# Two‐Phase Epoxidations with Micellar Catalysts: Insights, Limitations, and Perspectives

## TL;DR

This paper explores using micellar catalysts in two-phase systems for epoxidation reactions, aiming to improve sustainability and catalyst recycling.

## Contribution

The paper highlights the use of surface-active catalysts and stimuli-responsive surfactants to address challenges in biphasic oxidation reactions.

## Key findings

- Biphasic epoxidations using micellar catalysts allow the use of hydrogen peroxide as a green oxidant.
- Mass transport limitations and side reactions remain significant challenges in biphasic systems.
- Tailor-made surfactants could enable controlled phase separation and more sustainable catalytic systems.

## Abstract

Biphasic molecular catalysis is a promising strategy for combining catalyst recycling with the synthesis of advanced chemical products. The anchoring of catalysts to surfactants in water allows for both catalyst solubility in aqueous media and a simple separation from the organic product. In biphasic epoxidations, this approach allows the use of environmentally benign hydrogen peroxide as oxidant. However, challenges remain due to mass transport limitations between the aqueous and organic phase, incompatibilities in the multicomponent system, and side reactions in the acidic medium. Hence, the development of surface‐active catalysts that enable controlled phase separation from all other components is highlighted in this concept article.

Biphasic phase‐transfer catalysis is a promising strategy for catalyst recycling, which has successfully been applied to various industrial‐scale reactions. Its extension to oxidation reactions is, however, challenging. This concept article discusses epoxidations in water using surface‐active catalysts and emphasizes potential pathways toward more sustainable catalytic systems by using tailor‐made, multitasking stimuli‐responsive surfactants.© 2025 WILEY‐VCH GmbH