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Reaction rates for nucleophiles with cyanogen chloride: Comparison with two other digonal carbon compounds
Author(s) -
Edwards John O.,
Erstfeld Thomas E.,
IbneRasa Khairat M.,
Levey Gerrit,
Moyer Maria
Publication year - 1986
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.550180204
Subject(s) - chemistry , cyanate , nucleophile , reaction rate constant , hydrolysis , inorganic chemistry , hydroxide , hydrogen peroxide , chloride , kinetics , medicinal chemistry , catalysis , organic chemistry , physics , quantum mechanics
The hydrolysis kinetics of CICN have been reinvestigated from pH 0.0–10.5 and from 18–40°C. In the pH range from 1–5, the hydrolysis rate is invariant and the activation parameters (Δ H ‡ = 84 kJ mol −1 and Δ S ‡ = −84 J mol −1 K −1 ) are consistent with water attack. In basic solution the rate is first order each in CICN and OH − concentrations with parameters Δ H ‡ and Δ S ‡ equal to 82 kJ mol −1 and + 54 J mol −1 K −1 , respectively. The rate constants with 20 other donors have been measured. Nitrogen nucleophiles are more reactive than oxygen donors, and an alpha‐effect is seen. The constants follow a pattern indicative of attack at carbon. Cyanate in its acid form reacts with nucleophiles. Further points on the cyanate rate–pH profile have been obtained. A chromate‐catalyzed hydrolysis can contribute between pH 5–10. Some studies were made of the reaction of cyanate with hydrogen peroxide. Free energy correlations are presented.