Excess Volume and Viscosity of Ethoxy Ethanol with N-Butylamine, Sec

In dian Journ al of Chemi stry Vo l. 43A, September 2004, P ). 1876-1 88 1

Excess volume and vi scosity of ethoxy of amines and alkoxy alcohols make the m intcresting ethanol with n-butylamine, sec-butylamine, fo r our study. A survey of the literature has show n tert-butylamine, n-hexylamine, n-octylamine th at no attempts have been made to study excess volumes and viscosity of binary mi xtures of eth oxy and cyclohexylamine eth anol (EEL) with a seri es of amin es whi ch include Il-butylamine (NBA ), sec-butylamine (SB A) , Me S Subha*, G Na rayana Swa my, M Eswari Bai & terl-butylamine (TBA), n-hexy lam ine (N HA), K S V Kri shn a Rao Il-octylamine (N OA) and cy cl ohexylamin e (CH A) at Department of Chemistry, Sri Kri shn adevaraya Uni versity, 308.15 K aiming for a wider understanding of th e An<1nt apur 5 I 5 003, Ind ia molecular interac ti ons involved. Email : mcssubha@rediffmail .com Recei ved 6 Jal/uC/I }' 2003; revised 28 JUI/ e 2004 Experimental Density measurements were made using bi capill ary Densiti es and viscosities of eth ox y eth anol (E EL) with 1/ ­ pyc nometer hav in g a capillary di ameter of 0.85 mm. butylam ine (N BA), sec-butylamine (SB A), lert-but ylami ne The pycnometer was calibrated using do ubl y di still ed (TBA ), I/ -hexylamin e (N HA), I/ -octylam in e (NOA) and water and th e necessary bu oyancy correc ti ons were cyclohexy lami ne (C HA) have been measured at 308.15 K. From the ex peri me ntal data the excess vo lu me (0'), deviati on in appli ed. The density values were reproducibl e within 3 viscosity ( llE) and the excess molar Gibb's free energy of the ± 0.2 Kgm· . A th ermostaticall y contro ll ed water bath activati on of viscous fl ow (C*E) have been comput ed and capabl e of maintai nin g the temperature constant to l presented as functi on of composition. The parameter d of th e ± 0.02 K was used for th e studies. Grunberg and Nissan has been calcul ated. The observed vari ati ons Vi scosity measurements were made usin g of th e properti es for the above mi xtures conclude th at the in teracti ons betwecn - unlike molecul es predominate over the Ubbelh ocle viscometer. The time of efflu x of a dissociati on effects in th e individual components. It is al so evident constant vo lume of liquid through the capill ary was that th e presence of strong interac ti ons between unli ke molecu les measured with th e help of a pre-calibrated ROCA R is predomin ant and characteri zed by the negati ve vE and positi ve stop watch capabl e of recording ± 0.1 s. The llE, C *E and d l values. The excess volume, deviation in viscosit y and excess molar Gibb's free energy of the ac tivati on of viscous viscometer was ke pt verti cal in a th ermos tat at 308.1 5 fl ow hav e been fitt ed to Red li ch-Ki ster equ ati on to deri ve the K and th e efflu x time for water at 308. 15 K was fo und coe ffi cient s and standard dev iati ons. to be about 302 s. The fl ow time of pure liquids and IPC Code: lilt C17. GOIN 9/04; GOI N 11 /02 li quid mixtures was measured a number of times and the average of the readi ngs was taken. In chemi cal industry there exi sts a continuing need fo r The vi scosity was calculated fro m the average of reli abl e thermodynami c data of binary systems. effl ux time and density p accord ing to: A survey of the literature shows th at very few attempts t·3 have been made to study excess properti es TJ/p = at-bit ... (1) for mixtures containing alkoxy alcohols. Amines and 4 5 alkoxy alcohols . in th eir pure state exhibit self­ where a and b are the characteri sti c constants of the associati on through hydrogen bonding. Amincs are viscometer. These were determined by taking water, better electron donors , which all ow them to have benzene, carbontetrachloride and acetonitrile as specific interac tions. Further, amin es fo rm water calibratin g liquids. The kinetic energy correc ti ons in so luble compounds of medicin al importance. The were calculated from these values and they were molecular interaction study of alkoxy alcohols is of found to be negli gible. The viscosity measurements interest because of investi gating the effect of were accurate to ± 0.5x I 0-4 kg m·t s·t . simultaneous presence of ether and alcoholi c Ethoxy eth anol and all the amines we re purchased function al groups in the same mol ec ule. The presence from Merck KGOA , Germ any. Th e chemi cal s were of etheri al oxygen enhances the ability of the -OH di stilled and kept ti ghtly sealed and protected fro m group of the same molecule to form hydrogen bonds atmos pheric moisture and carbondi oxide as fa r as 6 7 with other organi c mol ecules . . These characteri stics poss ible. Prior to measurements, all liq uid s were kept NOTES ]877

