
Exam~le 4
320 g of aniline and 73 g of urea were introduced
into a 2 liter round bottomed flask with a packed
column attached. The mixture was heated to 190C for
30 minutes with stirring. During this time, ammonia
gas was released, conducted away through the column and
absorbed in water. After an additional 1.5 hours,
during which the reaction temperature was raised ~o
200C, the release of ammonia was completed. The appa-
ratus was briefly -flushed with nitrogen, A solution of
170 g of 3-chloro-4-methyl-aniline in 900 g of
n-decanol heated to 190C was added to the reaction
mixture with stirring. The mixture was then stirred
for 5 hours at 225C and atmospheric pressure and
aniline was concomitantly distilled over the column.
The pressure was then 510wly reduced to 500 mbar until
pure decyl alcohol distilled over. Most of the decanol
excess was then distilled from the reactlon mixture,
first at 20 mbar, then at 1 mbar, and 370 g of crude
Mo-2359
- 17-
product remained behind. According to liquid chroma-
tographic analysis (HPLC), the crude pro~uct contained
95.7 wt. % of N-(3-chloro-4-methyl-phenyl~-
0-decyl-urethane (yield: 98% of t'neoretical yield). A
total of 318 g of aniline was detected in the
distillate.
Exam~le 5
A mixture of 195 g of 3,4-dichloroaniline, 257 g of
N,N'-diphenylurea and 1000 g of 2-phenoxy-ethanol was
lO heated to 230C with vigorous stirring in a 2 liter
round bottomed flask with a packed column a~tached.
Aniline was distilled of over a period of 6 hours at
230C and atmospheric pressure. The pressure was then
lowered to 500 mbar and distillation was continued
15 until pure phenoxy-ethanol distilled over. Most of the
phenoxy-ethanol excess was then separated by vacuum
distillation. 407 g of crude product remained behind.
According to liquid chromatographic analysis (HPLC),
this crude product contained 93.8 wt. % of
20 N-(3~4-dichlorophenyl)-o-(2-phenoxy-ethyl)-urethane
(yield: 97% of theoretical yield~. The crude product
was recrystallized from ligroin and yielded colorless
crystals melting at 79 to 81C. A total of 222 g of
aniline was detected in the distillate.
25 Example 6
470 g of aniline and 122 g of urea were heated to
190C with vigorous s~irring within 30 minutes in a 2
liter round bottomed flask equipped with a packed
column and a dropping funnel adapted to be heated.
30 Ammonia gas was released, escaped through the column
and was absorbed in water. Liberation of ammonia was
completed after an additional 1.5 hnours during which
- ~o-2359
.
. .
4~i~
the temperature was raised to 204C. The apparatus was
briefly flushed wlth nitrogen. 800 g of decanol at
200C and 1 g of dibutyl tin oxide were then added to
the reaction mixture and the mlxture was heated to
220C. A solution of 116 g of hexamethylene diamine in
400 g of n-decanol at 50C was introduced dropwise
within 4 hours with stirring at: atmospheric pressure
into the mixture which mixture was at a temperature of
220C. At the same time, aniline was distilled off
over the colu~l. After addition of the solution of
hexamethylene diamine had been comple~ed, the reaction
mixture was stirred for an addtional hour at 220C and
atmospheric pressure while aniline distilled over. The
pressure was then lowered to 500 mbar until pure
decanol distilled over. Lastly, most of th~ decanol
excess was separated by vacuum distillatlon and 502 g
of crude product remained behind. 4.93 g of the crude
product were separated by column chromatography against
silica gel. 4.69 g of hexamethylene-bis-caxbamic
acid-bis- decyl ester were obtained in the form of
crystals with a melting point of 113C (yield: 99% of
theoretical yield). A total of 467 g of aniline was
detected in the distillate.
Example 7
A mix~ure of 427 g of N,N'-diphenylurea9 1000 g of
2-phenoxy-ethanol and 1.5 g of dibutyl tin oxide was
heated to 215C with s~lrring in a 2 liter round bot-
tomed flask equipped with dropping funnel and a packed
column. After the pressure had been adjusted to 600
mbar, a solution of 116 g of hexamethylenediamine in
400 g of 2-phenoxy-ethanol was introduced dropwise in
the course of 4 hours into the homogeneous liquid re-
Mo-2359
_ 19-
action mixture which was at a temperature of 215C
while aniline was distilled over the column. After
addition of the solution of hexamethylenedîamine had
been completed, aniline continued to be distilled off
for an additional hour at 215C and 600 l~bar. The
pressure was then slowly reduced until pure phenoxy
ethanol distilled over. Lastly, most of the phenoxy
ethanol excess was removed by vacuum distillation and
465 g of crude product remained behind According to
liquid chromatograp'nic analysis (HPLC), 93.6 wt. % of
the crude product consisted of hexamethylene-bis-
carbamic acid-bis-(2-phenoxy-ethyl)-ester (yield: 98%
of theoxetical yield). Recrystalliza-tion of the crude
product from 1,2-dichloroethane yielded colorless
crystals with a melting point of 152C. A total of 370
g of aniline was detected in the dis~illate.
