A process which can be used in oligomerization, polymerization, or depolymerization such as, for example, the production of a polyester is provided. The process comprises contacting a carbonyl compound, in the presence of a composition, with an alcohol. The catalyst comprises a catalyst having the formula of M.sub.x Ti.sup.(III) Ti.sup.(IV).sub.y O.sub.(x+3+4y)/2 wherein M is an alkali metal, Ti.sup.(III) is titanium in the +3 oxidation state, Ti.sup.(IV) is titanium in the +4 oxidation state, x and y are numbers greater than or equal to zero wherein if x equals zero, y is a number less than 1/2.