CA1105480A - Process for the preparation of diphenylmethane mono and dicarbamates and polymethylene polyphenyl carbamates by the acid rearrangement of an (alkoxycarbonyl)phenylamino-methylphenyl compound - Google Patents

Process for the preparation of diphenylmethane mono and dicarbamates and polymethylene polyphenyl carbamates by the acid rearrangement of an (alkoxycarbonyl)phenylamino-methylphenyl compound

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CA1105480A
CA1105480A CA306,259A CA306259A CA1105480A CA 1105480 A CA1105480 A CA 1105480A CA 306259 A CA306259 A CA 306259A CA 1105480 A CA1105480 A CA 1105480A
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Prior art keywords
acid
process according
per cent
compound
alkoxycarbonyl
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French (fr)
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Edward T. Shawl
John G. Zajacek
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Atlantic Richfield Co
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Atlantic Richfield Co
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C269/00—Preparation of derivatives of carbamic acid, i.e. compounds containing any of the groups, the nitrogen atom not being part of nitro or nitroso groups
    • C07C269/06—Preparation of derivatives of carbamic acid, i.e. compounds containing any of the groups, the nitrogen atom not being part of nitro or nitroso groups by reactions not involving the formation of carbamate groups
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C265/00—Derivatives of isocyanic acid
    • C07C265/14—Derivatives of isocyanic acid containing at least two isocyanate groups bound to the same carbon skeleton
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C269/00—Preparation of derivatives of carbamic acid, i.e. compounds containing any of the groups, the nitrogen atom not being part of nitro or nitroso groups
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C269/00—Preparation of derivatives of carbamic acid, i.e. compounds containing any of the groups, the nitrogen atom not being part of nitro or nitroso groups
    • C07C269/04—Preparation of derivatives of carbamic acid, i.e. compounds containing any of the groups, the nitrogen atom not being part of nitro or nitroso groups from amines with formation of carbamate groups
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C271/00—Derivatives of carbamic acids, i.e. compounds containing any of the groups, the nitrogen atom not being part of nitro or nitroso groups
    • C07C271/06—Esters of carbamic acids
    • C07C271/08—Esters of carbamic acids having oxygen atoms of carbamate groups bound to acyclic carbon atoms
    • C07C271/10—Esters of carbamic acids having oxygen atoms of carbamate groups bound to acyclic carbon atoms with the nitrogen atoms of the carbamate groups bound to hydrogen atoms or to acyclic carbon atoms
    • C07C271/12—Esters of carbamic acids having oxygen atoms of carbamate groups bound to acyclic carbon atoms with the nitrogen atoms of the carbamate groups bound to hydrogen atoms or to acyclic carbon atoms to hydrogen atoms or to carbon atoms of unsubstituted hydrocarbon radicals
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C271/00—Derivatives of carbamic acids, i.e. compounds containing any of the groups, the nitrogen atom not being part of nitro or nitroso groups
    • C07C271/06—Esters of carbamic acids
    • C07C271/08—Esters of carbamic acids having oxygen atoms of carbamate groups bound to acyclic carbon atoms
    • C07C271/10—Esters of carbamic acids having oxygen atoms of carbamate groups bound to acyclic carbon atoms with the nitrogen atoms of the carbamate groups bound to hydrogen atoms or to acyclic carbon atoms
    • C07C271/16—Esters of carbamic acids having oxygen atoms of carbamate groups bound to acyclic carbon atoms with the nitrogen atoms of the carbamate groups bound to hydrogen atoms or to acyclic carbon atoms to carbon atoms of hydrocarbon radicals substituted by singly-bound oxygen atoms
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C271/00—Derivatives of carbamic acids, i.e. compounds containing any of the groups, the nitrogen atom not being part of nitro or nitroso groups
    • C07C271/06—Esters of carbamic acids
    • C07C271/08—Esters of carbamic acids having oxygen atoms of carbamate groups bound to acyclic carbon atoms
    • C07C271/26—Esters of carbamic acids having oxygen atoms of carbamate groups bound to acyclic carbon atoms with the nitrogen atom of at least one of the carbamate groups bound to a carbon atom of a six-membered aromatic ring
    • C07C271/28—Esters of carbamic acids having oxygen atoms of carbamate groups bound to acyclic carbon atoms with the nitrogen atom of at least one of the carbamate groups bound to a carbon atom of a six-membered aromatic ring to a carbon atom of a non-condensed six-membered aromatic ring
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C271/00—Derivatives of carbamic acids, i.e. compounds containing any of the groups, the nitrogen atom not being part of nitro or nitroso groups
    • C07C271/06—Esters of carbamic acids
    • C07C271/40—Esters of carbamic acids having oxygen atoms of carbamate groups bound to carbon atoms of six-membered aromatic rings
    • C07C271/42—Esters of carbamic acids having oxygen atoms of carbamate groups bound to carbon atoms of six-membered aromatic rings with the nitrogen atoms of the carbamate groups bound to hydrogen atoms or to acyclic carbon atoms
    • C07C271/44—Esters of carbamic acids having oxygen atoms of carbamate groups bound to carbon atoms of six-membered aromatic rings with the nitrogen atoms of the carbamate groups bound to hydrogen atoms or to acyclic carbon atoms to hydrogen atoms or to carbon atoms of unsubstituted hydrocarbon radicals

