Organocatalytic synthesis of (poly)hydroxyurethanes from cyclic carbonates and amines

DFT investigation of the reaction mechanism for the guanidine catalysed ring-opening of cyclic carbonates by aromatic and alkyl-amines

“…The Gibbs energy for the uncatalysed aminolysis of PC evolves in the following order DG(methylamine) < DG(cyclohexylamine) < DG(aniline). Those results are consistent with previous experimental studies 19,20,22 reporting that linear alkylamines are more reactive than cyclic amines and aromatic amines. The higher DG value determined for the ring opening of PC by less nucleophilic aniline is related to the lower partial charge on the nitrogen atom of the aromatic amines compared to the aliphatic ones.…”

“…Organocatalysts such as TBD (1,5,7-triazabicyclo[4.4.0]dec-5-ene), phosphines, phosphazenes and cyclohexylphenyl thiourea were found to display a higher efficiency than inorganic Lewis acids (MgBr 2 , FeCl 3 , Fe(OTf) 3 .). The same conclusion was drawn from the investigation of Lambeth et al 19 who found TBD as the most potent organocatalyst to fasten the step-growth polymerization of biscyclic carbonates and amines. In addition, PHUs synthesized in the presence of TBD at room temperature showed higher molar mass than the corresponding polymers produced in the absence of catalyst.…”

“…In particular, the chemical structure of the amine has a signicant impact on the reaction/polymerization rates and yields. [19][20][21][22] Moreover it was shown that aryl amines are less reactive or even non-reactive towards cyclic carbonates compared to the aliphatic ones. Although nucleophilic alkylamines induce ring opening of cyclic carbonates, this aminolysis reaction is generally slow and the use of catalysts able to activate the cyclic carbonate is generally required to accelerate the reaction.…”

How to explain low molar masses in PolyHydroxyUrethanes (PHUs)

“…One way to obtain PHUs with high molar masses could be to work at low temperature with a catalyst able to activate the carbonate and not the amine during the reaction. Recent papers [39,40] tend to confirm this possibility. Another way is to use other carbonates such as 6-membered cyclic carbonates (6CC) [38,41], or even 7-membered cyclic carbonates (7CC) [21] but they are much more difficult to obtain compared to 5CC.…”

Synthesis of Bi- and Trifunctional Cyclic Carbonates Based on Trimethylolpropane and Their Application to Networked Polyhydroxyurethanes

“…In particular, five-membered cyclic carbonates (5-CCs) can be derived from epoxides and CO 2 under mild conditions (Fleischer, 2013;Sheng, 2015) and therefore, numerous 5-CCs-derived PHUs have been synthesized using bisphenol A (Ochiai, 2014;Lambeth, 2013;Kihara, 1996) and bio-based polyols (Kathalewar, 2015;Annunziata, 2014;Guillaume, 2013;Guillaume, 2011) as starting materials. PHUs can be functionalized by the use of functional diamines or by chemical modifications via their hydroxyl side chains.…”