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Title:	Structure property relationship of surfactants using modified oleic acid
Authors:	Larry Lee Mook Swee (P42246)
Supervisor:	Mohd. Ambar Yarmo, Prof. Dr.
Keywords:	Oleic acid Surface active agents Universiti Kebangsaan Malaysia -- Dissertations Dissertations, Academic -- Malaysia
Issue Date:	27-Feb-2014
Description:	Of late there has been considerable interest in studying the structure property relationships of surfactants. This research extends this interest by derivatizing fatty acids and converting it to surfactants by bromination of the unsaturation at C9 or C10 of the oleic acid chain and studying its effect on surface activity. A single bromine derivative, sodium 10-bromo stearic acid have been synthesized by reacting with hydrogen bromide in acetic acid. This reaction was driven up to 98% completion by using different solvent effects and molar ratios of reactants. The rate of reaction was also studied. The bromination was further extended by the addition of another bromine to this unsaturation to produce sodium 9,10-dibromo stearic acid. The effects of these modifications on the surface properties like critical micelle concentration (CMC), surface excess concentration and minimum area`per molecule were studied. The results indicate that because of bromination of the hydrophobic chain, the minimum area per molecule increased, the CMC increased and micellization was suppressed. Adsorption at the air water interface however was not much affected as the surface tension at CMC was almost the same. In fact, bromination increased the efficiency of the surfactant in reducing surface tension. The effect of this structural change on the foaming properties was also studied. It was found that foamability of the brominated analogues was not affected, however its foam were found to be less stable. Bromination also caused the coalescence and bursting of large bubbles. The effect of bromination on non ionic surfactants was also studied by changing the anionic head group to glycol esters. Bromination has been shown here to be able to change the partition coefficient of non ionic surfactants in a hexane water mixture. This change allowed the formation of a thick gel emulsion of water in oil instead of the usual oil in water emulsion. An application of these brominated surfactants was investigated for use as a fracturing fluid in fracturing rock formations in oil field. Potassium oleate as a viscoelastic surfactant gives a low partition coefficient when in contact with hydrocarbon. Bromination of the oleate chain has been shown in this work to increase the partition coefficient and still maintaining its viscoelasticity. The partition coefficient increased to 13.2% for a 5% solution compared to negligible for potassium oleate. This facilitates the removal of the surfactants after its use as a fracturing fluid. The viscoelastic properties were demonstrated using a Bohlin rheomter. Other derivatives of the oleic acid hydrophobic chain were made and synthesized using the brominated analogues as a starting material and using the fact that bromine is a good leaving group viz, sodium 10-amino stearic acid, sodium 9,10-diamino stearic acid, steorolic acid and 10-bromo oleic acid.,Certification of Master's / Doctoral Thesis" is not available
Pages:	166
Call Number:	TP994.L346 2014 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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