Preparation and application of magnetic metallic oxide cross-linked acidic polyionic liquid

Abstract

The present disclosure discloses the preparation and application of magnetic metallic oxide cross-linked acidic polyionic liquid, belonging to the technical field of solid acid catalysis. The catalyst prepared by the present disclosure has good Lewis acid site and Brnsted acid site, and has the characteristics of high speed, high efficiency, environment friendliness and the like when catalyzing preparation of furfural from xylose. The catalyst has the advantages of easy separation, multiple cycles of recycling and the like, and is green and pollution-free. The magnetic metal oxide cross-linked acidic polyionic liquid prepared by using the present disclosure has the characteristics of high speed, high efficiency, environment friendliness and the like when catalyzing preparation of furfural from xylose, and meanwhile, the catalyst has the advantages of easy separation, multiple cycles of recycling and the like, and is green and pollution-free.

Claims

1. A magnetic metal oxide cross-linked acidic polyionic liquid prepared by a process comprising the following steps: thiolating a metal oxide support, wherein the metal oxide support is -Al.sub.2O.sub.3, ZrO.sub.2, TiO.sub.2 or SnO.sub.2, crosslinking the metal oxide support with divinylimidazole halide under action of an initiator to obtain a metal oxide cross-linked polyionic liquid, wrapping the metal oxide cross-linked polyionic liquid with magnetic nanoparticles to obtain a magnetic metal oxide cross-linked polyionic liquid, and reacting the magnetic metal oxide cross-linked polyionic liquid with concentrated acid to obtain the magnetic metal oxide cross-linked acidic polyionic liquid.

2. The magnetic metal oxide cross-linked acidic polyionic liquid according to claim 1, wherein the metal oxide is Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-Cl, Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-NO.sub.3, Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-H.sub.2PO.sub.3, or Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-HSO.sub.4 wherein IM is divinlyimidazolium cation.

3. The magnetic metal oxide cross-linked acidic polyionic liquid according to claim 1, wherein the thiolation of the metal oxide support comprises: adding the metal oxide support with -mercaptopropyltrimethoxysilane in an organic solvent, reacting in an oil bath under an inert gas, cooling, filtering, washing and drying to obtain a thiolated metal oxide support.

4. The magnetic metal oxide cross-linked acidic polyionic liquid according to claim 1, wherein obtaining the metal oxide cross-linked polyionic liquid comprises: under action of the initiator, reacting the thiolated metal oxide support and the divinylimidazole halide in a methanol solvent in an oil bath under an inert condition, cooling to room temperature, filtering, washing with alcohol, and drying to obtain the metal oxide cross-linked polyionic liquid.

5. The magnetic metal oxide cross-linked acidic polyionic liquid according to claim 1, wherein the concentrated acid is concentrated hydrochloric acid, concentrated nitric acid, concentrated phosphoric acid or concentrated sulfuric acid.

6. The magnetic metal oxide cross-linked acidic polyionic liquid according to claim 1, wherein wrapping the metal oxide cross-linked polyionic liquid comprises: dispersing the nanoparticles and the metal oxide cross-linked polyionic liquid in ethanol, stirring vigorously in a water bath, cooling to room temperature, carrying out magnetic separation, washing with alcohol, and drying to obtain the magnetic metal oxide cross-linked polyionic liquid.

7. The magnetic metal oxide cross-linked acidic polyionic liquid according to claim 1, wherein obtaining the magnetic metal oxide cross-linked acidic polyionic liquid specifically comprises the following steps: dispersing the magnetic metal oxide cross-linked polyionic liquid in deionized water, dropwisely adding concentrated acid under an ice bath condition, stirring at room temperature in a water bath, filtering, washing with water, and drying to obtain the magnetic metal oxide cross-linked acidic polyionic liquid.

