Colin Berry: So how could Ray Rogers have got it so wrong?
To cite an everday example, you can quickly get bread to go golden-brown in an electric toaster (the classical Maillard browning reaction), but if your toaster was broken, then sitting bread on the lid of the electric kettle, and heating it to 100 degrees will not produce toast, no matter how long you wait – hours, days, weeks etc. Not even slightly toasted. The Maillard reaction is simply not THERMODYNAMICALLY FEASIBLE at 100 degrees Celsius, even if other chemical reactions are occuring at multiples of their normal room-temperature rate. Maillard reactions generally do not get going until the temperature is 150 degrees and above, and there are sound thermodynamic reasons for that which have nothing, I repeat NOTHING, to do with chemical kinetics, the latter being a separate subject from chemical thermodynamics, though interfacing with it as discussed later. Thermodynmaics is about whether reactions are feasible in principle, i.e. go of their own accord. Kinetics is about the rates of reaction that are feasible. Some feasible reactions will not proceed at measurable rate, due to a minuscule rate of reaction, but a non-feasible reaction will not respond to a modest rise in temperature unless that rise (improbably) brings it into the range of thermodynamic feasibility.
So how could Rogers have got it so wrong, despite his impressive, some might say impeccable credentials in the area of thermochemistry?
Didn’t Rogers write (and isn’t this a picture of success):
After these successful experiments, a sample of Edgerton’s bleached linen was placed on four drops of dextrin solution on a plastic plate. A round spot was obtained and the water was allowed to evaporate from the cloth: at this point no colour could be seen on either surface. The middle of the same sample was placed on four drops of Saponaria solution. The wet spot expanded radially through the cloth. The water was allowed to evaporate, and no colour could be observed. The sample was then treated for 10 minutes with ammonia vapour: a very light colour could be observed on the top surface after standing 24 hours at room temperature.