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

Printable Version  
Author: Subject: PVA --> PVC
quest
Hazard to Self
**




Posts: 75
Registered: 15-9-2003
Member Is Offline


[*] posted on 1-1-2005 at 12:43
PVA --> PVC


Hi, my knowledge on polymers is very low.

I want to make Polyvinyl chloride (PVC) and the cheapest material I could think of to start with is Polyvinyl acetates (PVA).

Is there any way to synthesis the PVC from the PVA?
View user's profile View All Posts By User
kclo4
International Hazard
*****




Posts: 909
Registered: 11-12-2004
Location:
Member Is Offline


[*] posted on 1-1-2005 at 14:41


it looks like you could add hcl to it

[C4H6O2]n + hcl = [C2H3Cl]n = c2h4o2

mind to tell me why




View user's profile Visit user's homepage View All Posts By User
JohnWW
International Hazard
*****




Posts: 2849
Registered: 27-7-2004
Location: New Zealand
Member Is Offline


[*] posted on 1-1-2005 at 15:04


PVA also means polyvinyl alcohol, a water-soluble usually low-molecular-weight polymer used as a glue.

In view of the reaction with simple monomeric primary and secondary alcohols to produce alkyl chlorides (and with carboxylic acids to produce acyl chlorides), it may just be possible to convert a grade of polyvinyl alcohol, of sufficiently low molecular weight to dissolve in a mutually suitable polar solvent with a reasonably high boiling-point and which does not contain -OHs or labile Hs, to the corresponding low-molecular-weight PVC polymer by reaction with thionyl chloride, SOCl2. Byproducts would be SO2 and HCl. Possible solvents for such a reaction are dioxane (and other ethers although ethyl ether would be much too volatile), ketones (acetone may be too volatile), carbon tetrachloride, dimethyl sulfoxide. It may be possible to do the reaction by adding the polyvinyl alcohol directly to the SOCl2, which is liquid up to 78.8ºC, but this is about the temperature to which the mixture has to be heated under reflux for the reaction, and there may be a danger of excessive heat being generated resulting in SOCl2 boiling away.
View user's profile View All Posts By User
neutrino
International Hazard
*****




Posts: 1583
Registered: 20-8-2004
Location: USA
Member Is Offline

Mood: oscillating

[*] posted on 1-1-2005 at 15:09


Why do you want to make your own PVC? It’s readily available in the form of big, cheap pipes at hardware stores. As for your reaction, it would look like this:

[-CH2-CH(OOCCH3)-]n(s) + nHCl(aq) -> nCH3COOH(aq) + [CH2-CHCl-]n(s)

The reaction might work, but due to the fact that PVC is a solid, it would be confined to the surface of the chunk of PVA you’re trying to convert. You might be able to find an inert solvent that would dissolve the PVA, but I doubt it would be OTC.
View user's profile View All Posts By User
quest
Hazard to Self
**




Posts: 75
Registered: 15-9-2003
Member Is Offline


[*] posted on 2-1-2005 at 06:11


Quote:

Why do you want to make your own PVC? It’s readily available in the form of big, cheap pipes at hardware stores


I want pure PVC, and pipes are too contaminated.
And at my chem store its very expensive.


As for using HCl but I was told it wont work :-/
I will try it and see what happen :)

BTW, is there any indicator for PVC?
View user's profile View All Posts By User
Rajinder Singh Gujral
Harmless
*




Posts: 3
Registered: 3-1-2005
Member Is Offline


[*] posted on 4-1-2005 at 02:49
CONVERSION OF pva to pvc


Commercially viable method is avaialble for this conversion using Thionylchloride and DMF ( as catalyst). PVA is heated with these and finally distilled to get pure PVC.
View user's profile View All Posts By User

  Go To Top