Process for the production of di- and polyamines of the diphenylmethane series

Abstract

The invention relates to a production process for polyamines through condensation of aromatic amines with formaldehyde employing at least one solid zeolite catalyst partially or fully ion-exchanged to the protonic form which has been A) alkaline-treated, wherein the alkaline treatment is in case of BEA zeolites carried out in the presence of a pore-directing agent and in case of zeolites other than BEA zeolites in the presence or absence of a pore-directing agent,
or B) acid-treated without any alkaline treatment preceding or following said acid treatment, wherein the acid treatment is effected with an organic acid with chelating function.

Claims

1. A process for the preparation of di- and polyamines of the diphenylmethane series comprising rearranging a condensation product, wherein said condensation product is formed by reacting aniline and a methylene group-supplying agent, and wherein said condensation product is reacted in the presence of at least one solid zeolite catalyst which is partially or fully ion-exchanged to the protonic form and comprises A) at least one alkaline-treated zeolite catalyst, wherein the alkaline treatment of BEA zeolites is carried out in the presence of a pore-directing agent and the alkaline treatment of zeolites other than BEA zeolites is carried out in the presence or absence of a pore-directing agent.

2. The process according to claim 1, wherein said alkaline-treated zeolite catalyst A) is selected from the group consisting of: (i) zeolites other than BEA zeolites which have been alkaline-treated in the presence or absence of a pore-directing agent; (ii) BEA zeolites which have been alkaline-treated in the presence of a pore-directing agent; (iii) zeolites which have been acid-treated in a first step and alkaline-treated in a second step; (iv) zeolites which have been alkaline-treated in a first step and acid-treated in a second step; (v) zeolites which have been acid-treated in a first step, alkaline treated in a second step and acid-treated in a third step; and (vi) mixtures thereof.

3. The process according to claim 1, wherein said pore-directing agent comprises an alkylammonium cation having the general molecular formula .sup.+NR.sup.i.sub.4, wherein the four R.sup.i substituents can be the same or different and can be selected from the group consisting of organic substituents and hydrogen.

4. The process according to claim 1, wherein said at least one-solid zeolite catalyst comprises a FAU type zeolite.

5. The process according to claim 2, wherein said alkaline-treated zeolite catalyst A) comprises (i) a zeolite other than a BEA zeolite in which the alkaline treatment is carried out in a pH range of 10 to 15 using an alkali metal hydroxide solution at a temperature of from 10 C. to 100 C. for a period of from 0.1 minutes to 180 minutes with a zeolite loading of 5 g L.sup.1 to 400 g L.sup.1, in which L refers to the volume of the total reaction mixture.

6. The process according to 2, wherein said alkaline-treated zeolite catalyst A) comprises (ii) a BEA zeolite in which the alkaline treatment is carried out in a pH range of 10 to 15 using an alkali metal hydroxide solution at a temperature of from 10 C. to 100 C. for a period of from 0.1 minutes to 180 minutes with a zeolite loading of 5 g L.sup.1 to 400 g L.sup.1, in which L refers to the volume of the total reaction mixture.

7. The process according to claim 2, wherein said alkaline-treated zeolite catalyst A) comprises (iii) a zeolite in which the acid treatment is carried out using an aqueous solution of an organic acid with chelating function or an aqueous solution of a mineral acid having a concentration of 0.01 mol L.sup.1 to 1 mol L.sup.1 at a temperature of from 10 C. to 100 C for a period of from 0.25 hours to 100 hours.

8. The process according to claim 7, wherein said alkaline-treated zeolite catalyst A) comprises (iii) a zeolite in which the alkaline treatment following the acid treatment is carried out in a pH range of 10 to 15 using an alkali metal hydroxide solution at a temperature of from 10 C. to 100 C. for a period of from 0.1 minutes to 180 minutes with a zeolite loading of 5 g L.sup.1 to 400 g L.sup.1, in which L refers to the volume of the total reaction mixture.

9. The process according to claim 2, wherein said alkaline-treated zeolite catalyst A) comprises (iv) a zeolite in which the alkaline treatment is carried out in a pH range of 10 to 15 using an alkali metal hydroxide solution at a temperature of from 10 C. to 100 C. for a period of from 0.1 minutes to 180 minutes with a zeolite loading of 5 g L.sup.1 to 400 g L .sup.1, in which L refers to the volume of the total reaction mixture.

10. The process according to claim 9, wherein said alkaline-treated zeolite catalyst A) comprises (iv) a zeolite in which the acid treatment following the alkaline treatment is carried out using an aqueous solution of an organic acid with chelating function or an aqueous solution of a mineral acid having a concentration of 0.01 mol L.sup.1 to 1 mol L.sup.1 at a temperature of from 10 C. to 100 C. for a period of from 0.25 hours to 100 hours.

11. The process according to claim 2, wherein said alkaline-treated zeolite catalyst A) comprises (v) a zeolite in which both acid treatments are carried out using an aqueous solution of an organic acid with chelating function or an aqueous solution of a mineral acid having a concentration of 0.01 mol L.sup.1 to 1 mol L.sup.1 at a temperature of from 10 C. to 100 C. for a period of from 0.25 hours to 100 hours.

12. The process according to claim 11, wherein said alkaline-treated zeolite catalyst A) comprises (v) a zeolite in which the alkaline treatment between the acid treatments is carried out in a pH range of 10 to 15 using an alkali metal hydroxide solution at a temperature of from 10 C. to 100 C. for a period of from 0.1 minutes to 180 minutes with a zeolite loading of 5 g L.sup.1 to 400 g L.sup.1, in which L refers to the volume of the total reaction mixture.