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  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

PROCESS FOR THE PREPARATION OF DIPHENYLMETHANE
MONO AND DICARBAMATES AND POLYMETHYLENE POLYPHENYL
CARBAMATES BY THE ACID REARRANGEMENT OF AN
(ALKOXYCARBONYL)PHENYLAMINOMETHYLPHENYL COMPOUND
ABSTRACT OF THE DISCLOSURE
Diphenylmethane mono and dicarbamates and poly-methylene polyphenyl carbamate homologs and derivatives of these compounds are produced by the protonic or Lewis acid catalyzed rearrangement of an (alkoxycarbonyl)phenyl-aminomethylphenyl compound having the general formula including the higher homologs of such compounds, wherein x, y and z, which are different on the ring, are an alkyl group having from 1 to 3 carbon atoms, an -NHCOOR, -CH2ArNHCOOR or -N(COOR)CH2Ar group; x, y and z may also be at least one hydrogen; R is a 1 to 3 carbon alkyl group and Ar is phenyl which may be substituted with a 1 to 3 carbon atom alkyl group.

1.

Description

The present invention relates to a process for the preparation of esters of aromatic carbamic acids (urethanes) particularly diphen~Lmethane dicarbamates and related higher homologs and derivatives, by the acid catalyzed rearrangement of an (alkoxycarbonyl)phenylaminomethylphenyl compound such as 2-[(ethoxycarboxyl)phenylaminomethyl~phenylcarbamic acid, alkyl esters.
BACKGROU~3 OF THE I~ ~ NTION

.. _ _ . . _ . ...
Polymeric aromatic carbamic acid esters (poly-urethanes) such as diphenylmethane dicarbamates and the related higher homologs polymethylene polyphenyl carbamates have become increasingly important products particularly, for use in the preparation of the commercially valuable diphenylmethane diisocyanates and mixtures o~ diisocyanates and the polyisocyanates by the decomposition of such polymeric aromatlc carbamic acid esters in a suitable solvent as shown in Rosenthal et al, U.S. Patents Nos.
3,962,302, June o, 1976 and 3,-919,279, November llg 1975.
23 ~t the present time there is no known success.ul co~ercial method for the direct preparation of polymeric aromatic esters of carbamic acid. ~le corresponding di-phenylmethane diisocyanates and polyisocyanates, available commercially, are largely produced by the phosgenation of mi~tures of diamlnes and polyamines obtained by the con-censation of aniline and formaldehyde w-Lth catalytic quant~tLes of a mineral acid, as for example, disclosed in the Pistor et 21, UOS. Patent ~o. 4,014,914 A proposed prior art process :f or ~he preparation o~ polymeric aromatic carbamic acid esters (pol~Jurethanes) îs disclosed in Klauke et al, U.S. Patent No. 2,946,768 and involves the condensation of aryl carbamic acid esters with carbonyl compounds in a dilute aqueous acid condensation medium. However, in such process the carbonyl compound such as ~ormaldehyde tends to react at the nitrogen of the carbamate to produce along with desired polyurethanes, vary ing amounts, i.e., generally between 15 per cent and 50 per cent by weight, of undesirable (alkoxycarbonyl)phenyl-aminomethylphenyl compounds which includes the various dimers, trimers~ tetramers, etc. of such compounds (also re~erred to herein as "N~benzyl" compounds). Attempts to prepare mono or diisocyanates and polyisocyanates or to otherwise use the mixture containing the undesired N-benzyl compounds, which cannot be converted to an isocyanate by pyrolysis, and polyurethanes presents many problems since there is no known method ~or separating the polyurethanes ~rom the N-benzyl impurities.
SUMMARY OF THE INVENTION
This invention relates to a process for the pre-paration of diphenylmethane mono and dicarbamates and the higher molecular weight homologs, polymethylene polyphenyl carbamates, which comprises catalytically rearranging an (alko~ycarbonyl)phenylaminomethylphenyl compound (N benzyl compound) with a particular acid medium. More specifically, the present invention concerns a method ~or the preparation o~ the carbamates by the catalyzed rearrangement o~ the N-benzyl compounds produced, in addition to urethanes3 as side products by the condensation o~ lower alkyl esters o~
phenyl carbamic acid with carbonyl compounds, such as formaldehyde, in the presence of an aqueous acid solution 3.

