Efficient collection of nanoparticles

Patent metadata

Field	Value
Publication number	US-2016244547-A1
Application number	US-201415027657-A
Country	US
Kind code	A1
Filing date	Aug 15, 2014
Priority date	Oct 10, 2013
Publication date	Aug 25, 2016
Grant date	—

Abstract

An improved processing technique that can be used to collect nanoparticles produced by the RESS process. The collection efficiency by almost an order of magnitude compared to the traditional collection processes. One process does not utilize any stabilizing solid co-solvents but produces similar effects using the supercritical solvent itself (e.g. CO 2 ) as a stabilizing phase. Very small particles (diameter <10 nm) with uniform size distribution and particulate suspensions thereof may be produced.

First claim

What is claimed is:

1 . A process comprising:
expanding a supercritical solution of a compound of interest through a capillary at supersonic speeds; creating a stream of nanoparticles dispersed in a gaseous medium; cooling the stream of nanoparticles below the freezing point of the gaseous dispersion medium at least in part via application of external cooling provided by liquid coolant; and capturing the nanoparticles in a solid matrix via a gas-to-solid phase change.

2 . The process of claim 1 , wherein the cooling further comprises utilizing local cooling in the stream due to the Joule-Thomson effect.

3 . The process of claim 1 , wherein the liquid coolant is liquid nitrogen.

4 . The process according to claim 1 , wherein the supercritical solution comprises the compound of interest, a supercritical solvent, and a solid co-solvent.

5 . The process according to claim 4 , wherein the sublimation point of the supercritical solvent comprises CO 2 at atmospheric pressure is above 77K.

6 . The process according to claim 1 , wherein the supercritical solution comprises no solid co-solvent.

7 . The process according to claim 1 , wherein greater than 80% of the nanoparticles with diameter between about 1-100 nm are captured.

8 . The process according to claim 1 , wherein greater than 90% of the nanoparticles with diameter between about 1-100 nm are captured.

9 . The process according to claim 1 wherein the captured nanoparticles have an average size of less than 50 nm.

10 . The process according to claim 1 wherein the captured nanoparticles have an average size of less than 20 nm.

11 . The process according to claim 1 wherein the captured nanoparticles have an average size of less than 10 nm.

12 . The process according to claim 11 , wherein the captured nanoparticles have an average size of about 2 nm.

13 . The process according to claim 1 , wherein greater than 80% of the nanoparticles with diameter between about 2-100 nm are captured.

14 . The process according to claim 1 , wherein the cooling of the jet of ultra-fine particles occurs at or below pressure of 300 bar.

15 . The process of claim 1 wherein capturing the nanoparticles comprises the formation of solid carbon dioxide on the nanoparticles.

16 . A nontransitory computer-readable memory having instructions thereon, the instructions comprising:
instructions for controlling expansion of a supercritical solution of a compound of interest through a jet of nanoparticles particles dispersed in a gas; instructions for cooling the jet of ultra-fine particles below the sublimation point of the gaseous dispersion medium at least in part via application of external cooling provided by liquid coolant; and wherein the nanoparticles are separated are captured in a solid matrix via a gas-to-solid phase change.

17 . The nontransitory computer-readable memory of claim 16 , wherein the cooling further comprises utilizing the local cooling in the jet due to the Joule-Thomson effect.

18 . The nontransitory computer-readable memory of claim 16 , wherein the liquid coolant is liquid nitrogen.

19 . The nontransitory computer-readable memory according to claim 16 , wherein gas comprises CO 2 and the sublimation point of a supercritical solvent comprises CO 2 at atmospheric pressure is above 77K.

20 . The nontransitory computer-readable memory according to claim 16 , wherein greater than 90% of the nanoparticles particles with diameter between about 5-100 nm are captured.

21 . The nontransitory computer-readable memory according to claim 16 , wherein the cooling of the jet of nanoparticles particles occurs at or below pressure of 300 bar.

22 . The nontransitory computer-readable memory of claim 16 wherein capturing the nanoparticles comprises the formation of solid carbon dioxide on the nanoparticles particles.

23 . A system for collecting nanopoarticles comprising:
a feed system for providing compound of interest; a feed cooling system having a pump, a cooling bath, and a heat exchange, the feed cooling system providing a supercritical solution of the compound of interest to a high pressure vessel; the high-pressure vessel, which is divided by a piston head, into a formulation chamber and a control chamber; and a coolant vessel in communication with the high-pressure vessel through a capillary tube.

24 . The system of claim 23 , wherein the formulation chamber comprises a stirrer.

25 . The system of claim 23 , wherein the he formulation chamber further includes one or more viewing windows.

26 . The system of claim 23 , wherein the formulation chamber comprises a heater.

27 . The system of claim 23 , wherein the piston is a gas-tight, floating piston head.

Assignees

• Univ New York

Inventors

• Jagannathan Ramesh
• Khapli Sachin

Classifications

• A61K9/5146

  obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polyethylene glycol, polyamines, polyanhydrides · CPC title

• B01J3/008 Primary

  Processes carried out under supercritical conditions · CPC title

• A61K9/5192

  Processes · CPC title

• B01J3/04

  Pressure vessels, e.g. autoclaves · CPC title

• C08F224/00 Primary

  Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a heterocyclic ring containing oxygen (cyclic esters of polyfunctional acids C08F218/00; cyclic anhydrides of unsaturated acids C08F220/00, C08F222/00) · CPC title