8. The magnetic metal oxide cross-linked acidic polyionic liquid according to claim 1, wherein the process specifically comprises: (1) synthesizing divinylimidazole halide; (2) thiolation of the metal oxide support: reacting the metal oxide support with -mercaptopropyltrimethoxysilane in a toluene solvent in an oil bath under an inert condition, cooling to room temperature, filtering, washing with alcohol, and drying to obtain the thiolated metal oxide support; (3) under the action of the initiator, reacting the thiolated metal oxide support and the divinylimidazole halide in a methanol solvent in an oil bath under an inert condition, cooling to room temperature, filtering, washing with alcohol, and drying to obtain the metal oxide cross-linked polyionic liquid; (4) wrapping Fe.sub.3O.sub.4 nanoparticles with metal oxide cross-linked polyionic liquid: dispersing the Fe.sub.3O.sub.4 and the metal oxide cross-linked polyionic liquid in ethanol, stirring vigorously in a water bath, cooling to room temperature, carrying out magnetic separation, washing with alcohol, and drying to obtain the magnetic metal oxide cross-linked polyionic liquid; and (5) obtaining the magnetic metal oxide cross-linked acidic polyionic liquid: dispersing the magnetic metal oxide cross-linked polyionic liquid in deionized water, dropwisely adding concentrated acid under an ice bath condition, stirring at room temperature in a water bath, filtering, washing with water, and drying to obtain the magnetic metal oxide cross-linked acidic polyionic liquid.

9. A method, comprising adding the magnetic metal oxide cross-linked acidic polyionic liquid of claim 1 as a catalyst to a reaction comprising xylose, catalyzing production of furfural from xylose and obtaining furfural from the reaction wherein the metal oxide support is -Al.sub.2O.sub.3, TiO.sub.2 or SnO.sub.2.

10. The method according to claim 9, wherein the xylose and the magnetic metal oxide cross-linked acidic polyionic liquid catalyst are placed into a reactor with the mass ratio of 1:(0.3-0.7), and a reaction solvent is added to react.

11. The method according to claim 10, wherein the reaction solvent is any one or a combination of two or more of DMSO, DMF, DMA, NMP, THF, 2-MTHF, toluene and n-butanol.

12. The method according to claim 11, wherein the addition ratio of the xylose to the reaction solvent is 100 mg: (1-5 mL).

13. The method according to claim 9, wherein the reaction is carried out at 120 C.160 C. for 1-5 h.

14. The method according to claim 13, wherein the reaction is carried out in an oil bath.

15. The method according to claim 9, wherein the method specifically comprises: (1) placing xylose and a magnetic metal oxide cross-linked acidic polyionic liquid catalyst in a reactor with the mass ratio of 1:(0.3-0.7), adding a reaction solvent, reacting at 120 C.160 C. in an oil bath for 1-5 h, and cooling after the reaction is finished; (2) after the reaction solution in step (1) is cooled, diluting a certain amount of reaction solution with deionized water to a specified volume, and determining conversion rate of xylose and yield of furfural by a high-performance liquid chromatograph; and (3) after the reaction in step (1) is finished, separating out the catalyst by action of an external magnetic field, washing with alcohol, and drying the catalyst to be re-added to the reaction system of step (1).

16. A preparation method of the magnetic metal oxide cross-linked acidic polyionic liquid of claim 1, comprising: after thiolation of a metal oxide support, crosslinking with divinylimidazole halide under action of an initiator to obtain a metal oxide cross-linked polyionic liquid, then wrapping magnetic nanoparticles with the metal oxide cross-linked polyionic liquid to obtain a magnetic metal oxide cross-linked polyionic liquid, and reacting the magnetic oxide cross-linked polyionic liquid with concentrated acid to obtain the magnetic metal oxide cross-linked acidic polyionic liquid wherein the metal oxide support is -Al.sub.2O.sub.3, TiO.sub.2 or SnO.sub.2.

