ACD/pK_a DB

The acid-base dissociation constant can be calculated using our pK_a software. For bulk calculation requirements, ACD/pK_a Batch is available for Microsoft Windows, Linux, and SUN platforms. To relate the acid-base dissociation constant to the partition coefficient at variable pH, please refer to our product literature on ACD/LogD Suite. To calculate the octanol-water partition coefficient for non-charged species (i.e., at pH values suppressing ionization) please refer to our product literature on ACD/LogP DB.

To find out which pK_a product is right for your needs, compare the presence of the following features:

Feature	pKa DB	pKa Batch
Maximum number of atoms per molecule	255 (excl. H)	255 (excl. H)
Allowed atoms	C, H, O, S, P, N, F, Cl, Br, I, Se, Si, Ge, Pb, Sn, As, B	C, H, O, S, P, N, F, Cl, Br, I, Se, Si, Ge, Pb, Sn, As, B
Number of permitted ionization centers	20	20
Calculates apparent pKa values (macroconstants)
Calculates single pKa values
Calculates current form pKa values (microconstants) for each ionization center		–
Allows algorithm training with your own data to improve accuracy: use customer's databases and ACD/pKa Accuracy Extender
Relates the calculated pKa values to the corresponding ionization centers in the polyelectrolyte structure and shows the predominant ionization forms		–
Displays uncertainty of the pKa prediction
Copies pKa ± pKa into report
Calculates statistical factor
Displays statistical factor		–
Reports a warning if no ionization center present
Structure input through ChemSketch window		–
Imports from molfile		–
Imports from Sdfile
Imports from ISIS database	–
Imports from ACD/ChemFolder database	–
Imports from SMILES text file	–
Able to automatically process pKa for a very large number of compounds at once	up to 999 at once
Other ACD/Labs products can be accessed through the ACD/Labs menu		–
Online help for pKa calculation available
Uses parameters derived from internal ACD/Labs database
Uses full power of a unique ACD/Labs algorithm
Create your own database		–
Access and search pKa databases according to sketched molecular structure or substructure, ionic strength, temperature, experimental pKa, molecular formula, molecular weight and other parameters		–
After calculating pKa, the program displays results along with experimentally-observed pKa values, compound name, temperature, ionic strength, and reference to scientific literature if compound is in the ACD/Labs internal database		–
Displays warning for molecules with different tautomeric forms, vinylology, and covalent hydration
Shows the pKa calculation protocol, i.e., which fragment contributed how much to pKa and pKa		–
Displays summary of all pKa calculations in a single session in History window		–
Reports the results of calculation
Exports the results of calculation to an SDfile
Exports the results of calculation to an RDfile, text file, or ACD/ChemFolder database	–