René D. Peralta

Volumetric Properties of Toluene with Ethyl Acrylate, Butyl Acrylate, Methyl Methacrylate, and Styrene at 25°C

Densities of the binary systems of toluene with ethyl acrylate, butyl acrylate, methyl methacrylate, and styrene have been measured as a function of the composition, at 25°C and atmospheric pressure, using an Anton Paar DMA 5000 oscillating U-tube densitometer. The calculated excess volumes were correlated with the Redlich–Kister equation and with a series of Legendre polynomials. The excess volumes are negative for systems toluene + (ethyl acrylate, butyl acrylate, and styrene) and positive for the system toluene + methyl methacrylate.

Volumetric Properties of Ethylbenzene with Ethyl Acrylate, Butyl Acrylate, Methyl Methacrylate, and Styrene at 298.15 K

Densities of the binary systems of ethylbenzene with ethyl acrylate, butyl acrylate, methyl methacrylate, and styrene have been measured as a function of the composition, at 298.15 K and atmospheric pressure, using an Anton Paar DMA 5000 oscillating U-tube densitometer. The calculated excess volumes were correlated with the Redlich-Kister equation and with a series of Legendre polynomials. The excess volumes are positive for the systems ethylbenzene + (methyl methacrylate, ethyl acrylate) and negative for the systems ethylbenzene + (butyl acrylate, styrene).

Electrostatic effects on the polymerization of vinyl acetate in three-component anionic microemulsions

The polymerization of vinyl acetate (VA) in three-component microemulsions stabilized with Aerosol OT is examined as a function of pH. To investigate the role of electrostatic effects on the polymerization kinetics, two initiators (potassium peroxodisulfate and V-50) that decompose into negatively-charged and positively-charged free radicals, respectively, were used. The pH of the reacting medium influences the efficiency of potassium peroxodisulfate (KPS) to initiate the reaction but it has no effect on V-50 efficiency. At neutral pH, faster reaction rates and higher conversions (after 90 min) are achieved with KPS. At equal free radical fluxes and pHs, KPS gives faster reaction rates and larger conversions than V-50 because of the different electrostatic interactions of KPS and V-50 free radicals with the negatively-charged microemulsion droplets and the reacting particles. Final latices contain nanosize polymer particles with particle size of ca. 30 nm in reactions initiated with KPS and between 26 and 40 nm in polymerizations initiated with V-50. In all cases, linear poly(vinyl acetate) is obtained because chain transfer to monomer is the controlling mechanism of chain growth, even at high conversions. This appears to be due to the small particle size that allows the fast desorption rate of the monomeric free radicals from the particles.

DENSITY, EXCESS VOLUMES, AND PARTIAL VOLUMES OF THE BINARY SYSTEMS OF ETHENYL ETHANOATE+BUTANOL, 2-BUTANOL, 2-METHYL-1-PROPANOL, AND 2-METHYL-2-PROPANOL AT 298.15 K

ABSTRACT Densities of the binary systems of ethenyl ethanoate (vinyl acetate) with 1-butanol,2-butanol (sec-butanol), 2-methyl-1-propanol (iso-butanol), and 2-methyl-2-propanol (tert-butanol) have been measured as a function of the composition, at 298.15 K and atmospheric pressure, using an Anton Paar DMA 5000 oscillating U-tube densimeter. The calculated excess volumes were correlated with the Redlich-Kister equation and with a series of Legendre polynomials. The excess volumes are positive for the four binaries and became larger as the alcohol becomes more branched.

Excess Molar and Partial Volumes of 2,2?-Oxybis[Propane] + Ethyl Acrylate, Butyl Acrylate, Methyl Methacrylate, and Styrene at 298.15 K

Densities of the binary systems of 2,2′-oxybis[propane] with ethyl acrylate, butyl acrylate, methyl methacrylate, and styrene have been measured as a function of the composition, at 298.15 K and atmospheric pressure, using an Anton Paar DMA 5000 oscillating U-tube densimeter and used to calculate the partial and excess volumes. The latter were correlated with the Redlich-Kister equation and with a series of Legendre polynomials. The excess volumes are negative for all the systems reported here.