17. The magnetic metal oxide cross-linked acidic polyionic liquid according to claim 1, wherein the metal oxide cross-linked acidic polyionic liquid is Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-HSO.sub.4 wherein IM is divinlyimidazolium cation.

Description

BRIEF DESCRIPTION OF FIGURES

(1) FIG. 1 is a synthetic route of divinylimidazolium halide;

(2) FIG. 2 is a preparation route of a thiol-modified metal oxide support;

(3) FIG. 3 is preparation of a magnetic metal oxide support immobilized cross-linked acidic polyionic liquid;

(4) FIG. 4 is a reaction diagram of production of furfural from xylose using the magnetic metal oxide cross-linked acidic polyionic liquid as a catalyst;

(5) FIG. 5 is a graph showing the yield of the solid acid catalyst in Example 7 catalyzing the xylose reaction in different solvents;

(6) FIG. 6 is a graph showing the yield of the solid acid catalyst in Example 8 catalyzing the xylose reaction in different solvent amounts;

(7) FIG. 7 is a graph showing the yield of the solid acid catalyst in Example 9 catalyzing the xylose reaction at different temperatures;

(8) FIG. 8 is a graph showing the yield of the solid acid catalyst in Example 10 catalyzing the xylose reaction at different times; and

(9) FIG. 9 is a graph showing the yield of the solid acid catalyst in Example 11 catalyzing the xylose reaction at different catalyst amounts.

DETAILED DESCRIPTION

(10) The following is a detailed description of the present disclosure.

(11) Conversion Rate of Xylose:

(12) $\mathrm{Xylose}\mathrm{conversion}\left(\mathrm{mol}\%\right)=\left(1-\frac{\mathrm{moles}\mathrm{of}\mathrm{remaining}\mathrm{xylose}}{\mathrm{moles}\mathrm{of}\mathrm{starting}\mathrm{xylose}}\right)100\%$

(13) Yield of Furfural:

(14) $\mathrm{Furfural}\mathrm{yield}\left(\mathrm{mol}\%\right)=\left(\frac{\mathrm{moles}\mathrm{of}\mathrm{furfural}}{\mathrm{moles}\mathrm{of}\mathrm{starting}\mathrm{xylose}}\right)100\%$

Example 1: Synthesis of Divinylimidazole Halide

(15) 1-vinylimidazole and 1,2-dibromoethane, dichloroethane or diiodoethane were weighed, a toluene solvent was added to react in an oil bath, the solid was filtered out and dissolved in methanol, decolorization was carried out by activated carbon, filtration and rotary evaporation were carried out, and drying was carried out to obtain the divinylimidazole halide.

(16) The synthetic route is shown in FIG. 1.

Example 2: Preparation of Magnetic Metal Oxide Cross-Linked Acidic Polyionic Liquid

(17) The preparation route of the magnetic metal oxide cross-linked acidic polyionic liquid is shown in FIGS. 2-3.

(18) (1) Divinylimidazole halide was taken;

(19) (2) thiolation of metal oxide support: the metal oxide support was reacted with -mercaptopropyltrimethoxysilane in a toluene solvent in an oil bath under an inert condition, and after the reaction was cooled to room temperature, filtering and washing with alcohol were carried, and drying was performed to obtain the thiolated metal oxide support;

(20) (3) under the action of the initiator, the thiolated metal oxide support was reacted with the divinylimidazole halide in a methanol solvent in an oil bath under an inert condition, and after the reaction was cooled to room temperature, filtering and washing with alcohol were carried, and drying was carried out to obtain the metal oxide cross-linked polyionic liquid;

(21) (4) wrapping ferroferric oxide nanoparticles with metal oxide cross-linked polyionic liquid: the ferroferric oxide and the metal oxide cross-linked polyionic liquid were dispersed in ethanol, and stirred vigorously in a water bath, and the mixture was cooled to room temperature, magnetically separated, washed with alcohol, and dried to obtain the magnetic metal oxide cross-linked polyionic liquid; and

(22) (5) magnetic metal oxide cross-linked acidic polyionic liquid: the magnetic metal oxide cross-linked polyionic liquid was dispersed in deionized water, concentrated sulfuric acid was dropwisely added under an ice bath condition, and the mixture was stirred at room temperature in a water bath, filtered, washed with water, and dried to obtain the magnetic metal oxide cross-linked acidic polyionic liquid.

