CYCLODEXTRIN-BASED METAL ORGANIC FRAMEWORK MATERIAL AND PREPARATION METHOD THEREFOR

Abstract

The present disclosure belongs to the field of chemical industry production, and particularly relates to CD-MOFs and a preparation method thereof. The preparation method comprises the following steps: (1) formulating a supersaturated γ-cyclodextrin alkaline alcohol aqueous solution containing an alkali metal ion; (2) heating to obtain a hot γ-cyclodextrin solution; and (3) cooling the hot γ-cyclodextrin solution of the step (2), and performing crystallization and separation to obtain the cyclodextrin-based metal organic framework material. The CD-MOFs has perfect crystallization and large specific surface area, which are similar with those of a material prepared by means of traditional methods. The important thing is that the synthesis operation thereof is simple, green, and environmentally friendly, and the time required is shortened from a few hours or even tens of hours to a few minutes, which significantly improves the synthesis efficiency and is conductive to industrial scale production.

Claims

1. A preparation method of CD-MOFs, characterized in that, comprising the following steps of: (1) formulating supersaturated γ-CD alkaline alcohol aqueous solution containing an alkali metal ion; (2) heating to obtain a hot γ-CD solution; and (3) cooling the hot γ-CD solution of the step (2), and performing crystallization and separation to obtain the CD-MOFs.

2. The method according to claim 1, characterized in that, the alkali metal ion is K.sup.+, Rb.sup.+, or Cs.sup.+; and the alcohol is methanol or ethanol.

3. The method according to claim 1, characterized in that, the molar ratio of γ-CD to alkaline-earth metal ion in the supersaturated γ-CD alkaline alcohol aqueous solution is 1:6 to 1:12, the mass volume ratio of γ-CD to water is 0.1:10 to 0.6:10, and the volume ratio of alcohol to water is 2:5 to 5:5.

4. The method according to claim 3, characterized in that, the molar ratio of the γ-CD to metal-salt ion in the supersaturated γ-CD alkaline alcohol aqueous solution is 1:7 to 1:10, the mass volume ratio of γ-CD to water is 0.2:5 to 0.3:5; and the volume ratio of the alcohol to water is 3:5 to 5:5.

5. The method according to claim 4, characterized in that, the pH value of the supersaturated γ-CD alkaline alcohol aqueous solution is 10 to 14, preferably 12 to 14.

6. The method according to claim 4, characterized in that, the temperature of the hot γ-CD solution of the step (2) is 60 to 90° C., preferably 70 to 80° C.

7. The method according to claim 6, characterized in that, the hot γ-CD solution of the step (3) is cooled at a temperature-decreasing rate of 5 to 20° C./min, preferably 7.5 to 15° C./min.

8. The method according to claim 7, characterized in that, the temperature of the hot γ-CD solution is reduced to 5 to 25° C., preferably 10 to 20° C.

9. The method according to claim 1, characterized in that, the separation of the step (3) is processed through centrifugation via a centrifugal machine, or membrane filtration via a membrane with pore diameter less than 500 nm.

10. CD-MOFs prepared by the method according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG. 1 is the x-ray diffraction spectrum of CD-MOFs prepared in Example 1.

[0026] FIG. 2 is the N.sub.2 adsorption-desorption isothermal curve of CD-MOFs prepared in Example 1.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] Hereinafter, the present invention will be further described in details with reference to the examples, but the embodiments are not limited thereto.

[0028] Materials used in the following examples can be commercially available.

Example 1

[0029] (1) 0.35 g (0.27 mmol) of γ-CD and 0.224 g (2.02 mmol) of potassium hydroxide are weighed and both dissolved in a methanol solution (a mixed solution with 8 mL of methanol and 10 mL of deionized water) to obtain a supersaturated γ-CD solution;

[0030] (2) the supersaturated γ-CD solution of the step (1) is heated to 90° C. to obtain a hot cyclodextrin solution; and

[0031] (3) the hot solution of the step (2) is cooled down to 10° C. at 15° C./min, and the CD-MOFs are obtained via centrifugation at speed of 4000 r/min.

