Tri-metallic organic framework (MOF) complex as a reduction catalyst

A tri-metallic organic framework having the formula BixCoyNi(1−x−y)(BTC)(4,4′-bipy), its synthesis, and its use as a reduction catalyst.

BACKGROUND

The present disclosure relates to a tri-metallic organic framework (MOF) complex having the formula: BixCoyNi(1-x-y)(BTC)(4,4′-bipy), its synthesis, and its use as a reduction catalyst.

2. Description of the Related Art

About several million tons of dyes are synthesized yearly. About 15% of them are discharged as wastes in open waters including rivers and seas during dye production and dying processing. There have been several reports on the photodegradation of methyl orange MO by nanomaterials. However, the photodegradation process can be long and costly.

Thus, there is an urgent need to treat wastewater and convert dye wastes from industry effluents like methyl orange to useful chemicals.

SUMMARY

The present subject matter relates to a preparation of a new metallic organic framework (MOF) materials and use thereof in the catalytic reduction of methyl orange (MO) dye. This represents a simple and low-cost technique compared to photodegradation.

The trimetallic organic framework catalysts can be prepared with and without porous carbon (PC) support. The metals used in the trimetallic organic framework can be Co, Ni, Bi, and the ligands can be 4,4′ bipyridine (bpy) and 1,3,5 benzene tricarboxylic acid (BTC) in an appropriate ratio of mmol. The complexes can be prepared in a solvothermal steel apparatus. The starting materials can be metal salts and ligands which are mixed and heated at high temperature for several days for a MOF complex (1)=BixCoyNi(1-x-y)(BTC)(4,4′-bipy) and for supported MOF complex (1@PC)=BixCoyNi(1-x-y)(BTC)(4,4′-bipy)-PC.

The advantage of using a porous carbon support (PC) is that it gives extra stability to an anchored MOF complex hindering and delaying the breakage of its coordination bonds during the catalytic reactions. Thus, the number of catalytic cycles of reduction of methyl orange into dimethyl phenyl diamine and sulfanilic acid derivative components increased from a total of 41.3 cycles for WJ 37=complex (1) to 58.8 cycles for WJ 37-PC=complex (1@PC) with turnover number=0.1260 mmol MO/mg catalyst for (1) and =0.1796 mmol MO/mg catalyst for (1@PC). The total time of the experiments was 205 min for (1) and 380 min for (1@PC).

In an embodiment, the present subject matter relates to a tri-metallic organic framework (MOF) complex comprising: cobalt; nickel; bismuth; 4,4′ bipyridine ligands; and 1,3,5 benzene tricarboxylic acid ligands. The cobalt, nickel, and bismuth may be in an about 0.3:0.3:0.3 molar ratio.

In another embodiment, the present subject matter relates to a tri-metallic organic framework (MOF) complex having the formula: BixCoyNi(1-x-y)(BTC)(4,4′-bipy); wherein x=0.3 and y=0.3; wherein BTC is 1,3,5 benzene tricarboxylic acid bismuth; and 4,4′-bipy is 4,4′-bipyridine. The embodiment may further comprise porous carbon.

In one more embodiment, the present subject matter relates to a method of making a tri-metallic organic framework (MOF) complex having the formula BixCoyNi(1-x-y)(BTC)(4,4′-bipy), the method comprising: adding dimethylformamide (DMF), ethanol, and water to benzene tricarboxylic acid (BTC) and 4,4′-bipyridine (4,4′-bpy) to obtain a first reaction mixture; sonicating the first reaction mixture; adding Co(Cl2·6H2O), NiCl2·6H2O, and Bi(NO3)3·5H2O to the first reaction mixture to obtain a second reaction mixture; sonicating the second reaction mixture until the Co(Cl2·6H2O), NiCl2·6H2O, and Bi(NO3)3·5H2O are dissolved; heating the second reaction mixture; cooling, filtering, washing, and drying a precipitate; and obtaining the BixCoyNi(1-x-y)(BTC)(4,4′-bipy) tri-metallic organic framework (MOF) complex.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Definitions

It will be understood by those skilled in the art with respect to any chemical group containing one or more substituents that such groups are not intended to introduce any substitution or substitution patterns that are sterically impractical and/or physically non-feasible.

“Subject” as used herein refers to any animal classified as a mammal, including humans, domestic and farm animals, and zoo, sports, and pet companion animals such as household pets and other domesticated animals such as, but not limited to, cattle, sheep, ferrets, swine, horses, poultry, rabbits, goats, dogs, cats and the like.

“Patient” as used herein refers to a subject in need of treatment of a condition, disorder, or disease, such as cancer.

The present subject matter relates to a preparation of a new metallic organic framework (MOF) materials and use thereof in the catalytic reduction of methyl orange (MO) dye. This represents a simple and low-cost technique compared to photodegradation.

