Characterization of the Sublimation and Vapor Pressure of 2-(2-Nitrovinyl) Furan (G-0) Using Thermogravimetric Analysis: Effects of Complexation with Cyclodextrins

Abstract

Abstract:In the present work, the sublimation of crystalline solid 2-(2-nitrovinyl) furan (G-0) in the temperature range of 35 to 60 °C (below the melting point of the drug) was studied using thermogravimetric analysis (TGA). The sublimated product was characterized using Fourier-transformed-infrared spectroscopy (FT-IR) and thin layer chromatography (TLC). The sublimation rate at each temperature was obtained using the slope of the linear regression model and followed apparent zero-order kinetics. The sublimation enthalpy from 35 to 60 °C was obtained from the Eyring equation. The Gückel method was used to estimate the sublimation rate and vapor pressure at 25 °C. Physical mixtures, kneaded and freeze-dried complexes were prepared with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) and sulfobutyl ether-β-cyclodextrin OPEN ACCESSMolecules 2015, 20 15176(SBE-β-CD) and analyzed using isothermal TGA at 50 °C. The complexation contributed to reducing the sublimation process. The best results were achieved using freeze-dried complexes with both cyclodextrins.

Reducing the Sublimation Tendency of Ligustrazine through Salt Formation

“…Sublimation rate, obtained from the slop of the linear part of each isothermal TGA curve (Figure S5), are plotted against the reciprocal of temperature using the Arrhenius eq : where k is the sublimation rate, T is the absolute temperature (K), A is a constant for the specific reaction, and E a is the activation energy. This method was validated with benzoic acid since the measured E a (92.5 kJ/mol) was similar to that reported (90.9 ± 2.0 kJ/mol). , …”

“…This method was validated with benzoic acid since the measured E a (92.5 kJ/mol) was similar to that reported (90.9 ± 2.0 kJ/mol). 31,35 In contrast to the expected linear relationship between ln(k) and 1/T, which was observed in benzoic acid (Figure S4), all three salt hydrates show bilinear relationships (Figure 7). As discussed earlier, the rates at lower temperatures and zero RH correspond to the confounded effects of simultaneous sublimation and dehydration of these hydrates.…”

“…The thermodynamics of the sublimation of salts could be related to solubility, other thermal parameters, and intermolecular interactions. , Several approaches have been proposed to characterize sublimation behavior, including vapor pressure measurement techniques (e.g., effusion cell, gas saturation, and inclined-piston manometry), thermogravimetry, , and atomic force microscope (AFM) . Sublimation data can be analyzed using the Arrhenius equation, Eyring equation, or Clausius–Clapeyron equation to gain more understanding into the thermodynamics and kinetics of this process.…”

Evaluation of the Sublimation Process of Some Purine Derivatives: Sublimation Rate, Activation Energy, Mass Transfer Coefficients and Phenomenological Models

“…Thermogravimetric analysis is used to study the sublimation process, due to the simplicity of the method and the accurate measurement of mass variation with temperature. Most of the existing literature studies the determination of vapor pressure, the evaluation of the sublimation enthalpy and the sublimation rate [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. A Perkin-Elmer thermogravimetric analyzer was used by Dichi et al to determine the vapor pressure and enthalpy of caffeine sublimation [ 4 ].…”

Accurate or Fast Prediction of Solid-State Formation Enthalpies Using Standard Sublimation Enthalpies Derived From Geometrical Fragments

“…The sublimation enthalpy of a molecular crystal is one of its most fundamental properties. It is a valuable indicator of crystal stability and may be used to evaluate other properties of practical significance such as vapor pressure . Moreover, it is a significant contribution to the solid-state formation enthalpy Δ f H 0 (cr) of organic crystals required to evaluate the energy content, performances, and sensitivities of candidate materials of potential interest as components of fuels, propellants, or explosives. , Although Δ f H 0 (cr) may be estimated directly from molecular structure, i.e., without explicitly evaluating the gas-phase and sublimation enthalpies, such procedures are deprived of physical bases and rely mostly on empiricism. − Since the intra- and intermolecular contributions to Δ f H 0 (cr) depend on distinct interactions, they should ideally be evaluated separately.…”