CA1123000A

CA1123000A - Process for the preparation of an aromatic di- and/or polyurethane

Info

Publication number: CA1123000A
Application number: CA349,776A
Authority: CA
Inventors: Franz Merger; Friedrich Towae
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 1979-04-30
Filing date: 1980-04-14
Publication date: 1982-05-04
Also published as: ATE2000T1; EP0019109A1; JPH0114218B2; BR8002554A; JPH0246576B2; JPS55145655A; EP0019109B1; ZA802580B; JPS6425752A; DE3061318D1; US4611079A; DE2917569A1

Abstract

PROCESS FOR THE PREPARATION OF AN AROMATIC
DI- AND/OR POLYURETHANE

Abstract of the Disclosure A process for the preparation of an aromatic di-and/or polyurethane comprising the steps of A. reacting a primary aromatic di- and/or poly-amine, urea and an alcohol at temperatures of 160°C to 300°C, and B. separating the ammonia and other by-products from the aromatic di- and/or polyurethane.
One or more catalysts may be added to the react-ants to increase the reaction rate. The aromatic di- and/or polyurethanes produced are valuable end and intermediate products. They can be transferred into the corresponding isocyanates which can then be used for the preparation of polyurethanes.

Description

~ 23~
PROCESS FOR THE PREPARATION OF AN AROMATIC
DI_ AND/OR POLYURETHANE
Backqround of the Invention 1. Field of the Invention _ The invention pertains to the preparation of an aromatic di- and/or polyurethane from an aromatic di- and/or polyamine, urea and an alcoholO

2. De cription of the Prior Art On an industrial scale, N-substituted urethanes are normally produced by the reaction of alcohols with isocyanates or by the reaction of amines with chlorocarbonate. The isocyanates and chlorocarbonates used in these reactions are obtained by phosgenation of the corresponding amines or the corresponding alcohols. Houben-Weyl, Methods of Organic Chemistry, Vol. 8~ pages 137, 120 and 101, (Georg Thieme Publishers, Stuttgart, 1952). These processes are very expensive and phosgene must be used with care because of its potential danger to man and the environment.
N-arylurethanes are used as intermediates and end products. For instance, German Published Application 26 35 490 and U.S. Patent 3~919,278 disclose the use of N-sub-stituted urethanes for the manufacture of isocyanatesO
Because of their utility, many attempts have been made to develop better methods for preparing N-substituted urethanes.
These methods and their shortcomings will be discussed.
German Published Application 21 60 111 describes a process for the manufacture of N-substituted urethanes by reacting an organic carbonate with a primary or secondary .~

aromatic amine in the presence of a Lewis acid. There are several problems with this process. The conversion rates are rather low and the reaction times are long. Furthermore, N-alkylarylamines are always produced as by-products.
U~S. Patent 2,834,799 describes a process for making carbamic and carbonic esters by the reaction of urea with alcohols in the presence of boron trifluoride. The problem with this method is that the boron trifluoride is required in equimolar quantities so that at least one molecule of boron trifluoride is used per molecule of produced carbamic ester and at least two molecules of boron trifluoride are consumed per molecule o carbonic esterO This process is not only expensive, but it causes problems in the environment because the boron trifluoride is produced in the form of the H3N.BF3 adduct.
R. A. Franz et al, Journal of Organic Chemistryt Vol. 28, page 585 (1963) describe a process for making methyl-N-phenyl urethane from carbon monoxide, sulfur, aniline, and methanol. Very low yields are produced by this method; the yield does not exceed 25 percent even when there is a long reaction period.
U.S. Patent 2,409,712 describes a process for making N-alkyl and M-aryl urethanes by the reaction of monoamines with urea (either N,N'-dialkyl- or N,N'-diarylurea is used) and alcohols at temperatures of 150C to 350C under increased pressure. It should be noted that this patent only describes the manufacture of N-alkylmonourethanes and does not mention ~ ~3~

