<p>Preparation of non-aromatic carbon-carbon double/triple bond compound (A) or its mixtures from another non-aromatic carbon-carbon double/triple bond compound (B), comprises reacting pure (B) with an adsorption agent comprising an aluminum oxide (3 wt.%) and activating at 450-1000[deg]C; and contacting the pure compound (B) with a metathesis catalyst.</p>
