CA1137514A - Process for the preparation of polyamines of the diphenyl methane series which are rich in ortho isomers - Google Patents

Process for the preparation of polyamines of the diphenyl methane series which are rich in ortho isomers

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Publication number
CA1137514A
CA1137514A CA000319238A CA319238A CA1137514A CA 1137514 A CA1137514 A CA 1137514A CA 000319238 A CA000319238 A CA 000319238A CA 319238 A CA319238 A CA 319238A CA 1137514 A CA1137514 A CA 1137514A
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Canada
Prior art keywords
aromatic amine
total quantity
strong acids
temperature
acid
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Expired
Application number
CA000319238A
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French (fr)
Inventor
Willi Eifler
Gunther Ellendt
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Bayer AG
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Bayer AG
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Filing date
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Publication of CA1137514A publication Critical patent/CA1137514A/en
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Classifications

    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C209/00Preparation of compounds containing amino groups bound to a carbon skeleton
    • C07C209/68Preparation of compounds containing amino groups bound to a carbon skeleton from amines, by reactions not involving amino groups, e.g. reduction of unsaturated amines, aromatisation, or substitution of the carbon skeleton
    • C07C209/78Preparation of compounds containing amino groups bound to a carbon skeleton from amines, by reactions not involving amino groups, e.g. reduction of unsaturated amines, aromatisation, or substitution of the carbon skeleton from carbonyl compounds, e.g. from formaldehyde, and amines having amino groups bound to carbon atoms of six-membered aromatic rings, with formation of methylene-diarylamines

Abstract

Mo-1914 LeA 18,671 PROCESS FOR THE PREPARATION OF POLYAMINES
OF THE DIPHENYL METHANE SERIES WHICH
ARE RICH IN ORTHO. ISOMERS

ABSTRACT OF THE DISCLOSURE

The instant invention is directed to a process for the preparation of polyamines of the diphenyl methane series which are rich in ortho isomers, which comprises: (a) reacting an aromatic amine with formaldehyde to produce N-substituted pre-condensates; (b) removing the water formed in this reaction as well as any water introduced in the form of aqueous formaldehyde solution; (c) rearranging said pre-condensates in the presence of aromatic amine salts of strong acids to the corresponding primary amines substituted on the aromatic nucleus; (d) neutralizing said aromatic amine salts of strong acids; and (e) subsequently working up in known manner the resulting reaction products; wherein the quantities of reactants and of said strong acids are calculated so that the total quantity of aromatic amine used corresponds to an aromatic amine/formaldehyde molar ratio of from 4:1 to 20:1, and the total quantity of strong acid added, based on the total quantity of aromatic amine, corresponds to an aromatic amine/acid equivalent ratio of from 10:1 to 1,000:1, and at least half of the total quantity of aromatic amine used is combined with the acid to form an aromatic amine/aromatic amine salt mixture; said aromatic amine/aromatic amine salt mixture is heated to a temperature of from 100 to 200°C, said N-substituted pre-condensate, which has been maintained at a temperature of from 0 to 100°C, is introduced into this mixture; and said rearrangement of the pre-condensate is then completed at a temperature within the range of from 100 to 250°C.

LeA 18,671

Description

Mo- 1 9 1 4 LeA 18,671 PROC~SS FOR THE PREPAR~ION OF POLYAMINES
OF TIIE DIP~ENYL METHANE S~RIES WHICH
AR~ RICH IN ORT~O ISOMERS

~ACKGROUMD OF THE INVF~NTION

This invention relates to an improved process for the preparation of polyamines, of the diphenyl methane series with a high yield of diaminodiphenyl methanes, i.e. di-nuclear diamines with high yields of ortho isomers, in particular, 2,2'- and 2,4'-diaminodiphenyl methane.

The problem of obtaining polyamine mixtures of the diphenyl methane series which contain a high proportion of dinuclear components having a high ortho isomer content has not yet been satisfactorily solved by the known processes of aniline/formaldehyde condensation. Although the process disclosed in German Offenlegungsschrift 1,937,~85, for example, enables polyamines which contain a high proportion of ortho isomers to be obtained, the proportion of diamines contained in the polyamine mixtures given in the examples of the reference are below 80% in all cases. Also in the process of the reference, the aminal formed from aniline and formal-dehyde must be heated to at least 125C, which pre-supposes careful removal of the last traces of molsture.

The process of the present invention provides a means of preparing polyamine mixtures of the diphenyl methane series having an exceptionally high proportion of diamines and at the same time arl exceptionally high proportion of ortho isomers, without the above-mentioned disadvantages of the processes known in the art. The process of the present invention also makes it possible to prepare polyamines with T, 'A 18, 671 ~13'~514 a high diamines content in which the proportions of isomers can be adjusted within wide limits.