13. The process according to claim 1, wherein the treatment of alkaline-treated zeolite catalysts A) is performed such that the zeolite catalyst obtained after completion of the treatment has a crystallinity as determined by X-ray diffraction analysis of at least 50% when compared to the parent zeolite catalyst before the respective treatment.

14. The process of claim 1, wherein said methylene group supplying agent is selected from the group consisting of aqueous formaldehyde solution, gaseous formaldehyde, para-formaldehyde, trioxane and mixtures thereof.

Description

DETAILED DESCRIPTION

(1) Without wishing to be bound by a theory, it is believed that these treatments aim to generate external surface area in the zeolite crystals while preserving the active site properties. This should lead to increased utilization of the catalyst volume, while the characteristic performance of a zeolite, i.e. the obtained 4,4-MDA/2,4-MDA ratio is retained.

(2) In particular, preferred zeolites A) used according to the process of the invention are selected from the group consisting of: (i) zeolites other than BEA zeolites which have been alkaline-treated in the presence or absence of a pore-directing agent; (ii) BEA zeolites which have been alkaline-treated in the presence of a pore-directing agent; (iii) zeolites which have been acid-treated in a first step and alkaline-treated in a second step; (iv) zeolites which have been alkaline-treated in a first step and acid-treated in a second step; (v) zeolites which have been acid-treated in a first step, alkaline treated in a second step and acid-treated in a third step; and (vi) mixtures thereof;
wherein any acid-treatment step is preferably affected by an organic acid with chelating function.

(3) Methylene group-supplying agents which can be used in the process for the preparation of di- and polyamines of the diphenylmethane series according to the invention include aqueous formaldehyde solution, gaseous formaldehyde, para-formaldehyde, trioxane and mixtures thereof. Aqueous formaldehyde solution is particularly preferred. For the process of the present invention, preferably aqueous formaldehyde of technical quality having a formaldehyde concentration of 30% by weight to 50% by weight is used; typically this technical formaldehyde solution contains methanol in a 0.1% by weight to 15% by weight range. It is also possible to use aqueous formaldehyde solutions which have a lower or a higher formaldehyde concentration than mentioned before.

(4) For the process according to the invention, aniline grades are preferably used that are largely free from aliphatic amines as minor and trace constituents (e.g. cyclohexylamine, dicyclohexylamine). For the process according to the invention, aniline with a purity of 99.5% is preferably used. In this context, the purity of the aniline refers to the purity of aniline freshly introduced into the process from an outside source (fresh aniline). As is well known in the art, the aniline which, in a process on an industrial scale, is actually reacted with the methylene group-supplying agent is usually a mixture of such fresh aniline and aniline streams which have been recycled from other parts of the process, the latter usually being less pure.

(5) In the context of the present invention, the expression organic acids with chelating function refers to organic Brnsted acids with at least two acidic sites in their protonated or deprotonated (i.e. as salt) form. Preferably, the acid is chosen from the group consisting of ethylene diamine tetra acetic acid (EDTA), citric acid, oxalic acid and mixtures thereof. Such acids are capable of leaching aluminium from the zeolite. Preferably, acids are chosen which are capable of leaching at least 5% of the aluminium present in total in the zeolite, as determined by ICP-OES, if 10 g L.sup.1 of the zeolite are subjected to a treatment of a 0.1 M aqueous solution of the acid at a temperature of 100 C. for 6 hours. The respective method has been described by W. Zamechek in Verified Synthesis of Zeolithic Materials (Eds: H. Robson, K. P. Lillerud), 2nd Ed., Elsevier, 2001, pp. 51-53.

(6) The process according to the invention is preferably performed in the absence of solvents.

(7) In a preferred embodiment of the invention, the methylene group-supplying agent is reacted with aniline in the absence of an acidic catalyst, whereby a (condensation) product is formed that can be given the alternative name of aminal and consists predominantly of N,N-diphenyl-methylenediamine. This condensation product is preferably separated from the water of reaction when using aqueous formaldehyde solution, gaseous formaldehyde or mixtures thereof with the other methylene group-supplying agents mentioned before by phase separation and may further be dehydrated before the further reaction is performed under catalysis, although such an additional dehydration step is not strictly necessary and can be dispensed with.

(8) In principle, the reaction of aniline and the methylene group-supplying agent to give the aminal can be performed also in the presence of a catalyst that causes the rearrangement to aminobenzylaniline (ABA) and/or the MDA isomers. However, the water that is released during the condensation reaction when using aqueous formaldehyde solution, gaseous formaldehyde or mixtures thereof with the other methylene group-supplying agents mentioned before reduces the activity and selectivity of the catalyst, as a consequence of which the successive version (aminal reaction.fwdarw.phase separation.fwdarw.rearrangement) is preferred.

(9) The aminal reaction is preferably performed continuously by metering aniline and formaldehyde solution in a molar ratio of aniline to formaldehyde of 1.7 to 100, preferably 1.8 to 50, particularly preferably 2 to 20, into a reactor, from which a reaction quantity of the same volume as the feed stream is continuously removed and sent for phase separation. A batchwise or semi-continuous process is also conceivable, whereby the aniline and formaldehyde are metered in the desired mixing ratio into a stirred batch reactor, from which the aminal that is reacted out is then sent for drying.

