Paracetamol Analysis

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All manufacture of paracetamol follows PNCB process route. Manufacturers of paracetamol in India use PNCB route and iron / hydrogen reduction to obtain Para amino phenol (PAP), an intermediate for paracetamol. Chlorobenzene with hydrolysis is carried out by the reaction of 9% caustic soda solution with pnitrochlorobenzene. The reaction mass is filtered and with appropriate process control and proper design of the reactor, the yields are optimized, leading into lower requirement of inputs and production of lower quantities of effluent. The sodium salt of p-nitrophenol is treated with concentrated sulphuric acid at 35-45°C. p-Nitrophenol is filtered. With proper filtration and water wash, alkaline liquor trapped into sodium salt of p-nitrophenol…show more content…
After cooling process, filtration of crude paracetamol takes place. The pure paracetamol is treated with charcoal and pure paracetamol is then recrystallized in water. The wet cake of paracetamol is centrifuged, dried and packed. The temperature adjustment during acetylation makes sure complete acetylation of p-aminophenol and reduction of formation of side-products. The filtrate, after filtration of crude paracetamol, is dilute acetic acid solution which contains unreacted p-aminophenol and paracetamol. Secondary acetylation ensures that the conversion of p-aminophenol is accomplished. With solvent extraction, paracetamol undergoes recovery and dilute acetic acid could find some uses. The filtrate obtained after filtration of pure paracetamol is reused in the purification step 3-4 times before being removed as effluent. It is recovered from this effluent by decreasing the temperature or by solvent extraction or by salting out. This is able to improve the…show more content…
These controllers make sure the operating condition (pressure and level controllers) of the column and eliminate the disturbance (flow rate controllers) of the ambient. The controller output variables are the position of valves and process variables are the mass rates and pressure. The fluctuation of the feed mass flow is compensated by FC1 controller. The fluctuation of cooling water and heating steam is eliminated by the PC and the FC3 controllers. The level controllers (LC1 and LC2) make sure operation works properly because the reflux and flow rate will approach to zero if liquid was not present in the reflux drum and the bottom of the column. So, PI controller is applied here. The separation is based on the sustenance of the temperature difference between the head and bottom products. On the middle level of control hierarchy, the process variables are two tray temperatures which characterize the upper (rectifying zone) and lower (stripping zone) part of the column. The controlled tray temperature is chosen based on the steady state characteristic. By manipulating the set point of FC2 controller, the temperature of the upper column part is controlled, whereas the temperature of the lower column part is manipulated by the set point of FC3 controller. The purities of the products indicate the quality of the separation. Hence, the purity of the products is manipulated on the top level of the control hierarchy.

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