Density and other thermodynamic properties of the binary systems of tetrahydrofuran + ethenyl ethanoate, methacrylic acid, butyl methacrylate, and allyl methacrylate at 298.15 K

Densities of the binary systems of tetrahydrofuran (THF) with ethenyl ethanoate (vinyl acetate), methacrylic acid, butyl methacrylate, and allyl methacrylate have been measured as a function of the composition, at 298.15 K and atmospheric pressure, using an Anton Paar DMA 5000 oscillating U-tube densimeter. The calculated excess volumes were correlated with the Redlich–Kister equation and with a series of Legendre polynomials. The excess volumes are negative for the three binaries methacrylic acid + tetrahydrofuran, butyl methacrylate + tetrahydrofuran, and allyl methacrylate + tetrahydrofuran, and become smaller as the solute becomes more branched or longer. Methacrylic acid exhibits substantially larger negative excess volumes probably due to hydrogen bonding with the solvent. The system tetrahydrofuran + vinyl acetate presents near ideal behavior.

Integration of hardware and software in a high‐performance laboratory reactor

1SYNOPSIS The assembly of a stirred tank reactor capable of precise reaction temperature control is described. The unit allows easy on-line determination of the thermal effect and calculation of heat transfer coefficients and heat capacities. Construction elements are standard, low cost, and high quality. Temperature control is achieved by a heating-cooling loop integrated to the reactor jacket and a cascade control procedure. An important feature of the equipment is the integration of the data acquisition system with the supervisory control system that allows the capability of an advanced strategy for process control and data acquisition. The capability of the reaction system is demonstrated for the microemulsion polymerization of vinyl acetate, by the use of batch and isothermal operational modes. The course of the reaction is followed on-line by the temperature variation of the jacket. Procedures are described for the calibration of the unit. The reactor developed is versatile, is easy to configure and extend, is low cost, and can compete advantageously with commercial reactor units such as the Mettler RC1. 0 1996 John Wiley & Sons, Inc.

DENSITIES AND DERIVED THERMODYNAMIC PROPERTIES OF THE BINARY SYSTEMS OF BENZENE WITH BUTYL METHACRYLATE, ALLYL METHACRYLATE, METHACRYLIC ACID, AND VINYL ACETATE AT 298.15 K

Densities of the binary systems of benzene with butyl methacrylate, allyl methacrylate, methacrylic acid, and vinyl acetate have been measured as a function of the composition, at 298.15 K and atmospheric pressure, using an Anton Paar DMA 5000 oscillating U-tube densimeter. The calculated excess molar volumes were correlated with the Redlich-Kister equation and with a series of Legendre polynomials. The excess molar volumes are positive for the four binaries studied.

Excess Molar Volume of 2,2′-Oxybis[propane] with Benzene, Toluene, Cyclohexane, and Methyl Ethanoate at 298.15 K

Abstract Densities of the binary systems 2,2′-oxybis[propane] with benzene, toluene, cyclohexane, and methyl ethanoate have been measured as a function of the composition, at 298.15 K and atmospheric pressure, using an Anton Paar DMA 5000 oscillating U-tube den-sitometer. The calculated excess volumes were correlated with the Redlich-Kister equation and with Legendres polynomials. The excess volumes are negative for the systems of 2,2′oxybis[propane] with benzene and toluene and positive with cyclohexane and methyl ethanoate.

Volumetric Properties of the Ternary System Dimethyl Carbonate + Butyl Methacrylate + Allyl Methacrylate and Its Binary Butyl Methacrylate + Allyl Methacrylate at 293.15 K and p=101.325 kPa

Densities of the ternary system dimethyl carbonate + butyl methacrylate + allyl methacrylate and its binary subsystem butyl methacrylate + allyl methacrylate have been measured in the whole composition range, at 293.15 K and atmospheric pressure, using an Anton Paar DMA 5000 oscillating U-tube densimeter. The calculated excess molar volumes of the binary system are positive and were correlated with the Redlich–Kister equation and with a series of Legendre polynomials. Several models were used to correlate ternary behavior from the excess molar volume data of their constituent binaries and found to fit the data equally well. The best fit was based on a direct approach, without information on the component binary systems.