The newer glasses, on the other hand, contain a much wider variety of chemical constituents, the most important being the oxides of barium, magnesium, aluminium and zinc, used either with or without the addition of the bases already named in reference to the older glasses, and - among acid bodies - boric anhydride (B20 3) which replaces the silica of the older glasses to a varying extent.
Kulisch, Monats., 1894, 15, p. 276); by the action of phosphorus pentachloride on hydrocarbostyril (the inner anhydride of ortho-aminohydrocinnamic acid), the chlorinated compound first formed being then reduced by hydriodic acid (A.
It is also formed by heating benzoic anhydride with glycocoll (Th.
Bamberger (Ber., 18 94, 27, p. 9 1 4) obtained the diazoic acids, R NH NO 2, substances which he had previously prepared by similarly oxidizing the diazonium salts, by dehydrating the nitrates of primary amines with acetic anhydride, and by the action of nitric anhydride on the primary amines.
The trans-acid is a racemic compound, which on heating with acetyl chloride gives the anhydride of the cis-acid.
It may be obtained in small quantity by passing ethylene or acetylene into boiling sulphur; by passing ethyl sulphide through a red-hot tube; by heating crotonic acid, butyric acid or erythrite with phosphorus pentasulphide; by heating succinic anhydride with phosphorus pentasulphide or sodium succinate with phosphorus trisulphide (J.
It forms an anhydride when heated.
Glucoseoxime on warming with acetic anhydride is simultaneously acetylated and dehydrated, yielding an acetylated gluconitrile, which when warmed with ammoniacal silver nitrate loses hydrocyanic acid and is transformed into an acetyl pentose.
Wohl forms the oxime and converts it into an acetylated nitrile by means of acetic anhydride and sodium acetate; ammoniacal silver nitrate solution removes hydrocyanic acid and the resulting acetate is hydrolysed by acting with ammonia to form an amide, which is finally decomposed with sulphuric acid.
The relationships existing between the various hydrophthalic acids may be shown as follows: - Dihydro (Trans.) Acetic anhydride A 3.5 Dihydro (Cis.) A.