DD139576A5 - PROCESS FOR PREPARING DIPHENYLMETHANOMONO AND DICARBAMATES AND POLYMETHYLENE POLYPHENYL CARBAMATES - Google Patents

Description

The invention relates to a process for the preparation of esters of aromatic carbamic acids (urethanes), in particular of diphenylmethane-carboxylates and higher homologues and derivatives derived therefrom by the acid-catalyzed rearrangement of (alkoxycarbonyl) -phenylaminomethylphenyl compounds, such as 2 - / (ethoxycarbonyl) -phenylsaminomethyl. phenyl ~ carbamic acid alkyl esters. , -

Characteristic of dex known technical solutions :. Polymeric aromatic carbamic acid esters (polyurethanes), such as diphenylmethanedicarbamates and the higher homologous polymethylene polyphenylcarbamates derived therefrom, have become increasingly important, especially as products for use in the preparation of the commercially important diphenylmethane diisocyanates and mixtures of diisocyanates and diisocyanates Polyisocyanates by decomposition of such polymeric aromatic carbamic in a suitable. Solvent according to ÜS-PS 3,962,302 and 3,919,279.

There is currently no known technically useful process for the direct production of polymeric aromatic esters of carbamic acid. The corresponding commercial diphenylmethane diisocyanates and polyisocyanates are prepared principally by the phosgenation of mixtures of diamines and polyamines obtained by the condensation of aniline and formaldehyde with catalytic amounts of a mineral acid, e.g., U.S. Patent No. 4,014,914.

- a-

A known process for the preparation of polymeric aromatic carbamic acid esters (polyurethanes) makes use of the condensation of arylcarbamic acid esters with carbonyl compounds in a dilute aqueous acid as the condensation medium (US Pat. No. 2,946,768). In this process, however, the carbonyl compound, such as formaldehyde, tends to react on the nitrogen atom of the carbamate to give, in addition to the desired polyurethanes, varying amounts, e.g. generally between 15 and 50 weight percent, of undesired (alkoxycarbonyl) -phenylaminomethylphenyl compounds including the various dimers, trimers and tetramers of such compounds (also referred to hereinafter as "N-benzyl" compounds). Attempts to prepare mono- or diisocyanates and polyisocyanates or otherwise use the mixture containing the undesirable N-benzyl compounds which can not be converted into isocyanates by pyrolysis and polyurethanes, encounter many difficulties due to the lack of a known process for separation of the polyurethanes from the N-benzyl impurities.

The invention relates to a process for the preparation of diphenylmethane mono- and dicarbamates and homologs of higher molecular weight, Polymethylenpolyphenylcarbamaten, wherein a (alkoxycarbonyl) -phenylaminomethylphenylverbindung (N-benzyl compound) is catalytically rearranged with a certain acidic medium. In particular, the invention relates to a process for the preparation of the carbamates by the catalyzed rearrangement of the N-benzyl compounds which, besides urethanes, are by-produced by the condensation of lower alkyl esters of phenolic carbamic acid with carbonyl compounds, such as formaldehyde, in the presence of an aqueous solution. for example, according to US-PS 2,946,768. The product mixture produced in this condensation process, the diurethanes and polyurethanes, N-Benzyl compounds, unreacted Alkylphenylcarbamate and other by-products, for example amines containing, can at temperatures of about 50 to 170 ⁰ C with a protic acid medium with a strength which at least one 75% sulfuric acid, eg concentrated sulfuric acid, is the same,

or an acid medium containing a Lewis acid having a concentration of at least 0.5 percent by weight based on the total reaction mixture, keeping water in the system to a minimum, thereby rendering these N-benzyl compounds the desired Mono-, di- and polyurethanes are catalytically converted or rearranged. However, the unreacted alkylphenylcarbamate can also be removed from the mixture before the treatment, for example by vacuum distillation. The acid rearrangement of N-benzyl compounds resulting from other methods of preparation described below is also effected by the process of the present invention

 Object of the invention:.

One of the objects to be achieved by the invention is therefore to provide a process for the preparation of diphenylmethane mono- and dicarbamates and related polymethylene polyphenylcarbamates in high yields by the conversion or rearrangement of (alkoxycarbonyl) -phenylaminomethylphenyl compounds using a protonic or Lewis acid medium as a catalyst.

