Prediction of environmental parameters by adsorbability index: Water solubilities of hydrophobic organic pollutants

Environment International, Vd. 18,pp. 249-261,1992

0160-4120/92$5.00+ .00 Copyright© 1992PergamonPressLtd.

Printed in the U.S.A.All fightsreserved.

PREDICTION OF ENVIRONMENTAL PARAMETERS BY ADSORBABILITY INDEX: WATER SOLUBILITIES OF HYDROPHOBIC ORGANIC POLLUTANTS

S. Okouchi, H. Saegusa, and O. Nojima Chemistry Laboratory,Collegeof Engineering,HoseiUniversity,Koganei,Tokyo184 Japan

E19107-162 M (Received22 ]uly 1991; accepted28 December 1991)

The adsorbability index proposed by Abe et al. to predict the activated carbon adsorption of organic compounds from aqueous solutions was found to be an effective parameter for predicting the water solubilities of 265 hydrophobic organic pollutants which were classified into 118 aliphatic compounds and 88 mono- and 59 polynuclear aromatic compounds; and, furthermore, for predicting the total molecular surface areas of these compounds.

INTRODUCTION The adsorbability index (AI) was recently proposed by Abe et al. (1986) from a quantitative structure activity relationship analysis based on the molecular refraction to predict the activated carbon adsorption of 157 organic compounds from aqueous solutions (Freundlich adsorption constant: K). The linear relationship between log K and AI gave a good correlation coefficient of 0.986. In our previous paper (Okouchi 1989), the adsorbability index was reported to be applicable for predicting a soil sorption coefficient of 72 hydrophobic organic compounds as a quantitative measure of soil adsorption, as well as the activated carbon adsorption. In this paper, it was attempted to investigate whether the adsorbability index was applicable to predict the water solubilities of 265 hydrophobic organic compounds (Nirmalakhandan and Speece 1988a; Kishi et

al. 1987; Mackay et al. 1980; Pearlman et al. 1984; Yalkowsky and Valvani 1980; Mackay and Shiu 1981; M a l l h o t and P e t e r s 1988) such as p o l y n u c l e a r aromatic hydrocarbons, halogenated benzenes and biphenyl, and halogenated alkanes and alkenes. The water solubilities have been reported to be correlated with the total molecular surface areas (TSA) by many researchers. Then, the water solubilities calculated from the adsorbability index were compared with those from the total molecular surface areas.

RESULTS AND DISCUSSION The adsorbability index (AI) of a given molecule can be readily calculated from Eq. 1 (Abe et al. 1986) by adding the values of A and I (Table 1). AI = A + I

249

(1)

250

S. Okouchi et al.

where A and I indicate the factors of the respective increasing and decreasing adsorbabilities of the atom or functional group in the molecule onto the activated carbon from aqueous solution. The AI values calculated from Eq. 1 are shown in Table 2 for 265 hydrophobic organic compounds. The AI vahaes m Table 2 are obtained by only the A values, since th~ I v a l u e , can b e ignored for the hydrophobic compounds used'in this work. The regression analysis showed that the relationships between the logarithm of water solubility (log S) and AI or TSA of the 265 compounds can be expressed as the following linear functions: log S = -0.855 AI - 0.004 mp - 0.026 (n = 265, r = 0.939, s = 0.778)

(2)

log S -- -0.029 TSA - 0.009 mp + 1.321 (n = 265, r = 0.970, s = 0.550)

(3)

where S is the water solubility (reel/din3), mp is the melting point (°C), n is the number of compounds, r is the correlation coefficient, and s is the standard deviation. The TSA in Table 2 was calculated using a modified Monte Carlo method by Kishi et. al. (1987). The water solubility of a crystalline hydrophobic solute can be described using the term of melting point and entropy of fusion with the term of activity coefficient. Therefore, for liquids below 25"C, where the entropy term does not apply, mp is assigned a value

of 25. Their results indicated that Eq. 3 predicted by TSA was superior to Eq. 2 by AI (Fig. 1). Then, the relationship between AI and TSA for all 265 compounds was evaluated as shown in Fig. 2a and Eq.4. T • A = 26.50 AI + 52.70

Figure 2a, however, seemed to consist of three linear functions rather than the only one regression e q u a t i o n in Eq.4. The three linear f u n c t i o n s corresponded to the three kinds of compound groups in Fig. 2b (the aliphatic compounds and the two aromatic compound groups of respective mono- and poly-nuclear compounds) as follows: for the aliphatic compounds such as alkanes and alkenes, and their halogenated compounds (n = 118) TSA

(5)

= 43.21 A I + 8.79

(r = 0.978, s = 10.22)

for the mono-nuclear aromatic c o m p o u n d s such as bonzenes and biphynyl, and their halogenated compounds (n = 88) TSA = 31.72 AI + 23.04 (r = 0.993, s = 6.66)

Table I. Adsorbability index.

