Physical properties Residue curves

Table 8.1 describes the steps of the methodology in more detail. The procedure starts with the Problem definition production rate, chemistry, product specifications, safety, health and environmental constraints, physical properties, available technologies. Then, a first evaluation of feasibility is performed by an equilibrium design. This is based on a thermodynamic analysis that includes simultaneous chemical and physical equilibrium (CPE). The investigation can be done directly by computer simulation, or in a more systematic way by building a residue curve map (RCM), as explained in the Appendix A. This step will identify additional thermodynamic experiments necessary to consolidate the design decisions, mainly phase-equilibrium measurements. Limitations set by chemical equilibrium or by thermodynamic boundaries should be analyzed here. 

In contrast to other esterifications, a significant extent of reaction can be reached even without a catalyst though the reaction equilibrium constant is approximately one. A compilation of the major physical property data can be found elsewhere [25, 87]. Fig. 10.2 shows the residue curve map in transformed coordinates as introduced by Doherty and coworkers [108] at a pressure of 1.013 bar. Due to a single maximum azeotrope, there are two distillation regions. The concentration profile in a single feed, two product lab-scale column with 45 bubble cap trays is also displayed in Fig. 10.2. The column is fed with a stoichiometric feed of formic acid and methanol and operated at a reflux ratio of 5. Water and the desired methyl formate are recovered at purities of about 97 % molar concentration in the bottoms and at the top, respectively. 

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