Thermochemistry and Group Additivity Values for Fused Two-Ring Species and Radicals

Area of Science:

• Chemical kinetics
• Thermochemistry
• Computational chemistry

Background:

• Alkylomatic pyrolysis mechanisms are not well understood.
• Accurate thermochemical data is crucial for modeling chemical processes.

Purpose of the Study:

• To calculate the thermochemistry of fused two-ring aromatic molecules and radicals.
• To develop new group values for improved thermochemical estimations.

Main Methods:

• Utilized the CBS-QB3 level of theory for high-accuracy calculations.
• Defined and validated new group values against calculated data.

Main Results:

• Enthalpies of formation for some species differed by up to 13 kcal/mol from prior estimates.
• New group values achieved an average deviation of 0.4 kcal/mol, significantly improving accuracy.

Conclusions:

• The study provides crucial thermochemical data for fused aromatic systems.
• Developed group values represent a substantial advancement for predicting reaction energetics in alkylaromatic pyrolysis.