Another object of the invention is to provide a process for the acid-catalyzed conversion or rearrangement of (alkoxycarbonyl) -phenylaminomethylphenyl compounds used in the preparation of dimeric and higher polymeric carbamic acid esters by condensation of N-arylcarbamic acid esters such as ethylphenylcarbamate a carbonyl compound in the presence of dilute aqueous acid to the desired di- and polyurethanes are formed.

Explanation of the essence of the invention:

According to the invention, an (alkoxycarbonyl) -phenylaminomethylphenyl compound of the general formula

GOOR

X J 0 VN - CH ₂ - / 0 V χ

)--i ) (

y ζ · ζ y

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which includes the higher homologues of the compounds and wherein x, y and z which are different from each other on the ring, an alkyl group having 1 to 3 carbon atoms, a group of the formula -NHCOOR, -CH ₂ ArNHCOOR or -N (COOR) CH ₂ Ar, or at least one hydrogen atom and R is an alkyl group having 1 to 3 carbon atoms and Ar is an optionally substituted by an alkyl group having 1 to 3 carbon atoms phenyl group, at a temperature of about 50 to 170 ⁰ C, preferably below Atmospheric pressure, with a catalytic amount of a protonic acid medium having the strength of at least that of a 75 percent sulfuric acid or with a Lewis acid medium having a concentration of at least 0.5 percent by weight, based on the total reaction mixture, in the presence or absence of an inert solvent in Contact causing the (alkoxycarbonyl) -phenylaminomethylphenylverbindungen in mono- or dicarb amate and Polymethylenpolyphenylcarbamate and derivatives are catalytically converted or rearranged. For example, the preparation of diethyl diphenylmethanedicarbamate, as shown in the following reaction equation, is carried out using ethyl 2- (ethoxycarbonyl) -phenylaminomethyl / phenylcarbamate:

COOC ₂ H ₅

VI / \ acid _v 0 y ν -CH ₂ Yo))

\ / / \ Solvent NHCOOC ₂ H ₅

2 / (ethoxycarbonyl) -phenylaminomethyiy-phenylcarbaminsaureethylester

- JT-

ICOOCoH

NHCOOC ₂ H ₅

2,4'-methylenebis (phenylcarbamic acid) diethyl ester; (Diphenylmethane-2,4'-dicarbamate, diethyl ester)

The acid-catalyzed rearrangement reaction can be carried out in any reactors which are generally provided with a stirring or shaking device. In general, the procedure is such that the N-benzyl compounds are added together with the protonic or Lewis acid catalyst and optionally a solvent in the reaction vessel and then heated for a certain time to the desired temperature. The reaction may be carried out alone or as a continuous process and the order of addition of the substances may be changed and adapted to the particular apparatus used. The reaction products are obtained by conventional methods and worked up, for. Example by extraction of the acidic medium with water or neutralization with a base, separation of the phases formed and distillation to remove any solvent used or filtering off the Katalysatir.

The (alkoxycarbonyl) -phenylaminomethylphenyl compounds which can be converted or rearranged by the process of the present invention and are characterized by the above general formula are, among others, compounds of the following formulas wherein R is an alkyl group. 1 to 3 carbon atoms:

Alkyl-N-benzylphenylcarbamat

NHCOOR

  COOR i

0 ) - N - CH ₂ - i 0 V NHCOOR

2- and 4 - / (alkoxycarbonyl) -phenylaminomethyl-phenylcarbamic acid alkyl esters,

COOR ι CH ₂ - NHCOOR / - ~ \ IN - a  / 0 V NHCOOR } CH ₂

4 - / (alkoxycarbonyl) -phenylaminomethyl) - 2,4'-methylenebis (phenylcarbamate) dialkyl ester,

/ TV

COOR

N - CH ₂ COOR

N - CH ₂

COOR

N - CHp

- / 0 V

N - CH,

NHCOOR

NHCOOR

4- and 3- / 4-, / (alkoxycarbonyl) -phenylaminomethylZ-phenyl- (alkoxycarbonyl) -aminomethylphenylcarbamate alkyl esters and

COOR ^^^ COOR

ο y. ν - CH ₂ -ZoVn - CH ₂ VoV nhcoor

CH ₂ - / 0 VlIHCOCR

4- / 4 - / _ (alkoxycarbonyl) -phenylaminomethy 1 / -phenyl- (alkoxycarbonyl) aminomethyl ₁ / -2, 4 '-methylenbxs (phenylcarbamic) dialkyl ester!.

