Use of dendrimer-based catalysts for reductive amination

Abstract

The present disclosure provides for a method of producing an amine from an alcohol that includes supplying a heterogeneous supported metal catalyst, where the heterogeneous supported metal catalyst comprises nanoparticles of an alloy encapsulated with a dendrimer on a solid support, where the alloy is of Formula I: where Pd is palladium; x is an integer of 20 to 30; y is an integer of 10 to 20, and M is selected from the group consisting of nickel (Ni), cobalt (Co), ruthenium (Ru) and rhodium (Rh), with the caveat that when y is 10, M is not Ni; mixing the heterogeneous supported metal catalyst with a first reagent containing an alcohol moiety and a second reagent containing an amine moiety to form a mixture; and heating the mixture to a predetermined temperature for a predetermined time to produce an amine compound.

Description

[0001]DENDRIMER-BASED CATALYSTS FOR REDUCTIVE AMINATION Technical Field The present disclosure relates generally to catalysts and more particularly to dendrimer- based catalysts for the reductive amination. Background Reductive amination can be used to form primary and secondary amines from alcohols and ammonia or amines, respectively, in the presence of hydrogen. Such amines find extensive applications in various industries including pharmaceuticals, agrochemicals, and materials science. One of the key advantages of the above reductive amination lies in its ability to access primary and secondary amines directly from readily available starting materials, such as alcohols and ammonia or amines. This feature simplifies synthetic routes and can reduce the number of synthetic steps required, thereby enhancing overall efficiency and minimizing waste. Additionally, reductive amination offers flexibility in substrate choice, allowing for reaction conditions to accommodate a wide range of functional groups and structural motifs. There are, however, issues with the above reactions. For example, selectively forming amines by reductive amination (alcohol to amine) over transamination (coupling of two amines) is challenging. One reason is because the reductive amination process typically requires elevated pressures to force the equilibrium towards the desired product. In addition to the desired product, the high pressure and reactions conditions allow for undesirable transamination products to be produced. Developing a catalyst with higher selectivity towards the reductive amination products would result in either lower waste to undesired products and / or less expensive operations to produce the same material. In other words, a catalyst that can exhibit higher selectivity would be valuable for producing amines industrially, but achieving such a catalyst is a known problem. Therefore, there is a need in the art for the discovery of new catalyst families with differentiated properties that are also capable of higher selectivity towards the amination products. Summary The present disclosure addresses the above issues by providing a method for producing an amine from an alcohol using a heterogeneous, supported metal catalyst produced by a process involving a dendrimer intermediate. The present disclosure addresses the challenge of synthesizing and using dendrimer-based catalysts for reductive amination. Such an approach is in contrast to the more typical approach of attempting to address the catalyst synthesis for performing reductive amination. Embodiments of the present disclosure provide for a process that uses a metal catalyst produced by a dendrimer intermediate to achieve nanoparticles of a specified composition supported on a heterogeneous support. A reagent containing an alcohol group is mixed with the desired amine, which can be contained on the same substrate, the catalyst and potentially a solvent. The mixture is heated, optionally in the presence of hydrogen, which causes the desired reaction. For the various embodiments, the present disclosure provides for a method of producing an amine from an alcohol that includes supplying a heterogeneous supported metal catalyst, where the heterogeneous supported metal catalyst comprises nanoparticles of an alloy encapsulated with a dendrimer on a solid support, where the alloy is of Formula I: PdxMy(I)where Pd is palladium; x is an integer of 20 to 30; y is an integer of 10 to 20, and M is selected from the group consisting of nickel (Ni), cobalt (Co), ruthenium (Ru) and rhodium (Rh), with the caveat that when y is 10, M is not Ni; mixing the heterogeneous supported metal catalyst with a first reagent containing an alcohol moiety and a second reagent containing an amine moiety to