Continuous Reaction Process For Preparing Metallic Nanoparticles

Abstract

A method for producing metallic nanoparticles in a continuous flow-through reactor comprising combining at least one metallic precursor and at least one radical precursor in a reactant reservoir to form a reactant stream; flowing the reactant stream through at least one channel having a first channel end connected to the reactant reservoir, a second channel end connected to a product reservoir, and at least one clear channel section, which is transparent to activating radiation used to generate a radical reducing agent from the radical precursor, for exposing the reactant stream to a radiation source; exposing the reactant stream in the clear channel section to the radiation source to generate the radical reducing agent, initiate a reaction, and form a product stream comprising metallic nanoparticles; and optionally, collecting the product stream in the product reservoir.

1 . A method for producing metallic nanoparticles in a continuous flow-through reactor comprising:
 combining at least one metallic precursor and at least one radical precursor in a reactant reservoir to form a reactant stream;   flowing the reactant stream through at least one channel having a first channel end connected to the reactant reservoir, a second channel end connected to a product reservoir, and at least one clear channel section, which is transparent to activating radiation used to generate a radical reducing agent from the radical precursor, for exposing the reactant stream to a radiation source;   exposing the reactant stream in the clear channel section to the radiation source to generate the radical reducing agent, initiate a reaction, and form a product stream comprising metallic nanoparticles; and   optionally, collecting the product stream in the product reservoir.   
     
     
         2 . The method of  claim 1 , wherein the at least one channel comprises a single channel having a plurality of branches extending therefrom, and wherein each branch has at least one clear channel section; or
 wherein the at least one channel comprises a plurality of channels, each channel having at least a first channel end connected to the reactant reservoir, a second channel end connected to the product reservoir, and at least one clear channel section for exposing the reactant stream to a radiation source.   
     
     
         3 . The method of  claim 1 , further comprising:
 providing a plurality of radiation sources; and   exposing the reactant stream in each clear channel section to at least one of the plurality of radiation sources.   
     
     
         4 . The method of  claim 1 , wherein the radiation source is an ultra-violet radiation source, a visible radiation source, or a combination thereof. 
     
     
         5 . The method of  claim 1 , wherein the clear channel section has a cross-section of from about 1 to about 4 millimeters. 
     
     
         6 . The method of  claim 1 , wherein the metallic precursor comprises one or more metallic salts. 
     
     
         7 . The method of  claim 1 , wherein the metallic nanoparticles are gold, silver, copper, platinum, palladium, nickel, lead, or combinations thereof. 
     
     
         8 . The method of  claim 1 , wherein the radical reducing agent is a ketyl radical or an α-amino radical. 
     
     
         9 . The method of  claim 1 , wherein the metallic nanoparticles are from about 5 nanometers to about 400 nanometers in size. 
     
     
         10 . A method for producing bimetallic or alloy nanoparticles in a continuous flow-through reactor comprising:
 combining at least one first metallic precursor and at least one radical precursor;   combining at least one second metallic precursor and at least one radical precursor;   wherein the first and second metallic precursors are the same or different; and wherein the first and second radical precursors are the same or different;   flowing the first metallic precursor, and first radical precursor, second metallic precursor, and second radical precursor through a first clear channel section of the reactor and exposing the metallic and radical precursors to a radiation source to initiate a reaction and form a product stream comprising metallic or bimetallic nanoparticles having a core-shell configuration, an alloy configuration, or a combination thereof; and   optionally, collecting the product stream in a product reservoir.   
     
     
         11 . The method of  claim 10 , wherein combining comprises combining at least one first metallic precursor and at least one first radical precursor in a first reactant reservoir to form a first reactant stream;
 combining at least one second metallic precursor and at least one second radical precursor in a second reactant reservoir to form a second reactant stream;   wherein the first and second metallic precursors are the same or different; and wherein the first and second radical precursors are the same or different;   flowing the first reactant stream through a first clear channel section of the reactor which is transparent to activating radiation used to generate a radical reducing agent from the radical precursor to expose the first reactant stream to a radiation source to initiate a reaction and form a first product stream comprising metallic nanoparticles;   combining the produced metallic nanoparticles with the second reactant stream downstream of the first clear channel section;   flowing the produced metallic nanoparticles and the second reactant stream through a second clear channel section of the reactor that is downstream of the first clear channel section;   exposing the produced metallic nanoparticles and the second reactant stream to the radiation source to initiate a reaction and form a second product stream comprising metallic or bimetallic nanoparticles having a core-shell configuration, an alloy configuration, or a combination thereof; and   optionally, collecting the second product stream in a second product reservoir.   
     
     
         12 . The method of  claim 10 , wherein combining comprises premixing the metallic precursors and radical precursors in a single reservoir; and
 flowing the mixture combined in the single reservoir through at least one clear channel section;   exposing the mixture in the clear channel section to the radiation source to initiate a reaction and form a product stream comprising metallic or bimetallic nanoparticles having a core-shell configuration, an alloy configuration, or a combination thereof; and   optionally, collecting the product stream in a product reservoir.   
     
     
         13 . The method of  claim 10 , wherein the radiation source is an ultra-violet radiation source, a visible radiation source, or a combination thereof. 
     
     
         14 . The method of  claim 10 , wherein the clear channel section has a cross-section of from about 1 to about 4 millimeters. 
     
     
         15 . The method of  claim 10 , wherein the metallic precursor comprises one or more metallic salts. 
     
     
         16 . The method of  claim 10 , wherein the metallic nanoparticles are gold, silver, copper, platinum, palladium, nickel, lead, or combinations thereof. 
     
     
         17 . The method of  claim 10 , wherein the radical is a ketyl radical or an α-amino radical. 
     
     
         18 . The method of  claim 10 , wherein the metallic nanoparticles are about 5 nanometers to about 400 nanometers in size. 
     
     
         19 . A continuous flow-through reactor system for producing metallic nanoparticles comprising:
 at least one reactant reservoir for combining at least one metallic precursor and at least one radical precursor in to form a reactant stream;   at least one product reservoir;   at least one channel having a first end fluidly connected to the reactant reservoir and a second end fluidly connected to the product reservoir for flowing the reactant stream there through, wherein the at least one channel has at least one clear channel section which is transparent to activating radiation used to generate a radical reducing agent from the radical precursor;   at least one device for causing the reactant stream to flow from the reactant reservoir through the clear channel section to the product reservoir;   at least one radiation source capable of exposing the reactant stream passing through the clear section channel.   
     
     
         20 . The continuous flow-through reactor system of  claim 19  comprising:
 at least one first reactant reservoir for combining at least one first metallic precursor and at least one first radical precursor in to form a first reactant stream; 
 at least one second reactant reservoir for combining at least one second metallic precursor and at least one second radical precursor in to form a second reactant stream; 
 wherein the first and second metallic precursors are the same or different; and wherein the first and second radical precursors are the same or different; 
 at least one first channel having at least one first clear channel section, a first end fluidly connected to the first reactant reservoir, and a second end fluidly connected to the product reservoir, for flowing the first reactant stream through the first clear channel section to expose the first reactant stream to a radiation source to initiate a reaction and form a first product stream comprising metallic nanoparticles; 
 at least one second channel having at least one second clear section, a first end fluidly connected to the second reactant reservoir, and a second end fluidly connected to the first channel downstream of the first clear channel section, for flowing the second reactant stream and the first product stream through the second clear channel section to product a second product stream comprising metallic or bimetallic nanoparticles having a core-shell configuration, an alloy configuration, or a combination thereof.