$~
as described for example in the aforementioned U.S.Patent
2,946,768 and incorporated herein by re~erence. The product mixture produced by such condensation process containing diurethanes and polyurethanes, N-benzyl compounds, unreacted alkylphenylcarbamates and other by-products such as amines may be contacted a-t temperatures of from about 50C. to 170C. with a protonic acid medium having a strength at least equal to a 75 per cent sulfuric acid such as concen-trated sulfuric acid or an acid medium comprising a Lewis acid having a concent~ation of at least 0.5 per cent by weight based on the total reactlon mixture, while maintaining a minimum amount of water in the system~ to catalytically convert or rearrange said N~benzyl compounds to the desired mono-, di- and polyurethanes. Alternatively, the unreacted alkylphenylcarbamate may be removed from the mixture by~
f'or example, vacuum distillation prior to treatment. The acid rearrangement of the N-benzyl compounds resulting f'rom other methods oP preparation, as hereinafter described, is also contemplated by the method of' the present invention.
~0 It is an object of` this invention theref'ore to provide a process for the preparation of diphenylmethane mono and dicarbamates and the related polymethylene polyphenyl carbamates in high yield by the conversion or rearrangement of (alkoxycarbonyl)phen~laminomethylphenyl compounds employ-ing a suitable protonic or Lewis acid medium as a catalyst.
It is another object of this invention to provide a process for the acid catalyzed conversion or rearrangement of (alkoxycarbonyl)phenyIaminomethylphenyl compounds formed during the preparation of di- and higher polymeric carbamic acid esters by the dilute aqueous acid condensation of N-aryl carbamic acîd esters such as ethylphenyl carbamate with a car-bonyl compound to -the usef'ul di- and polyurethane compounds.
~.

These and other objects and advantages of this invention will become apparent ~rom the description o~
the -.nvention which follows and from the claims.
DESCRIPTIGN 3F THE IN~ENTION
_ In accordance with the present invention, an (alkoxycarbonyl)phenylaminomethylphenyl compound having the general formula COOR
x ~ N - CH2 ~ x y z z y including the higher homologs of compounds~ wherein x, y and z, which are dif~erent on the ring~ are an alkyl group having from 1 to 3 carbon atoms, an NHCOOR, -CH2ArNXCOOR
or -N(COOR)CH2Ar group; x, y and z may also be at least one hydrogen; R is a l to 3 carbon alkyl group and Ar is phenyl which may be substitu-ted with a l to 3 carbon atom alkyl group, is contacted at temperatures of from about 50C. to 170C~, pre~erably under atmospheric pressure, with a catalytic amount of a protonic acid medium having the strength of at least the magnitude of a 75 per cent sul~uric acid, or with a Lewis acid medium having a con-centration of at least 0.5 per cent by weight based on the total reaction mixture, with or without the addition of an inert solvent, to catalytically convert or rearrange the (alkoxycarbonyl)phenylaminomethylphenyl compound mixture to mono or dicarbamates and polymethylene polyphenyl car-bamates and derivatives~ Tke preparation o~ a diphenyl-methane dicarbamate~ diethyl ester, ~or example, is carried out according to the following po~tulated equation employing a 2-~(ethoxycarbonyl)phenylaminomethyl]phenylcarbamic acid, ethyl ester:

N _ CH2 ~ Ac d NHCOOC~Hs 2[(ethoxycarbonyl)phenylaminometh~1~phenylcarbamic acid~ ethyl ester ~ CH2 {;} NEICOOC2~I5 2~4'-methylenebis(phenylcarbamic acid), diethyl ester~ (diphenylmethane-2,4 ! ~dicarbamate, diethyl The acid catalyzed rearrangement react~on may be carried out in any suitable reactor which is generally .e~uipped with a means for agitation. A general procedure is to charge the N-benzyl compounds together with the protonic or Lewis acld catalyst and optionally a solvent into the reaction vessel and then heat the mixture to the desired temperature for the appropriate period. The reaction may be carried out batchwise or as a continuous process and the order of addition o~ the materials may be varied to suit the particular apparatus employed... The reaction prod-ucts are recovered and treated by any conventional method such as extraction of the acid medium with water or neutraliza-tion with a base and the.separation o~ the resulting phases and distillation to remove any solvent employed, or ~ilter-ing to remove the catalyst.
The (alkoxycarbonyl)phenylamirlomethylphenyl compounds whlch may be converted or rearranged by the process of the present invention and characterized by the general ~ormula above include~ for example, those compounds which may conform to the following ~ormulae wnerein R is an alkyl group containing ~rom 1 to 3 carbon atoms:

?

OOR ~

ethyl N-benzylphenylcarbamate COOR
N - CH2 ~

NHCOOR and ~ N - CH2 ~ NHCOOR
2- and 4-r(alkoxycarbonyl)phenylaminomethyl]phenylcarbamic acid, alkyl ester respectively, COOR
N - CH2 ~ NHCOOR

CH2 ~ NHCOOR
4-[(alkoxycarbonyl)phenylaminomethyl]-2,4'-methylenebis-(phenylcarbamic acid), dialkyl ester, COOR COOR
N - CH2 ~ N - CH2 ~ NHCOOR
and COOR COOR
~ N - CH2 ~ N - CH2 ~

NHCOOR
4 and 3[4-[(alkoxycarbonyl)phenylaminomethyl]phenyl(alkoxy-carbonyl)aminomethyl]phenylcarbamic acid, alkyl ester respectively; and COOR COOR
N - CH2 ~ N - CH2 ~ NHCOOR

CH2.{~1\1HCOOF~
4-[4-[(alkoxycarbonyl(phenylaminomethyl]phenyl(alkoxy-carbonyl)aminomethyl]-2~4'-methylenebis(phenylcarbamic acid), dialkyl ester.