The (alkoxycarbonyl) -phenylaminoinethylphenyl compounds listed above by formula and designated are. Of course, these are merely examples of the class of N-benzyl compounds, including in particular the various isomers of the indicated. All compounds of the general formula given can be converted or rearranged by the process according to the invention into the desired carbamates, in particular the polycarbamates. In general, the ethyl esters, i. Compounds in which formula R is a C-H ^ group and which in the

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Condensation of ethyl phenyl carbamate (phenyl urethane) with a carbonyl compound such as formaldehyde is preferred for the preparation of the diethyl esters of diphenylmethanedicarbamic acid and polymethylene polyphenyl carbamates, which can be decomposed to polymeric isocyanates as described above.

As already mentioned, the reaction products, including the N-benzyl compounds used in the condensation of alkyl esters of phenolic carbamic acid, e.g. Ethylphenylcarbamate with carbonyl compounds, such as formaldehyde, in the presence of a dilute aqueous acid, are formed as non-separable products, as such or after removal of unreacted Ethylphenylcarbamatausgangsmaterial be subjected to the inventive method. In addition, N-benzyl compounds produced by other known methods can be introduced into the process of the present invention. Thus, N-phenylbenzylamine and alkyl chloroformates such as methyl, ethyl and propyl chloroformate can be reacted to produce the corresponding alkyl N-benzylphenylcarbamate. N-phenyl-2-aminobenzylamine prepared according to British Patent 1,177,557 and N-phenyl-4-aminobenzylamine can be reacted with an excess of an alkyl chloroformate, e.g. Ethyl chloroformate, to the ethyl ester of 2- or 4 ~ / ^ (ethoxycarbonyl) phenylaminomethyl ^ Z-phenylcarbaminsäure be implemented. The 2- and 4 - / (alkoxycarbonyl) -phenylaminomethylphenylcarbamic acid alkyl esters can also be prepared by reaction of a substituted benzyl alcohol, e.g. a Carbaminsäurebensylhydroxyethylesters (Ethylphenylcarbamat-2-methylol), be prepared with Ethylphenylcarbamat and an acid catalyst.

The protonic acid medium suitable as the catalyst for the process of the present invention may be inorganic or organic, as long as it is a strong acid and has a strength at least equal to that of a 75 percent sulfuric acid. The protonic acid catalyst is generally used in concentrations of 0.1 to

It is also possible to use higher concentrations Examples of protonic acid catalysts which are particularly suitable in the process according to the invention are concentrated (75% or more) sulfuric acid, p-toluenesulfonic acid Trifluoromethanesulfonic acid, anhydrous hydrogen fluoride, fluorosulfonic acid, and strongly acidic sulfonated polyaromatic ion exchange resins (e.g., "Amberlyst 15", Rohm and Haas Co.) having a bulk density of about 595 g / L, a hydrogen ion concentration of about 4.9 milliequivalents / g (dry); a surface of about 40 to 50 m ² / g and an average

Pore diameters of about 200 to 600 A. Mixtures of the acid catalysts can be used, but to facilitate recovery, it is preferred to use individual acid catalysts. '

The Lewis acids which can be used as catalysts in the process according to the invention are, for example, tin (IV) chloride, iron (III) chloride, aluminum chloride, antimony pentafluoride and boron trifluoride. The Lewis acid catalysts, which may be supported on a support such as graphite, are used in concentrations of at least 0.5, preferably in the range of 0.5 to 20 percent by weight based on the total reaction mixture. The protonic acids are the preferred catalyst media. Although mixtures of the protonic and Lewis acid catalysts can be used, for example, BF ₃ and H ₂ SO., But are not preferred.