The trimetallic organic framework catalysts can be prepared with and without porous carbon (PC) support. The metals used in the trimetallic organic framework can be Co, Ni, Bi, and the ligands can be 4,4′ bipyridine (bpy) and 1,3,5 benzene tricarboxylic acid (BTC) in an appropriate ratio of mmol. The complexes can be prepared in a solvothermal steel apparatus. The starting materials can be metal salts and ligands which are mixed and heated at high temperature for several days for a MOF complex (1)=BixCoyNi(1-x-y)(BTC)(4,4′-bipy) and for supported MOF complex (1@PC)=BixCoyNi(1-x-y)(BTC)(4,4′-bipy)-PC.

The advantage of using a porous carbon support (PC) is that it gives extra stability to an anchored MOF complex hindering and delaying the breakage of its coordination bonds during the catalytic reactions. Thus, the number of catalytic cycles of reduction of methyl orange into dimethyl phenyl diamine and sulfanilic acid derivative components increased from a total of 41.3 cycles for WJ 37=complex (1) to 58.8 cycles for WJ 37-PC=complex (1@PC) with turnover number=0.1260 mmol MO/mg catalyst for (1) and =0.1796 mmol MO/mg catalyst for (1@PC). The total time of the experiments was 205 min for (1) and 380 min for (1@PC).

In an embodiment, the present subject matter relates to a tri-metallic organic framework (MOF) complex comprising: cobalt; nickel; bismuth; 4,4′ bipyridine ligands; and 1,3,5 benzene tricarboxylic acid ligands.

In certain embodiments of the MOF complex, the cobalt, nickel, and bismuth may be present in an about 0.3:0.3:0.3 molar ratio.

In another embodiment, the MOF complex may be a complex.

In still another embodiment, the complex may further include porous carbon (PC).

The present subject matter further relates to a method of removing dye from water, such as wastewater, comprising adding an effective amount of the tri-metallic organic framework (MOF) as described herein to water. The method may also include adding NaBH4to the water. An effective amount of the MOF may be about 1 mg per about 41.3 mg of a dye. Removing the about 41.3 mg of the dye may take about 205 minutes.

In an embodiment, the present subject matter relates to a tri-metallic organic framework (MOF) complex having the formula BixCoyNi(1-x-y)(BTC)(4,4′-bipy); where x=0.3 and y=0.3, BTC is 1,3,5 benzene tricarboxylic acid, and 4,4′-bipy is 4,4′-bipyridine.

In some embodiments, the complex may be a catalyst. In various embodiments, the complex may further include porous carbon.

The present subject matter further relates to a method of removing dye from water, such as wastewater, comprising adding an effective amount of the tri-metallic organic framework (MOF) to water. The method may also include adding NaBH4to the water. An effective amount of the MOF may be about 1 mg per about 41.3 mg of a dye. Removing the about 41.3 mg of the dye may take about 205 minutes.

In one more embodiment, the present subject matter relates to a method of making the tri-metallic organic framework (MOF) complex having the formula BixCoyNi(1-x-y)(BTC)(4,4′-bipy), the method comprising: adding dimethylformamide (DMF), ethanol and water to benzene tricarboxylic acid (BTC) and 4,4′-bipyridine (4,4′-bpy) to obtain a first reaction mixture; sonicating the first reaction mixture; adding Co(Cl2·6H2O), NiCl2·6H2O, and Bi(NO3)3·5H2O to the first reaction mixture to obtain a second reaction mixture; sonicating the second reaction mixture until the Co(Cl2·6H2O), NiCl2·6H2O, and Bi(NO3)3·5H2O are dissolved; heating the second reaction mixture; cooling, filtering, washing, and drying a precipitate; and obtaining the BixCoyNi(1-x-y)(BTC)(4,4′-bipy) tri-metallic organic framework (MOF) complex.

In an embodiment of the present production methods, the benzene tricarboxylic acid (BTC) and 4,4′-bipyridine (4,4′-bpy) may be added in an about 1:1 molar ratio.

In another embodiment of the present production methods, the heating can be at a temperature of about 150° C., or from about 145° C. to about 155° C.

In a further embodiment of the present production methods, the second reaction mixture may be heated for about 24 hours.

In an embodiment of the present production methods, the precipitate may be cooled to room temperature. The precipitate can be washed with water and ethanol. The precipitate may be dried in an oven at about 80° C.

In an additional embodiment of the present production methods, the method may further comprise adding the Co(Cl2·6H2O), NiCl2·6H2O, and Bi(NO3)3·5H2O to porous carbon.

The following examples relate to various methods of manufacturing the specific compounds and application of the same, as described herein. All compound numbers expressed herein are with reference to the synthetic pathway figures shown above.

EXAMPLES

In a flask containing 10 mL DMF, 1 mL ethanol and 1 mL water were added to benzene tricarboxylic acid (BTC)(0.1 gm, 0.48 mmole) and 4,4′-bipyridine (4,4′-bpy) (0.075 gm, 0.48 mmole) and dissolved by sonication. Then metals were added to the first mixture on the ligands as followed with continuous sonication to dissolved them: Co(Cl2·6H2O)(0.171 gr, 0.72 mmole), NiCl2·6H2O (0.171 gr, 0.72 mmole) and Bi(NO3)3·5H2O (0.349 gr, 0.72 mmole). Finally the mixture was transferred to an autoclave at 150° C. for 24 hours. After that a precipitate was cooled to room temperature, filtered, washed with water and ethanol, and dried in oven at 80° C. The yield was 0.66 gm.

