The preparation of di-2-ethylhexylphthalate (DOP) via esterification reaction of phthalic anhydride by 2-ethylhexanol in the presence of solid acidic catalysts has been investigated. The used catalysts were natural zeolite, synthetic zeolites (ZEOKAR-2, ASHNCH-3). heteropolyacid H4Si(W3O10)(4) and sulfated ZrO2. The reactions were carried out under solvent-less conditions, It was observed that sulfated ZrO2 has higher reactivity and efficiency among the investigated catalysts. In the next part of the work, important plastieizers and ester base oils have prepared through esterification reaction of anhydrides and acids by alcohols in the presence of sulfated Zirconia. (c) 2005 Elsevier B.V. All rights reserved.