the manufacture of N,N'-disubstituted diurethanes and poly-urethanes. Furthermore, the only example given for the preparation of an N-arylmonourethane did not involve the use of an amine. Instead, the N-phenylurethane was prepared by alcoholysis of diphenyl ureas.
U.S. Patent 2,677,698 also describes a process for the manufacture of N-substituted monourethanes. In this process, the urea is initially converted into the cor-responding N,N'-disubstituted urea with monoamines, is then cleaned, and subsequently is reacted with an alcohol~ The processes described are expensive and the yields are very low. Attempts to improve the yield by improving the methods of preparing and purifying the N,N'-disubstituted ureas have been unsuccessful.
Other processes have not been successful in elimina-ting the problems described thus far. U.S. Patent 2,806,051 describes a process whereby aromatic urethanes are produced by reacting aniline with urea and alcohol at a mole ratio of 1.0:1.2:2.0 at temperatures below 200C, preferably of 120C
to 160C. Even in the preferably used temperature range, this proces~ produces only small yields of N-phenylmonourethanes if the reaction time is limited to a period which is practical in an industrial settingO In view of the problems with this process, it is not surprising that U.S. Patent 3,076,007, which describes the manufacture of N-alkyl- and N-cycloalkyl urethanes, does not incorporate the above-referenced methods in its process. It does, however, describe the reaction of ~ r ~3~

phosgene with alcohols to form chloroalkylformates, and it describes their subsequent reaction with amines to form urethanes. It also discloses the reaction of amines with ethylene carbonate to form urethanes. German Published Application 27 16 540 describes a recent variation of the process whereby dialkyl carbonates are reacted with N-acyl-amines to prepare aromatic amines.
None of the references cited discloses the prepara-tion of aromatic di- and/or polyurethanes by reacting aromatic diamines with urea and alcohol at temperatures of 160C to 300C. The reaction temperatures utilized in UOS. Patent 2,806,051 are lower and it appears that only aromatic mono-amines are used in this process. If one uses aromatic di-amines in the process as described, one obtains high yields of a product in the form of a precipitate with a structure almost identical to the polyureas which are formed from diamines and polyisocyanates.
It is surprising that aromatic di- and/or poly-urethanes can be produced in one process stage with good yields by reacting aromatic diamines with urea and alcohol at tempera~ures of 16~C to 300C, Prior teachings indicate ~hat corresponding N,~'-diarylureas are obtained from aromatic monoamine~ and urea: for example, N,N'-diphenylurea is obtained from aniline and urea. Prior art also teaches that~
although urea and alcohol may react to produce urethanes, they continue to react to form N,N'-disubstituted arylureas in the presence of aromatic amines. See Houben-Weyl, Methods of Organic Chemistry, Vol. 8~ pages 151, 140, and 161 (Georg Thieme Publishers, Stuttgart, 1952). These side reactions decrease the yield of the desired product.
Furthermore, German Patent 896 412 indicates that high molecular, spinnable condensation products may be produced from urea and diamines at temperatures above 100C.
U.S. Patent 2 r 181~663 and U.S~ Patent 2,568,885, for instance, disclose that high molecular polyureas with molecular weights of 8000 to 1U,000 and greater, may be produced when di-urethanes are condensed with diamines at temperatures ofapproximately 150C to 300C. Moreover, mono- and poly-urethanes can furthermore be split thermally into isocyanates, alcohols and possibly olefins, carbon dioxide, urea and carbodiimide, and these products can be split into products such as biurets, allophanates, isocyanurates, poly-carbodiimides, and others. See The Journal of the American Chemical Society, Vol. 80, page 5495 (1958) and Vol. 48, page 1946 (1956).
In view of the problems disclosed in the prior art, i~ was surprising that our process~ which involved very similar reaction conditions, would result in di~ and/or polyurethane with very good yields. It was particularly surprising because when diurethanes were prepared from the products mentioned in the previous paragraph according to the reaction conditions of our invention, good yields did no~
result.

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Summary of the Invention The purpose of this invention was to produce an aromatic di- and/or polyurethane from readily available raw materials in one reaction stage under economically justifiable conditions with good yields. The use of strongly toxic raw materials such as phosgene, carbon monoxide, or catalysts which are toxic and form toxic compounds during the reaction, such as hydrogen sulfide~ was to be avoided.
The problem was solved by developing a process for the preparation of an aromatic di- and/or polyurethane comprising the steps of A. reacting a primary aromatic di- and/or polyamine with urea and an alcohol at temperatures of 160C to 300C, and B. separating the ammonia and other by-products from the aromatic di- and/or polyurethane.
One or more catalysts may be added to the reactants in order to increase the reaction rate~
The reaction may be illustrated by the following equation:

