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Results for “Aldehydes”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Electrocatalytic Reductive Amination of Aldehydes and Ketones with Aqueous Nitrite

The electrocatalytic utilization of oxidized nitrogen waste for C–N coupling chemistry is an exciting research area with great potential to be adopted as a sustainable method for generation of organonitrogen molecules. The most widely used C–N coupling reaction is reductive amination. In this work, we develop an alternative electrochemical reductive amination reaction that can proceed in neutral aqueous electrolyte with nitrite as the nitrogenous reactant and via an oxime intermediate. We develop a selection criterion for nitrite reduction electrocatalysts suited for oxime electrosynthesis and, in doing so, find Pd to be a highly efficient catalyst for this reaction, reaching an oxime Faradaic efficiency of 82% at −0.21 V vs the reversible hydrogen electrode. The aliphatic or aromatic structure of the carbonyl reactant impacts the efficacy of the catalyst, with aromatic substrates leading to suppressed oxime formation and detrimental reduction of the carbonyl to the alcohol. We developed a Pb/PbO electrocatalyst that selectively performs oxime reduction in the neutral aqueous electrolyte. With acetone as a model substrate, we demonstrate an efficient one-pot, two-step electrochemical reaction for the conversion of acetone to isopropyl amine with 85% yield and 50% global Faradaic efficiency.

catalysts↗
DOE OSTI2025

Surface engineering of Pt nanocatalysts with transition metal oleates for selective catalysis: a case study on the hydrogenation of α,β-unsaturated aldehydes

Selective and active catalysts enable effective use of feedstocks, reduced energy consumption and waste generation. Tuning the electronic structure of heterogeneous metal nanocatalysts via their surface modifications is a promising strategy to design highly selective and active catalysts for the synthesis of harder to make and more cost-efficient products. Here, we introduce transition metal oleates as a new class of ligands to engineer the catalytically active and very selective surface in organic solvents. Using citral hydrogenation and 5 nm Pt NPs as a model reaction and model catalytic system, respectively, we show that surface engineering of Pt nanocatalysts with metal oleates allows synthesis of desired partially hydrogenated product (geraniol) with ∼90% conversion with selectivity over 93%. We demonstrate that the selective synthesis of the unsaturated alcohols catalyzed by Pt NPs modified by adsorption of the transition metal salts cannot be explained by the widely accepted mechanism of preferred coordination of C$=$O groups by Lewis acids (e.g. partially oxidized transition surface metals). Our results indicate that C$=$O groups prefer to bind to negatively charged surfaces. We propose the explanation on how the adsorption of transition metal oleates can result in the increased electron density at the surface of Pt nanoparticles. Our study not only provides reliable solutions to selective hydrogenation but opens a new possibility of using metal oleates for the electronic ligand effect.

Kwon, Soon Gu [Argonne National Laboratory (ANL), ↗
DOE OSTI2026

Low-voltage syngas synthesis via BPM electrolysis of CO 2 capture and aldehyde solution

A bipolar membrane electrolyzer coupling bicarbonate electrolysis with formaldehyde oxidation directly produces syngas (H 2 : CO = 1) at 1.7 V and 200 mA cm −2 with 200% combined Faradaic efficiency. We demonstrate an electrochemical syngas production platform that couples bicarbonate electrolysis with formaldehyde oxidation in a bipolar membrane electrode assembly. This strategy doubles syngas (CO + H 2 ) throughput compared to conventional CO 2 electrolysis by generating CO at the cathode and H 2 at the anode. The system achieves a full-cell voltage of 1.7 V while operating at an industrially relevant current density of 200 mA cm −2 . The system maintained a combined Faradaic efficiency of 200% over 8 hours. The process produces syngas with a 1 : 1 H 2 : CO ratio, aligning with downstream requirements for Fischer–Tropsch synthesis. We further investigated how Cu anode active sites and electrolyte composition affect formaldehyde oxidation activity. Our integrated electrolytic system reduces levelized energy by 45–61% relative to conventional electrochemical syngas production platforms.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Chemically Amplified, Dry-Develop Poly(aldehyde) Photoresist

The catalytic decomposition of poly(phthalaldehyde) with a photoacid generator can be used as dry-develop photoresist, where the exposed film depolymerizes into small molecules to allow the development of features via controlled vaporization. Higher temperatures enabled shorter dry-development times, but also promoted faster photoacid diffusion that compromised pattern fidelity. Trihexylamine was used as a base quencher to counteract acid diffusion in a phthalaldehyde-propanal co-polymer photoresist. The propanal co-monomer in the polymer improves the vaporization rate because it has a higher vapor pressure than phthalaldehyde. Addition of the base quencher was found to improve the contrast, pattern fidelity, and ease-of-handling of the dry-develop resist in a direct-write UV lithography tool. The dry-development of 4 μ m features was achieved with no appreciable residue. For large area features, a spatially variable exposure method was used to direct the residue away from the exposed area. The gradient exposure method was used to produce 100 μ m features. Plasma etching after dry-development was also used to achieve residue-free dry-developed patterns. These results show the benefits of incorporating base additives into a dry-develop depolymerizable resist system and highlight the need for addressing residue formation.

Materials Science↗
NASA NTRS1984

Hydrogen atom migration in the oxidation of aldehydes - O(3P) + H2CO

An ab initio study of hydrogen atom migration in methylenebis(oxy)H2CO2(3B2) to form triplet formic acid HCOOH (3A1) is reported. From HF, MCHF, and CI calculated energy barriers, the activation energy is estimated to be no less than 30 kcal/mol. It is concluded that the hydrogen migration channel is not accessible in recent room temperature experiments on the O(3P) + H2CO reaction.

Dupuis, M.↗
NASA NTRS1984

Hydrogen atom abstraction from aldehydes - OH + H2CO and O + H2CO

The essential features of the potential energy surfaces governing hydrogen abstraction from formaldehyde by oxygen atom and hydroxyl radical have been characterized with ab inito multiconfiguration Hartree-Fock (MCHF) and configuration interaction (CI) wave functions. The results are consistent with a very small activation energy for the OH + H2CO reaction, and an activation energy of a few kcal/mol for the O + H2CO reaction. In the transition state structure of both systems, the attacking oxygen atom is nearly collinear with the attacked CH bond.

Dupuis, M.↗
NASA NTRS1989

Nonaggregating Microspheres Containing Aldehyde Groups

Cobalt gamma irradiation of hydrophilic monomers in presence of acrolein yields exceptionally-stable, nonaggregating microspheres. Mixtures of 2-hydroxyethyl methacrylate (HEMA) and acrolein form homogeneous solutions in distilled water containing 0.4 percent polyethylene oxide (PEO). After deaeration with nitrogen, mixtures irradiated at room temperature with gamma rays from cobalt source; total exposure time 4 hours, at rate of 0.2 milliroentgen per hour. Reaction product centrifuged three times for purification and kept in distilled water.

Rembaum, Alan↗