By disenchanting an items you get gold depending on its rarity.
Each rarity has its own disenchanting time and gold received:
Disenchanting a Common itme will take you 0.35s and reward with 12 gold.
Disenchanting a Rare item will take you 0.35s and reward with 24 gold.
Disenchanting an Epic item will take you 3s and reward with 36 gold.
Disenchanting a Legendary item will take you 5s and reward with 72 gold.