08-22-03 01:24
No 454913
Is it acceptable to use toluene instead of benzene when benzene is called for in extracting product? For example, benzene is used to extract meth freebase after a synth, but would toluene also work?
(Chief Bee)
08-22-03 02:22
No 454922
(Rated as: excellent)
Always* use Toluene instead of Benzene when the latter is called for as a solvent in extractions, recrystallizations, azeotropic distillations etc. Benzene is very toxic (carcinogen), so never use it unless absolutely necessary - the only important property which differs from toluene is the boiling point, and only in few instances this difference will interfer, and it can most often be remedied by instead of refluxing the toluene, you simply heat it to 80°C with good stirring to emulate refluxing benzene.
Comparison of the Physical Properies of Benzene and Toluene
| Compound | Benzene | Toluene |
| CAS No. | 71-43-2 | 108-83-3 |
| Molecular weight | 78.1 | 92.13 |
| Boiling point | 80°C | 110.6°C |
| Melting point | +5.4°C | < -90°C |
| Density (20°) | 0.88 g/mL | 0.87 g/mL |
| Vapor pressure (20°C) | 100 mbar | 29 mbar |
| Refractive index nD20 | 1.5010 | 1.4969 |
| H2O Azeotrope | 8.9% H2O (bp 69.4°C) | 14% H2O (bp 84°C) |
* Naturally, you cannot substitute Benzene with Toluene in those instances when the Benzene is a reactant rather than a solvent, for example in the Friedel-Crafts alkylation with Allylbromide to give Allylbenzene, if you would use Toluene you would end up with a mixture of 4-Methyl-Allylbenzene and 2-Methyl-Allylbenzene, which are chemicals you probably don't have any use for.
(Hive Bee)
08-22-03 05:28
No 454950
Rhodium, your words fill me with wisdom, you trully are a gift to all the other little bumble bees that fly in and out of the hive.
Keep up your good work, you are inspiration to me and not to metion others.
your knowledge is undescribable
Without GLASSWARE where the fuck would we BEE?
(Stranger)
08-22-03 05:55
No 454957
I was just thinking that! I wonder if he lives on some far-away planet where super-humans who posess a much higher intellect live. Me, I live next to a McDonalds.
(Stranger)
08-22-03 23:39
No 455075
isn't toluene a bit polar? Or doesn't this matter?
(Active Asperger Archivist)
08-23-03 00:03
No 455078
Polarity is relative.
In this particular case, toluene is very non-polar. When compared to something like benzene, sure it's going to be polar. However, the difference is neglible in 99%+ of the cases in which you will deal with these chemicals. Especially for the chemistry involved here. By the time you've learned enough about chemistry to be involved in reactions the it makes a difference, you won't need to ask why, how, and other related questions.
Act quickly or not at all.