The synthesis of tertiary butyl alcohol (TBA) via isobutene (iB) hydration was studied over Amberlyst-15 sulfortic acid catalyst particles using pure water and aqueous TBA solutions in a bubbling slurry reactor. Preliminary studies to investigate mass transfer effects showed that pore diffusion was present for catalyst particles greater than 165 mum in diameter. Therefore, intrinsic kinetic measurements were made using 90.5 mum catalyst particles and a catalyst loading of 10 kg m(-3). The kinetic measurements revealed that iB hydration is a pseudo-first-order reaction with an activation energy of 69 kJ mol(-1). Isobutene hydration experiments using TBA concentrations in water revealed a hindering effect of TBA, which indicates that separation of TBA formed by iB hydration in three-phase reactors using catalytic distillation is promising from a process design perspective. (C) 2002 Elsevier Science B.V. All rights reserved.