Immobilized metalloporphyrin catalyst and its utilization in maleic acid preparation

Abstract

The present disclosure discloses an immobilized metalloporphyrin catalyst and its utilization in maleic acid preparation, belonging to the technical field of metalloporphyrin catalytic application. The immobilized metalloporphyrin catalyst is used for catalyzing furfural to prepare maleic acid and is good in catalytic effect, mild in reaction conditions and capable of greatly reducing the energy consumption required in the prior art. The catalyst disclosed by the present disclosure can provide a good microenvironment for a reaction, so that the yield and selectivity of maleic acid are increased; and according to a method disclosed by the present disclosure, the conversion ratio of furfural is 20.4%-95.6%, the yield of maleic acid is 10%-56.1%, and the selectivity is 43.6%-76.1%. Meanwhile, the catalyst is easy to separate and environmentally friendly and may be recycled for many times.

Claims

1. A method for preparing maleic acid by catalytically oxidizing furfural, comprising carrying out a reaction of catalytically oxidizing furfural by using an immobilized metalloporphyrin catalyst, wherein furfural serves as a substrate and oxygen serves as an oxidant, and wherein the immobilized metalloporphyrin catalyst is obtained after combining metalloporphyrin with a molecular sieve carrier.

2. The method according to claim 1, wherein the molecular sieve carrier is selected from a group consisting of MCM-41, SBA-15, ZSM-5, and a combination thereof.

3. The method according to claim 1, wherein structural formula of the metalloporphyrin is ##STR00003## where R comprises-H, Br, Cl, F, CH3, OCH3 and COOCH3; and M represents for a metal element Fe, Mn, Co, Cu, Zn or Ni.

4. The method according to claim 1, wherein the metalloporphyrin is substituted tetraphenylporphyrin iron.

5. The method according to claim 1, wherein reaction temperature of catalytic oxidation is 70-120 C., reaction time is 3-12 h, and applied reaction pressure is 0.2-1.2 MPa.

6. The method according to claim 1, wherein mass ratio of the catalyst to the substrate is 1:15 to 1:3.

7. The method according to claim 1, further comprising separating the catalyst by filtration after ending the reaction of catalytically oxidizing furfural, carrying out cleaning and drying, and then, reusing the catalyst for the reaction of catalytically oxidizing furfural.

Description

BRIEF DESCRIPTION OF FIGURES

(1) FIG. 1 is a reaction route for preparing maleic acid in the present disclosure;

(2) FIG. 2 is a yield diagram of furfural reactions catalyzed by using metalloporphyrin catalysts with different carrier types in Embodiment 1;

(3) FIG. 3 is a yield diagram of furfural reactions catalyzed by using an immobilized metalloporphyrin catalyst at different temperatures in Example 2;

(4) FIG. 4 is a yield diagram of furfural reactions catalyzed by using the immobilized metalloporphyrin catalyst at different times in Example 3;

(5) FIG. 5 is a yield diagram of furfural reactions catalyzed by using different usage amounts of immobilized metalloporphyrin catalyst in Example 4;

(6) FIG. 6 is a yield diagram of furfural reactions catalyzed by using the immobilized metalloporphyrin catalyst at different reaction pressures in Example 5.

DETAILED DESCRIPTION

(7) The present disclosure is further described below in conjunction with examples, however, the examples of the present disclosure are not limited herein.

(8) $\mathrm{Selectivity}=\frac{\mathrm{Yield}}{\mathrm{Conversion}}100\%$$\mathrm{Conversion}=\frac{\mathrm{Moles}\mathrm{of}\mathrm{furfural}\mathrm{converted}}{\mathrm{Moles}\mathrm{of}\mathrm{furfural}\mathrm{used}}100\%$$\mathrm{Yield}=\frac{\mathrm{Moles}\mathrm{of}\mathrm{maleic}\mathrm{acid}\mathrm{formed}}{\mathrm{Moles}\mathrm{of}\mathrm{furfural}\mathrm{used}}100\%$

Example 1

(9) (1) 50 mg of immobilized metalloporphyrin catalyst FeT(p-R)PP/SBA-15 (wherein R is Br) is weighed and placed into a polytetrafluoroethylene liner, and the immobilized metalloporphyrin catalyst and the polytetrafluoroethylene liner are added into 4 mL of deionized water;

