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Separation of oil-in-water emulsions using fiber bed coalescer was studied by response surface methodology. The bed was formed of polyethylene terephthalate fibers. The aim was to investigate the possibility of using response surface regression for the analysis and prediction of both the effluent oil concentration and critical velocity in broad ranges of flow rates, bed permeabilities, and nature of dispersed oil phase. The developed response surface equations for a constant bed permeability are a responsive statistical method with the calculated multiple R higher than 90%. It was found that dispersed oil density, viscosity, neutralization number, and bed permeability influence significantly the oil removal efficiency of fiber bed coalescers. The region of highest critical velocity has been observed for a high viscosity and a high fiber bed permeability. The developed response surface models can be used to ensure high separation efficiency and improve coalescer performance when unexpected simultaneous changes in the bed permeability, hydrodynamic forces and dispersed oil properties take place. [Projekat Ministarstva nauke Republike Srbije, br. 172022]

The liquid-liquid equilibrium constant for acetic acid in a quinary system olive oil-epoxidized olive oil-acetic acid-hydrogen peroxide-water was experimentally determined for temperatures and component ratios relevant for in situ epoxidation of plant oils. The values has the constant range from 1.52 to 2.73. To predict the equilibrium constant for acetic acid, the experimental data were correlated with UNIQUAC (universal quasi chemical) and NRTL (non-random two liquid) activity coefficient models. For simplified calculation of the phase equilibrium the insolubility of olive oil and epoxidized olive oil in the water, as well as insolubility of water and hydrogen peroxide in the olive oil and epoxidized olive oil, was assumed. The root mean square deviation (RMSD) of the experimental and calculated values of the liquid-liquid equilibrium constant for acetic acid is 0.1910 for the UNIQUAC model and 0.1815 for the NRTL model. For rigorous flash calculation, when the partitioning of all components between the phases was assumed, the RMSD for the NRTL model is 0.1749. [Projekat Ministarstva nauke Republike Srbije, br. 45022]

Mathematical models that describe the kinetics of reaction systems for the in situ epoxidation of unsaturated fatty acid esters or triglycérides with organic peracids are reviewed in this paper. The advantages and inadequacies of each model are discussed. A mono-phase pseudo-first order kinetic model was compared with a two phase model based on the Langmuir-Hinshelwood-Hougen-Watson (LHHW) postulates proposed by the authors of this paper. The comparison was performed on the experimentally determined values for the in situ epoxidation of soybean oil by peracetic acid in the presence of different quantities of ion exchange resin used as the catalyst. It was concluded that a complete model for in situ epoxidation in the presence of ion exchange resin as the catalyst was still not given for perorganic acid formation. In particular, we report here the possibilities of the creation of an "ideal" model for in situ epoxidation.

Biindenylidene isomers are components of pyrolysis oils. The mass spectra were recorded and the fragmentation of the following biindenylidene isomers (E)-2,3,2’,3’-tetrahydro- [1,1’]biindenylidene (Z)-2,3,2’,3’-tetrahydro-[1,1’]biindenylidene 1,3,1’,3’-tetrahydro-[2,2’]biindenylidene and 2,3,1’,3’-tetrahydro-[1,2’]biindenylidene, as well as of spiro[1,1a,6,6a-tetrahydrocyclopropa [a]indene-1,1’-2’,3’-dihydro-1’H-indene]is discussed.

Thekinetics of the epoxidation of castor oil in benzene with peraceticacid formed in situfrom acetic acid and hydrogenperoxide in the presence of an ion-exchange resin as a catalyst wasstudied. Eighteen pseudo-two-phase models are established that, besidesthe main reactions of peracid and epoxy ring formation, also considerthe side reaction of epoxy ring cleavage with acetic acid. Kineticexpressions for the heterogeneously catalyzed peracetic acid formationare developed on the basis of Eley–Rideal and Langmuir–Hinshelwood–Hougen–Watsonpostulates. An equation derived for the temperature dependency ofthe chemical equilibrium constant for peracetic acid formation isapplied. Kinetic and adsorption parameters were estimated by fittingexperimental data using the Marquardt method. The best-fit model correctlyinterprets data of double bond and epoxy group contents as a functionof reactant ratios, catalyst concentrations, and temperatures appliedduring epoxidation. The proposed model better fits experimental datathan the pseudohomogeneous model reported in the literature. [ABSTRACT FROM AUTHOR]