Synthesis And Properties Of A New Gemini Surfactant From Rosin Derivative

To study and synthesize new surfactants which have high surface activity has always beenan interesting task of people.Gemini surfactants are made up of two amphiphillic moieties connecting at the level ofthe headgroups by chemical bonds. Because of its especial structure and characteristics,Gemini surfactant is a researching emphasis in the field of surfactant. In terms of molecularstructure, the special characteristics of Gemini surfactant solution are the associate result ofspacer group and hydrophobic group. At present the study on Gemini surfactants is mainlyfocused on the spacer group. The hydrophobic chain is mostly straight chain alkyl with 8-10carbon and the report about other hydrophobic chain such as aromaticity and hydrophobicgroup with hetero-atom was relatively less. Because the hydrophobic chain is difficult tosynthesize, separate and purify.To study the relationship between the hydrophobic "tail" structure and thecharacterizations of Gemini surfactants, a new gemini surfactant CsH2s-α,ω-bis(dehydroabietylhydroxypropylteteramethylethylammonium Chloride),here s=2, wassynthesized. Dehydrogenated rosin as hydrophobic "tails" in the structure. The impact factorsin the two steps are discussed. The optimal synthetical condition of 3-dehydroabietylacyloxyl-2-hydroxypropyl chloride was that the ratio of dehydroabietic acid to epichlorohydrin was 1 to2, the amount of catalyst was 1～1.5% of the system mass, the reaction temperature was 90℃and the reaction time was 3.5 h. The optimal synthetical condition of CsH₂s-α,ω-bis(dehydroabietylhydroxypropylteteramethylethylammonium Chloride),here s=2 is that withthe solvent of ethanol, the ratio of 3-dehydroabietylacyloxyl-2-hydroxypropyl chloride to N, N,N',N'-teramethylendiamin is 2.3:1, the reaction temperature was 90℃and the reaction timewas 2.5h. The structure of aimed gemini surfactant was characterized by IR, MS and elementanalysis.The surfactivity of the new gemini surfactant was investigated by UV-ViS andmensurating conductance and surface tension. The results showed that the surfactant canreduce water surface tension to 34.9 mN/m, and the CMC is 1.0×10^-4mol/L. It implied that theaimed gemini surfactant was more likely to form micellar with these two "tails" and had bettersurface activity. The CMC measured by UV-VIS was accorded with that measured byconductance and surface tension, which indicated that it was possible to determine the CMC ofby CsH₂s-α,ω-bis(dehydroabietylhydroxypropylteteramethylethylammonium Chloride),heres=2.In addition, the effect of temperature on the conductance was investigated. The micellar behavior of the bis-quatemary ammonium salt was studied.â–³G_m^θ,â–³H_m^θand -Tâ–³S_m^θwerecalculated. The results showed that the micellar behavior was spontaneous under standardstate, and it more easily took place at high temperature. The value of -Tâ–³S_m^θwas belowzero and less than that ofâ–³H_m^θ, which implied that the micellar behavior of CsH₂s-α,ω-bis(dehydroabietylhydroxypropylteteramethylethylammonium Chloride),here S=2 was mainlydrived by entropy.