Significance: A simple and efficient method for the preparation of a new polystyrene-supported TEMPO by using click chemistry was described. Propargylation of commercially available 4-hydroxy-TEMPO 1 led to propargyl ether TEMPO 2. TEMPO 2 was readily grafted by the copper(I)-catalyzed azide-alkyne cycloaddition onto polystyrene resin to give PS-CLICK-TEMPO 3. The new heterogeneous PS-CLICK-TEMPO 3 promoted the selective oxidation of aliphatic and benzylic alcohols with sodium hypochloride as terminal oxidant and KBr as co-catalyst (92-99% yield). Catalyst 3 was readily recovered by filtration and reused for the next cycle without further activation in five subsequent runs employing 4-methylbenzyl alcohol as substrate (92-95% yield).Comment: The authors have developed a simple and practical protocol for grafting TEMPO onto polystyrene resin. PS-CLICK-TEMPO 3 (5 mol% of catalyst loading) also showed outstanding activity for the aerobic oxidation of alcohol using Mn(II)-Co(II) nitrate in acetic acid under ambient pressure and temperature (95-98% yield). Under these conditions PS-CLICK-TEMPO 3 was recovered by simple filtration and reused five times for aerobic oxidation (4-bromobenzyl alcohol as the substrate, 91-95% yield).
The paper addresses mainly an advanced way of statistical data processing applied to a Round Robin spectrochemical laboratory scheme. This may be applied with adequate modification to the proficiency testing scheme or to other interlaboratories comparisons. BIOMAT and ICEM organized a six laboratories Round Robin scheme designed to demonstrate the competence of the three laboratories that candidate to RENAR accreditation to perform OES-SDAR analysis. The other accredited ones are interested in this scheme to demonstrate that their spectrochemical analysis proficiency is improved or are at the level they were accredited. There were analyzed two MRCs (medium alloyed steel and Al-Cu-Zn alloy) and were dozed simultaneously 10 and 8 elements, respectively. Because of the different Z scores obtained by the laboratories for the same sample it is quite impossible to classify the laboratories competence. In this regard, the authors introduced a new way of classification of the laboratory's analytical competence based on the mean Z score and its associated dispersion.
"During the standard pumping of an oil well, the sucker rods are subjective to alternative stress (tensile and compression). Certain steel grades have different behavior, taking into consideration their mechanical properties, like tensile strength. While most operators consider that, the higher the ultimate tensile strength (UTS) of a material is, it will behave better when subjected to loads. This paperwork shows that, comparing three different steel grades, they may have different results on the Goodman diagram, than expected. We are going to show that, even the steel grades have the same tensile strength (115 ksi), when calculating the %Goodman, the steel have different behavior, and this results from the manipulation of coefficients “A” and “b” involved in the formula, that each sucker rods manufacturer validates. "
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