The reactivity of p-nitrophenyl esters with surfactants in nonaqueous solvents. III. The effect of altering the head-groups of alkylammonium carboxylates dissolved in benzene

1980 ◽  
Vol 33 (4) ◽  
pp. 779 ◽  
Author(s):  
CJ O'Conner ◽  
RE Ramage
Keyword(s):  
Chain Length ◽  
Rate Constant ◽  
Alkyl Chain ◽  
Alkyl Chain Length ◽  
Nonaqueous Solvents ◽  
Bimolecular Rate Constant ◽  
Head Groups

The rate of decomposition of p-nitrophenyl acetate, pnpa, has been measured in benzene solutions of a series of alkylammonium propionates, CH3(CH2),NH3+ -O2CCH2CH3 (where n = 3, 5, 7, 9 or 11), and a series of dodecylammonium carboxylates, CH3(CH2)11NH3+ -O2C(CH2)mCH3 where m = 1, 2, 6 or 7). The micellar rate constant is affected by the alkyl chain length. The bimolecular rate constant is affected by both the chain length and the acidity of the head-groups. The reactivity of longer chain esters with dodecylammonium propionate is markedly less than that of pnpa.

The reactivity of p-nitrophenyl esters with surfactants in apolar solvents. VI. Structural effects on the reaction of p-nitrophenyl acetate with alkanediamine bis(dodecanoate) salts

1983 ◽  
Vol 36 (5) ◽  
pp. 907 ◽  
Author(s):  
CJ O'Conner ◽  
TD Lomax
Keyword(s):  
Chain Length ◽  
Rate Constant ◽  
Structural Effects ◽  
Detergent Concentration ◽  
Bimolecular Rate Constant ◽  
Head Groups

The rate of decomposition of p-nitrophenyl acetate has been measured in benzene solutions of a series of alkane-α,ω-diamine bis(dodecanoate) salts. Me(CH2)10CO2-+NH3(CH2)NH3N+ -O2C(CH2)10ME(n=2-7,9,10,12) The micellar rate constant is affected by the diamine chain length, and the bimolecular rate constant is affected both by the chain length (and whether the number of carbon atoms is even or odd) and by the acidity of the diammonium head groups. The Br�nsted plot is linear but the slope in creases with increasing detergent concentration.

The reactivity of p-nitrophenyl esters with surfactants in nonaqueous solvents. II. The effects of added water in benzene solutions of dodecylammonium propionate, and the reaction in toluene and cyclohexane

1980 ◽  
Vol 33 (4) ◽  
pp. 771 ◽  
Author(s):  
CJ O'Conner ◽  
RE Ramage
Keyword(s):  
Rate Constant ◽  
Rate Equation ◽  
Surfactant Concentration ◽  
Nonaqueous Solvents ◽  
Base Catalysis ◽  
Head Group ◽  
Bimolecular Rate Constant ◽  
General Base ◽  
Head Groups ◽  
Added Water

The rate of decomposition of p-nitrophenyl acetate, pnpa, in benzene containing up to 0.11 mol dm-3 of solubilized water in the presence of dodecylammonium propionate, dap, has been measured at 298 K. Although the micellar rate constant is decreased due to hydration of the head- groups, the bimolecular rate constant due to general acid-general base catalysis from the head-group components of dap is unchanged. There is no evidence to suggest that the substrate undergoes hydrolysis. Changing the solvent to either toluene or cyclohexane increases the micellar rate constant and changes the second term in the rate equation to one which includes the square of the surfactant concentration.

