DE3007940A1 - Di:amino:di:phenyl:methane prepn. from aniline and formaldehyde - by condensing in presence of hydroxy:ethane sulphonic acid catalyst recovered by water extraction - Google Patents

Abstract

Prepn. of diaminodiphenylmethane and higher homologues comprises condensing aniline and HCHO in the presence of a hydroxyethane sulphonic acid catalyst pref. in amt. of 10-70, esp. 20-40 mole % (based on moles of aniline) and recovering the catalyst by extraction of the salt with water. The products may be used in forming the corresponding polyisocyanates or as epoxy curing agents. The catalysts salts are much more soluble than the corresponding aniline salt of methane sulphonic acid, resulting in reduced salids build-up.

Description

METHOD FOR MANUFACTURING

DIAMINODIPHENYL METHANE AND ITS HIGHER HOMOLOGOUS procedure for the preparation of diaminodiphenylmethane and its higher homologues The present Invention relates to polyamines.

There are many known methods of making aromatic Aniline and formaldehyde polyamines are some of them in U.S. Patents 2,683 730, 3,277,173, 3,344,162 and 3,362,979. By implementing these amines the corresponding isocyanates are obtained with phosgene. The by condensation Polyamines made from aniline and formaldehyde usually consist of one Mixture of polymethylene phenylamines with a functionality of more than 2 and the 2.2t, 2.4t and 4,4-isomers of diaminodiphenylmethane.

The reaction with phosgene produces a corresponding mixture Polyisocyanates and diisocyanates produced e.g.

for the production of polyurethane foam or as a hardening agent is suitable for epoxies.

A variant of the reaction of aniline with formaldehyde includes adding a strong mineral acid, such as hydrochloric acid, to the reaction mixture. Here a reaction takes place between the corresponding aniline hydrochloride and the Formaldehyde instead, a reaction mixture is formed from which after neutralization the polyphenylamines can be obtained with a base. This procedure possesses still many disadvantages. For example, it is necessary to use large amounts of mineral acid and base use, which in turn worsen the economy of the process and also the Make the reaction difficult to carry out. In addition, great use occurs Amounts of mineral acids and bases pose a significant corrosion problem. The educated Inorganic salt also represents in the destruction and / or Recovery poses an environmental problem.

As an improvement on the conventional mineral acid-catalyzed aniline-formaldehyde condensation disclosed the use of a solid acidic silicon catalyst in U.S. Patent 3,362,979 described. This has economic advantages over conventional hydrochloric acid catalyzed processes because of the use of large amounts of corrosive acids and bases is avoided. But this method also has some disadvantages on the one hand the implementation does not proceed as quickly as desired and, on the other hand, there is the rearrangement of the amine products are still not considered sufficient under conventional conditions.

Methanesulfonic acid is also used as the acid catalyst for the above-mentioned reaction used. However, like hydrochloric acid, this acid forms at the beginning of the reaction insoluble aniline salts, causing solids buildup and agitator problems leads.

There are also excesses of hydrochloric acid and methanesulfonic acid difficult to remove by aqueous extraction after the reaction. Step last there are also problems with the recovery of the catalyst, since it is carried out at room temperature normally solid amine salts of methanesulfonic acid in the enrichment of the catalyst To cause difficulties.

The present invention relates to a method for producing aromatic polyamines by reacting aniline with formaldehyde in the presence a hydroxyethanesulfonic acid catalyst.

A process for making diaminodiphenylmethane and developed its higher homologue. The present invention includes condensation of aniline and formaldehyde in the presence of a hydroxyethanesulfonic acid catalyst.

This creates a mixture of products, the diaminodiphenylmethane isomer contains, such as 2,2'-, 2,4'- and 4,4'-Giamirto isomer and their higher homologues or Polyethylene polyphenylamine. The latter are condensation polymers made from formaldehyde and higher molecular weight aniline and are considered homologues of the simple diaminodiphenylmethane isomers.