over 0.4 nm molecular sieves to reduce water content In each case, the optimum number of coefficients, Aj , and were partially degassed under vacuum. The was determined from an examination of th e variati on purities of these chemicals were checked by of standard devi at ion, cr( yE) as calculated by measuring their densities and comparin g with those s 9 reported in literature . . Mi xtures were prepared by mixing weighed amounts of the pure liquids adopting ... (8) the method of closed system. The measurements were made with proper care in an AC room to avoid where m is the number of ex perimental data and II is evaporati on losses. the number of coeffici ents in Eq. 8. Aj coefficients considered (n = 5 in the present case), have been Results and discussion presented in Table 2. The excess functions 1{ and 0, Grunberg and From Table ], it is observed that the vi scosity of lo Nissan interaction parameter i and the Gibb's free binary liquid mixtures under study varied non-linearly energy of activ ati on of viscous flow C*E were with the mol e fraction of EEL (XEEL) . This suggests calculated respecti vely from Eqs 2 to 5. the presence of intermolecul ar interacti ons between unlike mol ec ul es of these mixtures. A simil ar s 11 E = 11 - [x 11 1 + (I-x) 11 2] ... (2) observation was made by Narayana Swamy et al. from the viscosity studies of binary liquid mixtures of 0 = V - [XVI + ( l-x)V ] . . . (3) 2 acetonitrile + amines. From Fig. ], it is observed that is negati ve over In 11= x ln 111 + (1-x) In 11 2 + x(1-x)i ... (4) 0 the whole range of composi tion and increases in the order of increase with size of the normal amine molecule. But in the case of EEL + NBA, + SBA and The molar vo lume V of a mi xture is calculated usi ng + TBA positi ve 0 va lues are observed only at hi gher Eq.6. mole fractions of EEL. An interpretati on to th is behaviour can be given using the experience made V=M/p .. . (6) with the quantitative evalu ation of alcohol + amin e mixtures by the ERAS model proposed by the earl ier where M = xM I + (I-X)M2' X is a mole fraction of workers 12- 16. The observed negative excess vo lu mes component 1, MI and M2 are molecul ar weights of may be explained in terms of two opposing effects. compounds I and 2 respectively. Mixing of EEL with different amines will induce the The measured density (p) and viscosity (11) at mutual dissociati on of component mol ecul es and the 308.15 K for the mixtures of 2-ethoxyethanol (EEL) + fo rmation of hydrogen bonds between unli ke II-butylamine (NBA), + sec-butylamine (SBA), + terl­ molecules. The former effect leads to positive excess butylamine (TBA), + II-h exylamine (NHA), + /l­ volume and the latter effect leads to negative excess octy lamine (NOA) and + cyclohexylamine (CHA) are vo lume. The actual volume change wou ld depend used to calculate the excess molar volume (0), upon the rel ative strength s of the two effects. The E dev iati on in viscosity ( 11 ), excess Gibb's free energy observed negative va lues of 0 show th at the main of activati on of viscous fl ow (C*E) and Grunberg­ contribution to 0 is due to hydrogen bond formati on l Nissan interaction parameter (d ) and the results are (OH ...... N) between unlike molecules. Moreover, the presented in Table I. negative values of VI:: may also be partly due to the The va ri ation of the parameters 0 and 11 E with the specific acid-base interactions between EEL and mole fraction of EEL (XEEL) for the systems under amine molecules by considering EEL as Lew is acid study are graphically shown in Fi gs 1 and 2 and amines as Lewis bases. Very recently Nam­ respectively. Tram l7 emphasized the importance of acid-base The mixing quantities, yE (0, 11 E and C*E) were interactions between tert-butyl alcohol and N,N­ fitted to Redlich and Ki sterll type equation by least­ dimethylformamide/N ,N-dimethyl acetamide in order square fitting. to evalu ate the interac ti on energy of alcohol-amine systems. 5 J yE = x( l-x) LA . (1- 2x)j-1 ... (7) From the examination of the results in Tabl e and .1 = 1 J Fig. J, it is observed that the negative values of 0 fa ll 1878 INDIAN J CHEM, SEC A, SEPTEMBER 2004