DESCRIPTION OE` THE INVENTION

Tll~ present invention relates to a process for the preparation of polyamines of the diphenyl methane series which are rich in ortho lsomers, comprising: reacting an aromatic amine, preferably aniline, with formaldehyde to produce N-substituted pre-condensates; removing the water formed in the reaction and any water introduced in the form of aqueous formaldehyde solution; rearranging the pre-con-densates to the corresponding primary amines substituted on the aromatic nucleus in the presence of aromatic amine salts, preferably aniline salts of strong acids; neutralizing the catalyst used; and working up the resulting reaction products by known methods. The reactants and the aforesaid strong acids are used in such quantities that the total quantity of aromatic amine used corresponds to an aromatic amine~
formaldehyde molar ratio of from 4:1 to 20:1. Also, the total quantity of strong acids used, based on the total quantity of aromatic amine used, corresponds to an aromatic amine/acid equivalent ratio of from 10:1 to 1,000:1. The process is characterized in that at least half the total quantity of aromatic amine used is combined with the acid to form an aromatlc amine/aromatic amine salt mixture; the mixture is heated to a temperature of from 100 to 200C; the N-substituted pre-condensate, which is maintained at a temperature of from 0 to 100C, is introduced into this mixture; and rearrangement of the pre-condensate is then completed at a temperature in the range of from 100 to 250C.

LeA 18,671 1~3~51~

The startinc3 materials used for the process according to the present invention are aromatic amines and formaldehyde.

Aniline is the preferred aromatic amine. Examples of other possible aromatic amines include o- and m-toluidine, o- and m-anisidine, o- and m-phenetidine, N-methylaniline, _ N-ethylaniline, 2,4-diaminotolue~e or any mixtures of such amlnes, The formaldehyde is preferably used in the form of aqueous formaldehyde solution although any substance which releases formaldehyde under the reaction conditions could, of course, be used.

The catalysts which are preferably used in the present invention are water-soluble acids having a pKa-value below 2.5, preferably below 1.5. The following are examples:
hydrochloric acid, hydrobromic acid, sulfuric acid, tri-fluoroacetic acid, methane sulfonic acid, trifluoromethane sulfonic acid, benzene sulfonic acid and phosphoric acid.

The preferred catalyst is hydrochloric acid. The acids mentioned above may be used as mixtures with acidic or neutral salts of such acids, e.g. with the corresponding ammonium salts or the corresponding alkali metal salts;
however, this is less advantageous.

Thebases used for neutralizing the acids are preferably aqueous inorganic bases, such as sodium h~droxide.

To carry out the process of the present invention, a N-substituted pre-condensate, i.e. an aminal, is first prepared from an aromatic amine and formaldehyde in the LeA 18,671 ~137Sl~

absence of the above-mentioned catalysts. This reaction is carried out by known methods at a temperature in the range of from 0 to 100C, preferably from 30 to 80C. The water of condensation formed in the reaction, as well as any water introduced in the form of aqueous formaldehyde solution (formalin), is removed by phase separation after aminal formation. If required, this may be followed by a procedure such as vacuum distillation to remove the last traces of moisture, although such a complete removal of water is generally not necessary after phase separation.

The reactants for this pre-condensation are used in quantities corresponding to an aromatic amine/formaldehyde molar ratio of at least 2:1. The ratio of the total quantity of aromatic amine used in the process according to the present invention, including the quantity used in the second stage together with the acid catalyst, to the quantity of formaldehyde corresponds to a molar ratio of aromatic amine to formaldehyde of from 4:1 to 20:1, preferably from 8:1 to 20:1, and at the most half of the total quantity of aromatic amine is used in the first stage, which leads to the formation of aminal. ~his means that at least half the total quantity of aromatic amine is used in the second reaction step.

The aminal obtained in the first stage of the reaction, or its solution in any excess aromatic am ne present, is at a temperature of from 0 to 100C, preferably 30 to 80C before the second stage of the reaction, i.e.

before it is combined with the aromatic amine salt catalysts.

In the next stage of the process according to the present invention, the aminal or its solution in excess aromatic amine is combined with an aromatic amine acid LeA 18,671 ~37S14 mixture whic~- has bee~ ob-tained by partial neutralization of a second quantity of aromatic amine with one of the acid catalysts exemplified above.

