Phthalic Acid and Fatty Alcohols from Vinyl Gloves: Part 3

[RavenFly1232]

I was making my own phthalic acid, and so far so good, but when it came to making phthalic anhydride, a couldn't make it. The stuff i made looked a lot like yours, and I recrystallized phthalic acid three times, so it should be pretty pure, but it simply won't melt, or sublimate. I used sulfuric acid to convert potassium phthalate to acid, and the stuff I made will melt and boil, when S. Acid is present, but still I wont get any fluffy crystals (like in nurdrages video).

[UC235]

@RavenFly1232 You really need to crank the heat to get it to sublime. The decomposition temperature is ~190C . Sulfuric acid shouldn't be present when trying to dehydrate it. The pure crystalline solid should be heated in a covered beaker until it melts and further heated until it "boils (water coming from dehydration)" and starts subliming onto the upper flask walls.

[ooberc]

I would had love too have seen the process of how you went about figuring out what your fatty alcohol's turned out to be.

[lexichronicle2]

No, thank you for the interesting video!

I have a suspicion your fatty alcohol will contain more than one or isomers of one, which would explain the none constant BP you saw on the still, as close boiling isomers tend to be tricky to separate by distillation.

It would also likely be better to remove traces of water from the organic layer using something like MgSO4, K2CO3 or CaSO4 rather and NaOH I'm thinking. But could be derping.

[UC235]

@lexichronicle2 The problem with the organic layer here is that it's viscous. NaOH was a poor choice, as is obvious. NaOH is effective for drying lower alcohols however, but requires distillation afterward. The azeotropic drying with isopropanol seemed to work well here. I discarded the initial short choppy fraction of product that came over but the main fraction's boiling point slowly and smoothly rose. I agree that it is probably mixed isomers, however.

[hkparker]

I really enjoy watching your mechanisms, I learn a lot, and I think its convincing me to focus on organic chem in college...

[thecrazychemist]

Might be worth mentioning that the ester hydrolysis proceeds via the BAc2 mechanism (i.e. Base catalysed bimolecular acyl-oxygen cleavage). Also of note is that a dianionic species is postulated in the Canizzaro reaction. Good videos, I look forward to seeing more. Your experimental technique is pretty good, only quarms are a few minor things, such as use of the sep funnel (top layer should be poured out the top, not drained through the tap).

[UC235]

@thecrazychemist

I always thought the Canizzaro reaction had a neat mechanism. Much like the skraup, I think I'll have to run one just because. (No video on the skraup, but I used catalytic iodine per C. O'Murcho, Synthesis, 1989, 880-882. (the paper mentioned on curly arrow) and it went very smoothly).

As for the sep funnel, they sure didn't tell us that in undergrad lab. I can see why now that I think about it, though a drop or two of the other phase means roughly diddle in this case.

[PauldChemist]

Awesome videos =) All 3 of them.

Thank you so much for sharing =)