Sciencemadness Discussion Board

Acetylene trimerization to Benzene

Vaylo - 29-10-2002 at 23:37

Hey all,

In the Phenol thread, PrimoPyro mentioned a technique for the timerization of acetylene to benzene using a CuCN catalyst. I was just wondering if anyone could suply some further information on the reaction; conditions equipment etc (should the reaction take place in a bomb under pressure or would a simpler setup work?) or, ideally, a reference for the procedure.




PrimoPyro - 30-10-2002 at 04:53

The procedure is valid, but I stated the wrong catalyst. It is Zn(CN)2 not CuCN, sorry. Where I got CuCN from is beyond me.

The ref I have is in March's Advanced Organic Chemistry, 5th Ed. and it states that Zn(CN)2 initiates trimerization of acetylene to benzene at atmospheric pressure.

I can quote the ref after some sleep. :)


Marvin - 31-10-2002 at 09:36

Possibly becuase copper metal is also supposed to catalysed the process, get the temperature wrong and you end up with a porous black polymer.

Its only supposed to convert very slowly, I dont know if it could constitute a usful method of making benzene.

Given acetylene is sold as a gas dissolved in acetone, and its explosive nature, I think this is probably as uneconomical as it is unsafe.

vulture - 7-11-2002 at 05:56

If you use Ni(CN)2 as a catalyst, you'll end up with cyclooctatetraene, the 8 carbon homologe of benzene, formula: C8H8.

I have no idea about reaction conditions though.