8异丁酰氯的合成.pdfVIP

DOI:10.15227/orgsyn.025.0058 Organic Syntheses, Coll. Vol. 3, p.490 (1955); Vol. 25, p.58 (1945). ISOBUTYRAMIDE Submitted by R. E. Kent and S. M. McElvain. Checked by C. R. Noller and D. Frazier. 1. Procedure A. Isobutyryl chloride . A 1-l. three-necked flask is equipped with a 250-ml. dropping funnel, an efficient stirrer sealed with a glycerol-lubricated rubber tube, and an efficient condenser (Note 1). The water supplied to the condenser is cooled to 0°, and the flask is cooled in a large water bath. The apparatus is set up in a hood, and a gas-absorption trap is attached to the top of the condenser. In the flask is placed 542 g. (4.55 moles) of thonyl chloride; to this is added dropwise, and with rapid stirring, 352 g. (4 moles) of isobutyric acid (Note 2). A vigorous evolution of hydrogen chloride and sulfur dioxide takes place. When all the acid has been added, the water bath is heated to 80° and is kept at this temperature for 30 minutes. Stirring is continued throughout the heating. The reaction mixture is then distilled through a 30-cm. Vigreux column by means of an oil bath heated on a hot plate (Note 3). The fore-run boiling up to 89° weighs 44 g. The isobutyryl chloride which is collected at 89– 93° weighs 351 g. The residue weighs 49 g. On combining the fore-run and residue and redistilling slowly, an additional 33 g. of isobutyryl chloride is obtained; the total yield is 384 g. (90%). Redistillation gives a faintly yellow product boiling at 90–92° (No