These (alkoxycarbonyl)phenylaminomethylphenyl compounds specifically shown by formula and named are obviously merely representative o~ other N~be~zyl compounds, especially ~he various isomers of such compounds, which ~all ~ithin the de~inition of the general ~ormula herein-above described ~or the compounds which can be converted or rearranged to the desired carbamates especially the polycarbamates by the method o~ this invention. In general, the ethyl esters, i.e., where R is a C2H5 group and which are produced during the condensation of ethylphenylcarbamate (phenylurethane) with a carbonyl compound such as ~ormalde-hyde, are pre~erred ~or the preparation o~ the diethyl esters o~ diphenylmethane dicarbamate and polymethylene polyphenyl carbamates which may be decomposed to the valuable polymeric isocyanates as hereinabove described.
As indicated above, the reaction produc-t includ-ing the N-benzyl compounds which result in unseparable side products during the condensation o~ alkyl esters o~
phenylcarbamic acid such as ethylphenylcarbamate ~ith carbonyl compounds such as ~ormaldehyde in the presence o~
the dilute aqueous acid solution may be processed according to the method o~ the present invention as such or after removal of the ethylphenylcarbamate unreacted starting material. In addition, N-benzyl compo~mds which may be produced by other known methods can be employed in the present process. For example, N-phenylbenzylamine and alkylchloroformate, e.g.~ methyl, ethyl or propylchloro-~ormate may be reacted to prepare the appropriate alkyl N-benzylphenylcarbamate. N-phenyl-~-aminobenzylamine and N-phenyl-4-aminobenzylamine prepared according to the process shown in British Patent Mo. 1~177,557, January, 1970, may be reacted with an excess o~ the alkylchloro~ormate, such 8.

as ethylchloroformate~ to produce 2- and 4-[(ethoxycarbon~Jl)-phenylaminomethyl]phenylcarbamic acid, ethyl ester respective-ly. The 2- and 4-[~alkoxycarbonyl)phenylaminomethyl~phenyl-carbamic acid, alkyl esters may also be prepared by reacting a substituted benzyl alcohol such as for example a carbamic acid, benzyl hydroxy5 ethyl ester (ethylphenylcarbamate-2-methylol) with ethylphenylcarbamate and an acid catalyst.
The protonic acid medium employed as catalysts and suitable for use in the present invention may be either in-organic or organic provided it is a strong acid and has a strength at least equal to a 75 per cent sulfuric acid. The protonic acid catalysts are generally employed in concentra-tions of ~rom 0.1 to 25 ~eight per cent based on the total reaction mixture and preferably from 1 to 10 weight per cent.
Higher concentrations may also be employed. Representative protonic acid catalysts especially suitable for use in this invention are concentrated (75 per cent or higher) sulfuric acid, p-toluene sulfonic acid, trifluoromethane sulfonic acid, anhydrous hydrofluoric acid~ fluorosulfonic acid and strongly acidic sulfonated polyaromatic ion exchange resins (sold, for example, commercially as "Amberlyst 15" by Rohm and Haas Co.) and having a bulk density of approximately 595 g/l., a hydrogen ion concentration o~ approximately 4.9 milliequiva-lents/g. dry, a surface area of from about 40 to 50 m2/g~
and an average pore diameter of from about 200 to 600 Angstrom units. Mixtures of the acid catalysts may be employed but, it is preferable to use individual acid catalyst in order to lessen any recovery problems.
The Lewis acid catalysts which may be employed as catalysts in the present invention may be, for example, tin(I~J)chloride, iron (III)chloride, aluminum chloride5 antimony pentafluoride and boron trifluoride. The Lewis 9.

acid cataFysts which may be supported on, ~or e~ample, graphite, are employed in concentration o~ at least 0~5 preferably in a range of ~rom 0.5 to 20 weight per cent based on the total reaction mixture. The protonic acids are the pre~erred acid catalyst medium. ~ixtures o~ the protonic and Le~is acid catalysts may be employed, L or example BF3 and H2S04, but are not pre~erred.
Although the process of the present invention may be carried out in the absence of solvents, particularly, at the higher temperature o~ reaction, i.e., 100C. and above, solvents or m~xtures o~ solvents ~hich are stable and chemically iner~ to the components o~ the reaction system may be and are generally employed due to the viscosity of the mi~ture o~ N-benzyl compounds in the ~orm o~ dîmers, trimers, tetramers, etc. Suitable solvents ~hich are employ-ed essentially in an anhydrous condition and generally in amounts of ~rom 0 to 50 weight per cent based on the reaction mixture include, ~or example, nitrated and halogenated aromatic hydrocarbons having up to 12 carbon atoms such as nitrobenzenes, nitrotoluenes, dichlorobenzene, dibromobenzene, alkanes and substituted alkanes, havlng up to 16 carbon atoms, such as n-pentanes, isopentane, n-hexane, 2-methyl-pentane, n-heptane, 3,~ dimethylhexane, 2-methylhexane,
3-ethylpentane, cyclopentane, cyclohexane, methylcyclohexane, ethylcyclopentane, cyclooctane, chloro~orm, carbon tetra-chloride, dichloroethane, etc., lo~er aliphatic acids having up to 8 carbon atoms such as acetic, propionic, etc. and lower aliphatic alcohols having up to 8 carbon atoms such as methanol, ethanol, propanols, butanols, etc. Nitrobenzene~
nitrotoluene and dichlorobenzene are the pre~erred solvents.
Greater amounts o~ soIvent, may be employed but generally are not necessarydue to the added burden o~ recovery~ W~ile as 10 .