A C H N O S F

Cl Br !

NO~ C=C C=C iso tert cycle

a) e t h e r

I O. 2 6 0.12 0.26 O. 1 7 0.54 0.13 0.59 0.86 1.35 0.21 0.19 0.26 -0. 12 -0. 32 -0. 28

(4)

(n = 265, r = 0.957, s = 17.90)

a lipha OH 0,) N ClIO CO CO011

tio

COOR aromatic OH, 0" , N, CO, COOH,

-0. -0. -0. -0. -0. -0. -0.

53 36 58 25 25 30 03

-0.

28

O. O 0

COOR e--alni n o acids

-I.

55

(6)

Solubility of organic pollutant=

251

Table 2. Water Iolubilides of 265 hydrophobic organic compounds.

COfli'OUNO hexadecane tel~l'adecane dodecane undecane n-decane pentylcyclopentane 4-111ethyl oc Lane n-nonane n-ocl.ane 3-methyl heptane 2,2,5- tl" ilae Lhyl hexatm 2,3,4- tr imethyl pentane hexachloro-I ,3-butadiene propylcyclolmntane 2,2,4- tr itnethyl pentalm l-octene 2-tnethyl hexalm 3-methyl hexalle n-heptane I, 1,3- trimel.hylcyclopetltane tratm- l, 4-d ime thy I cycl ohexane 2,4-dime thylpel~tane 2,2-dime thylpet~tane 2,3-dimethylpentane 1-c i s-2- d line thylcycl ohexane 3,3-d inle thy I petltane hexachloro- l - propyl elle ii- hexane methylcyclohexane 3-umthyl pentane trans-2-heptene 2-1uethyl pentane hexachloroethane 2,2-d i,le thyl bu Lane 2,3-dimet.hylbutane 2,2-dime thylpropane met.hylcyclopentane n-pentane

log S

-8.400 a) -7.960 a) -7.700 a) -6.551 a) - 6. ~,37 a) -6.086 a) -6.047 a) -6.022 a) -5,238 a) -5. 159 a) -5.047 a) -4.924 a) -4.803 b) -4.740 a) -4.670 a) -~,.619 a) - ~,.596 a) -4.579 a) -4.534 a) -4.478 a) -4.466 a) - b,.392 a) -4.357 a) -4.281 a) -4.272 a) -4.227 a) -4.165 b) -3.958 a) - 3.8t16 a) -3.828 a) -3.816 a) -3.795 a) -3.675 b) -3.671 a) - 3.65ll a) -3.337 a) -3.302 a) -3.273 a)

mpr*cl

25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25

AI 8.27 7.24 6.24 5.74 5.24 4.62 4.62 4.74 4.24 4.12 4.30 3.88 4.96 3.66 3.80 4.19 3.62 3.62 3.74 3.28 3./18 3.50 3.42 3.50 3.48 3.42 4.51 3.211 3.10 3.12 3.69 3.12 4.06 2,92 3.00 2.42 2.60 2.7~,

TSA[~2"I h)

Ill

359.4 317.6 275.8 254.9 234.0 211.5 215.6 213. I 192.2 194.7 220.7 199.7 197.6 169.7 199.8 186.3 173.8 173.8 171.3 174.8 172.2 176.3 176.4 176.3 172.2 176.4 186.2 150.4 148.8 152.9 165.1 152.9 176.0 155.5 155.4 1311.6 127.9 129.5

1 1 1 1 I l l I I 1 1 1 0 0 1 1 1 i 1 1 1 i l 1 1 1 0 1 1 1 1 1 0 1 1 1 1 1

252

S. Okouchi et al.

Table 2. Continued.

