Sciencemadness Discussion Board - Terephthalic acid from PET

Terephthalic acid from PET

chromium - 12-12-2005 at 16:51

Terephthalic acid can be made by saponification of polyethylene terephthalate (PET). Polyethylene terephthalate is common polyester, readily available as plastic from drink bottles.

Saponification usually takes place if ester is heated with hydroxides. For example we could take NaOH solution in water and heat PET pieces in it. This however is less practical as takes hours or days to complete and product is harder to separate. It was possible to saponify thin pieces of PET at room temperature with month or less if solution of small amount of NaOH in 75% methanol was used. Saponification is trully fast if NaOH is dissolved in ethylene glycol and this solution is heated nearly to its boiling point (195...200C). Description of very similar process is given in [1].

C6H4(COOCH2)2 + 2NaOH = C6H4(COONa)2 + (CH2OH)2
192x + 80x = 210x + 62x

Reagents:
Ethylene glycol 55ml
NaOH 12.0g
PET 22.0g
sulfuric acid 5 mol/l solution 30ml

NaOH was taken with some excess over theoretical amount. Ethylene glycol is just solvent and does not take part in reaction. 55ml seemed fair amount for this reaction.

Mixture of ethylene glycol, PET and NaOH was well stirred in stainless steel beaker. Beaker was placed onto hotplate and heating applyed.

Hotplate was switched off as soon as mixture started to boil and was switched on again when boiling ceased. Boiling point of this mixture was near to 200C. Mixture was continuously stirred with steel rod. This process lasted 20 minutes. During this liquid turned milk-white and pieces of plastic gradually decomposed.

Beaker was removed from hotplate. After some cooling 200ml water was added and mixture was well stirred. More water was added and stirring was continued to dissolve all solid substance. Even though there were some white pieces that had inital shape of plastic parts it all dissolved. Almost 400ml water was needed for this. Solution was filtered with coffee filter.

5 mol/l sulfuric acid was added dropwise to filtered solution. White precipitate at once appeared. Ph was checked and no more sulfuric acid was added when ph 2 was reached. Adding of sulfuric acid must be done in well ventilated area as some dioxane may be involved. Testing of ph is not strictly necessary as amount of sulfuric acid can be easily computed. One needs 0.5 mole of sulfuric acid for each mole of NaOH initially taken. Mixture was well stirred and left to stand for 30 minutes.

White precipitate was separated at first by filtration. It still contained a lot of liquid that was impossible to remove this way. Impure and wet terephthalic acid was placed together with filter paper onto piece of strong cotton fabric. This fabric was folded as bag and pressed hard until no more water separated. This crude terphtalic acid was mixed again with 500ml water and separated by filtration and pressing to get still purer product.

Yield of terephthalic acid is almost theoretical. Ethylene glycol can be concentrated from aqueous solution by boiling and used repeatedly. Concentrating must be done in fume hood as some dioxane may be formed because of sulfuric acid.

Terephthalic acid is almost insoluble in water. When clean it is odorless. It is not deliquescent but somewhat hygroscopic. Heating is needed to dry it completely and remove last traces of organic solvents.

References:

1. A. Oku *, L.-C. Hu, E. Yamada, "Alkali decomposition of poly(ethylene terephthalate) with sodium hydroxide in nonaqueous ethylene glycol: A study on recycling of terephthalic acid and ethylene glycol", J. Appl. Polym. Sci. 1997,. 63, 595

[Edited on 13-12-2005 by chromium]

[Edited on 13-12-2005 by chromium]

[Edited on 13-12-2005 by chromium]

All_2.JPG - 203kB

Polverone - 12-12-2005 at 23:22

Interesting, Chromium. I will turn this into a PDF. It is possible to do the same in a strong aqueous solution, though. With enough NaOH the temperature can be raised well above 100 C without boiling. Overnight heating seems sufficient to decompose plastic this way. I noticed the same phenomenon where the plastic stays in chunks even though it turns white and dissolves easily when more solvent is added.

chromium - 13-12-2005 at 00:27

I did this once in aqueous solution but problrem was that PET started to decompose with reasonable rate if near-boiling NaOH solution was almost concentrated. Lot of NaOH is needed for this and such solution corrodes even stainless steel, although verry slowly. I had no idea how to separate sodium terephthalate or terephthalic acid from concentrated NaOH solution without reacting lot of NaOH with acid. So i looked for better way.

[Edited on 13-12-2005 by chromium]

bio2 - 13-12-2005 at 12:00

.....in aqueous solution but problrem was that PET started to decompose .........

