You don't even need to take a separate liquid. Here is one example of a flight turning around due to a horrible smell.
https://www.vice.com/en_us/article/bnpevw/one-year-on-still-thinking-about-poo-plane-303. Here is another example, in which the man who was the source of the smell (necrotic tissue from an infection that happened while he was on vacation) later died. http://www.foxnews.com/travel/2018/06/27/unbearable-smelling-passenger-that-caused-plane-s-emergency-landing-dies-from-tissue-necrosis.html. There is also a SpiceJet incident similar to the first (British Airways) one.
But if one were intent on taking a liquid onboard to contaminate the air, yes, it would be possible, and there are certainly many extremely foul smelling or even toxic liquids that would evaporate if spread broadly enough. Fortunately, the toxic compounds are difficult to obtain.
The air volume of a 747 is roughly 1,000 cubic meters. (Other planes are much smaller, so easier to contaminate.) When 100 ml of a liquid vaporizes, its volume depends on its density, temperature, pressure, and molecular weight. The vaporized volumes of 100 ml of trimethyl amine, cadaverine, putrescine, or various sulfides would be within an order of magnitude of 10 liters, and 10 liters is 1 part in 1 million of 1,000 cubic meters. Any of those would likely be foul smelling enough to require turning the plane around. (It might be easier to just bring some rotting fish, though.)
Cabin air filters and the ventilation system would gradually reduce the concentration somewhat, but if they were truly effective, those example flights wouldn't have been cut short. Ten passes through the system at 50% dilution per pass would reduce the original concentration by a factor of approximately 1,000, but that will take a while, and there are many compounds that stink even at 1 part in a billion. (And once dozens of passengers have vomited, that will add butyric acid smell to the mix.)
If anyone figures out you brought the stench onboard, you probably risk being beaten and certainly prosecuted. So yes, it's probably possible, but so far seems never to have occurred.