COI'II'OUHD

log S

tl-me thy I - I - pen I.ene

mp["C]

i sobu tane

-3.244 -3.226 -3.185 -3 179 -3 140 -3 121 -3 075

t.e t rachl oroe l.hyl erie

-3 044 b)

2- J11eLyhy I - I -pen tene

1, i , 2 , 2 - t . e trabromoe thane

-3 033 -2.976 -2.959 -2.877 -2.849 -2,732 -2.730 - 2.706 -2.705

a) a) c) b) a) a) b) a) b)

2,3 - d i ch I o ro- 2-,le thy I - a- bu La ne

-2.693

t,)

l - pen Lene

-2.676 -2.699 -2.653 -2.631 -2.631 -2.607 -2.581 -2.538 -2.506

a) c) a) b) b) b) b) a)

1 -hexene cyc I ohexane i sopentane te Lrabromoel.hane I - c I l l o r o - n- hexane

n- bu I,a:~e i od obu ta ne 1 -b rol, o- 3- me t.hy I - n- bu Lane i)1"op,'tlle 3-me I,hy I - i - I:,u Lene 1 -ch l o r o - n- pen Lane ethane

15 hexadiene cyc I opet~ Lane 2- c h l o ro -n-pen Lane 3-chloro-n-penl.ane pen Lachl oroe I.hane 2,3 - d i ch I o ro - n-bu t.a ne cis-2-pentene 2- c h I o t o - 2- I~lethy I - n- bu Lane 1 - b romo- 2-muet,hy I propane l,l-dichloro-n-bu

tane

1 - b rolllobu tane 1 - bu Lene 1,2-dibrolno-3-chloropropane e l.hene d i i odolile Lhane 2-,le l.hy I propene p r o pelle te Lrach I o rolue thane I,I,I,2-

t e t r a c h l o r o e l , hane

1 -c h l o r o -n-bu l,ane 1,2-d i brolllOl) ropane

-2.428

a) a) a) a) b) b) a)

b) b)

-2.405 b) -2.¢04 b) -2.~03 a) -2.373 -2.338 -2.337 -2.329 -2.323 -2.289

b) a) c) a) a) b)

-2.184 b) -2.178 b) -2.153 b)

25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25

AI

TSA[~. 2] h)

III

3.07 3.19 2.72 2.62

147.0 144.5 125.4 132.0

I

3.70

149.4

3.71 2.12 3.07 3.07 2.211 3.~17 3.36 1.74 2.57 3.21 1.21t t1.20 3.56 2.69

166.9 lll.l 127.8 157,0 108.6 141.1 156.6 87.7 126.1 146.0

0 0

I

l I

I 0 l 1 0 0

1 I

66.8

0 0

170.2 170.1 123.6

0 0 1

3. ltl

138.6

0

2.22 3.21 3.21 3.59 3.18 2.69 3.09 2.86 3.18 2.98 2.19 3.69 1.19 3.20 2.07 1.69 2.62 3.12 2.71 3.22

104.5 148.5 148.5 156,9 II16.6 123,3 151.1 135.7 ltltl. 1 133.2 102.7 155.9 61,2 110.9 103.3 81.8 117.0 137,9 125.1 139.4

I 0 0 0 0 1 0 0 0 0 I 0 1 0 1 1 0 0 0 0

Solubility of organic pollutants

253

Table 2. Continued.

log S

COI'IPOUND l,¢-pentadiene l.ri chl o r o e t h y I ene I, 3 -di bromopr opane cis-l,3-dichloro-

l-propylene

2-me thy I - I, 3 - bu tad i erie l - c h I o ro - 2- me I;hy I p ropa ne 2- chl o r o - n - butane 1,1,1- trichlvroethane 1 , 2 , 3 - t r i chl o rOl) rol)ane bu tatl iene Lri bi'omomethane

1, I -d i ch I oroe thyl ene 1,1,2,2- t e t r a c h l o r o e t h a n e 1 - b romop ropane 1,2-dibromoethane 1,3-dichloropropane l ,2-dichloropropane i odoe thane 2- b r OmOl)ropane 1,1,2-Lrichloroethane l-chloropropane cis-l,2-dichloroethylene 3-chloro- l-I)ropylene 2- chl o rol) r Opalle chl oroe t hy I ene

1- l.iroluo- 2-chl oroe thane cis-l.2-dibromoethylene l,l-dichloroethane 1 - blJ [.ylle d i b romometlmne Lrichloromethane 1,2-d i ch I oi'oe thane chloroethane propyne bromoe thane i odonie thane

bromoch I orome thane chl orome thane d i c h I o ro me ~.hane bromome ~,hane

-2.087 a) -2.078 b) -2.075 b) -2.045 b) -2.026 a) -2.000 b) -1.966 b ) -1.949 b) -1.890 b) -1.867 a) -I.857 b) -1.784 b) -1.754 b) -1.705 b) -1.655 b) "1.618 b) -1.606 b) -1.602 c) -1.600 b) -1.483 b) -I.472 b) -1.443 b) -1.427 b) -1.426 b) -1.355 b) -1.322 b) -1.320 b) -1.316 b) -1.2q2 a) -I.182 b) -1.178 b) -I.060 b) -I.055 b) -1.041 a) -i 026 b) -1 007 c) -0 942 b) -0 909 c) -0 814 b) -O 795 b)

mp[°C]

