Each of Job's friends are introduced with their tribe or clan's name. These names can pretty easily be matched up with individuals listed in the genealogies. It follows that Job cannot take place at least until these forefathers are born and have children. Here are the lineages of Job's friend:
Elihu, son of Barachel the Buzite:
Buz was the son of Nahor (Genesis 22:21), brother of Abram (Genesis 11:26), both sons of Terah.
Bildad the Shuhite:
Shuah was Abraham's son Keturah Genesis 25:2.
Eliphaz the Temanite:
Teman was the son of Eliphaz (Genesis 36:11), son of Esau (Genesis 36:4), makes sense that he would be named after a forefather.
Zophar the Naamathite:
Naaman was the son of Benjamin (Genesis 46:21), the youngest of the sons of Israel.
While Job is said to live in the land of Uz, (again, "where?" being just as much a mystery as "when?") there is a Job that shows up in the Genesis 46:13 as on e of the sons of Issachar, a son of Joseph.