Example of the variation in CH₃OH with time for L_* = 10⁰ L_⊙ (left) and L_* = 10⁵ L_⊙ (right). Lines are for the 100 parcels (full grid) from the center, color-coded by the temperature at t = 10⁶ yr. The abundance of CH₃OH decreases sharply at late times because of the reaction with neutral and ion species. For instance, at t = 5 × 10⁵ yr, the most important destruction reactions are H₃O⁺ + CH₃OH → CH₃OH₂⁺ + H₂O and H₃⁺ + CH₃OH → CH₃⁺ + H₂O + H₂.