AI

TSA[.~. 2] h)

III

25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25

117.7 110.7 136.9 114.5 118.3 127.6 127.6 121.4 139.7 96.8 122.2 94.5 137.8 112.3 116.0 120.7 123.2 99.3 114.8 118.8 104.2 93.6 98.3 106.7 77.4 107.9 109.8 102.3

O 0 O 0 1 0 0 0 0 1 0 0 0 O 0 0 0 0 0 0 0 0 0 0

25 25 25

2.64 2.60 3.22 2.63 2.52 2.59 2.71 2.65 3.15 2.14 2.96 2.13 3.12 2.48 2.72 2.68 2.68 2.47 2.48 2.65 2.21 2.13 2.16 2.21 1.66 2.45 2.67 2.18

25

2.02

96.5

0

25 25

2.22 2.15

95.1 97.9

0 0

25 25

2.18 1.71

99.8 83.3

0 0

25 25 25 25 25 25 25

1.53 1.98 1.97 I .95 I .21 1.68 1.48

75.6 91.4 78.4 87.0 62.5 78.9 70.5

0 0 0 0 0 0 0

25

0

0 0 0

254

S. Okouehi et al.

Table 2. Continued.

COMPOUND

log S

mp['C]

AI

benzene f luorobenzene

- 1.6,1 d) -1.79 e)

25 25

2.85 2.86

109.5 114.6

l,'1-di f luorobenzene

-1.97 e)

25

2.87

118.2

1,2-difluorobenzene 1,3-difluorobenzene to I uene ch I orobe nzene s£yrene bron~obenzene e thy I benzene 1,2-d lute thyl benzene 1, ~,-d i me I,hy I benzene 1,3-d ime thy I benzene iodobenzene i , 2-d i chl orobenzene 1,3-d i chl orobenzene 2- b romoc h I o ro benzene 1- e thy I - 2- me thy I benzene 1,1', -d ich I orobenzene 3- b ronioc h I oro benzelle i sop ropy I benzene propy I benzene 1,2,3- t,r ime t,lly I benzene 1,3- d i br omobe nzene 1,2, ,1- t r i liie thy I be nzene 1,2- d i bronlobenzene 2-chloroiodobenzene 3-chl oro i odobenzene

-2.00 -2.00 -2.24 -2.37

e)

25 25 25 25

2.87 2.87 3.35 3.32

117.8 117.8 130.6 127.9

-2.54 c)

25

3.80

143.3

-2.64 -2.75 -2.79 -2.83

e) e) e) e)

25 25 25 25

3.59 3.85 3.85 3.85

134.3 150.3 147.3 150.8

-2.86 e)

25

3.85

151.2

-2.95 e) -3.02 e) -3.09 d) -3.19 d) -3.21 e) -3.21 d) -3.21 d) -3.34 b) -3.36 e) -3.38 e) -3.38 e) -3.49 e) -3.50 e) -3.5,1 d) -3.55 d) -3.58 e) -3.63 d) -3.72 d) -3.76 c) -3.99 e) -4.03 d) -q.07 e) -4.11 e) -,1.2,1 e) -,1.32 e) -,1.50 e) -,1.56 d)

25 25 25 25 25 53 25 25 25 25 25 25 25 25 25 25 68 25 25 25 57 89 53 40 25 44 92

4.08 3.79 3.79 4.06 4.35 3.79 4.06 4.35 4.35 4.35 4.33 4.35 ,1.33 ,1.55 4.55 ,1.35 4.06 ,1.26 4.73 ,1.85 ,1.55 ,1.33 4.26 5.31 5.,16 5.07 ,1.82

142.8 143.3 144.7 148.0 163.1 144.7 150.6 172.6 168.5 163.7 156.8 166.6 153.5 156.1 159.5 170.1 150.6 160.2 19~.1 187.4 159.5 157.7 158.7 167.6 192.8 176.8 165.5

1,3,5- tr inle thyl benzene ,1- bronlochl orobenzene 1,2,q- t r i c h l o r o b e n z e n e o - c yllle rle butylbenzene ,1- c h lo ro i odobenze ne 1, ,1- d i bro~nobenzene 1,2,3- t,r i chl o robenzene l , 2 -d i i odobenzene bi phenyl I, 2,,1- t r i b roHiobenzene tl- b rolno i odohe nzene

e) e)

e)

