WO2014059574A1

WO2014059574A1 - Direct amination reaction to produce primary or secondary amine

Info

Publication number: WO2014059574A1
Application number: PCT/CN2012/082951
Authority: WO
Inventors: Mohamad OUSMANE; Marc Pera Titus; Floryan Decampo
Original assignee: Rhodia China Co Ltd; Centre National de la Recherche Scientifique CNRS; Rhodia Operations SAS
Current assignee: Solvay China Co Ltd; Centre National de la Recherche Scientifique CNRS; Rhodia Operations SAS
Priority date: 2012-10-15
Filing date: 2012-10-15
Publication date: 2014-04-24
Anticipated expiration: 2015-04-15

Description

DIRECT AMINATION REACTION TO PRODUCE PRIMARY OR SECONDARY AMINE

The present invention concerns a process for forming a primary or a secondary amine via a direct animation reaction comprising: reacting an alcohol with an amine in the presence of ordered porous manganese-based octahedral molecular sieves comprising a transition metal.

PRIOR ART

Direct amination of alcohols is a very attractive pathway to prepare primary, secondary or tertiary amines. Various techniques have been described in the literature but usually require stringent conditions such as high temperature or high pressure of hydrogen. Also, such catalyst typically yields mixtures with average or low selectivity making purification difficult. Some attractive homogeneous catalysts have been developed recently and showed an improved selectivity relying on the "borrowing hydrogen" mechanism, which allows running the reaction under milder conditions and without the addition of hydrogen. However, homogeneous catalysts are expensive and difficult to recycle.

It is known from Zhang et al. Tetrahedron Letters 52 (201 1) 1334-1338 the attractive properties of an iron oxide immobilized palladium catalyst for the N- alkylation of amines with alcohols. However this process leads also to tertiary amines in a significant amount.

Manganese octahedral molecular sieves (OMS) constitute a crystalline variety of amorphous manganese oxide (Mn0₂) with a well-defined microporous network and different oxidation states of manganese. Among the different crystalline manganese oxide families (S.L. Suib, Accounts Chem. Res. 41 (2008) 479 ; Q.

l Feng, H. Kanoh, K. Ooi, J. Mater. Chem. 41 (2008) 479), K-OMS-2 materials based on cryptomelane structure have proven excellent activities in the oxidation of alcohols (Y.C. Son, V.D. Makwana, A.R. Howell, S.L. Suib, Angew. Chem., Int. Ed. 9 (1999) 319.). Until now, the reported studies in K-OMS-2 materials point out the preferential generation of imines by N-alkylation of aromatic and aliphatic alcohols, but with no amine formation (S. Sithambaram, R. Kumar, Y-C. Son, S.L. Suib, J. Catal. 253 (2008) 269 ; S. Sithambaram, Y-C. Son, S.L. Suib, US Patent 7,355,075, 2008). INVENTION

It appears now that a notable synergistic effect was identified by a combination of ordered porous manganese-based octahedral molecular sieves with transition metals in order to produce a primary or a secondary amine via a direct amination reaction of an alcohol with an amine. Such a catalyst may be used to produce a primary or a secondary amine with a very high selectivity and a very good conversion of amine without generating tertiary amine. The present catalytic system appears then to be very active for direct amination reaction of alcohols under mild conditions. The present invention concerns then a process for forming a primary or a secondary amine via a direct amination reaction comprising reacting:

A first reactant having one or two primary hydroxyl functionalities with A second reactant being NH₃ or a reactant having primary amine functionality,

in the presence of ordered porous manganese-based octahedral molecular sieves comprising a transition metal of Group 8 to 11 elements of the Periodic Table; and at a temperature and for a time sufficient for the primary amine or the secondary amine to be produced. The present invention concerns furthermore this catalyst as such, i.e. ordered porous manganese-based octahedral molecular sieves comprising a transition metal of Group 8 to 11 elements of the Periodic Table. The present invention also concerns a primary or a secondary amine susceptible to be obtained by the process of the present invention.

