d- and l-Octanol-2 could be produced through the following synthetic routes.

(A) Preparation of sec.-Octyl Phthalate.—A mixture of 130 g. (1 mole) of sec.-octyl alcohol (p. 366) and 148 g. (1 mole) of phthalic anhydride is heated for twelve to fifteen hours in a flask surrounded by an oil bath at 110–115°. During the heating the mixture should be mechanically stirred or shaken occasionally to give a homogeneous liquid. The cooled reaction mixture is added to about 8 l. of water which contains 150 g. (1.4 moles) of anhydrous sodium carbonate. The solid material gradually goes into solution, and if the resulting solution is perfectly clear, dilute hydrochloric acid is added in slight excess, thus precipitating the sec.-octyl hydrogen phthalate as an oil which rapidly turns to a solid; if the alkaline solution is not clear, owing to the presence of methyl hexyl ketone in the original alcohol, it should be extracted with ether to remove the ketone before acidifying with hydrochloric acid.

The octyl hydrogen phthalate is filtered, washed with water, ground thoroughly with water in a mortar, and finally filtered and dried. For complete purification it may be crystallized either from petroleum ether (b.p. 60–70°) or glacial acetic acid, from which it separates as needles melting at 55°. The crude material, however, is perfectly satisfactory for the following experiments. The yield is nearly quantitative if the sec.-octyl alcohol is pure.

(B) Resolution.—A warm solution of 278 g. (1 mole) of sec.-octyl hydrogen phthalate and 600 cc. of acetone is treated with 394 g. (1 mole) of brucine and the mixture warmed until the solution is clear. Upon cooling, the crystals of brucine salt (A) form. These are filtered, pressed, and washed in the funnel with 250 cc. of acetone. The combined filtrate and washings are concentrated to about 50 per cent of their original volume and then poured into dilute hydrochloric acid (slightly more than the calculated amount), which causes the precipitation of the sec.-octyl hydrogen phthalate. After the precipitate sets to a crystalline mass, it is filtered, washed with cold water, and dried. This weighs approximately one-half of the original ester used and has a rotation [α]₅₄₆₁ − 47° in absolute alcohol solution.

The crystals (A) are dissolved in the minimum amount of hot ethyl alcohol and decomposed by pouring the solution into dilute hydrochloric acid. The weight of the ester thus obtained is about one-half of that originally taken, and its rotation in absolute alcohol is about [α]₅₄₆₁ +47°, [α]_D +44°.

The two lots of crude active sec.-octyl hydrogen phthalate are now separately crystallized twice from acetic acid (about 2 g. of 90 per cent acetic acid should be used for each gram of solid). They are thus obtained in an optically pure condition and possess the rotations [α]₅₄₆₁ − 58.5°, [α]_D − 48.4° and [α]₅₄₆₁ +58.3°, [α]_D +48.4°, respectively. The amount of pure product, m.p. 75°, obtained in each case is respectively about 99 g. and 96 g. (about 70 per cent of the theoretical amount). The sec.-octyl hydrogen phthalate of low optical activity obtained by adding water to the acetic acid filtrates can be collected and used in a subsequent preparation.

(C) Hydrolysis.—Optically pure l- and d-sec.-octyl alcohols are obtained by distillation in a current of steam of the sec.-octyl hydrogen phthalate and 2 moles of sodium hydroxide in 30 per cent solution. The alcohols are practically insoluble in water and are separated, dried with potassium carbonate, and distilled. Each boils at 86°/20 mm. and has a rotation [α]^17°5461 + 11.8°, [α]^17°D + 9.9° or [α]^17°5461 − 11.8°, [α]^17°D − 9.9°.  The yields of alcohol from the sec.-octyl hydrogen phthalates are about 95 per cent of the calculated amounts.