T S A [ ~ e] h)

III

Solubility of organic pollutants

255

Table 2. Continued. CONPOUNO

1,3- d i i odobenzene pen tyl benzene i , 3 , 5 - t r i chl orobenzene 2-chlorobiphenyl 1,2,3,4- t e t r a c h l o r o b e n z e n e (I i Idleny I me thane 1,2,3,5- te Lrach I o robenzene 3-chlorobil,henyl he×y I benzene 2,4-dichlorobiphenyl I,Ll-d i i odobenzene II-chl orobi phony I 2,2'-dichlorobiphenyl 2,q'-dichlorobiphenyl 2 , 5 - d i chl orob i phenyl 1 , 3 , 5 - t r i b romobenzene 2,2',5- trichlorobiphenyl 1 , 2 , 4 , 5 - te trach I o robenzene pull tach I orobenzene 2,11 ,ll' - t r ichl orolJ i phenyl 2,2',3,5- tetrachlorobiphenyl 2 , 4 , 5 - t r i c h l o r u b i pheny I 2',3,~l-l.richlorobiphenyl 4,4 ' -d i c111orol) i pheny I 2,2',~1,q'- tetrachlorobiphenyl 2 , 3 ' , 4, q' - te t rach I orob i pheny i 2 , 2 ' , 5 , 5 ' - te t rach I o rob i pl~eny I 2 , 3 ' , I!', 5- te t. rach I o rob I pheny I 2 , 2 ' 3 , 3 ' - te I,rachl orobi pheny I i , 2, q, 5- t.e Lrach I o rob i p he=ly I 2 , 3 , I1,5- te t rachl o rob i pheny I 3,a1,11' - t r i chl orob i pheny I 2,2' 3,4, G-pen tach Iorob i phenyl 2,2',3,4,5-pentachlorobiphenyl 2 , 3 , 4 , 5 , 6 - p e n tach Iorob i phenyl hexach I o robenzene 2 , 2 ' , 3 : 4 , 5 ' - peii tachl orobi phenyl 2,2',~,5,5'-pentachlorobiphenyl 2 , 2 ' , 3 , 3 ' , 5,6- he.~achlorob i pheny I 2,2',4,4',5,5'-hexachlorobiphenyl

log S

- 4.57 -4.59 -4.62 -4.66 -11.70 - 4.75 - 5. O0 -5.16 - 5.20 -5.20 - 5.25 - 5.32 -5.45 -5.50 - 5.59 - 5.60 -5.61 - 5.8~ - 6.00 -6.00 -6.24 -6.4/1 -6.52 - 6.60 -6.63 - 6.70 - 6.80 - 6.85 -6.93 - 6.98 - 7.18 - 7.23 -7.43 -7.52 -7.68 -7.76 -7.86 -7.89 -8.45 -8.48

e) e) e) e)

d) c) e) f) e) f) d) e) e) e) e) e) e) e) e) e) e) e) f) e) f) f) f) f) f) e) e) e) e) e)

e) d) e) e)

e) e)

mp['C]

AI

25 25 68 34 47 25 55 25 25 25 132 78 61 43 25 122 44 140 86 57 47 78 60 149 41 128 87 104 121 182 92 88 100

5.31 5.35 4,26 5.93 4.73 5.96 4.73 5.93 5.85 6.40 5.31 5.93 6.40 6.40 6.40 5.07 6.87

173.4 206.3 162.9 208.8 173.8 210.7 176.1 210.1 225.2 226.0 174.3 209.5 224.4 225.9 226.1 179.3 241.7

4.73 5.20 6:87 7.34 6.87 6.87 6.40 7.34 7.34 7.34 7.34 7.34 5.81 7.34 ~.87 7.81 7.81 7.81 5.67 7.81 7.81 8.28 8.28

175.7 188.9 242.5 257.0 240.8 241.6 226.5 259.6 259.2 259.6 259.2 255.6 190.0 254.2 241.9 270.4 269.8 268.2 203.0 272.0 271.4 284.8 286.3

100 124 230 112 77 I00 103

TSA[~, ~] h)

III

256

S. Okouchi et al.

Table 2. Continued.

