A catalyst composition is disclosed. The composition comprises a titanium compound, a complexing agent, hypophosphorous acid or its metal salt, water and optionally a solvent. The complexing agent can be hydroxycarboxylic acid, alkanolamines, aminocarboxylic acids, or combinations of two or more thereof. The solvent can be water, ethanol, propanol, isopropanol, butanol, ethylene glycol, propylene glycol, isopropylene glycol, butylene glycol, 1-methyl propylene glycol, pentylene glycol, or combinations of two or more thereof. The titanium compound can be combined with a zirconium compound. Also disclosed is a process for using the composition for producing an ester or a polyester. The process comprises contacting a carbonyl compound, in the presence of the compositions, with an alcohol under a condition suitable for esterification, transesterification, polymerization, or combinations of two or more thereof.