[Pierre]

Hello,
I'm a student working on dilution and evaporation refrigerators and I'm having some trouble on my diethy lether refrigerator because I used silicone joints to make it liquidproof but I'm wondering if silicone is soluble in diethy lether as I discovered last week that plexiglass were soluble in ether  . If someone could help me with these experimental issues it would be nice.
Merci

[phth]

Be careful when handling toxic and explosive things.  Lots of plastics are partially soluble in ether.  Ether is the best choice to remove silicone gel/oil.  Look at the structure: can you tell why?

[discodermolide]

The use of diethyl ether in this sort of application is an extreme safety hazard and I can only strongly suggest you do not do this.
You have already noted a problem: imagine if the ether vapour had escaped through the leaky seal. One spark and BANG.
So investigate a different coolant.

[Enthalpy]

A tiny list of compounds and their boiling point:
http://www.engineeringtoolbox.com/boiling-points-fluids-gases-d_155.html
In the "Handbook of Chemistry and Physics" you find
Physical Constants of Organic Compounds > Boiling Point Index of Organic Compounds (= by temperature)
Fluid Properties > Thermophysical Properties of Fluids (=by molecule)
and > Critical Constants, Boiling Points etc
and > Physical Properties of Fluorocarbon Refrigerants

Any liquid that boils so easily and can burn is a huge fire and explosion hazard. Better avoid it. On the other hand, nonflammable liquids aren't so common and most of them are unhealthy like CCl₄. You best bet is a perfluorocarbon - they were developed for it, and as far as I know, the ones without Cl, Br nor Iodine are still permitted. For instance perfuoropentane C₅F₁₂ boils at +28°C
https://en.wikipedia.org/wiki/Perflenapent
please check the Material Safety Data Sheet (MSDS) by yourself.

To some extent, a different pressure changes a compound's boiling point, but said pressure can be inconvenient.

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For the resistence of polymers to solvents, what you need is a "compatibility list". Google it together with the name of the polymer (distinguish the molecule, the commercial name and so on, like PMMA for plexiglass) and of the aggressor like "diethyl ether".

Yes, ether dissolves quite a few polymers, and Pmma isn't very resistent to solvents. Silicone (usually dimethylsiloxane) is chemically much more inert but has some drawbacks too. Perfluorocarbons are very kind with most polymers.