The present invention also concerns a composition comprising at least an imine and a primary or a secondary amine, said composition is substantially free or, in some cases, completely free of tertiary amine. As used herein, the term "substantially free" when used with reference to the absence of tertiary amine in the composition of the present invention, means that the composition comprises less than 0.1 % wt of tertiary amine, based on the total weight of the composition. As used herein, the term "completely free" when used with reference to the absence of tertiary amine in the composition of the present invention, means that the composition comprises no tertiary amine at all.

Reaction of the present invention may notably be represented as follows:

(I) (Π) (III) (IV)

Wherein:

x is 1 or 2

- R¹ is H or a straight, branched or cyclic hydrocarbon group

R² is H or a straight, branched or cyclic hydrocarbon group

While not being bound by theory, it is believed that the reaction of a first reactant having one or two primary hydroxyl functionalities with a second reactant being H₃ or a reactant having a primary amine functionality leads to the formation of an imine and a subsequent production of a primary or a secondary amine. Definitions

"Alkyl" as used herein means a straight chain or branched saturated aliphatic hydrocarbon. Preferably alkyl group comprises 1-18 carbon atoms. Representative saturated straight chain alkyls include methyl, ethyl, n-propyl, n-butyl, n-pentyl, and the like; while saturated branched alkyls include isopropyl, sec-butyl, isobutyl, tert- butyl, isopentyl, and the like.

"Alkenyl", as used herein, refers to an aliphatic group containing at least one double bond and is intended to include both "unsubstituted alkenyls" and "substituted alkenyls", the latter of which refers to alkenyl moieties having substituents replacing a hydrogen on one or more carbon atoms of the alkenyl group. Representative unsaturated straight chain alkenyls include ethenyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl and the like.

The term "cyclic group" means a closed ring hydrocarbon group that is classified as an alicyclic group, aromatic group, or heterocyclic group. The term "alicyclic group" means a cyclic hydrocarbon group having properties resembling those of aliphatic groups.

"Aryl" as used herein means a 6-carbons monocyclic or 10-carbons bicyclic aromatic ring system wherein 0, 1, 2, 3, or 4 atoms of each ring are substituted. Examples of aryl groups include phenyl, naphthyl and the like. The term "arylalkyl" or the term "aralkyl" refers to alkyl substituted with an aryl. The term "arylalkoxy" refers to an alkoxy substituted with aryl. "Cycloalkyl" as used herein means cycloalkyl groups containing from 3 to 8 carbon atoms, such as for example cyclohexyl.

"Heterocyclic" as used herein means heterocyclic groups containing up to 6 carbon atoms together with 1 or 2 heteroatoms which are usually selected from O, N and S, such as for example radicals of : oxirane, oxirene, oxetane, oxete, oxetium, oxalane (tetrahydrofurane), oxole, furane, oxane, pyrane, dioxine, pyranium, oxepane, oxepine, oxocane, oxocinc groups, aziridine, azirine, azirene, azetidine, azetine, azete, azolidine, azoline, azole, azinane, tetrahydropyridine, tetrahydrotetrazine, dihydroazine, azine, azepane, azepine, azocane, dihydroazocine, azocinic groups and thiirane, thiirene, thiethane, thiirene, thietane, thiete, thietium, thiolane, thiole, thiophene, thiane, thiopyrane, thiine, thiinium, thiepane, thiepine, thiocane, thiocinic groups. "Heterocyclic" may also mean a heterocyclic group fused with a benzene-ring wherein the fused rings contain carbon atoms together with 1 or 2 heteroatom's which are selected from N, O and S.

