A. Tetrahydrofurfuryl chloride. In a 2-l. three-necked flask, fitted with a mechanical stirrer, a dropping funnel, and a thermometer, are placed 408 g. (4 moles) of freshly distilled tetrahydrofurfuryl alcohol (Note 1) and 348 g. (4.4 moles) of pyridine. To the rapidly stirred mixture, which is cooled in an ice bath, 500 g. (4.2 moles) of freshly distilled thionyl chloride (Note 1) is added from the dropping funnel at the rate of 3–5 drops per second. When one-third to one-half of the thionyl chloride has been added, a pasty crystalline mass begins to separate and the temperature begins to rise rapidly. The temperature should not be allowed to go above 60°. As more thionyl chloride is added the mass redissolves and a dark brown liquid forms. When the addition is complete, the bath is removed and the mixture is stirred for 3–4 hours. The liquid (or the slurry, if some crystallization has occurred) is poured into a beaker (Note 2) and extracted seven times with 500-ml. portions of ether (Note 3); the ether extracts are decanted and combined. The ether is removed by distillation, and the residue is washed three times with 100-ml. portions of water, dried over anhydrous magnesium sulfate, and distilled under reduced pressure. The yield of tetrahydrofurfuryl chloride boiling at 41–42° /11 mm. (47–48° /15 mm.) is 354–360 g. (73–75%).

B. 4-Penten-1-ol. A 2-l. three-necked flask containing 112 g. (4.87 moles) of powdered sodium (Note 4) under 700 ml. of anhydrous ether is fitted with a mechanical stirrer, a separatory funnel, and a reflux condenser with a drying tube. A few milliliters (2–3) of a mixture of 300 g. (2.5 moles) of tetrahydrofurfuryl chloride and 300 ml. of anhydrous ether is added to the rapidly stirred suspension. A vigorous reaction occurs, and the solution turns blue. The remainder of the solution of the chloride is then added dropwise over a period of 5 hours, during which time the flask is cooled in an ice bath (Note 5). When the addition is complete, stirring is continued for 2 hours. The suspension is decanted from any sodium that remains (Note 6) into a dry beaker and decomposed with sufficient ice water to give two liquid layers. The ether layer is separated and dried over magnesium sulfate. After the removal of the ether by distillation on a steam cone, the residue is distilled. The yield of 4-penten-1-ol boiling at 134–137° is 161–178 g. (76–83%).