(10) The desired molar ratio of aniline to formaldehyde (A/F) for the rearrangement can be set at the time of the aminal reaction, optionally taking the drying losses into consideration. In principle, however, it is also possible to perform the aminal reaction at a lower molar A/F as desired and then to set the desired value immediately before the rearrangement using pure, dry aniline. The latter option allows the use of smaller apparatus at the aminal reaction and drying stages, leading to lower investment costs. Aniline recovered from reprocessing of the reaction mixture (recycled aniline) can also be used for restocking after condensation, which in the case of the operation using an excess of aniline is recovered from the fully rearranged MDA.

(11) The rearrangement can preferably be performed batchwise or continuously in a stirred-tank reactor, a series of stirred-tank reactors, in a tubular reactor (e.g. fixed-bed or fluidised-bed reactor) or in a combination thereof. Serial fixed catalyst beds are advantageously used. A mixture of aminobenzylanilines, aniline and small quantities of diaminophenylmethanes is preferably first obtained in a temperature range of 20 C. to 70 C., particularly preferably 40 C. to 60 C., depending on the catalyst used. To this end, the reaction mixture is preferably pumped over the fixed catalyst bed, whereby residence times of 0.2 to 2 hours are typically set. The optimum temperature for a selected catalyst and a desired isomer ratio in the aminobenzyl-anilines obtained is easily determined by means of preliminary tests.

(12) The reaction to MDA is completed using the same or another catalyst bed at an increased temperature of 70 C. to 200 C., particularly preferably of 70 C. to 160 C., whereby residence times of 0.2 to 48 hours, preferably 0.5 to 24 hours, particularly preferably 1 to 18 hours are typically set. The phrase another catalyst bed can describe either another catalyst bed having the same composition than the first catalyst bed, or another catalyst bed based on a different catalyst composition than the first catalyst bed or a combination thereof.

(13) On completion of the reaction, the reaction mixture obtained by the process according to the invention and after separation from the catalyst can be processed such that the excess aniline optionally contained in the mixture can be separated from the MDA isomers either continuously or batchwise by known methods such as distillation or crystallisation, for example, and recycled. The MDA isomers are then preferably sent for subsequent phosgenation.

(14) The solid zeolite catalysts used according to the invention can be referred to as hierarchical zeolites, i.e. zeolites which have been subjected to a defined post-synthetic design process (such as the treatments (i) to (v) referred to above) so as to result in zeolitic structures featuring at least one additional level of porosity besides the intrinsic micropore system characteristic of zeolites, as described in Catal. Today, 2011, 168, 3-16.

(15) The solid zeolite catalysts used according to the invention can be prepared from any known zeolite. The starting material zeolite, i.e. a zeolite which has not yet been subjected to a post-synthetic design process as described above (in the following also referred to as parent zeolite), can be chosen from any zeolite known in the art, that needs to be partially or fully detemplated in case an organic template was used during its hydrothermal synthesis. The parent zeolite may have been subjected to treatments other than the ones described in A) or B), including but not limited to calcination, ion-exchange, steaming and acid treatments with mineral acids. Preference is given to 3D-frameworks with 12 membered-ring pore openings such as FAU and BEA, especially FAU (faujasite).

(16) The acid treatment of zeolite type B) is preferably carried out by contacting the zeolite with aqueous solutions of organic acids with chelating character such as ethylene diamine tetra acetic acid (EDTA), citric acid, oxalic acid or mixtures thereof in a temperature range of from 10 C. to 100 C., a concentration range of from 0.01 mol L.sup.1 to 1 mol L.sup.1 for a period of from 0.25 hours to 100 hours. A semi-batch wise addition of the acids to the solution is preferred.

(17) The alkaline treatment of zeolite type A) (i) is preferably carried out in a pH range of 10 to 15, preferably 11 to 14, using alkali metal hydroxide solutions, preferably NaOH and/or KOH. Also ammonia or basic salts are feasible. Typical treatment conditions comprise contacting the zeolite with the basic solution in batch, semi-batch or continuous mode in a temperature range of from 10 C. to 100 C. for a period of from 0.1 minutes to 180 minutes with a zeolite loading of 5 g L.sup.1 to 400 g L.sup.1, L referring to the volume of the total reaction mixture. According to the invention, this alkaline treatment may take place in the presence of a pore-directing agent. These serve to stabilize the zeolite in the alkaline environment and prevent the amorphization of the crystalline framework. Suitable pore-directing agents are alkylammonium cations with the general molecular formula .sup.+NR.sup.i.sub.4, wherein the four R.sup.i substituents R.sup.1, R.sup.2, R.sup.3 and R.sup.4 can be the same or different and can be organic substituents or hydrogen. In particular, the four R.sup.i substituents can be any combination of branched/linear alkanes, alkenes, aromatics hydrocarbons and protons, with preference being given to R.sup.i=linear alkyl substituents with 1-3 carbon atoms. The counter ion X.sup. of the alkylammonium cation is preferably chosen from the group consisting of hydroxides, halides, sulphates, nitrates and alkoxydes, whereof hydroxides, chlorides, bromides and methanolates are preferred.

(18) The alkaline treatment of zeolite type A) (ii) is preferably carried out as described above for type (i) with the exception that the use of a pore-directing agent is mandatory.

(19) The acid treatment of zeolite type A) (iii) is preferably carried out as described above for zeolite type B), however, a chelating character is not mandatory for the acid employed. Accordingly, in addition to the acids mentioned above, mineral acids such as hydrochloric acid, nitric acid phosphoric acid are also applicable.

(20) This acid treatment is followed by an alkaline treatment, which is preferably carried out as described above for zeolite type (i). It is preferred to carry out this alkaline treatment in the absence of a pore-directing agent.

