Aluminium monochloride, or chloridoaluminium is the metalhalide with the formula AlCl. Aluminium monochloride as a molecule is thermodynamically stable at high temperature and low pressure only.[2] This compound is produced as a step in the Alcan process to smelt aluminium from an aluminium-rich alloy.
Alcan process
When an aluminium alloy is placed in a reactor that is heated to 1,300°C and mixed with aluminium trichloride, a gas of aluminium monochloride is produced.[3]
2 Al(alloy) + AlCl3(gas) → 3 AlCl(gas)
It then disproportionates into aluminium melt and aluminium trichloride upon cooling to 900°C.
The process is an instance of the general sub-halide catalytic distillation method (subhalide process) developed by Philipp Gross.[4] It was sold to Alcan but never put into full-scale production.[5][6]
Interstellar medium
This molecule has been detected in the interstellar medium, where molecules are so dilute that intermolecular collisions are unimportant.[7]
↑Chase, M. W.; Curnutt, J. L.; Prophet, H.; McDonald, R. A.; Syverud, A. N. (1975-01-01). "JANAF thermochemical tables, 1975 supplement". Journal of Physical and Chemical Reference Data. 4 (1): 1–176. Bibcode:1975JPCRD...4....1C. doi:10.1063/1.555517. ISSN0047-2689.
↑Totten, George E.; MacKenzie, D. Scott (2003). Handbook of Aluminum. Vol.2: Alloy Production and Materials Manufacturing. CRC Press. p.59. ISBN0-8247-0896-2.