Although the process according to the invention can be carried out in the absence of solvents, especially at the higher reaction temperatures, ie at 100 ^° C. and above, it is also possible to use solvents or mixtures of solvents which are stable and chemically inert to the constituents of the reaction system and are also generally used because of the viscosity of the mixture of N-benzyl compounds in the form of dimers, trimers, tetramers, etc. Suitable solvents which are

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free state and generally from 0 to 50 weight percent, based on the reaction mixture, are, for example, nitrated and halogenated aromatic hydrocarbons having up to 12 carbon atoms, such as nitrobenzenes, nitrotoluenes, dichlorobenzene, dibromobenzenes, alkanes, and substituted alkanes of up to 16 carbon atoms such as n-pentane, isopentane, η-hexane, 2-methylpentane, n-heptane, 3,4-dimethylhexane, 2-methylhexane, 3-ethylpentane, cyclopentane, cyclohexane, methylcyclohexane, ethylcyclopentane, cyclooctane, chloroform, carbon tetrachloride and dichloroethane lower aliphatic acids having up to 8 carbon atoms, such as acetic acid and propionic acid, and lower aliphatic alcohols having up to 8 carbon atoms, such as methanol, ethanol, propanols and butanols. Nitrobenzene, nitrotoluene and dichlorobenzene are the preferred solvents. Although larger amounts of solvent can be used, they are generally unnecessary and only increase the work-up effort. Although, as already mentioned, solvent mixtures can be used, it is preferred to use individual solvents to facilitate the workup.

As already mentioned, the reaction according to the invention can be carried out simply by introducing the N-benzyl compounds contained in a condensate or other product, together with the protonic or Lewis acid catalyst and solvent into a reactor under substantially anhydrous conditions and heating the mixture on the desired temperature can be performed. The reaction proceeds at temperatures of about 50 to 170 ⁰ C. In general, it is preferred to work at temperatures of 80 to 130 ⁰ C, so as to achieve a convenient reaction rate. In order to maintain the temperature in the desired range, heating or cooling devices arranged in the reaction vessel or outside can be used. , ,

The process according to the invention is generally carried out at atmospheric pressure, but higher pressures can also be used at the higher reaction temperatures. Negative pressures can also be used, but apparently there is no advantage associated with this.

The reaction time generally depends on the mixture of N-benzyl compounds or condensate used, the temperature and the amount and type of acid catalyst used, and also varies depending on whether the process is carried out in individual runs or continuously about £ minutes and several hours.

The invention will be further elucidated in the following examples. Although the process according to the invention is explained primarily in the preparation of ethyl diphenylmethanedicarbamate and polymethylenepolyphenylcarbamate by the acid-catalyzed conversion or rearrangement of (ethoxycarbonyi) -phenylaminomethylphenylcarbaminsäure ethylester including the higher homologs, trimers, tetramers, etc., for example as by-products in the condensation of Ethylphenylcarbamat with a carbonyl compound as mentioned above, but it is not limited to such (ethoxycarbonyi) -phenylaminomethylphenylcarbamic acid compounds, and it will be obvious to those skilled in the art that the invention relates more generally to the treatment of (alkoxycarbonyl) -phenylaminomethylphenylcarbamic acid compounds such as the methyl and propyl esters, and higher homologs.

The reactions illustrated in the following examples are carried out in 300 ml glass three-necked flasks equipped with a mechanical stirrer, reflux condenser and thermometer. The reactants are introduced into the flask, which is placed in an oil bath with constant

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Temperature is immersed. After the end of the reaction time, water is added to the flask to stop the reaction and to extract the acid medium, or the catalyst is recovered by filtration. Conversion of the N-benzyl compound used and product yield and product distribution are determined by high speed liquid chromatography

Examples T

Example 1 (comparative example)

2 - / (ethoxycarbonyl) -phenylaminomethyl / '- phenylcarbarriacetic acid ethyl ester (N-benzyl compound) is prepared by reacting 10 g of N-phenyl-2-aminobenzylamine (prepared according to Beilstein, Organic Chemistry, Vol. XIII, System No. 1740-1871, P. 166) with 1.2 g of ethyl chloroformate in the presence of 1 ml of pyridine and 50 ml of tetrahydrofuran as solvent for 1 hour at 50 ⁰ C ₇ filtered off the pyridine hydrochloride and evaporation of the solvent.

