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1.
Qualitative study of a well-stirred isothermal reaction model
Barbara Arcet, Maša Dukarić, Zhibek Kadyrsizova, 2020, original scientific article

Abstract: We consider a two-dimensional system which is a mathematical model for a temporal evolution of a well-stirred isothermal reaction system. We give sufficient conditions for the existence of purely imaginary eigenvalues of the Jacobian matrix of the system at its fixed points. Moreover, we show that the system admits a supercritical Hopf bifurcation.
Keywords: limit cycle, Hopf bifurcation, stability, reaction kinetics
Published in DKUM: 16.10.2023; Views: 329; Downloads: 38
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2.
Enzymatic fatty ester synthesis
Simona Pečnik, Željko Knez, 1992, original scientific article

Abstract: Fatty ester synthesis with immobilized 1,3-specific lipase from Mucor Miehei is described. 1,2-Isopropylidene glycerol was peoduced by condensation of glycerol with acetone was esterified with oleic acid in the presence of a Mucor Miehei lipaze (Lipozyme TM) to obtain 1,2 isopropylidene- 3-oleoyl glycerol. The effects of various process parameters (temperature and pressure)and various ratios (enzyme/substrate) have been investigated to determine optimal conditions for the esterification process. The highest conversion of oleic acid (80% w/w) was obtained at 55 oC and 57.057 bar, while the optimal addition of lipase to substrate was determined to be 0,096 g per gram of reaction mixture. The esterification can be modelled successfully as a reverse second order reaction. Thermodynamic properties of the reaction system at 55 oC and 0.057 bar were also determined. Activation energy was 20.82 kJ/mole, entropy of activation -0,26 kJ/(Kmole) and free energy of activation was 103.32 kJ/mole.
Keywords: chemical engineering, biotechnology, esterification, syntheses, esters, enzymes, lipase, Mucor miehei, reaction kinetics, reaction thermodynamics, 1, 2-isopropylidene-3-oleoyl glycerol
Published in DKUM: 06.06.2012; Views: 2549; Downloads: 102
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