~ ~$ ~
indicated above, mixtures of solvents may be employed, it is preferable to use indi~idual solvents in order to alleviate any recovery problem As indicated above, the reaction o~ the present invention can be suitably performed by charging the N-ben~yl compounds contained in a condensate or otherwise, together with the protonic or Lewis acid catalyst and solvent into a suitable reactor while main~aining reaction conditions essen-tially anhydrous, and then heating the mixture to the desired temperature. The reaction will proceed at temperatures o~
from about 50C. to 170C. It is generally pre~erred to operate the process at temperatures of ~rom 80C. to 130C.
to obtain a convenient rate o~ reaction. Heating and~or cool ing means may be employed interior and/or exterior of the re-action to maintain the temperature within the desired ranger ~he process o~ the present invention is generally carried out at atmospheric pressure although higher pressures may be used at the higher reaction temperatures~ While they may be used there is no apparent value in employing sub-atmospheric pressures.
The reaction time is generally dependent upon the mixture o~ N-benzyl compounds being reacted, or con-densate being processed, temperature and on the amount and type of acid catalyst being employed and will vary dependent on ~hether the process is continuous or batch but will generally range between about 2 minutes and several hours.
The ~ollowing examples are provided to illustra-te the invention in accordance with the principles o~ this in-vention but are not to be construed as limiting the invention in any way except as indicated by the appended claims.
Although the process of this invention will be directed primarily to the preparation o~ diphenylmethane 11 .

dicarbamate, ethyl esters and the polymethylene polyphenyl carbamates, eth~l esters by the ac~d catalyzed conversion or rearrangement o~ (ethoxycarbonyl)phenylaminomethylphenyl car-bamic acidg ethyl ester, including the higher homolog tr-Lmers~
tetramers, etc~, which are produced for example as side prod-ucts by the condensation o~ ethylphenylcarbamate and a car-bonyl compound as hereinabove described, it is not intended that the process be limited to such (ethoxycarbonyl)phenyl-aminomethylphenyl carbamic acid compounds and those skilled in the art will recognize that the present invention is broadly applicable to the treatment o~ other (alkoxycarbonyl)phenyl-aminomethylphenyl compounds such as the methyl and propyl e`sters and higher homologs~
In the Examples which follow, the reactions were run in 300 ml three neck glass reaction flasks ~itted with a mechanical stirrer, re~lux condenser, and thermometer The reactants were charged to the flask and the ~lask immersed into a constænt temperature oil bath. At the end o~ the reaction time, water was added to the ~lask to quench the reaction and extract the acid medium or the catalyst was removed and recovered by filtration. Conversion o~ the N-benzyl compounds charged and product yield and distribution was determined by high speed liquid chromatography EXAMPLE 1 (Comparative~
2-~(ethoxycarbonyl)phenylaminomethyl]phenylcarbamic acid~ ethyl ester (N-benzyl compound) was prepared by reacting 10 g. o~ N-phenyl-2-aminobenzylamine (prepared by the method described in, ~eilstein Organische Chemie, Volume XIIIg System No. 1740-18713 page 166), with 1.2 g. o~ ethylchloro-formate in the presence o~ 1 m~ pyridine and 50 ml. tetra-hydro~uran as solvent for 1 hr~ at 50C. and then ~iltering to remove pyridine hydrochloride and evaporating the solvent.
12.

0.3 g. of the N-benzyl compound prepared above along with 1.0 g. o~ 37 ~eight per cent h~drochloric acid was heated at 100C. for 60 minutes on a constant tempera-ture bath~ After completion of the reaction, 10 ml. water was added to quench the reaction and extract the hydro-chloric acid medium. Analysis of the resulting reaction product by high speed liquid chromatography showed that 89 per cent of unreacted N-benzyl compounds charged was recovered along with some ethylphenylcarbamate resulting from straight disassociation o~ the N-benzyl compound and other unidentified reaction by products. No rearrangement to diurethane products were detected.
EXAMPLE 2 (Comparative?
The procedure o~ Example 1 was repea-ted employing 0.3 g. of 2-[(ethoxycarbonyl)phenylaminome-thyl]phenyl-carbamic acid, ethyl ester, prepared as shown in Example 1, and 2.0 g. of 49 weight per cent ~ulfuric acid. The mix ture was charged to the reaction ~lask and heated to 100C
~or 60 minutes a~ter which the reaction mixture was quenched with 10 ml water and the acid medium extracted. Chromato-graphic analysis showed that 99 per cent o~ the 2-[(ethoxy-carbonyl)phenylaminomethyl]phenylcarbamic acid, ethyl ester originally charged was recovered unchanged along with an undetermined amount of ethylphenylcarbamate and traces of the diethyl ester of 2~4'-methylenedicarbanilic acid.
~ MPLE 3 (Comparat; ~
0.3 grams of a mixture o~ 2-[(ethoxycarbonyl)-phenylaminomethyl]phenylcarbamic acid5 ethyl ester and
4-[(ethoxycarbonyl)phenylaminomethylJphenylcarbamic acid~
ethyl ester (46 and 54 per cent of the 2 and 4 isomer 13.