form a mixture; and heating the mixture to a predetermined temperature for a predetermined time to produce an amine compound. For the various embodiments, the heterogeneous supported metal catalyst can be selected from the group consisting of Pd20Ni20 / G4OH / MCF-17, Pd30Co10 / G4OH / MCF-17, Pd30Ru10 / G4OH / MCF-17, Pd20Rh20 / G4OH / MCF-17, Pd20Ni20@G4OH / SBA-15 and combinations thereof. For the various embodiments, the predetermined temperature can be in a range of 100 to 200oC. For the various embodiments, the predetermined time can be in a range of 1 to 48 hours. For the various embodiments, the dendrimer can be selected from the group consisting of G4OH, G2OH, polyamidoamine (PAMAM), PEGylated, glycodendrimer and combinations thereof. For the various embodiments, the solid support can be selected from the group consisting of MCF- 17, SBA-15, MCM-41, mesoporous carbon, aluminosilicate, Kieselgukr, silicone oxide, alumina, titanium dioxide, magnesium oxide, active carbon and combinations thereof. For the various embodiments, the first reagent containing the alcohol moiety can be selected from the group consisting of benzyl alcohol, 2-(2-aminoethoxy)ethanol and combinations thereof. For the various embodiments, the second reagent containing the amine moiety can be selected from the group consisting of benzyl amine, 2-(2-aminoethoxy)ethanol and combinations thereof. For the various embodiments, the mixture can include 1 to 10 mole percent of the heterogeneous supported metal catalyst. For the various embodiments, the mixture can further include at least one solvent selected from the group consisting of toluene, diglyme, water and combinations thereof. For the various embodiments, heating the mixture to the predetermined temperature for the predetermined time can be in the presence of hydrogen to produce the amine compound. For the various embodiments, the hydrogen is present at a pressure of 0 to 20684 kPa. When heating the mixture in the presence of hydrogen to produce the amine compound the first reagent and the second reagent can, in one embodiment, both be 2-(2-aminoethoxy)ethanol. In one embodiment, when heating the mixture in the presence of hydrogen the heterogeneous supported metal catalyst can be Pd20Ni20@G4OH / SBA-15. Detailed Description The present disclosure provides a method for producing an amine from an alcohol using a heterogeneous, supported metal catalyst produced by a process that involves a dendrimer intermediate. The present disclosure addresses the challenge of synthesizing and using dendrimer-based catalysts for reductive amination. Such an approach is in contrast to the more typical approach of attempting to address the catalyst synthesis for performing reductive amination. Embodiments of the present disclosure provide for a process that uses a metal catalyst produced by a dendrimer intermediate to achieve nanoparticles of a specified composition supported the heterogeneous support, which in the present disclosure are the branched structure of the dendrimer. A reagent containing an alcohol group is mixed with the desired amine, which can be contained on the same substrate, the catalyst and potentially a solvent. The mixture is heated, optionally in the presence of hydrogen, which causes the desired reaction. For the various embodiments, the present disclosure provides for a method of producing an amine from an alcohol that includes supplying a heterogeneous supported metal catalyst, where the heterogeneous supported metal catalyst comprises nanoparticles of an alloy encapsulated with a dendrimer on a solid support, where the alloy is of Formula I:PdxMy(I)where Pd is palladium; x is an integer of 20 to 30; y is an integer of 10 to 20 and M is selected from the group consisting of nickel (Ni), cobalt (Co), ruthenium (Ru) and rhodium (Rh), with the caveat that when y is 10, M is not Ni; mixing the heterogeneous supported metal catalyst with a first reagent containing an alcohol moiety and a second reagent containing an amine moiety to form a mixture; and heating the mixture to a predetermined temperature for a predetermined time to produce an amine compound. For the various embodiments, y + x can equal 40. For the various embodiments, the alloy of Formula I can preferably have any of the following structures: when x and y are 20, M is either Ni or Rh; and when x is 30 and y is 10, M is Co or Ru. Other alloys of Formula I are possible. For the various embodiments, the dendrimer can be selected from the group consisting of G4OH, G2OH, polyamidoamine (PAMAM), PEGylated, glycodendrimer and combinations thereof. Preferably, the dendrimer can be selected from the group consisting of G4OH, G2OH