THE HYDROXYL RADICAL REACTION-RATE CONSTANT AND PRODUCTS OF ETHYL 3-ETHOXYPROPIONATE

The relative rate technique has been used to measure the hydroxyl radi cal (OH) reaction rate constant of ethyl 3-ethoxypropionate (EEP, CH3C H2-O-CH2CH2C(O)O-CH2CH3). EEP reacts with OH with a bimolecular rate c onstant of (22.9 +/- 7.4) X 10(-12) cm(3) molecule(-1)s(-1) at 297 +/- 3 K and 1 atmosphere total pressure. In order to more clearly define EEP's atmospheric reaction mechanism, an investigation into the OH + E EP reaction products was also conducted. The OH + EEP reaction product s and yields observed were: ethyl glyoxate (EG, 25 +/- 1% HC(=O)C(=O)- O-CH2CH3), ethyl (2-formyl) acetate (EFA, 4.8 +/- 0.2%, HC(=O)-CH2-C(= O)-O-CH2CH3), ethyl (3-formyloxy) propionate (EFP, 30 +/- 1%, HC(=O)-O -CH2CH2-C(=O)-O-CH2CH3), ethyl formate (EF, 37 +/- 1%, HC(=O)O-CH,CH,) , and acetaldehyde (4.9 +/- 0.2%, KC(=O)CH3). Neither the EEP's OH rat e constant nor the OH/EEP reaction products have been previously repor ted. The products' formation pathways are discussed in light of curren t understanding of oxygenated hydrocarbon atmospheric chemistry. (C) 1 997 John Wiley & Sons, Inc.