[democanarchis]

Hey all, need to do a reaction in benzene as toluene isn't working as a replacement, and having never handled it on a largeish scale (~250mL) had a question about disposal. Our solvent wastes are just open containers on the bench area, so I obviously am cautious about putting a relatively volatile carcinogen in them. Is it ok to just dilute it up in toluene, or what is the standard disposal procedure?

[discodermolide]

Hey all, need to do a reaction in benzene as toluene isn't working as a replacement, and having never handled it on a largeish scale (~250mL) had a question about disposal. Our solvent wastes are just open containers on the bench area, so I obviously am cautious about putting a relatively volatile carcinogen in them. Is it ok to just dilute it up in toluene, or what is the standard disposal procedure?

You can dilute it, but I would put it in a suitable container, seal it and get it incinerated.
I find it hard to believe that the reaction does not work in toluene, which reaction is it?

[democanarchis]

Chlorination of a quinazolinone as per dx.doi.org/10.1021/jo049195+ with POCl3 and diethylaniline in benzene. Attempted the same procedure in refluxing toluene, and a large amount of side product seems present. Tried another literature procedure using toluene/DIPEA at 80 degrees and didn't get any reaction

[OC pro]

on a largeish scale (~250mL)

Don´t panic because of using 250ml benzene. The carcinogenic effect comes from long-term exposure (several years). Just dispose it like all other non-halogenated solvents.
The reaction should run definitely also in toluene (not reflux, only 80 to 90°C) (like discodermolide also mentioned).
Was the toluene at least distilled ( means free of additives) or simply out of the can?
What is the side product?
We had problems in chlorination using POCl3 in chloroform containing 1-2% of EtOH. This gave us the product with OEt substituent instead of chlorine.

[Doc Oc]

The boiling points of benzene and toluene are extremely different (80 deg vs 110 deg), that very likely played a role in the reaction mixture you saw.  Do what OC Pro suggested and run it in toluene at 80 degrees or try another solvent that is closer to the same boiling point (I used cyclohexane successfully as a replacement in the past).

[movies]

Toluene is more reactive in electrophilic aromatic substitution, so that could be the origin of your side product as well.  I have use nitrobenezene for EAS reactions before with good results, but if toxicity is your concern, then this is not a good solution for you.  Benzene is indeed toxic, and if you can smell it then you are above the allowable OSHA exposure limit, so you really should handle it in a hood and then put it in a closed waste container after the reaction to minimize your exposure.  Personally I think benzene has gotten a lot more bad press for its toxicity than other comparably toxic materials, so I wouldn't fret about it too much and just use "normal" safe handling procedures.