www.scielo.br/eq Volume 35, número 2, 2010 23Ecl. Quím., São Paulo, 35 - 2: 23 - 32, 2010 Artigo/Article ViSCometriC inVeStigationS and moleCular interaCtionS of Some deriVatiVeS of 5-SubStituted indole diHydropyrimidineS in mixed organiC SolVentS L. C. Heda, Rashmi Sharma, S. R. Mosalpuri and Pramod B. Chaudhari* Research Laboratory, Dept. of Chemistry, S.D. Govt. College, Beawar, 305901, Rajasthan, (India). *Corresponding author, Tel.: +919052168560 E-mail: prmdchaudhari@yahoo.co.in abstract: Colloid chemical behavior of indole dihydropyrimidines in non-aqueous solvent mix- ture benzene-methanol of varying composition has been investigated by viscometric measure- ments at 303K± 0.1. The viscosity of the system increases with the increase in concentration. The Trend Change Point (TCP) values have been determined by intersection of two straight lines, which are found to be dependent on the composition of solvent mixtures. The study confirms that the nature of synthesized compounds agglomerate formed below and above 50% benzene concentration is quite different. The viscometric data have been analyzed in terms of Einstein, Vand, Moulik and Jones-Dole equations. These well known equations have been successfully applied to explain the results of viscosity measurements and the viscometric pa- rameters show that the behavior of compound changes in the proximity of 50% benzene con- centration. Keywords: Substituted indoles, Dihydropyrimidines, Trend change point, viscosity, and Solute-Solvent in- teraction. introduCtion In the family of heterocyclic compounds Nitrogen containing heterocycles are an important class of compounds in the medicinal chemistry and also contributed to the society from biological and industrial point which helps to understand life processes.1 This seems to be because pyrimidines represents one of the most active class of compoun- ds possessing wide spectrum of biological activity viz. significant in vitro activity against unrelated DNA and RNA, viruses including polio herpes viruses, diuretic, antitumor, anti HIV, cardiovas- cular.2 Biginelli compounds show a diverse range of biological activities. The interest focused on Biginelli compounds leading to the development of Nitractin, 3 that has excellent activity against the virus of trachoma group, the same compounds also exhibit antibacterial activity. 4-Aryl dihydro- pyrimidines e.g. Nifedipine are the important and most studied class as Calcium channel modulars, in 1975 their introduction in clinical medicine for the treatment of cardiovascular diseases.4 some of the analogues were screened as antitumor agents. Pyrimidine –5-carboxamide of type was reported to possess anticarcinogenic activity, anti- inflammatory, 5 analgesic.6 The topsentins, as an- tiviral and antitumor agents from marine sponge represents the emerging class of bis indole alka- loids. During the search of bioactive natural pro- Ecl. Quím., São Paulo, 35 - 2: 23 - 32, 201024 Artigo Article ducts act as cytotoxic and antifungal compounds belongs to class noprtopsentins.7 The presence of highly substituted indole and indolines in a va- riety of bioactive molecular targets has inspired a number of groups including ours to develop new and improved routes to their synthesis.8 Recently there is a much interest in the synthesis