This behavior is incompatible with the reaction taking place in the bulk of the methanol-rich phase because in such phase there is no initial gradient of the methoxy ion as the methanol is in a large excess, the methoxy ion is not consumed and its initial concentration is homogeneous in the fed methanol;the only reason to generate a gradient in the methanol-rich bulk phase is as a result of mass transfer from the reaction zone towards the methanol-rich bulk phase that would
dilute the methoxy ion, but the formation of G from MG is small in the initial length of the reactor, as it can be deducted from Fig. 4