DETERMINATION OF PK VALUES OF SOME WEAK ACIDS IN LIQUID AMMONIA

The pK values of some weak acids were measured using the hydrogen electrode in liquid ammonia containing 0.1M potassium iodide supporting electrolyte at −60°C. The results showed that acetone (pK = 22.5), aniline (pK = 28.8), and 4-chloroaniline (pK = 27.4) were weaker acids than water (pK = 18.9), while thiophenol, diphenyl thiourea, thiocarbohydrazide (pK<2), phenol (pK = 3.5), phenylthio-urea (pK = 3.8), thioacetamide (pK = 4.6), thiosemicarba-zide (pK1 = 4.7; pK2 = 8.5), thiosinamine (pK = 6.6), diphenylurea (pK = 7.0), diphenylsemicarbazide (pK = 7.6), diphenylguanidine (pK = 10.7), and diphenylcarbazone (9.5<pK<11) were stronger than water. © 1969, Taylor & Francis Group, LLC. All rights reserved.