[RishabhChittoria]

i am searching for a liquid with boiling point below 100°c which is non flammable and could withstand heat
and high pressure without oxidizing

[Arkcon]

i am searching for a liquid with boiling point below 100°c

A good starting point, for solving this problem for yourself, would be to check the CRC.  Once you find some chemicals with the boiling point you want, you can check other references to see if they match the other properties you need.

which is non flammable

Something you can check in references once you have a shorter list than "everything"

and could withstand heat and high pressure

You will not get useful answers without qualifying these values better.  How much heat, for how long?  How much pressure?  Raising pressure raises boiling point, so if you raise pressure enough, you can reach a boiling point above 100 C.  In which case, you can just use a cheap solvent, called water.  Unless you can't for another reason.  You can also give us that reason.

without oxidizing

You can prevent oxidation with antioxidant additives, or use something that doesn't oxidize.  Or prevent oxygen from reaching it.  Unless you mean other thermal degradation.  Also, pressure may have no effect on oxidation, unless you mean pressurized air, or high temperature pressurized steam.

I hope you don't mind me answering questions with more questions.  But that's what we do here: its all in our Forum Rules{click}.  You agreed to these rules as a condition of signing up for our forum, and they apply to you, whether you agree with them or not, or even if you're unaware of them.