Amphiphilic molecular sieve containing hydrophilic group on the outside and lipophilic group on the inside and production method threof

Abstract

The present invention provides an amphiphilic molecular sieve containing a hydrophilic group on the outside and a lipophilic group on the inside and a production method thereof. The production method comprises: dispersing the ZSM-5 spherical nano-molecular sieve into toluene, adding thereto an organosilane containing a hydrophilic group and reacting at 40-80 C. for 2-16 h, to obtain a molecular sieve containing a hydrophilic group; placing the molecular sieve containing a hydrophilic group in an aqueous solution of sodium hydroxide and reacting at 50-90 C. for 10-50 min, to obtain a molecular sieve containing a hydrophilic group on the outside; dispersing the molecular sieve containing a hydrophilic group on the outside into toluene, adding thereto an organosilane containing a lipophilic group and reacting at 40-80 C. for 2-12 h, to obtain the amphiphilic molecular sieve containing a hydrophilic group on the outside and a lipophilic group on the inside. The present invention also provides an amphiphilic molecular sieve obtained by the above production method, which contains a hydrophilic group on the outside and a lipophilic group on the inside.

Claims

1. A method of producing an amphiphilic molecular sieve containing a hydrophilic group on the outside and a lipophilic group on the inside, comprising: a) producing a ZSM-5 spherical nano-molecular sieve with a diameter of 50-200 nm; b) dispersing the ZSM-5 spherical nano-molecular sieve into toluene, adding thereto an organosilane containing a hydrophilic group and reacting at 40-80 C. for 2-16 h, followed by centrifugation, washing and drying, to obtain a molecular sieve containing a hydrophilic group; wherein the amount of substance of the toluene is 40-80 times that of the ZSM-5 spherical nano-molecular sieve, and the amount of substance of the organosilane containing a hydrophilic group is 4-8 times that of the ZSM-5 spherical nano-molecular sieve; c) placing the molecular sieve containing a hydrophilic group in an aqueous solution of sodium hydroxide and reacting at 50-90 C. for 10-50 min, followed by centrifugation, washing and drying, to obtain a molecular sieve containing a hydrophilic group on the outside; and d) dispersing the molecular sieve containing a hydrophilic group on the outside into toluene, adding thereto an organosilane containing a lipophilic group and reacting at 40-80 C. for 2-12 h, followed by centrifugation, washing and drying, to obtain the amphiphilic molecular sieve containing a hydrophilic group on the outside and a lipophilic group on the inside; wherein the amount of substance of the toluene is 40-80 times that of the molecular sieve containing a hydrophilic group on the outside, and the amount of substance of the organosilane containing a lipophilic group is 4-8 times that of the molecular sieve containing a hydrophilic group on the outside.

2. The method according to claim 1, wherein the organosilane containing a hydrophilic group has a structural formula as shown below:
(R.sub.1O).sub.aSiR.sub.4-a or XSiR.sub.4-a wherein R.sub.1 is CH.sub.3, C.sub.2H.sub.5 or H; R is NH.sub.2, COOH, CN or SH; X is halogen; and a is 1, 2 or 3.

3. The method according to claim 1, wherein the organosilane containing a hydrophilic group is 3-aminopropyltriethoxysilane, 2-cyanoethyltriethoxysilane or 3-mercaptopropylmethyltriethoxysilane.

4. The method according to claim 1, wherein in c), the concentration of the aqueous solution of sodium hydroxide is 0.1-4 mol/L.

5. The method according to claim 1, wherein in c), when the concentration of the aqueous solution of sodium hydroxide is less than 0.5 mol/L, and the alkali etching time is less than 30 min, the obtained amphophilic molecular sieve containing a hydrophilic group on the outside and a lipophilic group on the inside has a hollow structure; when the concentration of the aqueous solution of sodium hydroxide is more than 0.5 mol/L, and the alkali etching time is more than 30 min, the obtained amphophilic molecular sieve containing a hydrophilic group on the outside and a lipophilic group on the inside has a half-shell structure.

6. The method according to claim 1, wherein in c), the rotate speed of the centrifugation is 5000-10000 rpm, and the duration of the centrifugation is 5-8 min.

7. The method according to claim 1, wherein in c), the washing is performed 1-2 times with ethanol.

8. The method according to claim 1, wherein in c), the drying is performed at 50-80 C. for 5-12 h.

9. The method according to claim 1, wherein the organosilane containing a lipophilic group has a structural formula as shown below:
(R.sub.1O).sub.bSiR.sub.4-b or YSiR.sub.4-b Wherein R.sub.1 is CH.sub.3, C.sub.2H.sub.5 or H; R is a benzene ring, linear alkane or cycloalkane; Y is halogen; b is 1, 2 or 3.