COMPOUND

tog S

3,3' 2,2' 2,2' 2,2' 2,2' 2,2'

,tl,q'-tetrachlorobiphenyl ,q,~l ' ,6,6'-hexachlorobipherlyl ,3,3' ,q,5-hexachlorol}iplmnyl ,3,4' ,5,5' ,6-heptachlorobipllenyl ,3,3' ,4,4' -hexaclllorobildleriyl ,3,3' ,4,4' , 5 , 5 ' - o c t a c l l l o r o b i p h e n y l 2,2' ,3,3' ,5,5' ,6,6'-oct, aclllorobi pheriyl 2,2' ,3,3' ,4,4' , 5 , 5 ' ,6-nonaclllorobiphenyl

-8.59 -8.60 -8.62 -8.81 -8.92 -9.20 -9.38 -9.62

e) e) e) e) e) e) e) e)

benzo[b] thiophene indan naph Lha I erie 1-me Lily I naphtha I ene 2- me thy I naphtha I erie d i phenyl ether d i phenyl me thane I, 4- d ime Lhy I tm ph tha I etle I -e Lhy I naph l.ha l erie 1,3- dime t hy I na pll Lha I erie 2-e Lhylna ph Lha l ene a.eenaph lhene b ibenzy I I, 5- dime thy Inaph LIml erie 2,3- d i lue Lhy I naph [.ha I erie 2,6- d i inertly I naph Lha I ene 1, zi, 5- Lrime t,hy Inap h Lhal erie f I.orene pllenan I,hrerie 4,5- dime LIw I enepherlarl th i'ene d i benzoth iophelle 1 -sitethy I phermr~ klwene 9-the Lhyl a n I.hracene FIuo ran thene pyretle all I;h racene 9,10 -d ime Hlyl all I,h r acelle 6-me Lily I cllrysetle 5-me Lhyl cllrysene 7,12-d ime Lhyl benzo[a]an thracene

-3.01 g) -3.03 d) -3.60 d) -3.71 d) -3.75 d) -3.97 g) -4.07 g) -4.14 d) -4.16 d) -4.29 g) -4.29 d) -4.59 d) -4,62 g) -4.68 d) -4.79 g) -4.89 d) -4.92 d) -4.93 d) -5.15 d) -5.24 g) -5.25 g) -5.85 g) -5.87 d) -5.90 d) -6.18 d) -6.38 d) -6.57 d) -6.57 g) -6.59 g) -6.63 g)

mp['C]

AI

180 114 85 149 150 159 162 206

7.34 8.28 8.28 8.75 8.28 9.22 9.22 9.69

257.3 289.7 282.8 303.3 284.8 315.5 321.9 329.4

4.10 4.11 4.51 5.01 5.01 5.63 5.96 5.51 5.51 5.51 5.51 5.27 6.46 5.51 5.51 5.51 6.01 5.72 6.17 6.43 6.67 6.67 6.67 6.86 6.88 6.17 7.17 8.33 8.33 8.33

146.9 151.5 155.8 174.1 176.8 202.1 214.2 190.6 188.3 193.4 199.9 175.0 237.0 190.6 194.1 197.7 201.9 193.6 198.0 204.0 217.1 217.1 215.1 218.0 213,0 202.2 228.0 259.3 253.7 266,0

32 25 80 25 34 28 25 25 25 25 25 96 52 81 102 108 25 116 101 115 119 119 82 111 156 216 182 161 118 122

TSA[,~,2] h)

III

Solubility of orsani¢ pollutants

257

Table 2. Continued.

COI'IPOUNI)

log S

1 -,,e tllyl benzo[a]a n thracene ! 2-me thy I benzo[a]an thracene benzo[a] f I uorene 2 -me thy I on thr acene Lri I}hel~yl erie 9,10-benzophenan threne 7- e thy I benz~[ a]an thi'acene 5,6-d itlle thyl chrysene benzo[a] an Lhr acene L,enzo[ b] f I uorene 7-me LilyI bel,zo[a]an thracene d i benzo[ a, j ]an Lilt"acene 12- buty I I]enzo[a]an thracene benzo[e] py rene be n zo[a] pyrene benzoic] py rene cho I an th rene 4,5-d ime thyl enebenzo[b]an thracene benzol j ] f luora thene chr ysene 3-me thy I chol an th r ene berlzo[I,] r luoran th rene IJcll20[ k] f luoran Lhrene 6-me LilyI benzo[a]l,yrene naph thac erie benzo[g, h, i ] p e r y l ene d i benzo[a, h]a n th racene perylene coroilene

a) b) c) d) e) f) g) h)

= = = = = = = =

-6.64 -6.68 -6.68 - 6.69 -6.73 -6.75 - 6.80 -7.01

-7.21 -7.28 -7.35

-7.37

g) 8) g) d) d) c) g) 8) g) d) g) g) g)

