Phase-Transfer Catalysis 2D: Reaction-Diffusion Interfacial Shuttle

This is the 2D companion to the 3D interfacial-shuttle model of Starks' extraction mechanism. Instead of tracking individual particles bouncing inside an orbiting 3D box, this version solves the same catalytic cycle as a genuine 2D reaction-diffusion-advection field: an organic concentration field and an aqueous concentration field, stacked with a shared interface, coupled by a catalyst field that diffuses through both and is pushed across the interface by a constant extraction drift. Catalyst loading, stirring rate, anion lipophilicity and temperature drive the exact same rate constants as the 3D model — a diffusion coefficient, a vertical drift velocity, and an Arrhenius-scaled reaction rate — with live conversion, turnover-number and rate readouts computed directly from the field's own mass balance.