[0032] The time of the CD-MOFs preparation is less than 9 min, which is significantly less than that of traditional method. As shown in FIG. 1, the prepared CD-MOFs presented a monocrystal diffraction pattern on the X-ray diffraction spectrum; and the specific surface area of CD-MOFs is 729.3 m.sup.2/g (FIG. 2), which is between 350 and 1400 m.sup.2/g of the material prepared by traditional methods.

Example 2

[0033] (1) 0.40 g (0.31 mmol) of γ-CD and 0.213 g (1.92 mmol) of potassium hydroxide are weighed and both dissolved in a methanol solution (a mixed solution with 4 mL of methanol and 8 mL of deionized water) to obtain a supersaturated γ-CD solution;

[0034] (2) the supersaturated γ-CD solution of the step (1) is heated to 60° C. to obtain a hot cyclodextrin solution; and

[0035] (3) the hot solution of the step (2) is cooled down to 5° C. at 20° C./min, and the CD-MOFs are obtained via centrifugation at speed of 4000 r/min in a centrifuge.

[0036] The time of the CD-MOFs preparation is less than 6 min, which is significantly less than that of traditional method. The prepared CD-MOFs presented a monocrystal diffraction pattern on the X-ray diffraction spectrum; and the specific surface area of CD-MOFs is 568.2 m.sup.2/g, which is between 350 and 1400 m.sup.2/g of the material prepared by traditional methods.

Example 3

[0037] (1) 0.35 g (0.27 mmol) of γ-CD and 0.15 g (2.68 mmol) of cesium hydroxide are weighed and both dissolved in an ethanol solution (a mixed solution with 6 mL of ethanol and 6 mL of deionized water) to obtain a supersaturated γ-CD solution;

[0038] (2) the supersaturated γ-CD solution of the step (1) is heated to 75° C. to obtain a hot cyclodextrin solution; and

[0039] (3) the hot solution of the step (2) is cooled down to 5° C. at 10° C./min, and the CD-MOFs obtained by crystallizing is filtered through a filtration membrane with a pore diameter of 450 nm.

[0040] The time of the CD-MOFs preparation is less than 10 min, which is significantly less than that of traditional method. The prepared CD-MOFs present a monocrystal diffraction pattern on the X-ray diffraction spectrum; and the specific surface area of CD-MOFs is 860.9 m.sup.2/g, which is between 350 and 1400 m.sup.2/g of the material prepared by traditional methods.

Example 4

[0041] (1) 0.40 g (0.31 mmol) of γ-CD and 0.26 g (2.11 mmol) of rubidium hydroxide are weighed and both dissolved in a methanol solution (a mixed solution with 6 mL of methanol and 8 mL of deionized water) to obtain a supersaturated γ-CD solution;

[0042] (2) the supersaturated γ-CD solution of the step (1) is heated to 70° C. to obtain a hot cyclodextrin solution; and

[0043] (3) the hot solution of the step (2) is cooled down to 10° C. at 15° C./min, and CD-MOFs obtained by centrifugation at speed of 4000 r/min.

[0044] The time of the CD-MOFs preparation is less than 7 min, which is significantly less than that of traditional method. The prepared CD-MOFs present a monocrystal diffraction pattern on the X-ray diffraction spectrum; and the specific surface area of CD-MOFs is 1186.7 m.sup.2/g, which is between 350 and 1400 m.sup.2/g of the material prepared by traditional methods.

Example 5

[0045] (1) 0.40 g (0.31 mmol) of γ-CD and 0.27 g (2.64 mmol) of rubidium hydroxide are weighed and both dissolved in an ethanol solution (a mixed solution with 16 mL of ethanol and 40 mL of deionized water) to obtain a supersaturated γ-CD solution;

[0046] (2) the supersaturated γ-CD solution of the step (1) is heated to 60° C. to obtain a hot cyclodextrin solution; and

[0047] (3) the hot solution of the step (2) is cooled down to 5° C. at 5° C./min, and the CD-MOFs obtained by centrifugation at speed of 4000 r/min.

