DETAILED MODELING OF THE PYROLYSIS OF TRICHLOROETHENE - FORMATION OF CHLORINATED AROMATIC SPECIES

Comprehensive product yield determinations from the high-temperature, gas-phase pyrolysis of trichloroethene (C2HCl2) using two fused silica tubular how reactors coupled to in-line gas chromatographic-mass spec trometric analyses are reported. Initial decomposition was observed at 1000 K with formation of HCl and C2Cl2. Pronounced molecular growth w as observed at higher temperatures as evidenced by the formation of C2 Cl4, C4Cl4, and C6Cl6 (cy) as major (greater than or equal to 5 mole % ) products and C4Cl2, C4Cl6, C6HCl5 (cy), C8Cl6 (cy), C8Cl8 (cy), C10C l8 (cy), and C12Cl8 (cy) as minor (less than or equal to 5 mole %) pro ducts. The effects of reactor surface area to volume (S/V) ratio were evaluated by conducting detailed product analyses with 0.1 cm i.d. and 1.0 cm i.d. reactors. Under the higher S/V ratio, C2HCl3 decompositio n was increased by an order of magnitude and product distributions sug gested that radical-radical and radical-atom recombination rates were enhanced. Product yields under reduced S/V ratio indicated that yields of perchlorinated aromatic and perchlorinated PAH species were a fact or of 10 larger than observed for higher S/V ratios. A detailed reacti on mechanism is presented for the 1 cm i.d. reactor data describing mo lecular growth up to the formation of C8Cl6 (cy) and C8Cl8 (cy). Compa rison of predicted versus experimental major and minor species profile s are presented, with generally good agreement. Important radical-mole cule addition reactions leading to molecular growth are identified usi ng sensitivity analysis and production rate calculations.