Conductance Studies of Aqueous Succinic Acid

Abstract

Conductance measurements of aqueous solutions of succinic acid and of di-sodium succinate were performed from 278.15 to 308.15 K and the limiting conductances A 0 (1/2 Succ 2-) are reported. The Waiden product is independent of temperature: A 0 (1/2 Succ 2~) • >/(T) = 0.503 ± 0.001. The salt conductances closely obey the Onsager limiting law. The evaluation of the equilibrium constants for the primary and secondary steps of dissociation, K l and K 2 , and the limiting conductances of the hydrosuccinate ion, (HSucc -), are discussed using the Quint and Viallard conductance equation.

Ion Pairing and Solvent Relaxation Processes in Aqueous Solutions of Sodium Malonate and Sodium Succinate

“…A plot of τ 1 -1 against I (not shown) is linear at c < 0.4 M, which indicates the formation of only one ion-pair type. The slope of this plot gives k 12 = (2.9 ± 0.3) × 10 9 L·mol -1 ·s -1 , which is 1/9 of the diffusion-controlled limit estimated from the limiting anion conductivity . Combination of this value with yields k 21 = (3.4 ± 0.5) × 10 8 s -1 , which corresponds to an ion-pair lifetime, τ L = (ln 2)/ k 21 = 2.0 × 10 -9 s, about 18 times larger than expected for diffusion-controlled decay .…”

“…The slope of this plot gives k 12 ) (2.9 ( 0.3) × 10 9 L‚mol -1 ‚s -1 , which is 1/9 of the diffusion-controlled limit estimated from the limiting anion conductivity. 31 Combination of this value with K°A yields k 21 ) (3.4 ( 0.5) × 10 8 s -1 , which corresponds to an ion-pair lifetime, τ L ) (ln 2)/k 21 ) 2.0 × 10 -9 s, about 18 times larger than expected for diffusion-controlled decay. 30 The value of τ IP rot ≈ 250 ps roughly conforms with the expected rotational correlation time of an SIP.…”

An Analysis of Electrical Conductances of Aqueous Solutions of Polybasic Organic Acids. Benzenehexacarboxylic (Mellitic) Acid and Its Neutral and Acidic Salts

“…Because conductivities of citric acid and neutral citrates were only determined experimentally, the limiting conductance of the intermediate ion, λ 0 (1/2HCit 2- ), was evaluated with the help of the Pethybridge empirical rule (this limitation was later removed). The model was successfully applied to 1:2 systems, i.e., to dibasic acids and related salts (succinic acid, malonic acid, tartaric acid, − and oxalic acid) and to 1:3 systems (phosphoric acid and neutral and acidic phosphates).…”