(10) (2) the carrier SBA-15 in step (1) is replaced with MCM-41 and ZSM-5;

(11) (3) 0.282 g of furfural is weighed and added into reaction systems in steps (1) and (2), the polytetrafluoroethylene liner is placed into a stainless steel reactor, heating is carried out to reach 90 C. under magnetic stirring, oxygen is introduced, 1 MPa reaction pressure is applied to carry out a reaction for 6 h, an oxygen cylinder valve is closed after the reaction is ended, the reactor is cooled to the room temperature, and then, a gas in the reactor is slowly released; and

(12) (4) 50 L of reaction solution in step (3) is transferred by using a pipette, the volume is metered to 5 mL by using deionized water, and the yield of maleic acid is measured by using a high-performance liquid chromatograph.

(13) By measurement, results are shown in FIG. 2, maleic acid has the yield of 38%, 27.8% or 22.3% and the selectivity of 70.8%, 67.6% or 67% respectively when furfural is catalytically oxidized by using the catalyst prepared by taking SBA-15, MCM-41 or ZSM-5 as a carrier.

(14) The catalytic effect is compared with the immobilized Ferriporphyrin catalysts with different substituent groups including H, Br, Cl, F, CH.sub.3, OCH.sub.3, COOCH.sub.3 and SO.sub.3Na. It is showed that the catalytic effect is best when the substituent group is Br, and the detail is shown in the experimental data Table 1.

(15) TABLE-US-00001 TABLE 1 Results for Preparing Maleic Acid by Catalytically Oxidizing Furfural by Using Immobilized Ferriporphyrins with Different Substituent Groups. Group Catalyst Selectivity (%) 1 FeTPP/SBA-15 48.7 2 FeT(p-Br)PP/SBA-15 70.8 3 FeT(p-Cl)PP/SBA-15 63.5 4 FeT(p-F)PP/SBA-15 52.3 5 FeT(p-CH.sub.3)PP/SBA-15 62.4 6 FeT(p-OCH.sub.3)PP/SBA-15 63 7 FeT(p-COOCH.sub.3)PP/SBA-15 65.1 8 FeT(p-SO.sub.3Na)PP/SBA-15 56.2 Note: Reaction conditions: furfural, 0.282 g; catalyst, 50 mg; H.sub.2O, 4 mL; 90 C.; 6 h; and O.sub.2, 1 MPa.

(16) In addition, the disclosure tries to coordinate six metals including iron, manganese, cobalt, copper, zinc and nickel with the porphyrin ligand for a catalytic reaction, and the detail is shown in the experimental data Table 2.

(17) TABLE-US-00002 TABLE 2 Experimental Results for Preparing Maleic Acid by Catalytically Oxidizing Furfural by Using Immobilized Porphyrins with Different Kinds of Metals. Conversion Yield Selectivity Group Catalyst (%) (%) (%) 1 FeT(p-Br)PP/SBA-15 53.7 38 70.8 2 MnT(p-Br)PP/SBA-15 20.5 1.1 5.4 3 CoT(p-Br)PP/SBA-15 33.7 6.2 18.4 4 CuT(p-Br)PP/SBA-15 22 3.6 16.4 5 ZnT(p-Br)PP/SBA-15 38.2 13.6 35.6 6 NiT(p-Br)PP/SBA-15 19.4 0.8 4.1 Note: Reaction conditions: furfural, 0.282 g; catalyst, 50 mg; H.sub.2O, 4 mL; 90 C.; 6 h; and O.sub.2, 1 MPa.

(18) In addition, the catalytic activities of three immobilized metalloporphyrin catalysts with highest conversion ratios under a non-immobilization condition were studied, and the three immobilized metalloporphyrin catalysts are respectively FeT(p-Br)PP with the conversion ratio of 51.2%, ZnT(p-Br)PP with the conversion ratio of 37.5% and CoT(p-Br)PP with the conversion ratio of 30.2%. The catalytic activities of the three immobilized metalloporphyrin catalysts are slightly lower than those under an immobilization condition because mobilized metalloporphyrin has a certain catalytic activity, but the catalyst is relatively poor in stability, and is easy to oxidize and degrade; moreover, when the mobilized metalloporphyrin is in use, the reaction system is a homogeneous system, the catalyst cannot be recycled, and meanwhile, the difficulties of separating and purifying a product are also increased. However, a immobilized catalyst may be repeatedly used, and the performance of the catalyst is reduced by about 2% after the catalyst is recycled for five times.