and combinations thereof. Preferably, the dendrimer is G4OH. The dendrimers provided herein can be obtained commercially, for example, PAMAM dendrimers (e.g., G2OH and G4OH) can be obtained from Dendritech Inc. (USA). For the various embodiments, the solid support can be selected from the group consisting of MCF-17 , SBA-15, MCM-41, mesoporous carbon, aluminosilicate, Kieselgukr, silicone oxide, alumina, titanium dioxide, magnesium oxide, active carbon and combinations thereof. The solid support can also be selected from other metal oxide supports, such as ZrO2, ZnO and combinations thereof. Preferably, the solid support can be selected from the group consisting of MCF-17, SBA-15 and combinations thereof. For the various embodiments, forming the heterogeneous supported metal catalyst can include those found in (1) "Metal Nanoparticles Catalyzed Selective Carbon-Carbon Bond Activation in the Liquid Phase” Rong Ye et al., J. Am. Chem. Soc. 2016, 138, 27, 8533-8537; and (2) “Dendrimer-Stabilized Metal Nanoparticles as Efficient Catalysts for Reversible Dehydrogenation / Hydrogenation of N-Heterocycles" Chrisophe Deraedt et al., J. Am. Chem. Soc. 2017, 139, 49, 18084-18092, both of which are incorporated herein by reference in their entity. Specific procedures for forming MCF-17 and SBA-15 are found in the Examples section, below, and are incorporated herein by reference in their entirety. The following is a general description of these procedures. All of the following reactions are carried out at room temperature unless otherwise noted. In producing the heterogeneous supported metal catalysts of the present disclosure the following is a general procedure. The solid support SBA-15 can be synthesized following the standard literature protocol found in, for example, “Triblock Copolymer Syntheses of Mesoporous Silica with Periodic 50 to 300 Angstrom Pores” Dongyuan Zhao, Science 1998, 279, 5350, 548-552. With respect to the formation of SBA-15, for example, poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (Pluronic P123) can be diluted in deionized water, which is then mixed with water and an acid (e.g., HCl) to form a surfactant solution. To this surfactant solution a silica-based support can be added, where examples of such silica-based supports include, but are not limited to, tetraethylorthosilicate. The resulting mixture can be aged at a temperature in the range of 80 to 110 °C for 8 to 28 hours. The solid support, in this case SBA-15, is then recovered by filtration and washed with ethanol and deionized water. The support is dried at 100 °C then calcined at 450- 600 °C for at least 4 h. In another example, the MCF-17 support is synthesized following the standard literature protocol found in “Spherical Siliceous Mesocellular Foam Particles for High-Speed Size Exclusion Chromatography” Yu Han et al. Chem. Mater. 2007, 19, 92292-2298, which is incorporated herein by reference in its entirety. Briefly, MCF-17 is synthesized by dissolving Pluronic P123 in an acidic solution of aqueous HCl to which 1,3,5-trimethylbenzene is added and the solution heated to about 40 °C for 2 h while mixing. After the heating step, tetraethoxysilane (TEOS) is added and stirred for 5 minutes. The solution is heated (e.g., 40 °C) for 20 hours. NH4F is then added and the mixture aged at 100 °C for 24 h, which results in a precipitate that is washed with water and ethanol, and then dried. The resulting solid is calcined in air at 900 °C for 6 h prior to its use. The formation of the solid support MCM-41 can be synthesized in a similar fashion as are known in the art. Generally this synthesis involves a silica source such as tetraethyl orthosilicate and a surfactant that acts as a templating agent like cetyltrimethylammonium bromide. The liquid mixture is calcined leaving behind a mesoporous silica structure. For the various embodiments, the heterogeneous supported metal catalyst of the present disclosure can be formed according to the methods provided in the Examples section, below, which are incorporated herein by reference in their entirety. Generally, the heterogeneous supported metal catalyst can be synthesized following the following general procedure detailed in documents (1) and / or (2) listed above. In forming the heterogeneous supported metal catalyst, a colloidal metal solution is first formed as follows. A stock solution of the dendrimer is formed from the dendrimer and a diluent, such as water at room temperature and pressure. Metal salt precursor of each metal moieties “M “ and Pd (e.g. a chloride salts of Pd and the “M” metal) of the alloy of Formula I are added to the stock solution of the dendrimer at metal molar