A special case of alcohol dehydration is a reaction called the pinacol rearrangement. A molecule called pinacol, a diol (a molecule with two OH groups) is heated in the presence of sulfuric acid. The mechanistic steps are the same as you have seen for alcohol dehydration. The product, pinacolone, features a new C-O π bond rather than the new C-C π bond that is usually formed in alcohol dehydration.