A process for preparing alkyl-extended, alcohol-extended or amine-extended piperazines or mixtures thereof comprising contacting a difunctional aliphatic alcohol with a reactant amine, wherein at least one of the aliphatic alcohol or the reactant amine contains a piperazine moiety, in the presence of a catalyst containing a Group VB metal oxide or a Group VB metal phosphate, or mixtures thereof. For example, monoethanolamine reacts with piperazine in the presence of a catalyst of niobic acid supported on hydrated alumina to yield predominantly N-(2-aminoethyl)piperazine. Also, N-hydroxyethylpiperazine reacts with piperazine in the presence of a catalyst of niobium phosphate to yield predominantly 1,2-bis(piperazinyl)ethane.