-7.52 -7.60 g) -7.80 g) - 7.82 d) -7.85 g) -7.96 g) -8.00 g) -8.06 d) -8.08 g) -8.22 g) -8.52 g) -8.52 g) - 8.69 d) -8,70 g) -8.70 g) -8.80 d) -9.33 g)

InpI"'C']

AI

139 138 187 209 119 198 113 128 160 209 141 197 97 178 179 175 173 234 166 255 179 168 217 216 357 278 267 277 360

8.33 8.33 7.38 6.67 7.83 7.83 8.83 8.83 7.83 7.38 8.33 9.49 9.63 8.54 8.54 8.54 8.59 8.59 8.54 7.83 9.09 8.54 8.54 9.04 7.83 9.25 9.49 8.54 9.96

TSA[X ~] h)

257.9 253.3 237.4 222.6 236.0 236.0 280.8 267.8 244.3 239.9 258.3 286.5 326.2 251.5 255.6 251.5 269.2 269.3 259.7 241.0 291.0 260.8 265.0 269.6 248.0 266.9 286.5 251.5 282.4

III

-

-

reference Mackay and Shiu 1981; reference Nirmanlakhandan and Speece 1988a; reference Mallhot and Peters 1988; reference Yalkowsky and Valvani 1980; reference Kishi et al. 1987; reference Mackay et al. 1980; reference Pearlman et el. 1984; calculated from reference Kishi et el. 1987.

for the polynuclear aromatic compounds such as naph. thalene, anthracene, and pyrene (n = 59) T S A = 24.29 AI + 55.29 (r = 0.975, s ffi 8.69)

C7)

The classification of c o m p o u n d s gave a good correlation for the relationship between T S A and AI. Then, for the three c o m p o u n d groups, the prediction of water solubilities were reexamined using the f o l l o w i n g regression equations:

258

$. Okonchi et ,,1.

0 -2

-

l=uO

o

,.---I

-4

~~'~~°-14!

(TSA)

-6

,--'-4

-i

-8

j

e~

o

-10 -12 -12

-I0

-8

-6

-4

-2

0

c., -10~-12 -12

-I0

Observed logS

-B

I

I

-6

-4

I

-2

0

Observed logS

Fig. la and b. Relationship between log S observed and log S calculated from Bqs. 2 and 3 by respective AI and TSA methods for 266 compounds.

400

400

o ,~J

(a)

o =° Z

300 -

0

300 0

0 v

c~ °

200 -

200 C.wr~

100

I00 0

0

0

2

4

6

B

10

12

0r 0

I 2

f 4.

i 6

AI

AI Fig. 2a and b. Relationship between TSA and AI.

i 8

i 10

12

Solubility of organic pollutants

-2 0

239

-2 -

(AI) 0

-4

-4.

(W

m

-6

-6 -8

,---4

-8

r._)

-10

-10 -12 -12

-10

-B

-6

-¢

-12 -12

-2

-8

-10

Observed logS

-6

-4

-2

0

Observed logS

Fig. 3a and b. Relationship between log S observed and log S calculated from Eqs. I0 and I I by respective AI and TSA methods for mononuclear aromatic compounds,

0

lbu0

i

0 -

-2

(A])

0

-iJ

-

(TSA)

-4 -6 -B

-10 -121/ -12

-10 I -10

I -8

I -6

i -4

Observed logs

I -2

0

-12 -12

-10

-S

-6

-4

-2

0

Observed logS

Fig. 4a and b. Relationship between log S observed and log S calculated from Eqs. 12 and 13 by respective AI and TSA methods for polynuclear aromatic compounds.

S. Okouchi etal.

260

-1

_ (AI) :

-1

- (TSA)

"~

rJ 3 0

t~

-3

03,

-3

0 -

0

-

-5

-5

-

0

0

c,d

¢.~

oo

0~

-7 0

-7 c~

0

-9 -11 -1

o

o

-9

-7

-9

-9

-7

-5

-3

-11 -1

-1

Observed logs

-5

-3

-1

Observed logS

Fig. 5a and b. Relationship between log S observed and log S calculated from Eqs. 14 and 15 by respective AI and TSA methods for aliphatic c o m p o u n d s .

for the aliphatic compounds (n = 118) log S = -1.243 AI - 0.0001 mp + 0.840 (r = 0.878, s = 0.784)

(8)

log S = -0.029 TSA - 0.009 mp + 1.320 (r -- 0.917, s = 0.630)

(9)

for the mononuclear aromatic compounds (n = 88) log S = -0.918 AI - 0.013 mp + 0.859 (r -- 0.986, s -- 0.355)

(10)

log S = -0.028 T S A - 0.014 mp + 1.393 (r = 0.984, s = 0.384)

