(170) Condensation of Xylene-Formaldehyde Resin with Phnol.

Prebiological Formaldehyde Condensation

A definition of the term " l i f e " , if understood as one element in a supposed class of extraterrestrial and prebiological phenomena, is shown to be logically impossible because life is the sole known element of that class. Instead, the properties of the class of "b io ids" , defined as the class of " open systems which can exist in several steady states" (DECKER and SPEIDEL, Chemiedozentent...

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...

dimethylhydantoin-formaldehyde resin and polyvinylpyrrolidone

Berlin, A. and Smeets, J. (1974). European intercomparison programmes and harmonization oftechniqueswith special reference to heavy metals in biological fluids. Presented at the Fourth Annual Symposium onRecent Advances in the Analytical Chemistry of Pollutants, Basle, Switzerland. Bryce-Smith, D. (1972). Behavioural effects of lead and other heavy metal pollutants. Chemistry in Britain, 8, 240...

Resorcinol-Formaldehyde (R-F) Resin

The mechanism of the condensation of formaldehyde with tetrahydrofolic acid.

The bell-shaped pH rate profile for the reaction of tetrahydrofolic acid with formaldehyde to form 5, lo-methylene tetrahydrofolic acid has been shown to result from a change in rate-determining step with changing acidity. In alkaline solution, the rate-determining step is the acid-catalyzed dehydration of hydroxymethyl tetrahydrofolic acid and its conjugate base. This step is subject to genera...