Table I-Values of density (p), viscosity (11), deviation in viscosity ( llE), excess molar vo lume (\/'\ excess Gibbs free energy of activation of viscous now (C' E) and Grunberg-Ni ssa n interaction parameter (d') for the binary mi xtures of 2-ethoxyethanol (EEL) + am i nes at 308. 15 K

Mole fraction pxl0') 11 x I 03 1{x103 V'x 106 C*Ex103 (/' 3 of EEL, XEEL Kg m') Kg m" s-' Kg m" s" m mo l" N mar'

2-Ethoxyethanol + II-butylamine 0.0000 0.7239 0.4249 0.0000 0.0000 0.00 0.0802 0.7445 0.5335 0.0261 -0.7426 74.48 1.7487 0.2044 0.7654 0.6473 0.0122 -0.373 1 101.62 1.0430 0.3059 0.7857 0.7671 0.0276 -0.4824 128.51 1.0 I 07 0.4065 0.8055 0.8896 0.0466 -0.5316 143.17 0.9908 0.5068 0.8248 1.0066 0.0605 -0.5120 143.41 0.9572 0.6065 0.8426 1.l148 0.066 1 -0.3183 132.04 0.9 165 0.7058 0.8599 1.2089 0.0581 -0.0726 108.38 0.8555 0.8434 0.8779 1.2947 0.0024 0.9432 52.99 0.5828 0.9024 0.8978 1.3757 0.0227 0.0155 39.98 0.7391 1.0000 0.9173 1.4534 0.0000 0.0000 0.00 2-Ethoxyethanol + sec-butylamine 0.0000 0.7083 0.3996 0.0000 0.0000 0.00 0.1045 0.7325 0.5211 0.0114 -0.4649 77.25 1. 3953 0.2080 0.7553 0.64 19 0.0231 -0.706 1 12 1.68 1.2471 0.3105 0.7778 0.7668 0.0400 -0.8908 148.41 1.1719 0.4120 0.7985 0.8957 0.0619 -0.8367 163.63 1.1361 0.5124 0.8184 1.0158 0.0762 -0.6902 162. 17 1. 0863 0.6 188 0.8394 1.1303 0.0786 -0.5059 144.55 1. 0209 0.7103 0.8567 1.2171 0.0690 -0.2457 119.07 0,9557 0.8078 0.8762 1.3045 0.0536 -0.0805 85.42 0.9024 0.9043 0.8954 1.3845 0.0319 0.1080 46.67 0.8668 1.0000 0.9173 1.4534 0.0000 0,0000 0.00 2-Ethoxyethanol + tert-butylamine 0.0000 0.6812 0.4126 0.0000 0.0000 0.00 0.1082 0,7121 0,5474 0.0222 -1.0918 83 ,61 1.5181 0.2 145 0,7389 0,6798 0,0439 -1.4979 132.03 1,3607 0.3189 0,7644 0.8102 0.0657 -1.6928 157.87 1.2583 0.4214 0.7897 0.9309 0.0797 -1.8460 162.93 1. 1611 0.5221 0,8 136 1.0461 0,0901 - 1. 8 124 156.85 1.0940 0.6211 0,8361 1.1494 0.0904 -1.6109 139.28 1.0304 0.7182 0,8547 1.245 1 0.0850 -0.9740 117.13 0.9891 0.8138 0.8732 1.327 1 0.0675 -0.3580 86.09 0.9475 0.9077 0,8934 1.3994 0.0421 0.03 18 48.40 0.9355 1.0000 0,9173 1.4534 0.0000 0.0000 0.00 2-Ethoxyeth anol + II-hexylamine 0,0000 0.7522 0.6 0.0000 0.0000 0.00 0.1321 0.7732 0.7283 0.0156 -0.7523 46.75 0.6710 0.2550 0.7921 0.8766 0,0590 -1.0886 94.12 0,8082 0.3698 0.8099 1.0256 0.1100 -1.2221 128.59 0.8967 0.4772 0.8274 1.1724 0.1652 -1.2981 152.36 0.9930 0.5779 0.8432 1.3048 0,2116 -1.1387 163.96 1.0890 0,6726 0.8589 1.4256 0.2516 -0.9785 167.00 1.2279 0.7616 0.8736 1.4689 0.2 190 -0.7139 137.36 1.2203 0.8456 0.8886 1.4569 0, 1353 -0.5051 86.39 1.0649 0.9249 0.9038 1.4449 0,0556 -0.3373 37.35 0. 8723 1.0000 0.9173 1.4534 0.0000 0.0000 0.00

