ChIN简介页:ACD pKa, LogP, LogD, Solubility
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ACD pKa, LogP, LogD, Solubility


     Advanced Chemistry Development

     ACD/pKa DB:

ACD/pKa DB is a program that calculates accurate acid-base ionization constants (pKa values) under 25°C and zero ionic strength in aqueous solutions for almost any organic structure. ACD/pKa DB is an easy-to-use tool which enables you to:

Calculate the observed or macroscopic dissociation constants for organic and some inorganic chemical compounds (based on the choice of the dominant ionic form in the system at the equilibrium state) under standard conditions (25°C and zero ionic strength);

Calculate microscopic constants of dissociation of specific ionic forms which could be present in an equilibrium system.
Calculate single pKa values for all possible dissociation centers, when the rest of the molecule is considered neutral.

Train the system with experimental data of high degree of confidence in order to calculate more accurate pKa values.

Search the database containing more than 15,900 chemical structures with references to more than 23,000 experimental pKa values (DB version). Searching can be done by structure, by sub-structure, by molecular weight, by molecular formula or pKa value, by Reference(only for Internal DB), by IUPAC Name (only for Internal DB) and by User Data(only for User DB).

ACD/pKa DB has the following limitations:

It cannot calculate the pKa values for:

structures containing atoms other than C, H, O, S, P, N, F, Cl, Br, I, Se, Si, Ge, Pb, Sn, As, B;
structures containing elements in non-typical valence;
structures with non-covalent (coordinating) bonds;
structures containing more than 255 atoms;
structures containing more than 20 ionizable centres.
ACD/pKa does not take into account the specific features of different stereomers (R-, S- isomerism), conformers and isotopes.


ACD/LogP DB accurately calculates LogP (octanol/water partition coefficient) for the neutral form of a molecule-in most cases to ± 0.3 LogP units or better! The calculation is based on an algorithm which uses the experimental LogP values for over 12,400 structures with more than 1,200 different functional groups.

ACD/LogP DB's internal database contains 18,412 compounds with experimental LogP values collected from different sources. This is the largest compilation of logP values.


ACD/LogD Suite calculates logD values (the apparent logP at any pH value) for almost any drawn organic structure.

The ACD/LogD Suite enables you to do the following:

Calculate logD at any pH;
Calculate logD with or without taking into account ion-pair partitioning;
Present results both in table and graph form;
Determine the dominant ionic form of the chemical structure in the water-octanol mixture;
View the solution proportion of each ionic form as a function of pH;
Calculate the percentage of the dominant form in aqueous and organic phases;
Calculate the bioconcentration factor (BCF) at any pH.
Calculate the adsorption coefficient (KOC) at any pH; and
Specify the logP/logD database(s) to be used for system training.

ACD/Solubility DB

ACD/Solubility DB determines the aqueous solubility at 25°C of organic compounds for pH values from 0.0 to 14.0

The internal database of ACD/Solubility DB contains data from the AQUASOL DataBase by special license arrangement with Prof. Samuel Yalkowsky, College of Pharmacy, University of Arizona. The experimental solubility values for over 4,400 compounds are followed by the list of articles where they were reported.

  Advanced Chemistry Development (ACD)

Summary by 李晓霞 on 2002-11-04

Last updated by 李晓霞 on 2002-11-04

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