of small molecules for chemist in accelerating drug disco- very.9 In the view of the potential applications of these compounds, present work has been un- dertaken to explain colloid chemical behavior in mixed solvents. Benzene and methanol has been chosen as the co solvents in the title study. The mixed solvents have a tendency to interact with compounds, which affect the aggregation of molecules. The viscosity data based on various equations has been extensively used to furnish information concerning the structural changes in solution trend change point (TCP) and nature of molecule-solvent interaction. This vital informa- tion plays an important role in their selection for various industrial and biological applications. experimental The most obvious approach for carrying out the synthesis of substituted indole dihydropyrimi- dines is due to potent biological activity of indo- les as well as dihydropyrimidines. The synthesis begins from the commercially available indole; we were able to synthesize 5-substituted indoles in three steps using known protocol.10 The fur- ther formylation with DMF/POCl3 by Wismeyer – Hack method to obtain Indole 3-carboxaldehyde in good yields.11 In cyclocondensation reaction of indole carboxaldehyde, thiourea and ethylacetoacetate in the presence of acid catalyst by refluxing in etha- nol to afford indole dihydropyrimidines (1).12 N H NH NH C2H5OOC S R Compound R A H B Br C Cl D I 1 Correlating 1H NMR and IR data with data for corresponding compounds made the structu- ral assignments for indole 3-carboxaldehydes and indole dihydropyrimidines. Solubility of com- pounds in benzene and methanol was determined by preparing solutions of compounds in solvents. The viscosity of the solutions was measured by Ostwald′s viscometer in thermostat bath. The vis- cometer was calibrated frequently with distilled water. reSultS and diSCuSSion The flow of characterization of solutions in terms of viscometric measurements has been em- ployed as a tool to find out the TCP of molecule in benzene - methanol mixtures. The viscosity of solutions of varying composition of benzene- me- thanol mixtures increases with the increase in the concentration. Ecl. Quím., São Paulo, 35 - 2: 23 - 32, 2010 25 Artigo Article table – 1.Viscosity, η, of compound A in benzene-methanol at 303K ± 0.1 in poise Volume % of methanol Conc 40% 60% 80% 100% 0.0002 0.589 0.566 0.549 0.529 0.0004 0.604 0.581 0.561 0.541 0.0006 0.616 0.593 0.570 0.551 0.0008 0.620 0.599 0.574 0.553 0.0010 0.627 0.604 0.580 0.557 0.0012 0.634 0.612 0.585 0.561 0.0014 0.643 0.619 0.589 0.564 table – 2. Viscosity, η, of compound B in benzene- methanol at 303K ± 0.1 in poise Volume % of methanol Conc 40% 60% 80% 100% 0.0002 0.592 0.568 0.549 0.529 0.0004 0.607 0.585 0.565 0.542 0.0006 0.619 0.596 0.575 0.551 0.0008 0.624 0.601 0.577 0.555 0.0010 0.630 0.607 0.582 0.559 0.0012 0.638 0.616 0.588 0.564 0.0014 0.647 0.624 0.593 0.567 table – 3. Viscosity, η, of compound C in benzene- methanol at 303K ± 0.1 in poise Volume % of methanol Conc 40% 60% 80% 100% 0.0002 0.591 0.571 0.551 0.533 0.0004 0.614 0.593 0.569 0.546 0.0006 0.627 0.606 0.581 0.559 0.0008 0.632 0.610 0.586 0.565 0.0010 0.639 0.616 0.593 0.570 0.0012 0.646 0.620 0.596 0.573 0.0014 0.651 0.629 0.600 0.576 table – 4. Viscosity, η, of compound