ентальпія утворення

The formation of associates in aqueous solutions between single- or double-charged anions of 5,5′-dibromo-o-cresolsulfonphthaleine and single-charged cations of cyanine dyes (quinaldine blue, quinaldine red) has been considered. Based on the spectrophotometric data, the equilibrium constants of the association were analyzed. The energy of cation-anion interactions (standard enthalpy of formation of ions and associates) was determined by the semi-empirical AM1 method and probable structures of associates were set.

Combustion energies of esters (ethyl 6-methyl-2-oxo-4-phenyl-1,2,3,4-tetrahydropyrimidine-5-carboxylate; ethyl 6-methyl-4-(4-methylphenyl)-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate; ethyl 4-(4-methoxyphenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate and ethyl 4-(6-methoxyphenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate) were experimentally obtained using a bomb calorimetry. According to the experimental data, the enthalpies of combustion and the enthalpies of formation in a solid state were calculated.

Using the precision bomb combustion calorimeter B-08-MA, the combustion energies of 5- (2-nitrophenyl) -furan-2-carbaldehyde, 5- (2-nitro-4-methylphenyl) -furan-2-carbaldehyde and 5- ( 2-nitro-4-oxymethylphenyl) -furan-2-carbaldehyde. Based on the obtained data, the values of enthalpies of combustion and formation of substances in the condensed state are calculated. A comparative analysis of experimentally determined values with theoretically calculated values by additive calculation methods is given.

2-Cyano-3-[5-(2-oxy-methyl-4-nitrophenyl)-2-furyl]-2-propenamide is a biologically active derivative of furan with reactive centers of donor and acceptor type that is used as a starting material in the synthesis of drugs.

The structure of the substance was confirmed by NMR spectroscopy. The purity of the substance was determined using a system of high-efficiency liquid chromatograph Agilent 1100 HPLC.

Методом бомбової калориметрії експериментально визначено стандартну ентальпію згорання для 2-фурил-2-ціано-2-пропенаміда. На основі отриманих даних розраховано ентальпію утворення речовини в конденсованому стані. Ефузійним методом Кнудсена визначено температурну залежність тиску насиченої пари 2-фурил-2-ціано-2-пропенаміда за якою розраховано ентальпія сублімації. Проведено перерахунок ентальпії сублімації на 298К. Розраховано ентальпію утворення речовини в газоподібному стані за даними експериментальних досліджень та за адитивною схемою Бенсона.