This invention comprises a process and a system thereof comprising apparatuses for developing multi-component vapor mixture by heating of solution of reactants comprising one or more of diphenols, or diphenol derivatives, and an organic compound, wherein the organic compound is one which upon reacting in a vapor state in presence of a catalyst with diphenols, or diphenol derivatives, produces a monoalkyl ether of a dihydric phenolic compound; and wherein the entire solution of reactants completely transforms into a super-heated multi-component vapor using heaters without the use of thin film evaporator. The complete transformation of the entire solution of said reactants in to super-heated multicomponent vapor is achieved by heating the entire solution firstly by a pre-heater followed by further heating by a super-heater, further comprising removal of the condensed high boilers and tar to drain, and subjecting the superheated vapor to vapor phase reaction mediated by catalyst to get monoalkyl ether of a dihydric phenolic compound.