AR-(N~)n ~ n H2NCON~2 + n HOR - > AR-(NHCOOR)n + 2nNH3 The aromatic di- and/or polyurethanes produced according to the process of this invention are valuable end and intermediate products. They are used, fQr instance, as pesticides. As intermediate products~ they are used as components for polycondensation and polymer systems and, in particular, they are transformed into the corresponding di-and/or polyisocyanates by removal of the alcohol. The di-and/or polyisocyanates can be used in the manufacture of polyurethanes.
Description of the Preferred Embodiments In order to prepare the aromatic di- and/or poly-urethanes in accordance with the process of this invention, a primary aromatic di- and/or polyamine and an alcohol are reacted with the urea in such quantities that the ratio of amino groups of the aromatic di- and polyamines to urea to hydroxyl groups of the alcohols i5 1:0.8 10:5-100, preferably 1:0.9-7:5-50 and in particular, 1:1-5:10-30~
The reaction preferably is carried out in the presence of excess alcohol as a solvent and reaction agent at temperatures of 160C to 300C and at normal pressures, or under reduced or increased pressure. One or more catalysts may be added to the reaction mixture in order to increase the reaction rate. It has proven to be advantageous to immedi-ately remove the resultant ammonia from the reaction mixture, for instance, by means of distillation.
Unsubstituted or substituted primary aromatic di-and/or polyamines or their mixtures may be reacted with the urea and alcohol to prepare the polyurethane. Specific examples include: aromatic diamines such as 1,3- and 1,4- -diamino benzene; 1,3-diaminobenzene substituted in the 2 and/or 4 position by nitro, methyl5 ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, methoxy, ethoxy~
n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, 3~

tert-butoxy groups or halogen atom, preferably fluorine or chlorine; or 1,4-diaminobenzene, 1,5- and 1,8-diamino-naphthalene, 4,4'-diaminodiphenyl, 2,2'-, 2,4'- and 4,4' diaminodiphenylmethane and the corresponding isomer mixtures thereof, all of which may be substituted in the 2 position by a nitro, methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy group or a halogen atom, preferably a fluorine or a chlorine atom;
and polyphenylpolymethylene pQlyamines as well as mixtures of diaminodiphenyl methanes and polyphenylpolymethylene poly-amines which are produced in accordance with familiar methods by the condensation of aniline and formaldehyde in the presence of preferably mineral acids as catalysts and which may be substituted with any of the above identified groups or atoms.
Preferably used as aromatic diamines, however~ are 2,4- and 2,6-diaminotoluenep as well as the corresponding isomer mixtures, 2,21-S 2,4'- and 4,4'-diaminodiphenylmethane and the corresponding isomer mixtures, and 1,5-diamino-naphthalene; preferably used as polyamines are mixtures of diaminodiphenylmethane and polyphenylpolymethylene polyamines.
Any desired unsubstituted or substituted primary or secondary aliphatic alcohol or aromatic-aliphatic alcohol, ac well as mixtures thereof, may be used as alcohols for the process according to this invention. Examples include primary aliphatic monoalcohols having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, ~uch as methanol, ethanol, propanol, n-butanol, isobutanol, 2- and 3-methylbutanol, neopentyl alcohol, pentanol, 2-methylpentanol, n-hexanol, 2-ethyl-hexanol, n-heptanol, n-octanol, n-nonanol, n-decanol, n-dodecanol, 2-phenylpropanol and benzyl alcohol; and secondary aliphatic and cycloaliphatic monoalcohols having 3 to 15 carbon atoms, preferably 3 to 6 carbon atoms, such as iso-propanol, sec~butanol, sec-isoamyl alcohol, cyclopentanol, cyclohexanol, 2,3~ or 4-methylcyclohexanol, and 4-tertiary-butylcyclohexanol. Preferably used are the monoalcohols9 methanol, ethanol~ propanol, butanol, isobutanol, 2- and 3-methylbutanol, 2-ethylbutanol~ pentanol, 2-methylpentanol/
hexanol, 2-ethylhexanol, heptanol, octanol, and cyclohexanol.
As already indicated, the reaction preferably is carried out with excess alcohol so that the alcohol functions as a reaction component and simultaneously as a solvent.
Instead of alcohol, however, mixtures of alcohols and other organic solvents which are inert under the reaction conditions may al SG be used as solvents.
According to this invention, the aromatic di- and/or polyurethanes, preferably the diurethanes, are appropriately produced in the absence of catalysts since the reaction normally takes place in economically acceptable reaction times and with good yields. This avoids costly cleaning operations for removing the catalysts from the resultant end products.
If catalysts are used in order to increase the rate of reaction, preferably at low temperatures, they should be _9_ used in quantities of 0.1 to 20 percent by weight, preferably 0.5 to 10 percent by weight, and in particular 1 to 5 percent by weight relatlve to the weight of the primary di- or poly-amine. Suitable catalysts are inorganic or organic compounds containing one or more, preferably one, cation of metals of the groups IA, IB, IIA, IIB, IIIA, IIIB, IVA, IV~, VA, VB, VIB, VIIB and VIIIB of the periodic ~ystem defined in ac-cordance with the Handbook of Chemistry and Physics, (14th edition, Chemical Rubber Publishing Company, 2310 Superior Avenue N.W~, Cleveland, Ohio). These compounds include, for instance, halides such as chlorides and bromides, sulfates, phosphates, nitrates, borates~ alcoholates, phenolates, sulfonates, oxides, oxidehydrates, hydroxides, carboxylates, chelates, carbonates, and thio- or dithiocarbamates~ The compounds should contain cations of any of the following metals: lithium, sodium, potassium, magnesium, calcium, aluminum, gallium, tin, lead, bismuth, antimony, copper, silver, gold, zinc, mercury, cerium, titanium, vanadium, chromium, molybdenum, manganese, iron, cobalt and nickel.
Preferably used are the cations of lithiumr calcium, aluminum, tin, bismuth, antimony, copper, zinc, titanium, vanadium, chromium, molybdenum, manganese, iron and cobalt. Without any recognizable marked drawbacks, the catalysts may also be used -in ~he form of their hydrates or ammoniates.
Examples of typical catalysts include the following compounds: lithium methanolate, lithium ethanolate, lithium 3~s~