equivalents equal to the subscripts specified in the catalyst designation. As an example, for a 6 mL of G4OH stock solution containing 1.5 mmol of G4OH the Pd20Rh20catalyst can be made by adding 30 mmol of K2PdCl4 in an aqueous solution and 30 mmol of RhCl3 in an aqueous solution. The headspace over this mixture is flushed with an inert gas (e.g., argon) and the mixture is allowed to sit for 15 to 24 hours (e.g., 18 h). Following this, the mixture is stirred vigorously and a reducing / stabilizing compound, such as NaBH4, is added to the mixture in forming the nanoparticles. For example, for the above example 20 equivalents of 0.5 M NaBH4 relative to the total metal amount can be chilled to 0 °C and added dropwise into the mixture with additional stirring, after which the resulting mixture is subject to dialysis using 12,000 molecular weight cutoff dialysis bags with dionized water changed multiple times (e.g., 4 times) over a 24 hour interval to form the colloidal metal solution. For the various embodiments, the colloidal metal solution is then used to form the heterogeneous supported metal catalyst as follows. The solid support material (e.g., SBA-15 or MCF-17) is added to the aqueous metal mixture at room temperature and sonicated for 3 h. The resulting heterogeneous supported metal catalyst comprising nanoparticles of the alloy encapsulated with the dendrimer on the solid support is recovered by centrifugation, decanting, and drying of the solid overnight at 80 °C. For the various embodiments, the heterogeneous supported metal catalyst can be selected from the group consisting of Pd20Ni20 / G4OH / MCF-17, Pd30Co10 / G4OH / MCF-17, Pd30Ru10 / G4OH / MCF-17, Pd20Rh20 / G4OH / MCF-17, Pd20Ni20@G4OH / SBA-15 and combinations thereof. For the various embodiments, the method of producing the amine from an alcohol includes supplying the heterogeneous supported metal catalyst, as provided herein, and mixing the heterogeneous supported metal catalyst with a first reagent containing an alcohol moiety and a second reagent containing an amine moiety to form a mixture; and heating the mixture to a predetermined temperature for a predetermined time to produce an amine compound. For the various embodiments, the first reagent containing the alcohol moiety can be selected from the group consisting of benzyl alcohol, 2-(2-aminoethoxy)ethanol and combinations thereof. Preferably, the first reagent containing the alcohol moiety is selected from the group consisting of benzyl alcohol, 2-(2-aminoethoxy)ethanol and combinations thereof. For the various embodiments, the second reagent containing the amine moiety can be selected from the group consisting of benzyl amine, 2-(2-aminoethoxy)ethanol and combinations thereof. Preferably, the second reagent containing the amine moiety is selected from the group consisting of benzyl amine, 2-(2-aminoethoxy)ethanol and combinations thereof. For the various embodiments, the mixture can include 1 to 10 mole percent of the heterogeneous supported metal catalyst, based on the total moles of the mixture. For the various embodiments, the mixture also includes a molar ratio of the alcohol moiety from the first reagent to the amine moiety from the second reagent in a range of 0.1:10 to 10:0.1 (moles of alcohol moiety from first reagent : moles of amine moiety from second reagent). Preferably, the mixture also includes a molar ratio of the alcohol moiety from the first reagent to the amine moiety of the second reagent in a range of 1:5 to 5:1 (moles of alcohol moiety from first reagent : moles of amine moiety from second reagent). For the various embodiments, the mixture can further optionally include at least one solvent selected from the group consisting of toluene, diglyme, water and combinations thereof. When present, the amount of solvent used in the mixture can be from greater than 0 (e.g., 1) to 90 wt.% of the mixture based on the total weight of the mixture. Each of the above reactions can take place under stirring with heating to the temperatures provided herein in a reactor, such as a stir-tank reactor, formed of, for example, a non-reactive material such as glass or stainless steel. Both the mixing of the heterogeneous supported metal catalyst with the first reagent containing the alcohol moiety and the second reagent containing the amine moiety to form a mixture, and the heating of the mixture to the predetermined temperature for the predetermined time to produce the amine compound can take place under an inert atmosphere, such as nitrogen, at atmospheric pressure. For the various embodiments, heating the mixture to the predetermined temperature for the predetermined time can be in the