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.

    447/490 (page 425)
    together and evaporate on sand bath until viscid. Absol. alcohol 1 c.c. for every gram of powdered solid. Hydrogen chloride as with ethyl chloride. Heat on w.-b. 21 hours and saturate again. Note b.-pt. and yield (45 % theor.) Convert 5 c.c. into malonic acid. Note m.-pt. and decomposition into acetic acid, which identify.] [Malonic Acid Synthesis of Butyric Acid.—On 10 c.c. of ethyl malonate. Calculated quants. Note b.-pt. and m.-pt. of ethyl derivatives, and identify butyric acid (yield 80%).] CHAPTER XXYI f Succinic Acid Synthesis.—10 c.c. ethylene bromide, 17 grams pure crys- tallised cyanide, 100 c.c. abs. alcohol. After filtering potassium bromide from cold product, 10 grams caustic soda (jield 50%).] Qualitative Tests for Succinic Acid (p. 157).—Calcium salt soluble, except in presence of alcohol and ammonia. Ferric salt red and gelatinous; no crystals with hydrochloric acid (see Beizzore acid). Acid melts on platinum foil, gives off suffocating fumes, and burns with clear flame. CHAPTER XXVII Tartaric Acid.—Prepare from 30 grams argol. Note m.-pt. [.Racemic Acid.—Heat 10 grams tartaric acid with 1 c.c. water in sealed tube. Recrystallise until m.-p. const.] Qualitative Tests for Tartaric Acid (p. 165).—Chars on heating. Burnt sugar odour. Calcium salt (calcium chloride and neutral tartrate) appears in cold, but sol. in acetic acid and caustic soda. Reappears on boiling latter solution. Tartrate to copper sulphate prevents pptn. of oxide by caustic soda, simply dark blue solution. Tartrates reduce ammoniacal silver nitrate. (Distinction from citrate). Potassium hydrogen tartrate (potassium chloride and acetic acid) sparingly soluble, and appears on rubbing sides of tube. Solid Formulas of Tartaric Acids.—Fasten pairs of tetrahedra together with paper fasteners before sealing up, Ten tetrahedra wanted for complete set. Qualitative Tests for Citric Acid (p. 169).—Calcium salt appears only on boiling. Citrates do not reduce silver. Potassium hydrogen citrate soluble. [Conversion of Citric Acid into Acetone.—20 grams in cone, sulphuric acid (start with 20 c.c.) as indicated. Distil acetone-carboxylic acid, and prove carbon dioxide and acetone. Latter by b.-pt., bisulphite, and oxn. to carbon dioxide and acetic acid.] CHAPTER XXVIII Qualitative Tests for Cane Sugar (p. 173).—Non-volatile. Syrup or cry- stals on evapu. on w.-b. Chars with heat or cone, sulphuric acid; burnt sugar odour. Pale yellow with boiling caustic soda. No reduction of al- kaline copper tartrate, unless soln. previously boiled with hydrochloric acid and neutralised. No osazone. [Estimation of Cane Sugar.—Invert 100 c.c. soln., which should contain about aijth of its weight of sugar, by heating it at 100° for 15 minutes with 5 c.c. cone, hydrochloric acid. Neutralise with sodium carbonate, make up to 500 c.c., and then as with glucose; 10 c.c. Fehling’s soln.=0'0475 gram cane sugar.] Hydrolysis of Cane Sugar.—Half-gram sugar in 50 c.c. water and few drops of dil. hydrochloric acid. Heat on w.-b. for 15 minutes. Neutralise with sodium carbonate, and test with alkaline copper tartrate, as with glucose. Test original sugar soln. also. [Qlucose.—100 c.c. meth. spirit and 4 c.c. cone, hydrochloric acid at 45°. 35 grams powdered cane sugar. Yield 50%.] Qualitative Tests for Glucose (p. 174).—Non-volatile. Sweet syrup on evapn. on w.-b. Not blackened by cone, sulphuric acid if pure. Dark