(21) The alkaline treatment and acid treatment of zeolite type A) (iv) is preferably carried out as described for zeolite type (iii) with the order of treatment steps being reversed.

(22) The acid treatment steps of zeolite type A) (v) are preferably carried out as described for zeolite type A) (iii). The alkaline treatment step between the two acid treatment steps is preferably carried out as described for zeolite type (i). It is preferred to carry out this alkaline treatment in the absence of a pore-directing agent.

(23) Furthermore, it is preferred that the respective treatment A) or B) is performed such that the zeolite obtained after completion of the respective treatment has a crystallinity as determined by X-ray diffraction analysis of at least 50% when compared to the parent zeolite before the respective treatment A) or B). Quantification of crystallinity by X-ray diffraction should be carried out according to the ASTM standard issued under the jurisdiction of D32.05 or equivalent methods with the ASTM standard being the prevailing method in case of any discrepancy.

(24) These solid zeolite catalysts can in principle be used both in powder form and in lump form, whereby the conventional industrial processes of tabletting, pelletising or extrusion, for example, can be used for moulding, optionally with the aid of moulding additives such as binders, porogens, lubricants, plasticisers and fillers, as further detailed in Sharon Mitchell et al., Chem. Soc. Rev., 2013, 42, 6094-6112. For industrial use in the continuous process, the catalyst is preferably used after moulding to run solid catalyst beds. In batch-wise operation the catalysts are preferably used in quantities of 0.1 wt. % to 50 wt. % relative to the reaction mixture, in continuous operation preferably in quantities of 0.01 kg to 100 kg aminal/(kg catalyst.Math.h), especially preferably in quantities of 0.025 kg to 40 kg aminal/(kg catalyst.Math.h). Different grades and geometries, etc. of catalysts can also be used during the course of the process.

EXAMPLES

(25) I. Preparation of Aminal

(26) I.1 Aminal A from Aniline/Formaldehyde Ratio of 3

(27) In a four-neck round-bottom flask charged with nitrogen, 150 g aniline were added and heated under stirring to a temperature of 80 C. Then, a further portion of 315.7 g aniline as well as 134 g of aqueous formaldehyde solution (37.1 wt.-% HCHO) were added dropwise via separate dropping funnels within 20 minutes. The suspension thus obtained was further stirred for 10 minutes and in the next step transferred to an evacuated separation funnel, in which the suspension was allowed to settle for 20 minutes. The aqueous phase was separated from the aminal phase, whereby the latter one was used as starting material for the catalytic runs described in the following examples.

(28) I.2 Aminal B from Aniline/Formaldehyde Ratio of 2.5

(29) The preparation was conducted in the same fashion compared to I.1 with the exception of applying 161.9 g formaldehyde solution (37.1 wt.-% HCHO).

(30) I.3 Aminal C from Aniline/Formaldehyde Ratio of 2

(31) The preparation was conducted in the same fashion compared to I.1 with the exception of applying 202.4 g formaldehyde solution (37.1 wt.-% HCHO).

(32) II. Preparation of Zeolite Catalysts

(33) Zeolites whose preparation is not described in the following were purchased from commercial sources and used as obtained.

(34) Modified zeolite catalysts were prepared from commercially available zeolites as listed in Table 1. Treatments were carried out in stirred glass reactors. After the treatments, zeolites were filtered off and washed three times with 1 L of deionized water. Lastly, all the zeolites were ion-exchanged to the ammonium form by suspending 10 g L.sup.1 of zeolite in a 0.1 M ammonium nitrate solution at room temperature for 8 hours. This procedure was repeated three times. The obtained solids were dried at 65 C. and heated to 550 C. for 5 h with a ramp rate of 5 C. min.sup.1 to obtain the protonic form of the zeolites.