(11)

The AI method was well correlated with the water solubilities of the mono- and p o l y n u c l e a r aromatic compounds shown in Eqs. 10 and 12, as well as the TSA method in Eqs. 11 and 13. Their results are shown in Figs. 3 and 4. On the other hand, for the aliphatic c o m p o u n d s , both the AI and the TSA m e t h o d s did not i m p r o v e the c o r r e l a t i o n s as shown in Eqs. 8 and 9, in spite o f the g o o d l i n e a r r e l a t i o n s h i p b e t w e e n T S A and AI in Eq. 5. T h e n , an i n d i c a t o r v a r i a b l e ( H I ) was i n t r o d u c e d , w h i c h was s i m i l a r to the a p p r o a c h o f N i r m a l a k h a n d a n and S p e e c e (1988b), as a new e m p e r i c a l p a r a m e t e r to predict the water solubilities of the aliphatic compounds. log S = - 1.032 A I + 0 . 0 0 4 m p + 1.167 H I - 0.945 (n = 118, r -- 0.974, s = 0.359) (14)

for the p o l y n u c l e a r a r o m a t i c c o m p o u n d s (n = 59) log S = -0.659 AI - 0.009 mp - 0.224 (r - 0.979, s = 0.343)

(12)

log S = -0.023 TSA - 0.011 m p + 0.596 (r = 0.972, s -- 0.397)

(13)

log S -- -0.025 TSA - 0.009 mp + 1.133 HI + 1.235 (n -- 118, r = 0.972, s = 0.369) (15) From Eqs. 14 and 15, a more precise model was obtained by introducing the indicator variable (HI), compared with Eqs. 8 and 9. Figure 5 shows their results. A value of 1 was assigned for 52 alkanes and

Solubility of organic pollutants

alkenes except for the diene compounds, and a value of zero for the 66 remaining compounds. These alkanes and alkenes differed with a constant systematic error from all other compounds used in this work. The anomalous behavior of these compounds has been observed previously by other workers in this area (Nirmalakhandan and Speece 1988b). In conclusion, the adsorbability index gave a good prediction of the water solubilities of 265 hydrophobic organic compounds which were classified into the aliphatic compounds and mono- and polynuclear aromatic compounds, as well as the total molecular surface areas. The adsorbability index can be readily calculated from Table 1 with a hand calculator, whereas the calculation of the total molecular surface areas needs the aid of a computer with the information of interatomic bond lengths, bond angles, van der Waals radii, and torsional angles between Various atoms in a molecule. Therefore, for a simple method to predict the water solubilities of hydrophobic organic compounds, the AI method is suggested.

261

REFERENCES Abe, I., Tatsumoto, H.; Hirashima, T. Prediction of activated carbon adsorption by adsorbability index (AI). Japan J. Water Pollut. Res. 9:153-161; 1986. Kishi, H.; Nakamura, M; Hashimoto, T. Prediction of solubility of aromatic compounds in water by using total molecular surface area. Nippon Kagakukaishi. 1987: 1615-1622. Mackay, D.; Mascarenhas, R.; Shiu, Y. Aqueous solubility of polychlorinated biphenyls. Chemosphere. 9:257-264; 1980. Mackay, D.; Shiu, W.Y. A critical review of Henry's law constants for chemicals of environmental interest. J. Phys. Chem. Ref. Data. 10:1175-1199; 1981. Mallhot, H.; Peters, R.H. Empirical relationships between the l-octanol/water partition coefficient and nine physicochemical properties. Environ. Sci. Technol. 22:1479-1488; 1988. Nirmalakhandan, N.N.; Speece, R.E. Prediction of aqueous solubility of organic chemicals based on molecular structure. Environ. Sci. Technol. 22: 328-338; 1988a. Nirmalakhandan, N.N. Speece, R.E. QSAR model for predicting Henry's constant. Environ. Sci. Technol. 22: 1349-1357; 1988b. Okouchi, S.; Saegusa, H. Prediction of soil sorption coefficients of hydrophobic organic pollutants by adsorbability index. Bull. Chem. Soc. Sapan 62: 922-924; 1989. Pearlman, R.S.; Yalkowsky, S.H.; Banerjee, S. Water solubilities of polynuclear aromatic and heteroaromatic compounds. J. Phys. Chem. Ref. Data. 13:656-562; 1984. Yalkowsky, S.H.; Valvani, S.C. Solubility and partitioning I: Solubility of nonelectrolysis in water. J. Pharm. Sci. 69: 912922; 1980.