propanolate, lithium butanolate, sodium methanolate, potas-sium-tertiary butanolate, magnesium methanolate, calcium methanolate, tin-(II)-chloride, tin (IV)--chloride, lead acetate, lead phosphate, antimony-(III)-chloride, antimony-(V)-chloride, aluminum isobutylate, aluminum trichloride, bismuth-(III)-chloride, copper-(II)-acetate, copper-(II)-sulfate, copper-(II)-nitrate, bis(triphenylphosphineoxido)-copper-(II)-chloride, copper molybdate, silver acetate, gold acetate, zinc oxide, zinc chloride, ~inc acetate, zinc acetonylacetate, zinc octoate, zinc oxylate, zinc hexylate, zinc benzoate, zinc undecylenate, cerium-(IV)-oxide, uranyl acetate, titanium tetrabutanylate, titanium tetrachloride, titanium tetraphenolate, titanium naphthenate, vanadium-(III)-chloride, vanadium acetonylacetate, chromium-(III)~
chloride, molybdenum-(VI)-oxide, molybdenum acetylacetonate, tungsten-(VI)-oxide, manganese-(II)~chloride, manganese (II)-acetate, manqanese-(IIIj-acetate, iron-(II)-acetate, iron-(II)-acetate, iron phosphate, iron oxylate, iron-(III)-chloride, iron-(III)-bromide, cobalt acetate, cobalt chloride, cobalt sulfate, cobalt naphthenate, nickel chloride, nickel acetate and nickel naphthenate as well as their mixtures.
The reaction takes place at temperatures o 160C to 300C, preferably of 180C to 250C, and particularly from 185C to 230C; and at pressures of 0.1 bar to 120 bars, preferably 0.5 bar to 60 bars, and in particular from 1 bar to 40 bars. The reaction times, which are appropriate for the corresponding temperature ranges~ are 0.1 hour to 50 hours, preferably 0.5 hour to 20 hours. Wi.th a given temperature, ~ ~ 2~

the reaction is then prefera~ly carried out under a pressure which allows the resultant ammonia to be selectively distilled out of the reaction mixture. The corresponding values may be taken from tables of physical characteristic data for ammonia and alcohols.
One effective way of preparing the aromatic di-and/or polyurethanes is to mix the reactants in the cor-responding mole ratios, in the presence or absence of cata-lysts, in a pressurized or unpressurized reaction vessel equipped with a device for separating the ammonia, and then heat the mixture. The resulting ammonia can be separated after the reaction has been completed. Preferably, however, it is distilled off during the reaction. It may be advanta-geous, particularly in the case of the reaction of low molec-ular weight alcohols under pressure, to separate the ammonia by using a stripping agent which is inert under the reaction conditions, such as a gas like nitrogen.
A particularly advantageous method of preparing the aromatic di- and/or polyurethanes which, as a rule, results in a considerable reduction of the reaction time, is described as follows: ~1) The primary aromatic di- and/or polyamines, the urea, and the alcohol are initially reacted in a ratio of the amino groups of the amines to urea to hy~roxyl groups of the alcohol of 1:1.5-3:2-10, preferably 1-1~5-2-4-8 for 0.5 hour to 3 hours, preferably 0.5 hour to 2 hour~. (2) Subsequently, additional alcohol is added to the reaction mixture in an amount such that 10 to 30, preferably 15 to 30 moles of '~,f~'3~

