The Solubilities of the Normal Saturated Fatty Acids. Iii

Abstract

Previous reports from this laboratory (1, 2) have presented the solubilities of the normal saturated fatty acids from caprylic to stearic, inclusive, in benzene, cyclohlexane, tetrachloromethane, trichloromethane, ethyl acetate, butyl acetate, glacial acetic acid, acetone, 2-butanone, methanol, 95% ethanol, isopropanol, nbutanol, nitroethane, acetonitrile, and water. In view of the usefulness of such data, the scope of this investigation has been expanded to include a number of the more common aromatic solvents, as well as several simple, substituted hydrocarbons. This paper reports the solubilities of caprylic, capric, lauric, myristic, palmitic, and stearic acids in toluene, o-xylene, chlorobenzene, nitrobenzene, 1,4-dioxane, furfural, 1 ,2-dichloroethane, and nitromethane. EXPERIMENTALThe lauric and myristic acids used in this investigation were those employed in tho previous studies (2). The caprylic and capric acids were obtained by vacuum fractionation of Armour Neo-Fat 7 and Neo-Fat 15, respectively, in a Stedman packed column. The stearic acid was prepared by repeated recrystallization of Armour Neo-Fat 1-65 from acetonitrile. The freezing points of these highly purified fatty acids are listed in Table I. These values are in good agreement with, and in most cases exceed, the best freezing points reported for these compounds.The solvents which were used were twice distilled from the best grade of commercial producl,s, those with higher boiling points being distilled under reduced pressure. The boiling points and refractive indices of these solvents were in good agreement with the data in the International Critical Tables.The solubilities of the fatty acids were determined by the methods described previously (3-5). RESULTS AND DISCUSSIONThe solubilities of the fatty acids in the benzene derivatives, toluene, o-xylene, chlorobenzene, and nitrobenzene, are listed in Table 11-V, respectively, and the solubilities in toluene and in nitrobenzene are shown graphically in Figs. 1 and 2, respectively. The solubilities in toluene, o-xylene, and chlorobenzene are remarkably similar in spite of the fact that the first two solvents possess only a very slight polarity while the third is a moderately polar solvent. Upon an equimolar basis these solubilities are practically identical, indicating that moderate differences between the respective polarities of the solvent and solute exert much less influence upon the solubilities of the fatty acids than do other factors, such as the relative internal pressures of the molecules, intermolecular attractive forces, etc. The relatively high polarity of nitrobenzene, on the other hand, results in somewhat lower solubilities of the fatty acids. The high polarity of the solvent, however, is accompanied by other changes in its physical properties, such as in- 603

Self-selection of dissipative assemblies driven by primitive chemical reaction networks

“…1 , Supplementary Table 3 and Methods section for description of the model). The anhydride solubility was found to decrease roughly an order of magnitude per two carbon numbers (11, 1.0, and 0.05 mM for C 4 C 4 , C 5 C 5 , and C 6 C 6 , respectively), which is in line with findings for aliphatic carboxylic acids 26 and alcohols 27 . These solubilities matched the turbidity data well, considering that when the concentration anhydride fell below the solubility limit, we observed no more increased turbidity (Supplementary Fig.…”

Caprylic and Polygalacturonic Acid Combinations for Eradication of Microbial Organisms Embedded in Biofilm

“…Other than for E. coli ( Figure 2 ), there was no significant impact of increasing the CAP concentration from 0.1 to 0.4% on biofilm eradication when no PG was present. This is consistent with the reported aqueous solubility limit of CAP of approximately 0.07% ( Hoerr et al, 1946 ), hence once the CAP concentration approached saturation there was little impact on biofilm eradication from having insoluble CAP present. Although PG alone demonstrated inhibitory activity against planktonic P. aeruginosa , MRSA, and E. coli there was no appreciable antimicrobial effect against P. aeruginosa , E. coli , and MRSA biofilms.…”

“…A hypothesis for the enhanced synergy seen with 0.4% CAP in combination with PG may be that the apparent solubility of CAP is enhanced in the PG + CAP combination and the bioavailability of both CAP and PG within biofilms is significantly increased when combined. At 0.4% concentration, CAP alone (without PG) showed visible signs of phase separation or immiscibility and was well above the reported aqueous CAP solubility limit of 0.07–0.08% at 25°C ( Hoerr et al, 1946 ). This is also consistent with the minor differences in antimicrobial activity seen between CAP alone at 0.1 and 0.4% in Figure 1 where soluble CAP might have saturated.…”

“…Antimicrobial solutions were prepared containing 1% PG (Sigma-Aldrich, St. Louis, MO, United States, <15% esterified) + either 0.1 or 0.4% CAP (Sigma-Aldrich, St. Louis, MO, United States). 0.1% CAP was selected because it was near the reported aqueous solubility limit for CAP ( Hoerr et al, 1946 ). The emulsifying capacity of pectins for lipids has been reported near 40% or more ( Liang et al, 2015 ), hence 1% PG and 0.4% CAP (40% of the PG concentration) were selected for testing since 0.4% CAP was well above the solubility limit of CAP and therefore presented the potential for increasing the effective concentration of CAP presented to microbes.…”

On the Mechanism of Extractive Electrospray Ionization

“…Besides, the solubility of fatty acids is reported to be higher in methanol compared to acetonitrile. 34,36 The ESI response of fatty acids in protic solvents is much higher than in aprotic solvents based on previous reports. 38,39 However, for all fatty acids, we found that the EESI response of fatty acids dissolved in acetonitrile was indeed much higher than in methanol.…”