| Late last evening I received an e-mail from a colleague affiliated with the University of Southern California. Professor Haiges informed those of us on the distribution that 1994 Nobel Prize in Chemistry Laureate, Dr. George Olah, had been called home. Here is the link to the obituary (https://www.nytimes.com/2017/03/12/science/george-olah-dead-nobel-prize-in-chemistry.html?_r=0) that appeared in The New York Times. |
| Apparently, Dr. Olah passed away last Wednesday. I was on travel and I was grappling with getting my laptop to work via something more than an ethernet connection (fortunately my hotel had more than just WiFi). Windows 10 continues to give my IT guru and me a difficult time. Had I known at the time of Dr. Olah's passing, I would have been stopped in my tracks. |
| Much more importantly, Dr. Olah's honored work was on super-acids. He had discovered the unique properties of antimony pentafluoride and how these unique properties could be exploited in carbocation chemistry. My encounter with Dr. Olah's scholarly work was much more mundane. |
| When I was still working for wages, I was confronted with an unknown corrosion issue at the plant where I had been working. Our process gas stream contained a mix of gases with very nearly the same molecular mass. The two most important of these were FREON-114 (C2F4Cl2) and pertechnetyl fluoride (TcO3F). The molecular mass of the CFC coolant was 171 units and the molecular mass of the technetium-containing compound was 166 units. Since the process gas stream flow was governed by Graham's Law of Effusion, the movement of the gases in the process gases stream was inversely proportional to the square root of the molecular mass of each gas in the process gas stream. With the square root of these molecular mass numbers being about 13, people much smarter than me could track these gases and know that they would effectively track together in the process gas stream. |
| At some point, severe corrosion was identified where the coolant and the technetium-containing compound had tracked. While the latter compound is radioactive, it was not known to be a highly corrosive gas. My task was to identify some compound of approximately the same molecular mass as the coolant and the technetium-containing compound that could be corrosive. When an infrared sample had displayed an unknown transmittance peak, further checking enabled the identification of arsenic pentafluoride (AsF5). The molecular mass of arsenic pentafluoride is 170 units. |
| A look at the periodic table confirmed my worst suspicions, arsenic is directly above antimony in the periodic table. Being familiar with Dr. Olah's seminal work (when he was at The Case Institute/Western Reserve University in Cleveland) on superacids, I had done "the music part" of the problem (deducing the underlying chemistry), "the lyrics part" (how did it get there) became the next battle/challenge. It turned out that the ore for the batch in question (that is fluorinated before it arrives as feed material) had an unusual amount arsenic oxide (probably As2O3 and As2O5) in it. |
| After repairing the corroded equipment, we updated the feed specification to limit the amount of arsenic in it. This corrosion problem then disappeared as quickly as it appeared. And the ultimate credit that for the solution to this challenging operations problem is owed to Dr. Olah (for his seminal work on the antimony analogs) and to Professor Mendeleev for the arrangement of the elements in the periodic table! |
| David M. Manuta, Ph.D., FAIC |
| President, Manuta Chemical Consulting, Inc. |
| March 15, 2017 |
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