A process for selectively making 2-alkenes from a NAO using a mesoporous catalyst that has been surface modified with a Bronsted acid compound. The Bronsted acid compound has a reactive silane connector, an organic linking group, and a Bronsted acid group. The mesoporous catalyst has an average pore diameter in a range of about 12 to about 100 Angstroms and a surface area of between about 400 to about 1400 m.sup.2/gram.