0.3 g of the N-benzyl compound so'hergestellten be heated for 60 minutes by 1.0 g of 37 percent strength by weight hydrochloric acid in a constant temperature bath at 100 ⁰ C. Thereafter, 10 ml of water are added to stop the reaction and to extract the hydrochloric acid medium. Analysis of the resulting reaction product by high speed liquid chromatography yields 89% unreacted N-benzyl compound besides some ethyl phenyl carbamate from the decomposition of the N-benzyl compound and other unidentified reaction byproducts. A rearrangement to diurethane products is not observed.

Example 2 (Comparative Example)

The procedure described in Example 1 is repeated using 0.3 g of ethyl 2-p / (ethoxycarbonyl) -phenylaminomethylphenylcarbamate, prepared as indicated in Example 1, and 2.0 g of 49% by weight of sulfuric acid. The mixture is heated in the reaction flask 60 minutes to 100 ⁰ C, whereupon the reaction was terminated by adding 10 ml of water and the acid medium is extracted. The chromatographic analysis shows that 99% of the originally used 2 - / _ (ethoxycarbonyl) -phenylaminomethyl / -phenylcarbaminsäureethylesters unchanged as an undetermined amount Ethylphenylcarbamat and traces of diethyl ester of 2,4 '-Methylendicarbanilsäure present.

Example 3 (Comparative Example)

0.3 g of a mixture of 2 - / (ethoxycarbonyl) -phenylaminomethy1 / -phenylcarbaminsäureethylester and 4 - / (ethoxycarbonyl) -phenylaminomethy3V ~ phenylcarbaminsäureethylester (4 6 or 54 percent of the 2- and 4-isomers), by reacting a. Mixture of N-phenyl-2- and 4-aminobenzylamine (prepared according to British Patent 1,177,557) and ethyl chloroformate prepared as described in Example 1, together with 1.0 g of 60 weight percent sulfuric acid in the flask, are brought to 110 for 60 minutes ⁰ C heated. Analysis of the product shows that "virtually all of the 4-isomer has been converted to the diethyl ester of 4,4'-methylenebis (phenylcarbamic acid), but that 84% of the 2-isomer remains unchanged. Isomers can not be separated from the reaction mixture, which alone further processing of Diethylesterurethans would be possible.

-IW-

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B e i s ρ i e 1 4

0.3 g of the ethyl ester of 2 - / (ethoxycarbonyl) -phenylaminomethylphenylcarbamic acid (N-benzyl compound) prepared as described in Example 1 is introduced into a 300 ml flask together with 1.0 g of 96.4% by weight concentrated sulfuric acid , The mixture is heated at 100 ^° C. for 60 minutes on a constant temperature bath. The analysis by high-speed liquid chromatography shows a conversion of the ethyl ester of 2 - / (ethoxycarbonyl) -phenylaminomethyl) -phenylcarbamic acid into the diethyl ester of 2,4'-methylenebis (phenylcarbamic acid) and higher homologs of more than 99% in addition to traces of ethylphenylcarbamate , After extraction of the acid with water, the resulting diethyl ester of 2,4'-methylenebis (phenylcarbamic acid) (diurethane) is subjected to thermal decomposition according to US Pat. No. 3,962,302, whereby the diphenylmethane-2,4'-diisocyanate in good yield is obtained.

example

The procedure described in Example 4 is repeated using a mixture of 1.0 g of the N-benzyl compound of Example 4 and 3.7 g of 96.4 weight percent concentrated sulfuric acid and 4.0 grams of absolute ethyl alcohol as the solvent. The mixture is heated to a temperature of 90 ^° C. for 70 minutes. The analysis shows a conversion of the N-benzyl compound to the diurethane of 95% and the formation of ethyl phenyl carbamate and other unidentified by-products.

