Thermo-kinetic theoretical studies on pyrolysis of dimethoxymethane fuel additive

Many recent studies have been considered dimethoxymethane (DMM) as a potent fuel additive which reduces soot production and nitrogen oxides (NOx) emissions of diesel and biodiesel fuel. This study reports thermokinetic investigation of DMM pyrolysis in temperature range 300-2000 K using M06-2X and omega B97XD density functional methods and modest cost ab initio/complete basis set-quadratic Becke3 (CBS-QB3) procedure. The energy profile has been constructed using possible unimolecular H-atom transfer reactions (R1-R4) and simple bond fission reactions (R5-R11). Rate constant calculations were conducted at high-pressure (HP) limit and in the fall-off regimes using classical transition state (TST) and the statistical Rice-Ramsperger-Kassel-Marcus (RRKM) theories, respectively. Based on CBS-QB3 energies, branching ratios analysis reveals unimportance of all H-atom transfer reactions at T >= 400 K, while the homolytic bond cleavage reaction R5 which produces (CH3)-C-center dot and gauche-(OCH2OCH3)-O-center dot fragments is considered the main dominated decomposition channel with high competition from R6 ((CH3)-C-center dot and trans- CH3OCH2O center dot) and R7 (CH3O center dot and (CH2OCH3)-C-center dot) channels especially at elevated temperature.