(23) The oxide support was Al.sub.2O.sub.3, ZrO.sub.2, TiO.sub.2 or SnO.sub.2, and the obtained magnetic metal oxide cross-linked acidic polyionic liquid was Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-HSO.sub.4, Fe.sub.3O.sub.4@ZrO.sub.2-SH-IM-HSO.sub.4, Fe.sub.3O.sub.4@TiO.sub.2-SH-IM-HSO.sub.4 or Fe.sub.3O.sub.4@SnO.sub.2-SH-IM-HSO.sub.4.

Example 3: Production of Furfural from Xylose Using Magnetic Metal Oxide Cross-Linked Acidic Polyionic Liquid as Catalyst

(24) Similar to the method of Example 2, -Al.sub.2O.sub.3 was selected as the oxide support, and the concentrated sulfuric acid in step (5) was replaced with concentrated hydrochloric acid, concentrated nitric acid or concentrated phosphoric acid to obtain the magnetic metal oxide cross-linked acidic polyionic liquid Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-Cl, Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-NO.sub.3 or Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-H.sub.2PO.sub.3. The properties of the products obtained with different concentrated acids were compared. The method was as follows:

(25) (1) 50 mg of magnetic metal oxide cross-linked acidic polyionic liquid (Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-Cl, Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-NO.sub.3, Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-H.sub.2PO.sub.3 or Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-FHSO.sub.4) was weighed and added to a reactor containing 3 mL of DMSO;

(26) (2) 100 mg of xylose was weighed in the reaction system of step (1), and stirred in an oil bath at 140 C. for 3 h, and the reaction product was taken out and cooled after the reaction was finished; and

(27) (3) after the reaction product was cooled, 50 L of sample was taken and diluted to 5 mL with deionized water, and the yield of furfural was determined by a high-performance liquid chromatograph.

(28) It was determined that under the catalytic action of the Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-Cl, Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-NO.sub.3, Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-H.sub.2PO.sub.3 and Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-FHSO.sub.4, the yield of furfural was respectively 42%, 43%, 55% and 72%.

Example 4: Production of Furfural from Xylose Using Fe.SUB.3.O.SUB.4.@Al.SUB.2.O.SUB.3.-SH-IM-HSO.SUB.4 .as Catalyst

(29) FIG. 4 is a possible reaction diagram of production of furfural from xylose using the magnetic metal oxide cross-linked acidic polyionic liquid as a catalyst.

(30) (1) 50 mg of magnetic metal oxide cross-linked acidic polyionic liquid (Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-HSO.sub.4) was weighed and added into a reactor containing 3 mL of DMSO, toluene or n-butanol;

(31) (2) 100 mg of xylose was weighed in the reaction system of step (1), and stirred in an oil bath at 140 C. for 3 h, and the reaction product was taken out and cooled after the reaction was finished; and

(32) (3) after the reaction product was cooled, 50 L of sample was taken and diluted to 5 mL with deionized water, and the yield of furfural was determined by a high-performance liquid chromatograph.

(33) It was determined that in the DMSO, toluene and n-butanol, the yield of furfural was respectively 72%, 58% and 56%.

Example 5: Production of Furfural from Xylose Using Fe.SUB.3.O.SUB.4.@Al.SUB.2.O.SUB.3.-SH-IM-HSO.SUB.4 .as Catalyst

(34) (1) 30-70 mg of magnetic metal oxide cross-linked acidic polyionic liquid (Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-HSO.sub.4) was weighed and respectively added into a reactor containing 3 mL of DMSO;

(35) (2) 100 mg of xylose was weighed in the reaction system of step (1), and stirred in an oil bath at 140 C. for 3 h, and the reaction was taken out and cooled after the reaction was finished; and

(36) (3) after the reaction product was cooled, 50 L of sample was taken and diluted to 5 mL with deionized water, and the yield of furfural was determined by a high-performance liquid chromatograph.

