DE19724237A1 - Production of aromatic poly:amine mixtures - Google Patents

Abstract

Production of aromatic polyamine mixtures contg. cpds. of formula: H2NACH2BNH2(I) (where, A and B = 1,4-phenylene residues which can have 1-4 substits. chosen from 1-20C alkyls and halogens) comprises converting a cpd. of formula: HANHCH2NHBH (IV) and/or a cpd. of formula HANHCH2BNH2 (V) (where, A and B = as above) at a temp. of 20-200 deg C in the presence of a heterogeneous inorganic catalyst chosen from: (a) oxides of 3-10 group element which can be acid-activated; (b) a clay doped with an oxide of a 2-13 group element or lanthanide which an be acid-activated; and (c) opt. acid-activated layered silicates acidity of below pK3 = 0.5 of more than 0.05 mmol/g catalyst.

Description

The invention relates to a process for the production of aromatic Polyamine mixtures of optionally substituted aniline and formaldehyde or formaldehyde precursors or a condensation product of these ver bonds.

Diaminodiarylmethanes, which are optionally substituted, are valuable Primary products, especially for the production of plastics. Above all that unsubstituted diaminodiphenylmethane (often called methylenedianiline, MDA is manufactured technically in very large quantities and largest partly, after phosgenation to methylene diphenyl diisocyanate (MDI), for which Manufacture of polyurethanes used. This is preferably the 4,4'-isomers are used, but arise in the known production processes also the 2,4'- and 2,2'-isomers. In addition, more condensed, more solid connections formed. The production usually takes place from Aniline and formaldehyde in the presence of catalysts.

In the technically practiced processes, inorganic acids are used in dissolved form used as homogeneous catalysts. It is preferred aqueous hydrochloric acid used. This reaction leads through the Auf work requires the consumption of equimolar amounts of bases, since the Acids neutralized when isolating the desired polyamines Need to become. This process is therefore inevitable with a seizure associated correspondingly high amounts of salt that must be disposed of or  be laboriously returned. Furthermore, the water with the use acid problems associated with corrosion are a major disadvantage this procedure.

For this reason, there have been numerous considerations and attempts to achieve this to replace aqueous homogeneous catalysts by acidic heterogeneous contacts. In addition to acidic ion exchangers, the use of acidic syntheti or natural silicon or aluminum oxides, such as zeolites or Clay minerals suggested. In DE-A-12 30 033, DE-A-14 93 431, US 4,071,558, US 4,039,580, US 4,039,581, US 4,294,987 are corresponding Described catalysts.

According to DE-A-12 30 033, acid-washed silicon-containing clay is a synthetic silica-alumina catalyst or a magnesium oxide-alumina catalyst used. The proportion of 2,4'-isomers in the However, product is high.

According to DE-A-14 93 431 silicon dioxide, silicon dioxide / aluminum oxide or acid-treated aluminum oxide used as a catalyst. Prefers are silica gel or bentonite-like clay, the silicon dioxide and aluminum contains oxide and is preferably acid activated. In addition to the desired diaminodiarylmethanes, however, higher condensation falls products to a considerable extent.

According to US 4,071,558, an acid-activated silicate clay catalyst sator, a silica-alumina cracking catalyst or a silicon Dioxide-magnesium oxide catalyst used. Here too fall at Verwen Formation of the clay catalyst larger amounts of 2,4'-isomers and higher moles specific products.  

According to US 4,039,580, US 4,039,581 and US 4,294,987 a mixture from diaminodiarylmethanes and higher condensed oligomers in complex received two-stage procedure. In addition to aqueous acids Diatomaceous earth, clays or zeolites are used.

According to US 4,294,987, the condensation in the presence of a strong performed aqueous acid, after which the solvent extraction Acid is removed. The rearrangement is again in the presence of strong acid, which is used in smaller quantities. Also Diatomaceous earth, clays or zeolites can be used in this stage the.

According to US 4,039,580 a condensation of aniline and formaldehyde run in the absence of a catalyst and the condensation product implemented in the presence of diatomaceous earth, clays or zeolites. Of the Diamond content in the product is 44 to 50%. In US 4,039,581 similar implementations are described. Technically, these catalysts have however due to the high prices, insufficient activities or cannot enforce the lack of catalyst life. High proportions of 4,4'-isomers and very low levels of higher condensed products are not accessible in these procedures. Bigger and bigger are falling Proportions of 2,4'- or 2,2'-isomers.