In flask containing 10 mL H2O porous carbon (0.006 gm 0.5 mmole) was added and dissolved by sonication. Then metals were added to the first mixture on the porous carbon as followed with continued sonication to dissolved them: Co(Cl2·6H2O (0.333 gm, 1.44 mmole), NiCl2·6H2O (0.342 gm, 1.44 mmole), Bi(NO3)3·5H2O (0.698 gm, 1.44 mmole) to obtain a first mixture.

In a separate flask containing 10 mL DMF, BTC (0.1 gm, 0.48 mmole) and 4,4′-bipy (0.075 gm, 0.48 mmole) were added. All was dissolved by sonication. Then the contents of the separate flask were added to the first mixture with continuous sonication. Finally, the mixture was transferred to an autoclave at 170° C. for 48 hours. After that the precipitate was cooled to room temperature, centrifuged, wash with water and ethanol, and dried in an oven at 60° C. for 4 hours. Then the precipitate was dried at room temperature for one day. The yield was 0.67 gm.

Catalytic Study of Complex (1) of Example 1

UV-Vis Spectroscopy Progress of Catalytic Reduction of MO by Complex (1) Catalyst of Example 1

Methyl orange (MO) was chosen as a model organic dye, with NaBH4as a reducing agent. In a typical degradation process, an aqueous suspension of catalysts (1 mg catalyst/1 ml water) was ultrasonically treated. A 0.2 ml of the previous solution, 2.5 ml of distilled water, 0.05 ml of MO in water (32 mg MO/25 ml water) added for each cycle, and 4 mg NaBH4were mixed in a quartz cuvette. The catalytic degradation process of MO was assessed by monitoring the change in intensity of the UV-visible absorption peak of MO at different time. The reduction is considered complete when the absorbance peak at A max 464 nm decreased to almost zero;FIG.3. Examples of catalytic cycles were presented inFIGS.4A,4B,4C, and4D. The kinetics rate first order plot of a selected cycle 50 was presented inFIGS.5A and5B. In conclusion, 0.2 mg of complex (1) achieved 50 cycles and was still in good shape to do more cycles, without the need for regeneration.

Batch (Reactor) Experiment of MO by Catalyst Complex (1) of Example 1

Cyclic catalytic reduction of MO in a flask containing 1 mg of complex (1), 15 mg NaBH4, and 10 ml of water. The addition amount was 1 mg of MO for each cycle. Catalyst (1) was used to treat 41.3 mg of MO in 41.3 cycles at about 205 min without the need of regeneration,FIG.6

The turn over number TON=41.3 mg MO/1 mg catalyst or (0.126 mmole MO/mg catalyst). While the turn over frequency TOF=TON/time=41.3/205 min=0.20146 (mg MO/mg catalyst)/min or (6.15×10−4) (mmole MO/mg catalyst)/min. The data was presented in detail in summary in Table 1 and in detail in Table 2.

Catalytic Study of Complex (1-PC) of Example 2

UV-Vis Spectroscopy Progress of Catalytic Reduction of MO by Complex (1-PC) Catalyst.

The same procedure was followed as above for catalyst (1). The reduction is considered complete when the absorbance peak at λ max 464 nm decreased to almost zero;FIG.7. Examples of catalytic cycles for catalyst (1-PC) were presented inFIGS.8A(cycle 1),8B (cycle 22),8C (cycle 30),8D (cycle 40),8E (cycle 50), and8F (cycle 60). The kinetics rate first order plot of a selected cycle 70 was presented inFIGS.9A and9B. In conclusion, 0.2 mg of complex (1) achieved 70 cycles and still good to do extra more cycles, without the need for regeneration.

Batch (Reactor) Experiment of MO by Catalyst (1-PC)

Cyclic catalytic reduction of MO in a flask containing 1 mg of (1-PC), 20 mg NaBH4, and 10 ml of water. The addition amount was 1 mg of MO for each cycle. Catalyst (1-PC) was used to treat 58.8 mg of MO in 58.8 cycles at about 380 min, without the need for regeneration,FIG.10.

The turn over number TON=58.8 mg MO/1 mg nano=58.8 mg MO/mg nano or (0.1796 mmole MO/mg nano). While the turn over frequency TOF=TON/time=58.8/380 min=0.1547 (mg MO/mg nano)/min or (4.73×10−4) (mmole MO/mg nano)/min. The data was presented in detail in summary in Table 3 and in detail in Table 4.

Finally,FIG.11compared the cycle numbers and duration of experiment by using different Catalyst (1) and (1-PC).

It is to be understood that the 2-(1-(2-hydroxypropyl)-4,5-diphenyl-1H-imidazol-2-yl)pyridine compound, compositions containing the same, and methods of using and producing the same are not limited to the specific embodiments described above, but encompasses any and all embodiments within the scope of the generic language of the following claims enabled by the embodiments described herein, or otherwise shown in the drawings or described above in terms sufficient to enable one of ordinary skill in the art to make and use the claimed subject matter.