The examination of hydrocarbon oils and of saponifiable fats and waxes (Google eBook)

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John Wiley & sons, inc., 1915 - Science - 483 pages
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Page 400 - Now add 50 cc of 50 per cent sulphuric acid (by volume) and immerse the vessel in boiling water for two hours and keep protected from dust and organic vapors, such as alcohol, till the titration is completed. Add from a weighing bottle a slight excess of the ferrous ammonium sulphate (C), making spot tests on a porcelain plate with the potassium ferricyanide (F). Titrate back with the dilute bichromate. From the amount of bichromate reduced calculate the percentage of glycerol.
Page 395 - The dish is placed on a water bath (the top of the 160 oven acts equally well) until most of the water has evaporated. From this point the evaporation is effected in the oven. Satisfactory results are obtained in an oven* measuring 12 inches cube, having an iron plate 0.75 inch thick lying on the bottom to distribute the heat.
Page 398 - NaOH (D) and note carefully the exact amount. Boil gently for 15 minutes, the flask being fitted with a glass tube acting as a partial condenser. Cool as quickly as possible and titrate the excess of NaOH with...
Page 398 - ... colour appears throughout the solution. This neutralisation must be done most carefully. The alkali should be run down the sides of the flask, the contents of which are kept rapidly swirling with occasional agitation or change of motion until the solution is nearly neutralised, as indicated by the slower disappearance of the colour developed locally by the alkali running into the mixture. When this point is reached the sides of the flask are washed down with...
Page 398 - The object of cooling is to avoid any sudden rush of vapors from the flask on adding water and to avoid breaking the flask. Time is saved by adding the water before the contents of the flask solidify, but the contents may be allowed to solidify and the test proceeded with the next day without detriment, bearing in mind that the anhydride in excess is much more effectively hydrolyzed in hot than in cold water.
Page 396 - The dish is allowed to remain in the oven, the temperature of which is carefully maintained at 160 C. for one hour, when it is removed, cooled, the residue treated with water, and the water evaporated as before. The residue is then subjected to a second baking of one hour, after which the dish is allowed to cool in a desiccator over sulphuric acid and weighed. The treatment with water, etc., is repeated until a constant loss of 1 to 1-5 mgrm.
Page 212 - This apparatus consists of a standard needle a inserted in a short brass rod. which is held in an aluminum rod 6 by a binding screw. The aluminum rod is secured in a framework so weighted and balanced that, when it is supported on the point of the needle, the framework and rod will stand in an upright position, allowing the needle to penetrate perpendicularly without the aid of a support. The frame, aluminum rod and needle weigh 100 g with the weight c on the bottom of the frame, while without the...
Page 401 - ... efficient. In using the sampler it is introduced into the drum with the ports closed, and when it has touched the bottom, the ports are opened for a second or two, then closed and withdrawn, and the sample discharged into the receiving vessel by opening the ports. When the drum contains salt which has deposited, the ports must be opened before the sampler is pushed through the salt, thus enabling a portion to be included in the sample. It is, however, almost impossible to obtain a correct proportion...
Page 399 - Add 50 cc of 50 per cent sulphuric acid (by volume), and to the cold undiluted solution add from a weighing bottle a moderate excess of the ferrous ammonium sulphate, and titrate back with the dilute bichromate (B).
Page 211 - The brass collar shall be placed with the smaller end on a brass plate which has been previously amalgamated with mercury by first rubbing it with a dilute solution of mercuric chloride or nitrate, and then with mercury. The sample shall be completely melted at the lowest possible temperature that will bring it to a...

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