Distribution and reactivity of gallates toward galvinoxyl radicals in SDS micellar solutions — Effect of the alkyl chain length

2011 ◽  
Vol 89 (2) ◽  
pp. 181-185 ◽  
Author(s):  
Raquel Bridi ◽  
Carolina Aliaga ◽  
Alexis Aspée ◽  
Elsa Abuin ◽  
Eduardo Lissi
Keyword(s):  
Chain Length ◽  
Rate Constant ◽  
Apparent Rate Constant ◽  
Alkyl Chain ◽  
Sodium Dodecyl ◽  
Homogeneous Solution ◽  
Reaction Rates ◽  
Alkyl Chain Length ◽  
Micellar Solutions ◽  
Methylene Group

In this work, we have evaluated the reactivity of methyl gallate, propyl gallate, and n-octyl gallate toward galvinoxyl radicals in homogeneous solution (ethanol) and sodium dodecyl sulfate micelles. In ethanol, the rate of galvinoxyl consumption was independent of the gallate’s alkyl chain length. On the other hand, reaction rates in micelles were dependent on the length of the gallate alkyl chain. Measurements of the rate of the reaction at different pH show that, even at pH 7.0, the reaction mainly involves the monodeprotonated anionic form of the gallates. Plots of reaction rates as a function of the surfactant concentration allowed us to evaluate the distribution of the gallates (KGH) and an apparent rate constant defined by the product between the intramicellar rate constant of the anion ([Formula: see text]) and its partition constant ([Formula: see text]). The values of the increment of the apparent rate constant per methylene group in the alkyl chain strongly suggest that intramicellar rate constant values are independent of the alkyl chain length. This points to a similar intramicellar localization of the phenolate moiety in the three gallates considered.

scholarly journals Silver Nanoparticles Stabilized with Phosphorus-Containing Heterocyclic Surfactants: Synthesis, Physico-Chemical Properties, and Biological Activity Determination

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1883
Author(s):  
Martin Pisárčik ◽  
Miloš Lukáč ◽  
Josef Jampílek ◽  
František Bilka ◽  
Andrea Bilková ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Biological Activity ◽  
Zeta Potential ◽  
Chain Length ◽  
Alkyl Chain ◽  
Chemical Properties ◽  
Alkyl Chain Length ◽  
Microbial Pathogens ◽  
Physico Chemical ◽  
Phosphorus Containing

Phosphorus-containing heterocyclic cationic surfactants alkyldimethylphenylphospholium bromides with the alkyl chain length 14 to 18 carbon atoms were used for the stabilization of silver nanodispersions. Zeta potential of silver nanodispersions ranges from +35 to +70 mV, which indicates the formation of stable silver nanoparticles (AgNPs). Long-chain heptadecyl and octadecyl homologs of the surfactants series provided the most intensive stabilizing effect to AgNPs, resulting in high positive zeta potential values and smaller diameter of AgNPs in the range 50–60 nm. A comparison with non-heterocyclic alkyltrimethylphosphonium surfactants of the same alkyl chain length showed better stability and more positive zeta potential values for silver nanodispersions stabilized with heterocyclic phospholium surfactants. Investigations of biological activity of phospholium-capped AgNPs are represented by the studies of antimicrobial activity and cytotoxicity. While cytotoxicity results revealed an increased level of HepG2 cell growth inhibition as compared with the cytotoxicity level of silver-free surfactant solutions, no enhanced antimicrobial action of phospholium-capped AgNPs against microbial pathogens was observed. The comparison of cytotoxicity of AgNPs stabilized with various non-heterocyclic ammonium and phosphonium surfactants shows that AgNPs capped with heterocyclic alkyldimethylphenylphospholium and non-heterocyclic triphenyl-substituted phosphonium surfactants have the highest cytotoxicity among silver nanodispersions stabilized by the series of ammonium and phosphonium surfactants.

scholarly journals Physico-chemical and gel properties of heat-induced pasteurized liquid egg white gel: effect of alkyl chain length of alcohol

2021 ◽  
Vol 24 (1) ◽  
pp. 1229-1243
Author(s):  
Danai Charoensuk ◽  
Robert G. Brannan ◽  
Wilailuk Chaiyasit ◽  
Wanlop Chanasattru
Keyword(s):  
Chain Length ◽  
Alkyl Chain ◽  
Egg White ◽  
Alkyl Chain Length ◽  
Gel Properties ◽  
Gel Effect ◽  
Physico Chemical
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