Example 2

(19) (1) 50 mg of immobilized metalloporphyrin catalyst FeT(p-R)PP/SBA-15 (wherein R is Br) is weighed and placed into a polytetrafluoroethylene liner and is added into 4 mL of deionized water;

(20) (2) 0.282 g of furfural is weighed and added into a reaction system in step (1), the polytetrafluoroethylene liner is placed into a stainless steel reactor, heating is carried out to reach 70-120 C. under magnetic stirring, oxygen is introduced, 1 MPa reaction pressure is applied to carry out a reaction for 6 h, an oxygen cylinder valve is closed after the reaction is ended, the reactor is cooled to the room temperature, and then, a gas in the reactor is slowly released; and

(21) (3) 50 L of reaction solution in step (2) is transferred by using a pipette, the volume is metered to 5 mL by using deionized water, and the yield of maleic acid is measured by using a high-performance liquid chromatograph.

(22) By measurement, results are shown in FIG. 3, maleic acid has the yield of 9.8%, 23.1%, 38%, 48.3%, 37.1% or 35.3% and the selectivity of 48%, 60.5%, 70.8%, 76.1%, 50.1% or 43.6% respectively when the reaction temperature is 70 C., 80 C., 90 C., 100 C., 110 C. or 120 C.

Example 3

(23) (1) 50 mg of immobilized metalloporphyrin catalyst FeT(p-R)PP/SBA-15 (wherein R is Br) is weighed and placed into a polytetrafluoroethylene liner and is added into 4 mL of deionized water;

(24) (2) 0.282 g of furfural is weighed and added into a reaction system in step (1), the polytetrafluoroethylene liner is placed into a stainless steel reactor, heating is carried out to reach 100 C. under magnetic stirring, oxygen is introduced, 1 MPa reaction pressure is applied to carry out a reaction for 3-8 h, an oxygen cylinder valve is closed after the reaction is ended, the reactor is cooled to the room temperature, and then, a gas in the reactor is slowly released; and

(25) (3) 50 L of reaction solution in step (2) is transferred by using a pipette, the volume is metered to 5 mL by using deionized water, and the yield of maleic acid is measured by using a high-performance liquid chromatograph.

(26) By measurement, results are shown in FIG. 4, maleic acid has the yield of 35.7%, 41.6%, 44.1%, 48.3%, 45% or 40.3% and the selectivity of 76.4%, 78%, 79.5%, 76.1%, 65.7% or 49% respectively when the reaction time is 3 h, 4 h, 5 h, 6 h, 7 h or 8 h.

Example 4

(27) (1) 30 mg, 40 mg, 50 mg, 60 mg, 70 mg and 80 mg of immobilized metalloporphyrin catalyst FeT(p-R)PP/SBA-15 (wherein R is Br) are weighed and placed into a polytetrafluoroethylene liner and are added into 4 mL of deionized water;

(28) (2) 0.282 g of furfural is weighed and added into a reaction system in step (1), the polytetrafluoroethylene liner is placed into a stainless steel reactor, heating is carried out to reach 100 C. under magnetic stirring, oxygen is introduced, 1 MPa reaction pressure is applied to carry out a reaction for 6 h, an oxygen cylinder valve is closed after the reaction is ended, the reactor is cooled to the room temperature, and then, a gas in the reactor is slowly released; and

(29) (3) 50 L of reaction solution in step (2) is transferred by using a pipette, the volume is metered to 5 mL by using deionized water, and the yield of maleic acid is measured by using a high-performance liquid chromatograph.

(30) By measurement, results are shown in FIG. 5, maleic acid has the yield of 25.2%, 37.6%, 48.3%, 56.1%, 50.3% or 45.7% and the selectivity of 45.8%, 64.2%, 76.1%, 73.8%, 69.9% or 62% respectively when the usage amount of the catalyst is 30 mg, 40 mg, 50 mg, 60 mg, 70 mg or 80 mg.