alcohol are present per amino group of the amine and such ~hat the reaction is completed in a total time period of 4 hours to 20 hours, preferably 4 hours to 10 hours. (3) Thereafter, before or after removing the catalyst and/or filtering out solid materials, the di- and/or polyurethanes are isolated from the resulting reaction mixture. This may be done, for instance, by completely distilling off the alcohol and/or the solvent as well as any O-alkyl carbamates which are formed as by-products, by partially distilliny off the alcohol and crystallization, by crystallization, or by precipitation with or transcrystallization from other solvents.
The parts referred to in the specific examples which follow are relative to weight. The elementary compositions and structures were confirmed by elementary analysis, mass spectrometry, as well as infra-red and nuclear magnetic resonance spectra.

~ ~3~

Example 1 In a reaction vessel, 10 parts of 4,4'-diaminodi-phenylmethane with 15.2 parts of urea in 195 parts of n-octanol are heated to a reflux temperature of approximately 195C for 5 hours and the resulting ammonia is simultaneou~ly removed by distillation. The mixture is allowed to cool and the crystallized 4,4'-bis(octoxycarbonylamino)diphenylmethane (C31H~6OgN2~ molecular weight 510) is removed by filtration.
The yield is 24.2 parts ~94.0 percent of theory) and the melting point is 118C 119C.
~e~
In a reaction vessel, 12~2 parts of 2,4-diamino-toluene with 60 parts of urea in 390 parts of n-octanol are heated to a reflux temperature of approximately 195C for 7 hours and the resultant ammonia is simultaneously removed by distillation. Following this, the reaction solution is subjected to fractional distillation up to a sump temperature of 180C with the excess octanol and unsubstituted carbamic ester being reclaimed in this sequence. In the resultant residue, 38.6 parts of 2,4-bis(octoxycarbonylamino)toluene (88.9 percent of theory)~ C2sH42O4N2 (molecular weight 434) is detected by using the external standards method of high pressure liquid chromatography~ The melting point (from cyclohexane) is 68~C-70~C~
~E~
In a reaction vessel, 5 parts of 4,4'-diaminodi phenylmethane with 6.1 parts of urea and 46 parts butanol are ~ 23~

heated to boiling with a pressure of 7 bars to 8 bars being adjusted in the reactor via a pressure valve so that the boiling temperature of the butanol i5 approximately 20QC.
Using 25 liters per hour of nitrogen per liter of reaction mixture as a stripping agent, the ammonia formed during the reaction is removed by distillation. The product is allowed to cool, is depressurized and the solvent is concentrated.
This results in the crystallization of 8.4 parts (83.6 percent of theory) of 4,4'-bis(butoxycarbonylamino)diphenylmethane, C23H30O~N~ (molecular weight 398)~ The melting point is 91 C-95C.
In addition to the starting product, 4-amino~
(butoxycarbonylamino)diphenylmethane is also found in the reaction solution.

~.
In a reaction vessel, 12.2 part of 2,4-diamino-toluene with 14 parts of urea and 200 parts of cyclohexanol are heated to boiling for 10 hours with a pressure of 2 bars to 3 bars being adjusted in the reactor via a pressure valve so that the boiling temperature of cyclohexanol is approxi-mately 200C. Using 25 liters per hour of nitrogen pex liter of reaction mixture as a stripping agent~ the ammonia formed during the reaction is removed by continuous distillation.
After cooling, the mixture is analyzed by means of high pressure liquid chromatography using the external standard methodO This showed that 18 parts of 254~bis(0ctoxycarbonyl-amino)toluene (48.1 percent of theory) and 12.4 parts of a -15~

