These pumps are very well suited for rotovaps, filtrations, distillations etc. The usual in use vacuum for the smaller one is about 12-15mbar, I have used that pump often for sassy distillation, rotovapping, vacuum isomerisation etc.
For ketone and product distillation I preferred an oil pump (with really old smelly oil which I never changed, another way to limit your vacuum
). The one rated for 2mbar should work well for that purpose too.
I once witnessed a distillation attempt of sassy using a 6L flask and a MZ2C, and it was not pretty. Lots of bumping. But that wasn't the pump's fault, you either need to use a capillary extending to the bottom of the flask for good mixing or overhead stirring. Magnetic stirring didn't work. The reason is that the oil overheated at the bottom of the flask, and when it reached the surface it vigorously boiled causing the horrible bumping.
Let's say you have 15mbar of vacuum in the vapor phase above the liquid and 20cm (8 inches)of oil in the flask. Then the pressure on the flask's bottom will be much higher, meaning the oil will overheat. Using the above numbers and assuming the oil has a density of 1.0 the pressure on the bottom of the flask will be about 35mbar (because of the liquid column's weight has to be added)! Without efficient stirring this hot overheated oil, when it eventually rises to the surface will explosively evaporate. Using a capillary will make sure that the vacuum is the same everywhere, and the introduced gas bubbles will sort of catalyse the evaporation/boiling.
Same happens during the vacuum isomerisation BTW, that's why I never did it big scale. A 2L flask worked well with magnetic stirring, bigger ones were bumping horribly.
I'm not fat just horizontally disproportionate.