(35) TABLE-US-00001 TABLE 1 Overview of synthesized catalysts. Code Catalyst Parent Zeolite Step Reactants Temperature Time II.1 FAU6-ATN0.15 Zeolyst CBV712 1 6.6 g of zeolite, 1.2 g of NaOH, 200 g of water 65 C. 0.5 h II.2 FAU6-ATN0.20 Zeolyst CBV712 1 6.6 g of zeolite, 1.6 g of NaOH, 200 g of water 65 C. 0.5 h II.3 FAU6-ATAW Zeolyst CBV712 1 6.6 g of zeolite, 1.6 g of NaOH, 200 g of water 65 C. 0.5 h 2 4 g of zeolite from step 1, 2.48 g of NaOH, 60 g of water 100 C. 6 h II.4 FAU15-AT0.05 Zeolyst CBV720 1 6.6 g of zeolite, 0.4 g of NaOH, 10.65 g of 65 C. 0.5 h tetrapropylammonium bromide, 200 g of water II.5 FAU15-AT0.10 Zeolyst CBV720 1 6.6 g of zeolite, 0.8 g of NaOH, 10.65 g of 65 C. 0.5 h tetrapropylammonium bromide, 200 g of water II.6 FAU15-AT0.15 Zeolyst CBV720 1 6.6 g of zeolite, 1.2 g of NaOH, 10.65 g of 65 C. 0.5 h tetrapropylammonium bromide, 200 g of water II.7 FAU15-AT0.20 Zeolyst CBV720 1 6.6 g of zeolite, 1.6 g of NaOH, 10.65 g of 65 C. 0.5 h tetrapropylammonium bromide, 200 g of water II.8 FAU15-AT0.25 Zeolyst CBV720 1 6.6 g of zeolite, 2.0 g of NaOH, 10.65 g of 65 C. 0.5 h tetrapropylammonium bromide, 200 g of water II.9 FAU15-AT0.30 Zeolyst CBV720 1 6.6 g of zeolite, 2.4 g of NaOH, 10.65 g of 65 C. 0.5 h tetrapropylammonium bromide, 200 g of water II.10 FAU15-AT0.45 Zeolyst CBV720 1 6.6 g of zeolite, 3.6 g of NaOH, 10.65 g of 65 C. 0.5 h tetrapropylammonium bromide, 200 g of water II.11 FAU15-ATN0.20 Zeolyst CBV720 1 6.6 g of zeolite, 1.6 g of NaOH, 200 g of water 65 C. 0.5 h II.12 FAU30-AT0.15 Zeolyst CBV760 1 6.6 g of zeolite, 1.2 g of NaOH, 10.65 g of 65 C. 0.5 h tetrapropylammonium bromide, 200 g of water II.13 FAU40-AT0.05 Zeolyst CBV780 1 6.6 g of zeolite, 0.4 g of NaOH, 10.65 g of 65 C. 0.5 h tetrapropylammonium bromide, 200 g of water II.14 FAU385-AT0.20 Tosoh HSZ-390HUA 1 6.6 g of zeolite, 1.6 g of NaOH, 10.65 g of 65 C. 0.5 h tetrapropylammonium bromide, 200 g of water II.15 BEA20-AT0.15 Tosoh HSZ-940HOA 1 6.6 g of zeolite, 1.2 g of NaOH, 10.65 g of 65 C. 0.5 h tetrapropylammonium bromide, 200 g of water II.16 BEA220-AT0.15 Tosoh HSZ-980HOA 1 6.6 g of zeolite, 1.2 g of NaOH, 10.65 g of 65 C. 0.5 h tetrapropylammonium bromide, 200 g of water II.17 MFI15-ATAW Zeolyst CBV3024E 1 6.6 g of zeolite, 4.8 g of NaOH, 200 g of water 65 C. 0.5 h 2 3 g of zeolite from step 1, 2.05 g of HCl (35% in water), 65 C. 6 h 298 g of water II.18 MFI25-ATN0.30 Zeolyst CBV5524G 1 6.6 g of zeolite, 2.4 g of NaOH, 200 g of water 65 C. 0.5 h II.19 MFI40-ATN0.20 Zeolyst CBV8014 1 6.6 g of zeolite, 1.6 g of NaOH, 200 g of water 65 C. 0.5 h II.20 MFI140-AT0.20 Zeolyst CBV28014 1 6.6 g of zeolite, 1.6 g of NaOH, 10.65 g of 65 C. 0.5 h tetrapropylammonium bromide, 200 g of water II.21 MFI1000-AT0.20 Tosoh HSZ-890HOA 1 6.6 g of zeolite, 1.6 g of NaOH, 10.65 g of 65 C. 0.5 h tetrapropylammonium bromide, 200 g of water II.22 MOR10-DAAT Zeolyst CBV21A 1 10 g of zeolite, 13.53 g HNO.sub.3 (65% in water), 100 C. 1 h 87 g of water 2 6.6 g of zeolite, 1.2 g of NaOH, 200 g of water 65 C. 0.5 h II.23 HEU5-DAAT KMI Zeolite 1 12 g of zeolite, 12.45 g HCl (35% in water), 170 g of water 100 C. 1 h Clinoptilolite 2 10 g of zeolite, 10.38 g HCl (35% in water), 142 g of water 100 C. 1 h 3 8 g of zeolite, 8.30 g HCl (35% in water), 113 g of water 100 C. 1 h 4 6 g of zeolite, 6.23 g HCl (35% in water), 85 g of water 100 C. 1 h 5 4 g of zeolite, 0.97 g of NaOH, 121 g of water 65 C. 1 h
II.24 Preparation Procedure for MCM-41 (Comparative Example)

(36) 0.612 g NaAlO.sub.2 were dissolved in 600 g H.sub.2O and 12 g of cetyltrimethylammoniumbromide were added. The suspension was stirred at 60 C. until complete dissolution occurred and cooled to room temperature before adding 45 g NH.sub.4OH (56 wt. % in H.sub.2O) and 46.7 g tetraethylorthosilicate. The precipitated solid was filtered after stirring for 1 h at room temperature and washed with deionized water. The filter cake was dried at 65 C. and heated to 550 C. for 10 hours under air flow with a ramp rate of 2 C. min.sup.1. The solid thus obtained was suspended in a solution of 2.64 g NH.sub.4NO.sub.3 in 330 g H.sub.2O for 8 h at room temperature. This procedure was repeated three times. The material thus obtained was dried at 65 C. and heated to 550 C. for 5 h with a ramp rate of 5 C. min.sup.1 to obtain MCM-41.

(37) II.25 Preparation Procedure for ITQ-2 Zeolites (Comparative Example)

(38) All materials were synthesized according to reported preparations (ZSM-22(P) synthesis according to A. Corma in Verified Syntheses of Zeolitic Materials (Eds: H. Robson and K. P. Lillerud), 2. Edition, Elsevier, 2001, pp. 225-227. Delamination procedure according to M. Salzinger, M. B. Fichtl, J. A. Lercher, Appl. Catal., A 2011, 393, 189-194.).