First reactant having one or two primary hydroxyl functionalities

This first reactant may notably be a compound of formula (I) :

R¹(-CH₂-OH)x (I)

Wherein:

x is 1 or 2

- R¹ is H or a straight, branched or cyclic hydrocarbon group

R¹ may represent straight, branched or cyclic hydrocarbon group that can be an alkyl, alkenyl, aryl, cycloalkyl or heterocyclic group, eventually comprising one or several heteroatoms such as O, S, F, and N. Preferred groups for R¹ may be for example : H, alkyl, cyclic alkane, cyclic alkene, phenyl, furanyl, and tetrahydrofuranyl.

In addition the first reactant may comprise additional functionalities. The additional functionalities may behave as electron donating or electron withdrawing groups as long as their presence does not prevent reaction with the amine to form the imine. There is no particular limitation on the number of carbon atoms present in the reactant as long as its structure does not prevent the formation of the imine.

Preferred first reactants of the present invention, such as compounds of formula (I), are chosen in the group consisting of: furfuryl alcohol, 2,5 furandimethanol, 2,5-tetrahydrofuranedimethanol, benzyl alcohol, 1,6-hexandiol and 1,7- heptandiol.

Second reactant being NH₃ or a reactant having primary amine functionality

This second reactant may notably be a compound of formula (II) : R²-NH₂ (II)

Wherein:

R² is H or a straight, branched or cyclic hydrocarbon group 2 may represent straight, branched or cyclic hydrocarbon group that can be an alkyl, alkenyl, aryl, cycloalkyl or heterocyclic group, eventually comprising one or several heteroatoms such as O, S, F, and N. Preferred groups for R² may be for example : H, alkyl, phenyl, benzyl, cycloalkyl, and cycloalkene. In addition the second reactant may comprise additional functionalities. The additional functionalities may behave as electron donating or electron withdrawing groups as long as their presence does not prevent reaction with the amine to form the imine. There is no particular limitation on the number of carbon atoms present in the reactant as long as its structure does not prevent the formation of the imine.

Preferred second reactants of the present invention, such as compounds of formula (II), are chosen in the group consisting of: ammoniac, phenylamine, n- heptylamine, aniline and methylamine.

Imine

This imine produced by the reaction of first and second reactant may notably be a compound of formula (III) :

R¹-(CH=NR²)x (III)

x is 1 or 2

R¹ is H or a straight, branched or cyclic hydrocarbon group

R² is H or a straight, branched or cyclic hydrocarbon group

Preferred imines of the present invention, such as compounds of formula (III), are chosen in the group consisting of: N-phenylbenzylimine, (tetrahydrofuran- 2,5-diyl)dimethanimine, (furan-2,5-diyl)dimethanimine, l, -(tetrahydrofuran- 2,5-diyl)bis(N-methyliminomethane), 1,6-hexamethylenediimine, and Ι,Γ- (tetrahydrofuran-2,5-diyl)bis(N-heptaneiminomethane). Primary or secondary amine

The primary or secondary amine of the present invention may notably be a compound of formula (IV) :

R¹(CH₂~NHR²)x (IV)

Wherein:

x is 1 or 2

R is H or a straight, branched or cyclic hydrocarbon group

Preferred primary or second amines of the invention, such as compounds of formula (IV), are chosen in the group consisting of : N-phenylbenzylamine, (tetrahydrofuran-2,5-diyI) dimethanamine, (furan-2,5-diyl) dimethanamine, 1,6- hexamethylenediamine, 1 , 1 '-(tetrahydrofuran-2,5-diyl)bis(N- methylmethylamine), and 1 , 1 '-(tetrahydrofuran-2,5-diyl)bis(N- heptaneaminomethane) .

Reactions of the invention

Preferred reactions of the present invention are the following :

Reaction of benzylalcohol (I) and aniline (II) to produce N-phenyl benzylimine (III) and N-phenyl benzylamine (IV)

Reaction of 2,5-tetrahydrofurandimethanol (I) and ammonia (II) to produce (tetrahydrofuran-2,5-diyl)dimethanimine (III) and (tetrahydrofuran-2,5- diyl)dimethanamine (IV).

