Liquid colours

C-jHg. A slightly coloured liquid, b.p. 90 C, obtained by a Diels-Alder reaction between cyclopcntadiene and ethyne at approximately 150°C. At temperatures in excess of 450°C it rearranges to cycloheptatriene (tropilidene). 

Appearance amber liquid light yellow liquid light yellow liquid straw coloured liquid... 

Strychnicine. This alkaloid, isolated from nux-vomica leaves grown in. lava, forms needles, m.p. 240° dec.), and is characterised by the following colour reaction. When sodium hydroxide solution is added drop by drop to a solution of a salt of the alkaloid in water, the precipitate formed dissolves on addition of more alkali, forming an orange-coloured liquid which develops a violet colour on addition of hydrochloric acid. Strychnicine is scarcely poisonous, but is said to produce tetanus in frogs. 

Jasmone, CjjHjgO, is a ketone found in essential oil of jasmin, and also in neroli oil. It is a dark-coloured liquid with a powerful jasmin odour, and having the following characters —... 

In recent studies, a new line of PGM collectors had been developed [13] known as the PM series. These collectors are an ester-modified mixture of xanthate + mercaptan. The reaction product forms an oily greenish-coloured liquid. The results obtained using the PM series of collectors are shown in Table 18.5. High PGM recovery was obtained using a combination of sodium amyl xanthate plus collector PM301. 

Description Light-coloured liquid with a slight odour (Agency for Toxic Substances and Disease Registry, 1993 Verschueren, 1996)... 

Cobaltous bromide and cobaltous iodide in the solid state absorb ammonia with formation of hexammino-cobaltous bromide, [Co(NH3)6]Br2, and hexammino - cobaltous iodide, [Co(NH3)6]I2, respectively. The compounds are unstable, and rapidly lose ammonia on heating and decompose on solution in water. Tetrammino-cobaltous iodide, [Co(NH3)4]I2, is also known. It may be prepared by treating a concentrated solution of cobaltous iodide with ammonia a pale red precipitate is formed, which gradually dissolves on warming, giving a violet-coloured liquid from which small rose-red crystals of the tetram-mine separate. It also is unstable, and decomposes on heating or on standing in air with loss of ammonia and formation of cobalt oxide. In aqueous solution it turns brown, ammonia is evolved, and a precipitate of cobaltous oxyiodide separates. 

Clear, coloured liquids having a fresh mint taste. 

Chromyl Chloride (Cr02Cl2).—A mixture of 4 parts sodium chloride, 5 parts potassium dichromate and 9 parts fuming sulphuric acid is placed in a retort and distilled until coloured liquid no longer passes over. The chromyl chloride is then redistilled (B.P. 116°). 

Fig. 2.12. Sudden switch from clear to coloured liquid in laminar flow in a pipe...

Alkalinity and Lime.—These are determined as in defecated juice, but for the alkalinity only 20-25 c.c. of juice are taken, and this is then diluted sufficiently to give a slightly coloured liquid. If the juice is so highly coloured that the change of colour with phenolphthalein cannot be detected with certainty, sensitive litmus paper is used and a drop of the liquid removed and tested from time to time during the titration. 

H stretching vibration of the alcohol, has completely disappeared (about 15 minutes). Discard the dark lower aqueous acid layer and dry the pale brown organic layer over anhydrous potassium carbonate for about 2 hours a fresh portion of anhydrous potassium carbonate should be added after 30 minutes. Remove the drying agent by filtration. The yield of deep straw-coloured liquid, which consists of 3-chloro-3-methylpent-l-yne (c. 73%) and... 

Petroleum or crude oil is a thick, dark coloured liquid. It is a mixture of various hydrocarbons. Crude oil or petroleum cannot be used as it is. The various hydrocarbons have to be separated. 

The liquid product obtained from acetylene and hydrogen at temperatures not above 200° is fluorescent, not attacked appreciably by a mixture of sulphuric and nitric acids, and presents the characteristics of American petroleum, Acetylene alone, yields a green-coloured liquid which resembles Russian petroleum. 

As each particle can be detected as spot of light, therefore, slit ultramicroscope helps to determine the number of particles in a definite volume. The great value of the slit consists in the ability by its use to suction off a portion of the fluid which is being examined. Zsigmondy (1912) devised an immersion ultramicroscope, which was used with strongly coloured liquids. In it, illumination objective and microscope objective are brought as close as possible, and the liquid to be investigated can be used as a drop between the two lenses. 

Steam distillation of the crushed seeds of large cardamom yielded 2.5% dark brown-coloured liquid with the following physical constants specific gravity (29°C), 0.9142 refractive index (29°C), 1.460 optical rotation in chloroform, 18°C. 

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