Mafia 84. Memorized it, turned it in, forgot it!

Hexane is used in the extraction of vegetable oils and as an organic solvent.

No, hexane is a type of gasoline (one of its components, actually), and it's incompatible with cooking (it might be used in the food industry, but not in cooking).

Several Alex chefs at once. Any choice you want.

That doesn't work either, because Alex couldn't have been killing anyone that night, as he was in lockdown.

So far, no luck, but keep looking!