The role of para–meta isomerization in the selective synthesis of para-tert-butylphenol in the presence of modern macroporous sulfonic cation-exchange resins

Abstract

The formation of meta-tert-butylphenol (m-TBP), which decreasing the quality of the commercial product, is shown to be possible in the target synthesis of para-tert-butylphenol (p-TBP) in the presence of sulfonic cation-exchange resins using macroporous Amberlyst 36 Dry as an example. The equilibrium concentration of m-TBP in the liquid phase (the maximum value at 409 K is 47 wt %) is calculated from experimental and published data. Up to 10 wt % m-TBP (on the reaction mixture basis) is formed at the maximum values of temperature (409 K) and contact time (450 min). Kinetic characteristics are determined for the $p - TBP + phenol\underset{{{k_{ - 6}}}}{\overset{{{k_6}}}{\longleftrightarrow}}m - TBP$ + phenol reaction, which supplements the kinetic model for the production of p-TBP. The rate constants of this reaction are several orders of magnitude smaller than those for the main (ortho–para) transformations. The temperature range (353–383 K) and contact time at which the formation of m-TBP is minimum and exerts no effect on the qualitative characteristics of the target p-isomer are determined.