Reaction of 2,5-furandimethanol (I) with ammoniac (II) to produce (furan-2,5-diyl)dimethanimine (III) and (furan-2,5-diyl)dimethanamine (IV).

Reaction of 1,6-hexandiol (I) with ammoniac (II) to produce 1,6- hexamethylenediimine (III) and 1,6-hexamethylenediamine (IV) Reaction of 2,5-tetrahydrofuranedimethanol (I) with N-heptylamine (II) to produce l, r-(furan-2,5"diyl)bis(N-heptaneiminomethane) (III) and 1,1'- (tetrahydrofuran-2,5-diyl)bis(N-heptaneaminomethane) (IV). Ordered porous manganese-based octahedral molecular sieves

Ordered porous manganese-based octahedral molecular sieves (OMS) constitute an exemplary class of molecular sieves. These materials have one-dimensional tunnel structures and unlike zeolites, which have tetrahedrally coordinated species serving as the basic structural unit, these materials are based on six- coordinate manganese surrounded by an octahedral array of anions (e.g., oxide).

Manganese oxide octahedral molecular sieves (OMS) possessing mono- directional tunnel structures constitute a family of molecular sieves wherein chains of Mn0₆ octahedra share edges to form tunnel structures of varying sizes. Such materials have been identified in samples of terrestrial origin and are also found in manganese nodules recovered from the ocean floor. Manganese nodules have been described as useful catalysts in the oxidation of carbon monoxide, methane and butane (U.S. Pat. No. 3,214,236), the reduction of nitric oxide with ammonia (Atmospheric Environment, Vol. 6, p.309 (1972)) and the demetallation of topped crude in the presence of hydrogen (Ind. Eng. Chem. Proc. Dev. l, Vol. 13, p.315 (1974)).

The OMS framework topology is dictated by the type of arrangement of the MnO_¾ octahedra, such as corner-sharing, edge-sharing, or face-sharing. The ability of manganese to adopt multiple oxidation states and of the Mn0₆ octahedra to adopt different arrangements affords the formation of a large variety of OMS materials. The OMS may further comprise an additional transition metal within the molecular framework as long as the incorporation of the additional transition metal does not collapse the one-dimensional tunnel structure.

In one embodiment, the OMS catalyst comprises todorokites. Todorokites include materials wherein the Mn0₆ octahedra share edges to form triple chains and the triple chains share corners with adjacent triple chains to form a 3x3 tunnel structure. The size of an average dimension of these tunnels is about 6.9 Angstroms (A). A counter cation, for maintaining overall charge neutrality, such as Na, Ca, Mg, and the like is present in the tunnels and is coordinated to the oxides of the triple chains. Todorokites are generally represented by the formula (M)Mn₃0₇, wherein M represents the counter cation and manganese is present in at least one oxidation state. Further, the formula may also include waters of hydration and is generally represented by (M)_yMn₃C>7.xH₂0, where y is about 0.3 to about 0.5 and x is about 3 to about 4.5.

In one embodiment, the OMS catalyst comprises hollandites. Hollandites include a family of materials wherein the Mn0₆ octahedra share edges to form double chains and the double chains share corners with adjacent double chains to form a 2x2 tunnel structure. The size of an average dimension of these tunnels is about 4.6 A. A counter cation for maintaining overall charge neutrality such as Ba, , Na, Pb, and the like, is present in the tunnels and is coordinated to the oxides of the double chains. The identity of the counter cation determines the mineral species or the structure type. Hollandites are generally represented by the formula (M)Mn₈0i₆, wherein M represents the counter cation and manganese is present in at least one oxidation state. Further, the formula may also include waters of hydration and is generally represented by (M)_yMn_gOi₆.xH₂0, where y is about 0.8 to about 1.5 and x is about 3 to about 10. Suitable hollandites include hollandite (BaMn₈0i₆), cryptomelane

manjiroite (NaMn₈0_]6), coronadite (PbMn_sOi₆), and the like, and variants of at least one of the foregoing hollandites. In one embodiment, the OMS catalyst comprises cryptomelane-type materials. In some embodiments some or all of the counter cation is H⁺. In one embodiment, the OMS catalyst has an average Mn oxidation state of about 3 to about 4, Within this range the average oxidation state may be greater than or equal to about 3.2, or, more specifically, greater than or equal to 3.2, or even more specifically, greater than or equal to about 3.3. Average oxidation state may be determined by potentiometric titration.

