  Complex organic molecules (COMs) have been detected in the gas-phase in cold
and lightless molecular cores. Recent solid-state laboratory experiments have
provided strong evidence that COMs can be formed on icy grains through
'non-energetic' processes. In this contribution, we show that propanal and
1-propanol can be formed in this way at the low temperature of 10 K. Propanal
has already been detected in space. 1-propanol is an astrobiologically relevant
molecule, as it is a primary alcohol, and has not been astronomically detected.
Propanal is the major product formed in the C2H2 + CO + H experiment, and
1-propanol is detected in the subsequent propanal + H experiment. The results
are published in Qasim et al. (2019c). ALMA observations towards IRAS
16293-2422B are discussed and provide a 1-propanol:propanal upper limit of <
0.35 - 0.55, which are complemented by computationally-derived activation
barriers in addition to the performed laboratory experiments.