2-Ethoxyethanol + II-octylam in e 0.0000 0.7702 0.9267 0.0000 0.0000 0.00 0.1595 0.7898 1.1 361 0,1254 -0.9703 87.4 1 0.9844 0.2992 0.7989 1,2384 0.1541 -0.1319 112.66 0.7408 COlltd.- NOTES 1879

Table I-Values of density (p), viscosity (11), deviation in viscos ity (l1E), excess molar vo lume (vE), excess Gibbs free energy of ac ti va ti on of viscoll s flow (C'E) and Grunberg-Nissan interacti on parameter (dl) for th e binary mi xtures of 2-eth oxyethanol (EEL) + amines at 308. 15 K-Colltd

3 3 3 6 E 3 Mole fraction px 10· 11 x I 0 11 EX 10 vEx I 0 C' x 10 3 1 1 3 l l of EEL , XEEL Kg m· Kg m· S· I Kg m· S· I m mor N mor

0.4226 0.8254 1.51 24 0.363 1 -1.8569 195.85 1.2282 0.5324 0.8421 1.6548 0.4477 -2.0284 220.63 1.3668 0.6307 0.8579 1.7500 0.4911 -2.0446 226.52 1.5111 0.7193 0.8726 1.7254 0.4198 -1.9074 191.43 1.4756 0.7994 0.8862 1.6542 0.3065 -1.6499 141.04 1.3702 0.8723 0.8975 1.5684 0. 1823 -1.1487 86.38 1.1997 0.9389 0.9083 1.4968 0.0756 -0.6448 36.90 0.9924 1.0000 0.9173 1.4534 0.0000 0.0000 0.00 2-Ethoxyethanol + cyclohexylamin e 0.0000 0.8527 1.3249 0.0000 0.0000 0.00 0.1163 0.863 1.3451 0.0053 -0.132 1 0.80 0.0425 0.2284 0.8713 1.3662 0.0120 -0.3272 3.34 0.0542 0.3366 0.8779 1.3912 0.0230 -0.4575 8.66 0.0792 0.4411 0.8842 1.41 85 0.0369 -0.4810 15.00 0.1113 0.542 1 0.8856 1.4366 0.0420 -0.401 3 20.0 1 1.0744 0.6398 0.8957 1.4572 0.0501 -0.2024 21.16 0.1560 0.7342 0.9008 1.4594 0.0402 -0.0511 17.38 0.1472 0.8257 0.9056 1.455 1 0.024 1 -0.0115 11.08 0.1203 0.9142 0.911 1.4501 0.0077 -0.0 175 4.08 0.0723 1.0000 0.9173 1.4534 0.0000 0.0000 0.00

Table 2-Coefficients AJ of Eq. (7) and standard deviations a( yE) of binary mi xtures of 2-ethoxyethanol + amines at 308.15 K

yE AI A2 A3 A4 A, a(yE)

2-Ethoxycth anol + Il -butylamine vEx I06(m 3 mor l) -2.210 0.485 10.359 7.214 -20.782 0.511 ll ExlO\Kg m· 1 S· I) 0.280 0.178 -1.055 -0.355 1.536 0.081 C'Ex IO'{N morl) 595.316 -37.670 -508.932 -403.974 1002.489 26.972

2-Ethoxyeth anol + sec-butylamine vEx l06(m'mOr l) -2.899 3.027 0.715 1.147 1.304 0.206 11 EX IO\Kg n,- I S-I) 0.299 0.205 -0.279 -0.083 0.305 0.004 c*Ex I03(N mor l) 65 1. 817 -1 3 1.994 - 102.927 -78.443 242.451 2.669

2-Ethoxyethanol + tert-butylamine vEx lO6(m 3 mor l) -7.480 2.005 6.433 8.465 -5 .830 0.22 1 11 EX IO\Kg m· 1 S· I) 0.354 0.139 -0.036 0.045 0.075 0.005 C'Ex l0\ N morl) 635.858 -1 96.8 13 121.104 18.619 26.747 3.866