respectively) and prepared by reacting a mixture of N-phenyl-2- and 4-aminobenzylamine~ made b~ the method desc~ibed in ~ritish patent 1,177,557~ with ethylchloroformate as ~escribed in Example 1 above, along with 1~0 g of 60 weight per cent sulfuric acid was charged to the reaction ~lask and heated at 110C. for 60 minutes. Analysis showed that essentially all of the 4 isomer was converted to 4,4'-methylene(phenylcarbamic acid)g diethyl ester but that 84 per cent o~ the 2 isomer remained unchanged. The 2 isomer could not be separated from the reaction mixture to allow further processing of the desired diethyl ester urethane, 0.3 g. o~ an ethyl ester o~ 2-[(ethoxycarbonyl)-phenylaminomethyl]phenylcarbamic acid (N-benzyl compound)~
prepared as in Example 1, along with 1.0 g. of 96.4 weight per cent concentrated sulfuric acid was charged to a 300 ml reaction flask. The mixture was heated to 100C.
on a constant temperature bath for 60 minutes~ High speed liquid chromatographic analysis showed conversion of the ethyl ester of 2-[(ethoxycarbonyl)phenylaminomethyl~phenyl-carbamic acid to the diethyl ester o~ 2,4'-methylenebis(phenyl-carbamic)acid and higher homologs to be 99+ per cent with minor amounts o~ ethylphenylcarbamate. A~ter acid extrac-tion with water, the resulting 2,4'-methylenebis(phenyl-carbamic)acid, diethyl ester (diurethane) was subjected to thermal decomposition by the method descr-lbed in U.S. Patent No. 3,962,302 to produce the diphenylme-thane-2 4'-diisocyanate in good yield.

14.

f.~

Example 4 was repeated employing a mixture of 1.0 g~ of the N-benzyl compound of Example 4 along with 3.7 g. of 96.4 weight per cent concentrated sul~uric acid and 4.0 g. of absolute ethyl alcohol as solvent. The mixture was heated to a -temperature of 90C. for 70 minUtes Analysis showed that conversion of the N-benzyl compound to the diurethane was 95 per cent with by-product ethylphenylcarbamate and other unidentified by products present.

A condensation product from the reaction of ethylphenylcarbamate with a 30 per cent aqueous formalde-hyde solution and 37 weight per cent hydrochloric acid in water was prepared according to Example 2 of U.S0 Patent No. 2,946,768 and contained approximately 33 per cent unreacted ethylphenylcarbamate, 38 per cent diphenylmethane dicarbamates (2,4'- and 434'-isomers), 4 per cent -tri~
urethanes, 15 per cent N-benzyl compound dimer (2 and 4 [(ethoxycarbonyl)phenylaminomethyl]phenylcarbamic acid, ethyl ester), 8 per cent N~benzyl compound trimers such as 4[(ethoxycarbonyl)phenylaminomethyl]-2,4'-methylenebis-(phenylcarbamic acid)diethyl ester and a small amount of other unidentified by-products. 6.o g. of the condensation reaction product along with 6.C g. of nitrobenzene solvent and 2.0 g. of 96.4 weight per cent sulfuric acid was charged to a reaction flask and heated at 80C. for 30 minutes. After completion of the reaction and acid extrac-tion~ analysis of the product showed 100 per cent conversion of the N-benzyl compound dimers and trimers to the desired methylene group bridged aromatic di~ and triurethane com-pounds.
15.

~XAMPLE 7 (comparative) Example 6 was repeated employing 6.o gl o~ the same condensation reaction product along with 6,o g.
nitrobenzene solvent and 6. 0 g~ of 37 weight per cent hydrochloric acid. The reaction was carried out at 120C.
for a period o~ 4 hours. Analysis of the product showed that only 2 per cent o~ the contained N-benzyl compounds were rearranged to di or triurethane products.

EYample 6 was repeated employing 6.o g. of the same condensation reaction product along with 6.o g.
o~ nitrobenzene solvent and 6.o gJ of 47 weight per cent sulfuric acid~ The reaction was carried out at 90C~
for 2 hours. Analysis of the reaction product indicated that only 3 per cent of the N-benzyl compounds were rearranged to di or triurethane products.
EXAM
Example 6 was repeated employing 1.0 g. of the condensation reaction product from which essentially all of the unreacted ethylphenylcarbamate was removed by vacuum distillation~ along with 4.0 g. of n-butanol and 3.7 g.
of 96.4 weight per cent sulfuric acid. The mixture was heated at 110C. ~or 1 hour. Analysis of the rearrangement reaction product showed 100 per cent conversion of the contained N-benzyl compound dimers and trimers to the desired urethanes.