In an exemplary method the OMS catalyst can be prepared by combining an aqueous solution of KMnO₄ (0.2 to 0.6 molar), an aqueous solution of MnSO₄.¾0 (1.0 to 2.5 molar) and a concentrate acid such as HN0₃. The aqueous solution is refluxed at 100°C for 18-36 hours. The product is filtered, washed and dried, typically at a temperature of 100 to 140°C. Similar procedures are known in the literature, for example, DeGuzman et ah, Chem. Mater. 1994, 6, 815-821.

The OMS may be used in any form that is convenient, such as particulate, aggregate, film or combination thereof. In addition, the OMS may be affixed to a substrate to facilitate separation of the catalyst from the product.

The hydrothermal method of synthesizing a manganese oxide octahedral molecular sieve possessing (2x2) tunnel structures similar to the naturally- occurring hollandites is described in "Hydrothermal Synthesis of Manganese Oxides with Tunnel Structures," in Synthesis of Microporous Materials, Vol, II, 333, M. L. Occelli, H. E. Robson Eds. Van Nostrand Reinhold, N.Y., 1992. Such synthetic octahedral molecular sieves having (2x2) tunnel structures are referred to in the art by the designation OMS-2. The hydrothermal method of producing OMS-2 involves autoclaving an aqueous solution of manganese cation and permanganate anion under acidic conditions, i.e., pH<3, at temperatures ranging from about 80 to about 140°C in the presence of counter cations having ionic diameters of between about 2.3 and about 4.6 A. The counter cations serve as templates for the formation of OMS-2 product and can be retained in the tunnel structures thereof. Based on analytical tests, OMS-2 produced via this method is thermally stable up to about 600°C. Alternatively, OMS-2 can be produced by the method disclosed in R. Giovanili and B. Balmer, Chimia, 35 (1981) 53. Thus, when manganese cation and permanganate anion are reacted under basic conditions, i.e., pH>12, a layered manganese oxide precursor is produced. This precursor is ion exchanged to form another layered manganese oxide which is then calcined at high temperatures, i.e., temperatures generally exceeding about 600°C, to form OMS-2 product. Analytical tests indicate that OMS-2 produced via this method is thermally stable up to about 800°C and the average oxidation state of manganese ion is lower. The temperatures to produce OMS may be reached either thermically or via microwave irradiation.

Transition metal of Group 8 to 11 elements of the Periodic Table

A transition metal according to the present invention is a metal able to provide a reduction on imine, preferably on imine of formula (III), i.e. R -(CH=N )x

The transition metal is preferably chosen from the group consisting of Pd, Pt, Ru, Os, Ir, Ag, Au or a mixture thereof. More preferably the metal transition is a metal from the platinum group metals (PGMs), that are Pd, Pt, Rh, Ru, Ir and Os. The preferable method to prepare ordered porous manganese-based octahedral molecular sieves comprising a transition metal of Group 8 to 11 elements of the Periodic Table is the successive wet impregnation, or the co-precipitation, notably with the potassium permanganate and the magnesium sulfate under acidic conditions.

The activation or re-activation of the modified OMS catalysts may involve a calcination step and/or a reduction step under hydrogen. Notably, the activation of the modified OMS catalysts may involve a calcination step under air 0₂ at 300-500°C for 1-24 hours and a reduction step under hydrogen at the same temperature for 1 -6 hours according to M. Abecassis-Wolfovich et al. Applied Catalysis B: Environmental 2005, 59, 91). The concentration of transition metal on the OMS carrier may be comprised between 0.1 and 20% by weight, preferably from 1 to 10% by weight.

