Phthalic anhydride was esterified with n-heptyl, n-nonyl and n-undecyl alcs. in presence of H2SO4, H3PW12O40 center dot xH(2)O or TiBu4 catalysts (0.05-0.25% by mass) at 413 K to 453 K to det. the reaction kinetics. The 1st order reaction (except for TiBu4) was found. The TiBu4 showed the lowest catalytic activity but the highest activation energy (149,2 kJ/mole).