Were you able to identify the decomposition products? or
Venture a quess perhaps?

Seems that benzoic acid as from pyrolysis of PET would be formed also here to some extent if decomposed.

chromium - 13-12-2005 at 12:13

Quote:

Originally posted by bio2
.....in aqueous solution but problrem was that PET started to decompose .........

Were you able to identify the decomposition products? or
Venture a quess perhaps?

Seems that benzoic acid as from pyrolysis of PET would be formed also here to some extent if decomposed.

No-no this decomp was just saponification as with ethylene glycol.

12AX7 - 13-12-2005 at 15:20

FYI, the industrial deesterification process involves high-temperature water or ethylene glycol in an autoclave. I forget typical processing times.

Tim

bio2 - 13-12-2005 at 16:00

Here is an interesting article on the subject.

http://www.mhi.co.jp/tech/pdf/e401ex/e395254.pdf

Polverone - 14-12-2005 at 14:48

I have made a PDF version of your article. It can be found at http://www.sciencemadness.org/member_publications/terephthal.... Once it has been looked over it will be added to the article index like the others were. I made a small addition to the article: I included a picture of the recycling symbol that indicates an article is made of PET. I do not know if this symbol is used worldwide or just in the US. If non-US members inform me that it is unfamiliar, I will add a note that it is not an international symbol.

ordenblitz - 14-12-2005 at 16:32

I was wondering why a mad scientist would want terephthalic acid.
It doesn't seem all that useful to me.
Would it be terribly interesting to make polyester at home? Certainly the aim is not PET if that is the starting material.

What are some of the mad uses for it in the amateur world?

Alembic - 15-12-2005 at 05:51

Well, I can think of two uses for TPA.

1. Potassium hydrogen terephthalate makes very nice pyrotechnic whistles (with KP oxidizer) and has the advantage of being just about completely non-hygroscopic.

2. If you can decarboxylate benzoic acid to benzene, you should be able to do the same with TPA. It will of course require twice as much alkali.

From my notebook

Quantum - 14-4-2006 at 17:27

Three 500mL PET bottles were cut up into ~1cm.sq bits and massed to 22.0grams. The greenish(dyed) impure ethylene glycol was placed in a 250mL flask and heated with mag. stirring. 12 grams NaOH was added and white fuming and foaming was seen. The color changed to a light orange tint. Then the plastic bits were added slowly. The flask had to be removed for a bit many times to prevent foam from spilling over but despite this the addition was easy. Then 500mL d-H<sub>2</sub>O was added to get the mass out and was poured into a beaker and stirred then filtered. 30% sulfuric acid was added slowly to produce a milky white precipitate and this was stopped once the pH was ~2. The precipitate was filtered with a cotton shirt and some was lost due to mechanical errors. This was then washed with more water and refiltered. Then it was placed in a glass dish and dried at low heat in the oven.

I only got 6.8 grams total and this seems to be a shitty yeild so I may try again some time. I also wonder if DMSO would work as the solvent.

chromium - 15-4-2006 at 05:08

Maybe more time and mixing when terephtahlaic acid is precipitated?

I do not know if this is related to your results but i did notice only very litle foaming when NaOH was added.

I did this in stainless steel vessel because NaOH at nearly 200C can probably dissolve glass.

[Edited on 15-4-2006 by chromium]

DeAdFX - 17-6-2006 at 18:01

Quote:

Originally posted by Quantum
I only got 6.8 grams total and this seems to be a shitty yeild so I may try again some time. I also wonder if DMSO would work as the solvent.

Quantum it has been awhile since this post. By any chance have you tried DMSO instead. I am having issues finding pure Ethylene Glycol but I can acquire DMSO no problem.

DMSO's boiling point is ~189 Celcius (wiki as source). hmmm 11c short. I'll give this a shot anywho. I just hope no DMSO/NaOH gets on me

.

[Edited on 18-6-2006 by DeAdFX]

Darkblade48 - 4-8-2006 at 13:19

Quote:

Originally posted by DeAdFX
DMSO's boiling point is ~189 Celcius (wiki as source). hmmm 11c short. I'll give this a shot anywho. I just hope no DMSO/NaOH gets on me

It's also been awhile since you last posted DeAdFX, I was wondering what the results were using DMSO as the solvent?

I'm just curious, as I bought some DMSO (for another purpose, actually) and remembered that you were going to try using DMSO as the solvent.

roamingnome - 25-11-2006 at 15:36

My Hero!

