More food for thought:
Source:
http://skunkpharmresearch.com/bho-extraction/
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Posted by
Skunk Pharm Research,LLC on
January 21, 2013 at 8:56 AM
The word Silicone covers a range of manmade polymers, based on a silica backbone, with carbon, hydrogen, oxygen, and other atoms bonded at the atomic level. It is used in oil and grease, silicone rubber, silicone resins, silicone caulking, adhesives, etc.
We may be talking semantics and word usage with the Cole-Palmer compatibility charts, as they are soaking mostly gasket materials in different solutions, to observe weight gain, loss, and change of physical appearance.
The polymers don’t all react the same to n-butane, and another issue Cole Palmer would have against using a silicone gasket material, is its gas permeability. It is about 400 times more permeable than butyl rubber, so while it is super for medical applications requiring aeration, it stinks for a gas tight seal.
A silicone resin spray, doesn’t care about gas permeability, and the n-Butane molecule has full valence orbit, it is not likely to react with the highly inert Silicone resin. Neither appears to be reactive enough to start or support a reaction at the temperatures involved.
I would be more concerned about PTFE finding its way into my heated oil, because even though it has a combustion temperature that starts decomposing it as low as 200C/392F (163C/325F?), if you read the fine print of the following two links, you will note the following issues, amongst them HF acid as a pyrolysis byproduct:
http://msds.dupont.com/msds/pdfs/EN/PEN_09004a2f806ab36e.pdf
http://en.wikipedia.org/wiki/Polytetrafluoroethylene
Acute inhalation toxicity: The thermal decomposition vapours of fluorinated polymers may cause polymer fume fever with flu-like symptoms in humans, especially when smoking contaminated tobacco.
The pyrolysis of PTFE is detectable at 200 °C (392 °F), and it evolves several fluorocarbon gases[21] and a sublimate. An animal study conducted in 1955 concluded that it is unlikely that these products would be generated in amounts significant to health at temperatures below 250 °C (482 °F).[22] More recently, however, a study documented birds having been killed by these decomposition products at202 °C (396 °F), with unconfirmed reports of bird deaths as a result of non-stick cookware heated to as little as 163 °C (325 °F).[21][23]
While PTFE is stable and nontoxic, it begins to deteriorate after the temperature of cookware reaches about 533 K (260 °C; 500 °F), and decomposes above 623 K (350 °C; 662 °F).[24] These degradation by-products can be lethal to birds, and can cause flu-like symptoms in humans.[24] In May, 2003, the environmental research and advocacy organization Environmental Working Group filed a 14-page brief with the U.S. Consumer Product Safety Commission petitioning for a rule requiring that cookware and heated appliances bearing non-stick coatings carry a label warning of hazards to people and to birds.[25]
Meat is usually fried between 400 and 450 °F (204 and 232 °C), and most oils will start to smoke before a temperature of 500 °F (260 °C)is reached, but there are at least two cooking oils (refined safflower oil and avocado oil) that have a higher smoke point than 500 °F(260 °C). Empty cookware can also exceed this temperature upon heating.
[edit]PFOA
Perfluorooctanoic acid (PFOA or C8) has been linked to cancer, thyroid disease, ulcerative colitis, and high cholesterol.[26] In the form of an ammonium salt,[27] it is used as a surfactant in the emulsion polymerization of PTFE,[28] [29] and has been detected in some PTFE products. [30][31] The levels that have been measured in nonstick cookware range from not detectable to 75 parts per billion.[31] [32] These are lower than in PTFE products such as thread sealant tape (with 1800 parts per billion (1.8 parts per million) of PFOA detected) because nonstick cookware is heated to volatilize PFOA.[30]
A DuPont study on Teflon PTFE did not detect any PFOA above their detection limit of 9 parts per billion,[33] and DuPont says no PFOA is in Teflon brand cookware.[34] A 2009 USEPA study found levels of PFOA in nonstick cookware ranging from undetected (with a detection limit of 1.5 parts per billion) to 4.3 parts per billion.[31] DuPont says there should be no measurable amount on a finished pan provided it has been properly cured.[35] While PFOA has been detected in the low parts per billion range in the blood of people,[36]exposure from nonstick cookware is considered insignificant[37][38] —despite the marketing of other wares. However, at temperatures well above those encountered in cooking,[39] PTFE pyrolysis can form minor amounts of PFOA.[40][41]
In January 2006, DuPont, the only company that manufactures PFOA in the US, agreed to eliminate releases of the chemical from its manufacturing plants by 2015,[42] but did not commit to completely phasing out its use of the chemical. In the emulsion polymerization of PTFE, 3M subsidiary Dyneon has developed a replacement emulsifier[43] despite DuPont stating that PFOA is an “essential processing aid”.[44] As of August 2008, the EPA’s position was that it “has no information that routine use of household or other products using fluoropolymers, such as nonstick cookware or all weather clothing, poses a concern.”[45]
GW"
So even even though Teflon/PTFE is a good choice in terms of it's non-reactivity to Butane, it can still be a problem if the coating comes off in your oil.
