Chemical stabilized over Botha-Spalding burner at atmospheric pressure.

Chemical speciation of a laminar premixed stoichiometric ame of MMA atatmospheric pressure was studied in Novosibirsk (Russia) using ame samplingmolecular beam mass spectrometry (MBMS) with soft electron impactionization. Thorough descriptions of the setup and experimental procedureare given in 11, and we provide only essential details here. A at premixedame was stabilized over Botha-Spalding burner at atmospheric pressure. Theburner consisted of a perforated (0.5 mm diameter ori ces with 0.7 mm centerto-center spacing) brass disc 16 mm in diameter and 3 mm thick, embedded ina brass housing. Internal volume of the burner was lled with small stainlesssteel balls for gas ow alignment. The temperature of the burner was kept at90C using thermostated water circulating through the channel in the burnerhousing.Bottom part of the burner was connected with a system supplying burnerwith a fresh gaseous mixture. The burner, vaporizer and the fuel supplyingsystem are shown in Fig. 1. Liquid methyl methacrylate (MMA) was suppliedto the vaporizer via a stainless steel capillary using a syringe driven by astepper motor. The vaporizer was a Pyrex vessel lled with small steel ballsand equipped with an electric heater wrapped around the walls of the vessel.The temperature of the vaporizer was maintained at 90C. This temperaturewas high enough to vaporize completely the liquid fuel, supplied continuouslyto the vaporizer, but at the same, it did not exceed the boiling temperatureof MMA (which is 100C) to prevent boiling of the liquid in the capillary(that could cause instabilities in the fuel vapor supply to the burner). The linebetween the burner and the vaporizer was maintained at 100C by an electricalheater. The temperatures of the line and the vaporizer were controlled by4T-type thermocouples. In the vaporizer, MMA vapors were mixed with argon.The line between the vaporizer and the burner had an inlet for oxygen supply.The ows of argon and oxygen were regulated by the calibrated mass-ow controllersMKS Instruments Inc. No MMA polymerization was observed duringexperiments.