D in benzene-methanol at 303K ± 0.1 in poise Volume % of methanol Conc 40% 60% 80% 100% 0.0002 0.596 0.573 0.553 0.535 0.0004 0.621 0.595 0.573 0.551 0.0006 0.635 0.609 0.587 0.564 0.0008 0.641 0.615 0.592 0.568 0.0010 0.647 0.621 0.596 0.571 0.0012 0.652 0.627 0.599 0.573 0.0014 0.658 0.634 0.602 0.578 Ecl. Quím., São Paulo, 35 - 2: 23 - 32, 201026 Artigo Article The increase in viscosity with the increa- se in concentration may be due to the increasing tendency of molecules to associate in the form of clustering entity in the solvent system. The numbers of workers have reported the molecular interaction and characterizing aspects of physico- chemical behavior of binary liquid mixtures and mixed solvent.13 The difference in the viscosities of solutions in varying composition of benzene- methanol mixtures is mainly due to the differen- ce in the viscosities of the solvent mixtures. The plots of viscosity (η) against concentration (C) are characterized by an intersection of two straight li- nes at a definite concentration corresponding to TCP of the molecule (Fig.1-4). FIG 1 0.50 0.52 0.54 0.56 0.58 0.60 0.62 0.64 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) η 40 60 80 100 FIG 2 0.50 0.52 0.54 0.56 0.58 0.60 0.62 0.64 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) η 40 60 80 100 FIG 3 0.50 0.52 0.54 0.56 0.58 0.60 0.62 0.64 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) η 40 60 80 100 FIG 4 0.50 0.52 0.54 0.56 0.58 0.60 0.62 0.64 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) η 40 60 80 100 FIG-5 1.5 1.6 1.7 1.8 1.9 2.0 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) Φ 40 60 80 100 FIG-6 1.5 1.6 1.7 1.8 1.9 2.0 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) Φ 40 60 80 100 FIG 1 0.50 0.52 0.54 0.56 0.58 0.60 0.62 0.64 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) η 40 60 80 100 FIG 2 0.50 0.52 0.54 0.56 0.58 0.60 0.62 0.64 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) η 40 60 80 100 FIG 3 0.50 0.52 0.54 0.56 0.58 0.60 0.62 0.64 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) η 40 60 80 100 FIG 4 0.50 0.52 0.54 0.56 0.58 0.60 0.62 0.64 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) η 40 60 80 100 FIG-5 1.5 1.6 1.7 1.8 1.9 2.0 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) Φ 40 60 80 100 FIG-6 1.5 1.6 1.7 1.8 1.9 2.0 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) Φ 40 60 80 100 FIG 1 0.50 0.52 0.54 0.56 0.58 0.60 0.62 0.64 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) η 40 60 80 100 FIG 2 0.50 0.52 0.54 0.56 0.58 0.60 0.62 0.64 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) η 40 60 80 100 FIG 3 0.50 0.52 0.54 0.56 0.58 0.60 0.62 0.64 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) η 40 60 80 100 FIG 4 0.50 0.52 0.54 0.56 0.58 0.60 0.62 0.64 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) η 40 60 80 100 FIG-5 1.5 1.6 1.7 1.8 1.9 2.0 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) Φ 40 60 80 100 FIG-6 1.5 1.6 1.7 1.8 1.9 2.0 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) Φ 40 60 80 100 FIG 1 0.50 0.52 0.54 0.56 0.58 0.60 0.62 0.64 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) η 40 60 80 100 FIG 2 0.50 0.52 0.54 0.56 0.58 0.60 0.62 0.64 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) η 40 60 80 100 FIG 3 0.50 