presence of hydrogen to produce the amine compound. For the various embodiments, the hydrogen is present at a pressure of 0 to 20684 kPa, as measured at room temperature. Preferably, the hydrogen is present at a pressure of 0 to 6895 kPa, as measured at room temperature. Most preferably, the hydrogen is present at a pressure of 1400 to 1800 kPa, as measured at room temperature. In one embodiment, when heating the mixture in the presence of hydrogen to produce the amine compound the first reagent and the second reagent can both be 2-(2-aminoethoxy)ethanol. For the various embodiments, the 2-(2- aminoethoxy)ethanol can be dissolved in an aqueous ammonia and triglycol dimethyl ether (triglyme) within the amounts provided above for both the amine moiety (coming from the ammonia)and the solvent (up to 90 wt.% triglyme). When heating the mixture in the presence of hydrogen the heterogeneous supported metal catalyst can preferably be Pd20Ni20@G4OH / SBA- 15. For the various embodiments, the predetermined temperature for the heating to produce the amine compound can be in a range of 100 to 200oC. Preferably, the predetermined temperature can be in a range of 160 to 200oC. More preferably, the predetermined temperature is 180oC. For the various embodiments, the predetermined time can be in a range of 1 to 48 hours. Preferably, the predetermined time can be in a range of 12 to 36 hours. More preferably, the predetermined time is 24 hours. Examples Components purchased from commercial vendors are noted herein and used as received unless otherwise noted. All percentages are weight percentages (wt.%) based on the total weight of the mixture used to form the Example (EX) or Comparative Example (CE), unless otherwise noted. The procedure for producing the heterogeneous supported metal catalysts as provided herein are found in two publications: (1) "Metal Nanoparticles Catalyzed Selective Carbon- Carbon Bond Activation in the Liquid Phase” Rong Ye et al., J. Am. Chem. Soc. 2016, 138, 27, 8533-8537. (2) “Dendrimer-Stabilized Metal Nanoparticles as Efficient Catalysts for Reversible Dehydrogenation / Hydrogenation of N-Heterocycles" Chrisophe Deraedt et al., J. Am. Chem. Soc. 2017, 139, 49, 18084-18092. For the following EX and CE, the heterogeneous supported metal catalyst were produced as follows: The SBA-15 support was synthesized following the standard literature protocol (“Triblock Copolymer Syntheses of Mesoporous Silica with Periodic 50 to 300 Angstrom Pores” Dongyuan Zhao, Science 1998, 279, 5350, 548-552). As an example, Pluronic P123 was diluted in deionized water with water at a concentration of 12 wt.% to form a solution that was mixed with 3.5 equivalents by weight of 2 M HCl at 35 °C for 1 h to make a surfactant solution. Tetraethylorthosilicate (TEOS) was added dropwise up to a total concentration of 5 wt.% TEOS in the surfactant solution. The mixture was aged for 24 h at 100 °C in an oven. The product SBA-15 solid support was recovered by filtration and washed with ethanol and deionized water. The support was dried at 100 °C then calcined at 550 °C for at least 5 h. The MCF-17 support was synthesized following the standard literature protocol (“Spherical Siliceous Mesocellular Foam Particles for High-Speed Size Exlusion Chromatography” Yu Han et al. Chem. Mater. 2007, 19, 92292-2298). Briefly, the MCF-17 material was synthesized by dissolving Pluronic P123 in an acidic solution of aqueous HCl (6.5:1 vol:vol water to 37 wt.% aqueous HCl) at a concentration of 5 wt.% P123. 1,3,5- trimethylbenzene was then added to a concentration of 5 wt.% and the solution heated to about 40 °C for 2 h while mixing. After the heating step, tetraethoxysilane (TEOS) was added to bring the total concentration of TEOS to 10 wt.% and stirred for 5 minutes. The solution was heated at 40 °C for 20 h in an autoclave. Lastly, 490 parts per million by weight (ppmw) of NH4F was added and the mixture aged at 100 °C for 24 h. The precipitate was filtered, washed with water and ethanol, and then dried. The resulting solid was calcined in air at 900 °C for 6 h. Other than the MCF-17 and SBA-15 support materials, all other materials were obtained from commercial sources. The fourth-generation polyamidoamine (PAMAM) dendrimer with – OH terminal groups (G4OH) was purchased from Dendritech Inc. as a 9.75 wt.