Platinum-Cobalt

Platinum-cobalt alloys have magnetic properties. One such alloy made of 76.7% Pt and 23.3%... 

Platinum catalysts Platinum-cobalt alloys Platinumcompounds... 

Procedures for determining the quaUty of formaldehyde solutions ate outlined by ASTM (120). Analytical methods relevant to Table 5 foUow formaldehyde by the sodium sulfite method (D2194) methanol by specific gravity (D2380) acidity as formic acid by titration with sodium hydroxide (D2379) iron by colorimetry (D2087) and color (APHA) by comparison to platinum—cobalt color standards (D1209). 

Apparent equivalent weight deterrnined by titration with hydrochloric acid. APHA color determined by ASTM D1209, platinum—cobalt method. 

Color. Many water samples have a yellow to brownish-yeUow color which is caused by natural substances, eg, leaves, bark, humus, and peat material. Turbidity in a sample can make the measurement of color uncertain and is usually removed by centrifiigation prior to analysis. The color is usually measured by comparison of the sample with known concentrations of colored solutions. A platinum—cobalt solution is used as the standard, and the unit of color is that produced by 1 mg/L platinum as chloroplatinate ion. The standard is prepared from potassium chloroplatinate (K PtCl ) and cobalt chloride (C0CI26H2O). The sample may also be compared to suitably caUbrated special glass color disks. 

Thermal Properties. The thermal stabiUty of cellulose esters is deterrnined by heating a known amount of ester in a test tube at a specific temperature a specified length of time, after which the sample is dissolved in a given amount of solvent and its intrinsic viscosity and solution color are deterrnined. Solution color is deterrnined spectroscopically and is compared to platinum—cobalt standards. Differential thermal analysis (dta) has also been reported as a method for determining the relative heat stabiUty of cellulose esters (127). 

Reduction of unsaturated aldehydes seems more influenced by the catalyst than is that of unsaturated ketones, probably because of the less hindered nature of the aldehydic function. A variety of special catalysts, such as unsupported (96), or supported (SJ) platinum-iron-zinc, plalinum-nickel-iron (47), platinum-cobalt (90), nickel-cobalt-iron (42-44), osmium (<55), rhenium heptoxide (74), or iridium-on-carbon (49), have been developed for selective hydrogenation of the carbonyl group in unsaturated aldehydes. None of these catalysts appears to reduce an a,/3-unsaturated ketonic carbonyl selectively. 

Platinum-cobalt alloy, enthalpy of formation, 144 Polarizability, of carbon, 75 of hydrogen molecule, 65, 75 and ionization potential data, 70 Polyamide, 181 Poly butadiene, 170, 181 Polydispersed systems, 183 Polyfunctional polymer, 178 Polymerization, of butadiene, 163 of solid acetaldehyde, 163 of vinyl monomers, 154 Polymers, star-shaped, 183 Polymethyl methacrylate, 180 Polystyrene, 172 Polystyril carbanions, 154 Potential barriers of internal rotation, 368, 374... 

Not darker than color standard No 5 of ASTM platinum-cobalt scale Not more than 1° and shall... 

Color. Det color in accordance with ASTM D1209. The sample is comparedspectro-photometrically against platinum-cobalt standard solns... 

Palladium electrocatalysts, 183 Palladium-alloy electrocatalysts, 298-300 Pareto-optimal plot, 85 Platinum-alloy electrocatalysts, 6, 70-71, 284-288, 317-337 Platinum-bismuth, 86-87, 224 Platinum chromium, 361 362 Platinum-cobalt, 71, 257-260, 319, 321-330, 334-335 Platinum-iron, 319, 321, 334-335 Platinum-molybdenum, 253, 319-320... 

Koyuncu et al. [56] presented pilot-scale studies on the treatment of pulp and paper mill effluents using two-stage membrane filtrations, ultrafiltration and reverse osmosis [56]. The combination of UF and RO resulted in very high removals of COD, color, and conductivity from the effluents. At the end of a single pass with seawater membrane, the initial COD, color and conductivity values were reduced to 10-20 mg/L, 0-100 PCCU (platinum cobalt color units) and 200-300 ps/cm, respectively. Nearly complete color removals were achieved in the RO experiments with seawater membranes. 

In the early 1970 s when samarium-cobalt magnets were first being proposed as a replacement for platinum-cobalt in microwave tubes, few could have anticipated the success that was to follow. Notwithstanding the traumas brought about by a quadrupling of cobalt prices, their use has grown steadily to the point where they now command a vitally important position in the permanent magnet market. 

Other publications, which include "Interstate Commerce Commission Rules and Regulations for the Transportation of Explosives and Other Dangerous Articles , and ASTM (American Society for Testing and Materials) Dl209-69 publication, entitled "Standard Method of Test for Color of Clear Liquids (Platinum-Cobalt Scale) are listed in the same Spec... 

Appearance. Ether shall be no darker than the 20 Platinum-Cobalt Standard when tested as specified in paragraph 4.3-1... 

Color — not darker than No 10 on the platinum-cobalt scale as prescribed by ASTM Method D1209. This method is described in this Vol, under "Ether, Diethyl US Armed Forces Specification Requirements and Tests pp E186 to E188... 

Color. Standards Stock standard. Dissolve 1.245g of potassium chloroplatinate (K2PtCl6) and l.OOOg of cobaltous chloride (C0CI26H2O) in water. Add 100ml of coned HQ, and dilute the soln to 1000.0ml with water. (This soln has a color of 500 on the APHA and ASTM platinum-cobalt scales)... 

Heat Test Color shall not be darker than that of the 75-ppm platinum cobalt standard when detd as descrihed below ... 

Table III gives a survey of the essential characteristics of the alcohols. It is remarkable that, despite the poor color value of the sulfuric acid test, esters can be obtained from the two hexanols with color values falling within the range of the platinum cobalt scale from 35 to 50.

The freezing point measurement, standard method for the detennination of styrene assay until the 1970s, has been largely replaced by gas chromatography. Color is measured spectrophotometrically and registered on the APILA or the platinum-cobalt scale. 

A wide variety of metals are active hydrogenation catalysts those of most interest are nickel, palladium, platinum, cobalt, iron, nickel-promoted copper, and copper chromite. Special preparations of the first three are active at room temperature and atmospheric pressure. The metallic catalysts are easily poisoned... 

The passage of acetylene alone, over the nietals nickel, platinum, cobalt and iron gives the following results. 

The formation of complexes of l,2,3,4-thiatriazole-5-thiol has been well described in CHEC-II(1996) 1,2,3,4-thiatriazole-5-thiol can form complexes with various metals such as palladium, nickel, platinum, cobalt, zinc, etc. <1996CHEC-II(4)691>. These complexes can be prepared either by cycloaddition reactions of carbon disulfide with metal complexes of azide anion (Equation 20) or directly from the sodium salt of l,2,3,4-thiatriazole-5-thiol with metal salts. For instance, the palladium-thiatriazole complex 179 can be obtained as shown in Equation (20) or it may be formed from palladium(ll) nitrate, triphenylphosphine, and sodium thiatriazolate-5-thiolate. It should be noted that complexes of azide ion react with carbon disulfide much faster than sodium azide itself. 

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