0.52 0.54 0.56 0.58 0.60 0.62 0.64 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) η 40 60 80 100 FIG 4 0.50 0.52 0.54 0.56 0.58 0.60 0.62 0.64 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) η 40 60 80 100 FIG-5 1.5 1.6 1.7 1.8 1.9 2.0 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) Φ 40 60 80 100 FIG-6 1.5 1.6 1.7 1.8 1.9 2.0 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) Φ 40 60 80 100 fig. 1-4 Plot of η versus C for compound A-D in benzene-methanol. Of course this is the maximum concentra- tion of molecular dispersion where balancing of the internal forces causes the formation of aggre- gates. It is apparent from the data that the values of TCP are dependent on the composition of sol- vent mixtures. The values of TCP in the solution containing benzene below 50% are lower as com- pared to those containing higher volume percent of benzene. This may be attributed to the change in the mobility of the molecules due to change in the dielectric constant of the solvent mixture ha- ving different composition of benzene-methanol. Further it is suggested that predominance of li- pophilic character in the solvent mixture plays a pertinent role in the clustering alignment of the solute molecules. Thus there is delay in the ag- gregation due to increase in the interaction be- tween lipophilic solvent and solute molecules. The viscosity of solutions as well as those of the solvent mixtures increases as the volume percent Ecl. Quím., São Paulo, 35 - 2: 23 - 32, 2010 27 Artigo Article of benzene increases which may be attributed to the cumulative effect of the variation of dielectric constant, degree of aggregation and the nature of the agglomerate. The values of specific viscosity (ηsp) of so- lutions in varying compositions of benzene-me- thanol mixtures also increase with the increase in the concentration. FIG 1 0.50 0.52 0.54 0.56 0.58 0.60 0.62 0.64 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) η 40 60 80 100 FIG 2 0.50 0.52 0.54 0.56 0.58 0.60 0.62 0.64 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) η 40 60 80 100 FIG 3 0.50 0.52 0.54 0.56 0.58 0.60 0.62 0.64 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) η 40 60 80 100 FIG 4 0.50 0.52 0.54 0.56 0.58 0.60 0.62 0.64 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) η 40 60 80 100 FIG-5 1.5 1.6 1.7 1.8 1.9 2.0 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) Φ 40 60 80 100 FIG-6 1.5 1.6 1.7 1.8 1.9 2.0 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) Φ 40 60 80 100 FIG 1 0.50 0.52 0.54 0.56 0.58 0.60 0.62 0.64 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) η 40 60 80 100 FIG 2 0.50 0.52 0.54 0.56 0.58 0.60 0.62 0.64 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) η 40 60 80 100 FIG 3 0.50 0.52 0.54 0.56 0.58 0.60 0.62 0.64 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) η 40 60 80 100 FIG 4 0.50 0.52 0.54 0.56 0.58 0.60 0.62 0.64 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) η 40 60 80 100 FIG-5 1.5 1.6 1.7 1.8 1.9 2.0 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) Φ 40 60 80 100 FIG-6 1.5 1.6 1.7 1.8 1.9 2.0 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) Φ 40 60 80 100 FIG-7 1.5 1.6 1.7 1.8 1.9 2.0 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) Φ 40 60 80 100 FIG-8 1.5 1.6 1.7 1.8 1.9 2.0 