mixture consisting of 2-amino-4-(octoxycarbonylamino)toluene and 4-amino~2-(octoxycarbonylamino)toluene (50.0 percent of theory) are formed so that the total yield of urethanes is 98.1 percent.
Example 5 In a reaction vessel, 8 parts of 1,5-diamino-naphthaline with 18 parts of urea in 150 parts of n-octanol are heated to reflux temperature o~ approximately 195C for 10 hours and the resulting ammonia is simultaneously sepaxated.
10 ~he product i5 allowed to cool. Upon cooling, a mixture of -unreacted 1,5-diaminonaphthaline and 1,5-bis(octoxycarbonyl-amino)naphthaline, C2gH42O4N2 (molecular weight 470), will crystallize. After transcrystallizing from acetic ester, 15 parts of 1,5-bis(octoxycarbonylamino)naphthaline, having a melting point of 69C-71C (64.3 percent of theory), are obtained. The mother liquor still contains 1,5-diamino naphthaline and 1-amino-5-(octoxycarbonylamino)naphthaline.
Example_6 In a reaction vessel, 8 parts of 1,5-diamino-naphthaline with 12 parts urea in 57 parts ethanol are heatedto boiling for a period of 18 hours at a pressure of 22 bars to 24 bars. The pressure is adjusted in the reactor by a pressure valve so that the boiling temperature of ethanol is approximately 190C. Using 30 liters of nitrogen per hour per liter of reaction mixture as a stripping agent, the ammonia formed during the reaction is continuously removed by dis-tillation. The reaction mixture i~ cooled, depressurized and the alcohol is removed by distillation= This results in the crystallization of 11.7 parts (76.5 percent of theory) of 1,5-bis(ethoxycarbonylamino)naphthaline~ C1~H~gO4N~
(molecular weight of 302). The melting point is 222C to 2~4C.
Examyle 7 In a reaction vessel, 5 parts of a commercially available mixture of 2,2'-, 2,4'- and ~,4'-diaminodiphenyl-methane and polyphenylpolymethylene polyamines with 4 parts of urea are heated to boiling in 93 parts of n-octanol. The mixture is allowed to cool, excess octanol and resulting carbamic octyl esters are removed by distillation up to a temperature of 180C, and the residue is mixed with 50 parts of cyclohexane. A powdery precipitate is obtained which is separated from the solution. The analysis of the precipitate !
using high pressure liquid chromatography, shows that 706 parts of a mixture were formed consisting of 2,2'-, 2,4'- and

4,4'-bis(octoxycarbonylamino)diphenylmethane as well as polyphenylpolymethylenepolyoctyl urethanes.
Comparison Exam~e (The method disclosed in U.S. Patent 2,806,051 was follcwed except an aromatic diamine was used instead of an aromatic monoamine.) In a reaction vessel, 13 parts of 4,4'-dlaminodiphenylmethane with 7.~ parts of urea and 15 parts of n-butanol are heated to boiling. After approximately 45 minutes, the reaction mixture begins to appear cloudy.
During further reaction, considerable quantities of an in-soluble solid material precipitate, which is no longer dissolved within the course of an additional 90 hours. Based on infra-red analysis, a polyurea structure must be ascribed to the resultant solid material.
Example 8 Example S was duplicated with an exception that an additional 0.1 part of sodium methylate was added to the - -reaction mixture as catalyst. Obtained are 18.7 parts of 1,5-bis(octoxycarbonylamino)naphthaline (78.6 percent of theory), C28H424N21 (molecular weight ~70), having a melting point of 71C to 72C.
Example 9 In a reaction vessel, 12.2 parts of 2,4-diamino-toluene with 32 parts of urea in 104 parts of n-octanol are heated to boiling. After 6n minutes, 416 parts of n~octanol are added to the reaction mixture and the mixture is boiled for another 4 hours. Durin~ the entire reaction; ammonia is removed continuously by distillation. After completed re-- action, excess n-octanol and carbamic octyl ester, produced as a by-product, are removed by fractional distillation up to a sump temperature of 190C~ Using high pressure liquid chromatography according to the external standards method, 40.2 parts (92.6 percent of theory) of 2~4-bis(octoxycarbonyl-amino~toluene are shown in the resultant distill~tion residue.