A mixture of 426 g of N,N'-diphenylurea and 1000 g
of 2-phenoxy-ethanol was heated to 230C with vigorous
stirring in a 2 liter round bottomed flask equipped
with dropping funnel and a packed column. A solution
of 210 g OL trans, trans-4,4'-diamino-dicyclo-
hexylmethane in 400 g of 2-phenoxy ethanol was intro-
duced dropwise in the course of 4 hours at atmospheric
pressure into the mixture which was at a temperature of
230C, and aniline was at the sa~e time distilled over
the column. After all the solution of dicyclohexyl-
methane had been added, stirring of the mixture was
continued -Eor an additional 1.5 hours at 230C while
~ aniline disti~led over. The pressure was then reduced
until pure phenoxy-ethanol distilled over. Lastly,
mos~ of the phenoxy-ethanol excess was removed from the
Mo-2359
67
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reaction mix~ure by vacuum distillation and 566 g of
cr-ude product remained behind. According to liquid
chromatographic analysis (HPLC), the crude product
contained 94.2 wt. % of dicyclohexylmethane-
4,4'-bis-carbamic acid-bis-(2-phenoxy-ethyl)-ester
(yield: 99% of theoretical yield). A total of 373 g of
aniline was detected in the distillate.
Example 9
A mixture of 426 g of N,N'-diphenylurea, 122 g of
2,4-diaminotoluene, 1300 g of 2-phenoxy-ethanol and 2 g
of dibutyl tin dilaurate was heated to 230C with vig-
orous stirring in a 2 liter round bottomed flask with a
packed column attached. The reaction mixture was stir-
red at 230C and atmospheric pressure for 6 hours while
aniline was distilled over the column. The pressure
was then lowered over 30 minutes until pure phenoxy
ethanol distilled over. Most of the phenoxy ethanol
excess was finally removed from the reaction mixture by
vacuum distillation. 455 g OL crude product remained
behind. According to liquid chromatographic analysis
(HPLC), the crude product contained 94.7 wt. % of
toluene-2,4-bis-carbamic acid-bis (2-phenoxy-ethyl)-
ester (yield: 96% of theoretical yield).
Recrystallization of the crude product from ethanol
yielded almost colorless crys~als with a mel~ing point
of 137C. A total of 364 g o aniline was detected in
tne distillate.
Example 10
A mixture of 430 g of 3-toluidine and 97 g of urea
was heated to 210C for 30 minutes with vigorous stir-
ring in a 2 liter round bottomed flask with dropping
funnel and a packed column. Ammonia gas was released,
Mo-2359
8 ~
- 21-
conducted away through the column and absorbed in
water. After the reaction had been continued for an
additional 1.5 hours at 210C, the liberation of
ammonia was completed. The apparatus was briefly
flushed with nitrogen. 1000 g of n-dodecanol heated to
~00C and 2 g of dimethyl tin dichloride were then
added to the reaction mixture and heated to 230C.
After the pressure had been adjusted to 500 mbar, a
solution of 98 g of 2,4-diaminotoluene in 350 g of do-
decanol was introduced dropwise in the course o~ 4hours into the reaction mixture which was at a temper-
ature o 230C, and 3 toluidine was distilled over the
column at the same time. ~hen all the solution of
2,4-diaminotoluene had been added, the mixture contin-
ued to be heated to 230C for an additional 2 hours at500 mbar while toluidine continued to distill over.
The pressure was then slowly lowered until pure do-
decanol distilled over. Finally, most of the dodecanol
excess was removed from the reaction mixture by vacuum
distillation. 475 g of crude product remained behind.
According to liquid chromatographic analysis (HPLC),
~he crude product contained 90.6 wt. % of
toluene-2,4-bis-carbamic acid -bis-dodecylester ~yield:
98~ of theoretical yield). The crude product was
25 recrystallized from ligroin and yielded almos~
colorless crys~als with a melting point of 82C. A
total of 425 g of 3-toluidine was detected in the
distillate.