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) Φ 40 60 80 100 FIG -9 0.00 0.05 0.10 0.15 0.0000 0.0004 0.0008 0.0012 0.0016 C(mol/l) η s p 40 60 80 100 FIG -10 0.00 0.05 0.10 0.15 0.0000 0.0004 0.0008 0.0012 0.0016 C(mol/l) η s p 40 60 80 100 FIG -11 0.00 0.05 0.10 0.15 0.0000 0.0004 0.0008 0.0012 0.0016 C(mol/l) η s p 40 60 80 100 FIG -12 0.00 0.05 0.10 0.15 0.0000 0.0004 0.0008 0.0012 0.0016 C(mol/l) η s p 40 60 80 100 FIG-7 1.5 1.6 1.7 1.8 1.9 2.0 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) Φ 40 60 80 100 FIG-8 1.5 1.6 1.7 1.8 1.9 2.0 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) Φ 40 60 80 100 FIG -9 0.00 0.05 0.10 0.15 0.0000 0.0004 0.0008 0.0012 0.0016 C(mol/l) η s p 40 60 80 100 FIG -10 0.00 0.05 0.10 0.15 0.0000 0.0004 0.0008 0.0012 0.0016 C(mol/l) η s p 40 60 80 100 FIG -11 0.00 0.05 0.10 0.15 0.0000 0.0004 0.0008 0.0012 0.0016 C(mol/l) η s p 40 60 80 100 FIG -12 0.00 0.05 0.10 0.15 0.0000 0.0004 0.0008 0.0012 0.0016 C(mol/l) η s p 40 60 80 100 fig. 5-8 Plots of φ versus C for vompound A-D in benzene-methanol. The nature of curves and TCP values are in good agreement with those observed for vis- cosity data. The fluidity of solutions in benzene- methanol mixtures decreases with the increase in the concentration as well as with the increase in volume percent of benzene (Fig. 3). A perusal of Table-2 indicates that TCP values are in good agreement with those derived from viscosity and specific viscosity curves and are dependent on the solvent composition. The viscosity results have been explained in terms of equations proposed by Einstein14 and Vand. 15 einstein: ηsp = 2.5 V C Vand: 1/C = (0.921/V) x [1/log (η/η0)] + QV Where V, C, Q, η, η0 and ηsp are molar volu- me, concentration, interaction coefficient, viscosi- ty of the solution, viscosity of solvent and specific viscosity respectively. The plots of specific vis- cosity (ηsp) against concentration (C) are charac- terized by an intersection of two straight lines at a definite concentration, which corresponds to the TCP. The plots with intercept almost equal to zero are linear below TCP, which shows that the equa- tion proposed by Einstein are applicable to dilute solutions. 16 It is observed that the values of mo- lar volume V obtained from the plots of Einstein equation and Vand equation. Ecl. Quím., São Paulo, 35 - 2: 23 - 32, 201028 Artigo Article table – 5. Values of molar volume (V) in benzene – methanol derived from Einstein and Vand equations compound %of methanol Einstein equation Vand equation V1 V2 V1 V2 compound A 40% 47.6600 27.7372 80.3960 53.9520 60% 48.2680 24.8596 68.5360 59.0760 80% 38.7288 19.1484 74.9440 51.6160 100% 42.0640 14.0272 55.5680 48.3600 compound B 40% 46.7800 26.7800 93.2760 59.1720 60% 51.7280 28.4644 75.4320 56.8120 80% 48.3360 19.5212 72.6560 55.5640 100% 42.8600 15.5160 56.5880 50.6400 compound C 40% 63.7520 22.6224 92.9160 77.2280 60% 63.7520 22.6224 84.0840 75.8240 80% 56.4240 16.6068 80.4800 71.1320 100% 51.2000 14.3560 71.6560 66.2600 compound D 40% 68.5840 19.0068 106.9400 88.4320 60% 65.9360 23.5528 96.2720 82.1600 80% 63.5680 11.9428 86.6320 81.6600 100% 55.4640 12.4064 83.2640 71.3760 It is interesting to note that the values of molar volume enumerated from these equations are almost equal and the trend remains unaltered irrespective