Shannon Stahl
University of Wisconsin-Madison
H-index: 114
North America-United States
Description
Shannon Stahl, With an exceptional h-index of 114 and a recent h-index of 71 (since 2020), a distinguished researcher at University of Wisconsin-Madison,
His recent articles reflect a diverse array of research interests and contributions to the field:
Economical methods for performing oxidative catalytic pretreatment of plant biomass using a single-stage two oxidant process
Recovery of p-Hydroxybenzoic Acid from Cu-Catalyzed Alkaline Hydrogen Peroxide Pretreatment of Hybrid Poplar
Scale-Up of a Two-Stage Cu-Catalyzed Alkaline-Oxidative Pretreatment of Hybrid Poplar
Mechanistic insights into radical formation and functionalization in copper/N-fluorobenzenesulfonimide radical-relay reactions
Divergent Bimetallic Mechanisms in Copper (II)-Mediated C–C, N–N, and O–O Oxidative Coupling Reactions
Cyclic voltammetry and chronoamperometry: mechanistic tools for organic electrosynthesis
Catalytic carbon–carbon bond cleavage in lignin via manganese–zirconium-mediated autoxidation
Synthetic dioxygenase reactivity by pairing electrochemical oxygen reduction and water oxidation
Professor Information
University | University of Wisconsin-Madison |
---|---|
Position | Department of Chemistry |
Citations(all) | 42763 |
Citations(since 2020) | 19057 |
Cited By | 31191 |
hIndex(all) | 114 |
hIndex(since 2020) | 71 |
i10Index(all) | 289 |
i10Index(since 2020) | 260 |
University Profile Page | University of Wisconsin-Madison |
Top articles of Shannon Stahl
Economical methods for performing oxidative catalytic pretreatment of plant biomass using a single-stage two oxidant process
An improved alkaline pretreatment of biomass is provided that is a single-stage, two oxidant alkaline oxidative pretreatment process. The process uses a homogenous catalyst with at least two oxidants (Hydrogen peroxide and enhanced levels of oxygen) in an alkaline environment to catalytically pretreat lignocellulosic biomass in a single-stage oxidation reaction. The provided single-stage alkaline-oxidative pretreatment improves biomass pretreatment and increase enzymatic digestibility to improve the economic feasibility of production of lignocellulose derived sugars.
Published Date
2024/1/2
Recovery of p-Hydroxybenzoic Acid from Cu-Catalyzed Alkaline Hydrogen Peroxide Pretreatment of Hybrid Poplar
p-Hydroxybenzoic acid (pHBA) is present in some hardwood biomass feedstocks as an ester attached to the polymeric lignin subunits. Here, we report the isolation and recovery of pHBA from alkaline liquor waste streams obtained from fractionation of hybrid poplar using the “Cu-AHP process”. This process features two stages: alkaline pre-extraction (AP) of the biomass and copper-catalyzed alkaline hydrogen peroxide pretreatment. On a biomass scale of 100 g, 0.5 g of pHBA with a purity of 96% was obtained after decolorization and crystallization. The scalability of the purification process was demonstrated by using liquor obtained from the first-stage AP with 900 g of poplar biomass to afford 3.5 g of crystalline pHBA with 97% purity. Overall, these results show that pHBA may be isolated and purified from waste streams generated in the two-stage Cu-AHP process without any alteration of the process conditions or …
Authors
Surajudeen Omolabake,Christopher Holland,Dilara Naz Dülger,Zhaoyang Yuan,Eric L Hegg,David B Hodge,Shannon S Stahl
Journal
ACS Sustainable Chemistry & Engineering
Published Date
2024/4/5
Scale-Up of a Two-Stage Cu-Catalyzed Alkaline-Oxidative Pretreatment of Hybrid Poplar
