Testing the Testing of Mogas

"Crash Lander" wrote

Not at all a scientific type person, so this may be a dumb question, but
is
there any way to evaporate the water out of the isopropyl alcohol without
burning off the alcohol, or is the evaporation point of the alcohol lower
than that of the water? If so, could you evaporate the alcohol out of the
water, and collect the pure alcohol that way?

Having been _around_ a "hobby still", I feel somewhat qualified to answer
this.

Alcohol boils at around 187 F.. Don't everyone give me grief. I know it
isn't exact, but it has been a while, and it is not important to this
discussion. Water boils at 212 F.. The alcohol will be gone first, if
heated, or allowed to evaporate.

What you need to do, is use a still, to heat the water and alcohol, and hold
the temperature at the coils at 187 F, until nothing is condensed from the
still's cooling coils. The percentage of alcohol (not the proof) will be at
best 98 percent. It takes some very good tricks to get the rest of the
water out, that will be out of reach for a hobby type of operation.

The only answer to get pure alcohol is from chemical supply houses. That
said, I doubt very much that the alcohol produced to blend with gas is above
98 percent pure. Anyone know, for sure? If it is not 100 percent, then
there we have it; the water in the fuel we need for the test. Back to
Jose's extra test steps, to find out how much water it takes to test
positive.
--
Jim in NC