A comparison of log Kow (n-octanol–water partition coefficient) values for non-ionic, anionic, cationic and amphoteric surfactants determined using predictions and experimental methods

Environmental Sciences Europe

Table 5 Summary of QSPR-predicted values used in comparison with slow-stirring log K_ow/D values for each surfactant tested

Log K_ow method	Non-ionic			Anionic^d			Cationic^d			Amphoteric^d
Log K_ow method	C8 EO4	C12 EO4	C12 EO8	C12 AS	C12E4S	C12 Carb	C12 TMAC	C16 TMAC	C18 BAC	C12–16 ADB^a	C12 AAPB	C12 DAO
Slow-stirring	2.64	4.33	3.96	1.92	1.47	3.15	0.68	1.83	1.32	3.69	2.59	0.71
KOWWIN	1.71	3.67	2.57	2.42	1.32	5.00	1.22	3.18	5.87	0.88	1.31	4.67
CLOGP	2.43	4.55	3.84	4.52	4.15	1.10	0.56	2.68	6.36	− 2.13	− 2.30	3.20
Molinspiration	2.42	4.40	3.62	1.78	1.06	2.32	1.84	3.87	6.47	− 0.97	− 2.25	3.27
H & L	2.77	4.93	4.53	1.60	2.27	1.10	2.14	4.30	5.77	NA	NA	NA
ALOGP	2.27	4.10	3.57	2.17	1.64	3.10	1.27	3.09	5.59	2.32	1.00	4.50
ACD Labs	1.85	3.97	2.54	5.40	4.33	5.03	0.67^b	2.40^b	4.28^b	0.66	0.32	3.27
Crippen F.	2.02	3.68	3.06	NA	NA	NA	NA	NA	NA	NA	NA	NA
Viswanadhan’s F.	1.87	3.45	2.79	NA	NA	NA	NA	NA	NA	NA	NA	NA
Broto	2.51	4.33	4.00	3.46	3.13	4.49	NA	NA	NA	NA	NA	NA
SPARC	3.50	5.50	6.45	NA	NA	NA	NA	NA	NA	NA	NA	NA
Mean QSPR log K_ow	2.39	4.26	3.70	3.05	2.56	3.16	1.28	3.25	5.72	0.15	− 0.38	3.78
Mean difference^c	− 0.31	− 0.07	− 0.26	1.13	1.09	0.01	0.60	1.42	4.40	− 3.57	− 2.97	3.07

NA not applicable. Method unavailable to generate a value for comparison
^aBased on weighted average for chain length distribution
^bPredicted value does not include counter ion in SMILES
^cDifference between QSPR prediction mean and slow-stirring result
^dValues used from ionised SMILES notations for direct comparison
Experimental slow stirring data are presented in italics in order to distinguish them from other QSPR predicted data