The influence of reaction variables on the formation of polyhydroxybenzene diazonaphthoquinone sulfonate esters was investigated. Solvent polarity, base, reactant concentration and reaction temperature were all found to have large effects. High solvent polarity was observed to promote formation of highly esterified products. The condensation of 2,3,4-trihydroxybenzophenone with diazonaphthoquinone sulfonyl chloride in dimethylacetamide or N-methyl-2-pyrrolidone resulted in a diester isomer distribution that was different than that observed in acetone, 1,4-dioxane, methyl ethyl ketone, tetrahydrofuran and gamma-butyrolactone. Further, the initial sulfonate esters were formed under kinetic control. In the presence of base and 2,3,4-trihydroxybenzophenone the esters equilibrated to form a common, thermodynamically favored mixture. The equilibration rate was fast in solvents having high polarity. An equilibration scheme is proposed involving phenolate ion displacement processes.
Changes in phenolic-formaldehyde resin properties are described in terms of thermal exposure. At high temperature, resin molecular weight, dissolution properties and chemical composition change depending on the presence or absence of monomers. Without monomer in the resin melt at 220 degree(s)C, resin molecular weight increases with a corresponding decrease in dissolution rate. In the presence of monomer, molecular weight generally decreases. Dissolution rate may fluctuate depending on the monomer mixture. Three,five- Xylenol and 2,3,5-trimethylphenol co-monomers induced the most extreme changes in resin properties with thermal treatment. Resin degradation-recombination processes suggest a classical Friedel-Craft rearrangement mechanism.