~ .
In a reaction vessel, 6.1 parts of 2,4-diamino-toluene with 15 parts of urea and 1804 parts of ethanol are heated to boiling with a pressure of 24 bars to 25 bars. The ~ 2~

pressure is adjusted in the reactor via a pressure valve so that the boiling temperature of the ethanol is approximately 195C. After a reaction period of 45 minutes, an additional 74 parts of ethanol are added to the reaction mixture. Using 30 liters per hour of nitrogen per liter of reaction mixture, the ammonia formed during the reaction is continuously removed by distillation. The reaction mixture is then cooled and depressurizedO Upon cooling in an ice-sodium chloride mixture, 7.9 parts (59.4 percent of theory) of 2,4-bis(ethoxycarbonyl-amino)toluene, C13H1gO4N2 (molecular weight 266), crystal-lize having a melting point of 10gC to 110C. With the aid of high pressure liquid chromatography, using the external standard method, 3.2 parts of 2,4-bis(ethoxycarbonylamino)-toluene ~24~1 percent of theory~ and 1,4-parts of a mixture of 2-amino-4-(ethoxycarbonylamino)toluene and 4-amino-2-(ethoxy-carbonylamino)toluene (14.4 percent of theory~ are shown in the mother liquor. Thus, the total yield of urethanes is 97.9 percent.
~ ,~
In a reaction vessel, 6.1 parts of 2,4-diamino-toluene with 12 parts of urea and 18.4 parts of ethanol are heated to boiling with a pressure of 17 bars to 18 bars. The pressure is adjusted in the reactor via a pressure valve so that the boiling temperature of the reaction mixture is approximately 180C. Using 5 liters of nitrogen per hour per liter of reaction mixture, the ammonia formed during the reaction is removed by continuous distillation~ With the aid _1 9--of high pressure liquid chromatography, according to the external standard method, 6.2 parts of 2,4-bis(ethoxycarbonyl-amino)toluene are shown to be in the reaction solution after 5 hoursO This corresponds to a 79.3 percent conversion of 2,4-diaminotoluene and a yield of diurethane of 58.8 percent with a volume-time yield of 34.0 grams per liter per hour.
Examples 12 to 16 The process of Example 11 was duplicated with the exception that 0.1 part of the catalyst was added to the reaction mixture.
The catalysts used, the reaction times, and the resulting yields are summarized in the following Table.

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a o g I ~ ~ (a u ~ c) a~
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Claims

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. A process for the preparation of an aromatic di-and/or polyurethane comprising the steps of A. reacting a primary aromatic di- and/or polyamine with urea and an alcohol at temperatures of 160°C to 300°C, and B. separating the ammonia and other by-products from the aromatic di- and/or polyurethane.

2. The process of claim 1 carried out in the presence of one or more catalysts.

3. The process of claim 1 or 2 wherein the re-actants are present in such quantities that the ratio of amino groups of the primary aromatic di- and/or polyamines to urea to hydroxyl groups of the alcohol is 1:0.8-10:5-100.

4. The process of claim 1 or 2 wherein the ammonia by-product is continuously separated from the system as it is formed.

5. The process of claim 1 or 2 wherein the reaction is carried out at pressures of 0.1 bar to 120 bars.

6. The process of claim 1 wherein the aromatic diamines are selected from the group consisting of 2,4- and 2,6-diaminotoluene, the corresponding isomer mixtures thereof, 1,5-diamino naphthalene, 2,2'- 2,4'- and 4,4'-diaminodi-phenylmethane and the corresponding isomer mixtures thereof.

7. The process of claim 1 wherein the aromatic polyamines are mixtures of diaminophenylmethanes and poly-phenylpolymethylene.

8. The process of claim 1 or 2 wherein the alcohol is selected from the group consisting of methanol, ethanol, propanol, butanol, isobutanol, 2- and 3-methylbutanol, 2-ethyl butanol, pentanol, 2-methylpentanol, hexanol t 2-ethylhexanol, heptanol, octanol, cyclohexanol and mixtures thereof.

9. The process of claim 2 wherein the catalyst is a compound containing, in bonded form, one or more cations of metals selected from the group consisitng of groups IA, IB, IIA, IIB, IIIA, IIIB, IVA, IVB, VA, VB, VIB, VIIB and VIIIB of the periodic system.

10. The process of claim 1 or 2 comprising A. condensing the reactants in a ratio of amino groups of the amines to urea to the hydroxyl groups of the alcohol of 1:1.5-3:2-10 for 0.5 hour to 3 hours, and B. adding alcohol to the reaction mixture in an amount such that the ratio of amino groups of the amines to the hydroxyl groups of the alcohol is 1:10-30 and such that the reaction is thereupon completed.