(39) For the synthesis of ITQ-2, the parent zeolite (ZSM-22) had to be prepared first. For this purpose, 248.4 g of water was mixed with 1.84 g sodium aluminate and 1.2 g of sodium hydroxide. 15.22 g hexamethyleneimine was added and the solution mixed throughly before 18.46 g of fumed silica was added portion wise. The obtained thick gel was transferred into an autoclave and incubated in a rotary oven at 150 C. and 60 rpm for 7 days. The catalyst was filtered off and washed with deionized water to obtain MCM-22(P)

(40) 5.4 g of MCM-22(P) were suspended in 99.5 g of H.sub.2O, 66.5 g of tetrapropylammonium hydroxide solution (20 wt. %) and 7.67 g of hexadecyltrimethylammonium bromide at 80 C. for 16 hours and introduced into an ultrasonic bath for 1 hour. Through addition of concentrated HCl, the pH was reduced to 2 and the solution filtered off. The obtained material was dried in static air at 100 C. and calcined at 550 C. for for 8 hours with a ramp rate of 2 C. min.sup.1. The obtained solid was suspended in a solution of 2.64 g NH.sub.4NO.sub.3 in 330 g H.sub.2O for 8 h at room temperature. This procedure was repeated three times, before calcination at 550 C. for 5 h with a ramp rate of 5 C. min.sup.1. The yield was 3.4 g.

(41) III. Catalytic Tests

(42) For running the catalytic experiments, a multi-batch reactor system (AMTEC, SPR-16) was used consisting of 16 parallel reactors with a volume of 15 mL each. Each reactor was pressurized with nitrogen, filled with the respective zeolite (0.1 to 1 g) and aminal (4.9 g, prepared as described under A). Agitation was achieved via magnetic stirring at 500 rpm and the system was heated up to a temperature of 140 C. After a reaction time that varied between 1 and 4 hoursin some cases 24 h, the reactors were cooled to room temperature. The suspension was filtered through a syringe filter and an aliquot from the filtrate was taken for HPLC analysis (Agilent 1100 Series), for which a mixture of methanol, water and acetonitrile was used as eluent and a phenomenex column as stationary phase. Applying a method with external 3-point calibration, the components mentioned in the next examples could be quantified. Prior to injection, the respective aliquot (approximately 50 mg) was diluted in an N-ethyldiisopropylamine solution of 50 mL (0.12% w/w in methanol/THF solution (1:2 w/w)) and transferred in a vial. For comparability, excess aniline was subtracted in the quantities given in the tables below.

(43) III.1 Examples 1 to 14 (Catalytic Runs with Faujasite and Beta Zeolites and Modifications Thereof)

(44) For the experiments in examples 1 to 14, aminal A was used, the catalyst amount was 0.1 g and the reaction time 4 h resulting in a load of 12.25 g.sub.Aminal/(g.sub.Catalyst.Math.h).

(45) TABLE-US-00002 TABLE 2 Overview of catalytic runs 1 to 14. ABAs.sup.2) MMDA.sup.3) PMDA.sup.4) Others.sup.5) 4,4-MDA/ III.1 Code.sup.1) % % % % 2,4-MDA 1 II.3 13.8 58.4 8.4 19.5 6.0 2 FAU6 45.7 20.8 0.7 32.8 6.0 3 II.7 8.2 69.5 7.3 15.0 6.6 4 FAU15 29.4 40.9 2.0 27.7 6.5 5 II.12 27.2 42.3 3.8 26.7 6.1 6 FAU30 30.2 38.9 1.9 29.0 6.0 7 II.13 31.5 37.8 2.1 28.7 5.5 8 FAU40 42.6 23.9 0.9 32.6 5.3 9 II.14 57.4 10.0 0.5 32.1 5.9 10 FAU385 58.9 2.4 0.0 38.7 5.3 11 II.15 4.0 69.9 10.8 15.3 2.9 12 BEA20 50.5 14.9 0.4 34.3 2.2 13 II.16 48.4 18.0 0.6 33.1 1.5 14 BEA220 54.7 7.8 0.2 37.3 1.9 .sup.1)Code refers to Chapter II, parent zeolite for reference without treatment, .sup.2)o- and p-ABA, .sup.3)4,4-, 2,4-, 2,2-, 4,4-N-Formyl- and 4,4-N-Methyl-MDA, .sup.4)3- and 4-ring isomers, .sup.5)5-ring and non identifiable products.

(46) Under the same reaction conditions, the modified catalysts revealed a higher content of MMDA compared to the parent samples without treatment. The space-time yield of MMDA is therefore increased.

(47) III.2 Examples 15 to 28 (Catalytic Runs with Heulandite, Mordenite, ZSM-5 and Modifications Thereof)

(48) For the experiments in examples 15 to 28, aminal A was used, the catalyst amount was 0.1 g and the reaction time 4 h resulting in a load of 12.25 g.sub.Aminal/(g.sub.Catalyst.Math.h).

(49) TABLE-US-00003 TABLE 3 Overview of catalytic runs 15 to 28 ABAs.sup.2) MMDA.sup.3) PMDA.sup.4) Others.sup.5) 4,4-MDA/ III.2 Code.sup.1) % % % % 2,4-MDA 15 II.23 47.0 16.8 1.3 34.9 5.0 16 HEU5 61.9 2.7 0.0 35.4 4.9 17 II.17 59.0 10.8 1.0 29.2 4.0 18 MFI15 58.1 5.7 0.2 36.0 3.5 19 II.18 20.7 48.1 6.2 25.0 4.7 20 MFI25 60.7 3.7 0.1 35.6 3.0 21 II.19 15.6 54.4 8.0 22.0 4.0 22 MFI40 54.0 10.2 0.2 35.5 4.1 23 II.20 59.5 5.1 0.1 35.3 3.0 24 MFI140 63.0 0.6 0.0 36.5 2.8 25 II.21 60.8 0.2 0.0 39.1 26 MFI1000 52.6 0.1 0.0 47.3 27 II.22 54.3 11.7 0.2 33.9 6.0 28 MOR10 63.3 2.2 0.1 34.4 3.2 .sup.1)Code refers to Chapter II, parent zeolite for reference without treatment, .sup.2)o- and p-ABA, .sup.3)4,4-, 2,4-, 2,2-, 4,4-N-Formyl- and 4,4-N-Methyl-MDA, .sup.4)3- and 4-ring isomers, .sup.5)5-ring and non identifiable products.

