Chemical Engineering Kinetics of Alkynol Syntheses

The alkynol syntheses (acetylen-formaldehyde) over three different catalysts at 95 to 110°C were investigated with formalin solution (5 to 25wt%), its flow rate being 1 to 5.5m3/m2·hr (space velocity of 0.5-2.0hr-1). The experimental data are discussed and analysed by means of the Hurt's "Height of Reaction Unit (Hr)" concept. Hr, defined by expression Hr=Z/ln(y1-y*/y2-y*), where Z the catalyst bed depth, y the concentration of the reactant at any point in the liquid stream, y* the equilibrium concentration of the reactant, is shown by plotting the results to be a linear function of the liquid flow rate at a constant temperature and feed concentration. From a consideration of the Arrhenius equation, it is shown that Hr should be approximately linear function of 1/T for a constant flow rate. This relation is found experimentally to hold for the range studied. For this reaction, the rate-controlling step is the surface reaction. As the results, the experimental correlations between Hr and reaction conditions are obtained, and an example of reactor design is presented.