% water solution and diluted to a stock solution at 250 mM by adding water. Each catalyst was synthesized following the following general procedure detailed in the above literature. First, 6 mL of the G4OH stock solution was diluted in 52 mL of water in a flask. Metal precursors (chloride salts of the specified metal) were then added to this stock solution at metal molar equivalents equal to the subscripts specified in the catalyst designation. As an example, the 6 mL of G4OH stock solution contained 1.5 mmol of G4OH so the Pd20Rh20 catalyst was made by adding 30 mmol of K2PdCl4 in an aqueous solution and 30 mmol of RhCl3 in an aqueous solution. The aqueous metal precursor solutions were at 0.01 M metal concentration. The headspace was flushed with argon and the mixture was allowed to sit for 18 h. Following this, the flask was stirred vigorously and 20 equivalents of 0.5 M NaBH4 relative to the total metal amount was chilled to 0 °C and added dropwise into the flask. The final mixture was stirred for an additional 2 h. Lastly, the mixture was subject to dialysis using 12,000 molecular weight cutoff dialysis bags with 2 L of dionized water. This was done over 24 h while changing the dialysis water 4 times. The colloidal metal solution was then used to create the solid catalyst. The specified support material (SBA-15 or MCF-17) was added to the aqueous metal mixture at room temperature and sonicated for 3 h. The solid supported catalyst was recovered by centrifugation, decanting, and drying of the solid overnight at 80 °C. Table 1 provides a list of the heterogeneous supported metal catalysts produced using the above described procedures. Example Reactions with the Heterogeneous Supported Metal Catalyst Reagents and their amounts for the following reaction for each of EX and CE in Table 1 are as follows. steel reactor with a Parr Series 4590 micro stirred reactor, where the electrical heating and stirrer controller was a Parr 4848 reactor controller. In a glove box, 106 mg of 1 and 108 mg 2 were dissolved in 9 mL of toluene in Next 100 mg of the specified catalyst was added and the reactor sealed. The reactor was removed from the glove box and connected to the reactor stand. The reactor was initially at atmospheric pressure with nitrogen and room temperature. The impeller was turned on and electrical heating applied to the reactor body to raise the temperature to 130 °C. The reactor was left mixing at temperature for 24 hours then allowed to cool back to room temperature. Once cooled, the reactor was again transferred into the glove box and the contents recovered for GC analysis (Shimadzu GC-2014 GC using an Agilent DB-5MS column, 30 m, 0.32 mm ID, 1.0 um film, and an FID detector with an 8oC / min temperature ramp between 60oC and 300oC). Table 1 shows the results of catalysts tested for the above reaction. Species 3 in the above reaction is preferred as the reductive amination product. Preferred catalysts had increased selectivity to 3, as seen in Table 1. Table 1 - Results Catalyst 3 Yield 4 Yield Selectivity of 3 vs 3+4 In another set of experiments, 0.15 mL of 2-(2-aminoethoxy)ethanol was dissolved in 2 mL of 30 wt.% aqueous ammonia and 5.5 mL of triglyme in same reactor described above. Again, 100 mg of the specified catalyst was added and the reactor was sealed. The reactor was connected to a high pressure hydrogen supply and the headspace padded then purged several times to evacuate all air and replace with hydrogen. Finally, the pressure was brought to 16 bar hydrogen while at room temperature prior to sealing the reactor. The impeller was started and electric heating applied to the reactor body to bring the temperature to 170 °C. The reactor was allowed to mix at temperature for 24 h at pressure. Following the 24 h period, the reactor was allowed to cool, then once at room temperature, the pressure was slowly vented down. The reactor product was then recovered for GC analysis using the same process described above. Table 2 shows the results of select catalyst on a reaction of interest involving ammonia and targeting either the diamine (not observed) or morpholine (measured at levels shown in Table 2): Table 2 Cat. Time(h) Conv. Morpholine Result Table 2 provides three examples using a more challenging substrate targeting the formation of morpholine. It distinguishes that even some of the favorable catalysts from Table 1 (Pd30Co10, EX 2) are challenged by this reaction. CE P shows that this catalyst does not convert the starting material after 3 hours. If it is allowed to react longer (CE O), it does convert material, but to undesired side products (not recovered / analyzed). The most preferred catalyst (Pd20Ni20, EX 1 in Table 1) does not perform as well as EX 2 in reductive amination (making compound 3, above) on a rate basis as only yields 15.5 % versus 20 % for the same reaction time. It is the most selective catalyst seen in Table 1 and in Table 2 it is seen that it does produce the desired morpholine product at a low, but measurable rate.

