Re: Is Flourine Ether a better substitute for CFC's in coolants.

There are a few difficulties with your question.

Firstly, unless you were lucky to stumble across a very generous scientist 
working on this exact problem, it is unlikely that you could get accurate 
and up to date information with an "are there other companies or 
universities involved..." type of question. You must try (1) a web search
(2) a "Chemical Abstracts" search (paper or electronic). You can do these 
searches as easily and as well as an "expert". Even if these fail, you 
cannot be sure that no-one else is working in the area, because this sort 
of development work with commercial applications in mind is often carried 
out fairly secretly for reasons of competitive advantage, especially if it 
is looking likely to be successful.

Secondly, "fluorine ether" (I presume you did not really mean flourine -- a 
by-product of wheat processing ;-) is not a recognised name of any 
particular compound. I think what you mean is bis trifluoromethyl ether, or 
hexafluorodimethyl ether: CF3OCF3, but I am not at all sure.

Instead of tackling the "who else is interested" question that you raise, I 
will provide a few general thoughts about whether such a compound is likely 
to be a better coolant than CFCs (the question in your title).

The operation of a coolant relies on heat removal associated with 
evaporation in the cool compartment, followed by condensation and 
associated heat release outside the cool compartment. So the primary 
requirement is for a substance with a convenient boiling point for this 
purpose. The operating temperature (depending on the exact application) is 
typically between about -30 deg C and 0 deg C; the convenient pressure 
range to work in is between about one tenth of an atmosphere and 5 
atmospheres, with higher pressures giving a greater cooling capacity. The 
bottom line is that we are looking for substances with normal boiling 
points between about -60 deg C and 0 deg C. We are also better off with a 
substance that has a high latent heat of vaporization and a high specific 
heat. All of the actual performance requirements rest on physical 
properties; so far there is no chemistry.

Where chemistry comes in is in the secondary requirements. In the early 
days the refrigerants investigated were things like ammonia, sulfur 
dioxide, methyl chloride, and propane. Although cooling systems are 
designed to work with a closed coolant loop, there are always accidents and 
leakages, and some of these proved quite unpleasant. Ammonia is very toxic 
and pungent, and although it is only marginally flammable, ammonia 
realeases in coolant leakages were sometimes associated with fires and even 
explosions. Sulfur dioxide is also extremely toxic and pungent, and in the 
presence of water it is quite corrosive to boot! Methyl chloride is quite 
toxic. It is less toxic than ammonia or sulfur dioxide, but more insidious 
because it is almost odourless. You can get quite a dangerously large 
exposure and be quite unaware of it. Propane is extremely flammable, 
besides being a fairly inefficient coolant because of a low latent heat of 
vaporization. So there are very serious secondary requirements: the ideal 
refrigerant should be non-toxic, non-corrosive, and non-flammable.

So when the first CFC: dichlorodifluoromethane -- CF2Cl2 -- was developed, 
it seemed to be an ideal solution. It was totally non-flammable and non-
corrosive, and had an extraordinarily low toxicity. The original toxicity 
testing makes interesting, if rather bizarre reading, if you can get hold 
of Midgley & Henne, Industrial & Engineering Chemistry, 22(1930), 543-544. 
But it achieved these results by being almost totally unreactive. It was 
not until nearly half a century later that we became aware of the 
unfortunate side effects of this unreactivity: CF2Cl2 slowly accumulated in 
the lower atmosphere, where it was almost indestructible, and eventually 
diffused to the stratosphere. There it was exposed to short wavelength UV, 
which decomposed it, and greatly increased the rate of ozone removal in the 
stratosphere.

The upshot is that there are now tertiary requirements for coolants: they 
must not deliver any chlorine (or bromine or iodine) to the stratosphere. 
Interestingly, fluorine does not matter.

CF3OCF3 has good potential as a coolant (I am only presuming that it has a 
suitable boiling point). It does not contain any chlorine. It is certainly 
not flammable. Much depends on its toxicity. Most fluorine compounds are 
very toxic. This compound falls into the class of very unreactive fluorine 
compounds that may not be. When considering toxicity, there is also a need 
to look at the toxicity of environmental or biochemical degradation 
products. Some of the HCFCs that have been recommended as replacements for 
CFCs raise a question because of a possible propensity to degrade into 
substances which include HF and CF3COOH, both of which are extremely toxic. 
On the face of it, neither of these notorious products is likely from 
CF3OCF3.