Relationship between free energy and hydrocarbon chain length in the transfer of hydrocarbons and alcohols into aqueous solutions of tetraalkylammonium salts

1982 ◽  
Vol 23 (2) ◽  
pp. 307-309 ◽  
Author(s):  
Yu. A. Mirgorod
Keyword(s):  
Free Energy ◽  
Aqueous Solutions ◽  
Chain Length ◽  
Hydrocarbon Chain ◽  
Tetraalkylammonium Salts ◽  
Hydrocarbon Chain Length

STABILITY OF COLLOIDAL ALUMINA DISPERSION IN AQUEOUS ALKYL SULFATE SOLUTIONS

2007 ◽  
Vol 14 (03) ◽  
pp. 395-401 ◽  
Author(s):  
SHAOXIAN SONG ◽  
YIMIN ZHANG
Keyword(s):  
Aqueous Solutions ◽  
Chain Length ◽  
Hydrocarbon Chain ◽  
Alkyl Sulfate ◽  
Experimental Results ◽  
Sulfate Concentration ◽  
Sulfate Solutions ◽  
Hydrocarbon Chain Length ◽  
Alkyl Sulfates

Coagulation of colloidal alumina in aqueous solutions in the absence or presence of alkyl sulfates has been studied by means of measurements of electrokinetics, adsorption, and coagulate size in this work. The experimental results showed that the coagulation of colloidal alumina in aqueous alkyl sulfate solutions was much stronger than that in aqueous electrolytic solutions. It closely correlated with particle hydrophobicity rendered by the adsorption of alkyl sulfate anions on alumina/water interfaces, indicating hydrophobic coagulation. Also, it has been found that the hydrocarbon chain length of alkyl sulfate strongly influences the hydrophobic coagulation. The longer the chain, the stronger the coagulation and the lower the alkyl sulfate concentration needed for achieving the maximum coagulation degree.

Conductometric study of hydrophobic interactions in aqueous solutions of double long-chain electrolytes

1973 ◽  
Vol 26 (12) ◽  
pp. 2649 ◽  
Author(s):  
DG Oakenfull ◽  
DE Fenwick
Keyword(s):  
Aqueous Solutions ◽  
Chain Length ◽  
Hydrophobic Interaction ◽  
Hydrophobic Interactions ◽  
Ion Pairs ◽  
Hydrocarbon Chain ◽  
Hydrocarbon Chain Length ◽  
Hydrocarbon Chains ◽  
Methylene Groups ◽  
Conductometric Study

We report measurements of the equivalent conductance (Λ) of aqueous solutions of a series of decyl- and hexadecyl-trimethylammonium carboxylates (acetate to undecanoate). In the decyl series, measurements were made on both sides of the critical micelle concentration (CMC). The CMC decreased when the hydrocarbon chain length of the carboxylate ion increased. In the hexadecyl series, measurements were confined to micellar solutions. ��� The results obtained below the CMC suggest that hydrophobic interaction between the hydrocarbon chains of decyltrimethylammonium undecanoate, decanoate, and nonanoate leads to the formation of ion- pairs. There was no evidence, however, for formation of ion-pairs by the shorter carboxylates. ��� By assuming that micellar ions obey the Onsager equation, we have derived a theoretical relationship between Λ and concentration above the CMC. An excellent fit of theoretical curve to experimental points can be obtained by adjusting the value of a single parameter. This parameter is {(m+1)/n}Kmic (where Kmic is the association constant for binding the carboxylate ion to the micelle and m/n is the ratio of tetra-alkylammonium ions to carboxylate ions in the micelle). ��� Plots of -RT ln[{(m+1)/n}Kmic] against the number of methylene groups on the carboxylate ion are linear for both series, which suggests that m/n is independent of the chain length of the carboxylate ion. Both lines have a slope equal to N�methy and Scheraga's estimate of the free energy of hydrophobic interaction between two methylene groups (-1.40 kJ/mol).

scholarly journals Structure and Interdigitation of Chain-Asymmetric Phosphatidylcholines and Milk Sphingomyelin in the Fluid Phase

