do you really need one with pentane?
(vac pump).
@Lost710 what do you have for cooling, and vacuum on your rotovap?
you don’t want much heat, or much vac, you want plenty of cold, and ideally you’re using an aspirator style vac pump, or some other form of explosion proof pump.
Cold trap is critical if you’re doing something stupid like running any old vac pump.
you’ll also need a controlled leak to get your vac level right.
you can get away without a vac pump, depending on what your goals/next steps are (think “passive recovery” use cold as the driver, not heat).
Do you understand the Antoine equation?
see if you can find data for pentane and understand what vac depth is doing for this particular solvent.
check out Pentane - Thermophysical Properties for numbers to plug in.