Phase equilibria and physical properties of CO2-saturated cocoa butter mixtures at elevated pressures

Venter, MJ; Willems, P; Kareth, Sabine; Weidner, Eckhard; Kuipers, N.J.M.; Haan, de Ab André

doi:10.1016/j.supflu.2006.10.010

Cited by 32 publications

(14 citation statements)

References 26 publications

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“…This apparent selectivity increase can be attributed to the enhanced internal diffusion in the GXL medium, as the medium viscosity is considerably reduced by dissolution of carbon dioxide. Venter et al,15 for example, reported at 313 K a viscosity of ∼43 mPa s for cocoa butter and only 6 mPa s for CO 2 ‐saturated cocoa butter at 9 MPa. Given that the lipase is immobilized onto a porous support, diffusion is the prevalent mechanism for the transport of substrates towards the catalytic sites.…”

Section: Resultsmentioning

confidence: 99%

“…The increase in diffusivity can in turn enhance the equilibrium conversion, reaction rate, and/or selectivity in GXL as compared to solvent‐free or conventional organic media 7, 12, 13. For systems consisting of edible fats and carbon dioxide, several researchers have shown that considerable amounts of the gas are dissolved in the molten fat at moderate pressures,14, 15 which is accompanied by a decrease of the mixture viscosity 15…”

Section: Introductionmentioning

confidence: 99%

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Integrated synthesis and extraction of short‐chain fatty acid esters by supercritical carbon dioxide

et al. 2009

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We developed an efficient, integrated reaction‐extraction process for the production of short‐chain fatty acid ethyl esters (FAEE) from milk fat, using carbon dioxide as the only processing solvent. FAEE were synthesized using a short‐chain fatty acid selective lipase. The expansion of the liquid mixture of reactants by dense carbon dioxide enhanced the apparent lipase selectivity. In situ extraction of FAEE by a continuous flow of supercritical carbon dioxide proved to increase the lipase production rate. When the integrated process was operated with alternated periods of synthesis and product removal, the overall selectivity for short‐chain FAEE increased as well, as a result of the combination of the selectivities of lipase and extraction solvent. A two‐fold increase of the lipase productivity was achieved at these conditions, compared to a single batch reaction. The developed process enables the synthesis and isolation of high‐value fatty acid derivatives from a natural source such as milk fat. © 2009 American Institute of Chemical Engineers AIChE J, 2009

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Integrated synthesis and extraction of short‐chain fatty acid esters by supercritical carbon dioxide

et al. 2009

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“…In addition, CB viscosity was measured with the falling ball viscometer for temperatures from 313.15 to 353.15 K and at atmospheric pressure ( Table 2). The results obtained were compared with literature data [13] and rheological measurements (Fig. 5).…”

Section: Validation Of the Experimental Techniquementioning

confidence: 94%

“…In all applications, the addition of a miscible dense fluid such as scCO 2 will tend to enhance transport properties. Various methods can be used to measure the viscosity of fluids under high pressure: capillary [10,11], vibrating wire [12], quartz [13], rotational [14] and falling body [15][16][17][18][19][20][21][22][23][24][25] viscometers. The latter have been used to measure the high-pressure viscosity of hydrocarbons [15,16], oils [17,18] and binaries composed of CO 2 and polymer solutions [19][20][21] or organic solvents [22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Development of an improved falling ball viscometer for high-pressure measurements with supercritical CO2

Calvignac

Rodier

Letourneau

et al. 2010

The Journal of Supercritical Fluids

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This study presents the development of an improved technique for viscosity measurements under high pressure. The apparatus is based on the principle of the falling ball viscometer, implemented in a highpressure autoclave fitted with visualisation windows. The originality here is that the balls fall through a tube open at both ends with a diameter slightly greater than that of the balls, allowing a simplified modelling and numerical simulation. A numerical approach has been used for viscosity determination. Calculations have been made with COMSOL Multiphysics ® with the laminar Navier-Stokes model for Newtonian mixtures. It includes the specific hydrodynamic effects without the need for a calibration fluid. However, validation experiments were carried out at atmospheric pressure with dimethylsulfoxide (DMSO) at 298, 308 and 318 K and with cocoa butter at 313 and 353 K, with values of viscosity in the range from 1.4 to 45.4 mPa s. Comparative measurements with literature data have been conducted with cocoa butter saturated with carbon dioxide at 313 and 353 K and for pressures ranging from 0.1 to 25 MPa. At 313 K, viscosity varies from 45.4 mPa s to 3.1 mPa s while at 353 K it varies from 12.4 to 1.9 mPa s. For both isotherms tested, within the range 0-15 MPa, the higher the CO 2 dissolution in the cocoa butter, the lower the viscosity. However, this decrease in viscosity is more pronounced at the lowest temperature. Above 15 MPa the CO 2 dissolution effect on viscosity becomes insignificant, i.e. within the experimental error, due to a counter effect linked with the high hydrostatic pressure. Furthermore, the limits of use of this method have been determined. This technique is revealed as reliable and can therefore be used with other binary systems.

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“…Binary experimental data have also been reported for supercritical carbon dioxide mixed with industrial materials such as canola oil 68 and also with cocoa butter. 69 Other mixtures, for which saturated liquid densities have been reported, usually include a refrigerant. For example, Akasaka et al 70 reported the saturated liquid density of (2,3,3,3-tetrafluoropropane þ difluoromethane) in the vicinity of the critical point.…”

Section: Pure Substancesmentioning

confidence: 99%

Chapter 10. Saturated Liquid Density of Pure Liquids and of Mixtures

Takagi¹,

Tsuji²

2014

Volume Properties

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The vapour-liquid equilibrium of pure liquids and of their mixtures, together with the saturated liquid densities, constitute important thermodynamic properties in the understanding of matter. As a consequence, research into saturated liquid densities of operating fluids is very active and many papers have reported on pure saturated liquid densities and on the densities of mixtures. These experimental results have been fitted by empirical equations like the Tait equation, 1 and various kinds of equations of state. A summary of the research on the equilibrium properties of fluids is described by Poling et al. 2 In our previous studies, the saturated liquid density and related properties were widely investigated for pure liquids and mixtures and the data were utilised for the estimation of other physical properties and process design like heat pumps and refrigerators. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] In this chapter, we describe the latest experimental research and trends in saturated liquid densities of pure liquids and of liquid mixtures. Furthermore, the equations of state used to estimate saturated liquid density estimations are reviewed.Volume Properties: Liquids, Solutions and Vapours Edited by Emmerich Wilhelm and Trevor M. Letcher

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Phase equilibria and physical properties of CO2-saturated cocoa butter mixtures at elevated pressures

Cited by 32 publications

References 26 publications

Integrated synthesis and extraction of short‐chain fatty acid esters by supercritical carbon dioxide

Integrated synthesis and extraction of short‐chain fatty acid esters by supercritical carbon dioxide

Development of an improved falling ball viscometer for high-pressure measurements with supercritical CO2

Chapter 10. Saturated Liquid Density of Pure Liquids and of Mixtures

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