The weight ratio of ordered porous manganese-based octahedral molecular sieves comprising a transition metal of Group 8 to 11 elements of the Periodic Table to the second reactant may be comprised between 0.05 and 2, preferably from 0.1 to 0.5.

Conditions of the reaction

The reaction temperature may be comprised between 80 and 250°C. The reaction may be carried out in liquid or gas phase. In liquid phase, the reaction may be performed in the absence or presence of a solvent. The solvent is typically chosen based on its ability to dissolve the reactants. The solvent may be protic, aprotic or a combination of protic and aprotic solvents. Exemplary solvents include toluene, octane, xylene, benzene, n- butanol, and acetonitrile. In some embodiments the solvent is a non-polar, aprotic solvent such as toluene. Solvents comprising hydroxyl functionalities or amine functionalities may be used as long as the solvent does not participate in the reaction in place of the reactant.

The reactants, with an optional solvent, and the catalyst are typically combined in a reaction vessel and stirred to constitute the reaction mixture. The reaction mixture is typically maintained at the desired reaction temperature under stirring for a time sufficient to form the primary or the secondary amine in the desired quantity and yield.

The reaction may be carried out in the presence of air but preferably with an inert atmosphere such as N₂, Ar, C0₂ or even NH₃. Suitable oxygen containing gases include air, oxygen gas, and mixtures of oxygen gas with other gases such as nitrogen or argon. In some embodiments the oxygen containing gas is a flowing oxygen containing gas. In other embodiments the reaction vessel is charged with the oxygen containing gas.

The progress of the reaction toward the imine and the primary or secondary amine may be followed using an appropriate method such as thin layer chromatography, nuclear magnetic resonance, high-pressure liquid chromatography, gas chromatography or a combination of the foregoing methods. Exemplary reaction times are 1 to 24 hours, preferably 1 to 8 hours.

The catalyst is typically removed from the reaction mixture using any solid/liquid separation technique such as filtration, centrifugation, and the like or a combination of separation methods. The product may be isolated using standard isolation techniques, such as distillation.

In addition, the OMS catalyst can be reused. If desired, the catalyst can be regenerated by washing with methanol, water or a combination of water and methanol and subjecting the washed catalyst to a temperature of about 150°C to about 300°C for about 6 to 24 hours in the presence of oxygen.

The invention is further illustrated by the following non-limiting examples.

EXPERIMENTAL PART

Example 1 : OMS Preparation

The preparation of the OMS catalyst used in the examples is as follows. 680 milliliters (ml) of potassium permanganate solution (40g) was added to a mixture of 173 ml manganese sulfate hydrate solution (54.4g) and 6.8 ml of concentrated nitric acid in a 1000 ml of round bottom flask with a condenser. The dark brown slurry was refluxed for 24 hours at 1 10°C, then filtered and washed with de-ionized water several times. The catalyst was dried at 120°C overnight before use. The composition of the K-OMS-2 catalyst was KMn₈0i₆.nH₂0 and the runnels had dimensions of 4.6x4.6 angstroms. The average oxidation state of the manganese was approximately 3.8. The H-K- OMS-2 catalyst was generated by stirring the K-OMS-2 catalyst in a 1 Molar solution of nitric acid for 6 hours at 60-70°C for 6 hours. The morphological and textural characteristics of the K-OMS-2 catalyst were inspected, respectively, by X-ray diffraction analysis and N₂ isotherm adsorption at 77.4 K. The XRD patterns for the fresh K-OMS-2 sample reveals the presence of a pure cryptomelane phase (KMn8016, JCPDS 29, 1020). The K-OMS-2 catalyst show a high surface area (143 m /g). The N₂ adsorption/desorption isotherm plots for the -OMS-2 catalyst reveal the presence of mesopores in the structure. The mesopore size range is between 17 and 62 nm, indicating a large amount of slit-shaped mesopores with uniform form sizes or shapes. Moreover, a sharp increase of the sorption loading is observed at low P/Po values, pointing out the presence of micropores with a pore size of 0.36 nm.