of the type of equation applied. FIG-7 1.5 1.6 1.7 1.8 1.9 2.0 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) Φ 40 60 80 100 FIG-8 1.5 1.6 1.7 1.8 1.9 2.0 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) Φ 40 60 80 100 FIG -9 0.00 0.05 0.10 0.15 0.0000 0.0004 0.0008 0.0012 0.0016 C(mol/l) η s p 40 60 80 100 FIG -10 0.00 0.05 0.10 0.15 0.0000 0.0004 0.0008 0.0012 0.0016 C(mol/l) η s p 40 60 80 100 FIG -11 0.00 0.05 0.10 0.15 0.0000 0.0004 0.0008 0.0012 0.0016 C(mol/l) η s p 40 60 80 100 FIG -12 0.00 0.05 0.10 0.15 0.0000 0.0004 0.0008 0.0012 0.0016 C(mol/l) η s p 40 60 80 100 FIG-7 1.5 1.6 1.7 1.8 1.9 2.0 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) Φ 40 60 80 100 FIG-8 1.5 1.6 1.7 1.8 1.9 2.0 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) Φ 40 60 80 100 FIG -9 0.00 0.05 0.10 0.15 0.0000 0.0004 0.0008 0.0012 0.0016 C(mol/l) η s p 40 60 80 100 FIG -10 0.00 0.05 0.10 0.15 0.0000 0.0004 0.0008 0.0012 0.0016 C(mol/l) η s p 40 60 80 100 FIG -11 0.00 0.05 0.10 0.15 0.0000 0.0004 0.0008 0.0012 0.0016 C(mol/l) η s p 40 60 80 100 FIG -12 0.00 0.05 0.10 0.15 0.0000 0.0004 0.0008 0.0012 0.0016 C(mol/l) η s p 40 60 80 100 Ecl. Quím., São Paulo, 35 - 2: 23 - 32, 2010 29 Artigo Article FIG-7 1.5 1.6 1.7 1.8 1.9 2.0 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) Φ 40 60 80 100 FIG-8 1.5 1.6 1.7 1.8 1.9 2.0 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) Φ 40 60 80 100 FIG -9 0.00 0.05 0.10 0.15 0.0000 0.0004 0.0008 0.0012 0.0016 C(mol/l) η s p 40 60 80 100 FIG -10 0.00 0.05 0.10 0.15 0.0000 0.0004 0.0008 0.0012 0.0016 C(mol/l) η s p 40 60 80 100 FIG -11 0.00 0.05 0.10 0.15 0.0000 0.0004 0.0008 0.0012 0.0016 C(mol/l) η s p 40 60 80 100 FIG -12 0.00 0.05 0.10 0.15 0.0000 0.0004 0.0008 0.0012 0.0016 C(mol/l) η s p 40 60 80 100 FIG-7 1.5 1.6 1.7 1.8 1.9 2.0 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) Φ 40 60 80 100 FIG-8 1.5 1.6 1.7 1.8 1.9 2.0 0 0.0004 0.0008 0.0012 0.0016 C(mol/l) Φ 40 60 80 100 FIG -9 0.00 0.05 0.10 0.15 0.0000 0.0004 0.0008 0.0012 0.0016 C(mol/l) η s p 40 60 80 100 FIG -10 0.00 0.05 0.10 0.15 0.0000 0.0004 0.0008 0.0012 0.0016 C(mol/l) η s p 40 60 80 100 FIG -11 0.00 0.05 0.10 0.15 0.0000 0.0004 0.0008 0.0012 0.0016 C(mol/l) η s p 40 60 80 100 FIG -12 0.00 0.05 0.10 0.15 0.0000 0.0004 0.0008 0.0012 0.0016 C(mol/l) η s p 40 60 80 100 fig. 9-12 Plot of ηsp versus C for compound A-D in benzene-methanol. The Moulik equation.17 also fits well to the solutions, as the plots (η/η0) 2 vs. C2 are almost linear. (η/ η0 )2 = m + KC2 Where M and K are constants. The values of M and K have been calcula- ted from the intercepts and slopes of the (η/η0) 2 vs. C2 plots and are recorded in Table-6. FIG - 13 1.5 2.0 2.5 3.0 3.5 4.0 0.000 0.010 0.020 0.030 0.040 0.050 C ψ / C 40 60 80 100 FIG - 14 1.5 2.0 2.5 3.0 3.5 4.0 0.000 0.010 0.020 0.030 0.040 0.050 C ψ / C 40 60 80 100 FIG - 15 2.0 2.5 3.0 3.5 4.0 4.5 0.000 0.010 0.020 0.030 0.040 0.050 C ψ / C 40 60 80 100 FIG - 16 2.5 3.0 3.5 4.0 4.5 5.0 0.000 0.010 0.020 0.030 0.040 0.050 C ψ / C 40 60 80 100 FIG - 17 1.0 1.1 1.2 1.3 1.4 1.5 0.0000000 0.0000005 0.0000010 0.0000015 0.0000020 C² (η /η ο) ² 40 60 80 100 FIG - 18 1.0 1.1 1.2 1.3 1.4 1.5 0.0000000 0.0000005 0.0000010 0.0000015 0.0000020 C² (η /η ο) ² 40 60 80 100 FIG - 13 1.5 2.0 2.5 3.0 3.5 4.0 0.000 0.010 