(37) It was determined that when the amount of the solid acid catalyst was respectively 30, 40, 50, 60 and 70 mg, the yield of furfural was respectively 48%, 63%, 72%, 70% and 65%.

(38) After the reaction of Example 4 was finished, the solid acid catalyst under the optimum conditions was magnetically separated out, cleaned, dried, and added to the optimum experimental conditions in the examples for repeated calculation. It was experimentally calculated that after the solid acid catalyst was recycled 5 times, the yield of furfural was still up to 63%.

Example 7

(39) (1) 50 mg of magnetic metal oxide cross-linked acidic polyionic liquid (Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-HSO.sub.4) was weighed and added into a reactor containing 3 mL of DMSO;

(40) (2) the DMSO in step (1) was replaced with another organic solvent such as DMF, DMA, NMP, THF, 2-MTHF, toluene or n-butanol.

(41) (3) 100 mg of xylose was weighed in the reaction system of step (1) and step (2), and stirred in an oil bath at 140 C. for 3 h, and the reaction product was taken out and cooled after the reaction was finished; and

(42) (4) after the reaction product was cooled, 50 L of sample was taken and diluted to 5 mL with deionized water, and the yield of furfural was determined by a high-performance liquid chromatograph.

(43) After the determination, the results as shown in FIG. 5. In DMSO, DMF, DMA, NMP, THF, 2-MTHF, toluene and n-butanol, the yield of furfural was respectively 72%, 32%, 22%, 21%, 38%, 37%, 58% and 56%.

Example 8

(44) (1) 50 mg of magnetic metal oxide cross-linked acidic polyionic liquid (Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-HSO.sub.4) was weighed and added into reactors respectively containing 1, 2, 3, 4 and 5 mL of DMSO;

(45) (2) 100 mg of xylose was weighed in the reaction system of step (1), and stirred in an oil bath at 140 C. for 3 h, and the reaction product was taken out and cooled after the reaction was finished; and

(46) (3) after the reaction product was cooled, 50 L of sample was taken and diluted to 5 mL with deionized water, and the yield of furfural was determined by a high-performance liquid chromatograph.

(47) After the determination, the results are shown in FIG. 6. When the solvent amount was respectively 1, 2, 3, 4 and 5 mL, the yield of furfural was respectively 46%, 64%, 72%, 55% and 38%.

Example 9

(48) (1) 50 mg of magnetic metal oxide cross-linked acidic polyionic liquid (Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-HSO.sub.4) was weighed and added into a reactor containing 3 mL of DMSO;

(49) (2) 100 mg of xylose was weighed in the reaction system of step (1), and stirred in an oil bath at 110-160 C. for 3 h, and the reaction product was taken out and cooled after the reaction was finished; and

(50) (3) after the reaction product was cooled, 50 L of sample was taken and diluted to 5 mL with deionized water, and the yield of furfural was determined by a high-performance liquid chromatograph.

(51) After the determination, the results are shown in FIG. 7. At a temperature gradient of 120-160 C., the yield of furfural was respectively 41%, 65%, 72%, 63% and 52%.

Example 10

(52) (1) 50 mg of magnetic metal oxide cross-linked acidic polyionic liquid (Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-HSO.sub.4) was weighed and added into a reactor containing 3 mL of DMSO;

(53) (2) 100 mg of xylose was weighed in the reaction system of step (1), and stirred in an oil bath at 140 C. for a temperature gradient of 1-5 h, and the reaction product was taken out and cooled after the reaction was finished; and

(54) (3) after the reaction was cooled, 50 L of sample was taken and diluted to 5 mL with deionized water, and the yield of furfural was determined by a high-performance liquid chromatograph.

