Introduction to the study of organic chemistry : a text-book for students in the universitites and technical schools / by John Wade.

  • Wade, John.
Date:
1898
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Licence: Public Domain Mark

Credit: Introduction to the study of organic chemistry : a text-book for students in the universitites and technical schools / by John Wade. Source: Wellcome Collection.

    445/490 (page 423)
    intimately with ^ gram of zinc dust. Heat in test tube, but first expel air by dry carbon dioxide. Collect gas and note odour, smoky flame; apply metallic tests. [Trichloracetic Acid.—10 grams chloral hydrate, 8 c.c. red nitric acid, sp.-gr. = 1-6. Note yield (50 %). Prove hydrolysis to chloroform and car- bonate on 1 gram.] [Cliloracetic Acid. —100 c.c. glacial acid; 10 grams flowers of sulphur. Note m.-pt.] [Chloral.—100 c.c. rectified spirit. Note b.-pt. and convert into hydrate.] Chloral Hydrate.—Hydrolyse 1 gram with cold soda. Filter from chloro- form (which prove) and test for formate. Reduces ammoniacal silver f quickly, and alkaline copper tartrate (p. 426). Gives rosaniline aldeuyde reaction. Reduce igram in water with sodium amalgam in same way as aldehyde. After two or three days, pour off-and distil and test alcohol. Qualitative Tests for Chloral (p. 118).—Volatile with steam. Odour. Hydrolysis. Rosaniline. Reduces ammoniacal silver and alkaline copper tartrate. Phenyl isocyauide as with chloroform. Gives reddish-brown ppt. with ammonium sulphide, especially on warming. CHAPTER XXI [Gly collie Acid.—A fair yield by boiling potassium chloracetate solution (acid exactly neutralised) in reflux apparatus for several hours. Potassium chloride separates first on concentration. Evaporate remaining soln. to dry- ness and extract acid with hot abs. alcohol. Note acid reaction of solu- tion. Distil some crystals with cone, sulphuric acid. Note carbon monoxide and crystals of paraformaldehyde. Oxidise some with cone, nitric acid. Evap. to dryness and test for oxalic acid.] \Glycol.—10 c.c. ethylene dibromide, 16 grams dry potassium carbonate, 150 c.c. water. Note sweet taste, b.-pt., and oxidation to oxalic acid.] Oxalic Acid from Su gar.— 20 grams cane sugar, 50 c.c. cone, nitric acid. Warm (very heavy fumes). Try two or three times if necessary. Recrystal- lise from small qts. of water until free from nitric acid. Note acid reaction, aud loss of water at 100°. Test tube in beaker of boiling w'ater, with dry air (calcium chloride tube) sucked through. Note sublimed crystals. Qualitative Tests for Oxalates (p. 126).—Calcium salt (calcium chloride to neutral oxalate) insol. in water and boiling acetic acid. Heated gently on - platinum foil leaves a residue of calcium carbonate, which effervesces with acids. With cone, sulphuric acid, carbon monoxide and dioxide. With warm acid permanganate, carbon dioxide evolved and permanganate decolourised. Ammonium Oxalates.— Solution of 20 grams acid into two equal parts. First exactly neutralised with ammonia and evaporated to crystallisation—■ normal oxalate. Second again divided ; first half neutralised and mixed with second half, and evaporated as before—acid oxalate. Note different shape of crystals and acidity to litmus. Ethyl Oxalate.—40 grams cryst. oxalic acid dehydrated in a flask as above until no further loss of weight (11| grams). Heat with 25 c.c. abs. alcohol as directed (thermometer in liquid) passing in vapour of 33 c.c. more as in steam distillation. Fractionate. Note b.-pt. and sp.-gr. Gse the distilled alcohol for oxamide (below). Hydrolysis of Ethyl Oxalate.—As usual. 33 c.c. Prove alcohol and sodium oxalate. Oxamide.—Ammonia to distilled alcohol from ethyl oxalate preparation. Also to 1 c.c. of pure ethyl oxalate. Wash ppt. and dry and filter. Hydrolysis of Ethyl Oxalate.—In test tube. Prove ammonia aud oxalate. Nitrous acid, as acetamide. Oxalonitrile.—Heat i gram of oxamide with little phosphorus pentoxide in small bulb tube, and note pink flame of evolved gas.