Processes for preparing a xylylenediamine by continuous hydrogenation, wherein the processes comprise: introducing a liquid circulation stream comprising a phthalonitrile and ammonia into a reactor to continuously hydrogenate the phthalonitrile in the presence of a heterogenous catalyst and the ammonia such that a reactor effluent comprising the xylylenediamine is formed; drawing off a portion of the reactor effluent to provide a first recycle stream; mixing at least a portion of the first recycle stream in a mixing unit with liquid ammonia and fresh phthalonitrile in solid or molten form to provide a second recycle stream; and recycling the second recycle stream to the liquid circulation stream, or wherein the second recycle stream and any remaining unmixed portion of the first recycle stream are both recycled to the liquid circulation stream.