Józef Zawadzki (chemist)
Zawadzki was a co-founder, President and Vice-President of the Polskie Towarzystwo Chemiczne. He was a professor (from 1923) and rector (1936–1939) of Warsaw University of Technology, and a member of the Polish Academy of Learning (since 1947).
His main field of research was physicochemical fundamentals of chemical technology. He was researching contact oxidation of ammonia, naphthalene and anthracene, mechanism of ammonia oxidation on platinum at low temperatures, reduction of iron dioxide by a methane, methods of obtaining aluminium oxide from Polish kaolinite and aluminosilicate, use of Polish anhydrite and gypsum deposit to production sulfuric acid and cementum, kinematics of thermal dissociation.
Under the German occupation of Poland during World War II, he was involved in the clandestine operation of the Warsaw University of Technology. Together with Marceli Struszyński, Zawadzki analyzed captured German V-2 rocket for its fuel composition. In 1947, he was recognized with a Doctor Honoris Causa.
Mechanism of ammonia oxidation on platinum at low temperatures
The mechanism of ammonia oxidation on platinum at low temperature was postulated by F. Rachsig (1927) and later adapted by Zawadzki (1948, 1950) to proceed via formation on imide (NH). In this proposal formation of nitroxyl and hydrazine (N2H4) is involved:
- NH3 + O(a) → NH(a) + H2O
- NH(a) + O(a) → HNO(a) + *
- NH(a) + NH3 → N2H4(a)
- HNO(a) + NH3 → N2H4(a) + ½O2
- N2H4(a) + O2 → N2 + 2H2O + *
Later, Y. M. Fogel (1964) disproved the Zawadzki theory that NH is formed via the oxidation of ammonia. In his proposal, NO is an important intermediate of the reaction. The formation of N2O is not detected, therefore the mechanism does not involve its production.
- Technologia chemiczna nieorganiczna vol. 1–2 (1948–1949)
- Broek, Arnoldus Cornelis Maria van den (1998). Low temperature oxidation of ammonia over platinum and iridium catalysts (PDF). ISBN 90-386-0628-1.
- Sobczyk, Dariusz Piotr (2003). Positron emission profiling study of ammonia oxidation on platinum (PDF). ISBN 90-386-3034-4.
- "Zawadzki Józef". Internetowa encyklopedia PWN (in Polish). Wydawnictwo Naukowe PWN. Retrieved 2007-12-01.
- "Zawadzki Józef". WIEM Encyklopedia (in Polish). Retrieved 2007-12-01.