Theoretical and experimental study of the degradation of malonic acid diesters in gas phase

D. HENAO ARBOLEDA; F. MALANCA; W.J. PELÁEZ

PORTO

Simposio; Terceiro Simpósio Iberoamericano de Química Orgânica (SIBEAQO3); 2016

Terceiro Simpósio Iberoamericano de Química Orgânica (SIBEAQO3)-UNIVERSIDAD DE PORTO

Malonic acid diesters are widely used in the chemical industry as intermediates for the synthesis of a variety of organic chemicals and as the building blocks of different processes in which malonates are used as intermediates, such as pharmaceuticals, agrochemicals, vitamins, fragrances, and dyes. Until now, data atmospheric degradation of these compounds is not available in literature. To improve our knowledge of the atmospheric chemistry of malonic acid diesters, we report here the rate coefficients for the reaction between chlorine atom and a series of malonic acid diesters: di-methyl malonate (CH3OC(O)CH2C(O)OCH3, DMM), di-ethyl malonate (CH3CH2OC(O)CH2C(O)OCH2CH3, DEM), di-isopropyl malonate ((CH3)2CHOC(O)CH2C(O)OCH(CH3)2, DIPM), and di-tert-butyl malonate ((CH3)3COC(O)CH2C(O)OC(CH3)3, DTBM). Additionally, we present the determination of the fotooxidation mechanism of DMM and DTBM in absence and presence of NO2, supporting both by experimental and theoretical calculations.The rate constant for the reaction between malonic acid diesters and chlorine atom in gas phase were measured relative to cyclohexane, pentane and acetone. Photolyses were carried out in a photo-reactor using black lamps. Identification and quantification of reactants and products were performed by infrared spectroscopy. The rate coefficients measured for DEM, DIPM, and DTBM with chlorine atoms resulted to be approximately one order of magnitude higher than the corresponding for DMM (kDMM