Metal nanoparticles stabilized with derivatized polyethyleneimines or polyvinylamines

Abstract

The invention relates to metal nanoparticles and a process for the preparation thereof, in which a metal salt solution is reduced with a reducing agent in the presence of the derivatized polyethyleneimines or polyvinylamines. Metal salt solutions of two or more different metals can be reduced simultaneously or in succession, metal nanoparticles comprising two or more different metals being obtained. Preferred metals are silver, palladium, and platinum. Suitable reducing agents are, for example, formic acid, formaldehyde, diethanolamine, 5-pentenoic acid and sodium borohydride. Silver can be used in the form of silver oxide and/or silver nitrate, palladium in the form of alkali metal tetrachloropalladate or palladium(II) nitrate and platinum in the form of alkali metal tetrachloroplatinate or tetraamineplatinum(II) nitrate.

1 .- 15 . (canceled) 
     
     
         16 . A metal nanoparticle which is stabilized with derivatized polyethyleneimines or polyvinylamines, wherein the polyethyleneimines and polyvinylamines are any one or more selected from the group consisting of:
 A Homopolymers of ethyleneimine (aziridine);   B Graft polymers of polyamidoamines with ethyleneimine;   C Graft polymers of polyvinylamines with ethyleneimine;   D Polymers of higher homologs of ethyleneimine;   E At least partly hydrolyzed N-vinylcarboxamide homopolymers; and   F At least partly hydrolyzed N-vinylcarboxamide copolymers, wherein the polyalkyleneimines and polyvinylamines are derivatized at the nitrogen atoms by reaction with alpha,beta-unsaturated carbonyl compounds by Michael addition.   
     
     
         17 . The metal nanoparticle of  claim 16 , wherein the alpha, beta-unsaturated carbonyl compound is any one or more selected from the group consisting of acrylic acid, acrylic acid esters, methacrylic acid, methacrylic acid esters, acrolein and acrylonitrile. 
     
     
         18 . The metal nanoparticle of  claim 16 , wherein a derivatized polyethyleneimine is employed, obtainable by reaction of a homopolymer of ethyleneimine with a diepoxide and/or bischlorohydrin ether and subsequent reaction with an alpha, beta-unsaturated carbonyl compound. 
     
     
         19 . The metal nanoparticle of  claim 18 , wherein the bischlorhydrin ether is 1,6-hexanediol ether or the bisglycidylether of a polyalkylene glycol. 
     
     
         20 . The metal nanoparticle of  claim 18 , wherein the alpha, beta-unsaturated carbonyl compound is selected from (meth)acrylic acid, alkyl(meth)acrylate and hydroxyalkyl(meth)acrylate. 
     
     
         21 . The metal nanoparticle of  claim 16 , wherein a derivatized polyethyleneimine is employed which is obtainable by reaction of a homopolymer of ethyleneimine with acrylic acid, hydroxyalkylacrylates and/or acrylamides. 
     
     
         22 . The metal nanoparticle of  claim 16 , wherein a derivatized polyethyleneimine is employed, which is obtainable by reaction of a graft polymer of polyamidoamine with ethyleneimine with acrylic acid. 
     
     
         23 . The metal nanoparticle of  claim 22 , wherein the graft polymer of polyamidoamine and ethyleneimine is first reacted with a diepoxide and/or bischlorohydrinether and subsequently with acrylic acid. 
     
     
         24 . The metal nanoparticle of  claim 16 , wherein the metal is any one or more selected from the group consisting of copper, silver gold, palladium, nickel, platinum, rhodium, iron, bismuth, iridium, ruthenium, rhenium, cobalt and osmium. 
     
     
         25 . A process for the preparation of metal nanoparticles of  claim 16 , in which a metal salt solution is reduced with a reducing agent in the presence of the derivatized polyethyleneimines or polyvinylamines. 
     
     
         26 . The process of  claim 25 , wherein metal salt solutions of two or more different metals are reduced simultaneously or in succession, metal nanoparticles comprising two or more different metals being obtained. 
     
     
         27 . The process of  claim 25 , wherein the reducing agent is any one or more selected from formic acid, formaldehyde, diethanolamine, 5-pentenoic acid, hydrazine, oxalic acid, sodium borohydride, ethanol, methanol, ethylene glycol and diethylene glycol. 
     
     
         28 . The process of  claim 25 , wherein silver as used in the form of silver oxide, silver acetate and/or silver nitrate. 
     
     
         29 . The process of  claim 25 , wherein the solvent used is water. 
     
     
         30 . The process of  claim 25 , wherein the solvent used is a polyhydric alcohol.