Is interstellar acetone produced by ion-molecule chemistry?

Abstract

The rate coefficient for the ion-molecule radiative association reaction CH 3 + + CH 3 CHO → (CH 3 ) 2 CHO + has been calculated in the range 10-300 K with the phase-space technique and the aid of a laboratory measurement of the analogous three-body association at room temperature. It has been suggested by Combes et al. that this reaction followed by dissociative recombination is responsible for the observed abundance of acetone (CH 3 COCH 3 ) in Sgr B2. However, it is shown here that the radiative association reaction is probably too slow even at 10 K to lead to the observed abundance of acetone in this source. The question of how acetone is produced in Sgr B2 is thus still unanswered.