Patent ID: 8629298

Claim:
A method for measuring a component of a separations unit downstream from the acetic acid reactor comprising: (i) directing a feed stream to a separations unit, wherein the feed stream comprises the following components: methyl iodide, water, methanol, methyl acetate, acetaldehyde, acetic acid, alkanes and propionic acid, (ii) separating the feed stream in the separating unit into an overhead exit stream and a bottoms exit stream wherein the overhead exit stream comprises the following components: 30 wt. % to about 70 wt. % methyl iodide, 10 wt. % to about 40 wt. % water, 5 wt. % to about 15 wt. % methyl acetate, less than 2 wt. % acetaldehyde, 5 wt. % to about 35 wt. % acetic acid, 1 wt. % to about 10 wt. % alkanes and wherein the bottoms exit stream comprises the following components: 80 wt. % to 100 wt. % acetic acid, 3 wt. % to about 20 wt. % water; and measuring a characteristic of one or more said components in said separations unit by Raman spectroscopic analysis.