Tetrahydrofurans, from hydrocarbon oxidation

Apart from the conversion of peroxides to useful products, it is sometimes necessary to reduce peroxides, and especially hydroperoxides formed by auto-oxidation. Such compounds are formed especially in hydrocarbons containing branched chains, double bonds or aromatic rings, and in ethers such as diethyl ether, diisopropyl ether, tetrahydrofuran, dioxane, etc. Since most peroxidic compounds decompose violently at higher temperatures and could cause explosion and fire it is necessary to remove them from liquids they contaminate. Water-immiscible liquids can be stripped of peroxides by shaking with an aqueous solution of sodium sulfite or ferrous sulfate. A simple and efficient way of removing peroxides is treatment of the contaminated compounds with 0.4 nm molecular sieves [669]. 

The [Ruv(N40)(0)]2+ complex is shown to oxidize a variety of organic substrates such as alcohols, alkenes, THF, and saturated hydrocarbons, which follows a second-order kinetics with rate = MRu(V)][substrate] (142). The oxidation reaction is accompanied by a concomitant reduction of [Ruv(N40)(0)]2+ to [RuIII(N40)(0H2)]2+. The mechanism of C—H bond oxidation by this Ru(V) complex has also been investigated. The C—H bond kinetic isotope effects for the oxidation of cyclohexane, tetrahydrofuran, propan-2-ol, and benzyl alcohol are 5.3 0.6, 6.0 0.7, 5.3 0.5, and 5.9 0.5, respectively. A mechanism involving a linear [Ru=0"H"-R] transition state has been suggested for the oxidation of C—H bonds. Since a linear free-energy relationship between log(rate constant) and the ionization potential of alcohols is observed, facilitation by charge transfer from the C—H bond to the Ru=0 moiety is suggested for the oxidation. 

A nionic telomerizations of conjugated diolefins with hydrocarbon acids - are known but suffer from very low catalytic efficiencies. Morton et al. (I) and, later, Pappas et al. (2) used unchelated organosodium compounds to telomerize conjugated diolefins with weak hydrocarbon acids but obtained very low catalyst efficiencies (about 5 grams/gram catalyst). More recently, the anionic telomerization of butadiene and toluene by sodium on oxide supports (3) and sodium in tetrahydrofuran (4) was studied .also, a potassium amide/lithiated alumina catalyst was used to telomerize butadiene (5). 

DIPROPILENTRIAMINA (Spanish) (56-18-8) see 3,3 -iminodipropylamine. DI-w-PROPYLALUMINUM HYDRIDE (2036-15-9) Extremely flammable liquid. The pure material ignites spontaneously in air. Violent reaction with water. A powerful reducing agent. Violent reaction with oxidizers, alcohols, carbon dioxide, cresols, halogens, halogenated hydrocarbons, methyl ether, nitrogen oxides, phenols, sulfur oxides, tetrahydrofuran and many other materials. Store under inert gas, away from all other materials. Commercial product may be a 15 to 30% solution in hydrocarbons. See also next entry. 

---