There is therefore still a demand for heterogeneous catalysts, which are inexpensive, have a high level of activity and have a long service life, are environmentally compatible and too high yields of 4,4'-isomers at gerin amounts of higher condensed products.

The object of the present invention is to provide catalysts, which have the aforementioned properties, and a method for Manufacture of aromatic polyamine mixtures.

According to the invention the object is achieved by a process for the preparation of aromatic polyamine mixtures which contain compounds of the general formula (I),

H ₂ NA-CH ₂ -B-NH ₂ (I)

in which A and B are 1,4-phenylene radicals, each of which may independently have 1 to 4 substituents selected from C _1-20 alkyl radicals and halogen atoms,
by reacting a compound of the general formula (IV)

HA-NH-CH ₂ -HN-BH (IV)

and / or a compound of the general formula (V)

HA-NH-CH ₂ -B-NH ₂

where A and B are substituted as defined above,
at a temperature in the range from 20 ° C. to 200 ° C. in the presence of a catalyst from one or more optionally acid-activated layer silicates which have an acidity below pK _s = 1.5 of more than 0.05 mmol / g catalyst.

The compound of general formulas (IV) and / or (V) can be substituted with aniline by reacting optionally on the aromatic nucleus in the o- or m-position with 1 to 4 substituents selected from C _1-20 alkyl radicals or halogen atoms Formaldehyde or formaldehyde precursors can be obtained.

In addition, the object is achieved by a process for the preparation of aromatic polyamine mixtures which contain compounds of the general formula (I)

H ₂ NA-CH ₂ -B-NH ₂ (I)

in which A and B are 1,4-phenylene radicals, each of which can independently have 1 to 4 sub-substituents selected from C _1-20 alkyl radicals and halogen atoms,
by reacting optionally on the aromatic nucleus in the o- or m-position with 1 to 4 substituents selected from C _1-20 alkyl radicals and halogen atoms, substituted anilines with formaldehyde or formaldehyde precursors at a temperature in the range from 20 ° C. to 200 ° C in the presence of a catalyst from one or more optionally acid-activated layered silicates which have an acidity below pK _s = 1.5 of more than 0.05 mmol / g catalyst.

It was found according to the invention that only when using certain th layered silicates sufficiently high yields of the desired 4,4'-di aminodiarylmethanes can be obtained. In the case of a layer not according to the invention Silicates also form the polyamine mixtures, but first, much slower and second, with the be in the above  Disadvantages described patent such as low 4,4'-selectivity and formation of more highly condensed compounds.

Catalysts which do not have these deficiencies are distinguished by the fact that, when titrated against Hammett indicators, especially the Ham mett indicator 4-phenylazo-diphenylamine (pK _s = 1.5), as in Tanabe et al., New Solid Acids and Bases, Stud. Surf. Sci. Catal. 51, 1989, Chapter 2, and Benesi, J. Phys. Chem. 61, 1957, pp. 970-973, described in more detail, have an acidity of more than 0.05 mmol butylamine per gram of catalyst. In order to determine the acidity of the dried catalyst in an inert aprotic solvent such as toluene is suspended and the indicator with the defined _pK a value of 1.5 as well as n-butylamine or a similar base is added. Since the reaction of the solid acid with the base takes place slowly, it is not possible to titrate in the usual way using a burette, but increasing amounts of base are added in several batches, shaken overnight, and it is checked the next morning after equilibrium has been reached at which base quantities the transshipment took place. This thus results in a quantitative amount of acidic sites in base mmol per gram of solid acid below the _pK a value of the indicator of 1.5.

All di- or trioctaedri come as layer silicates for the catalysts Representatives in question, such as kaolin, talc, pyrophylite, smectites such as hecto rit or montmorillonite, vermiculite, muscovite, sepiolite or attapulgite. Saponite, hectorite, montmorillonite, sepiolite and attapulgite are preferred. Montmorillonite, sepiolite and attapulgite are particularly preferred. The clays can be either natural or synthetic. For the It is irrelevant to catalysis whether it is a single defined layer is silicate or a mixture of different layered silicates. In particular  those when using naturally occurring layered silicates are common different layered silicates present at the same time.