2-Ethoxyethanol + Il-hexylamine vEx I 06( m3 mor I) -5.087 1.684 2.6 11 -0.029 -5.770 0.151 11Ex lO\Kg m·1 S·I) 0.725 1.11 9 0.300 -0.945 -1 .026 0.046 C'Ex IO\N morl) 632.077 343.734 59.898 -329.378 -454.088 18.855

2-Ethoxyethanol + II-octylamine vEx IO\ m3 mor l) -7 .628 -1 3.652 14.882 25.265 -34.761 1.655 l{ x lO'{Kg m·1 S·I) 1.737 2.175 -2. 146 -3.386 2.749 0.0827 C'Ex lO\ N mol·l) 868.494 692.324 -773.922 - 1228.673 1017.518 36.326

2-Ethoxyeth anol + cyclohexylamine vEx IO\m'morl) -1.748 2.310 3.334 -2.587 -2.602 0.071 11 EX I O,{Kg m· 1 S· I) 0.168 0.187 -0. 106 -0.233 -0.044 0.009 C' Ex 103(N mor I) 73.332 90.1 82 -77.970 -93.337 22.004 1.012 1880 INDI AN J C HEM. SEC A, SEPTEMBER 2004

0.5 in the sequ ence: EEL + CHA < + NB A < + SB A < + NHA < + TB A < + NOA. From Fi g. I , it is observed that the negati ve excess 0.0 vo lumes of normal amines with EEL increase with increase in chain length of amines. This can be ex pl ain ed by considerin g amines as proton acceptors r--. -0.5 and EEL as proton donor. As th e chain length of th e (3 normal amin es increases, proton- acceptin g ab ility of E M th ese amines increases and electron density wi ll be E '-' -1.0 more and more on nit rogen atom of NH2 group due to 'D 3 inductiv e effect. So, as the chain length of the amines >< til increases, th e interacti on ab ili ty (hydrogen bond ing > -1.5 abili ty) of amines with EEL in creases. In th e case of branched amin es, negative yE va lu es in creases with increase in branching. Th is is very -2.0 cl ear th at as the amin es become more and more branched, the proton accepting ability in creases due to the in crease in -CH.1 groups on th e ca rbon atom -2.5 attached to amin e group. However, sl ight pos iti ve \I" val ues are observed at hi gher EEL mole fr actio n in case of NBA, SBA and TBA indicati ng lesser speci fi c interacti ons at these mole frac ti ons. A similar 18 Fig. I- Plots of excess volume (V' ) vs mole fracti on of 2- observation was made by Haraschta el al. from the ethoxyeth ano l CrEEL) at 308.15 K for the binary mix tures of EEL + + l ert - with NBA (_), SBA (D), TBA ( .A ), NHA (- ), NOA (0) and C HA yE studies of y-picolin e sec-butano l and (t-) butanol. In the case of cyclohexylamine, '0' valu es are less negati ve th an th e corresponding norm al hexy lamine, 0.60 whi ch may be due to steri c and other effects because of cyclic nature of cyclohexylamin e. 0.50 Figure 2 shows th at 11E va lues are pos iti ve over the ,-., who le compositi on range fo r all the systems under en study. A correlati on between the si", ns of ll E and ,;E -: E 0.40 has been observed for a number of bin ary systems, t9.2U bO ~ ll E bein g pos iti ve, where yE is negati ve and vice­ M versa. In general , for systems where di spersion and 3 0.30 til dipolar interac ti ons are operatin g ll E valu es are fo un d ~ to be negati ve whereas charge transfer and hydrogen 0.20 bonding interactions lead to the formation of compl ex species between unlike molecul es th ereby resulting in positive ll E values9. The positi ve valu es of ll E fo r th e 0.10 mixtures of EEL + amines fall in the order: EEL + CHA < + NBA < + SBA < + TB A < + NHA < + NOA. 0.00 It can be predi cted that in View of the strong proton 0.0 0.2 0.4 0.6 0.8 1.0 donating ability of EEL and stron g; proton accepting ability of amines, th e overall negati ve yE va lues and overall positi ve l1 E values in all th ese systems may be regard ed as an evid ence for the formati on of 2 sets of Fig. 2-Plots of deviati on in viscosity l1 E vs mo le fracti on of 2- hydrogen bonds between EEL and ami nes . Among ethoxyethanol (XEEtJ at 308. 