Flame-treated platinum

Figure 13.4.4 First cyclic voltammograms of flame treated platinum of different orientations in O.5MH2SO4 at 50mV/s. Positive potentials are plotted to the right, and anodic currents up. Compare these to the voltammogram of a polycrystalline electrode. Figure...

On the other hand, for a given electrolyte, the distribution of the adsorption states up to 0.8 V vs. RHE depends on the degree of the surface order of the platinum single crystal. Adsorption states at higher potentials are related to the presence of wide two-dimensional ordered (100) domains [11,62]. The maximum development of these states was obtained after cooling a flame-treated sample in an oxygen-free atmosphere [3,11,62,63]. 

Thermal treatment—Processes in which vapor-phase contaminants are destroyed via high-temperature oxidation the primary categories of thermal treatment used to treat MTBE and other oxygenates include thermal oxidation, which employs a flame to generate the high temperatures needed to oxidize contaminants, and catalytic oxidation, which employs lower temperatures in the presence of a catalyst (typically platinum, palladium, or other metal oxides) to destroy contaminants. 

Forchhammer evaporated six pounds of sea water from the Sound near Copenhagen and heated the residue to white heat in a perfectly clean platinum crucible. After further purification of the remaining hemi-prismatic crystals, he treated them with alcohol and detected boron by the green color it imparted to the alcohol flame and the brown color it gave to curcuma paper. In 1877 L. Dieulafait found boric acid to be a normal constituent of sea water (124). Its presence in many mineral waters has also been demonstrated. 

C) lf the sample is a propellant, treat 1-2 g in a tared crucible (porcelain or platinum) with a few drops of coned nitric acid and heat on a steam bath, under the hood, until the evolution of nitrogen oxides subsides. Continue heating until the liquid fraction evaporates, thus leaving a gummy mass. Transfer the crucible to a triangle, and using a low flame heat carefully until most of the carbonaceous matter has been burned off. Finish the combustion at ca 600° for ca 1 hr, cool in a desiccator and weigh (Refs 1 2)... 

A hydrocarbon, compound A (CgHio), burned with a yellow, almost nonsmoky flame. On catalytic hydrogenation over platinum catalyst it absorbed 1 mol of hydrogen to form compound B. It also decolorized a Br2- H2Cl2 solution to yield a dibromo derivative, compound C. Ozonolysis of the hydrocarbon gave only one compoimd, D. Compoimd D gave a positive iodoform test when treated with iodine-sodium hydroxide solution. On treatment of compoimd D with an alcoholic solution of silver ammonium hydroxide, a silver mirror was formed within a few minutes. 

To test for positive ions, add 300 milligrams of the sample to be tested to water and mix. Filter the slurry and divide the filtered solution into two parts. To one part of the solution add a drop of a saturated sodium sulfate solution. Barium or strontium will come out of the solution as a white precipitate. A flame test on a platinum wire, using the part of the solution that was not treated with sodium sulfate, identifies barium or strontium. A green flame is produced by barium salts and a red flame is produced by strontium salts. To find the quantities of barium and strontium, add sodium sulfate until no more precipitation is formed. Filter and weigh the precipitate. The untreated aqueous solution may be flame tested for sodium and potassium. A yellow and violet flame is produced respectively, although the potassium test is diffcult. NH4 can be detected by an ammonia smell after the solution has been made basic with sodium hydroxide. 

---