(50) Under the same reaction conditions, the modified catalysts revealed a higher content of MMDA compared to the parent samples without treatment. The space-time yield of MMDA is therefore increased.

(51) III.3 Examples 29 to 35 (Catalytic Runs with Faujasite-15 and Modifications Thereof)

(52) For the experiments in examples 29 to 35, aminal A was used, the catalyst amount was 0.1 g and the reaction time 1 h resulting in a load of 49.00 g.sub.Aminal/(g.sub.Catalyst.Math.h).

(53) TABLE-US-00004 TABLE 4 Overview of catalytic runs 29 to 35. ABAs.sup.2) MMDA.sup.3) PMDA.sup.4) Others.sup.5) 4,4-MDA/ III.3 Code.sup.1) % % % % 2,4-MDA 29 FAU15 37.9 30.1 1.0 31.0 6.6 30 II.4 26.9 44.1 2.3 26.8 6.8 31 II.5 26.6 44.2 2.3 26.9 6.9 32 II.6 22.7 48.7 2.9 25.6 7.1 33 II.7 15.3 60.1 4.9 19.7 7.1 34 II.8 13.0 63.3 5.5 18.2 7.1 35 II.9 11.1 66.2 6.2 16.5 7.1 .sup.1)Code refers to Chapter II, parent zeolite for reference without treatment, .sup.2)o- and p-ABA, .sup.3)4,4-, 2,4-, 2,2-, 4,4-N-Formyl- and 4,4-N-Methyl-MDA, .sup.4)3- and 4-ring isomers, .sup.5)5-ring and non identifiable products.

(54) Under the same reaction conditions, the modified catalysts revealed a higher content of MMDA compared to the parent sample without treatment. The space-time yield of MMDA is therefore increased.

(55) III.4 Examples 36 to 40 (Comparative, Catalytic Runs with ITQ-2, Amorphous Silica-Alumina and Mesoporous Silica (MCM-41))

(56) For the experiments in examples 35 to 39, aminal A was used, the catalyst amount was 0.1 g and the reaction time 4 h resulting in a load of 12.25 g.sub.Aminal/(g.sub.Catalyst.Math.h).

(57) TABLE-US-00005 TABLE 5 Overview of catalytic runs 36 to 40. ABAs.sup.2) MMDA.sup.3) PMDA.sup.4) Others.sup.5) 4,4-MDA/ III.4 Code.sup.1) % % % % 2,4-MDA 36 ASA 4.7 67.2 16.9 11.2 5.4 37 ITQ-2 11.0 60.1 6.8 22.0 3.7 38 ITQ-2 8.8 63.8 8.0 19.4 3.5 39 MCM41 40.0 24.4 3.4 32.2 4.8 40 MCM41 37.3 28.1 3.6 31.1 4.9 .sup.1)Code refers to Chapter II, parent zeolite for reference without treatment, .sup.2)o- and p-ABA, .sup.3)4,4-, 2,4-, 2,2-, 4,4-N-Formyl- and 4,4-N-Methyl-MDA, .sup.4)3- and 4-ring isomers, .sup.5)5-ring and non identifiable products

(58) The isomer ratio between 4,4-MDA and 2,4-MDA is comparably lower than for FAU types. Moreover, the reaction is incomplete.

(59) III.5 Examples 41 to 45 (Comparative, Catalytic Runs with ITQ-2, Amorphous Silica-Alumina and Mesoporous Silica (MCM-41))

(60) For the experiments in examples 41 to 45, aminal A was used, the catalyst amount was 1 g and the reaction time 4 h resulting in a load of 1.23 g.sub.Aminal/(g.sub.Catalyst.Math.h).

(61) TABLE-US-00006 TABLE 6 Overview of catalytic runs 41 to 45. ABAs.sup.2) MMDA.sup.3) PMDA.sup.4) Others.sup.5) 4,4-MDA/ III.5 Code.sup.1) % % % % 2,4-MDA 41 ASA 0.1 73.7 22.8 3.4 5.0 42 ITQ-2 0.1 75.2 19.1 5.7 3.6 43 ITQ-2 1.3 78.1 16.2 4.5 3.7 44 MCM41 45 MCM41 .sup.1)Code refers to Chapter II, parent zeolite for reference without treatment, .sup.2)o- and p-ABA, .sup.3)4,4-, 2,4-, 2,2-, 4,4-N-Formyl- and 4,4-N-Methyl-MDA, .sup.4)3- and 4-ring isomers, .sup.5)5-ring and non identifiable products.

(62) The isomer ratio between 4,4-MDA and 2,4-MDA is comparably lower than for FAU types. Whereas MCM41 revealed poor activity at 0.1 g, it was impossible to filter off the organic phase from the solid catalyst which makes the catalyst impractical for industrial use.

