Potentiometric Analysis

LAITINEN, H.A.

doi:10.1016/b978-0-12-395671-2.50007-7

Cited by 3 publications

(3 citation statements)

References 99 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The pK a values for these sulfobetaine compounds were determined from the titration half equivalence point according to the Henderson−Hasselbalch equation. 33 The two remarkable features in Table 2 results are that the excess mass in the sulfobetaine equivalent weights corresponds to tightly bonded water molecules ranging from 4.3 to 8.6 units and that associated with the sulfobetaine moiety has a strong acidity, with the pK a ranging from 3.3 to 3.4. As for the rationale for such properties, a broader review of sulfobetaine research provides interesting insights.…”

Section: ■ Results and Discussionmentioning

confidence: 98%

Sulfobetaine-Siloxanes: A Class of Self-Destructive Surfactants

Snow,

Ananth

2024

Langmuir

View full text Add to dashboard Cite

The hydrolytic susceptibility of sulfobetaine-siloxane surfactants is investigated by comparison of a homologous series in this subclass of surfactants (R-(CH 2 ) 3 N + (Me) 2 (CH 2 ) 3 SO 3 − ; R = (Me 3 SiO) 3 Si-, (Me 3 SiO) 2 Si(Me)-, (Me 2 SiO) 3 -Si(Me)-) with an analogue series of oxyethylene-siloxane surfactants (R-(CH 2 ) 3 (OCH 2 CH 2 ) 10.2 OH; R = (Me 3 SiO) 3 Si-, (Me 3 SiO) 2 Si-(Me)-, (Me 2 SiO) 3 -Si(Me)-). Nuclear magnetic resonance (NMR) monitoring of these surfactants in an aqueous solution shows that the presence of the sulfobetaine head structure greatly enhances the hydrolysis rate of the siloxane tail as compared with oxyethylene-siloxane analogue control experiments. This sulfobetaine effect is confirmed by adding a model compound, (Me) 3 N + (CH 2 ) 3 SO 3 − , to the oxyethylene-siloxane surfactants and observing the large hydrolysis enhancement. Measurements of pH indicate the sulfobetaine presence greatly enhances acidity, but rigorous analysis could discover no source of acid other than the presence of the sulfobetaine structure. Titration measurements confirmed the presence of a tightly bound hydration layer of 4−7 water molecules per sulfobetaine group. It is speculated that the source of acidity may originate from an aqueous exclusion zone nucleated by the hydrated sulfobetaine at the interface of a sulfobetaine-siloxane surfactant bilayer aggregate. Hydrolysis prevention is investigated by addition of a pH 7 phosphate buffer, of an alkyl polyglycoside cosurfactant, and of a combination of both, with a finding of very significant but not complete suppression of the hydrolysis.

show abstract

Section: ■ Results and Discussionmentioning

confidence: 98%

Sulfobetaine-Siloxanes: A Class of Self-Destructive Surfactants

Snow,

Ananth

2024

Langmuir

View full text Add to dashboard Cite

show abstract

“…The pH range for which the approximation of eq 3 holds depends on the numerical values of ' and pK2. The expected variation of pK{ and pK2 with ionic strength can be estimated by relating the apparent constants to the thermodynamic dissociation constants Kx, K2 through the application of the extended Debye-Hückel equation (EDHE) (14). The apparent constants can be expressed in the form (15) PK{ = pK1 + log (7tH2S) -log (7tHS-)…”

Section: Resultsmentioning

confidence: 99%

Determination of total dissolved sulfide in the pH range 7.5 to 11.5 by ion selective electrodes

Guterman¹,

Ben‐Yaakov²,

Abeliovich³

1983

Anal. Chem.

View full text Add to dashboard Cite

“…has the major drawback that low results are obtained as a result of air oxidation of S(IV) during the titration (1,2). Furthermore, a report has addressed the formation of elemental sulfur from the reduction of S(IV) by iodide in acidic medium during a direct titration, which could occur in relatively concentrated SO 2 solutions (> 0.04%) (3).…”

mentioning

confidence: 99%

Coulometric Titrations in Wine Samples: Studies on the Determination of S(IV) and the Formation of Adducts

Lowinsohn

Bertotti

2002

J. Chem. Educ.

View full text Add to dashboard Cite

In this experiment, the sulfite in white wine samples is quantified by coulometric titration with iodine, using a procedure that minimizes errors due to air oxidation. Some aspects of the distinction of S(IV) forms in such matrices are discussed on the basis of the formation of adducts between sulfite and carbonyl compounds present in the wine. The reactivity of these S(IV)-bound compounds toward the reaction with iodine is addressed and the stability of the adducts as the sample pH is changed is discussed.

show abstract

Potentiometric Analysis

Cited by 3 publications

References 99 publications

Sulfobetaine-Siloxanes: A Class of Self-Destructive Surfactants

Sulfobetaine-Siloxanes: A Class of Self-Destructive Surfactants

Determination of total dissolved sulfide in the pH range 7.5 to 11.5 by ion selective electrodes

Coulometric Titrations in Wine Samples: Studies on the Determination of S(IV) and the Formation of Adducts

Contact Info

Product

Resources

About