	US 12,134,087 B2
	Method for preparing pickering miniemulsion and its catalytic application
Jieshan Qiu, Dalian (CN); Chang Yu, Dalian (CN); Lin Ni, Dalian (CN); and Ji Wen, Jiangyou (CN)
Assigned to Dalian University of Technology, Dalian (CN)
Filed by Dalian University of Technology, Dalian (CN)
Filed on Sep. 30, 2023, as Appl. No. 18/479,002.
Claims priority of application No. 202211218392.X (CN), filed on Oct. 5, 2022.
Prior Publication US 2024/0116040 A1, Apr. 11, 2024
Int. Cl. B01J 35/23 (2024.01); B01J 21/18 (2006.01); B01J 23/46 (2006.01); B01J 37/00 (2006.01); B01J 37/02 (2006.01); B01J 37/04 (2006.01); B01J 37/16 (2006.01); B01J 37/34 (2006.01); C07C 45/29 (2006.01)

CPC B01J 35/23 (2024.01) [B01J 21/18 (2013.01); B01J 23/462 (2013.01); B01J 37/009 (2013.01); B01J 37/0221 (2013.01); B01J 37/04 (2013.01); B01J 37/16 (2013.01); B01J 37/343 (2013.01); C07C 45/294 (2013.01)]

8 Claims

1. A method for constructing a Pickering miniemulsion catalytic system, comprising the following steps:

step 1, preparing a Pickering miniemulsion catalyst/emulsifier, specifically comprising:

step 1.1, preparation of surface-modified carbon quantum dots:

adding citric acid and an amine compound to absolute ethanol, and modifying carbon dots by using the amine compound as a modifier and the citric acid as a carbon source, and heating for obtaining orange liquid; wherein 1.5-3 g of the citric acid and 0.1-4 g of the amine compound are added into every 25 mL of the absolute ethanol;

dispersing the orange liquid into sodium hydroxide (NaOH) aqueous solution dropwise, and stirring the NaOH aqueous solution added with the orange liquid at 35-50° C. for 24-48 h to obtain a dispersion; wherein a volume ratio of the NaOH aqueous solution to the orange liquid is 20:1; and

centrifuging the dispersion to obtain a supernatant, treating the supernatant with 500 Dalton (DA) dialysis membrane for 24-48 h to remove small molecular impurities and obtain yellow carbon dots solution; placing the yellow carbon dots solution in an environment below −10° C. until the yellow carbon dots solution is completely frozen, and then drying in a freeze dryer to obtain carbon dots solid powder with a size of 8-12 nm;

step 1.2, preparation of an emulsion catalyst:

adding the carbon dots solid powder and a metal salt into a mixed solution of water and ethanol and then stirring for 3-6 h to obtain a system; wherein 20-1000 mg of the carbon dots solid powder and 1-50 mg of the metal salt are correspondingly added into every 50 mL of the mixed solution of water and ethanol, and a volume ratio of the water to the ethanol in the mixed solution of water and ethanol is 1:4; after standing the system for 6-18 h, adding sodium borohydride (NaBH₄) aqueous solution dropwise into the system to perform reduction for 0.5-2 h until the system becomes a black suspension, and centrifuging the black suspension to obtain a solid emulsion catalyst; wherein 10 mL of the NaBH₄aqueous solution with a concentration of 2 mg·mL⁻¹is correspondingly added to every 50 mL of the mixed solution of water and ethanol;

step 2, constructing the Pickering miniemulsion catalytic system, specifically comprising:

dispersing the obtained solid emulsion catalyst in water to prepare a dispersion A with a concentration of 0.05-5 wt %; adding the dispersion A to a vial with a water-immiscible organic solvent to obtain a mixture; wherein a volume ratio of the dispersion A to the organic solvent is 2:1; performing ultrasonic treatment on the mixture in the vial for 0.5-2 min, and then stirring the mixture for 10-20 min to emulsify the mixture and form a Pickering miniemulsion; and wherein a droplet size of the Pickering miniemulsion is in a range of 0.1-1 μm.