Depending on the reaction conditions, the amount used of the catalyst, the amounts of the reactants and other variables can affect the im Amounts of diamines and higher polyamines present in the product mixture varied widely will. However, the reaction mixture usually contains 20-80% by weight of diamines, the The rest are higher polyamines. The proportion of diamines in the reaction mixture is, however often at 30-70% and mostly at about 35-55 wt., Accordingly, in the preferred Embodiment the higher polymeric products usually at 30-70% by weight and most of the time represented by about 45-65 total%.

1-lo wt. Of the entire mixture of dimers is obtained as a 2,2'-isomer, the remainder are the 2,4t and 4,4'-isomers, mostly the mixture of dimers consists of 1-5 ffi from the 2,2'-isomer and 95-99% from the 2,4t- and 4,4t-isomers. The polymethylene polyphenyl polyamines higher molecular weight usually have an average. Functionality from about 2.2 to about 4.5, mostly from 2.2-3, o The hydroxyethanesulfonic acid is well known and needs no further explanation.

The amount of catalyst used remains the choice of the experimenter left. Usually, however, 10-70 mol% of catalyst based on the amount used Moles of aniline applied.

In most cases, however, 20-40 mol% of catalyst are used, based on the amount of catalyst used Aniline applied.

For the production of the methylene-bridged polyphenyl polyamines (the Term includes diaminodiphenylmethane isomers and their higher homologues or higher polymers a) the following process conditions are preferred.

The molar ratio of aniline to foramaldehyde can be about a proportionate can be varied over a wide range. For example, about 1 to about 10 moles of aniline per Moles of formaldehyde are used. In general; with low aniline: formaldehyde ratios, e.g., between about 1: 1 and about 2.5: 1, the formation of the higher polymers is preferred; their yield is higher than that of dimers. However, the yield of dimers increases with the use of larger amounts of aniline at the expense of the polymer yield. So there is the reaction product at an aniline: formaldehyde ratio of about 3: 1 to about 10: 1 or more mainly from the dimer. As mentioned above, this is dimer a mixture of the 2,2? -, 2,4'- and 4,4t-diamino isomers.

Formaldehyde can be in any of the commercially available forms, e.g. used as formalin, paraformaldehyde, "stabilized" solution in methanol, etc. will.

The reaction can be carried out in the presence or absence of a solvent be performed. When a solvent is used, any of the conventional ones can be used Hydrocarbon solvents or chlorinated solvents, e.g.

aromatic or aliphatic solvents with a boiling point of about 100 to about 2000C can be used. The solvent should be in an amount are used, which is sufficient to produce a single-phase solution of the amine compound.

The reaction temperature should range from about 75 to about 150 C, preferably from about 90 to about 105 ° C.

The pressure is not critical to the procedure, it should however, be sufficient to meet the conditions of a liquid phase reaction. This means that pressures from 1 to 70 bar can be used.

The reaction proceeds well under the above conditions and is usually after one to three following the completion of formalin addition heating to 90-105 ° C for hours essentially completely. The formaldehyde will however, because of the exothermic nature of the reaction, it is preferably added at a rate at which a temperature of 20-70 C is maintained. The reaction mixture should at the end of the formalin addition preferably have a temperature of about 65-7o0C. The reaction mixture is then heated to 90-105 C and with stirring for 1-3 hours at this Temperature held.

The polyaminopolyphenylmethanes of the present invention are made from the reaction mixture obtained by extraction of the catalyst salts. The raw mix is in an extractor with batch or continuous operation with aniline and water added. The organic phase exists after sufficient extraction / aniline exchange from aniline, diaminodiphenylmethane isomers and polyamines; the aqueous phase consists from the aniline and polyamine salts of the hydroxyethanesulfonic acid catalyst used in the reaction. A concentrated one is obtained by removing the water from the aqueous phase Catalyst salt that is suitable for use in further condensation reactions is (reuse catalyst). After adequate treatment (extraction with Water and aniline), the aniline can be drawn off from the organic phase, whereby a polymeric amine with diaminodiphenylmethane isomers remains. Is a breakup of If diamine is desired from the polyamine, the diamine will become the non-volatile one Polyamine residue drawn off by flash evaporation. The product caught upside down is removed e.g. at about 170 to 200 ° C at a pressure of 0.5 to about 0.025mm Hg and consists essentially of diaminodiphenylmethane.