10. The method according to claim 1, wherein the organosilane containing a lipophilic group is methyltriethoxysilane, cetyltrimethoxysilane, n-octyltrichlorosilane, or cyclohexylmethyldimethoxysilane.

11. The method according to claim 1, wherein in b) and d), the rotate speed of the centrifugation is 5000-10000 rpm, and the duration of the centrifugation is 5-8 min.

12. The method according to claim 1, wherein in b) and d), the washing is washing with toluene followed by washing with trichloromethane.

13. The method according to claim 1, wherein in b) and d), the temperature of the drying is 50-80 C., and the duration of the drying is 5-12 h.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a scanning electron microscope (SEM) image of the amphiphilic molecular sieve containing a hydrophilic group on the outside and a lipophilic group on the inside according to Example 1.

(2) FIG. 2 is a transmission electron microscope (TEM) image of the amphiphilic molecular sieve containing a hydrophilic group on the outside and a lipophilic group on the inside according to Example 1.

(3) FIG. 3 is a wide-angle XRD spectrum of the amphiphilic molecular sieve containing a hydrophilic group on the outside and a lipophilic group on the inside according to Example 1.

(4) FIG. 4 is a SEM image of the precursor sample according to Example 2.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(5) In order to more clearly understand the technical features, objects, and advantages of the present invention, the technical solutions of the present invention will be described in detail below, but it should not be construed as limiting the scope of the present invention.

Example 1

(6) This example provides a production method of an amphiphilic molecular sieve containing a hydrophilic group on the outside and a lipophilic group on the inside, comprising the following steps:

(7) stirring 5 g of tetrapropylammonium hydroxide, 10 g of deionized water, 0.6 g of 1 mol/L sodium hydroxide solution, 0.1 g of aluminum source (aluminum isopropoxide powder), 10 mL of silicon source (ethyl orthosilicate) sufficiently and reacting under hydrothermal conditions for 24 h; centrifuging, washing, drying and sintering to obtain a precursor nano-ZSM-5 molecular sieve material;

(8) dispersing the precursor in 50 mL of toluene, and then adding thereto 1 mL of KH550 organosilane; heating in a water bath at 80 C. for 6 hours, centrifuging and drying, to obtain a molecular sieve containing a hydrophilic group;

(9) adding the molecular sieve containing a hydrophilic group to a 0.5 mol/L NaOH solution, and treating in a water bath at 80 C. for 30 min, washing by centrifugation with water and ethanol at 5000 rpm for 5 min, and drying at 50 C. for 5 h, to obtain a molecular sieve containing a hydrophilic group on the outside;

(10) dispersing the molecular sieve containing a hydrophilic group on the outside in 50 ml of toluene, and then adding thereto 1 mL of cetyltrimethoxysilane; heating in a water bath at 80 C. for 6 hours, and washing the resultant product with trichloromethane and drying, to obtain a half-shell material of molecular sieve containing a hydrophilic group on the outside and a lipophilic group on the inside.

(11) The SEM image of the amphiphilic molecular sieve containing a hydrophilic group on the outside and a lipophilic group on the inside of this example is shown in FIG. 1. As seen from FIG. 1, the finally obtained molecular sieve is a half-shell nanoscale molecular sieve material with a particle size of about 100 nm.

(12) The TEM image is shown in FIG. 2. An obvious half-shell structure can be seen in FIG. 2, and the microporous structure can be clearly seen from the shell wall, which fully demonstrates that the sample maintains the microporous characteristics of the molecular sieve itself intact. This conclusion can also be verified by the wide-angle XRD spectrum of the sample in FIG. 3. The characteristic peaks of the sample in the XRD of the sample completely coincide with those of the MFI-type molecular sieve.

(13) A sample of 0.1 g is placed in a mixed solution of 10 mL of decalin and 10 mL of brine with a concentration of 1 mol/L. After left standing, the sample is in the middle of the solution and has a certain thickness of emulsified layer. This conclusion macroscopically embodies the amphiphilic (hydrophilic and lipophilic) properties of the molecular sieve. The precipitation in the lower part of the water layer can be attributed to the partial damage of the sample during the alkaline etching process.

