CHEMICAL PROPERTIES OF FATTY ACIDS AND RELATED COMPOUNDS 145 



j.j(jg56o ^rgre obtained when thionjd chloride was used. All of the acid 

 chlorides from Cs to Cis have been prepared by the employment of this re- 

 agent. ^''^ Silicon tetrachloride has found an application in the synthesis of 

 butyryl chloride, ^^- as well as in that of several other lower fatty acids, ^®^ 

 but it is apparently not satisfactory for the preparation of the halides of the 

 long-chain fatty acids. 



Another procedure which can be used for the synthesis of the acid 

 chlorides involves phosgene, COCI2. When the acid vapors and phosgene 

 are passed over such a contact catalyst as charcoal at a high temperature,^®^ 

 or when the sodium salts are heated with phosgene in a closed vessel, ^^^ 

 the acid chloride results. The reaction can be effected with the higher fatty 

 acids by passing the fatty acid vapors and phosgene over charcoal^®® at 

 150 °C. or by bubbling phosgene through the fatty acid containing a tertiary 

 amine^" at 100 °C. Lauroyl chloride and palmitoyl chloride have been 

 prepared from the corresponding acids in 90 and 75% yields, respectively, 

 by this latter procedure. ^^^ 



Adams and Ulich'*^^ have reported that the higher fatty acids react al- 

 most quantitatively with oxalyl chloride, either directly or in a solvent. 

 Capro3d, capryl, lauroyl, myristoyl, and stearoyl chlorides have been 

 synthesized by the use of oxalyl chloride, ^^^ as well as a series of acid chlo- 

 rides of unsaturated acids (oleoyl, elaidoyl, linoleoyl, and linolenoyl chlo- 

 rides).*®" Acid anhydrides may likewise be used as a starting material 

 when oxalyl chloride is employed. 



b'. Properties of the Acid Halides: The acid chlorides of the fatty 

 acids with shorter chains than stearic acid are liquid at usual temperatures. 

 They can all be distilled without decomposition but, with the higher mem- 

 bers, this must be carried out under reduced pressure. As one might pre- 

 dict, the fatty acid halides are readily soluble in organic solvents; however, 

 when the solvent contains a replaceable hydrogen, the fatty acid halide 

 will react with it. One of the most striking properties is the pronounced 

 reaction with water, which results in the formation of the fatty acid and 

 hydrogen chloride. This takes place promptly with the lower members of 

 the series, and somewhat more slowly with the longer chain compounds. 



560 C. R. Noller and R. A. Bannerot, /. Am. Chem. Soc, 56, 1563-1565 (1934). 



5«i B. F. Daubert, H. H. Fricke, and H. E. Longenecker, ./. Am. Chem. Soc, 65, 2142- 

 2144 (1943). 



562 G. Rauter, Ann., 270, 235-266 (1892). 



663 R. E. Montonna, J. Am. Chem. Soc, 49, 2114-2116 (1927). 



66^ A. Hochstetter, German Patent No. 283,896 (Aug. 17, 1913). 



665 A. Hochstetter, German Patent No. 284,617 (Aug. 17, 1913). 



666 1. G. Farbenind., A.-G., Brit. Patent No. 515,963 (Dec. 19, 1939); German Patent 

 No. 687,670 (Jan. 11, 1940); Chem. Abst., 35, 5911, 3268 (1941). 



66- Soc. pour I'ind. chim. a Bale, Brit. Patent No. 540,096 (Oct. 6, 1941); Chem. Abst., 

 36, 4136 (1942). 



668 J. Prat and A. Etienne, Bull, soc chim. [5], 11, 30-34 (1944). 



669 H. P. Averill, J. N. Roche, and C. G. King, /. Am. Chem. Soc, 51, 866-872 (1929). 