The thermal stability of the K-OMS-2 material was studied by thermo- gravimetric analysis (TGA) under N₂ atmosphere in the range of 50-100°C with a ramp of 10°C/min. Four characteristic weight loss temperature ranges are observed: (i) 50-200°C (1.2 %wt), which is attributed to physisorbed 0₂ and water; (ii) 350-550°C (3%), which is most likely attributed to chemisorbed oxygen and water; (iii) 550-700°C, involving the release of lattice oxygen from the manganese oxide; and (iv) 700-750°C, which is ascribed to the conversion of manganese Mn(IV) to lower oxidation states.

Example 2: Impregnation

The palladium/K-OMS-2 catalyst was prepared by dry impregnation of lg of K- OMS-2. 7.03 mL of Pd(NH₃)₄(N0₃)₂ [Pd: 1.42 g/L] was added drop wise to the support. The mixture was stirred for 2 hours at 80°C. The slurry was dried in a rota-evaporator first at 80°C for 2 hours and at 120°C overnight. Finally the solid was calcined at 350°C for 2 hours under oxygen.

Example 3: Synthesis of secondary amine / Proportion of catalysts

Benzylalcohol and aniline are used to produce the N-phenyl benzylimine (a) and N-phenyl benzylamine (b) and eventually N-phenyl dibenzylamine (c).

Several proportions of catalysts were used with a molar ratio of aniline/benzyl alcohol = 1/3 in a sealed tube at a pressure of 1 bar, 160°C for 3 hours in an agitated medium (600 rpm) un N₂. After the reaction time the mixture was cooled and the catalyst was removed by filtration. The product mixture was analyzed by gas chromatography-FID [GC- FID]. The results are expressed in Table 1.

Table 1

Another comparative trial was made by using 16 mg of Pd/Fe₂0₃ catalyst rather than the catalyst of the present invention, for 2h at 160 C, under N₂. It leads to a 100 % aniline conversion, 2% selectivity of imine, 94% selectivity of secondary amine and 4% selectivity of tertiary amine.

It appears then that the catalyst of the present invention permits to produce secondary amine with a very high selectivity and a very good conversion of aniline without generating tertiary amine.

Example 4: Synthesis of secondary amine / Time reaction

New trials were made according to Example 3 while using 60 mg Pd 2%/K- OMS-2 for 1, 3 or 6 hours. Results are expressed in Table 2 Table 2

Example 5: Synthesis of secondary amine / Effect of the reaction atmosphere

New trials were made according to Example 3 while using 60 mg Pd 2%/K- OMS-2 for 3 hours under N₂ or 0₂. Results are expressed in Table 3

Table 3

It can be observed that a 100% aniline conversion is obtained under 0₂ or N₂, but the selectivity of secondary amine is 93% under nitrogen atmosphere and decreases to 56% under 0₂. These results are unexpected since OMS is considered as an oxidation catalyst and demonstrate the synergistic effect of the transition metal-OMS combination according to the present invention.

Claims

WHAT IS CLAIMED IS:

1. A process for forming a primary or a secondary amine via a direct amination reaction comprising reacting:

- A first reactant having one or two primary hydroxyl functionalities, with A second reactant being NH₃ or a reactant having primary amine functionality,

in the presence of ordered porous manganese-based octahedral molecular sieves comprising a transition metal of Group 8 to 1 1 elements of the Periodic Table; and at a temperature and for a time sufficient for the primary amine or the secondary amine to be produced.

