The hydrolysis of methacrylates in solutions of hydrochloric acid and sodium bicarbonate

Abstract

AbstractThe hydrolysis of methyl (I), dimethylaminoethyl (II), N‐methylanilinoethyl (III), 3‐ and 4‐dimethylaminobenzyl (IV and V), 2‐carboxyphenyl (VI), 2,2,2‐trichloroethyl (VII), 1,2,2,2‐tetrachloroethyl (VIII), 2‐(1,2,2,2‐tetrachloroethoxy)ethyl (IX) and 1‐(4‐chlorophenyl)‐2,2,2‐trichloroethyl (X) methacrylates in approximately 2.5% HCl and NaHCO3 solutions was investigated. In the mixture of hydrochloric acid and DMF, hydrogen chloride was substituted by formic acid due to the saponification of DMF. At 25 and 40°C, monomers (V), (VI) and (VII) were evidently hydrolyzed in this mixture, while the hydrolysis of other methacrylates within 96 h at 40°C could be neglected. In the mixture of hydrochloric acid and dioxane at 40°C, the pseudo‐first order rate constant of (I) is 6.0 ± 0.3 · 10−6 S−1; the hydrolysis of (II), (III) and (IV) can be neglected. In the mixture of hydrochloric acid and acetone at 40°C, the pseudo‐first order rate constant of (I) is 1.6 ± 0.2 · 10−6 S−1, while for (VII) k = 0.6 ± 0.1 · 10−6 S−1, and the hydrolysis of (X) is negligible. In an aqueous solution of NaHCO3 at 40°C, according to the second‐order equation the rate constant of hydrolysis of (VI) is 1.4 ± 0.2 · 10−5 dm3 mol−1 s−1.