The dimeric and higher products of the present invention are for suitable for a variety of uses. For example, they can be used as raw materials for manufacturing the corresponding polyisocyanates or used as curing agents for epoxides will.

When using hydroxyethanesulphonic acid, the results are compared with the other known catalysts, especially methanesulfonic acid and hydrochloric acid many surprising benefits.

For example, it has been found that the salts of hydroxyethane sulfonic acid (HESA) are more soluble than the corresponding aniline salt of methanesulfonic acid (MSA), which results in lower solid formation. During heating, after all of the formaldehyde has been added the physical properties are of the reaction mixture with HESA as a catalyst due to the lower solids formation better than with MSA. It was also found that HESA extract better with water is as MSA. Ultimately, these are the physical properties of what is recovered Catalyst is better in the case of HESA than in the case of MSA, since the former is at room temperature is a liquid, while the latter tends to solidify and therefore the next Use in the reactor is more difficult to handle.

The following examples serve to illustrate the invention Procedure.

Example 1 256 ml of aniline (2.7 mol) were placed in a cylindrical, given double-walled reactor with stirrer. Then a 75o meq HESA was added Solution of 2-hydroxyethanesulfonic acid (HESA) added (143.8 g of HESA solution were added. with 5.215 meq / g or 135 g 70 goat HESA + 8.8 g H20 or 94.5 g pure HESA (o, 75 mol) and 48.3 g H2O). No solids occurred at 180C - it will be all over again advised that when using methanesulfonic acid (MSA) or HCl with approximately the same water concentration during the initial formation of the catalyst salt Solids would have occurred.-The formalin addition was at reactor temperature started from 18-190c (turbo stirrer) and continued for 14 min to completion; added were 113 ml of formaldehyde (1.5 mol).

The temperature rose to 640C during the addition and after about 2/3 of the formalin was added, finely dispersed solids formed. These solids settled during the addition of the last portion of formula and when subsequently heated to 80 ° C, it is easier to handle than with MSA or HOl would have been the case as a catalyst. The reaction mixture was at 80 ° C. for 1 h held; thereafter, apart from a few traces, there were no more solids present. That The reaction mixture was heated further to 95-96 ° C. (under a slow stream of N2) and Maintained at this temperature for 2 h. This was followed by 50 ml portions of water at 28-3o0C added to the reactor liquid until it became cloudy (300 ml H20), the mixture was left to stand overnight to separate the different phases. 592 meq of acid became in the aqueous phase and 149 meq in the organic phase proven. The treatment of the organic phase with water and aniline lowered the acid content to about 10.8 meq total acid, starting from 750 meq used Acid. The organic phase has now been "neutralized", i.e. after neutralization was washed 3-4 more times with water to ensure the amine product was free of salts is. Thereafter, the water and aniline were stripped off, whereupon the amine product remained. The product had a total amine content of 9.9o mAq / g and a tertiary amine content of 0.058 meq / g. The amine product was at 65-70 ° C Completely soluble in chlorobenzene at a content of 6% and contained about 37.6 Weight% MDA (methylenedianiline) (determined by GLC). The gLC analysis also showed that the dimeric portion of the polyamine has only a trace of the 2,2'-isomer, 5.7% / 0 2,4'-isomer and contained 94.3% 4,4'-isomer. The GPC data (A%) showed the product to be 35 % consisted of dimers, 27% of trimers and 38% of higher homologues. That NMR showed essentially complete conversion and the absence of protons of the N-bensyl type. The extraction data from several comparative experiments showed that HESA is more extractable than MSA or HCl. Still remained with the recovery the HESA catalyst after the enrichment is liquid, while the MSA catalyst solidifies at the same concentration.

