b) Effect of OA:TMP molar ratio
For reversible reactions, an excess of a reactant drives the foreword
reaction generating more products to restore a new equilibrium point. In
the case of catalytic reversible reactions, where the reactants must
collide the catalyst active site on the same time, this concept is
limited to a certain excess reactant concentration. The increase of a
reactant concentration will dilute the other reactant and diminish the
probability to meet each other on the catalyst surface. This research
may confirm this concept where the catalytic performance was
investigated over the molar ratio of OA: TMP range from 3:1 to 5:1 at
fixed: temperature of 130oC, reaction time of 20h and
catalyst dosage of 3 wt.%. Figure 5, shows the increase of total
conversion with increase of OA/TMP molar ratio up to 4.5:1 to begin
dramatically decrease with further increase of OA/TMP molar ratio. The
same result was reported by Li et al (Li, 2012). It is noticeable that
the increase of OA/TMP has a significant effect on the increase of the
total conversion at the beginning and diminishes gradually till reaches
the minimal increase at 4.5:1. This result runs in harmony with the
previous concept.