Benzene and benzyl chloride produced from the reaction described in problem 3.6 are separated by distillation at 1 bar. The chlorine and HCl are removed easily and this problem concerns only a binary mixture. Suppose the liquid flow to the reboiler is 90 mol% chlorobenzene and 10 mol% benzene at 121.9°C. The boilup ratio is 0.7 at 127.8°C, and the vapor leaving the reboiler is 12.7 mol% benzene. The heat of vaporization of chlorobenzene is 41 kJ/mol. Heat capacities for liquids are in problem 3.6(a). Determine the heat duty for the reboiler.

Data from problem 3.6

Chlorobenzene_(l) is produced by reacting benzene_(l) initially at 30°C with Cl_2(g) initially at 30°C in a batch reactor using AlCl₃ as a catalyst. HCl_(g) is a by-product. During the course of the reaction, the temperature increases to 50°C. To avoid dichlorobenzenes, conversion of benzene is limited to 80%. On the basis of 1 mol of benzene, and 0.5 mol Cl_2(g) feed, what heating or cooling is required using the specified method(s)?

The NIST WebBook reports the heats of formation for liquid benzene and chlorobenzene as 49 kJ/mol and 11.5 kJ/mol, respectively. The heat capacities of liquid benzene and chlorobenzene are 136 J/mol-K and 150 J/mol-K, respectively. Use liquid reference states for the benzenes and the heat of reaction method for the energy balance.

Follow part (a), but instead, use the heat of formation method for the energy balance.

Use an ideal gas-phase reference state for the benzenes, Eqn. 2.45 to estimate the heat of vaporization, and the Heat of Reaction method.