Study of combustion intermediates in fuel‐rich methyl methacrylate flame with tunable synchrotron vacuum ultraviolet photoionization mass spectrometry

Abstract

A fuel-rich premixed laminar methyl methacrylate (MMA)/O 2 /Ar flame at low pressure (30 Torr) with the equivalence ratio (f) of 1.60 is studied in this work. Synchrotron vacuum ultraviolet photoionization combined with molecular beam mass spectrometry is employed to identify the combustion intermediates including isomeric intermediates. The observed combustion intermediates can be classified as four types: radicals, non-cyclic hydrocarbons, cyclic hydrocarbons and oxygenates. Benzene is the unique aromatic hydrocarbon detected in this work, and several oxygenates with two oxygen atoms are identified. Mole fraction profiles of most intermediates are evaluated, which can help understand the MMA combustion mechanism under fuel-rich conditions. The similarities among rich flames of MMA and other oxygenated fuels, as well as the characteristics of rich MMA flame, are also discussed. The results show that combustion of MMA not only reduces soot emissions, but also has low concentrations of some potential toxic by-products.

Helium Nanodroplet Isolation of the Cyclobutyl, 1-Methylallyl, and Allylcarbinyl Radicals: Infrared Spectroscopy and Ab Initio Computations

“…Hydrocarbon radicals are prevalent in combustion environments, namely, those that originate from organic flames , or pyrolysis of organic solvents. , The reaction between CH and propene (C 3 H 6 ) occurs in Titan’s atmosphere and other methane containing gas clouds, in which CH is produced from methane photolysis . The CH + C 3 H 6 reaction produces 1,3-butadiene, which is a precursor to the formation of benzene and polycyclic aromatic hydrocarbons.…”

Threshold Photoelectron Spectra of Combustion Relevant C4H5 and C4H7 Isomers

“…C 4 H 5 and C 4 H 7 , on which we focus in this study, play a dominant role in the pyrolysis of methyl tert -butyl ether, in the unimolecular decomposition of dimethylfuran, in the combustion of methyl methacrylate flames, in fuel-rich flames , and biodiesel. , The latter contains, e.g., fatty acid esters, compounds with double bonds that preferentially lose H atoms in the α-position to the CC double bonds, forming intermediates that can be described as alkylated allyl radicals. The smallest alkylated allyl radicals are the methylallyl isomers.…”

Vibrational Bands of the 2-Butyn-1-yl Radical

“…8 C 4 H 5 radicals are also involved in the unimolecular decomposition of 2,5-dimethylfuran, the pyrolysis of methyl tert-butyl ether, 7 and the combustion of fuel-rich flames and biodiesels 18 and methyl methacrylate. 27 While there is strong evidence for the occurrence of 2-butyn-1-yl in many crossed-beam studies and flame experiments, there is no recorded vibrational spectrum of the radical. The goal of the current study was to isolate and measure the vibrational frequencies of the 2-butyn-1-yl radical.…”

“…Their Franck–Condon analysis based on calculated frequencies suggested that the C 4 H 5 radicals observed in the experiments included 2-butyn-1-yl and/or 1-butyn-3-yl, as well as i -C 4 H 5 (CH 2 CHCCH 2 ) . C 4 H 5 radicals are also involved in the unimolecular decomposition of 2,5-dimethylfuran, the pyrolysis of methyl tert -butyl ether, and the combustion of fuel-rich flames and biodiesels and methyl methacrylate …”