For this partial neutrali2ation, the acid may be used in quantities corresponding to a deyree of protonation of from 0.1 to 10~, preferably from 0.1 to 5%, based o~ all the amino nitrogen atoms present in the reaction mixture.
These figures should include all the amino nitrogen atoms present, including those of the aromatic amine used in excess for aminal formation, and those of the aromatic amine used together with the acid. 13y "degree of protonation" is meant the percentage of amino nitrogen atoms present in the form of ammonium groups, i.e. of "protonated" amino nitrogen atoms, based on the total quantity of amino nitrogen atoms.

When the partially neutralized aromatic amine is combined with the aminal component, the former is maintained at a temperature in the range of from 100 to 200C, preferably from 100 to 150C.

When the two compounds have been combined, the aminal is rearranged to the polyamine substituted in the nucleus by heating of the reaction mixture to from 100 to 250C, preferably from 120 to 200C, for a period of from ca. S to 300 minutes.

The choice of temperature employed for the rearrangement reaction depends mainly on the molar ratio of aromatic amine/catalyst employed and on the adjusted dwell time for the rearrangement. If the molar ratio is low and the dwell time is long, the rearrangement temperature may LeA 18,671 ~137514 be maintained at the lower limit of the given range of from 100 to 250C, whereas under converse conditions, high rearrangement temperatures are to be recornmended, especially if the aromatic amine/catalyst molar ratio is high. The temper-S ature employed in the process according to the presentinvention is generally from 120 to 200C at atmospheric or excess pressure.

The process according to the present invention may, of course, be carried out either continuously or intermittently, and known apparatus may be used in both cases. The continuous process may, for example, be carried out as follows:

Measured and regulated streams of aromatic amine and aqueous formaldehyde solution (formalin) are converted into the ~-substituted aminal in a continuously operated reactor within the above-mentioned temperature range. The heat liberated in the reaction may either be left in the reaction mixture or removed by a heat exchange process.
The resulting two phase reaction mixture is separated in a continuously operated phase separator. The upper, aqueous phase is transferred to an apparatus for working up the effluent. The lower, organic phase is combined with a measured and regulated stream of an aromatic amine/hydro-chloric acid mixture in another continuously operated reactor, said aromatic amine/hydrochloric acid rnixture conforming to the particulars given above in its cornposition and temperature. The rearrangement reaction is subsequently carried out in several reactors arranged in series maintained at a temperature within the range mentioned above for the rearrangement reaction. Any water or azeotropic mixture of water/aromatic amine evaporating at a temperature above 100(' LeA 18,671 ~13751~

is transferred to the reactor for aminal formation or to the separator following this reactor. The usual working up of the reaction mixture then takes place. This consists mainly of neutralization of the catalyst and isolation of the products of the process by distillation.

The products obtained by the process according to the present invention may be reacted with phosgene to produce isocyanates by known methods. The products obtained by the present process are also suitable for use as cross-linking agents for epoxides or for modified i~socyanates.

The following examples illustrate the present invention. Both the hydrochloric acid and the formalin are used as 30% aqueous solutions.

EXAMPLES

EXAMPLE 1 (comparison) 558 g (6 mol) of aniline and 200 g (2 mol) of formalin are mixed together with stirring at room temperature.
The temperature rises to 65C. Stirring is continued for 30 minutes at 65C, and the phases are separated at 65C.

The organic phase is introduced into a mixture of 1302 g (14 mol) of aniline and 40.6 g (0.33 mol) of hydrochloric acid which has been pre-heated to 40C. The mixture is heated to boiling and kept under reflux at 128C for 4 hours.
It is then neutralized with 350 ml of 6% sodium hydroxide solution. The separated organic phase is heated in a water jet vacuum to a head temperature of 220C. The distillation residue constitutes the product of the process. It contains LeA 18,671 113~5~4 89.1~ of diamines. The distribution of isomers determined using gas chromatography is shown in the table.

EX~MPLE 2 (comparison) The procedure is the same as in Example 1, except that the aniline/hydrochloric acid mixture is not pre-heated to 40C but to 80C. The analysis is shown in the table.

The procedure is the same as in Example 1, except that the aniline/hydroc~loric acid mixture is not pre-heated to 40C but to 120C. The analysis is shown in the table.

The procedure is analogous to that described in Example 1. The analyses are shown in the table. As is evidenced by Examples 7 and 8, pre-heating the aniline/
hydrochloric acid mixture in accordance with the instant invention to at least 100C increases the yield of ortho isomers.

The procedure is analogous to that described in Example 1, and is carried out in accordance with the particulars given in the table, except that the reflux temperature of the acid reaction mixture is raised to 180C
by distilling off water. After 60 minutes at 180C, the subse~uent procedure is the same as that described in Example 1. The analyses are shown in the table.