Example 11
A mixture of 330 g of aniline and 86 g of urea was
heated to 190C over a period of 30 minutes with stir-
ring in a 2 llter round bottomed flask eq~ipped with
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~182~
- 22-
dropping funnel and a packed column. The ammonia gas
released during this time was removed through the
column and absorbed in water. After an additional l.5
hours during which the temperat:ure was raised to 205C,
liberation of ammonia was comp].eted. The apparatus was
briefly flushed with nitrogen. 800 g of decanol heated
to 200C were then added to the reaction mixture and
the mixture was heated to 220C:. A solution of 140 g
of 4,4'-diamino-diphenylmethane in 300 g of n-decanol
10 was then introduced dropwise into the reaction mixture
which was at 220C, in the course of 4 hours with stir-
ring at atmospheric pressure while aniline distilled
over the column. When all of the solution of diamino
diphenylmethane had been added~ stirring was continued
15 for an additional hour at 220C and atmospheric
pressure while aniline distilled over. The pressure
was then slowly reduced until pure decanol distilled
over. Finally, st of the decanol excess was removed
from the reaction mix~ure by vacuum distillation and
20 407 g of crude product remained behind. According to
liquid chromatographic analysis (HPLC), the crude
product contained 96.2 wt. % of diphenyl-
methane-4?4'-bis-carbamic acid-bis-decyl ester (yield:
98% of theoretical yield). Recrystallization of the
25 crude product from ethanol yielded colorless crystals
melting at 116C. A total of 327 g of aniline was de-
tected in the distillate.
Example 12
A mixture of 323 g of N,N'-dipheny~urea, 150 g of
30 4,4' diamino-dip~enylmethane, 1200 g of
2.-(2-butoxy~ethoxy)-ethanol and 1 g of dibutyl tin
oxide was heated to 210-212C with vigorous stirring in
Mo-2359
67
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a 2 liter round bottomed flask with a packed column
attached. Heating was continued at 212C and atmos-
pheric pressure for 6.5 hours while aniline was
dis~illed over the column. The temperature was then
rai~ed to 230C and distillation was continued for 30
minutes. Finally, most o~ the butoxy-ethoxy-ethanol
excess was removed from the reaction mixture by vacuum
distillation. 432 g of crude product remained behind.
According to liquid chromatographic analysis (HPLC),
the crude product contained 95.9 wt. % of diphenyl-
methane-4,4'-bis-carbamic acid-bis-[(2-butoxy-ethoxy)
-ethyl]-ester (yield: 95% of theoretical yield). A
to~al of 275 g of aniline was detected in the
distillate.
Example 13
A mixture of 350 g of aniline and 85 g of urea was
heated to 190C for 30 minutes with stirring in a 2
liter round bo~tomed flask equipped with dropping
funnel and a packed column. Ammonia gas was released
and conducted away over the column and absorbed in
water. After an additional 1.5 hours, during which the
temperature was raised to 205C, the release of ammonia
was completed. The apparatus was briefly flushed with
nitrogen. 1000 g of 2-phenoxy-ethanol heated to 200C
were then added to the reaction mixture and the mixture
was heated to 230C. 140 g of a commercial mixture of
4,4'-, 2,4'- and 2,2'-diamino-diphenylmethane and poly-
phenyl-polymethylene-polyamine having an analyzed equiv-
alent weight of 99.9 ~based on the amino group) were
then introduced dropwise with vigorous stirring over a
period of ~ hours at atmospheric pressure into the
reaction mixture which was at a temperature of 230C,
Mo-2359
- 24-
while aniline was distilled over the column. After
addition of the amines had been completed, the mixture
continued to be stirred for an additional 2 hours at
230-235C and atmospheric pressure while aniline was
distilled over. The pressure was then reduced until
pure phenoxy-ethanol distilled over. Lastly, most of
~he phenoxy-ethanol excess was removed from the
reaction mixture by vacuum distillation and 387 g of
crude product remained behind. According to analysis
by tltration (HClO~ in glacial acetic acid), this
crude product contained a total of 0.015 mol of amino
groups, which corresponded to 99% conversion of the
amino groups. The residual amount of 2-phenoxy-ethanol
in the crude produc~ was found to be 3.7 wt. % accord-
ing to separation by column chromatography using silicagel. The crude product consisted substantially of a
mixture of the carbamic acid(2 phenoxy-ethyl)-
ester corresponding to the amine put into the process,
as demonstrated by an infra-red spectroscopic
20 comparison with an authentic substance prepared from
the same amine by a different method. A total of 348 g
of aniline was detected in the distillate.
~o-2359
