Some of the process methods are give below to produce acetic acid in bulk
1.Oxidation of acetaldehyde:
Acetaldehyde can be oxidized by the oxygen in the air to produce acetic acid.
2 CH3CHO + O2 → 2 CH3COOH
2.Liquid phase oxidation of butane:
Liquified butane is combusted by air in use of various inorganic ions such as those to manganese, cobalt and chromium, peroxides type and then break down to generate acetic acid.
2C4H10 + 5 O2 → 4 CH3COOH + 2 H2O
3.Methanol Carbonylation:
In this process methanol CH3OH and carbon-monoxide CO, chemically react for the production of acetic acid according as per the equation
CH3OH + CO → CH3COOH
Acetic acid Process description by carbonylation of methanol in the presences of catalyst rhodium:
Process Flow sheet of Acetic acid
The process is carried out in a continuous stirred tank reactor. In this process methanol and CO are reacted in presence of Rhodium complex catalyst to give acetic acid. The liquid feed to the reactor consists of mixture of methanol feed stream used to scrub the effluent gas from the reactor. A recycle stream containing principally methyl acetate, methyl iodide and recycled catalyst are introduced at the top and CO is sparged from the bottom of the reactor. A small amount of methyl iodide and rhodium catalyst will be added to make-up any loss.
The reaction is exothermic and has a heat of reaction of 138 KJ/mol. The pressure in the reactor is 3Mpa and temperature is around 1900 C. the gaseous reactor effluent from the reactor is cooled to about 100C in a water cooled exchanger and condensed in a condenser. The liquid stream from the condenser goes to a high pressure separator to separate the un-reacted CO, CO2 and H2. The liquid from the high pressure separator goes to low pressure separator for separating the methyl iodide, methyl acetate from the gases and mixed with the gas effluent from the high pressure separator. These gases are scrubbed with Methanol to recover the methyl iodide and methyl acetate before leaves the system. The liquid from the scrubber is sent to reactor surge tank from where it goes to reactor.
The liquid from the reactor is removed and the pressure is let down and is introduced into the light ends distillation column. Here the lower boiling compounds are separated from the acetic acid and the other less volatile components such as catalyst. The lower boiling components consisting principally of methyl acetate and methyl iodide are recycled to the reactor.
The acetic acid, other higher boiling compounds and rhodium component are removed from the bottom of the column enters the catalyst recovery unit where catalyst is separated as bottom product and recycled to reactor. The top product contains acetic acid and water is sent to dehydration unit where water is separated from the acetic acid. The acetic acid from the dehydration unit consists small amount of propionic acid is sent to heavier ends distillation column for removing the propionic acid as bottom product. The top product contains acetic acid of 99% pure.