Acid Dissociation Calculator

Experimentally determined pK_a values can be used to train the GALAS algorithm even if you aren’t a computational chemist or software engineer. Improve prediction accuracy for proprietary chemistry with reliable pK_a measurements.

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Classic Algorithm

The internal training database is made up of >20,000 compounds, representing >35,000 pK_a values.

Hammet-type equations for popular ionizable functional groups and carefully derived electronic substituent constants (σ) are used to predict the most accurate pK_a values.

Tautomeric equilibria, covalent hydration, resonance effects, and α, β-unsaturated systems are taken into consideration in the calculations.

GALAS Algorithm

The GALAS model is Global, Adjusted Locally According to Similarity. The internal training set contains >17,500 compounds representing >20,000 ionization centers.

A database of ionization centers, interaction constants, and interaction calculation methods are used to simulate a complete distribution plot and produce a full range of protonation states of the molecule at different pH conditions. pH dependency of net molecular charge, distribution of protonation states, and the average charge of each ionization center are provided.

pK_a (the acid dissociation constant) describes the inherent property of a compound or ionizable functional group to lose H⁺ and generate hydronium ions (H₃O⁺).

pH measures the concentration of hydronium ions (H₃O⁺) in aqueous solution

pH = -log [H₃O⁺]

Download this document to Learn all about the acid dissociation constant (pK_a)

Synthetic chemists use the acid dissociation constant to understand what substances can be used to protonate or deprotonate a compound, to assist a reaction. In biochemistry, pK_a helps scientists understand the activity of enzymes and the stability of proteins.

In pharmacology, the ionization of a compound changes its physical behavior and affects macro properties such as aqueous solubility and lipophilicity. pK_a values are also used to understand more complex ADME characteristics.

pK_a is used by chromatographers to select the appropriate pH of the mobile phase (buffer) for separations.

In environmental sciences, acid-base equilibria of humic acids help establish the potability and treatment of water and provide information about the health of waterways such as lakes and rivers.