Method for producing nanoparticles from a liquid mixture

Patent metadata

Field	Value
Publication number	US-2020231438-A1
Application number	US-201816494695-A
Country	US
Kind code	A1
Filing date	Mar 16, 2018
Priority date	Mar 17, 2017
Publication date	Jul 23, 2020
Grant date	—

Abstract

A process for the production of nanoparticles from a liquid mixture comprising at least one precursor and at least one solvent in a reactor with continuous through-flow comprises the steps of feeding at least one oxygen-containing gas inflow stream having a temperature into the at least one reactor, adding at least one fuel having a temperature to the oxygen-containing gas inflow stream, wherein the fuel and the oxygen-containing gas inflow stream form a homogeneous ignitable mixture having a temperature, wherein the temperature of the homogeneous ignitable mixture is above the autoignition temperature of the homogeneous ignitable mixture, introducing at least one precursor-solvent mixture into the homogeneous ignitable mixture; autoignition of the ignitable mixture of oxygen-containing gas and fuel after an ignition delay time to form a stabilized flame and reacting the precursor-solvent mixture in the stabilized flame to form nanoparticles from the metal salt precursor, removing the formed nanoparticles.

First claim

1 . A process for the production of nanoparticles from a liquid mixture comprising at least one precursor and at least one solvent in a reactor with continuous through-flow, comprising:
a) feeding at least one oxygen-containing gas inflow stream having a temperature T I into the at least one reactor, b) adding at least one fuel having a temperature T F to the oxygen-containing gas inflow stream, wherein the fuel and the oxygen-containing gas inflow stream form a homogeneous ignitable mixture having a temperature T IM , wherein the temperature of the homogeneous ignitable mixture T IM is above the autoignition temperature T AIM of the homogeneous ignitable mixture, c) introducing at least one precursor-solvent mixture into the homogeneous ignitable mixture, d) autoignition of the ignitable mixture of oxygen-containing gas and fuel after an ignition delay time tip to form a stabilized flame and reacting the precursor-solvent mixture in the stabilized flame to form nanoparticles from the metal salt precursor, and e) removing the nanoparticles formed from the reactor.

2 . The process as claimed in claim 1 , wherein the homogeneous ignitable mixture has a flow velocity v IM in the reactor that is greater than the turbulent flame velocity v F of the flame formed from the ignitable mixture in step d) through autoignition.

3 . The process as claimed in claim 1 , wherein the flow velocity v IM of the oxygen-containing gas inflow stream is in a range between 5 and 200 m/s, preferably between 10 and 100 m/s.

4 . The process as claimed in claim 1 , wherein the oxygen-containing gas used is air or a mixture of oxygen with at least one inert gas, in particular nitrogen, carbon dioxide, argon.

5 . The process as claimed in claim 1 , wherein the temperature T I of the oxygen-containing gas inflow stream is in a range between 500-1500 K, preferably between 900-1400 K.

6 . The process as claimed in claim 1 , wherein the at least one fuel is a gaseous fuel and/or a liquid fuel.

7 . The process as claimed in claim 1 , wherein the air ratio λ of the ignitable mixture is in a range between 0.1 and 25, preferably in a range between 0.5 to 10, especially preferably in a range between 1 to 3.

8 . The process as claimed in claim 1 , wherein at least one precursor is a metal salt selected from the group of aluminum, barium, bismuth, calcium, cerium, iron, magnesium, platinum, palladium, strontium, titanium, zirconium, manganese, chromium, zinc, copper, nickel, cobalt, yttrium, silver, vanadium, molybdenum or other metals or metalloids.

9 . The process as claimed in claim 1 , wherein the precursor-solvent mixture is injected/sprayed into the homogeneous ignition mixture through at least one nozzle or atomizer.

10 . The process as claimed in claim 9 , wherein the precursor-solvent mixture is injected using an ultrasonic atomizer or a pressure-controlled injection nozzle.

11 . The process as claimed in claim 1 , wherein the solvent for the metal salt-precursor-solvent mixture is selected from a group including water or an organic solvent.

12 . The process as claimed in claim 1 , wherein the ignition delay time t ID is in a range between 1 μs to 1 s, preferably 1 ms to 200 ms, in particular 10 ms to 100 ms.

13 . The process as claimed in claim 1 , the nanoparticles produced have a particle diameter with a d95 value of less than 1000 nm, preferably less than 800 nm, especially preferably less than 500 nm.

14 . A reactor for the execution of a process as claimed in claim 1 , comprising:
a first section A having at least one means of introducing an oxygen-containing gas stream into the reactor; a second section B provided downstream of the first section A, having at least one means for introducing at least one fuel into the reactor; a third section C provided downstream of the first section A, having at least one means for injecting the at least one precursor-solvent mixture into the reactor; a fourth section D provided downstream of the second section B and third section C, for autoignition of the ignitable mixture of oxygen-containing gas and fuel; and a fifth section E provided downstream of section D, for the formation and removal from the reactor of the nanoparticles formed.

15 . The reactor as claimed in claim 14 , wherein the distance x between section B, in which the fuel is introduced, and section D, in which the autoignition of the ignitable mixture takes place, is given by the equation x=v IM *t ID .

Assignees

• Univ Berlin Tech

Inventors

• Schimek Sebastian
• Paschereit Christian Oliver
• Sieber Moritz

Classifications

• C01G9/03

  Processes of production using dry methods, e.g. vapour phase processes · CPC title

• C01B33/183

  by oxidation or hydrolysis in the vapour phase of silicon compounds such as halides, trichlorosilane, monosilane · CPC title

• C01B13/34 Primary

  by oxidation or hydrolysis of sprayed or atomised solutions · CPC title

• B01J21/04

  Alumina · CPC title

• B01J23/34

  Manganese · CPC title