A-Benzoin oximes

Benzoic acid, 706,711, 752,755,756 Benzoic anhydride, 794 Benzoin, 708,714 Benzoin condensation, 708, 714 a-Benzoin oxime, 958 Benzonitrile, 609, 803 hydrolysis of, 609 ... 

Green precipitate of the a-benzoin oxime salt derivative... 

Black. Te present. Boil with HC1 to remove dissolved S02 and treat successively with 10 per cent KSCN solution and a little SnCl2 solution. Red colouration, soluble in ether. Mo present. Confirm by potassium xanthate test or by the a-benzoin oxime test. (Section vn.6)... 

If the alternative potassium hydroxide method is employed for the separation of Groups IIA and IIB, the KOH extract may contain As, Sb, Sn, Se, Te, and part of the Mo the residue may contain, in addition to HgS, PbS, Bi2S3, CuS, CdS, and PdS, the gold and platinum partly as sulphides and possibly partly in the form of the free metals. Mo is readily identified by the potassium xanthate or a-benzoin oxime test. The Au and Pt will accompany HgS after extraction with dilute nitric acid upon dissolution in aqua regia, Pt may be identified as the dimethylglyoxime complex in the presence of m hydrochloric acid after the Pb, Bi, Cu, and Cd have been removed. 

Figure 1 Selection of typical organic precipitating agents (commonly precipitated transition metal ions given in parentheses) (a) dimethylglyoxime (Ni +, Pd ), (b) 1-nitroso-2-naphthol (Fe +, Co +, Zr +, Pd +), (c) a-benzoin oxime ( cupron ) (Cu, Mo02, W02 ), (d) ammonium V-nitroso-V-phenyUiydroxylamine ( cup-ferron ) (Ti +, V02", Fe +, Zr +, 06 +, U +), (e) 8-hydroxyquino-line ( oxine ) (TiO"+, Fe +, 01 +, Zr +, Mo02 +, W02 +, Th +, U02 ), (f) 4-hydroxyphenylarsonic acid (Ti +, Zidfi...

Figure 6.1S. Amperotnetric titration curves, (a) Only substance titrated is reducible, c.g. Pb2 against SOJ", Ag against halide, (b) Only titrant is reducible, c.g. SO " against Pb, Na2S20] against I2. (c) Both reducible, c.g. Pb against CrOJ", Cu against a-benzoin oxime...

Benzene-4-sulfonic acid, l-hydroxy-2-(2-hydroxy-6-suIfo-l-naphthylazo)-6-(2-hydroxy-l-naphthylazo)-metallochromic indicator, 556 Benzimidazole, 2-(o-hydroxyphenyl)-raercury determination, 532 Betrzoic acid complexes linkage isomers, 186 a-Benzoin oxime in gravimetry, 530 Benzothiazole, hydroxy-in gravimetry, 531 Benzothiazole, mercapto-in gravimetry, 534 Benzothiazole, 2-mercapto-cadmium complexes liquid-liquid extraction, 547 Benzoxazole, 2-(o-hydroxyphenyl)-cadmium determination, 531 Benzylamine, a-methyl-Al,7V-dimethyl-complexes chirality, 199 Berry pseudorotation, 39 Beryllium analysis, 523... 

Precipitate, the molybdenum by the addition of 0. 25 ml of 1% alcoholic a-benzoin oxime and allow to stand for 5 minutes. Centrifuge and, if required, reserve precipitate for molybdenum purification. 

Although normally applied in trace analysis, a substoicheiometric isotope dilution method has been reported by McClendon and DeVoe for the determination of W at high concentration using toluene-3,4-dithiol. More recent work has applied this reagent to the measurement of tracer levels of W in steel, meteorites, and kale by an n.a.a. method. Baishya and Heslop have endorsed the use of toluene-3,4-dithiol for both isotope dilution and activation methods for the determination of W, but reject 8-hydroxyquinoline, a-benzoin oxime, and cupferron. ... 

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