(55) After the determination, the results are shown in FIG. 8. When the reaction temperature was respectively 1, 2, 3, 4 and 5 h, the yield of furfural was respectively 38%, 52%, 72%, 65% and 53%.

Example 11

(56) (1) 30, 40, 50, 60 and 70 mg of magnetic metal oxide cross-linked acidic polyionic liquid (Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-HSO.sub.4) were weighed and respectively added into reactors containing 3 mL of DMSO;

(57) (2) 100 mg of xylose was weighed in the reaction system of step (1), and stirred in an oil bath at 140 C. for 3 h, and the reaction product was taken out and cooled after the reaction was finished; and

(58) (3) after the reaction product was cooled, 50 L of sample was taken and diluted to 5 mL with deionized water, and the yield of furfural was determined by a high-performance liquid chromatograph.

(59) After determination, the results are shown in FIG. 9. When the solid acid catalyst amount was respectively 30, 40, 50, 60 and 70 mg, the yield of furfural was respectively 48%, 63%, 72%, 70% and 65%.

(60) After the reaction of Example 5 was finished, the solid acid catalyst under the optimum conditions was magnetically separated out, cleaned, dried, and added to the optimum experimental conditions in the examples for repeated calculation. It was experimentally calculated that after the solid acid catalyst was recycled 5 times, the yield of furfural was still up to 63%.

Example 12: Preparation of Magnetic Metal Oxide Cross-Linked Acidic Polyionic Liquid (Fe.SUB.3.O.SUB.4.@M.SUB.x.O.SUB.y.-SH-IM-HSO.SUB.4.)

(61) The preparation of the magnetic metal oxide cross-linked acidic polyionic liquid was carried out by the following steps:

(62) (1) Synthesis of divinylimidazole halide:1-vinylimidazole and 1,2-haloethane were weighed, a toluene solvent was added to react in an oil bath, the solid was filtered out and dissolved in methanol, decolorization was carried out by activated carbon, filtration and rotary evaporation were carried out, and drying was carried out to obtain the divinylimidazole halide.

(63) (2) Thiolation of metal oxide support: the support was reacted with -mercaptopropyltrimethoxysilane in a toluene solvent in an oil bath under an inert condition, and after the reaction was cooled to room temperature, filtering and washing with alcohol were carried, and drying was carried out to obtain the thiolated metal oxide support.

(64) (3) Under the action of the initiator azodiisobutyronitrile, the thiolated metal oxide support was reacted with the divinylimidazole halide in a methanol solvent in an oil bath under an inert condition, and after the reaction was cooled to room temperature, filtering and washing with alcohol were carried, and drying was carried out to obtain the metal oxide cross-linked polyionic liquid.

(65) (4) Wrapping Fe.sub.3O.sub.4 nanoparticles with metal oxide cross-linked polyionic liquid: the Fe.sub.3O.sub.4 and the metal oxide cross-linked polyionic liquid were dispersed in ethanol and stirred vigorously in a water bath, and the mixture was cooled to room temperature, magnetically separated, washed with alcohol, and dried to obtain the magnetic metal oxide cross-linked polyionic liquid.

(66) (5) Magnetic metal oxide cross-linked acidic polyionic liquid: the magnetic metal oxide cross-linked polyionic liquid was dispersed in deionized water, concentrated sulfuric acid was dropwisely added under an ice bath condition, and the mixture was stirred at room temperature in a water bath, filtered, washed with water, and dried to obtain the magnetic metal oxide cross-linked acidic polyionic liquid.