Example 6 "

According to Example 2 of US Patent 2,946,768 by reaction of Ethylphenylcarbamat with a 30 percent aqueous formaldehyde solution and 37 weight percent hydrochloric acid in

Water, a condensation product was prepared containing about 33% unreacted ethyl phenyl carbamate, 38% diphenylmethane dicarbamate (2,4'- and 4,4'-isomers), 4% triurethanes, 15% dimeric N-benzyl compound (2- and 4 - / - (ethoxycarbonyl ) -phenylaminomethyl / -phenylcarbamic acid ethyl ester), 8% trimeric N-benzyl compounds, · such as 4 - / (ethoxycarbonyl) -phenylaminomethyl / -2,4'-methylenebis (phenylcarbamic acid) -diethyl ester, and containing a small amount of other unidentified by-products , 6.0 g of this condensation product are heated to 80 ^° C. with 6.0 g of nitrobenzene as solvent and 2.0 g of 96.4% by weight sulfuric acid in a flask for 30 minutes. Upon completion of the reaction and extraction of the acid, analysis of the product shows 100 percent conversion of the N-benzyl compound dimers and trimers to the desired methylene-linked aromatic di- and triurethanes.

Example 7 (comparative example)

The procedure described in Example 6 is repeated, using 6.0 g of the same condensation product, 6.0 g of nitrobenzene as solvent and 6.0 g of 37 weight percent hydrochloric acid. The reaction is carried out at 120 ^° C. for 4 hours. Analysis of the product shows that only 2% of the existing N-benzyl compounds have been rearranged into the di- or triurethane products.

Example 8 (Comparative Example)

The procedure described in Example 6 is repeated, using 6.0 g of the same condensation product, 6.0 g of nitrobenzene as solvent and 6.0 g of 47 weight percent

- 46-

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Sulfuric acid can be used. The reaction is carried out at 90 ^° C. for 2 hours. The analysis of the reaction product shows that only 3% of the N-benzyl compounds have been rearranged into di- or triurethane products.

Example 9

The procedure described in Example 6 is repeated, using 1.0 g of the condensation product from which virtually all of the unreacted ethyl phenylcarbamate has been removed by vacuum distillation, 4.0 g of n-butanol and 3.7 g of 96.4 weight percent sulfuric acid , The mixture is heated to 110 ⁰ C for 1 hour. Analysis of the rearrangement product shows a 100 percent conversion of the existing N-benzyl compound dimers and trimers to the desired urethanes.

Example 10

Following the procedure described in Example 6, a series of experiments are carried out using 6 g of a condensation product of ethyl phenylcarbamate with a 30 percent formaldehyde aqueous solution, 85 percent commercial phosphoric acid and water prepared according to U.S. Patent 2,946,668. The condensate contains about 28.8% unreacted ethyl phenyl carbamate, 42.4% diphenylmethane dicarbamate (2,4'- and 4,4'-isomers), 5% tri- and higher polymeric urethanes, 16% dimeric N-benzyl compound, 6% trimer N Benzyl compound and higher homologs thereof. Different reaction conditions, solvents and acid catalysts are used. The reaction product is analyzed by high speed liquid chromatography for N-benzyl compound rearrangement. The results are shown in Table I, where certain values are expressed in weight percent.

T a 'b e' 1 '1' e '' I

Experiment No. Acid catalyst (g) solvent "(Q) Temp. ⁰ C Time min. Conversion of N-benzyl compound in% ⁽¹⁾ 1 96.4% H ₉ SO. (1.85 gr ⁴ (2) absolute ethanol (6.0 G) 100 60 100 2 96.4% H, SO. (2.00 g) ^Z · ⁴ n-butanol (6.0 g) 110 60 100 3 <3) 37% HCl (6.0 g) - 100 240 11.5

anhydrous p-toluenesulfonic acid (3.60 g)

anhydrous p-toluenesulfonic acid (2.00 g)

"Amberlyst 15"

4.9 meq H ./g (2.00 g)

HSO 3 ^F G) (2, 00 h H ₂ SO ₄ 96 4 ί G) (3, 00

Nitrobenzene (6.0 g)

• dichlorobenzene (6.0 g)

Nitrotoluene (6.0 g)

Nitrobenzene (6.0 g)

Nitrobenzene (6.0 g)

