A friend with a doctorate in chemistry sent me the following: "According to the official government story, TATP (triacetone triperoxide) was the explosive these conspirators were planning to manufacture aboard the airliners.
"This story is not plausible for a number of reasons:
TATP is made from hydrogen peroxide solution, acetone and sulfuric acid. Acid must be added, a drop at a time..this step of the process will take several hours, during which the fumes given off will be substantial and quite overpowering, thus a lab-quality air evacuation system is required.
"One then must let the resulting solution stand for an extended period at temperatures above the freezing point, but definitely below 10 Celsius (50 Fahrenheit). Above 10 Celsius, the TATP does not form; instead, diperoxide forms, which is so unstable it cannot be worked with. The time required for the reaction to go to completion is at least 24 hours and often several days.