Example 2

(14) The example provides a production method of a nanoscale molecular sieve pellet, specifically comprising the following steps:

(15) stirring 5 g of tetrapropylammonium hydroxide, 10 g of deionized water, 0.6 g of 1 mol/L sodium hydroxide solution, 0.1 g of aluminum source (aluminum isopropoxide powder), 10 mL of silicon source (ethyl orthosilicate) sufficiently and reacting under hydrothermal conditions for 24 h;

(16) centrifuging, washing, drying and sintering to obtain a nanoscale ZSM-5 molecular sieve.

(17) The nanoscale molecular sieve pellet in this example has a particle size of 100-150 nm and contains a microporous structure, and the SEM image of this molecular sieve is shown in FIG. 4.

Example 3

(18) This example provides an amphiphilic molecular sieve containing a hydrophilic group on the outside and a lipophilic group on the inside obtained by the following steps:

(19) stirring 5 g of tetrapropylammonium hydroxide, 10 g of deionized water, 0.6 g of 1 mol/L sodium hydroxide solution, 0.1 g of aluminum source (aluminum isopropoxide powder), 10 mL of silicon source (ethyl orthosilicate) sufficiently and reacting under hydrothermal conditions for 24 h; centrifuging, washing, drying and sintering to finally obtain a precursor ZSM-5 molecular sieve;

(20) dispersing the precursor in 50 mL of toluene, and then adding thereto 1 mL of KH550 organosilane; heating in a water bath at 80 C. for 6 hours, centrifuging and drying, to obtain a molecular sieve containing a hydrophilic group;

(21) adding the molecular sieve containing a hydrophilic group to a 0.5 mol/L NaOH solution, and treating in a water bath at 65 C. for 20 min, washing by centrifugation with water and ethanol, and drying to obtain a molecular sieve containing a hydrophilic group on the outside;

(22) dispersing the molecular sieve containing a hydrophilic group on the outside in 50 ml of toluene, and then adding thereto 1 mL of cetyltrimethoxysilane; heating in a water bath at 80 C. for 6 hours, centrifuging and drying, to obtain ZSM-5 having hydrophilic and lipophilic functional groups.

(23) The appearance of the sample obtained in this example has a partial half-shell structure and a partial full-shell structure, and this phenomenon can be regulated by changing the alkali etching time and the alkali concentration.

Example 4

(24) This example provides an amphiphilic molecular sieve containing a hydrophilic group on the outside and a lipophilic group on the inside obtained by the following steps:

(25) stirring 5 g of tetrapropylammonium hydroxide, 10 g of deionized water, 0.6 g of 1 mol/L sodium hydroxide solution, 0.1 g of aluminum source (aluminum isopropoxide powder), 10 mL of silicon source (ethyl orthosilicate) sufficiently and reacting under hydrothermal conditions for 24 h; centrifuging, washing, drying and sintering to finally obtain a precursor ZSM-5 molecular sieve;

(26) dispersing the precursor in 50 mL of toluene, and then adding thereto 1 mL of KH550; heating in a water bath at 60 C. for 4 hours, centrifuging and drying, to obtain a molecular sieve containing a hydrophilic group;

(27) adding the molecular sieve containing a hydrophilic group to a 0.5 mol/L NaOH solution, and treating in a water bath at 65 C. for 20 min, washing by centrifugation with water and ethanol, and drying to obtain a molecular sieve containing a hydrophilic group on the outside;

(28) dispersing the molecular sieve containing a hydrophilic group on the outside in 50 ml of toluene, and then adding thereto 1 mL of cetyltrimethoxysilane; heating in a water bath at 90 C. for 8 hours, centrifuging and drying, to obtain ZSM-5 having both hydrophilic and lipophilic functional groups.

(29) The position and thickness of the emulsified layer of the molecular sieve obtained according to this Example in decalin and saline are completely the same as those in Example 1, which indicates that the time and temperature in the organosilane modification reaction have no effect on the reaction within a certain range.

(30) It can be seen from the above examples that the degree of hydrophilicity and lipophilicity of the molecular sieve can be adjusted by changing the alkali etching conditions, and the organosilane modification conditions do not affect the molecular sieve within a certain range

(31) The above examples illustrate that the production method of the amphiphilic molecular sieve containing a hydrophilic group on the outside and a lipophilic group on the inside of the present invention is simple and efficient, and the produced amphiphilic molecular sieve has uniform and controllable size, while maintaining the nature of the molecular sieve itself. The half shell contains microporous channels, and the outer surface contains a hydrophilic group and the inside has a lipophilic character.