Refractive indexes of ethane, carbon dioxide, and isobutane

Besserer, George J.; Robinson, Donald B.

doi:10.1021/je60057a033

Cited by 59 publications

(34 citation statements)

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“…The values of A 11 for gold, [33] e (3.91) and n (1.45) were taken from the literature. [36,37] The strong pressure-dependent Hamaker constant demonstrates the ability to describe adsorption of the nanoparticles into the channels of the mesoporous silica support in the compressed fluid medium. The Hamaker constant for the gold-silica interaction decreases (0.858 eV to 0.291 eV) considerably with the increase in the CO 2 pressure from 7 to 17 MPa.…”

Section: Resultsmentioning

confidence: 99%

In situ Synthesis of Gold Nanoparticles inside the Pores of MCM‐48 in Supercritical Carbon Dioxide and its Catalytic Application

et al. 2006

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Gold nanoparticles are deposited into the channels of MCM-48 through a simple H 2 -assisted reduction of HAuCl 4 (aqueous solution) in supercritical carbon dioxide medium at 70 8C within 2-4 h. The nanoparticles were characterized by powder Xray diffraction (PXRD), N 2 adsorption-desorption, transmission electron microscopy (TEM), and UVVis spectroscopy. The particle size of the synthesized material is tunable with the pressure (density) of the supercritical carbon dioxide medium. At the fixed temperature (70 8C) and hydrogen pressure [P(H 2 ) = 2 MPa], the Au particle size varies from ca. 25 nm to ca. 2 nm with the change in CO 2 pressure from 7 MPa to 17 MPa. At the low solvent density conditions, larger particles of~25 nm were obtained. On the contrary, a high solvent density of CO 2 slows down particle aggregation, resulting in the small particle size within the range of 2-5 nm. This change in particle size with CO 2 pressure and the interaction of the particles with the silica support were correlated well with long-range van der Waals interactions and consequently the Hamaker constant for the gold nanoparticle-CO 2 (A 131 ) and silica-gold core-CO 2 (A 132 ), respectively. Supercritical carbon dioxide alone can provide a unique environment for stabilizing gold nanoparticles in the channels of the cubic mesoporous MCM-48 support and exquisite control of the particle size without perturbing the support structure. The synthesized material is highly stable, recyclable and no metal nanoparticle leaching was observed. The selective hydrogenation of crotonaldehyde with the synthesized material provides convincing evidence that the particles are inside the pores and available to the reactant molecules.

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Section: Resultsmentioning

confidence: 99%

In situ Synthesis of Gold Nanoparticles inside the Pores of MCM‐48 in Supercritical Carbon Dioxide and its Catalytic Application

et al. 2006

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“…Experimental data on the solubility of CO 2 in water and the RI of dense CO 2 , over a wide range of temperature and pressure, are available in the literature. 50,56 Using this information, in combination with the density of CO 2 , 47 eqn (2) can be used to estimate the RI of the continuous phase at P T . The results for the three vinyl monomers discussed above are summarised in Table 2.…”

Section: Mechanism Of Miniemulsion Transparencymentioning

confidence: 99%

Radical polymerization of miniemulsions induced by compressed gases

et al. 2016

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Generation of miniemulsions (nanoemulsions) comprising hydrophobic vinyl monomers and water by use of the compressed gases carbon dioxide and ethylene, respectively, has been investigated in the absence of high energy mixing. It is proposed that transparent/translucent miniemulsions are formed at the transparency pressure (P T ) as a result of the refractive index of the dispersed phase being reduced due to expansion with carbon dioxide/ethylene, resulting in refractive index matched miniemulsions with enhanced stability. Radical polymerization of methyl acrylate at 40 C in miniemulsions induced by carbon dioxide at P T proceeds as a hybrid miniemulsion/emulsion polymerization system generating particles with diameters less than 100 nm. The experimental data are consistent with particle formation occurring mainly via monomer droplet nucleation (miniemulsion polymerization) but also via secondary nucleation in the aqueous phase (emulsion polymerization). Polymerizations at a range of pressures above and below P T revealed limited pressure effects on the polymerization rate and particle size for both carbon dioxide and ethylene.

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“…The refractivity R 0 LL ¼ 6:6447, for CO 2 at the wavelength 632.8 nm, was obtained from reference (Stoll, 1922). Coefficients B ¼ 1:10 and C ¼ À265 were obtained by analyzing data given in references (Michels and Hamers, 1937;Besserer and Robinson, 1973) by plotting ðR LL À R 0 LL ÞV versus 1=V. The CO 2 density is taken from International Thermodynamic Tables of the Fluid State 3 (1976).…”

Section: Pure Comentioning

confidence: 99%

“…Although this technique is highly accurate, it is complex to operate and also unsuitable for dynamic processes such as mixing or separation in which n s can fluctuate. Minimum-angle-of-deviation method (Besserer andRobinson, 1971, 1973) makes use of an autocollimating refractometer with overall possible error of approximately 10 7 4 . This method requires relatively long measurement time (minutes per data point) and very elaborate optical cell design with an internal mirror.…”

Section: Introductionmentioning

confidence: 99%

“…A beamdisplacement technique (Kirby and McHugh, 1997) gives the advantage of simple experimental design but may, however, lack accuracy, as a typical error is about 10 7 2 . To date, the refractive index of pure CO 2 has been measured using these techniques at temperatures between 298 and 373 K and at pressures up to 2400 bar (Michels and Hamers, 1937), temperatures between 323 and 373 K and pressures up to 230 bar (Adjoury et al, 1997), and temperatures between 310 and 394 K and pressures up to 102 bar (Besserer and Robinson, 1973). In addition, n s of CO 2 -n-butane system was measured at 310 K and pressures up to 80 bar (Besserer and Robinson, 1971).…”

Section: Introductionmentioning

confidence: 99%

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Refractive index of supercritical CO 2 -ethanol solvents

Sun

Shekunov

York³

2003

Chemical Engineering Communications

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In-line analysis of refractive index is required for efficient design and monitoring of supercritical fluid extraction and precipitation processes. In the present work, a robust method has been developed based on measurements of laser beam deviation using an interferometer and image processing system. Data on refractive index of CO 2 -ethanol mixtures were obtained at pressures between 70 and 200 bar and temperatures between 308 and 363 K, for continuous flow of premixed solvents and, in addition, for equilibrium gas phase below the mixture critical pressure. The refractive index of a mixture is a linear function of ethanol mole fraction and can adequately describe mixing and phase behavior in the vessel. For pure CO 2 , refractive index was determined as a function of pressure and density and its Lorentz-Lorenz functions determined.

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Refractive indexes of ethane, carbon dioxide, and isobutane

Cited by 59 publications

References 0 publications

In situ Synthesis of Gold Nanoparticles inside the Pores of MCM‐48 in Supercritical Carbon Dioxide and its Catalytic Application

In situ Synthesis of Gold Nanoparticles inside the Pores of MCM‐48 in Supercritical Carbon Dioxide and its Catalytic Application

Radical polymerization of miniemulsions induced by compressed gases

Refractive index of supercritical CO 2 -ethanol solvents

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