Generally speaking, refluxing is used as a convenient means of controlling the temperature, since heating accelerates the rate of most chemical reactions by increasing the average kinetic energy of the molecules
These principle were first quantified by van't Hoff in 1884,
d ln
k/
dT =
Q/
RT2 The system you propose would bee inconvenient in practice, though of course possible
One would normally reflux the xylene to increase the reaction rate, though naturally, this could bee counterproductive in certain cases