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1441
Author(s):  
Moritz P. K. Frewein ◽  
Milka Doktorova ◽  
Frederick A. Heberle ◽  
Haden L. Scott ◽  
Enrico F. Semeraro ◽  
...  
Keyword(s):  
Chain Length ◽  
Hydration Shell ◽  
Fluid Phase ◽  
Hydrocarbon Chain ◽  
Specific Model ◽  
Glycerol Backbone ◽  
Membrane Composition ◽  
Membrane Structures ◽  
Hydrocarbon Chain Length ◽  
Dynamics Simulations

We addressed the frequent occurrence of mixed-chain lipids in biological membranes and their impact on membrane structure by studying several chain-asymmetric phosphatidylcholines and the highly asymmetric milk sphingomyelin. Specifically, we report trans-membrane structures of the corresponding fluid lamellar phases using small-angle X-ray and neutron scattering, which were jointly analyzed in terms of a membrane composition-specific model, including a headgroup hydration shell. Focusing on terminal methyl groups at the bilayer center, we found a linear relation between hydrocarbon chain length mismatch and the methyl-overlap for phosphatidylcholines, and a non-negligible impact of the glycerol backbone-tilting, letting the sn1-chain penetrate deeper into the opposing leaflet by half a CH2 group. That is, penetration-depth differences due to the ester-linked hydrocarbons at the glycerol backbone, previously reported for gel phase structures, also extend to the more relevant physiological fluid phase, but are significantly reduced. Moreover, milk sphingomyelin was found to follow the same linear relationship suggesting a similar tilt of the sphingosine backbone. Complementarily performed molecular dynamics simulations revealed that there is always a part of the lipid tails bending back, even if there is a high interdigitation with the opposing chains. The extent of this back-bending was similar to that in chain symmetric bilayers. For both cases of adaptation to chain length mismatch, chain-asymmetry has a large impact on hydrocarbon chain ordering, inducing disorder in the longer of the two hydrocarbons.

scholarly journals Effect of Hydrocarbon Chain Length of Amphiphilic Ruthenium Dyes on Solid-State Dye-Sensitized Photovoltaics

Nano Letters ◽  
2005 ◽  
Vol 5 (7) ◽  
pp. 1315-1320 ◽  
Author(s):  
Lukas Schmidt-Mende ◽  
Jessica E. Kroeze ◽  
James R. Durrant ◽  
Md. K. Nazeeruddin ◽  
Michael Grätzel
Keyword(s):  
Solid State ◽  
Chain Length ◽  
Hydrocarbon Chain ◽  
Dye Sensitized ◽  
Hydrocarbon Chain Length ◽  
Ruthenium Dyes

Cation exchange in synthetic manganates: II. The structure of an alkylammonium-saturated phyllomanganate

Clay Minerals ◽  
1986 ◽  
Vol 21 (5) ◽  
pp. 957-964 ◽  
Author(s):  
E. Paterson ◽  
D.R. Clark ◽  
D. Russell ◽  
R. Swaffield
Keyword(s):  
Chain Length ◽  
Photoelectron Spectroscopy ◽  
Hydrocarbon Chain ◽  
Exchange Capacity ◽  
Basal Spacing ◽  
Water Molecules ◽  
Interlayer Water ◽  
X Ray ◽  
Alkyl Chains ◽  
Hydrocarbon Chain Length

AbstractA synthetic phyllomanganate saturated with a series of primary alkylammonium cations has been examined using XRD, chemical analysis and X-ray photoelectron spectroscopy. A linear relationship exists between the basal spacing of the saturated alkylammonium-manganate and the hydrocarbon chain length in the interlayer, and from the gradient it is concluded that the alkyl chains are perpendicular to the manganate sheet. This orientation is a function of both the charge density and the presence of a layer of water molecules immediately adjacent to the manganate basal surfaces. Evacuation results in the loss of this interlayer water and the structure of the organo-manganate is considerably disrupted. The extent to which the interlayer arrangement can be reinstated by rehydration is dependent on the chain length of the saturating organo-cation. For cations of chain length > C6 the C contents suggest that cation in excess of the exchange capacity is present in the interlayer, but the absence of any compensating anion and the release of amine on evacuation suggests that the excess C arises from the presence of free amine.

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