2. Process according to claim 1 wherein the first reactant is a compound of formula (I) :

Wherein:

x is 1 or 2

R¹ is H or a straight, branched or cyclic hydrocarbon group.

3. Process according to claim 2 wherein R¹ is an alkyl, alkenyl, aryl, cycloalkyl or heterocyclic group, eventually comprising one or several heteroatoms such as O, S, F, and N.

4. Process according to anyone of claims 1 to 3, wherein first reactants are chosen in the group consisting of: furfuryl alcohol, 2,5 furandimethanol, 2,5- tetrahydrofuranedimethanol, benzyl alcohol, 1 ,6-hexandiol and 1,7-heptandiol.

5. Process according to anyone of claims 1 to 4, wherein the second reactant is a compound of formula (II) :

R²-NH₂ (II)

Wherein:

is H or a straight, branched or cyclic hydrocarbon group.

6. Process according to claim 5 wherein R is an alkyl, alkenyl, aryl, cycloalkyl or heterocyclic group, eventually comprising one or several heteroatoms such as O, S, F, and N.

7. Process according to anyone of claims 1 to 6, wherein the second reactants are chosen in the group consisting of: ammoniac, phenylamine, n-heptylamine, aniline and methylamine.

8. Process according to anyone of claims 1 to 7, wherein the primary or second amine is a compound of formula (IV) :

R¹(CH₂-NHR²)x (IV)

Wherein:

x is 1 or 2

R¹ is H or a straight, branched or cyclic hydrocarbon group

R² is H or a straight, branched or cyclic hydrocarbon group.

9. Process according to anyone of claims 1 to 8, wherein the primary or second amines are chosen in the group consisting of : N-phenylbenzylamine, (tetrahydrofuran-2,5-diyl) dimethanamine, (furan-2,5-diyl) dimethanamine, 1 ,6- hexamethylenediamine, 1 , 1 '-(tetrahydrofuran-2,5-diyl)bis(N- methylmethylamine), 1 , 1 '-(tetrahydrofuran-2,5-diyl)bis(N- heptaneaminomethane) .

10. Process according to anyone of claims 1 to 9, wherein the ordered porous manganese-based octahedral molecular sieves comprise todorkites.

1 1. Process according to anyone of claims 1 to 9, wherein the ordered porous manganese-based octahedral molecular sieves comprise hollandites.

12. Process according to anyone of claims 1 to 1 1, wherein the ordered porous manganese-based octahedral molecular sieves have an average manganese oxidation state of about 3 to about 4.

13. Process according to anyone of claims 1 to 11 , wherein the transition metals are chosen from the group consisting of : Pd, Pt, Ru, Os, Ir, Ag, Au or a mixture thereof.

14. Process according to anyone of claims 1 to 13, wherein the ordered porous manganese-based octahedral molecular sieves comprising a transition metal of Group 8 to 1 1 elements of the Periodic Table are prepared by successive wet impregnation or co-precipitation.

15. Process according to anyone of claims 1 to 14, wherein the concentration of transition metal on the ordered porous manganese-based octahedral molecular sieves is comprised between 0.1 and 20% by weight.

16. Process according to anyone of claims 1 to 1 , wherein the weight ratio of ordered porous manganese-based octahedral molecular sieves comprising a transition metal of Group 8 to 1 1 elements of the Periodic Table to the second reactant is comprised between 0.05 and 2.

17. Process according to anyone of claims 1 to 14, wherein the reaction temperature is comprised between 80 and 250°C.

18. Process according to anyone of claims 1 to 17, wherein the reaction is carried out in liquid or gas phase.

19. Process according to anyone of claims 1 to 17, wherein the reaction is performed in the presence of a solvent.

20. Ordered porous manganese-based octahedral molecular sieves comprising a transition metal of Group 8 to 11 elements of the Periodic Table.

21. Composition comprising at least an imine and a primary or a secondary amine, said composition is substantially free or, in some cases, completely free of tertiary amine.