A process for reacting relatively small hydrophilic carboxylic molecules with relatively large, hydrophobic hydrocarbon based molecules, said process comprising conducting the reacting in the presence of a sulfonic acid catalyst having solubilizing properties. In a preferred embodiment the large hydrophobic molecule comprises at least one member of the group consisting of (1) olefinically unsaturated hydrocarbons containing at least about 10 carbon atoms and (2) aliphatic hydrocarbyl group substituted hydroxy aromatic compounds wherein the aliphatic hydrocarbyl group contains at least 12 carbon atoms and the small hydrophilic molecule comprises a carboxylic reactant selected from the group consisting of compounds of the formula R.sup.3C(O)(R.sup.4).sub.nC(O)OR.sup.5 wherein each of R.sup.3 and R.sup.5 is independently H or a hydrocarbyl group, R.sup.4 is a divalent hydrocarbylene group, and n is 0 or 1, and reactive sources thereof.