(63) III.6 Examples 46 to 49 (Catalytic Runs with Faujasite-15 and Modifications Thereof)

(64) For the experiments in examples 46 and 47, aminal A was used, the catalyst amount was 0.1 g and the reaction time 4 h resulting in a load of 12.25 g.sub.Aminal/(g.sub.Catalyst.Math.h). For the experiments in examples 48 and 49, aminal A was used, the catalyst amount was 1 g and the reaction time 4 h resulting in a load of 1.23 g.sub.Aminal/(g.sub.Catalyst.Math.h).

(65) TABLE-US-00007 TABLE 7 Overview of catalytic runs 46 to 49. ABAs.sup.2) MMDA.sup.3) PMDA.sup.4) Others.sup.5) 4,4-MDA/ III.6 Code.sup.1) % % % % 2,4-MDA 46 FAU15 29.2 42.0 2.3 26.4 6.5 47 II.11 3.2 69.8 17.4 9.6 5.0 48 FAU15 0.1 83.8 14.7 1.4 7.3 49 II.11 0.2 75.7 21.9 2.2 5.2 .sup.1)Code refers to Chapter II, parent zeolite for reference without treatment, .sup.2)o- and p-ABA, .sup.3)4,4-, 2,4-, 2,2-, 4,4-N-Formyl- and 4,4-N-Methyl-MDA, .sup.4)3- and 4-ring isomers, .sup.5)5-ring and non identifiable products.

(66) A higher space-time yield on higher homologues of modified Faujasite-15 compared to the parent one was obtained.

(67) III.7 Examples 50 to 55 (Catalytic Runs with Faujasite-6 and Modifications Thereof)

(68) For the experiments in examples 50 and 55, aminal A was used, the catalyst amount was 0.1 g and the reaction time 1 h resulting in a load of 49.00 g.sub.Aminal/(g.sub.Catalyst.Math.h).

(69) TABLE-US-00008 TABLE 8 Overview of catalytic runs 50 to 55. ABAs.sup.2) MMDA.sup.3) PMDA.sup.4) Others.sup.5) 4,4-MDA/ III.7 Code.sup.1) % % % % 2,4-MDA 50 FAU6 55.3 10.1 0.2 34.4 6.3 51 FAU6 55.6 9.7 0.2 34.5 6.3 52 II.1 41.4 26.2 0.9 31.4 6.0 53 II.1 39.8 28.6 1.1 30.5 6.0 54 II.2 13.3 63.1 5.8 17.7 6.2 55 II.2 15.6 59.8 5.4 19.2 6.2 .sup.1)Code refers to Chapter II, parent zeolite for reference without treatment, .sup.2)o- and p-ABA, .sup.3)4,4-, 2,4-, 2,2-, 4,4-N-Formyl- and 4,4-N-Methyl-MDA, .sup.4)3- and 4-ring isomers, .sup.5)5-ring and non identifiable products

(70) A higher space-time yield on MMDA and higher homologues of modified FAU-6 compared to the parent one was obtained.

(71) III.8 Examples 56 to 72 (Catalytic Runs Varying A/F Ratio)

(72) For the experiments in examples 56 to 60, aminal C was used, the catalyst amount was 1 g and the reaction time 4 h resulting in a load of 1.23 g.sub.Aminal/(g.sub.Catalyst.Math.h). For the experiments in examples 61 to 66, aminal B was used, the catalyst amount was 1 g and the reaction time 4 h resulting in a load of 1.23 g.sub.Aminal/(g.sub.Catalyst.Math.h). For the experiments in examples 67 to 72, aminal A was used, the catalyst amount was 1 g and the reaction time 4 h resulting in a load of 1.23 g.sub.Aminal/(g.sub.Catalyst.Math.h).

(73) TABLE-US-00009 TABLE 9 Overview of catalytic runs 56 to 72. ABAs.sup.2) MMDA.sup.3) PMDA.sup.4) Others.sup.5) 4,4-MDA/ III.8 Code.sup.1) % % % % 2,4-MDA 56 FAU6 0.6 71.5 16.6 11.3 5.6 57 II.1 0.1 69.5 25.1 5.3 4.7 58 II.1 0.2 69.6 25.0 5.2 4.7 59 II.2 0.1 64.4 30.7 4.9 5.2 60 II.2 0.1 64.8 30.6 4.6 5.3 61 FAU6 0.0 77.1 18.6 4.3 6.7 62 FAU6 0.0 79.1 17.1 3.8 6.7 63 II.1 0.1 75.2 22.2 2.6 5.1 64 II.1 0.5 74.9 21.5 3.1 5.2 65 II.2 0.2 72.7 24.4 2.7 5.4 66 II.2 0.1 73.2 24.1 2.7 5.3 67 FAU6 0.0 82.7 15.7 1.6 6.4 68 FAU6 0.0 83.6 14.8 1.7 6.5 69 II.1 0.0 81.7 16.9 1.4 5.9 70 II.1 0.0 81.8 16.8 1.4 5.9 71 II.2 0.4 73.8 23.1 2.7 5.1 72 II.2 0.0 76.0 21.6 2.4 5.3 .sup.1)Code refers to Chapter II, parent zeolite for reference without treatment, .sup.2)o- and p-ABA, .sup.3)4,4-, 2,4-, 2,2-, 4,4-N-Formyl- and 4,4-N-Methyl-MDA, .sup.4)3- and 4-ring isomers, .sup.5)5-ring and non identifiable products

(74) At varying A/F ratio, a higher space-time yield on MMDA and higher homologues of modified FAU-6 compared to the parent one was obtained.