Controlled multistep synthesis in a three-phase droplet reactor

Abstract

Channel-fouling is a pervasive problem in continuous flow chemistry, causing poor product control and reactor failure. Droplet chemistry, in which the reaction mixture flows as discrete droplets inside an immiscible carrier liquid, prevents fouling by isolating the reaction from the channel walls. Unfortunately, the difficulty of controllably adding new reagents to an existing droplet stream has largely restricted droplet chemistry to simple reactions in which all reagents are supplied at the time of droplet formation. Here we describe an effective method for repeatedly adding controlled quantities of reagents to droplets. The reagents are injected into a multiphase fluid stream, comprising the carrier liquid, droplets of the reaction mixture and an inert gas that maintains a uniform droplet spacing and suppresses new droplet formation. The method, which is suited to many multistep reactions, is applied to a five-stage quantum dot synthesis wherein particle growth is sustained by repeatedly adding fresh feedstock.

Droplet Microfluidics as a Tool for the Generation of Granular Matters and Functional Emulsions

“…The limited volume of the droplet microreactors restricts their use in the classic and large-scale synthesis of common chemical compounds. The situation is different in the case of synthesis and formulation of fine and expensive chemicals such as nanocrystals and microcapsules for which droplet microfluidic have already proved to be a very promising alternative to classic technologies (Ekanem et al, 2017;Nightingale et al, 2014;Phillips et al, 2014). Further studies on the crystallization will be carried out and they might reflect on the fundamental knowledgee.g.…”

Droplet microfluidics: A tool for biology, chemistry and nanotechnology

“…Compared to continuous-flow chemistry where channel fouling could lead to poor product control and reactor failure, droplet chemistry prevents fouling by isolating the reaction from the channel walls [58]. Droplets can be used as chambers within which synthesis occurs; they can be used as a structure that directs agents to generate complex nanostructures [59] and they can be used to generate cell-like structures.…”

“…One major issue in complex synthesis is that multiple reaction steps are involved. New reagents often must be added to the droplet; this requirement can be met by the fusion of droplets containing the new reagents with the reaction droplet or by the injection of the new reagent into the reaction droplet [58] (Figure 4). However, in many cases material must be removed from the droplets, a step that cannot be achieved by washing but can only be done by splitting off part of the droplet.…”

A self-triggered picoinjector in microfluidics

“…6,7 To carry out complex experiments like these, it is important to add reagents to a droplet, and control the dosing volume and time. 8,9 Adding a precise amount of reagents into a droplet poses many difficulties. Various schemes for reagent addition have been investigated by researchers, which include: (1) Dosing of liquid reagents into droplets using a single T-junction.…”