Some time ago I started compulsivly collecting PET, in the theory that it is more valuable or will become more valuable then say aluminium scap. Its a speciality chemical. I have 1000 projects on the shelf but but your refining the goods.

I hope this will inspire me to buy a grinder and go threw the 15 garbage bags that are now in my way.

Why PET?!!!! Try buying a 50 foot+ square PET tarp. Not the weave stuff, a mono film tarp. Only NASA has them, prove me worng so i can buy one.

An inflatable dome that is PVC will run you $4000+ (china inflatable)

Ok so work with me on how to get a tarp.

I want to dissolve the TPA in toulene(tobedetermined) and let the film spread out over a pond of water ( inside or whatever) then the linker (ethylene glycol) with acid or base catylst shall be sprayed in a fine mist causing the film to polymerize. If it was clear that would be nice and preferable. For use with greenhouses or personal blimps.

The other option is making or purchasing( i'd rather just collect it for free) PET rolls of any thickness and up to 8 foot across http://petfilm.com/

then ironing/glueing them together

Time time precious time..... i cant bloody do half of it

the imagination is quicker then reality

mericad193724 - 9-1-2007 at 17:27

Awesome synthesis, very OTC!

Is it possible to prepare phthalic anhydride from terephthalic acid?

I would like to use it in making Fluorescein

thanks,

Mericad

UnintentionalChaos - 9-1-2007 at 20:00

I don't think terephthalic acid can be converted to phthalic anhydride, at least by any simple means. I read that phthalic acid dehydrates at 210C to the anhydride. Phthalic acid can (supposedly) be made by oxidizing napthalene, available as mothballs, using chromate or permanganate.

chemoleo - 9-1-2007 at 21:54

Quote:

Originally posted by mericad193724
Awesome synthesis, very OTC!

Is it possible to prepare phthalic anhydride from terephthalic acid?

I would like to use it in making Fluorescein

thanks,

Mericad

No, this isn't possible. YOu'd have to change the entire ring-connectivity to achieve that.

Since an intramolecular anhydride of terephtalic acid cant exist (the benzene ring is not flexible, thus the distance between the carbonyls at 1 and 4 positions cant be bridged), I wonder whether an *inter*molecular anhydride of terephtalic acid can be prepared? This would be a polymer essentially. What happens upon excessive heating of terephtalic acid?

UnintentionalChaos - 9-1-2007 at 22:14

I'm pretty sure TPA sublimes when heated enough. The oxidation of napthalene seems workable I think. You would probably produce a mix of the isomers though (I know next-to-squat about organic chem) Use alcohol to remove the meta and ortho forms and leave behind the terephthalic acid. Heat the mix to 284C so pure phthalic anhydride vaporizes out of the mix and condense it (somehow). I suppose an alcohol wash would take any solid off the equipment afterward.

Picric-A - 21-12-2008 at 08:56

I have made two batches of TPA from PET bottles.
The only problem i have faced however is the drying of the TPA.
I find however many times i wash the crystals with cold water ( i did it about 7 times) there is always some remainding ethylene glycol which makes it extremly difficult to dry the crystals.
I have tryed squeezing it close to dry between cloth but it does nothing but loose precious TPA and its only removes a bit of the water/ethylene glycol.
Has anyone else had this problem and how did they sort it?
thanks

UnintentionalChaos - 21-12-2008 at 10:41

Picric- Why not dissolve in sodium hydroxide solution, dilute to several times the original volume, and acidify. It wont dry it out for you, but it'll get rid of the ethylene glycol. Can it be recrystallized directly from methanol or iPrOH?

[Edited on 12-21-08 by UnintentionalChaos]

Picric-A - 21-12-2008 at 11:30

I viewed the crystals under a microscope and they look like little sponges, no wonder they shrink to about 1/5th of their volume upon drying

UnintentionalChaos - Yes the dissolving in NaOH soloution workes but it takes longer, more acid and more alkali, so not really worth it.
I was looking for a way to try change their crystal structure, but i doubt there is a way. If anybody know anything that may help i think it would start an usefull conversation.

not_important - 21-12-2008 at 17:40

Drop the crude TPA in about 20 ml of water per gram of TPA, add a few drops of concentrated hydrochloric acid. Heat until on the edge of boiling, stirring well for at least 5 minutes and longer if it's easy. Let slowly cool, then chill if practical, filter.