(67) The metal oxide support in step (2) may be -Al.sub.2O.sub.3, ZrO.sub.2, TiO.sub.2, SnO.sub.2, or the like, and the obtained magnetic metal oxide cross-linked acidic polyionic liquid was respectively Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-HSO.sub.4, Fe.sub.3O.sub.4@ZrO.sub.2-SH-IM-HSO.sub.4, Fe.sub.3O.sub.4@TiO.sub.2-SH-IM-HSO.sub.4 or Fe.sub.3O.sub.4@SnO.sub.2-SH-IM-HSO.sub.4.

Example 13: Comparison of Catalytic Properties of Magnetic Metal Oxide Cross-Linked Acidic Polyionic Liquid Prepared by Different Metal Oxide Supports

(68) The catalytic properties of the magnetic metal oxide cross-linked acidic polyionic liquid prepared by different metal oxide supports were compared as follows:

(69) (1) 50 mg of magnetic metal oxide cross-linked acidic polyionic liquid was respectively weighed and added into a reactor containing 3 mL of DMSO;

(70) (2) 100 mg of xylose was weighed in the reaction system of step (1), and stirred in an oil bath at 140 C. for 3 h, and the reaction product was taken out and cooled after the reaction was finished; and

(71) (3) after the reaction product was cooled, 50 L of sample was taken and diluted to 5 mL with deionized water, and the yield of furfural was determined by a high-performance liquid chromatograph.

(72) After the determination, the results are shown in Table 1.

(73) TABLE-US-00001 TABLE 1 Catalytic properties of different magnetic metal oxide cross-linked acidic polyionic liquids. Yield of Conversion Rate Yield of Furfural After Catalyst of Xylose Furfural Recycling 5 Times Fe.sub.3O.sub.4@Al.sub.2O.sub.3- 97% 72% 63% SH-IM-HSO.sub.4 Fe.sub.3O.sub.4@ZrO.sub.2- 85% 56% 45% SH-IM-HSO.sub.4 Fe.sub.3O.sub.4@TiO.sub.2- 78% 47% 35% SH-IM-HSO.sub.4 Fe.sub.3O.sub.4@SnO.sub.2- 91% 58% 48% SH-IM-HSO.sub.4

Example 14: Production of Furfural from Xylose Using Magnetic Metal Oxide Cross-Linked Acidic Polyionic Liquid as Catalyst

(74) Similar to the method of Example 6, -Al.sub.2O.sub.3 was selected as the oxide support, and the concentrated sulfuric acid in step (5) was replaced with concentrated hydrochloric acid, concentrated nitric acid or concentrated phosphoric acid to obtain the magnetic metal oxide cross-linked acidic polyionic liquid Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-Cl, Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-NO.sub.3 or Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-H.sub.2PO.sub.3. The properties of the products obtained with different concentrated acids were compared. The method was as follows:

(75) (1) 50 mg of magnetic metal oxide cross-linked acidic polyionic liquid (Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-Cl, Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-NO.sub.3, Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-H.sub.2PO.sub.3 or Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-HSO.sub.4) was weighed and added to a reactor containing 3 mL of DMSO;

(76) (2) 100 mg of xylose was weighed in the reaction system of step (1), and stirred in an oil bath at 140 C. for 3 h, and the reaction product was taken out and cooled after the reaction was finished; and

(77) (3) after the reaction product was cooled, 50 L of sample was taken and diluted to 5 mL with deionized water, and the yield of furfural was determined by a high-performance liquid chromatograph.

(78) It was determined that under the catalytic action of the Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-Cl, Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-NO.sub.3, Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-H.sub.2PO.sub.3 and Fe.sub.3O.sub.4@Al.sub.2O.sub.3-SH-IM-FHSO.sub.4, the yield of furfural was respectively 42%, 43%, 55% and 72%.

(79) The above-mentioned examples are better examples of the present disclosure, but are not restrictions on the examples of the present disclosure. In this field, any other changes, modifications, combinations, substitutions and simplifications that do not depart from the principles and spirit of the present disclosure belong to the equivalent replacement mode and are included in the scope of protection of the claims of the present disclosure.