Processes for regenerating ionic liquid catalyst by contacting the ionic liquid catalyst with hydrogen gas in a regeneration reactor. The amount of hydrogen is less than 550 SCF/BBL (97.96 m3/m3) of spent ionic liquid catalyst, or less than 500 SCF/BBL (89.05 m3/m3) of spent ionic liquid catalyst, or between 550 and 45 SCF/BBL (97.96 and 8.015 m3/m3) of spent ionic liquid catalyst, or between 500 and 50 SCF/BBL (89.05 and 8.905 m3/m3) of spent ionic liquid catalyst. Alkylation processes are also disclosed.