A number of runs were carried out according to the procedures of Example 6 but employing 6 g. o~ a con~
densation reaction product of ethylphenylcarbamate with a 30 per cent aqueous ~ormaldehyde solution, 85 per cent commercial grade phosphoric acid and water prepared by 16.
5~

the process o~ UJSC Patent NoO 2,946,768. The condensate contained approximately 28.8 per cent unreacted ethylphenyl-carbamate, 42.4 per cent diphenylmethane dicarbamates (2,4' and 4,4' isomers) 5 per cent tri and higher polymeric urethanes, 16 per cent N-benzyl compound dimers, 6 per cent N-benzyl compound trimers and higher homologs~ Various reaction conditions, solvents and acid catalyst were employed. The reaction product was analyzed by high speed liquid chromatography ~or the N-benzyl compound rearrange-ment. The results are set ~orth in the Table 1 below showing certain values in weight per cent.

17.

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19 .

A run was carried out using 6 g. of a condensation reaction product o~ ethylphenylcarbamate with trioxane (98 per cent) and 60 per cent aqueous sul~uric acid. The con-densate contained approximately 20 per cent unreacted ethylphenylcarbamate, 44 per cent diphenylmethane dicar-bamates (2,4' and 4,4' isomers), 10 per cent tri~ and higher polymeric urethanes, 12 per cent N-benzyl compound dimers and 13 per cent N-benzyl trimers and higher homologs and a small amount of unidentified by-products. The con-densation product was dissolved in 6co g. of nitrobenzene and contacted with 0.70 g. o~ anhydrous iron(III)chloride for 30 minutes at 100C. The reactîon was quenched with water and the iron catalyst was extracted from the organic product by water washing. Rearrangement of N-benzyl com-pounds was 100 per cent as determined by hîgh speed liquid chromatography of the product.

A number of runs were made according to the procedure of Example 11 using 6.o g. nitrobenzene solvent in each run. Various reaction conditions and Lewis acid catalysts were employed. The catalyst was recovered ~rom the product mixture by ~iltration or extracted by water washing and the reaction product analyzed by high speed liquid chromatography for N~benzyl compound rearrangement~
The results are set ~orth in Table 2 20.

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21 .

Claims (19)

The embodiments of the invention in which an exclu-sive property or privilege is claimed are defined as follows:
1. A process for the preparation of a diphenyl-methane mono and dicarbamate and polymethylene polyphenyl carbamate homologs and derivatives which comprises reacting under substantially anhydrous conditions, an (alkoxycarbonyl)-phenylaminomethylphenyl compound having the formula and the higher homologs of said compounds, wherein x, y and z, whlch are different on the ring are an alkyl group of from 1 to 3 carbon atoms, an -NHCOOR, -CH2ArNHCOOR or -N(COOR)CH2Ar group, R is a 1 to 3 carbon alkyl group and Ar is phenyl which may be substituted with an alkyl group of from 1 to 3 carbon atoms; x, y and z may also be at least one hydrogen, at a temperature in the range of from about 50°C. to 170°C, in the presence of an effective amount of a protonic acid catalyst having a strength of at least the magnitude of a 75 per cent sulfuric acid, or a Lewis acid having a concentration of at least 0.5 weight per cent based on the total reaction mixture, to convert the (alkoxy-carbonyl)phenylaminomethylphenyl compounds to the mono and dicarbamates and polymethylene polyphenylcarbamates and derivatives and recovering the desired carbamates.
2. A process according to Claim 1 wherein the (alkoxycarbonyl)phenylaminomethylphenyl compound is derived from the condensation reaction of an N-arylcarbamic acid ester with a carbonyl compound in the presence of a dilute aqueous acid solution.
22.
3. A process according to Claim 2 wherein the N-arylcarbamic acid ester is ethylphenylcarbamate.
4. A process according to Claim 2 wherein the carbonyl compound is formaldehyde.
5. A process according to Claim 1 wherein the (alkoxycarbonyl)phenylaminomethylphenyl compound is the ethyl ester of 2-[(ethoxycarbonyl)phenylaminomethyl]phenyl-carbamic acid or 4-[(ethoxycarbonyl)phenylaminomethyl]phenyl-carbamic acid.
6. A process according to Claim 1 wherein the protonic acid catalyst is an inorganic or organic acid and is employed in concentrations of from 0.1 to 25 weight per cent based on the reaction mixture.
7. A process according to Claim 6 wherein the concentration is from 1 to 10 weight per cent.
8. A process according to Claim 6 wherein the protonic acid catalyst is selected from the group consisting of sulfuric acid, p-toluenesulfonic acid, trifluoromethane sulfonic acid, anhydrous hydrofluoric acid, fluorosulfonic acid and strongly acidic sulfonated polyaromatic ion exchange resins.
9. A process according to Claim 8 wherein the acid catalyst is sulfuric acid.
10. A process according to Claim 1 wherein the reaction is carried out in the presence of a solvent select-ed from the group consisting of nitrated and halogenated hydrocarbons having up to 12 carbon atoms, alkanes and substituted alkanes having up to 16 carbon atoms, lower aliphatic acids and lower aliphatic alcohols having up to 8 carbon atoms.