Prolonged boiling seems to give a bit denser product, and gives the glycol a chance to diffuse out into solution. The added acid is to insure no alkali salts of TPA are left. The TPA does retain the solution, a second treatment omitting the HCl should reduce the amount of glycol and mineral acids quite low.

crazyboy - 10-1-2009 at 17:35

If I'm correct PET is made by the reaction of terephthalic acid and ethylene glycol. Why doesn't the TPA react with the ethylene glycol solvent to form PET?

sparkgap - 10-1-2009 at 18:35

You're essentially driving the esterification equilibrium (Le Chatelier''s, remember?) towards acid+alcohol instead of the ester. Also, a saponification like what chromium described is not likely to go backwards.

sparky (~_~)

Paddywhacker - 2-3-2009 at 14:43

This worked like a charm, though I'm still purifying the volumenous terephthalic acid precipitate, so I don't yet know the actual yield.

Has anybody tried a similar hydrolysis of Nylon? I've had a scrounge around but cannot find any suitable.

But what to do with the terephthalic acid?
I was thinking of pyrolyze a salt of it to try and get benzophenone with two COOH groups.

1. Form the half salt... 5g TPA + 2.6 g NaHCO3
2. Pyrolyze

or
1. Form the half methyl ester:- 5 g TPA + 1.1 ml MeOH
2. Form the sodium, calcium or barium salt of that
3. Pyrolyze.

or maybe a cross-pyrolysis with excess Sodium Acetate to give para (CH3CO)2C6H4

Any other ideas?

Edit:- Was filtered on the Buchner, washed with 500 ml H2O and then 250ml ethanol from the freezer. The ethanol extracted some sort of pink pigment. After drying on the Buchner for several hours, the yield was 27.3g of obviously damp product, pure white in the bulk but with a skin of slight pink. I'm going to heat it up with ethanol to remove the pink, cool in the freezer, and then re-filter, but it was obviously a successful prep.

Edit:- The product was dispersed in 200 ml of boiling EtOH which was then chilled in the freezer and the slurry refiltered on buchner. The product, after drying for 8 hours in a vacuum, weightd 20.85 g.

This is a yield of 110%. I wonder if there isn't some mono ethylene glycol ester of terephthalic acid in the product.
[Edited on 3-3-2009 by Paddywhacker]

[Edited on 4-3-2009 by Paddywhacker]

sparkgap - 2-3-2009 at 18:12

Nylon's an amide, so I'd think harsher conditions are needed for hydrolysis.

sparky (~_~)

Picric-A - 20-4-2009 at 09:57

Has anybody got access to this article? http://pubs.acs.org/doi/abs/10.1021/ie010563z
Seems a good way to anhydrous oxalic acid and (sodium) terephthalate.

On another note, does anybody know the solubility of sodium terephthalate in ethylene glycol? I intend on decarboxylating the acid so it seems a waste acidifying, filtering then neutralizing again when I want the sodium salt anyway! Not to mention a pain!

thanks

DJF90 - 26-4-2009 at 14:20

How did you figure that ANHYDROUS oxalic acid would be formed when the abstract mentions using concentrated NaOH solutions? The experimental section uses an autoclave at 160-250C, and also they use 20ml of water with a prescribed amount of NaOH (appears ~37% gives best yield of oxalic acid) for 0.67g of PET... and oxygen gas at 1-10 MPa. Conditions that are slightly out the way for us amatuers and also it doesnt look very scalable.

panziandi - 26-4-2009 at 14:31

Anhydrous oxalic acid? Obtained from an aqueous alkaline solution? Picric-A I think you might have some wires crossed lol! Really it seems a bit "idealistic green chemistry" kind of themed. You could always obtain your chemicals through your usual methods... :mad:

Picric-A - 27-4-2009 at 03:59

@ DJF90 - I guessed one could substitute the conc NaOH soloution for the easier NaOH dissolved in ethylene glycol, thus creating anhydrous conditions.

DJF90 - 27-4-2009 at 05:25

Generally such a swap may vastly affect the outcome of the reaction. You also forget that to get the free acid you need to acidify the sodium salt, which again is aqueous (I think they used 2N sulfuric IIRC to ppt. the terephthalic acid, the oxalic acid was determined in solution).

For the amatuer the best method (IMO) is the one outlined, it could have some minor changes possibly but in general it is a food procedure. The oxalic acid byproduct by doing the hydrolysis by this alternative method is not worth the additional hassle of reaction volume, use of autoclave etc etc, especially as the oxalic acid produced will be anything but anhydrous and can be purcased very cheaply either from a chemical supplier, hardware store, or even ebay.

