Dicyclohexylethyleneglycol, -diethyleneglycol, -triethyleneglycol, and related monosubstituted cyclohexanes. Conformational analysis using low-temperature ¹³C and ¹H NMR spectroscopy

Abstract

Two conformations of each of the title molecules have been detected by 100 MHz I3C NMR at 210 K. For the dicyclohexyl systems, the conformations are related via a single ring inversion. In each case the equatorial-axial conformer is 4.7 ? 0.4 kJ/mol less stable than the diequatorially substituted form in CD2CI2 solution. For monosubstituted models, the conformational free energy (-AGO) values of the -0-CH,-CH2-0CH3, -OCH,-CH2-0-CH,-CH,, and -0-CH2-CH2-0-CH-(CH,), groups have been determined to be 5.4.6.1, and 6.1 + 0.2 kJ/mol, respectively. In methanol, the latter equilibria are slightly more biased towards the axially substituted conformers.Key words: substituted ethylene glycols, conformational equilibria.

Phenolic Foams Toughened with Triethylene Glycol by In Situ Polymerization and Prepolymerization Processes

“…δ = 149.9–158.2 ppm at position a is assigned to the carbon connected to phenolic hydroxyl in the benzene ring, δ = 114.1–133.6 ppm at position b is assigned to the other carbons in the benzene ring, δ = 58.2–64.8 ppm at position e is assigned to the carbon in the hydroxymethyl, and δ = 35.7–34.1 ppm at position f is assigned to the carbon in the methylene connecting the benzene ring . The new peaks that appeared at position c (δ = 69.6–73.4 ppm) are assigned to the carbons in the methylene of TEG . The new peak at position d (δ = 65.6–68.6 ppm) of T-In-PR is assigned to the carbon in the methylene connecting the benzene ring and TEG.…”