[0048] The time of the CD-MOFs preparation is less than 14 min, which is significantly less than that of traditional method. The prepared CD-MOFs present a monocrystal diffraction pattern on the X-ray diffraction spectrum; and the specific surface area of CD-MOFs is 527.6 m.sup.2/g, which is between 350 and 1400 m.sup.2/g of the material prepared by traditional methods.

Example 6

[0049] (1) 0.40 g (0.31 mmol) of γ-CD and 0.378 g (3.70 mmol) of rubidium hydroxide are weighed and both dissolved in an ethanol solution (a mixed solution with 6 mL of ethanol and 7 mL of deionized water) to obtain a supersaturated γ-CD solution;

[0050] (2) the supersaturated γ-CD solution of the step (1) is heated to 90° C. to obtain a hot cyclodextrin solution; and

[0051] (3) the hot solution of the step (2) is cooled down to 25° C. at 20° C./min, and the CD-MOFs obtained by centrifugation at speed of 4000 r/min

[0052] The time of the CD-MOFs preparation is less than 7 min, which is significantly less than that of traditional method. The prepared CD-MOFs present a monocrystal diffraction pattern on the X-ray diffraction spectrum; and the specific surface area of CD-MOFs is 608.9 m.sup.2/g, which is between 350 and 1400 m.sup.2/g of the material prepared by traditional methods.

Example 7

[0053] (1) 0.40 g (0.31 mmol) of γ-CD and 0.246 g (2.22 mmol) of potassium hydroxide are weighed and both dissolved in a methanol solution (a mixed solution with 8 mL of methanol and 10 mL of deionized water) to obtain a supersaturated γ-CD solution;

[0054] (2) the supersaturated γ-CD solution of the step (1) is heated to 80° C. to obtain a hot cyclodextrin solution; and

[0055] (3) the hot solution of the step (2) is cooled down to 20° C. at a cooling rate of 15° C./min, and the CD-MOFs obtained by crystallizing are filtered through a filtration membrane with a pore diameter of 450 nm.

[0056] The time of the CD-MOFs preparation is less than 7 min, which is significantly less than that of traditional method. The prepared CD-MOFs present a monocrystal diffraction pattern on the X-ray diffraction spectrum; and the specific surface area of CD-MOFs is 1075.8 m.sup.2/g, which is between 350 and 1400 m.sup.2/g of the material prepared by traditional methods.

Example 8

[0057] (1) 0.35 g (0.27 mmol) of γ-CD and 0.15 g (2.68 mmol) of cesium hydroxide are weighed and both dissolved in an ethanol solution (a mixed solution with 6 mL of ethanol and 6 mL of deionized water) to obtain a supersaturated γ-CD solution;

[0058] (2) the supersaturated γ-CD solution of the step (1) is heated to 80° C. to obtain a hot cyclodextrin solution; and

[0059] (3) the hot solution of the step (2) is cooled down to 10° C. at 7.5° C./min, and the CD-MOFs obtained by crystallizing are filtered through a filtration membrane with a pore diameter of 400 nm.

[0060] The time of the CD-MOFs preparation is less than 13 min, which is significantly less than that of traditional method. The prepared CD-MOFs present a monocrystal diffraction pattern on the X-ray diffraction spectrum; and the specific surface area of CD-MOFs is 1018.6 m.sup.2/g, which is between 350 and 1400 m.sup.2/g of the material prepared by traditional methods.

[0061] The above examples are the preferred embodiments of the present invention, but not limited by the above-mentioned examples. Any other changes, modifications, substitutions, combinations, simplifications without departing from the spirit and principle of the present invention shall all be equivalent substitute modes, and fall within the scope of the present invention protection.