Methods for determining the vapour pressure of active ingredients used in crop protection. Part IV. An improved thermogravimetric determination based on evaporation rate

Gückel, W.; Kästel, Roland; Kröhl, Thomas; Parg, Adolf

doi:10.1002/ps.2780450105

Cited by 25 publications

(19 citation statements)

References 5 publications

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“…TGA provides a fast and reliable method to study a number of compounds that are thermally stable up to their melting point at ambient pressure [27,29]. Using this method, the evaporation rate of a compound determined under isothermal conditions is directly related to its vapor pressure [27][28][29][30][31].…”

Section: Sublimation Pressurementioning

confidence: 99%

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Catechin sublimation pressure and solubility in supercritical carbon dioxide

Soetaredjo¹,

Ismadji²,

Yuliana³

et al. 2013

Fluid Phase Equilibria

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a b s t r a c tSolubility of (+)-catechin in SC-CO 2 was measured at several temperatures (313.15, 323.15, 333.15 and 343.15 K) and pressure in the range of 12-26 MPa using ethanol as the co-solvent (5 mol.%). The experimental data were used for the correlation of density dependent solute solubility parameters. The equations of Chrastil, del Valle and Aguilera, Adachi and Lu, González, and Méndez-Santiago and Tejawere fitted very well for the solubility of (+)-catechin. The rate of mass loss of (+)-catechin showed that its sublimation pressure is very low, an indication of the stability of the compound. Thermogravimetric analysis was used to determine the sublimation pressure.

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Section: Sublimation Pressurementioning

confidence: 99%

“…In addition, it can be used to study its phase transitions such as sublimation and the related properties such as vaporpressure [27][28][29]. TGA provides a fast and reliable method to study a number of compounds that are thermally stable up to their melting point at ambient pressure [27,29].…”

Section: Sublimation Pressurementioning

confidence: 99%

Catechin sublimation pressure and solubility in supercritical carbon dioxide

Soetaredjo¹,

Ismadji²,

Yuliana³

et al. 2013

Fluid Phase Equilibria

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“…This method requires the sample to be at least 95% pure 5 and without substantial amount of residue solvent or other volatile impurities. Being 99% pure with little volatile impurities, the DPC 963 drug substance clearly satisfied the purity requirements.…”

Section: Determination Of Sublimation Ratementioning

confidence: 99%

Sublimation characterization and vapor pressure estimation of an HIV nonnucleoside reverse transcriptase inhibitor using thermogravimetric analysis

2003

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KEYWORDS: sublimation, vapor pressure, thermogravimetric analysis-infrared (TGA-IR) The purpose of this research is to investigate the sublimation process of DPC 963, a second-generation nonnucleoside reverse transcriptase inhibitor for HIV-1 retrovirus, and to better understand the effect of sublimation during active pharmaceutical ingredient (API) manufacture and formulation development, especially the drying processes. Sublimation of DPC 963 at 150°C and above was determined by thermogravimetric analysis-Fourier transform infrared (TGA-FTIR). The rates of sublimation at different temperatures were measured using isothermal TGA. Condensed material was collected and analyzed by differential scanning calorimetry (DSC), x-ray powder diffraction (XRPD), and infrared (IR) spectrometry. Benzoic acid was used as a reference standard to derive a linear logarithmic relationship between sublimation/evaporation rate and vapor pressure specific to the TGA system used in this study. Sublimation and evaporation of DPC 963 were found to follow apparent zero-order kinetics. Using the Eyring equation, the enthalpy and entropy of the sublimation and evaporation processes were obtained. The enthalpies of sublimation and evaporation were found to be 29 and 22 kcal/mol, respectively. The condensed material from the vapor phase was found to exist in 2 physical forms, amorphous and crystalline. Using benzoic acid as a reference standard, vapor pressure of DPC 963 at different temperatures was calculated using the linear logarithmic relationship obtained. DPC 963 undergoes sublimation at appreciable rates at 150°C and above but this is not likely to pose a serious issue during the manufacturing process. Vapor pressure estimation using thermogravimetric analysis provided sufficient accuracy to be used as a fast, simple, and safe alternative to the traditional methods of vapor pressure determination.

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“…For the same gas flow rate, the calibration factors depended on measuring temperature [18]. Later work extended the temperature range by using a thermobalance which correlated the mass loss rate per unit area (g h À1 cm À2 ) with the vapour pressure over a wide temperature range to derive a similar log-log relationship [19]. A further refinement incorporated a form of evolved gas analysis whereby the exhaust from the thermobalance was passed through a trap and subsequently examined to determine the fractional evaporation and degradation of the volatilising species [20].…”

Section: Introductionmentioning

confidence: 99%

“…Of particular interest was a series of papers by Gückel et al who measured the volatilisation rates of pesticides at ambient pressure by isothermal thermogravimetry [16][17][18][19]. Their initial studies employed a thermostatically-housed balance purged with a pre-heated air stream from which they established a double logarithmic relationship between the rate of amount of substance lost per unit area (expressed as mol h À1 cm À2 ) and the material's vapour pressure [16].…”

Section: Introductionmentioning

confidence: 99%

A fit of the vapours

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2015

Thermochimica Acta

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Methods for determining the vapour pressure of active ingredients used in crop protection. Part IV. An improved thermogravimetric determination based on evaporation rate

Cited by 25 publications

References 5 publications

Catechin sublimation pressure and solubility in supercritical carbon dioxide

Catechin sublimation pressure and solubility in supercritical carbon dioxide

Sublimation characterization and vapor pressure estimation of an HIV nonnucleoside reverse transcriptase inhibitor using thermogravimetric analysis

A fit of the vapours

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