oxidation of n -alkanes.
Generally, selective oxidation of alkanes with O 2 has faced two major problems: chemoselectivity and regioselectivity [ 13 , 14 ]. Moreover, alkanes do not possess neither orbitals of sufficiently high ionization energy
A series of Ag–Pd/C catalysts with different Ag/Pd molar ratios were prepared by impregnation and characterized by N2 adsorption and XPS. The catalytic performance was investigated in the hydrodechlorination of carbon tetrachloride into chloroform.
High selectivity toward chloroform, near 100%, was obtained over Ag–Pd/C bi-metal catalysts. A very pronounced surface enrichment
with Ag in Ag–Pd/C catalysts determined by XPS may be responsible for the high selectivity of chloroform. It is suggested
that hydrodechlorination of carbon tetrachloride into chloroform occurs on the surface of Ag in the Ag–Pd alloy and the role
of Pd is to supply H atoms necessary.
Authors:Frederico A. D. Araújo, Sonia V. Pereira, Deivson C. S. Sales, A. R. Schuler, and Cesar A. M. Abreu
presence of diluted sulfuric acid. A model representing the evolutions of the fatty ester concentrations was fitted to the experimental results of the batch esterifications, and the kinetic parameters were quantified. The selectivities of the methyl and
The principles of selective separations by recrystallization are explained and formulae for the calculation of decontamination
factors are presented. Experiments with strontium sulfate and radioactive strontium ions demonstrate the validity of the theoretical
considerations. Similar or higher decontamination factors are found than those calculated for a uniform distribution of the
radioactive strontium ions between crystals and solution. The high values are explained by assuming a recrystallization mechanism
which consists of dissolution and redeposition of crystal layers. The half-times of recrystallization increase sharply with
Sr2+ or SO
concentration in the solution. In nitric acid solutions as well as in mixtures containing nitrates and nitric acid the solubility
of strontium sulfate is rather high, accordingly the decontamination factors are low under these conditions and furthermore
the recrystallization half-times are long.
number of highly cited clinical articles correlated with drug research success (assessed by expert judgment) even better than the number of all clinical articles.
We have previously proposed a bibliometric indicator, the Top Journal Selectivity