Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
Author: Subject: Benzene from plastic?
Chemistry Alchemist
Hazard to Others
***




Posts: 403
Registered: 2-8-2011
Location: Australia
Member Is Offline

Mood: No Mood

[*] posted on 9-9-2011 at 09:41
Benzene from plastic?


OK so there will be alot of people asking me why i want to know this but its for educational purposes ok.

Now PET Plastic or polyethylene terephthalate is a very easy to get, a soft drink bottle contains around 70%+ of it so it is easy to get alot of it, is it possible to react it some how with ethylene glycol to form terephthalic acid and then react that to form Benzene? it sounds like a pretty good and cheap method...

also, Phthalic Acid is used in making Luminol, and terephthalic acid is one of 3 isomers of Phthalic Acid, is it possible to make Phthalic Acid from Terephthalic Acid? i know this is off topic alot but how would you also catalytic oxidate Naphthalene directly into Phthalic Acid?




View user's profile Visit user's homepage View All Posts By User
fledarmus
Hazard to Others
***




Posts: 187
Registered: 23-6-2011
Member Is Offline

Mood: No Mood

[*] posted on 9-9-2011 at 10:26


It is certainly possible to break polyethylene terephthalate back into its component parts, ethylene glycol and terephthalic acid. It's just an ester linkage, and those can be broken under a wide variety of conditions. Here is one industrial process:

http://www.nd.edu/~enviro/design/pet.pdf

Based on this paper, it seems possible that terephthalic acid could be decarboxylated to benzene:

http://pubs.acs.org/doi/abs/10.1021/ef0400722

And you're right, the question is why? Benzene is much cheaper than terephthalic acid, and there are much better ways to synthesize it.

Terephthalic acid is benzene substituted with a carboxylic acid group in the 1 and 4 positions. Phthalic acid is substituted in the 1 and 2 positions. The easiest way I can think of to go from terephthalic acid to phthalic acid, would be to get rid of both of the carboxylic acid groups (to make benzene), then put them back on. But again, why?

And yes, naphthalene can be oxidized directly to phthalic acid:

http://www.sciencedirect.com/science/article/pii/S0040403905...

There are other papers which use various chlorates as oxidizing agents
View user's profile View All Posts By User
Nicodem
Super Moderator
*******




Posts: 4230
Registered: 28-12-2004
Member Is Offline

Mood: No Mood

[*] posted on 9-9-2011 at 11:00


Chemistry Alchemist, please start to UTFSE and also open thread in the appropriate forum sections. Referenceless and beginners threads should only be opened in the Beginnings section.
View user's profile View All Posts By User
Nicodem
Super Moderator
Thread Moved
9-9-2011 at 11:00
Chemistry Alchemist
Hazard to Others
***




Posts: 403
Registered: 2-8-2011
Location: Australia
Member Is Offline

Mood: No Mood

[*] posted on 9-9-2011 at 18:19


Sorry that is UTFSE? When do u use the other forum section?



View user's profile Visit user's homepage View All Posts By User
bfesser
Resident Wikipedian
*****




Posts: 2114
Registered: 29-1-2008
Member Is Offline

Mood: No Mood

[*] posted on 9-9-2011 at 18:25


What Nicodem is saying is that you should use the forum search function <em>and</em> a common search engine (e.g. <a href="http://www.google.com/">Google</a>;) before starting any new thread to see if a topic has already been covered.

http://www.sciencemadness.org/member_publications/terephthal...

http://www.sciencemadness.org/member_publications/benzene_pr...

[Edited on 9/10/11 by bfesser]
View user's profile View All Posts By User
Chemistry Alchemist
Hazard to Others
***




Posts: 403
Registered: 2-8-2011
Location: Australia
Member Is Offline

Mood: No Mood

[*] posted on 9-9-2011 at 18:34


Quote: Originally posted by fledarmus  
It is certainly possible to break polyethylene terephthalate back into its component parts, ethylene glycol and terephthalic acid. It's just an ester linkage, and those can be broken under a wide variety of conditions. Here is one industrial process:


The reason why im asking about benzene is jsut wondering other possible routes to making it, it is a 95% chance im not going to carry out this coz i dont have proper equipment, but if it was simple and non hazard's which it would be then i would do it but most likely not...




View user's profile Visit user's homepage View All Posts By User
Chemistry Alchemist
Hazard to Others
***




Posts: 403
Registered: 2-8-2011
Location: Australia
Member Is Offline

Mood: No Mood

[*] posted on 9-9-2011 at 18:42


Quote: Originally posted by fledarmus  

Terephthalic acid is benzene substituted with a carboxylic acid group in the 1 and 4 positions. Phthalic acid is substituted in the 1 and 2 positions. The easiest way I can think of to go from terephthalic acid to phthalic acid, would be to get rid of both of the carboxylic acid groups (to make benzene), then put them back on. But again, why?


Phthalic Acid is converted to phthalic anhydride to make Luminol, i wanted to know id i can skip a few steps in the Luminol reaction and substitute them for my own steps... and by substitute i mean change nurdrages method around




View user's profile Visit user's homepage View All Posts By User
Chemistry Alchemist
Hazard to Others
***




Posts: 403
Registered: 2-8-2011
Location: Australia
Member Is Offline

Mood: No Mood

[*] posted on 9-9-2011 at 18:49


How would i oxidize Naphthalene? ive got about 50 grams of the stuff just laying around and like to convert it to phthalic acid, its looked around about using Potassium Permanganate in a acetic medium will produce Phthalic acid, and in alkiline medium, it produces somthing else, so how would you do it?



View user's profile Visit user's homepage View All Posts By User
Nicodem
Super Moderator
*******




Posts: 4230
Registered: 28-12-2004
Member Is Offline

Mood: No Mood

[*] posted on 10-9-2011 at 00:05


Quote: Originally posted by Chemistry Alchemist  
How would i oxidize Naphthalene?

Why do you ask questions when you don't read the answers? You were already given a sound advice, so start applying it: UTFSE!
Quote:
When do u use the other forum section?

You can choose the section according to the contents of the thread you are about to open. For example, threads with the original post lacking any references, containing beginner's or unanswerable questions should be opened in the Beginnings section. Likewise, when you desire a comprehensive pedagogic assistance rather than just simple answers, the Beginners section is much more appropriate than any other section, as the discourse here is more adaptable to the needs of the original poster. For example, if you ask an unanswerable question (a question lacking sufficient information for having a possible answer) you might get ignored in other forum sections, or worse, get flamed for wasting other member's time, while here in Beginnings section you can instead get a more appropriate reply describing in detail what other information is required for an answer.




…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)

Read the The ScienceMadness Guidelines!
View user's profile View All Posts By User

  Go To Top