Example 5

(31) (1) 60 mg of immobilized metalloporphyrin catalyst FeT(p-R)PP/SBA-15 (wherein R is Br) is weighed and placed into a polytetrafluoroethylene liner and is added into 4 mL of deionized water;

(32) (2) 0.282 g of furfural is weighed and added into a reaction system in step (1), the polytetrafluoroethylene liner is placed into a stainless steel reactor, heating is carried out to reach 100 C. under magnetic stirring, oxygen is introduced, 0.2 MPa, 0.4 MPa, 0.6 MPa, 0.8 MPa, 1 MPa and 1.2 MPa reaction pressures are applied to carry out a reaction for 6 h, an oxygen cylinder valve is closed after the reaction is ended, the reactor is cooled to the room temperature, and then, a gas in the reactor is slowly released; and

(33) (3) 50 L of reaction solution in step (2) is transferred by using a pipette, the volume is metered to 5 mL by using deionized water, and the yield of maleic acid is measured by using a high-performance liquid chromatograph.

(34) By measurement, results are shown in FIG. 6, maleic acid has the yield of 10%, 18.2%, 33%, 45.1%, 56.1% or 55% and the selectivity of 50.1%, 66.9%, 73.4%, 75.5%, 73.8% or 70.7% respectively when the reaction pressure is 0.2 MPa, 0.4 MPa, 0.6 MPa, 0.8 MPa, 1 MPa or 1.2 MPa.

(35) After the reaction in Example 5 is ended, the catalyst under an optimal condition is separated by filtration and is cleaned and dried to be put into the optimal experimental condition in the example so as to be used for repeated calculation. By calculation, immobilized metalloporphyrin is recycled for five times, and the yield of maleic acid still reaches up to 54%.

Example 6: Preparation of Immobilized Metalloporphyrin Catalyst

(36) The immobilized metalloporphyrin catalyst is obtained after substituted tetraphenylporphyrin iron is combined with a molecular sieve carrier; and the method specifically comprises: mixing a certain number of molecular sieve carriers with a DMF solution, carrying out stirring for a period of time by heating until solid particles are uniformly dispersed, slowly and dropwise adding the DMF solution of metalloporphyrin into the mixture, further carrying out a reaction for a period of time, carrying out cooling to the room temperature, carrying out suction filtration, cleaning filter cake by using a solvent until a filtrate is colorless, removing a porphyrin ligand relatively weakly adsorbed on the surfaces of the carriers, and carrying out drying to obtain a brown product.

(37) The preparation of substituted tetraphenylporphyrin iron is performed according to the following steps:

(38) (1) The synthesis of a porphyrin ligand (T(p-R)PP): weighing a certain amount of benzaldehyde with different para-orienting groups, adding propionic acid serving as a solvent, carrying out heating in an oil bath pan until reflowing, then, slowly and dropwise adding a propionic acid solution of pyrrole into the mixed solution, carrying out a reaction for 1 h, carrying out cooling to room temperature, placing the mixed solution into a refrigerator to stand overnight, and carrying out suction filtration to obtain a crude product. The crude product is purified by using a column chromatography, and a dichloromethane/trichloromethane is used as a developing solvent, wherein R includes the substituent groups: H, Br, Cl, F, CH.sub.3, OCH.sub.3 and COOCH.sub.3.

(39) (2) The preparation of substituted tetraphenylporphyrin iron (FeT(p-R)PP): weighing a certain number of porphyrin ligands synthesized in step (1), dissolving the porphyrin ligands into DMF, carrying out heating in an oil bath pan until reflowing, adding FeCl.sub.2.4H.sub.2O into the porphyrin ligands in batches, further carrying out a reaction for a period of time, removing a solvent by using a reduced-pressure distillation method, immersing the obtained solid into deionized water overnight, and carrying out suction filtration and washing until a filtrate is colorless to obtain brown ferriporphyrin.

(40) The molecular sieve carrier is MCM-41, SBA-15 or ZSM-5, and the obtained immobilized metalloporphyrin catalysts are respectively FeT(p-R)PP/MCM-41, FeT(p-R)PP/SBA-15 and FeT(p-R)PP/ZSM-5.

(41) The disclosure described and claimed herein is not to be limited in scope by the specific aspects herein disclosed. Any person skilled in the art can make modifications without departing from the spirit and scope of the disclosure. The scope of protection of the present disclosure should therefore be defined by the claims.