120

100

120

100

90

30

30

60

30

100

100

T a b e 1 le "I

Acid catalyst (g) (Continuation) Temp. ⁰ C Time min. Conversion of the N-benzyl compound in% ⁽¹ > Experiment No. 96.4% H ₉ SO ₄ (1.85 gr ⁴ 'Solvent (g) 100 30 100 9 96.4% H ₉ SO- (0.65 g) ^{Z 4} Nitrobenzene (6.0 g) 100 60 76.8 10 96.4% H ₂ SO ₄ Nitrobenzene (6.0 g) 110 60 96.5 11 (1.85 g) n-hexane ⁽²⁾ 75% H ₉ SO. (12.0 g) ⁴ × (6.0 g) 80 30 98 12 Nitrobenzene (6.0 g)

(1) Total conversion of dimers, trimers, tetramers, ect. in the condensate

(2) reaction under a pressure of 3.5 atm (50 psig)

(3) comparative experiment

(4) "Amberlyst-15" (trade mark of Rohm and Haas) - strong acid sulfonated polyaromatic ion exchange resin described above _:

Example 11

An experiment is carried out using 6 g of a condensation product of ethyl phenylcarbamate with trioxane (98%) and 60% aqueous sulfuric acid. The condensate contains about 20% unreacted ethyl phenyl carbamate, 44% diphenylmethane-oxo carbamate (2,4'- and 4,4'-isomer), 10% tri- and higher polymeric urethanes, 12% diniereous N-benzyl compounds and 13% trimeric N-benzyl compounds and higher Homologs and a small amount of unidentified by-products. The condensation product is dissolved in 6.0 g of nitrobenzene and heated to 100 ^° C. with 0.70 g of anhydrous iron (III) chloride for 30 minutes. The reaction is stopped with water and the iron catalyst is extracted from the organic product by washing with water. High-speed liquid chromatography of the product shows a 100 percent rearrangement of the N-benzyl bonds.

Example 12

Following the procedure described in Example 11, a series of experiments are carried out using 6.0 g of nitrobenzene each as solvent. Different reaction conditions and Lewis acid catalysts are used. The catalyst is removed from the product mixture by filtration or by extraction with water, and the reaction product is analyzed by high speed liquid chromatography for N-benzyl compound rearrangement. The results are summarized in Table II.

T e b e Γ 1 β '· II

attempt

No.

Acid-Kätalysä'tor (g)

Iron (III) chloride ¹ ' (0.67 g)

Iron (III) chloride ⁽³⁾ (0.09 g)

Aluminum chloride (1.20 g)

(2)

Antimony pentafluoride

(27% antimony) on graphite as carrier (0.7 g)

(2)

Antimony pentafluoride

(27% antimony) on graphite (0.11 g)

Boron trifluoride etherate (48% boron trifluoride) (2.3 g)

(2)

aluminum chloride

(7% aluminum) on graphite (0.8 g)

Temp. ⁰ C Time 'Min. % N-benzyl- ⁱ⁴⁾ '' conversion 80 30 60 150 15 50 120 60 59 120 60 100

30

60

60

(1) Lewissäure filtered off and washed with water.

(2) Lewis acid filtered off for recovery.

(3) Washed with water for extraction.

(4) Total conversion of dimers, trimers, tetramers, etc. in%

85

94

57

Claims (19)

