Global Climate Research

Overview

Microdroplet chemistry studies how confined liquid droplets change reaction rates and selectivity relative to bulk solution. Understanding and controlling these effects can enable novel, energy-efficient synthetic transformations.

Microdroplet chemistry exploits reactions in micron-scale liquid droplets where interfacial effects, concentration, and electric fields can accelerate or change reaction pathways. Supramolecular assembly and molecular recognition within confined microenvironments can alter accessibility of functional groups and thereby influence chemoselectivity.

The study addresses how supramolecular self-assembly in sprayed microdroplets can be used to control chemoselectivity during transformations of multifunctional biomass-derived molecules. Here we show that hydrogen-bonding-driven supramolecular assembly of 5‑HMF in sprayed microdroplets selectively shields carbonyl and hydroxyl groups while exposing the furan ring, enabling catalyst-free, ambient-temperature hydrogenation.

Prior work showed reaction acceleration in microdroplets but offered limited control over chemoselectivity and typically relied on catalysts or bulk-phase methods. Here, the authors demonstrate that intrinsic molecular recognition (hydrogen bonding) can direct site-selective reactivity in droplets without external reductants or metals, revealing a noncatalytic route to selectivity not previously established. Selective, catalyst-free transformations of biomass-derived molecules could reduce reliance on scarce metals and lower energy inputs in chemical manufacturing. Demonstrating control of chemoselectivity in microdroplets opens new sustainable pathways for valorizing platform molecules like 5‑HMF.

The approach may enable sustainable, metal-free upgrading of biomass feedstocks to value-added chemicals under mild conditions. It could be implemented in spray or microdroplet reactors for selective synthesis and guide molecular design to exploit self-assembly for chemoselectivity. Future work should expand substrate scope and quantify product yields and selectivity in continuous spray reactors, investigate detailed kinetics and the role of interfacial electric fields, and develop scalable droplet collection and product isolation methods.