The layered silicates can either already have a sufficient acidity below pK _s = 1.5 in their naturally occurring form or after a previous acid activation. They therefore contain different amounts of alkali and alkaline earth metal ions as well as the impurities such as iron ions that are always present in natural clays. If an acid activation is necessary to achieve a sufficiently high acidity, this can be done with different acids. The usual mineral acids such as hydrochloric acid, sulfuric acid or phosphoric acid are preferred. Hydrochloric acid is particularly preferred. Acid-activated layered silicates are commercially available under the names bleaching earth or fuller earths.

The catalysts can be in powder form or in the form of moldings, such as Strands, granules, tablets, pellets or balls can be used. Ent speaking the implementation in suspension mode or with a fixed bed catalysts are carried out. The implementation can be done in all Cases are carried out discontinuously or continuously.

According to one embodiment of the process according to the invention, optionally on the aromatic nucleus in the o- or m-position with 1 to 4 substituents selected from C _1-20 -, preferably C _1-10 -, particularly preferably C _1-6 -, in particular C _1-3 alkyl radicals and halogen atoms, preferably fluorine, chlorine or bromine atoms, in particular chlorine atoms, substituted aniline reacted with formaldehyde or formaldehyde precursors.

The optionally substituted aniline is preferably 0 to 2, particularly preferably none or a substituent. If there is a substituent, then so it is preferably an alkyl radical, in particular a methyl, ethyl or  Propyl residue. This substituent is preferably in the o-position. Compounds used with preference are aniline or o-toluidine. The given if substituted aniline is pre-formaldehyde or formaldehyde implemented runners. Such compounds serve as formaldehyde precursors, which release formaldehyde under the reaction conditions. Examples of this are paraformaldehyde and trioxane.

The reaction can be carried out directly in the presence of the invention Be carried out catalyst, d. H. the catalyst is already too Added start of implementation. For example, the given if substituted aniline submitted together with the catalyst and the Gaseous formaldehyde or as an aqueous solution or as formaldehyde Precursors are added. The implementation can also be carried out by the formaldehyde or the formaldehyde precursor with the given if substituted aniline submitted together and then connect the catalyst is entered. According to this further embodiment of the inven The first step is the formaldehyde with the optionally substituted one Aniline implemented in the absence of the catalyst, a Kon formation compound of the general formula (IV) or (V). This Pre-condensate can then in the presence of the Kataly sators are implemented, the rearrangement to connect the general formula (I) occurs.

The water of reaction formed during the formation of the precondensate can be removed continuously. It can also be used at the end of the implementation Formation of the precondensate can be removed by distillation or in Reaction mixture remain.

If an optionally substituted aniline is used in which both o-positions are not substituted, the 2,4'-isomers of the formula (II) and the 2,2'-isomers of the formula (III) are formed. The invention thus also relates to a process in which the aromatic nuclei are not substituted in at least one o-position to the amino group and the aromatic polyamine mixtures also contain compounds of the general formulas (II) and / or (III)

H ₂ ND-CH ₂ -B-NH ₂ (II)

in which D is a 1,2-phenylene radical and B is a 1,4-phenylene radical which, as above, the aromatic nuclei can be substituted,

H ₂ ND-CH ₂ -E-NH ₂ (III)

in which D and E are 1,2-phenylene radicals, which are the aromatic ones as above Cores can be substituted.

By using the catalysts of the invention, the proportion of Compounds of formula (I) compared to the proportion of the compounds of Formulas (II) and (III) can be varied in a targeted manner. Compounds of formula (III) are only formed to a very minor extent. The molar ratio of Compounds of formula (I) to compounds of formula (II) preferably more than 4 if compounds of the formula (II) are formed can be.

The implementation according to the invention, in particular the rearrangement reaction, runs preferably in the temperature range from 20 ° C to 200 ° C, particularly preferably from 70 ° C to 150 ° C. The implementation can be done in absentia or in the presence of a solvent. As a solution protic solvents such as alcohols and diols such as  Glycol, or aprotic solvents such as N-methylpyrrolidone are used. The reaction is preferably carried out in the absence of a solvent carried out.