1. A process for the preparation of diphenylmethane mono- and dicarbamates and Polymethylenpolyphenylcarbamathomologen and derivatives thereof, characterized gekennz e'i c h η e t that under virtually anhydrous conditions (alkoxycarbonyl) -phenylamxnomethylphenylverbindungen the general formula COOR X- / 0 YN - CH ₂ - / 0 Y χ y ζ · Zv wherein x, y and z, which are different on the ring, alkyl groups having 1 to 3 carbon atoms, groups of the formula -NHCOOR, -CH ₂ ArNHCOOR or -N (COOR) CH ₂ Ar ₇ R is an alkyl group having 1 to 3 carbon atoms and Ar is an optionally substituted by an alkyl group having 1 to 3 carbon atoms phenyl group, wherein x, y and ζ may also be at least one hydrogen atom, and higher homologues of these compounds at a temperature of about 50 to 170 ⁰ C in the presence of a protic acid catalyst a strength of at least that of a 75 percent sulfuric acid or a Lewis acid having a concentration of at least 0.5 percent by weight, based on the total reaction mixture, reacted and the formed mono- and dicarbamates and Polymethylenpolyphenylcarbamate or derivatives thereof are obtained. 2. The method according to item 1 _t, characterized in that an (alkoxycarbonyl) -phenylaminomethylphenylverbindung is used, which has been formed from the con-'derisation of an N-Arylcarbarainsäureesters with a carbonyl compound in the presence of a dilute aqueous acid. - 33- 207 3. The method according to item ² / characterized in that has been used as N-Arylcarbaminsäureester Ethylphenylcarbamat. 4. The method according to item 2, characterized in that / has been used as the carbonyl compound formaldehyde. 5. The method of item 1, characterized marked in e ζ j ichnet that as (alkoxycarbonyl) -phenylarainomethylphenylverbindung the ethyl ester of 2 - / (ethoxycarbonyl) -phenylaminomethyl / phenylcarbamic or 4 - / (ethoxycarbonyl) -phenylaminomethy] _ / - phenyl carbamic acid used becomes. 6. The method according to item 1, characterized in that an inorganic or organic acid in concentrations of 0.1 to 25 weight percent, based on the reaction mixture is used as the protic acid catalyst. 7. The method according to item 6, characterized in that a concentration of 1 to 10 Gev / ichtsprozent is applied. 8. The method according to item 6, characterized in that sulfuric acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid, anhydrous hydrogen fluoride, fluorosulfonic acid or a strongly acidic sulfonated polyaromatic ion exchange resin is used as the protonic acid catalyst. 9. The method according to item 8, characterized in that sulfuric acid is used as the acid catalyst is. 10. The method according to »item 1 / characterized in that the reaction in the presence of a nitrated or halogenated hydrocarbon having up to 12 carbon atoms, an optionally substituted alkane having up to 16 carbon atoms, a.niederen aliphatic acid or a lower aliphatic alcohol with up to 8 carbon atoms is carried out as solvent, 11. The method according to item 1 ° / characterized in that nitrobenzene, nitrotoluene or dichlorobenzene is used as a solvent. 12. The method according to item 11, characterized in that nitrobenzene is used. 13. The method according to item 1, characterized in that the reaction is carried out at a temperature of about 80 to 130 ^D C. 14. The method of item -] _r characterized in that formed by condensation of Ethylphenylcarbamat with a carbonyl compound in the presence of a dilute aqueous acid ethyl ester of 2 - / (ethoxycarbonyl) -phenylaminomethyl / -phanylcarbaminsäure or 4 - / _ (ethoxycarbonyl) -phenylaminomethyl / -phenylcarbamic acid at atmospheric pressure and a temperature of 207 95 about 80 to 130 ° C in the presence of sulfuric acid having a strength of 75 to 100% reacted and the Diphenylmethandxcarbamat formed is recovered. 15. The method according to item 1 /, characterized in that is used as the Lewis acid catalyst tin (IV) chloride, iron (III) chloride, aluminum chloride, antimony pentafluoride or boron trifluoride. 16. Procedure according to point ( i), characterized in that the Lewis acid is present in a concentration of 0.5 to. 20 weight percent, based on the total reaction mixture is used. 17. The method according to item 1, characterized in that the Lewis acid catalyst is used as a supported catalyst. 18. The method according to item 17 /, characterized in that graphite is used as the carrier. 19. The method according to item 1, 'characterized in that the obtained by condensation of Ethylphenylcarbamat with a carbonyl compound in the presence of a dilute aqueous acid ethyl ester of 2- / (ethoxycarbonyl) -phenylaminomethyi- phenylcarbamic acid or 4 - / _ (ethoxycarbonyl) -phenylaminomethylV- phenylcarbamic acid at atmospheric pressure and a temperature of about to 130 ⁰ C in the presence of antimony pentafluoride in a concentration of 0.5 to 2O weight percent, based on the total reaction mixture, reacted and the resulting. Diphenylmethandxcarbamat is recovered.