Colourants amorphous

Poly (acetylenes) [16], There are several catalysts available for polymerization of substituted acetylenes. Whereas Ziegler-Natta catalysts are quite effective for polymerization of acetylene itself and simple alkylacetylenes, they are not active towards other substituted acetylenes, e.g. phenylacetylenes. Olefin-metathesis catalysts (Masuda, 1985 Masuda and Higashimura, 1984, 1986) and Rh(i) catalysts (Furlani et al., 1986 Tabata, 1987) are often employed. In our experience, however, many persistent radicals and typical nitrogen-containing functional groups serve as good poisons for these catalysts. Therefore, radical centres have to be introduced after construction of the polymer skeletons. Fortunately, the polymers obtained with these catalysts are often soluble in one or other organic solvent. For example, methyl p-ethynylbenzoate can be polymerized to a brick-coloured amorph- See the Appendix on p. 245 of suffixes to structural formula numbers. 

Tellurium Nitride.—The formation of this compound has already been mentioned (see p. 375). It is obtained when anhydrous liquid ammonia reacts in the cold with a tetrahalide of tellurium. It is deep yellow in colour, amorphous, and when dry extremely explosive. Its composition has not been determined with certainty, but its empirical formula is probably TeN or Te3N4. 

The chocolate-coloured amorphous powder which was made by B. Courtois,4 about 1813, by the action of an aq. soln. of ammonia on solid iodine, was thought by J. L. Gay Lussac, J. J. Colin, J. W. Mallet, and C. Stahlschmidt to be nitrogen... 

Nickel Thiocyanate, Ni(CNS)2, has been obtained in the anhydrous condition as a chocolate-coloured amorphous powder. The hydrated salt, 2Ni(SCN)a.3HaO, obtained by dissolving nickel carbonate in thio-cyanic acid is a yellowish brown crystalline powder.10 Double salts... 

A white to light tan-coloured, amorphous or microcrystalline powder, which gradually darkens on exposure to light. M.p. 144° to 148°. 

Physical form Yellow coloured, amorphous with typical smell. Solubility ... 

As a by-product, the weathering processes occurring in the rhizosphere have produced yellowish-coloured amorphous Ee-oxyhydroxides that revealed the thickness of the soil affected by root activity, where chemical, mineralogical and biological properties were changed with respect to the bulk. 

Now take another batch of sulphur flowers, but this time heat it well past its melting point. The liquid sulphur gets darker in colour and becomes more and more viscous. Just before the liquid becomes completely unpourable it is decanted into a dish of cold water, quenching it. When we test the properties of this quenched sulphur we find that we have produced a tough and rubbery substance. We have, in fact, produced an amorphous form of sulphur with radically altered properties. 

Although the polymer has a regular structure, it is amorphous, the natural polymer being transparent and oreuige in colour. 

X-ray evidence shows the material to be completely amorphous as might be expected from such a complex mixture. The specific gravity ranges from 1.05 to 1.10. It is slightly harder than gypsum and therefore just not possible to scratch with a fingernail. Yellow in colour, it is less brittle than other hard natural resins and may therefore be carved or machined with little difficulty. The refractive index is 1.54. 

EtOH). No methoxyl is present. It forms a series of crystalline double chlorides with cadmium, zinc or copper, does not give the thalleioquin reaction, and solutions of its sulphate are not fluorescent. It is diacidie and forms two series of salts of which the nitrate, B. HNOj, crystallises in minute prisms, m.p. 196°, insoluble in water. Cinchonamine hydrochloride, B. HCl, laminae or B. HCl. HjO, cubical crystals, has been suggested for use in the estimation of nitrates. When warmed with strong nitric acid the alkaloid furnishes dinitrocinchonamine. It gives an amorphous, monoacetyl derivative, and forms a methiodide, m.p. 208 , which with silver oxide yields an amorphous methylcinchonamine. Raymond-Hamet found that cinchonamine ves typical indole colour reactions and is probably an indole alkaloid. This seems to have been... 

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