Related Experiment Video
Updated: Jul 8, 2026
![Solid-phase Synthesis of [4.4] Spirocyclic Oximes](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F58508.jpg&w=3840&q=50)
05:15
Solid-phase Synthesis of [4.4] Spirocyclic Oximes
Published on: February 6, 2019
Stabilized Bi(III) Sites Direct *NH2OH Pathway for Efficient Cyclohexanone Oxime Electrosynthesis
Zichao Xi1,2, Yan Du2, Haijing Li2
1College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, China.
Advanced Materials (Deerfield Beach, Fla.)
|July 7, 2026
Summary
This study introduces a novel BiPO4/SiOx catalyst for efficient cyclohexanone oxime electrosynthesis via nitrite reduction. The catalyst stabilizes key intermediates, boosting selectivity and yield for nylon-6 production.
Area of Science:
- Electrochemistry
- Catalysis
- Materials Science
Background:
- Electrosynthesis of cyclohexanone oxime (CHO) is crucial for nylon-6 production.
- Current methods struggle with selective intermediate formation, limiting efficiency.
- Nitrite reduction coupled with cyclohexanone conversion offers a sustainable pathway.
Purpose of the Study:
- To develop a catalyst enabling efficient and selective electrosynthesis of cyclohexanone oxime (CHO).
- To investigate the role of Bi(III) sites in controlling reaction pathways.
- To design a stable catalyst interface for sustained performance.
Main Methods:
- Design and synthesis of a BiPO4/SiOx catalyst interface.
- Electrocatalytic experiments in an H-cell setup.
- Combined experimental and theoretical analyses (DFT) to elucidate reaction mechanisms.
Main Results:
- The BiPO4/SiOx catalyst achieved a high Faradaic efficiency (FE_CHO) of 77.0 ± 3.4% and a yield rate of 0.64 ± 0.01 mmol h⁻¹ cm⁻².
- Demonstrated nearly 100% carbon and nitrogen selectivity towards CHO.
- The catalyst retained 91.8% of its initial efficiency after extended cycling, outperforming pristine BiPO4.
Conclusions:
- Bi(III) sites are critical for promoting the desired *NH2OH pathway, avoiding undesired side reactions.
- The amorphous SiOx acts as an electron buffer, stabilizing Bi(III) active sites.
- The stabilized Bi(III) site effectively suppresses competing hydrogen evolution and over-hydrogenation, enabling efficient CHO electrosynthesis.
Related Concept Videos
01:26Thermal and Photochemical Electrocyclic Reactions: Overview
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
01:17Thermal Electrocyclic Reactions: Stereochemistry
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
03:00Preparation of Epoxides
Overview
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
01:26Photochemical Electrocyclic Reactions: Stereochemistry
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Selection Rules: Photochemical Activation
01:18Benzene to 1,4-Cyclohexadiene: Birch Reduction Mechanism
Birch reduction uses solvated electrons as reducing agents. The reaction converts benzene to 1,4-cyclohexadiene. The reaction proceeds by the transfer of a single electron to the ring to form a benzene radical anion. This anion is highly basic—it abstracts a proton from the alcohol to form a cyclohexadienyl radical. Another single electron transfer gives the cyclohexadienyl anion. A proton transfer from the alcohol forms 1,4-cyclohexadiene. Since this reduction occurs via radical anion...
01:27Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation
Robinson annulation is a base-catalyzed reaction for the synthesis of 2-cyclohexenone derivatives from 1,3-dicarbonyl donors (such as cyclic diketones, β-ketoesters, or β-diketones) and α,β-unsaturated carbonyl acceptors. Named after Sir Robert Robinson, who discovered it, this reaction yields a six-membered ring with three new C–C bonds (two σ bonds and one π bond).