UnintentionalChaos - 29-6-2009 at 07:42

Quote: Originally posted by Paddywhacker

Edit:- The product was dispersed in 200 ml of boiling EtOH which was then chilled in the freezer and the slurry refiltered on buchner. The product, after drying for 8 hours in a vacuum, weightd 20.85 g.

This is a yield of 110%. I wonder if there isn't some mono ethylene glycol ester of terephthalic acid in the product.
[Edited on 3-3-2009 by Paddywhacker]

[Edited on 4-3-2009 by Paddywhacker]

What was the original mass of PETE that you used? I wonder if it's just a calculation error. The "molar mass" of the original PETE is 192.168g/"mol" and the molar mass of terephthalic acid is 166.131g/mol.

[Edited on 6-29-09 by UnintentionalChaos]

bfesser - 29-6-2009 at 12:38

Hey, guys, let's not be too harsh. It may not be accessible to most amateurs, but it's something to read.

Thanks, Picric-A.

Attachment: ie010563z.pdf (94kB)
This file has been downloaded 1928 times

[Edited on 6/29/09 by bfesser]

DJF90 - 29-6-2009 at 13:36

I already read this before I told Picric-A its a useless article. The use of an autoclave to get terephthalic acid is pointless, especially when we have this method that is much simpler and works, courtesy of chromium.

panziandi - 29-6-2009 at 13:41

I have to agree I took a read of it too and I think it is much more than what is realistic to an amateur...

UnintentionalChaos - 29-6-2009 at 14:11

I have a large beaker of disodium terephthalate solution awaiting further purification at the moment. I don't have my notes with me, but I'll add in some details later when I have a yield.

I used diethylene glycol as solvent with dry NaOH prills in 25% excess of theoretical. Approximately 100mL of DEG, 25g NaOH (.625mol), and 48g of PET (0.25mol) were used. Depolymerization proceeded smoothly with heating in a stainless steel reaction vessel under constant stirring. There was constant evaporation of ethylene glycol from the reaction mix while heating for 20 minutes.The resultant off-white slurry dissolved in 400mL of water and about 4g of PET had not reacted after becoming encased in disodium terephthalate. Either longer heating or more vigorous stirring is required.

90g of 92% NaHSO4 dissolved in about 200mL of water was used to precipitate the free acid from solution as flocculent, white material. This was collected by vacuum filtration and redissolved in 22.62g of NaOH and an arbitrary amount of water (@400mL). I will reacidify and boil to form a more compact precipitate later on.

The diethylene glycol was from this product, which is sold as a chafing dish fuel:

http://www.candlefuel.com/pdf/CLC_Deg.pdf

As the MSDS shows, the only ingredient is DEG, without any dyes or water. I found that each can yields about 235mL, but needs filtration through real filter paper to remove stray fibers from the wick material. Coffee filter allows short pieces of the material through and it's too viscous to pass through cotton. Of course, if you filter the mixture after the heating, this isn't necessary, but I mean this more for other reactions.

Purchased locally, each can costs me $1. It'd be a waste of my time to boil the waste down unless I was doing this on a massive scale, since less than half a can (100mL) is enough solvent to handle 0.25mol of shredded PET.

Update: Okay, someone else who's done this, take a small sample and heat it intensely, like on the surface of a hotplate. Does it char or leave black residue?

The reason beaing that I was drying some of my product with heat last night (very high sublimation point, so why not crank it up?) and noticed a good deal of charring on the bottom of the evaporating dish.

So, I ramped up the heat until I got white fumes and no more water was condensing on a watch glass, moved the sample to a crystallizing dish, and sublimated it under atmosphere.

I got pale yellow, fluffy crystals. A small spatula, placed directly on the ceramic of my hotplate sublimated without residue when heated strongly.

I'm not exactly happy about whatever the yellow is, but I've eliminated whatever was charring.

[Edited on 7-2-09 by UnintentionalChaos]

Paddywhacker - 2-1-2010 at 13:22

The product is fiendishly insoluble in water, methanol, hexane & dichloromethane. Any ideas how to recrystallize it?

User - 2-1-2010 at 15:47

Terephthalic acid (benzene-1,4-dicarboxylic acid) [100-21-0] M 166.1, m sublimes > 3 0 0o
without melting, pK1
20 3.4, pK 2
20 4.34. Purify the acid via the sodium salt which, after crystallisation
from water, is re-converted to the acid by acidification with mineral acid. Filter off the solid, wash it with H2O
and dry it in a vacuum. The S-benzylisothiuronium salt has m 204o (from aqueous EtOH). [Beilstein 9 IV
3301.]