15 K for th e bin ary mi xtures of EEL with NBA (_), SBA (D), T BA ( .A ), NHA (_), NOA (0) and CHA them, the first set of hydrogen bond formati on is (M between N atom of amino group of am in e and H atom NOT ES 188 1 of - OH group of ethoxy ethanol and the second set of presence of strong interacti ons between unli ke hydrogen bond mo lecules is predominant and characteri zed by th e negative 0 and positive llE, C*E and d l values. H I R- ~------H- O - C2 H 5 -0- C 2 H 5 References H Ramana Reddy K Y, Rambabu K, Devarajulu T & Kri shnaiah A, Phys Chelll Liq. 28 (1994) 16 1. 2 Pal A & Sin gh W, J Chelll Th erlllodYllalll ics. 29 ( 1997) 639. fo rmati on is between H atom of amino group of 3 Pal A, Ill diall J Chelll , 37A (1 998) 109. amines and oxygen atom of etheri c group of EEL. 4 Rowlinson J S, Liqllid all d Liqllid Mixtll res, 2nd edition Among th e two, the first set of hydrogen bond (B utterworths: London), (1969) 159. fo rmati on predominates. 5 Pri gogin e I, Defay R & Everett B H, Chelllical TherlllodYll alllics Trall s/ator (Lo ngman Green & Co, London), (1953) 470. H------O-C H - I I 2) 6 Ful vio C, Marcheselli L, Tassi L & Tosi G, Call J Chelll. 70 R-N C H --OH ( 1992) 2895. I 2 ) 7 Pal A, Sharma H K & Sin gh W, Ill diall J Chelll. 34A ( 1995) H 987. 8 Narayana Swamy G, Subha M C S & Srini vasa Rao P. From Table 1, it is also observed that all th e values of AClistica, 75 ( 199 1) 86. 9 Ramana Reddy K N, Reddy K S & Krishnaiah A, J Chelll C*E are found to be positi ve whi ch is an indicati on of £ lI gg Data, 39 ( 1994) 6 15. 9 th e presence of strong specific interacti ons and fall in 10 Grun berg L & Nissan A H, Natllre (Londo n), 164 (19-19) the order: EEL + C HA < + NBA < + SBA < + TBA < 799. + NHA < + NOA. II Redli ch 0 & Ki ster A T , J Ill d £lIgg Gelll , 40 (1948) 345. 1 1 11 1} 12 Bender M, Hauser J & Heintz A, Ber Bllllsel/ -Ges Pin's ort an oore- and Ramamoorthy--'- reported F d M G elll. 95 ( 199 1) 80 1. th at for any binary liquid mi xture, the positi ve value 13 Funke H, Wetzel M & Hei ntz A, J Pll re Appl Chelll, 6 1 of i indicates th e presence of strong· interacti ons and (1989) 1429. th e negati ve valu e of d l indicates the presence of 14 Hei nt z A, Naicker P K, Yerevkin S P & Pfestorf. Ber weak interacti ons between th e components. On thi s BII I/ Sell-Ges Phys Chelll , 102 ( 1998) 953. l IS Mohren S & Heintz A, Flu id Phase £qlli/ib. 133 (1997) 247. bas is, th e d values in the present study for all the 16 Reimann R & I-le intz A, J SO /Il tioll Chelll , 20 ( 199 1) 29. systems confirm th e presence of strong interacti ons 17 Nam-T ram H, J Phys G elll , 98 (1994) 5362. between the component molecul es. A similar 18 Harascht a P, Heintz A, Lehmann J K & Peters A, J Ch elll l £ lI gg Data, observati on was made by Subha et 0 1. 24 fro m th e d 44 ( 1999) 932. 19 Marcus Y, lOll So/vatioll (Wil ey Interscience, New York). valu es of the binary liquid mi xtures of propio ni c acid ( 1985). with alcohols. 20 Prolongo M G, Masegosa R M, Fuentes H I & Horta A. J In conclusion, it may be said that the observed Phys Chelll. 85 ( 1984) 2 163. variation of the properti es of th e mi xtures studi ed 21 Fort R J & Moore W R, TrailS Faraday Soc. 62 (1966) 11 12. supports th e view that the interacti ons between unli ke 22 Ramamoorthy K, J Pllre Appl Phys. II ( 1973) 554. 23 Ra mamoorthy K, J Pllre App/ Phys. II ( 1973) 556. molecul es predominate over the di ssociation effects in 24 Subha M C S, Rao K C, Swamy G N & Rao S B, J Ph),s the individual components. It is also evident that th e Gelll Liq, 18 ( 1988) 185.