The implementation is usually carried out without pressure, but can also be carried out under vacuum or overpressure. The implementation time is - depending on the temperature - preferably 10 minutes to 10 hours, particularly preferably 0.5 to 5 hours in a batch mode. The The amount of catalyst used is 1 to 50, preferably 5 to 40 % By weight, based on the weight of the precondensate. With continuous Operation is preferably a catalyst load of 0.1 to 1 l Starting mixture / l catalyst × h driven. The molar ratio of the given optionally substituted aniline to formaldehyde is preferably 2 to 50, particularly preferably 2.5 to 10.

For working up, the reaction mixture is - in the suspension procedure Filter off the catalyst powder - distillatively from any present the solvent or unreacted, optionally sub substituted aniline, and then freed of any high-boiling residue distilled off. The one obtained as a distillate Polyamine mixture can be used directly in subsequent reactions, such as phosgenation or also core hydrogenation.

The invention is explained in more detail below with the aid of examples. The parts indicated mean parts by weight.  

Catalyst production Catalyst A (comparative example)

Catalyst A was a commercially available acid-activated montmorillo nit from Südchemie (type: KSF) without acidic centers below pK _s = 1.5.

Catalyst B

Catalyst B was a commercially available acid-activated montmorillonite from Südchemie (type: K 10) with an acidity of 0.061 mmol g ^-1 below pK _s = 1.5.

Catalyst C

Catalyst C was a commercially available attapulgite from floridine.

Catalyst D (comparative example)

Catalyst D was obtained by acid activation (0.5 MH ₂ SO ₄ , 12 h 50 ° C) of a commercially available oxymine sepiolite. He had no acidity below pK _s = 1.5.

Catalyst E (comparative example)

Catalyst E was obtained by acid activation (1 M HCl, 24 h 50 ° C) of a commercially available sepiolite from Sobrep. It had no acidity below pK _s = 1.5.

Catalyst F

Catalyst F was obtained by acid activation (1 M HCl, 4 h 50 ° C.) of a commercially available montmorillonite (Terrana D from Südchemie). It had an acidity of 0.090 mmol g ^-1 below pK _s = 1.5.

Catalyst G (comparative example)

Catalyst G was obtained by acid activation (0.5 MH ₂ SO ₄ , 6 h 50 ° C) of a commercially available synthetic hectorite (Laponit RD from Laporte). It had an acidity of 0.021 mmol g ^-1 below pK _s = 1.5.

Catalyst H

Catalyst H was obtained by acid activation (0.5 MH ₃ PO ₄ , 12 h 50 ° C) of a commercially available montmorillonite (Terrana D from Südchemie). It had an acidity of 0.10 mmol g ^-1 below pK _s = 1.5.

Catalyst I

Catalyst I was obtained by acid activation (0.5 MH ₂ SO ₄ , 6 h 100 ° C) of a commercially available montmorillonite (Terrana D from Südchemie). It had an acidity of 0.10 mmol g ^-1 below pK _s = 1.5.

Catalyst J (comparative example)

Catalyst J was obtained by acid activation (1 M HCl, 24 h 50 ° C.) of a commercially available vermiculite (micro from Ziegler). It had an acidity of 0.031 mmol g ^-1 below pK _s = 1.5.

Catalyst K (comparative example)

Catalyst K was a commercially available Sobrep sepiolite. It had an acidity of 0.004 mmol g ^-1 below pK _s = 1.5.

Catalyst L (comparative example)

Catalyst L was a commercially available synthetic hectorite (Lapo nit RD from Laporte). It had no acidity below pK _s = 1.5. The example shows that catalysts with inadequate acidity can achieve sales in sufficient amounts, but at the same time the isomer ratio deteriorates.

Catalyst M

Catalyst M was a commercially available oxymine sepiolite. It had an acidity of 0.05 mmol g ^-1 below pK _s = 1.5.

Catalyst N (comparative example)

Catalyst N was a commercially available hectorite (Bentone MA from Rheox). It had no acidity below pK _s = 1.5. The example shows that although catalysts with insufficient acidity can achieve sales in sufficient amounts, the isomer ratio deteriorates at the same time.