23.
11. A process according to Claim 10 wherein the solvent is nitrobenzene, nitrotoluene or dichlorobenzene.
12. A process according to Claim 11 wherein the solvent is nitrobenzene.
13. A process according to Claim 1 wherein the reaction is carried out at a temperature in the range of from about 80°C. to 130°C.
14. A process for the preparation of a diphenyl-methane dicarbamate, diethyl ester, which comprises react-ing the ethyl ester of 2-[(ethoxycarbonyl)phenylaminomethyl]-phenylcarbamic acid or 4-[(ethoxycarbonyl)phenylaminomethyl]-phenylcarbamic acid derived from the condensation reaction of ethylphenylcarbamate with a carbonyl compound in the presence of a dilute aqueous acid solution, at atmospheric pressure and at a temperature in the range of from about 80°C. to 130°C. in the presence of sulfuric acid having a strength of between 75 and 100 per cent and recovering the desired diphenylmethane dicarbamates.
15. A process according to Claim 1 wherein the Lewis acid catalyst is selected from the group consisting of tin(IV)chloride, iron(III)chloride, aluminum chloride, antimony pentafluoride and boron trifluoride.
16. A process according to Claim 1 wherein the Lewis acid is employed in concentrations of from 0.5 to 20 weight per cent based on the total reaction mixture.
17. A process according to Claim 1 wherein the Lewis acid catalyst is supported.
18. A process according to Claim 17 wherein the support is graphite.
19. A process for the preparation of a diphenyl-methane dicarbamate, diethyl ester, which comprises react-ing the ethyl ester of 2-[(ethoxycarbonyl)phenylaminomethyl]-24.

phenylcarbamic acid or 4-[(ethoxycarbonyl)phenylaminomethyl]-phenylcarbamic acid derived from the condensation reaction of ethylphenylcarbamate with a carbonyl compound in the presence of a dilute aqueous acid solution, at atmospheric pressure and at a temperature in the range of from about 80°C. to 130°C. in the presence of antimony pentafluoride having a concentration of from 0.5 to 20 weight per cent based on the total reaction mixture, and recovering the desired diphenylmethane dicarbamates.

25.
CA306,259A 1977-10-03 1978-06-27 Process for the preparation of diphenylmethane mono and dicarbamates and polymethylene polyphenyl carbamates by the acid rearrangement of an (alkoxycarbonyl)phenylamino-methylphenyl compound Expired CA1105480A (en)

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US905,705 1978-05-15

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US4202986A (en) * 1979-02-12 1980-05-13 Atlantic Richfield Company Preparation of diphenylmethane dicarbamates and polymethylene polyphenyl carbamates with Lewis acid catalysts intercalated in graphite
US4230877A (en) * 1979-03-22 1980-10-28 Atlantic Richfield Company Method for increasing the 4,4'dicarbamate isomer of the diphenylmethane dicarbamates during preparation thereof
JPS55167273A (en) * 1979-06-18 1980-12-26 Mitsui Toatsu Chem Inc Novel bis(n-carboalkoxy-anilino)methane and its preparation
JPS567749A (en) * 1979-07-03 1981-01-27 Mitsui Toatsu Chem Inc Preparation of polymethylenepolyphenylpolycarbamate
DE2942137A1 (en) * 1979-10-18 1981-04-30 Basf Ag, 6700 Ludwigshafen METHOD FOR PRODUCING METHYLENE-BIS-PHENYLCARBAMINE ACID ESTERS AND POLYMETHYLENE-POLYPHENYLCARBAMIC ACID ESTERS
JPS5679657A (en) * 1979-12-04 1981-06-30 Mitsui Toatsu Chem Inc Novel preparation of polyisocyanate
JPS5721356A (en) * 1980-07-11 1982-02-04 Mitsui Toatsu Chem Inc Production of aromatic polyisocyanate
JPS58194852A (en) * 1982-05-10 1983-11-12 Asahi Chem Ind Co Ltd Production of diphenylmethane dicarbamate
JPS58198454A (en) * 1982-05-12 1983-11-18 Asahi Chem Ind Co Ltd Preparation of diphenylmethane dicarbamate compound
JPS58188860U (en) * 1982-06-11 1983-12-15 日本製罐株式会社 can mouth sealing device
JPS5929651A (en) * 1982-08-11 1984-02-16 Asahi Chem Ind Co Ltd Preparation of polymethylene polyphenyl carbamate
JPS59106453A (en) * 1982-12-09 1984-06-20 Asahi Chem Ind Co Ltd Condensation of n-phenylcarbamate
JPS59104354A (en) * 1982-12-07 1984-06-16 Asahi Chem Ind Co Ltd Preparation of diphenylmethane dicarbamate
JPS59172451A (en) * 1983-03-18 1984-09-29 Asahi Chem Ind Co Ltd Preparation of polyisocyanates
JPS59153962U (en) * 1983-03-31 1984-10-16 三菱重工業株式会社 folding machine
FR2649104B1 (en) * 1989-06-29 1991-09-27 Rhone Poulenc Chimie
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