[SirRoderick]

So basically I am looking for some information on a production process for aniline, starting from benzene. This is based on a flow chart that we were given and the assignment is to provide an explanation for every step. I was hoping someone might know a bit about the process and can provide me with some information that is surprisingly difficult to find on the internet. Especially considering this provided chart seems out of date (for instance they use iron turnings and HCl for the reduction, which I know is not very efficient).

So what I've got ATM is the following:

First there's a nitrification of benzene with a sulphuric/nitric acid mix, easy enough. From there the chart goes into a "separator", which I assumed separates the nitrobenzene from the acids. One part flow back to an acid recovery, so that makes sense, but the other branch does something odd.

It splits into two other branches. One goes into a reducer, with iron turnings and HCl, that is a Bechamp reduction I believe, fair enough. Now the other one goes into a "wash water" module, which is something that sounds like it should happen in the seperator right? From that washer it goes into a still with steam, which leads to "pure" nitrobenzene and it stops there.

I am confused why there seems to be an additional purification here. Are they shipping nitrobenzene/acid mix into the reducer? What sort of apparatus is this "still"? Is it a destillation? Why is steam mentioned?

Right well, the "crude" nitrobenzene after the separator (that does NOT get a wash for some reason) goes into the reducer. It there reacts into aniline. Can anyone tell me what sort of conditions this would demand? Temperature and pressure?

After the reduction it appears to be separated into "sludge", "aniline water" and "crude aniline". Any information on what these actually contain would be very welcome, what impurities in the "crude" especially. The aniline water is fed back into the reducer, so I doubt it's just aniline in water. The crude aniline is fed into a still, again with steam, and results in pure aniline. What sort of purification is this, a simple destillation? Reaction conditions?

Any information you can provide me, even if I didn't ask for it specifically, will be very appreciated.

[Wastrel]

Iron is used because it's cheap.  There is an extra purification step for nitrobenzene that is going to be sold instead of converted to aniline.

A quick skim through "Aniline and it's derivatives" by Groggins provides a few more bits of information, at least for early 20th century plants.  The iron is in slight excess.  The amount of acid (or ferrous chloride which can be recycled) used is much less than stoichiometric.  The sludge is primarily ferric oxide.  The aniline water can be 3 to 5% aniline.  It doesn't mention the impurities in crude aniline.  You might be better consulting a modern encyclopedia of chemical technology.

See Steam distillation. 

[SirRoderick]

Thank you for the information 

And I am trying to find a decent book on this in the library.