def METHOD_NAME(self):
    self.reaction_rate = Var(
        self.params.rate_reaction_idx,
        initialize=0,
        doc="Rate of reaction [mol/m^3.s]",
        units=units.mol / units.m**3 / units.s,
    )
    try:
        def rate_rule(b, r):
            return b.reaction_rate[r] == (
                b.k_rxn
                * b.conc_mol_comp_ref["EthylAcetate"]
                * b.conc_mol_comp_ref["NaOH"]
            )
        self.rate_expression = Constraint(
            self.params.rate_reaction_idx, rule=rate_rule
        )
    except AttributeError:
        # If constraint fails, clean up so that DAE can try again later
        self.del_component(self.reaction_rate)
        self.del_component(self.rate_expression)
        raise