Research Article

Intramolecular Lactonization of Poly(α-hydroxyacrylic acid): Kinetics and Reaction Mechanism

Table 1

Assignment of the 1H shifts (at intensity maximum) and their average deviations (ad) of the acyclic and lactonized structures of PHA at pH 1–9.

pHAcyclic PHA
ppm
adLactonized PHA
ppm
ad

12.18–2.260.04n/a–2.84n/a
22.17–2.240.04n/a–2.79n/a
32.18–2.240.032.53–2.780.13
42.10–2.220.062.47–2.680.11
4.52.07–2.200.072.44–2.670.12
52.03–2.130.052.47–2.620.08
61.98–2.000.012.42–2.460.02
71.97–1.990.01n/a-n/an/a
81.97–1.980.01n/a-n/an/a
91.97–1.980.01n/a-n/an/a