Reaction to polyamines

160 g (1.5 mol) of o-toluidine were mixed with 7.5 g (0.25 Mol) formaldehyde (as a 37% aqueous solution) added, then the water was removed using a water separator at 150 ° C. The obtained solution of this precondensate in toluidine was used directly for the Implementation with the catalysts used.

For this purpose, 40% by weight (based on the adduct Formaldehyde and two molecules of toluidine) catalyst in powder form added and the mixture heated to 100 ° C. with stirring. The Results with the different catalysts after different reac tion times are shown in Table 1. A content of about 30% Tolui dinbase corresponds to the maximum possible yield. The specified Isomer ratio gives the proportion of the 4,4'-isomer relative to the 2,4'- Isomers again.  

Claims (10)

1. Process for the preparation of aromatic polyamine mixtures which contain compounds of the general formula (I),
H ₂ NA-CH ₂ -B-NH ₂ (I)
in which A and B are 1,4-phenylene radicals, each of which can independently have 1 to 4 substituents selected from C _1-20 alkyl radicals and halogen atoms,
by reacting a compound of the general formula (IV),
HA-NH-CH ₂ -HN-BH (IV)
and / or a compound of the general formula (V),
HA-NH-CH ₂ -B-NH ₂ (V)
where A and B are substituted as defined above,
at a temperature in the range from 20 ° C. to 200 ° C. in the presence of a catalyst composed of one or more optionally acid-activated sheet silicates which have an acidity below pK _s = 1.5 of more than 0.05 mmol / g catalyst. 2. The method according to claim 1, characterized in that the connec tion of the general formulas (IV) or (V) by reaction of optionally on the aromatic nucleus in the o- or m-position with 1 to 4 substituents selected from C _1-20 -Alkyl radicals or halogen atoms, substituted aniline with formaldehyde or formaldehyde precursors is obtained. 3. Process for the preparation of aromatic polyamine mixtures which contain compounds of the general formula (I)
H ₂ NA-CH ₂ -B-NH ₂ (I)
in which A and B are 1,4-phenylene radicals, each of which can independently have 1 to 4 substituents selected from C _1-20 alkyl radicals and halogen atoms,
by reacting optionally on the aromatic nucleus in the o- or m-position with 1 to 4 substituents selected from C _1-20 alkyl radicals and halogen atoms, substituted anilines with formaldehyde or formaldehyde precursors at a temperature in the range from 20 ° C. to 200 ° C in the presence of a catalyst from one or more optionally acid-activated phyllosilicates which have an acidity below pK _s = 1.5 of more than 0.05 mmol / g catalyst. 4. The method according to claim 2 or 3, characterized in that the water formed during the reaction is continuously removed. 5. The method according to any one of claims 1 to 4, characterized in that the aromatic nuclei are unsubstituted in at least one o-position to the amino group and the aromatic polyamine mixtures further contain compounds of the general formulas (II) and / or (III) ,
H ₂ ND-CH ₂ -B-NH ₂ (II)
in which D is a 1,2-phenylene radical and B is a 1,4-phenylene radical which can be substituted as defined in claim 3,
H ₂ ND-CH ₂ -E-NH ₂ (III)
in which D and E are 1,2-phenylene radicals which can be substituted as defined in claim 3. 6. The method according to claim 2, 3 or 4 with reference to claim 2 or 3, characterized in that aniline or o-toluidine is used will. 7. The method according to any one of claims 1 to 6, characterized in that one or more optionally acid-activated as a catalyst Layered silicates from the group of saponites, hectorites, montmorillonites, Sepiolite or Attapulgite can be used. 8. The method according to any one of claims 1 to 7, characterized in that the compound of formula (I) is formed as the main product. 9. The method according to any one of claims 1 to 8, characterized in that the reaction is carried out in the absence of a solvent becomes.   10. Use of catalysts from one or more layered silicas which have an acidity below pK _s = 1.5 of more than 0.05 mmol / g catalyst and can be acid-activated in the preparation of aromatic polyamine mixtures as claimed 1 or 5 are defined.