of all these processes the Oxo reaction (equation 1) is the most important . the carbonylation of methanol with the rhodium iodide catalyst (equation 6) ranks second. it is a relatively new process, but it is expected that this process will dominate the manufacture of acetic acid in the future. the other processes are applied on a smaller scale in industry or are of only potential industrial importance . during the 1970s and early 1980s , when the crude oil prices were high, reactions such as the homologation of methanol and the glycol synthesis found considerable interest. it was thought that coal-based synthesis gas could replace oil as the major feedstock of the chemical industry. the rapid oil price decrease in the mid 1980s prevented these new syn- gas processes from going on stream.