Acetic acid process

A method for the production of acetic acid comprising:

• (A) reacting,
• (i) methanol,
• (ii) carbon monoxide, and
• (iii) water,
• in a carbonylation reactor in the presence of a carbonylation catalyst to produce a reactor mixture;
• (B) measuring a first value for a reference component selected from the group consisting of glacial acetic acid (GAA), a pentavalent phosphine oxide, triphenyl phosphine oxide (TPPO), a catalyst promoter, a catalyst stabilizer, water, acetic acid, hydrogen iodide, methyl iodide, methyl acetate, acetaldehyde and carbon monoxide by Raman spectroscopic analysis with an uncoated probe or flow-through cell in contact with the reactor mixture;
• (C) measuring a second value for the reference component and measuring the concentration of one or more components of interest selected from the group consisting of glacial acetic acid (GAA), a pentavalent phosphine oxide, a catalyst promoter, a catalyst stabilizer, water, acetic acid, hydrogen iodide, methyl iodide, methyl acetate, acetaldehyde and carbon monoxide in the reactor mixture by Raman spectroscopic analysis;
• (D) determining an Adjustment Ratio by dividing the first value for the reference component by the second value for the reference component;
• (E) calculating an Adjusted Value for the concentration of the component(s) of interest by multiplying the concentration of the component(s) of interest by the Adjustment Ratio;
• and
• (F) modifying at least one process condition in the carbonylation reactor or a separation unit selected from the group consisting of temperature, pressure, component of interest concentration, feed stream flow rate and exit stream flow rate;
• wherein the Adjustment Ratio is maintained at a value of 0.01-5.