strong O1 2' and a weak OH" ligand in the axial direction and that the strong O2" ligand is preferable to the 5 = 1 spin state of the central metal ion.

The ultimate objective of this work is to devise an accelerated test to compare rates of soluble gum and deposit formation from jet turbine and diesel fuels in storage and of hard deposits on hot engine parts. This paper describes rates of oxygen absorption and gum formation in air at 130 "C. For a single fuel or hydrocarbon, the rate of gum formation is closely proportional to the oxygen absorbed, even when this rate varies with purification and additives. In general, pure hydrocarbons absorb oxygen much faster than the fuels, but the fuels and 2-ethylnaphthalene give more gum for the oxygen absorbed than the other pure hydrocarbons. Gum has two main sources. One appears to be associated with the chain termination mechanism in oxidation, the other with coupling of fuel molecules by peroxides in the absence of oxygen. Other possibilities are discussed.

No abstract

Rates of oxidation and gum formation for six hydrocarbons, three jet turbine fuels and three diesel fuels have been measured at 100 °C in the presence of f-Bu202 as initiator. Four of the six fuels oxidize faster at 100 °C than in previous work at 130 °C without initiator. For any single substrate, the amount of gum produced for the oxygen absorbed is similar at 100 and 130 °C, even with large changes in rates and t-Bu202 concentrations. Thus, one mechanism of gum formation is intimately associated with oxidation. The effects of f-Bu202 concentration on the rates of oxygen absorption and gum formation show that gum formation is associated with chain termination by two peroxy radicals. In general, the pure hydrocarbons have long kinetic chains and give good yields of hydroperoxides. The fuels give short kinetic chains and produce little hydroperoxide but much gum for the oxygen absorbed. Another mechanism of gum formation is the coupling of substrates by peroxides in the absence of oxygen. The mechanism, condensation of oxidation products from alkylnaphthalenes, is also proposed.

Persalpetersäure wird durch Umsetzung von HNO3 (70%) oder NO2BF4 mit 90% H2O2 (entweder mit der reinen Flüssigkeit oder in MeCN‐Lösung) dargestellt, wobei die gasförmige Persäure durch einen Ar‐Strom aus dem Reaktionsgemisch abgetrennt und IR‐spektroskopisch identifiziert wird.