Sciencemadness Discussion Board

cyclic diester

ProChem - 4-8-2009 at 07:00

I have dimethyl ester ofadipic acid and ethylene glycol to make a cyclic diester (MSA is catalyst). any suggestions how one can avoid making a polymer?

sonogashira - 4-8-2009 at 08:08

High dilution with ethylene glycol will make cyclization more probable, but i do not know if the yield will be very high even still. Are 10-membered rings are very favorable? I would not imagine but i am not sure. But it is a known product i assume?

[Edited on 4-8-2009 by sonogashira]

sparkgap - 4-8-2009 at 21:34

Remember that forming rings larger than five or six atoms is not as kinetically or thermodynamically facile. I suggest looking into past work, e.g. http://www.google.com/patents?&vid=USPAT2092031&id=7... :)

HTH

sparky (~_~)

JohnWW - 4-8-2009 at 22:58

Because of the mutual angle for tetrahedral sp3 bonding of 109º28', 5-membered (108º) and after that 6-membered (120º) rings are usually most favored energetically, if all four groups attached at the central sp3 atom are of similar size and polarity. Even then, 6-membered rings, and even more so 7-membered and larger rings, with all single bonds,, flex considerably out-of-plane in order for the constituent atoms to approach a bonding angle close to 109º28'.

[Edited on 5-8-09 by JohnWW]

ProChem - 14-10-2009 at 11:59

Shortly after I posted the question I found many patents I reacted sebacic acid and ethylene glycol (EG) with ptsa to make a polyester. The second step I heated the polyester with titanium isopropoxide under vacuum. Success! the next project I used 1,4-butane diol instead of EG. This time it didn't work however I collected THF as a product.

ammonium isocyanate - 14-10-2009 at 15:03

Could we see a write-up of your reaction?

Morgan - 8-1-2014 at 17:00

Quote: Originally posted by ProChem  
Shortly after I posted the question I found many patents I reacted sebacic acid and ethylene glycol (EG) with ptsa to make a polyester. The second step I heated the polyester with titanium isopropoxide under vacuum. Success! the next project I used 1,4-butane diol instead of EG. This time it didn't work however I collected THF as a product.


Tidbit on sebacic acid and glycerol -didn't know where to post this.
Surgical Glue to Mend Broken Hearts
http://www.technologyreview.com/news/523356/surgical-glue-to...