LeA 18,671 113751~

__ The procedure is similar to that described in Example 10, but the boiling point of the acid reaction mixture is raised to 185C by removal of water by distilla-tion. This temperature is then maintained for 90 minutesand 180 minutes, respectively. The analyses are shown in the table.

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~ ~ '.D\DV~ LD ~D ~ CO ~D V~ r~ rn ~
~ U ~ o o o o o o o o o ,; r- ~

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tJ; ~ ~ ~ CO o r~ ~ Ln Ln ~ Ln Ln ~,~ o o oco ~ ~ r~ LnLn co ~:: ~ r~ ~ ~ ~r~
~; r~ r~r~ r~ ~ ~~ r~

-~ O O O O OO O O O O O O
t3 b' o o o oo o o o o o o o ~ ~ ~ ~ J

co ~o ~ o r~ oo Ln Ln ~7 Ln In ~1 r:J ~ ,n ,n r~ ~ Ln ~D ~D ~r ~ ~D
.~ Ln Ln Ln ~ cn ~r Ln er ~r ~ d' ~r r~ ~
1~1 ,~ ~ Ln ~D r~ o ,-1 ~

LeA 18,671

Claims (10)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:-
1. A process for the preparation of polyamines of the diphenyl methane series which are rich in ortho isomers, which comprises: (a) reacting an aromatic amine with formal-dehyde to produce N-substituted pre-condensates; (b) removing the water formed in this reaction as well as any water intro-duced in the form of aqueous formaldehyde solution; (c) re-arranging said pre-condensates in the presence of aromatic amine salts of strong acids to the corresponding primary amines substituted on the aromatic nucleus; (d) neutralizing said aromatic amine salts of strong acids; and (e) subsequently working up in known manner the resulting reaction products;
wherein the quantities of reactants and of said strong acids are calculated so that the total quantity of aromatic amine used corresponds to an aromatic amine formaldehyde molar ratio of from 4:1 to 20:1, and the total quantity of strong acid added, based on the total quantity of aromatic amine, corresponds to an aromatic amine acid equivalent ratio of from 10:1 to 1,000:1, and at least half the total quantity of aromatic amine used is combined with the acid to form an aromatic amine/aromatic amine salt mixture; said aromatic amine aromatic amine salt mixture is heated to a temperature of from 100 to 200°C, said N-substituted pre-condensate, which has been maintained at a temperature of from 0 to 100°C, is introduced into this mixture; and said rearrangement of the pre-condensate is then completed at a temperature within the range of from 100 to 250°C.
2. A process for the preparation of polyamines of the diphenyl methane series which are rich in ortho isomers, comprising:

LeA 18,671 (a) reacting an aromatic amine with formaldehyde at 0 to 100°C to form N-substituted pre-condensates;
(b) removing the water formed in the reaction and any water introduced in the form of aqueous formaldehyde solution:
(c) rearranging at 100 to 250°C said pre-condensates to the corresponding primary amines substituted on the aromatic nucleus by reacting in the presence of a mixture of (i) aromatic amine which is at least half the total quantity of aromatic amine used in the process, and (ii) aromatic amine salts of strong acids, said mixture having been heated to a temperature of from 100 to 200°C;
(d) neutralizing said aromatic amine salts of strong acids; and (e) working up in known manner the resulting products;
wherein the quantities of reactants and of said strong acids are calculated so that the total quantity of aromatic amine used corresponds to an aromatic amine/formaldehyde molar ratio of from 4:1 to 20:1, and the total quantity of strong acid added, based on the total quantity of aromatic amine, corresponds to an aromatic amine/acid equivalent ratio of from 10:1 to 1,000:1.
3. The process of Claim 2 wherein said strong acids are water soluble and have a pKa-value below 2.5.

LeA 18,671
4. The process of Claim 2 wherein said aromatic amine is aniline and said aromatic amine salts of strong acids are aniline salts of strong acids.
5. The process of Claim 3 wherein said strong acid is hydrochloric acid.
6. The process of Claim 2 wherein the quantities of reactants and of said strong acids are calculated so that the total quantity of aromatic amine used corresponds to an aromatic amine/formaldehyde molar ratio of 8:1 to 20:1.
7. The process of Claim 2 wherein said reaction of aromatic amine with formaldehyde is carried out at 30 to 80°C.
8. The process of Claim 2 wherein said aromatic amine/aromatic amine salt of a strong acid mixture is introduced at a temperature of 100 to 150°C.
9. The process of Claim 2 wherein said rearrangement reaction is conducted at 120 to 200°C for a period of 5 to 300 minutes.
10. The process of Claim 2 wherein said neutralizing step is accomplished with the use of sodium hydroxide.

