Determination of Asphaltene Critical Nanoaggregate Concentration Region Using Ultrasound Velocity Measurements was written by Svalova, Aleksandra;Parker, Nicholas G.;Povey, Malcolm J. W.;Abbott, Geoffrey D.. And the article was included in Scientific Reports in 2017.Quality Control of Methyl heptanoate The following contents are mentioned in the article:
Asphaltenes constitute the heaviest, most polar and aromatic fraction of petroleum crucial to the formation of highly-stable water-in-crude oil emulsions. The latter occur during crude oil production as well as spills and cause difficulties to efficient remediation practice. It is thought that in nanoaggregate form, asphaltenes create elastic layers around water droplets enhancing stability of the emulsion matrix. Ultrasonic characterization is a high-resolution non-invasive tool in colloidal anal. shown to successfully identify asphaltene nanoaggregation in toluene. The high sensitivity of acoustic velocity to mol. rearrangements and ease in implementation renders it an attractive method to study asphaltene phase properties. Currently, aggregation is thought to correspond to an intersection of two concentration-ultrasonic velocity regressions. Our measurements indicate a variation in the proximity of nanoaggregation which is not accounted for by present models. We attribute this uncertainty to physico-chem. heterogeneity of the asphaltene fraction driven by variation in mol. size and propose a critical nanoaggregation region. We treated asphaltenes from North and South American crude oils with ruthenium ion catalyzed oxidation to characterize their n-alkyl appendages attached to aromatic cores. Principal component anal. was performed to investigate the coupling between asphaltene structures and velocity measurements and their impact on aggregation. This study involved multiple reactions and reactants, such as Methyl heptanoate (cas: 106-73-0Quality Control of Methyl heptanoate).
Methyl heptanoate (cas: 106-73-0) belongs to esters. Esters are also usually derived from carboxylic acids. It may also be obtained by reaction of acid anhydride or acid halides with alcohols or by the reaction of salts of carboxylic acids with alkyl halides. Acyl chlorides and acid anhydrides alcoholysis is another way to produce esters. Acyl chlorides and acid anhydrides react with alcohols to produce esters. Anydrous conditions are recommended since both acyl chlorides and acid anhydrides react with water.Quality Control of Methyl heptanoate
Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics