Carbon monoxide-driven reductive organic transformations and precious metals recycling
type: CreativeWork
description: Herein we present the efforts made toward employing the homogeneously-catalyzed Water-Gas Shift Reaction (WGSR) to drive essential reductive chemical transformations, and selectively extract rhodium from solid waste. The generation of rhodium hydride from the reaction of rhodium carbonyl with water has been achieved at temperatures as low as room temperature when the reaction was performed in a solution of simple tertiary amines in polar solvents. We investigated the mechanism by which this reaction proceeds and studied the effect of the reaction parameters on the ability of rhodium to deliver its hydride to different reducible functional groups e.g. activated alkenes, aldehydes, and ketones. We demonstrated the ability of the WGSR to drive the reductive alkylation of several classes of activated methylene compounds at room temperature. Under catalysis by rhodium trichloride (2–3 mol %), carbon monoxide (10 bar), water (2–50 equiv), and tertiary methyl /ethyl amines (2.5–7 equiv), the scope has been successfully expanded to cover a wide range of alkylating agents, including aliphatic and aromatic aldehydes, as well as cyclic ketones, in moderate to high yields. This method is comparable to, and for certain aspects, surpasses the established reductive alkylation protocols. The reductive amination of aldehydes has been demonstrated to be feasible under the same conditions with the exception of furfurals which undergo a newly-identified, reductive Piancatelli rearrangement to yield 2-enoneamines. A novel Pd/Rh dual‐metallic cooperative catalytic process has been developed to effect the reductive carbonylation of aryl halides in moderate to good yield. In this reaction, water is the hydride source, and CO serves both as the carbonyl source and the terminal reductant through the water–gas shift reaction. The catalytic generation of the Rh hydride allows for the selective formation of highly hindered aryl aldehydes that are inaccessible through previously reported reducti…
abstract: Herein we present the efforts made toward employing the homogeneously-catalyzed Water-Gas Shift Reaction (WGSR) to drive essential reductive chemical transformations, and selectively extract rhodium from solid waste. The generation of rhodium hydride from the reaction of rhodium carbonyl with water has been achieved at temperatures as low as room temperature when the reaction was performed in a solution of simple tertiary amines in polar solvents. We investigated the mechanism by which this reaction proceeds and studied the effect of the reaction parameters on the ability of rhodium to deliver its hydride to different reducible functional groups e.g. activated alkenes, aldehydes, and ketones. We demonstrated the ability of the WGSR to drive the reductive alkylation of several classes of activated methylene compounds at room temperature. Under catalysis by rhodium trichloride (2–3 mol %), carbon monoxide (10 bar), water (2–50 equiv), and tertiary methyl /ethyl amines (2.5–7 equiv), the scope has been successfully expanded to cover a wide range of alkylating agents, including aliphatic and aromatic aldehydes, as well as cyclic ketones, in moderate to high yields. This method is comparable to, and for certain aspects, surpasses the established reductive alkylation protocols. The reductive amination of aldehydes has been demonstrated to be feasible under the same conditions with the exception of furfurals which undergo a newly-identified, reductive Piancatelli rearrangement to yield 2-enoneamines. A novel Pd/Rh dual‐metallic cooperative catalytic process has been developed to effect the reductive carbonylation of aryl halides in moderate to good yield. In this reaction, water is the hydride source, and CO serves both as the carbonyl source and the terminal reductant through the water–gas shift reaction. The catalytic generation of the Rh hydride allows for the selective formation of highly hindered aryl aldehydes that are inaccessible through previously reported reducti…
author: Ibrahim, Malek Y. S.
language: en
keywords: Water-Gas Shift, rhodium carbonyl hydride, reductive carbonylation, alkylation, amination, rhodium recycling.
date published: 2019-02-06T19:32:44Z
date modified: 2026-07-22T22:24:40Z
provider: University of Illinois - Urbana-Champaign
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Illinois at Urbana-Champaign

PropertyValue
property ID: Handle
value: http://hdl.handle.net/2142/102409