Claims

What is Claimed is:

1. A method of producing an amine from an alcohol, comprising: supplying a heterogeneous supported metal catalyst, wherein the heterogeneous supported metal catalyst comprises nanoparticles of an alloy encapsulated with a dendrimer on a solid support, wherein the alloy is of Formula I: PdxMy(I)wherein Pd is palladium; x is an integer of 20 to 30; y is an integer of 10 to 20, and M is selected from the group consisting of nickel (Ni), cobalt (Co), ruthenium (Ru) and rhodium (Rh), with the caveat that when y is 10, M is not Ni; mixing the heterogeneous supported metal catalyst with a first reagent containing an alcohol moiety and a second reagent containing an amine moiety to form a mixture; and heating the mixture to a predetermined temperature for a predetermined time to produce an amine compound.

2. The method of claim 1, wherein the dendrimer is selected from the group consisting of G4OH, G2OH, polyamidoamine (PAMAM), PEGylated, glycodendrimer and combinations thereof.

3. The method of any one of claims 1-2, wherein the solid support is selected from the group consisting of MCF-17, SBA-15, MCM-41, mesoporous carbon, aluminosilicate, Kieselgukr, silicone oxide, alumina, titanium dioxide, magnesium oxide, active carbon and combinations thereof.

4. The method of any one of claims 1-3, wherein the first reagent containing the alcohol moiety is selected from the group consisting of benzyl alcohol, 2-(2-aminoethoxy)ethanol and combinations thereof.

5. The method of any one of claims 1-4, wherein the second reagent containing the amine moiety is selected from the group consisting of benzyl amine, 2-(2-aminoethoxy)ethanol and combinations thereof.

6. The method of any one of claims 1-5, wherein heating the mixture is in the presence of hydrogen to produce the amine compound.

7. The method of claim 6, wherein the first reagent and the second reagent are both 2-(2- aminoethoxy)ethanol.

8. The method of any one of claims 6-7, wherein the hydrogen is present at a pressure of 0 to 20684 kPa.

9. The method of any one of claims 6-8, wherein the heterogeneous supported metal catalyst is Pd20Ni20@G4OH / SBA-15.

10. The method of any one of claims 1-9, wherein the mixture includes 1 to 10 mole percent of the heterogeneous supported metal catalyst based on the total moles of the mixture.

11. The method of any one of claims 1-10, wherein the mixture further includes at least one solvent selected from the group consisting of toluene, diglyme, water and combinations thereof.

12. The method of any one of claims 1-11, wherein the predetermined temperature is in a range of 100 to 200oC.

13. The method of any one of claims 1-12, wherein the predetermined time is in a range of 1 to 48 hours.

14. The method of any one of claims 1-13, wherein the heterogeneous supported metal catalyst is selected from the group consisting of Pd20Ni20 / G4OH / MCF-17,Pd30Co10 / G4OH / MCF-17, Pd30Ru10 / G4OH / MCF-17, Pd20Rh20 / G4OH / MCF-17, Pd20Ni20@G4OH / SBA-15 and combinations thereof.

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