?eA 18,671
CA000319238A 1978-01-25 1979-01-08 Process for the preparation of polyamines of the diphenyl methane series which are rich in ortho isomers Expired CA1137514A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE2803126 1978-01-25
DEP2803126.7 1978-01-25

Publications (1)

Publication Number Publication Date
CA1137514A true CA1137514A (en) 1982-12-14

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CA000319238A Expired CA1137514A (en) 1978-01-25 1979-01-08 Process for the preparation of polyamines of the diphenyl methane series which are rich in ortho isomers

Country Status (6)

Country Link
EP (1) EP0003303B1 (en)
JP (1) JPS54117429A (en)
BR (1) BR7900430A (en)
CA (1) CA1137514A (en)
DE (1) DE2960014D1 (en)
ES (1) ES477114A1 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7038002B2 (en) 2003-07-25 2006-05-02 Bayer Materialscience Ag Production of mixtures of diisocyanates and polyisocyanates from the diphenylmethane series with high contents of 4,4′-methylenediphenyl diisocyanate and 2,4′-methylenediphenyl diisocyanate
US7495124B2 (en) 2004-02-04 2009-02-24 Bayer Materialscience Ag Process for the production of very pure 2,4′-methylenediphenyl diisocyanate
US8557949B2 (en) 2007-09-19 2013-10-15 Huntsman International Llc Process for production of di- and polyamines of the diphenylmethane series
US9217054B2 (en) 2007-09-19 2015-12-22 Huntsman International Llc Process for production of di- and polyamines of the diphenylmethane series

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4259526A (en) * 1979-02-21 1981-03-31 Bayer Aktiengesellschaft Process for the preparation of mixtures of polyamines of the polyamino-polyaryl-polymethylene type
DE2947531A1 (en) * 1979-11-26 1981-06-04 Basf Ag, 6700 Ludwigshafen METHOD FOR PRODUCING POLYPHENYLPOLYMETHYLENEPOLYAMINES
DE3407494A1 (en) * 1984-03-01 1985-09-05 Bayer Ag, 5090 Leverkusen METHOD FOR PRODUCING POLYAMINES AND THE USE THEREOF FOR PRODUCING POLYISOCYANATES
DE10111337A1 (en) * 2001-03-08 2002-09-12 Basf Ag Process for the production of MDI, in particular 2.4'-MDI
WO2007065767A1 (en) 2005-12-08 2007-06-14 Huntsman International Llc Process for preparing diaminodiphenylmethanes

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3297759A (en) * 1964-01-13 1967-01-10 Upjohn Co Continuous process for producing mixtures of methylene-bridged polyphenyl polyamines
US3676497A (en) * 1968-08-06 1972-07-11 Upjohn Co Process for preparing di(aminophenyl)-methanes
JPS5038095B2 (en) * 1971-08-26 1975-12-06
JPS5028081B2 (en) * 1971-09-01 1975-09-12
DE2426116B2 (en) * 1973-06-01 1978-05-11 Efim Freiburg Biller (Schweiz) Process for the preparation of polyarylamines having methylene bridges
JPS5141633A (en) * 1974-10-07 1976-04-08 Fuji Industries Co Ltd KINZOKUSOSEIKAKOKINIOKERU RIKEIZAITOFUSOCHI

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7038002B2 (en) 2003-07-25 2006-05-02 Bayer Materialscience Ag Production of mixtures of diisocyanates and polyisocyanates from the diphenylmethane series with high contents of 4,4′-methylenediphenyl diisocyanate and 2,4′-methylenediphenyl diisocyanate
US7495124B2 (en) 2004-02-04 2009-02-24 Bayer Materialscience Ag Process for the production of very pure 2,4′-methylenediphenyl diisocyanate
US8557949B2 (en) 2007-09-19 2013-10-15 Huntsman International Llc Process for production of di- and polyamines of the diphenylmethane series
US9217054B2 (en) 2007-09-19 2015-12-22 Huntsman International Llc Process for production of di- and polyamines of the diphenylmethane series

Also Published As

Publication number Publication date
BR7900430A (en) 1979-08-21
JPS6331454B2 (en) 1988-06-23
ES477114A1 (en) 1979-07-01
JPS54117429A (en) 1979-09-12
DE2960014D1 (en) 1980-12-18
EP0003303B1 (en) 1980-09-17
EP0003303A1 (en) 1979-08-08

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