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Author: Subject: Oxidizing Naphthalene to Phthalic anhydride
smuv
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[*] posted on 2-11-2011 at 21:12


Probably using a larger excess of base will avoid this side product. You can imagine, that under harsh enough conditions, hydroxide would add into the a-ketoester, to form the deprotonated acetal. The deprotanated acetal could then go on to add into KMnO4. A mechanism like this is only favored in strongly basic conditions (notice the orgyn procedure is not using much base, balance the equation and you will see).

Additionally acidic conditions would totally avoid this product, but it is also more likely that you will get cleavage of you phthalic acid product under these conditions.

One thing that comes to mind, is it may be possible to produce phthalic anhydride from xylenes (mixed isomers) by oxidizing the xylene, and sublimating the product. I assume that the phthalic anhydride formed has a much higher vapor pressure than either iso or terephthalic acid. This difference in vapor pressures may provide a means of isolating only phthalic anhydride from this mixture.




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[*] posted on 2-11-2011 at 23:20


Quote: Originally posted by smuv  

...it may be possible to produce phthalic anhydride from xylenes (mixed isomers) by oxidizing the xylene, and sublimating the product...


Would this be achieved like the oxidation of toluene to benzoic acid and MnO2? Xylene and KMnO4 combined and refluxed together and then filtered with drying then sublimate it out?

Would you have any ideas for a decent but not too exotic phase transfer catalyst for these reactions? I thought maybe a little bit of detergent or cascade or something but I figured something better must exist.




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[*] posted on 3-11-2011 at 08:55


I said in a previous post about a a stoichiometry calculator but hadn't found a crack or patch for it, well i think i have cracked it... on this website below alot of shizz there is a button saying Get Crack, click on it, will start downloading a rar. and just extract to desktop or where ever you want it, im 90% sure its the full version, looks like it to me because i could never be able to save data on it :) great tool for amateurs like me :)

http://cracks.bz/download_EBAS.1.0.1.63.cracked-SND_crack_se...




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[*] posted on 3-11-2011 at 09:04


Dude that site looks like a virus hotbed.



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[*] posted on 3-11-2011 at 09:59


i checked it out and its fine, no viruses found, u dont have to do it, just a site i found with a crack that works, its VERY hard to find a patch for a program that isnt that popular compared to other software i have tried to crack



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[*] posted on 3-11-2011 at 10:15


There is no need to crack anything. EniG. Chemistry Assistant is a calculator that can parse empirical formulas and treat them as MW. It is a freeware and very good with an easy interface. It also has a gadget to calculate the amounts required for preparing solutions of many inorganic and a few organic reagents with the density tables integrated.



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[*] posted on 3-11-2011 at 10:18


Thanks, I'll check that out when it's morning time :)



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[*] posted on 4-11-2011 at 07:46


http://www.sciencemadness.org/talk/viewthread.php?tid=6573

"...phthalic anhydride from naphthalene"
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[*] posted on 15-11-2011 at 01:54


Ok so i was ment to get some glassware from Panchie but he still hasn't u2u'd me to say hes posted it, so i was wondering, could i use stainless steel pot with lid to boil the Naphthalene with eh Potassium Permanganate? or would the stainless steel do something to the reaction?



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[*] posted on 16-11-2011 at 10:21


Given you provide no reference, I can only guess you are talking about the synthesis of phthalaldehydic acid as described in Org. Synth.?
Quote: Originally posted by Chemistry Alchemist  
Ok so i was ment to get some glassware from Panchie but he still hasn't u2u'd me to say hes posted it, so i was wondering, could i use stainless steel pot with lid to boil the Naphthalene with eh Potassium Permanganate? or would the stainless steel do something to the reaction?

Neglecting the obvious problem of oxidative corrosion, how the hell are you going to reflux in a pot with a lid? (And why would you want to do that!?)
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[*] posted on 16-11-2011 at 17:30


Dude, I'm just asking a simple question which needs a yes or no explination... What's going to be so corrosive in the reaction? I just really want to do this reaction!



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[*] posted on 16-11-2011 at 18:45


Nicodem is actually being very nice to you, though it may seem back handed.

I think his answer would best be paraphrased as; No.


If you can not reflux the pot then the question of corrosion is largely superfluous. The lid is not going to work as a reflux.


Google offers this, and many other tantalizing titbits;
"In neutral and alkaline solutions, sodium permanganate is not corrosive to iron, mild steel or stainless steel. However, chloride corrosion of metals may be accelerated when an oxidant such as F2PP-98 Potassium Permanganate is present in solution. Plastics such as polypropylene, polyvinyl chloride Type I (PVC I), epoxy resins, fiberglass reinforced plastic (FRP) and TFE, and Tefzel EFTE are best. Refer to Material Compatibility Chart."

http://www.hepure.com/potassium-permanganate.html

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[*] posted on 16-11-2011 at 21:38


Sorry if I took it the wrong way, I was really just looking for a yes or no answer anyway :)



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