No she didnt. Demeter has a daughter named Persephone.
Plutus
Persephone, Despoina, Eubuleus, Arion, Plutus, Philomelus, Iacchus, Acheron, Hecate (Orphic)
Zeus is the son of Rhea and Cronus, his brothers and sisters are Hestia, Demeter, Hera, Poseidon, and Hades.
Demeter is a girl. Demeter was a Greek goddess of agriculture.
Triptolemus was not really a ruler. He was the son of King Celeus of Eleusis in Attica, and was one of the original priests of Demeter. He gained the knowledge of the Eleusinian mysteries.
Demophoon (more commonly translated as Demophon, but not to be confused with Demophon, King of Athens and son of Theseus) was the son of King Celeus and Queen Metanira. King Celeus offered hospitality to the goddess Demeter while she was in the guise of an old woman named Doso and searched for her daughter Persephone. King Celeus asked Demeter to nurse his sons, Demophoon and Triptolemus. In return for his generosity, Demeter offered to turn Demophoon into a god. While she was doing so by placing him in a fire to burn away his mortal soul, Queen Metanira happened upon them and screamed at seeing her child on fire. Demeter was angered that she was interrupted and the Queen Metanira did not understand the ritual. Instead of making Demophoon a god, Demeter taught Triptolemus agriculture and helped him to spread the knowledge across Greece.
Persephone, Despoina, Eubuleus, Arion, Plutus, Philomelus, Iacchus, Acheron, Hecate (Orphic)
I know of no instance where Demeter specifically granted immortality to a mortal. However, there is a very early myth that involves Demeter as the nurse for the sons of King Celeus of Eleusis. AS s gift for his hospitality, she planned to make his eldest son, Demephon, a god. Every night, she would coat his body in ambrosia, breath gently into his mouth as she held him close, then she would place him in the hearth to burn away his mortal soul. On the final night of the ritual, Metinara, the mother of the boys saw her son in the flames and removed him, admonishing Demeter for her carelessness. Demeter spat at the woman and said that her ignorance cost her more than she would ever know and she disappeared.
No she didnt. Demeter has a daughter named Persephone.
Plutus
Demeter became angry with Metaneira because she tried to initiate her son Demophoon into the mysteries of the goddess without her consent. This violated the sacred rituals and caused Demeter to reveal her true identity, leading to a conflict between them.
4600 Celeus
The name of Zeus and Demeter's son is Persephone, who is also known as the goddess of the harvest.
Iasion
Odysseus is said to be the son of Anticlia, daughter of Autolycus. Autolycus is a son of Hermes, Zeus is the father of Hermes. Demeter is the sister of Zeus.
I don't know but Demeter's daughter is Persephone.