Golden Yellow

In a 500 ml. Pyrex round-bottomed flask, provided with a reflux condenser, place a mixture of 40 g. of freshly-distUled phenylhydrazine (Section IV.89) and 14 g. of urea (previously dried for 3 hours at 100°). Immerse the flask in an oil bath at 155°. After about 10 minutes the urea commences to dissolve accompanied by foaming due to evolution of ammonia the gas evolution slackens after about 1 hour. Remove the flask from the oil bath after 135 minutes, allow it to cool for 3 minutes, and then add 250 ml. of rectified spirit to the hot golden-yellow oil some diphenylcarbazide will crystallise out. Heat under reflux for about 15 minutes to dissolve the diphenylcarbazide, filter through a hot water funnel or a pre-heated Buchner fuimel, and cool the alcoholic solution rapidly in a bath of ice and salt. After 30 minutes, filter the white crystals at the pump, drain well, and wash twice with a little ether. Dry upon filter paper in the air. The yield of diphenylcarbazide, m.p. 171 °, is 34 g. A further 7 g. may be obtained by concentrating the filtrate under reduced pressure. The compound may be recrystallised from alcohol or from glacial acetic acid. 

In a plastic container the chemist dissolves her golden yellow freebase oil into some DCM, ether or ethanol. The chemist then starts a steady dripping of the sulfuric acid into the HCl/salt and white, puffy HCI gas will start to exit the glass rod or pipette which is at the end of the hose. That tip is then plunged into the sol-vent/freebase solution to bubble the gas through the solvent. 

Properties. Uranium metal is a dense, bright silvery, ductile, and malleable metal. Uranium is highly electropositive, resembling magnesium, and tarnishes rapidly on exposure to air. Even a poHshed surface becomes coated with a dark-colored oxide layer in a short time upon exposure to air. At elevated temperatures, uranium metal reacts with most common metals and refractories. Finely divided uranium reacts, even at room temperature, with all components of the atmosphere except the noble gases. The silvery luster of freshly cleaned uranium metal is rapidly converted first to a golden yellow, and then to a black oxide—nitride film within three to four days. Powdered uranium is usually pyrophoric, an important safety consideration in the machining of uranium parts. The corrosion characteristics of uranium have been discussed in detail (28). 

Tantalum carbide is produced by carburization of the element or the oxide with carbon, ia a manner similar to the preparation of WC or TiC. Final carburization in a vacuum gives a golden yellow carbide, free of oxygen and nitrogen, that contains 6.1—6.3 wt % C and 0—0.2 wt % graphite. 

Layer-type dezincification is easy to recognize visually. The original component shape and dimensions are usually preserved, but the metal color changes from the golden yellow of zinc brass to the red of ele-... 

Naphthazarin (5,8-dihydroxy-1,4-naphthoquinone) [475-38-7] M 190.2, m 220-230°(dec), m 225-230°, pKEst(i) 9.5, pKEst(2) ll-l Red-brown needles with a green shine from EtOH. Also recrystd from hexane and purified by vacuum sublimation. [Huppert et al. J Phys Chem 89 5811 1985.] It is sparingly soluble in H2O but soluble in alkalis. It sublimes at 2-10mm. The diacetate forms golden yellow prisms from CHCI3, m 192-193° and the 5,8-dimethoxy derivative has m 157° (155°) (from pet ether) [Bruce and Thompson J Chem Soc 1089 7955 IR Schmand and Boldt J Am Chem Soc 97 447 1975 NMR Brockmann and Zeeck Chem Ber 101 4221 1968]. The monothiosemicarbazone has m 168°(dec) from EtOH [Gardner et al. J Am Chem Soc 74 2106 7952]. 

The white solid which collects inside the upper part of the flask is methylsulfur trichloride. This must be washed down with the cold reaction mixture before the flask warms to room temperature. The progress of the chlorination is accompanied by definite color changes. When one-third of the chlorine has been added, the reaction mixture is a deep reddish orange color which gradually fades as more chlorine is added until at the end the color should be a pale golden yellow or light straw color. 

Chelerythrine crystallises from alcohol in colourless, prismatic leaflets, m.p. 207°, containing one molecule of alcohol. The alkaloid absorbs carbon dioxide from the air, becoming yellow. The solutions fluoresce blue when the alkaloid is contaminated with its oxidation product, which is formed by mere exposure of solutions to air. The salts, which are quaternary, are intensely yellow. The hydrochloride, B. HCl. HjO, forms citron-yellow needles, and the sulphate, B. H2SO4.2HjO, golden-yellow needles, sparingly soluble in water the platinichloride, B2. HaPtCl. ... 

Jatrorrhizine (Jateorhizine). (Items 6, 9, 11, 14, 18, 19, 21, 22 list, p. 329.) The iodide, C20H20O4NI. H2O, crystallises in reddish-yellow needles, m.p. 210-2° the chloride C20H20O4NCI. H2O, forms copper-coloured needles, m.p. 206°, and the nitrate golden-yellow needles, m.p. 225° (dec.). On 0-methylation, jatrorrhizine iodide yields palmatine iodide, and on reduction it is converted into dZ-tetrahydrojatrorrhizine, m.p. 217-8°, the d-form of which is corypalmine and which on 0-methylation yields tetrahydropalmatine (p. 292). ... 

Sabadine, CjgHgiOgN, isolated by E. Merck,i crystallises from ether in needles, m.p. 238-240° (dec.). The hydrochloride, B. HCl. 2H2O, has m.p. 282-4° (dec.), the nitrate, B. HNO3, is sparingly soluble in water, and the aurichloride, B. HAUCI4, forms golden-yellow needles. 

Perloline, Cg6H2203N4(0Me)4. HjO, is isolated as the dihydrochloride B. 2HC1.7HjO, which forms golden yellow needles m.p. 220-265 , [a]p =t 0 (H2O). The monohydrated base occurs as pale yellow needles. 

Properties.—Golden yellow plates (from alcohol) m. p. 98 5 insoluble in water it explodes when heated above its nieltinig point. 

The Group 1 elements are soft, low-melting metals which crystallize with bee lattices. All are silvery-white except caesium which is golden yellow "- in fact, caesium is one of only three metallic elements which are intensely coloured, the other two being copper and gold (see also pp. 112, 1177, 1232). Lithium is harder than sodium but softer than lead. Atomic properties are summarized in Table 4.1 and general physical properties are in Table 4.2. Further physical properties of the alkali metals, together with a review of the chemical properties and industrial applications of the metals in the molten state are in ref. 11. 

---