0.020 0.030 0.040 0.050 C ψ / C 40 60 80 100 FIG - 14 1.5 2.0 2.5 3.0 3.5 4.0 0.000 0.010 0.020 0.030 0.040 0.050 C ψ / C 40 60 80 100 FIG - 15 2.0 2.5 3.0 3.5 4.0 4.5 0.000 0.010 0.020 0.030 0.040 0.050 C ψ / C 40 60 80 100 FIG - 16 2.5 3.0 3.5 4.0 4.5 5.0 0.000 0.010 0.020 0.030 0.040 0.050 C ψ / C 40 60 80 100 FIG - 17 1.0 1.1 1.2 1.3 1.4 1.5 0.0000000 0.0000005 0.0000010 0.0000015 0.0000020 C² (η /η ο) ² 40 60 80 100 FIG - 18 1.0 1.1 1.2 1.3 1.4 1.5 0.0000000 0.0000005 0.0000010 0.0000015 0.0000020 C² (η /η ο) ² 40 60 80 100 FIG - 19 1.0 1.1 1.2 1.3 1.4 1.5 0.000000 0 0.000000 5 0.000001 0 0.000001 5 0.000002 0 C² (η /η ο) ² 40 60 80 100 FIG - 20 1.0 1.1 1.2 1.3 1.4 1.5 0.000000 0 0.000000 5 0.000001 0 0.000001 5 0.000002 0 C² (η /η ο) ² 40 60 80 100 FIG - 19 1.0 1.1 1.2 1.3 1.4 1.5 0.000000 0 0.000000 5 0.000001 0 0.000001 5 0.000002 0 C² (η /η ο) ² 40 60 80 100 FIG - 20 1.0 1.1 1.2 1.3 1.4 1.5 0.000000 0 0.000000 5 0.000001 0 0.000001 5 0.000002 0 C² (η /η ο) ² 40 60 80 100 fig.17-20 Plot of [η/η0] 2 versus C2 for compound A-D in benzene-methanol. The viscosity data have also been interpre- ted in the light of Jones-Dole equation.18 (η/η0-1)/√C = A + B√C For convenience, the equation may be ex- pressed as ψ/√C = A + B√C Ecl. Quím., São Paulo, 35 - 2: 23 - 32, 201030 Artigo Article Where the coefficient A and B refer to so- lute-solute and solute-solvent interactions respec- tively. The plots ψ / √C vs.√C FIG - 13 1.5 2.0 2.5 3.0 3.5 4.0 0.000 0.010 0.020 0.030 0.040 0.050 C ψ / C 40 60 80 100 FIG - 14 1.5 2.0 2.5 3.0 3.5 4.0 0.000 0.010 0.020 0.030 0.040 0.050 C ψ / C 40 60 80 100 FIG - 15 2.0 2.5 3.0 3.5 4.0 4.5 0.000 0.010 0.020 0.030 0.040 0.050 C ψ / C 40 60 80 100 FIG - 16 2.5 3.0 3.5 4.0 4.5 5.0 0.000 0.010 0.020 0.030 0.040 0.050 C ψ / C 40 60 80 100 FIG - 17 1.0 1.1 1.2 1.3 1.4 1.5 0.0000000 0.0000005 0.0000010 0.0000015 0.0000020 C² (η /η ο) ² 40 60 80 100 FIG - 18 1.0 1.1 1.2 1.3 1.4 1.5 0.0000000 0.0000005 0.0000010 0.0000015 0.0000020 C² (η /η ο) ² 40 60 80 100 FIG - 13 1.5 2.0 2.5 3.0 3.5 4.0 0.000 0.010 0.020 0.030 0.040 0.050 C ψ / C 40 60 80 100 FIG - 14 1.5 2.0 2.5 3.0 3.5 4.0 0.000 0.010 0.020 0.030 0.040 0.050 C ψ / C 40 60 80 100 FIG - 15 2.0 2.5 3.0 3.5 4.0 4.5 0.000 0.010 0.020 0.030 0.040 0.050 C ψ / C 40 60 80 100 FIG - 16 2.5 3.0 3.5 4.0 4.5 5.0 0.000 0.010 0.020 0.030 0.040 0.050 C ψ / C 40 60 80 100 FIG - 17 1.0 1.1 1.2 1.3 1.4 1.5 0.0000000 0.0000005 0.0000010 0.0000015 0.0000020 C² (η /η ο) ² 40 60 80 100 FIG - 18 1.0 1.1 1.2 1.3 1.4 1.5 0.0000000 0.0000005 0.0000010 0.0000015 0.0000020 C² (η /η ο) ² 40 60 80 100 FIG - 13 1.5 2.0 2.5 3.0 3.5 4.0 0.000 0.010 0.020 0.030 0.040 0.050 C ψ / C 40 60 80 100 FIG - 14 1.5 2.0 2.5 3.0 3.5 4.0 0.000 0.010 0.020 0.030 0.040 0.050 C ψ / C 40 60 80 100 FIG - 15 2.0 2.5 3.0 3.5 4.0 4.5 0.000 0.010 0.020 0.030 0.040 0.050 C ψ / C 40 60 80 100 FIG - 16 2.5 3.0 3.5 4.0 4.5 5.0 0.000 0.010 0.020 0.030 0.040 0.050 C ψ / C 40 60 80 100 FIG - 17 1.0 1.1 1.2 1.3 1.4 1.5 0.0000000 0.0000005 0.0000010 0.0000015 0.0000020 C² (η /η ο) ² 40 60 80 100 FIG - 18 1.0 1.1 1.2 1.3 1.4 1.5 0.0000000 0.0000005 0.0000010 0.0000015 0.0000020 C² (η /η ο) ² 40 60 80 100 FIG - 13 1.5 2.0 2.5 3.0 3.5 4.0 0.000 0.010 0.020 0.030 0.040 0.050 C ψ / C 40 60 80 100 FIG - 14 1.5 2.0 2.5 3.0 3.5 4.0 0.000 0.010 0.020 0.030 