Fig. 4: Knoevenagel condensation controlled by an organic oscillator within the same CSTR.
From: A catalytically active oscillator made from small organic molecules
a, Reaction scheme for a catalytic reaction coupled to flow oscillations. b, Oscillation space predicted by the oscillator model in the absence of catalysis: the region coloured in a gradient from red to green indicates the ranges of [4] and [2] predicted to support sustained oscillations with [3] = 30 mM, [5] = 5 mM and a space velocity of 10−4 s−1; colour coding indicates the predicted period. In the light blue region, dampened oscillations are predicted to take place and in the uncoloured region no oscillations occur. Squares represent oscillator experiments carried out without catalysis, as in Fig. 3b; filled squares indicate where experiments found sustained oscillations and open squares dampened oscillations. Diamonds represent oscillator experiments carried out with catalysis; red diamonds indicate where experiments found sustained oscillations and white diamonds dampened oscillations. c, Flow experiment carried out in CSTR at 60 °C using [2] = 100 mM, [3] = 30 mM, [4] = 1.8 M, [5] = 5 mM, [8] = 200 mM and [9] = 200 mM in DMSO, with a space velocity of 10−4 s−1. Sustained oscillations are obtained for 6 (red), 8 (pink) and 10 (orange). The reported period is the mean with s.d. from a single experiment. d–i, The oscillation space was investigated by carrying out experiments with the following deviations from the conditions shown in c: d, [2] = 80 mM; e, [2] = 120 mM; f, [4] = 1.4 M; g, [4] = 2.2 M; h, 70 °C rather than 60 °C; i, 50 °C rather than 60 °C; j, flow experiment carried out in CSTR using the same method as in c, but after two pulses the system was perturbed by raising the temperature to 70 °C for 30 min (blue-shaded area).