Example 2 Example 2 was made according to that described in Example 1 Method carried out, but 402 g of aniline (4.32 mol) with 2o3.4 g of a 74.4 frigen HESA solution (25.6 ° / H20), the 5.902 meq / g acid corresponding to 1200 meq Contained total acid, mixed and then treated with 180 ml of formazine (2.4 mol). The product was neutralized and had a total amine content of 9.89 meq / g and a tertiary amine content of 0.05 meq / g.

The physical properties of the reaction mixture were both during the addition of formalin as well as after the addition and during the heating excellent. The GPC (A%) showed 49 ° / dimer, 25 ° trimer and 26% higher homologues. The GLC showed 51.0% by weight of MDA and 95.4% by weight of 4,4'-isomer in the dimer fraction.

Example 3 In this example, those described in Example 1 were followed Method aniline and formaldehyde in a molar ratio of 1.9: 1 together with 62.5 mol.% HESA, based on formaldehyde, used. In addition, 56 ml of H20 (in addition to the amount of water in the 70% HESA solution) per mole of HESA. The formalin was added over a period of 25 minutes at 34-58 ° C. The reaction mixture was heated to 80 C, kept at this temperature for 1 hour and then at 95-97 ° C for 3 hours heated. The neutralized amine product was washed with water and drained. The analysis showed a total amine content of 9.97 meq / g and a content of tertiary Amine of 0.03 meq / g. The amine product was soluble to form 69b in chlorobenzene at 55-60 ° C. GPC (A96) showed 56 dimers, 25% trimer and 19C / o higher homologues. GLC showed 56.7 Wt. °, b MDA and 96.4 94 4,4'-isomer in the dimer fraction. NMR showed none rearranged protons of the N-benzyl type and only 0.6% (A%) protons of the N-CH3 type.

Example 4 In this example, the amine from Example 1 was mixed with phosgene implemented and obtained a high quality polymeric isocyanate.

Example 5 Several attempts were made with hydrochloric acid and methanesulfonic acid as catalysts in place of the catalyst according to the invention, hydroxyethanesulfonic acid, made. The following observations were made during the comparative experiments.

In the initial stage of the aniline-formaldehyde conversion (after approximately two thirds of the formaldehyde had been added to the aniline and catalyst) when using hydroxyethane sulfonic acid, the solids are finer and finer at 50-70 ° C softer i.e. easier to handle than hydrochloric acid or methanesulfonic acid. when using hydroxypropylsulfonic acid it was found that the physical Properties of the reaction mixture with hydroxyethanesulfonic acid as a catalyst were better.

After the reaction was over, the catalyst was extracted by extraction recovered with water as aniline or MDA salt. When using hydroxyethane sulfonic acid the extraction was much more effective than using methanesulfonic acid or hydrochloric acid, i.e. when using hydroxyethanesulfonic acid, you could use a a certain amount of water more catalyst can be extracted or fewer extractions with water were sufficient to completely remove the catalyst than when using of methanesulfonic acid or hydrochloric acid.

Ultimately, it was the recovered hydroxyethanesulfonic acid catalyst Much more soluble during enrichment and less prone to solidification than the corresponding salts of methanesulfonic acid and hydrochloric acid.

Claims (2)

Claims for the production of diaminodiphenylmethane and we side higher homologues through condensation of aniline and formaldehyde in Presence of a catalyst that is not indicated as Hydroxyethanesulfonic acid catalyst used and the catalyst by extraction its salt is recovered with water. 2. The method of claim 1, d a d u r c h g e -k e n n z e i c Note that the condensation occurs in the presence of about 10- about 70 mol%, preferably in the presence of 20-40 mol%, based on the aniline used.