Mechanism of Base-Catalyzed Resorcinol-Formaldehyde and Phenol-Resorcinol-Formaldehyde Condensation Reactions: A Theoretical Study

New Mechanism Proposed for the Base-Catalyzed Urea–Formaldehyde Condensation Reactions: A Theoretical Study

Base-catalyzed urea–formaldehyde condensation reactions were investigated by using a quantum chemistry method. It was found that monomethylolurea or N,N’-dimethylolurea can produce the methyleneurea intermediate (–HN–CO–N=CH2) with the catalysis of base. The E1cb (unimolecular elimination of conjugate base) mechanism was identified for the formation of such an intermediate. The potential energy...

Resorcinol-Formaldehyde (R-F) Resin

Resorcinol-formaldehyde resin "Russian Red" endodontic therapy.

Resorcinol-formaldehyde resin is a material used in endodontic therapy in many foreign countries. With immigration to the United States increasing, American dentists need to become familiar with resorcinol-formaldehyde therapy. It contains two potentially toxic components, formaldehyde (liquid) and resorcinol (powder). Zinc oxide or barium sulfate may be used for radiopacity. When 10% sodium hy...

Synthesis, Characterization and Composites from Resorcinol-urea-formaldehyde-casein Resin

condensation reaction of urea, casein and formaldehyde in the presence of varying proportion of resorcinol under alkaline condition. All the prepared resins were characterized by free-formaldehyde content, free-phenol content, viscosity measurements and infrared spectroscopy (IR). The resin samples were cured isothermally at 120oC using two different curing agents, p-toluene sulphonic acid (PTS...

Theoretical Confirmation of the Quinone Methide Hypothesis for the Condensation Reactions in Phenol-Formaldehyde Resin Synthesis

The mechanisms for the base-catalyzed condensation reactions in phenol-formaldehyde resin synthesis were investigated by using the density functional theory method. The structures of the intermediates and transition states, as well as the potential energy barriers of the involved reactions, were obtained. The hypothesis of quinine methide (QM) formation was theoretically confirmed. Two mechanis...