0.040 0.050 C ψ / C 40 60 80 100 FIG - 15 2.0 2.5 3.0 3.5 4.0 4.5 0.000 0.010 0.020 0.030 0.040 0.050 C ψ / C 40 60 80 100 FIG - 16 2.5 3.0 3.5 4.0 4.5 5.0 0.000 0.010 0.020 0.030 0.040 0.050 C ψ / C 40 60 80 100 FIG - 17 1.0 1.1 1.2 1.3 1.4 1.5 0.0000000 0.0000005 0.0000010 0.0000015 0.0000020 C² (η /η ο) ² 40 60 80 100 FIG - 18 1.0 1.1 1.2 1.3 1.4 1.5 0.0000000 0.0000005 0.0000010 0.0000015 0.0000020 C² (η /η ο) ² 40 60 80 100 fig.13-16 Plot of ψ /√C versus √C for compound A-D in benzene-methanol. for the molecules studied here were found to be linear, with least scatter. These plots are cha- racterized by two straight lines intersecting at a point corresponding to the TCP of compounds. The values of TCP are in good agreement with the values derived from the plots of η, ηsp and φ vs. C. In view of the two intersecting straight lines for ψ / √C vs.√C plots, it is logical to evaluate two va- lues of both the coefficients below and above TCP designated as A1, B1 and A1, B1 respectively. Ecl. Quím., São Paulo, 35 - 2: 23 - 32, 2010 31 Artigo Article table – 6. Viscosity parameters in benzene – methanol derived from different equations compound % of methanol moulik equation jones-dole equation m1 m2 K1 K2 a1 a2 b1 b2 compound A 40% 1.069 1.143 307187 70036 1.407 2.102 83.566 36.505 60% 1.060 1.150 308995 62869 0.861 2.430 99.986 25.952 80% 1.064 1.139 246195 47155 1.552 2.587 58.107 8.589 100% 1.049 1.130 266636 34176 0.568 2.742 92.133 -6.651 compound B 40% 1.080 1.159 301055 68177 1.995 2.666 66.859 25.271 60% 1.066 1.152 331527 71956 1.003 2.268 105.700 36.054 80% 1.064 1.150 308373 48528 1.029 2.884 96.627 4.645 100% 1.049 1.137 272615 37966 0.581 2.804 93.413 -3.860 compound C 40% 1.078 1.202 409288 57418 0.877 4.100 144.87 -5.829 60% 1.078 1.197 409288 58197 0.898 4.496 139.79 -20.573 80% 1.071 1.195 363636 41453 1.018 4.349 117.09 -24.338 100% 1.059 1.180 333095 35690 0.866 4.350 104.72 -27.271 compound D 40% 1.096 1.243 445140 49099 1.610 5.564 134.880 -37.644 60% 1.086 1.217 427059 60826 1.271 4.865 136.160 -22.329 80% 1.077 1.224 411421 30275 0.966 5.589 137.170 -55.580 100% 1.071 1.193 359936 31496 1.193 4.977 108.730 -49.811 It is observed that the values of these constants depend on the composition of the solvent mix- tures. ConCluSion It has been observed that the viscosity of the system increases with the increase in concen- tration. The increasing trend of viscosity may be due to combined effect of the variation of dielec- tric constant of solvent, degree of aggregation and nature of the compound agglomerate. The TCP values obtained from different viscosity data are in good agreement and show maximum concentra- tion of molecular dispersion at which aggregation of molecule initiates. It is noteworthy to point out on the basis of results obtained that the above treatment gives a phenomenological description of clustering profi- le and confirms the existence of aggregation in the non-aqueous mixed solvent. references: M.Gracia, Valverde and T. Torroba, [1] Molecules, 10 (2005) 318. C. O. Kappe, [2] Terahedron, 49 (1993) 6937. T. Matsuda, J. Hirao, [3] Nippon Kagaku Zasshi, 86 (1965) 1195. Birgit Jauk, Tetiana Pernat and C. O. Kappe, [4] Molecules. 5 (2000) 227. C. O. Kappe, G. Farber, [5] J. Chem. 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