This is from the book : purification of laboratory chemicals 6e (2009).
It actually is the only way i found so far to clean this chemical

It is the same way that chromium used to crystallize it.
So maybe doing it a second time gives a quite pure product.
Especially because all the chems used are all very soluble in H2O.
I produced this same substance a few days ago and iam thinking of using this method somewhere these days.
Sadly enough i have no equipment available to test purity except for crude melting point determination.

Copper salt

turbosnigel - 13-2-2010 at 16:51

I prepared 16 Moles of Terephthalic acid by saponification with KOH in PG and then percipitate the TA with dilute H2SO4.

The TA was then washed with H2O and filtered a few times.

The Ta was then made in to its water soluble diamonium salt by a slight exes of ammonia.

The di amonium salt solution was left in a shed for some months to let the exes ammonia evaporate and the contaminant to aglomerate to some extent.

I suspect Bismuth used at about 2% as a catalyst in the polymerisation of TA to PET to constitute the colored contaminant. A 20 liter bucket of the crude di ammonium solution locks similar to tea in the color.

I then purified activated coal (Norit) by boiling in water so remove salts and other impurities as well as increasing its activity a few 100%

Repeated filtration with the purified activated coal made the solution clear.

I then purified an slight molar exes amount of copper sulfate solution by filtration with some purified activated charcol to eliminate insoluble (copperoxycloride and possibly som copperoxide?) and other cotaminating components.

The resulting clear blue solution was combined with the di ammonium terephthalic acid to percipitate a skye blue coppersalt of terephthalic acid.

Repeated washings and filtration trough a peace of cotton eliminated the soluble ammonium sulphate generated by the reaction. washings was repeated until the exes blue copper sulfate was no longer visible in the removed water.

(The particles are extremely small so filtration is rely a bitch!)

A half year after i started this i have quite a bit of a very pure non hygroscopic i insoluble copper salt with all its possible uses

Thanks for posting the info that made me realize i needed to do this

"TurboSnail"
>>>_@/"

Chemistry Alchemist - 11-9-2011 at 20:03

Quote: Originally posted by UnintentionalChaos

Phthalic acid can (supposedly) be made by oxidizing napthalene, available as mothballs, using chromate or permanganate.

What would the procedure be when doing it with Permanganate? really wanna preform the experiment but i dont know how to do so

DJF90 - 14-9-2011 at 17:01

Something akin to this procedure: http://cssp.chemspider.com/Article.aspx?id=270

theflickkk - 28-9-2011 at 21:05

I tried oxidising napthalene moth balls with KMnO4. I can't remember the exact details of the experiment as it was just an experiment to determine if a reaction even occurs.

A hot conc. KMnO4 solution was made and acidified with dilute sulfuric acid.
A moth ball was slowly lowered into the solution and some bubbling followed. The solution was left to cool for a day and I found that there was a white crust that formed on the surface of the solution. There was some brown residue present although much of the solution remained dark purple. It doesn't look as if there was much of a reaction but is there any way to test whether phthalic acid was formed? Initially I thought that an excess of napthalene was used but this is unlikely as the solution was still purple-ish. The napthalene moth ball remained largely intact also.

Chemistry Alchemist - 29-9-2011 at 02:26

i think you need to reflux it, just like how myst32YT Refluxed KMnO4 with Toluene to form Potassium benzoate and Manganese Dioxide, i think it will work the same way as that with this, Heating a acidified solution of permanganate with Naphthalene to react and make Manganese Dioxide and Potassium Phthalate when then is reacted with an acid to form Phthalic Acid and then dehydrated to form Phthalic Anhydride

Just a guess...

Waffles SS - 13-4-2012 at 01:12

What will be made if we use PP(Poly Propylene) instead of PET(Poly Ethylene)?

PHILOU Zrealone - 13-4-2012 at 05:47

Quote: Originally posted by Waffles SS

What will be made if we use PP(Poly Propylene) instead of PET(Poly Ethylene)?

Nothing! Wrong reading

!
*PET is Polyethyleneterephtalate thus a polyester ((-CH2-CH2-)n-O2C-C6H4-CO2-)
*PE is Polyethylene thus an alkane (-CH2-CH2-)n
*PP is Polypropylene thus an alkane (-CH(CH3)-CH2)n

Alkanes are relatively inert towards hydrolysis reagents what is not the case of polyesters!

Waffles SS - 13-4-2012 at 07:14

Sorry
I thought That is Poly ethylene but it seems i did mistake
Thank you