Abstract
Pure coconut oil, lanolin, and acetaminophen were vaporized at rates of 1–50 mg/min, using a porous network exhibiting a temperature gradient from 5000 to 5500 K/mm, without incurring noticeable chemical changes due to combustion, oxidation, or other thermally-induced chemical structural changes. The newly coined term “ereptiospiration” is used here to describe this combination of thermal transpiration at high temperature gradients since the process can force the creation of thermal aerosols by rapid heating in a localized zone. Experimental data were generated for these materials using two different supports for metering the materials to the battery powered coil: namely, a stainless steel fiber bundle and a 3-D printed steel cartridge. Heating coconut oil, lanolin, or acetaminophen in a beaker to lower temperatures than those achieved at the surface of the coil showed noticeable and rapid degradation in the samples, while visual and olfactory observations for ereptiospiration showed no noticeable degradation in lanolin and coconut oil while HPLC chromatograms along with visual observation confirm that within the limit of detection, acetaminophen remains chemically unaltered by ereptiospiration.
Highlights
Recent advances in scanning calorimetry have expanded the ability to take thermal property measurements of compounds that decompose at temperatures lower than the threshold values for melting or vaporization
Previous thinking that vaporization of pure labile compounds would not be possible did not consider the possibilities of rapid heating suggested by the above mentioned chip-based calorimeters, thermal aerosols made by rapid heating (0.5 s) of a thin film [6], or by the new fast vaporization method described here as “ereptiospiration” which is a combination of the latin words ereptio for “forcible taking” and spirare for “to breathe”
Experiments based on using a stainless steel fiber bundle and a 3-D printed steel structure containing pores illustrate how the process, called ereptiospiration, combines thermal transpiration with rapid heating in order to vaporize thermally labile materials before degradation is observed to occur
Summary
Recent advances in scanning calorimetry have expanded the ability to take thermal property measurements of compounds that decompose at temperatures lower than the threshold values for melting or vaporization. Ultra-fast differential scanning and fast scanning chip calorimeters have demonstrated very rapid heating rates [1] on the order of several thousand Kelvin per second, and the chip-based platform can conduct an entire measurement for a particular sample within a fraction of a second, yielding information on the reversible conversion of beta-pleated crystal structures of silk fibroin to random coils and helices [2] as well as the determination of ionic liquid vaporization enthalpies [3] Given these practical demonstrations of the principle that decomposition has finite kinetics, if temperature-induced physical changes occur rapidly enough, some compounds that are currently considered to be too labile for vaporization may be amenable to vaporization if a suitable, rapid means of heating is used. Previous thinking that vaporization of pure labile compounds would not be possible did not consider the possibilities of rapid heating suggested by the above mentioned chip-based calorimeters, thermal aerosols made by rapid heating (0.5 s) of a thin film [6], or by the new fast vaporization method described here as “ereptiospiration” which is a combination of the latin words ereptio for “forcible taking” and spirare for “to breathe”
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