On the Promoter Prevention Fe1-xO from Disproportionation

The invention of Fe_1-xO based catalyst for ammonia synthesis and the discovery of a double peak shape curve between catalytic activity and precursor phase composition (Fe²⁺/Fe³⁺) is a breakthrough in the field of ammonia synthesis.     

Disproportionation of pyrans

Russian Chemical Bulletin -     

Disproportionation of trimethylsilicon 3,5-di-tert-butyl-o-benzosemiquinolate

Conclusions Trimethylsilicon 3,5-di-tert-butyl-o-benzosemiquinolate disproportionates to the quinone and 1,2-bis-(trimethylsiloxy)-3,5-di-tert-butylbenzene.Translated from Izvestiya Akademii NaukSSSR, Seriya Khimicheskaya, No. 7, pp. 1648–1649, July, 1979.     

Disproportionation of unsaturated organosilicon compounds

Russian Chemical Bulletin -     

Cyclic chronocoulemetry: Disproportionation and dimerization reactions coupled to electron transfer

An extension of double-potential-step chronocoulemetry to multiple or cyclic techniques has been developed, and its potential applications in the study of coupled chemical reactions in electrochemistry are discussed. Disproportionation and dimerization mechnisms are considered. Wroking curves have been calculated with the use of the finite difference digital simulation method. It is shown that better resolution for disproportionation and dimerization reactions can be obtained with cyclic chronocoulometry than with double-potential-step chronocoulemetry. The method has been experimentally verified measuring the disproportionation reaction U(V) in 1 mol dm^?3 sodium hydrogen carbonate solutions. A rate coefficient of 15.6 dm³ mol^?1 was calculated for this reaction.     

Thermal Disproportionation of Oxo-Functionalized Graphene

Graphene production by wet chemistry is an ongoing scientific challenge. Controlled oxidation of graphite introduces oxo functional groups; this material can be processed and converted back to graphene by reductive defunctionalization. Although thermal processing yields conductive carbon, a ruptured and undefined carbon lattice is produced as a consequence of CO₂ formation. This thermal process is not understood, but it is believed that graphene is not accessible. Here, we thermally process oxo-functionalized graphene (oxo-G) with a low (4–6 %) and high degree of functionalization (50–60 %) and find on the basis of Raman spectroscopy and transmission electron microscopy performed at atomic resolution (HRTEM) that thermal processing leads predominantly to an intact carbon framework with a density of lattice defects as low as 0.8 %. We attribute this finding to reorganization effects of oxo groups. This finding holds out the prospect of thermal graphene formation from oxo-G derivatives.     

Disproportionation of homoleptic rhodium carbonyls

Both [Rh₄(CO)₁₂] and [Rh₆(CO)₁₆] disproportionate in pyridine to cis-[Rh(CO)₂(py)₂]⁺ and [Rh₅(CO)₁₃(py)₂]⁻. In the same solvent, cis-[Rh(CO)₂(py)₂]⁺ is reduced by CO/H₂O to [(py)₂H][Rh₅(CO)₁₃-(py)₂], which has been structurally characterized.     

Disproportionation rate and products of cyclohexylperoxy radicals

Conclusions The pulse photolysis method was used to measure the rate constant for the disproportionation of cyclohexylperoxy radicals at 12–60°; the practically sole products of this reaction are cyclohexanol and cyclohexanone, which are formed in approximately equal amounts.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 631–634, March, 1979.     

Kinetics of Iodous Acid Disproportionation

The iodous acid disproportionation is autocatalytic, and it is not easy to measure the rate constant of the step 2IO₂H → IO₃^? + IOH + H⁺ separately. Hg(II) was used previously to suppress the autocatalytic pathway, but this method presents difficulties discussed in this work. A more effective method is the use of crotonic acid, an effective IOH scavenger. It suppresses side reactions, and a purely second‐order rate law is obtained. The rate constant decreases from 5 to 0.2 M^?1 s^?1 when the sulfuric acid concentration increases from 0.08 to 0.60 M. The observed decrease could be explained if IO₂^? reacts faster than IO₂H. This may have consequences for the mechanism of the oscillating Bray–Liebhafsky reaction.     

Thermal Disproportionation of Hypophosphorous Acid

Thermal disproportionation of hypophosphorous acid was studied to find the reaction order, the rate constant and activation energy of the process, and also the temperature ranges in which the reaction rate is the highest.     

Disproportionation of ethylbenzene over SAPO-40

SAPO-40 exhibits strong acid sites which catalyze the disproportionation of ethylbenzene. The distribution of diethylbenzene isomers suggests a high void volume in the structure of this molecular sieve.