Methylation variables affecting rate

The temperature dependence follows the Arrhenius equation and the reaction is usually carried out below 200 °C. The ratio of methanol/methyl acetate affects the overall reaction rate. With an increasing proportion of methanol, the space-time yield (g/L-h) increases (Figure 7). Therefore, the variability of the process in continuous operation is limited to certain acetic acid/acetic anhydride production ratios. 

The kinetics of the reaction of solid sodium iodide with 1-bromooctane were studied with a 95 % RS graft of polyethylene oxide) 6-mer methyl ether on 3 % CL polystyrene as catalyst (51)176). The rates were approximately first order in 1-bromooctane and independent of the amount of excess sodium iodide. The rates varied with the amount of the solid catalyst used, but there was not enough data to establish the exact functional dependence. All experiments employed powdered sodium iodide, magnetic stirring, and 75-150 pm catalyst beads. Thus the variables stirring speed and particle size, which normally are affected by mass transfer and intraparticle diffusion, were not studied. Yanagida 177) favors a mechanism of transfer of the sodium iodide by dissolution in the solvent (benzene) and diffusion to the catalyst particle... 

---