A two-stage alkaline-oxidative pretreatment of hybrid poplar was investigated at scale (20 L reactor volume) with the goal of understanding how reaction conditions as well as interstage mechanical refining impact downstream process responses. The pretreatment comprises a first stage of alkaline delignification (alkaline pre-extraction) followed by a second delignification stage employing Cu-catalyzed alkaline hydrogen peroxide with supplemental O2 (O2-enhanced Cu-AHP). Increasing pre-extraction severity (i.e., temperature and alkali loading) and pretreatment oxidation (increasing H2O2 loading) were found to increase mass and lignin solubilization in each stage. Lignin recovered from the first stage was subjected to oxidative depolymerization and led to aromatic monomer yields as high as 23.0% by mass. Lignins recovered from the second-stage Cu-AHP pretreatment liquors were shown to exhibit aliphatic …
Authors
Dilara N Dülger,Zhaoyang Yuan,Sandip K Singh,Surajudeen Omolabake,Celeste R Czarnecki,Saeid Nikafshar,Mingfei Li,Villő E Bécsy-Jakab,Seonghyun Park,Sunkyu Park,Mojgan Nejad,Shannon S Stahl,Eric L Hegg,David B Hodge
Journal
Industrial & Engineering Chemistry Research
Published Date
2024/3/26
Mechanistic insights into radical formation and functionalization in copper/N-fluorobenzenesulfonimide radical-relay reactions
Copper-catalysed radical-relay reactions that employ N-fluorobenzenesulfonimide (NFSI) as the oxidant have emerged as highly effective methods for C(sp3)–H functionalization. Herein, computational studies are paired with experimental data to investigate a series of key mechanistic features of these reactions, with a focus on issues related to site-selectivity, enantioselectivity, and C–H substrate scope. (1) The full reaction energetics of enantioselective benzylic C–H cyanation are probed, and an adduct between Cu and the N-sulfonimidyl radical (˙NSI) is implicated as the species that promotes hydrogen-atom transfer (HAT) from the C–H substrate. (2) Benzylic versus 3° C–H site-selectivity is compared with different HAT reagents: Cu/˙NSI, ˙OtBu, and Cl˙, and the data provide insights into the high selectivity for benzylic C–H bonds in Cu/NFSI-catalyzed C–H functionalization reactions. (3) The energetics of three …
Authors
Mukunda Mandal,Joshua A Buss,Si-Jie Chen,Christopher J Cramer,Shannon S Stahl
Journal
Chemical Science
Published Date
2024
Divergent Bimetallic Mechanisms in Copper (II)-Mediated C–C, N–N, and O–O Oxidative Coupling Reactions
Copper-catalyzed aerobic oxidative coupling of diaryl imines provides a route for conversion of ammonia to hydrazine. The present study uses experimental and density functional theory computational methods to investigate the mechanism of N–N bond formation, and the data support a mechanism involving bimolecular coupling of Cu-coordinated iminyl radicals. Computational analysis is extended to CuII-mediated C–C, N–N, and O–O coupling reactions involved in the formation of cyanogen (NC–CN) from HCN, 1,3-butadiyne from ethyne (i.e., Glaser coupling), hydrazine from ammonia, and hydrogen peroxide from water. The results reveal two different mechanistic pathways. Heteroatom ligands with an uncoordinated lone pair (iminyl, NH2, OH) undergo charge transfer to CuII, generating ligand-centered radicals that undergo facile bimolecular radical–radical coupling. Ligands lacking a lone pair (CN and CCH …
Authors
Daniel S King,Fei Wang,James B Gerken,Carlo Alberto Gaggioli,Ilia A Guzei,Yeon Jung Kim,Shannon S Stahl,Laura Gagliardi
Journal
Journal of the American Chemical Society
Published Date
2024/1/29
Cyclic voltammetry and chronoamperometry: mechanistic tools for organic electrosynthesis
Electrochemical methods offer unique advantages for chemical synthesis, as the reaction selectivity may be controlled by tuning the applied potential or current. Similarly, measuring the current or potential during the reaction can provide valuable mechanistic insights into these reactions. The aim of this tutorial review is to explain the use of cyclic voltammetry and chronoamperometry to interrogate reaction mechanisms, optimize electrochemical reactions, or design new reactions. Fundamental principles of cyclic voltammetry and chronoamperometry experiments are presented together with the application of these techniques to probe (electro)chemical reactions. Several diagnostic criteria are noted for the use of cyclic voltammetry and chronoamperometry to analyze coupled electrochemical–chemical (EC) reactions, and a series of individual mechanistic studies are presented. Steady state voltammetric and …
