Abstract

Background: A perusal of literature survey reveals that a number of transition metal soaps and their complexes have been studied however scanty references are available as to the investigation of copper (II) soap-complexes. The present study also gives an account of our understanding of several aspects of micelle formation of copper soapcomplexes in the mixed non-aqueous solvents. Attempts have also been made to study the physico-chemical properties of Cu(II) soap-complexes in methanol + benzene solvent mixtures and the findings has been reported in this paper.

Objective: Owing to proven industrial utility of copper (II) soap complexes, the paper provide a fundamental and informative account of micellar features of three complexes in 40% methanol-benzene and 80% methanol-benzene solvent mixture. The complexes synthesized are abbreviated as follows:

(1) Copper-caprylate with 2-amino-6-methyl benzothiazole: CCplAMB

(2) Copper-caprate with 2-amino-6-methyl benzothiazole: CCprAMB

(3) Copper-laurate with 2-amino-6-methyl benzothiazole: CLrtAMB

Method: The density, molar volume, and apparent molar volume of Cu (II) surfactants with substituted 2-amino-6-methyl benzothiazole in 80 % and 40% benzene-methanol mixture has been determined at constant temperature 298.15 K.

Results: The results were used to determine the Critical Micelle Concentration (CMC), the effect of chain length of the complex molecule on CMC and complex-solvent interactions. The CMC decreases with the increase in the chain length of fatty acid segment of complex. The apparent molar volume has been examined in terms of Masson equation, and the limiting apparent molar volume has been interpreted in terms of solute-solvent interaction. The solute – solute interactions were found to be greater before CMC whereas solute solvent interactions were found greater after CMC. There is appreciable increase in aggregation of surfactant molecules at a definite concentration and the structure of the aggregates is entirely different below and above CMC. The effect of polarity of the solvent has also been studied.

Conclusion: The current topic will contribute to understand the solution behavior, micellar characters and different interactions which exist between solute-solute and solute-solvent molecules for their applications in various fields.

Keywords: 2-Amino-6-methyl benzothiazole, benzene, CMC, copper, surfactants, soap-complexes.

Graphical Abstract