Reactions of alcohols with carboxylic acids to form esters arefundamentally important in organic synthesis. Typically, theseesterication reactions require an acid catalyst to promote theelectrophilicity of the carbonyl moiety,1a with heating improvingthe kinetics.1b As chemistry has progressed, so has the diversityand complexity of such catalysts, with the ability to generateesters in excellent yields.2–6 Nevertheless, the inherentcomplexity, associated expense of such processing and thesafety of large scale batch processing can be questionable, ascan the difficulties in scaling up. To this end we have developedhigh yielding esterication reactions, where the chemistry issimplied, using continuous ow processing and simple acidcatalysts within the connements of the recently developedvortex uidic device (VFD).7 This thin lm microuidic platformallows the continuous ow processing of uids up to 7 mLmin1 or 20 mL min1 for the 7.0 mm or 17.5 mm internaldiameter borosilicate tubes (commercially available sizes ofNMR tubes) respectively, Fig. 1. Scaling up is possible by usingparallel arrays of such inexpensive VFD, as in conventionalmicrouidic processing involving channels. In this context,clogging is not an issue for the VFD, as it can be for othermicrouidic processing platforms.8Esterication reactions are widely used in industry,including the synthesis of alkyl-acetate based esters and fattyacid esters as in biodiesel production. Butyl acetate alone is animportant component in coatings, having a relatively lowvapour pressure, featuring as a solvent for polymerizationreactions and as a fragrance in cosmetics.9,10 Currently,advancing the production of esters (especially for biodiesel)focuses around microbial lipases and oleaginous microorganisms,11,12 with other processes using ion exchange resins13 andheterogeneous catalysts such as MgO14 and Na2CO3.15 Whilethese systems are highly effective, there is a number ofconcerns, including the generation of a waste stream, catalystlifetime, the use of high temperatures and pressures, and ratherspecic conditions required for biological catalysts. In addition,Lewis acid catalysts, for example, tin-octoate, require removalaer processing.9 Overall, developing more versatile and morebenign alternative reactions, using smaller amounts of catalystat standard temperature and pressure, with lower environmental impact and capital outlay are warranted.16,