I'm dealing with a work that ring-opening reaction of GMA is the basic reaction to get my resultants. As you know, water can act as a mild acid in the high temperature (70 to 80 C), thereby accelerating the ring-opening of GMA. But, the hydrolysis of epoxide and its protonation at high pH (DMSO) may lead to an imperfectness reaction. In addition, high pH may cause the transesterification instead covalent ring-opening. My hypothesis is the reaction of carboxlic group with the epoxide (GMA) in the water medium at the pH 6 to 7 at 75 C. How much should I be worried about transesterification or occuping the epoxide by OH (from water) instead carbolxic group (from my reagent)?
Thank you in advance.
As no one has reached my query, I coped with it recently, and i'd like to share with all fellow. Please find the attached file that might lead you all regarding my query.
Medium for glycidyl methacrylate ring opening for reacting with carboxylic group will be DMSO because the reactants must be soluble in solvent to form uniform solution.
Dear Kambiz,
I would like to know how did you deal with the unwanted reaction of GMA with water molecules by transesterification reaction at your reaction condition. I will be thankful if you could share it.
You could use higher excess molar ratio of GMA to compensate its unwanted reaction with water molecule.
The likelihood of transesterification is higher in an alkaline medium, even though GMA normally undergoes partial transesterification when water is the medium. I maintained the reaction at a low pH to prevent this unwanted reaction (the paper in my first comment detailed the mechanism). However, it was still not the case in my approach because the acrylic group of GMA was first covalently immobilized on the surface of the PP polymer film, and the oxirane ring was thereafter exposed to the functional compound. The grafting of GMA on PP lowered the accessibility of the ester group of GMA.
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