Authors
Mohammad Rafiee,Dylan J Abrams,Luana Cardinale,Zachary Goss,Antonio Romero-Arenas,Shannon S Stahl
Published Date
2024
Catalytic carbon–carbon bond cleavage in lignin via manganese–zirconium-mediated autoxidation
Efforts to produce aromatic monomers through catalytic lignin depolymerization have historically focused on aryl–ether bond cleavage. A large fraction of aromatic monomers in lignin, however, are linked by various carbon–carbon (C–C) bonds that are more challenging to cleave and limit the yields of aromatic monomers from lignin depolymerization. Here, we report a catalytic autoxidation method to cleave C–C bonds in lignin-derived dimers and oligomers from pine and poplar. The method uses manganese and zirconium salts as catalysts in acetic acid and produces aromatic carboxylic acids as primary products. The mixtures of the oxygenated monomers are efficiently converted to cis,cis-muconic acid in an engineered strain of Pseudomonas putida KT2440 that conducts aromatic O-demethylation reactions at the 4-position. This work demonstrates that autoxidation of lignin with Mn and Zr offers a catalytic …
Authors
Chad T Palumbo,Nina X Gu,Alissa C Bleem,Kevin P Sullivan,Rui Katahira,Lisa M Stanley,Jacob K Kenny,Morgan A Ingraham,Kelsey J Ramirez,Stefan J Haugen,Caroline R Amendola,Shannon S Stahl,Gregg T Beckham
Journal
Nature Communications
Published Date
2024/1/29
Synthetic dioxygenase reactivity by pairing electrochemical oxygen reduction and water oxidation
The reactivity of molecular oxygen is crucial to clean energy technologies and green chemical synthesis, but kinetic barriers complicate both applications. In synthesis, dioxygen should be able to undergo oxygen atom transfer to two organic molecules with perfect atom economy, but such reactivity is rare. Monooxygenase enzymes commonly reductively activate dioxygen by sacrificing one of the oxygen atoms to generate a more reactive oxidant. Here, we used a manganese-tetraphenylporphyrin catalyst to pair electrochemical oxygen reduction and water oxidation, generating a reactive manganese-oxo at both electrodes. This process supports dioxygen atom transfer to two thioether substrate molecules, generating two equivalents of sulfoxide with a single equivalent of dioxygen. This net dioxygenase reactivity consumes no electrons but uses electrochemical energy to overcome kinetic barriers.
Authors
Md Asmaul Hoque,James B Gerken,Shannon S Stahl
Journal
Science
Published Date
2024/1/12
Professor FAQs
What is Shannon Stahl's h-index at University of Wisconsin-Madison?
The h-index of Shannon Stahl has been 71 since 2020 and 114 in total.
What are Shannon Stahl's top articles?
The articles with the titles of
Economical methods for performing oxidative catalytic pretreatment of plant biomass using a single-stage two oxidant process
Recovery of p-Hydroxybenzoic Acid from Cu-Catalyzed Alkaline Hydrogen Peroxide Pretreatment of Hybrid Poplar
Scale-Up of a Two-Stage Cu-Catalyzed Alkaline-Oxidative Pretreatment of Hybrid Poplar
Mechanistic insights into radical formation and functionalization in copper/N-fluorobenzenesulfonimide radical-relay reactions
Divergent Bimetallic Mechanisms in Copper (II)-Mediated C–C, N–N, and O–O Oxidative Coupling Reactions
Cyclic voltammetry and chronoamperometry: mechanistic tools for organic electrosynthesis
Catalytic carbon–carbon bond cleavage in lignin via manganese–zirconium-mediated autoxidation
Synthetic dioxygenase reactivity by pairing electrochemical oxygen reduction and water oxidation
...
are the top articles of Shannon Stahl at University of Wisconsin-Madison.
What is Shannon Stahl's total number of citations?
Shannon Stahl has 42,763 citations in total.