Correlation between Apparent pH and Acid or Base Concentration in the ASTM Medium

Popovych, Orest

doi:10.1021/ac60210a051

Cited by 19 publications

(11 citation statements)

References 33 publications

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“…used in standard methods for determining the acid and base numbers of petroleum products [44], as well as in determining the acid numbers of marine and vegetable oils [45], consists of 50.0 percent of toluene, 49.5 percent of isopropanol, and 0.5 percent of water, by volume. The dielectric constant is about 8 [46]. In the area of fundamental investigations, Fuoss and co-workers have been investigating electrolyte-solvent interactions systematically since about 1950, using various mixed solvents so as to gain insight into interactions between solvents as well as between solvent and solute [47][48][49].…”

Section: Formamidementioning

confidence: 99%

Acid-base behavior in aprotic organic solvents

Davis¹

1968

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Butyl hydroperoxide and deuteroperoxide. Deuterium isotope effects on hydrogen bonding by Br0nsted acids 40 4.3. Hydrogen-bonded ion pairs 41 4.3.1. Conductance 41 a. Walden's work 42 b. Wynne-Jones' postulate 42 c. Investigations of Kraus, Fuoss, and associates... 43 d. Summary 45 4.3.2. Dielectric constants 46 a. Dielectric polarization of substituted ammonium picrates and halides in benzene 46 b. Dielectric polarization of other acid-base complexes in benzene 47 4.3.3. CoUigative properties 49 a. Cryoscopy 50 Page b. The differential vapor pressure (DVP) method... 51 104 4.5.6. Homoconjugation of other organic and inorganic acids a. Perchloric acid 105 b. Other acids 105 4.5.7. Heteroconjugate anions 105 a. Chemical behavior 105 b. Physical measurements 108 4.6. Concluding discussion of hydrogen bonding 112 4.6.1. Definition of a hydrogen bond. Systems which form hydrogen bonds 112 4.6.2! Some recent concepts of hydrogen bonding 113 5. Acidity and basicity scales in aprotic organic solvents... 114 5.1. Early attempts to determine relative acidities 114 5.2. Log Kbha scales of acidity and basicity 115 5.3. Methods used in determining values of log A^bha 116 5.4. Tables of log ^bha, and AS obtained using aprotic solvents 118 5.4.1. Aromatic and substituted aromatic hydrocarbons 118 a. Benzene 118 b. Anisole and chlorobenzene 126 5.4.3. Carbon tetrachloride 126 5.4.4. Chloroform 128 5.4.5. Miscellaneous aprotic solvents 129 6. Acid-base titrations in completely aprotic solvents 133 6.1. Introduction 133 6.2. Titrations with indicator dyes in completely aprotic solvents 133 6.3. Instrumental procedures for detecting end-points in completely aprotic solvents 133 6.3.1. Conductance titrations 133 iv Contents -Continued Page 6.3.2. Dielectrometric titrations 133 6.3.3. Photometric titrations 134 6.3.4. Thermometric titrations 135 6.3.5. Titrations by the DVP method 135 6.3.6. Cryoscopic titrations 135 6.3.7. Other possible instrumental procedures 135 a. Refractive index 135 b. Density 135 c. Optical rotation 135 6.4. Reference acids and bases for aprotic organic solvents 135 6.4.1. Acids 135 a. Hydrogen chloride 135

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Section: Formamidementioning

confidence: 99%

Acid-base behavior in aprotic organic solvents

Davis¹

1968

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“…hledium effects for several electrolytes were derived from their solubility (ion-activity) products, K,,, in water and methanol (Equation 8). Some of the K,,'s and medium effects, calculated from our solubility data on a molar scale, were already reported (32). They were now converted to molal scale by the relationship a (molar) = a (molal) do, where a is activity and do, the density of solvent; do of 0.7865 was used for methanol a t 25" C. Other data were calculated from the literature values for solubilities, as cited in Table 111.…”

Section: 929mentioning

confidence: 59%

Estimation of Medium Effects for Single Ions and Their Role in the Interpretation of Nonaqueous pH.

Popovych¹

1966

Anal. Chem.

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“…pH‐Metric titration was performed on an I‐160 instrument (Gomel Plant of Measuring Equipment, Belarus) at 25±1 °C using 8 m m HCl solution in an H 2 O/EtOH mixture (80 vol %) with an accuracy of ±0.05 log units. The acidities were determined according to a procedure described elsewhere . The concentration of compound 3 d was 2.04 m m , and the initial volume was 10 mL.…”

Section: Methodsmentioning

confidence: 99%

“…The acidities were determined according to aprocedure described elsewhere. [33] The concentration of compound 3d was 2.04 mm,a nd the initial volume was 10 mL. The experimental data were processed with pK a calculation using STALABS software.…”

Section: Methodsmentioning

confidence: 99%

6‐Methyluracil Derivatives as Bifunctional Acetylcholinesterase Inhibitors for the Treatment of Alzheimer's Disease

et al. 2015

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Novel 6-methyluracil derivatives with ω-(substituted benzylethylamino)alkyl chains at the nitrogen atoms of the pyrimidine ring were designed and synthesized. The numbers of methylene groups in the alkyl chains were varied along with the electron-withdrawing substituents on the benzyl rings. The compounds are mixed-type reversible inhibitors of cholinesterases, and some of them show remarkable selectivity for human acetylcholinesterase (hAChE), with inhibitory potency in the nanomolar range, more than 10,000-fold higher than that for human butyrylcholinesterase (hBuChE). Molecular modeling studies indicate that these compounds are bifunctional AChE inhibitors, spanning the enzyme active site gorge and binding to its peripheral anionic site (PAS). In vivo experiments show that the 6-methyluracil derivatives are able to penetrate the blood-brain barrier (BBB), inhibiting brain-tissue AChE. The most potent AChE inhibitor, 3 d (1,3-bis[5-(o-nitrobenzylethylamino)pentyl]-6-methyluracil), was found to improve working memory in scopolamine and transgenic APP/PS1 murine models of Alzheimer's disease, and to significantly decrease the number and area of β-amyloid peptide plaques in the brain.

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Correlation between Apparent pH and Acid or Base Concentration in the ASTM Medium

Cited by 19 publications

References 33 publications

Acid-base behavior in aprotic organic solvents

Acid-base behavior in aprotic organic solvents

Estimation of Medium Effects for Single Ions and Their Role in the Interpretation of Nonaqueous pH.

6‐Methyluracil Derivatives as Bifunctional Acetylcholinesterase Inhibitors for the Treatment of Alzheimer's Disease

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