Chemical reactive intermediates span an incredible range of temperatures and pressures, from internal combustion engines operating at temperatures upwards of 2000 K and tens of atmospheres of pressure to the near-vacuum of the interstellar media where temperatures can approach absolute zero. Many important reactive intermediates sit at intermediate conditions, such as emission products and atmospheric pollutants. Combustion and emission reaction rates are sensitive to both temperature and pressure in complex ways and most experimental techniques to measure these rates operate over a narrow parameter space. Theoretical kinetic modeling provides an opportunity to extend the measured reaction rates to unknown conditions, yet their ability to model reactions occurring at combustion temperatures is hampered by a lack of experimental data. In this talk, I will present my results applying theoretical kinetic modeling to recent experimental results of gas phase intermediates involved in soot production. In addition to the work on gas phase chemistry of soot production, results of solid phase chemistry will also be provided to get a complete picture in regard to soot production.