High-Pressure Raman Noncoincidence Effect and Conformation of Alkyl Side Chain in Alkyl Benzoates was written by Slager, Vivian L.;Chang, Hai-Chou;Kim, Yoo Joong;Jonas, Jiri. And the article was included in Journal of Physical Chemistry B in 1997.Category: esters-buliding-blocks The following contents are mentioned in the article:
The Raman noncoincidence effect has been used to investigate the changes in intermol. interactions induced by applying high pressure to neat liquid alkyl benzoates. The noncoincidence of the carbonyl band of a homologous series of straight chain alkyl benzoates (Me, Et, Pr, Bu, and hexyl benzoate) and a branched chain alkyl benzoate (2-ethylhexyl benzoate) was measured at 20 and 40 °C over the pressure range 1-5000 bar. The d. was measured as a function of pressure for all mols. A transition point dividing the noncoincidence behavior as a function of d. into two regions was found, for all mols. except Me benzoate. Below the transition point, at lower d., the noncoincidence value was relatively insensitive to changes in d., while above the transition point, the noncoincidence value dropped sharply with increasing d. The decrease in the value of noncoincidence above the transition point was interpreted as the change in intermol. interactions resulting from the conformational change in favor of a “folded” form of the alkyl side chain shielding the carbonyl group. To examine the plausibility of the presence of energetically allowable conformations with a folded alkyl side chain, conformational searches based on mol. mechanics calculations have also been performed. The strain energy of some alkyl benzoate conformers with folded side chain was calculated to be within a few kcal/mol of the global min. conformation. Both the exptl. results and the conformational anal. suggest that the population of the folded conformer increases under high-pressure conditions owing to its compactness. This study involved multiple reactions and reactants, such as 2-Ethylhexyl benzoate (cas: 5444-75-7Category: esters-buliding-blocks).
2-Ethylhexyl benzoate (cas: 5444-75-7) belongs to esters. Esters are widespread in nature and are widely used in industry. In nature, fats are in general triesters derived from glycerol and fatty acids. Esters are responsible for the aroma of many fruits, including apples, durians, pears, bananas, pineapples, and strawberries. Esters contain a carbonyl center, which gives rise to 120° C–C–O and O–C–O angles. Unlike amides, esters are structurally flexible functional groups because rotation about the C–O–C bonds has a low barrier. Their flexibility and low polarity is manifested in their physical properties; they tend to be less rigid (lower melting point) and more volatile (lower boiling point) than the corresponding amides. Category: esters-buliding-blocks
Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics