The standard molar enthalpy of formation for trimellitic acid (TMAc) in the crystalline phase at 298.15 K, ΔfHm°(cr), was calculated experimentally from combustion through calorimetry experiments. Likewise, sublimation determined fusion and vaporization differential scanning thermogravimetry, respectively. Subsequently, enthalpies gas-phase ΔfHm°(g), were calculated. TMAc, hemimellitic, trimesic acids predicted using multiple linear regression (MLR) with a nonreplacement evaluation...

In order to understand the influence that position of nitro group on aromatic ring has relative stability two isomers, standard enthalpies formation 3- and 4-nitrophthalic anhydride in gaseous phase, at T = 298.15 K, were obtained by experimental thermochemistry theoretical studies. The crystalline combustion calorimetry sublimation Knudsen method. For calculations, a ab initio molecular orbital method G3 level was used. phase from atomization isodesmic reactions. A study electronic...

Biopolymers have undergone growing development in the last twenty‐five years because of their important applications several areas medicine. Monomers Bis‐GMA and MMA are widely used either teeth restoration or complete substitution, respectively. This work reports design synthesis allyl‐3,5 bis(((allyloxy)carbonyl)oxy)benzoate (35DACBzA) its evaluation as an eluent for dental resin composites a crosslinking agent MMA. The formulated with monomer 35DACBzA showed polymerization shrinkage 40%...

In this research, both the standard molar enthalpy of formation in crystalline phase and gas 3-methylglutaric anhydride was calculated from experimental data. The temperature fusion, as well heat capacity solid by differential scanning calorimetry; sublimation at 298.15 K Knudsen effusion method, vaporization thermogravimetric analysis, massic combustion energy adiabatic calorimetry. Since 3,3-dimethylglutaric presented crystal transitions (with endothermic points 352.76 K, 356.98 397.15 K),...

In this investigation thermochemical properties of 3-hydroxyphthalic anhydride were determined. Fusion enthalpy, fusion temperature and molar heat capacity in solid phase obtained by differential scanning calorimetry. By the Knudsen effusion method, enthalpy sublimation at 298.15 K was obtained. thermogravimetric data, it possible to determine vaporization. On other hand, formation determined combustion The gas calculated from K. This experimental value compared both theoretical using...

Experimentally, the standard molar enthalpy of formation in crystalline phase at 298.15 K, Δ

The influence in addition order of monomers for the polymerization reaction polyamide imide (PAI), at a 1:1 molar ratio TMA:MDI NMP as solvent was studied thoroughly. In first instance, chemical structure PAI obtained using FTIR, 1H-NMR and Elemental analysis. On other hand, kinetic followed by viscosimetry (measuring instantaneous intrinsic viscosities different times), carried out on three synthesis routes proposed 140 ℃ 24 h reaction: a) MDI / solution to later add TMA, b) TMA c) MDI,...

Abstract Thermal crosslinking of polyimides is a relevant methodology to increase their chemical resistance. This reaction induced by heating after polymerization. Although this considered viable route modify polyimides, there controversy over the specific temperature for reaction. To contribute knowledge crosslinked structures, we performed differential scanning calorimetric (DSC) and solubility test studies on series with different molar ratios carboxylic acid groups. With...

La inteligencia artificial (IA) está cambiando el modo de ver la tecnología a nivel mundial. Desde su aplicación en los diversos asistentes voz hasta uso apps teléfonos celulares, IA es un tema que tomando gran relevancia debido beneficios ha mostrado avance tecnológico sectores industria y ciencia. Además, del procesamiento lenguaje natural, visión computacional robótica, dos las ramas más relevantes son machine learning o aprendizaje automático deep profundo. En general, objetivo común...

We have carried out the synthesis of a series chitosan-based membranes by casting solution method. The were synthesized from commercial chitosan and glycerin as plasticizer, varying concentration to determine that allows formation with best physicochemical properties retentate permeating test molecules. Formed cross-linked sulfuric acid, tested in permeation sodium chloride, saccharose whey protein. characteristics membrane evaluated water swelling factor, viscous molecular weight DSC....

Ocean-atmospheric interactions have effects at different scales; forming microclimates, which can explain variations with climatic or natural anomalies, between meteorological processes. This research analyzes and identifies the relationship of teleconnection hydrometeorological effects, determine distribution precipitation in corn yield. The data were used from a semi-structured interview directed to producers, where seven years case studies identified for eastern region state Puebla,...