Great Tang: Making Salt with Chemistry from the Start, Li Er Wants to Partner Up

A chemistry PhD is reborn in the Tang Dynasty. He has nothing but his brains and no System. See how the protagonist turns the Tang Dynasty upside down. He purifies salt, makes gunpowder, and uses bromide-induced addiction to control ambitious warlords, rewriting the Xuanwu Gate Incident with chemical equations! A conspiracy lurks behind the salt and iron struggle, while the Five Great Clans and Seven Noble Houses lay a deadly trap. Even Li Shimin has to call him "Sir"!