Making para-dibromobenzene [closed]








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What steps do I need to take to make the compound in the picture from just a benzene ring? Thank you.
[![enter image description here](https://i.stack.imgur.com/U5p29.png)](https://i.stack.imgur.com/U5p29.png)




According to US Patent 3062899A p-dibromobenzene is the major product of the bromination of benzene with 2 equivalents of bromine at ambient temperature. With catalytic aluminium trihalide this remains the outcome below 40C.


 3

According to this [forum](http://www.chemicalforums.com/index.php?topic=29556.0):



> 
> To benzene, (add) $\ce{Br2}$ and $\ce{HOAc}$ to get bromobenzene.
> Then (add) $\ce{ZnBr2}$ to get p-bromobenzene as the major isomer. Or
> from aniline, NBS and $\ce{HOAc}$ to get p-bromoaniline. Then
> diazotonization of aniline with $\ce{NaNO2}$ and subtitution with
> $\ce{NaBr}$ to get p-bromobenzene.
> 
> 
> 


As the source is a forum, I found it highly unreliable but then I found [a page](https://erowid.org/archive/rhodium/chemistry/bromobenzene.html) which shows the process of synthesis of bromobenzene. It says that the para isomer is formed as a minor by-product and there is also a note on the isolation and purification of the para isomer:



> 
> .....Now distill the crude bromobenzene slowly, rejecting the fraction
> boiling up to 150°C, and collecting that of bp 150-160°C. Yield,
> 28-29g (about 19ml). **A small quantity of crude p-dibromobenzene
> remains in the flask.**
> 
> 
> [....]
> 
> 
> The p-dibromobenzene formed as a by-product in the above reaction
> usually solidifies when the undistilled residue obtained in the first
> distillation is chilled. It may be isolated by adding about 10ml of
> methylated spirit and some activated charcoal to the flask, boiling
> for a few minutes, and filtering hot. On cooling the filtrate in
> ice-water, crystals of p-dibromobenzene, mp 89°C separate:
> recrystallise a second time if necessary to obtain colourless
> crystals.
> 
> 
> 


There is also [a patent](https://www.google.com/patents/US3062899)(@Waylander) which says that p-bromobenzene can be prepared by using bromine and aluminum trihalide as catalyst.



> 
> In general, the bromination of benzene with two moles of bromine per
> mole of benzene at ambient temperature produces predominantly
> p-dibromobenzene. If the bromination is conducted in the presence of
> an aluminun trihalide catalyst at low temperature, e.g., below about
> 40 C., the para-dibromo isomer is still the principal product.
> 
> 
> 


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