Viscosities of mixtures of branched and normal alkanes with tetrabutyltin. Effect of the orientational order of long-chain alkanes on the entropy of mixing

1975 ◽  
Vol 79 (18) ◽  
pp. 1970-1974 ◽  
Author(s):  
Genevieve Delmas ◽  
Patricia Purves ◽  
Pierre De Saint-Romain
Keyword(s):  
Orientational Order ◽  
Normal Alkanes ◽  
Entropy Of Mixing ◽  
Long Chain

Excess heat capacities and excess volumes of tetraalkyltin compounds: . Effect of correlations of molecular orientations and steric hindrance. Part 1

1984 ◽  
Vol 62 (6) ◽  
pp. 1008-1015 ◽  
Author(s):  
Bernard Riedl ◽  
Geneviève Delmas
Keyword(s):  
Steric Hindrance ◽  
Central Atom ◽  
Orientational Order ◽  
Excess Volumes ◽  
Pure Liquid ◽  
Flory Theory ◽  
Flow Calorimeter ◽  
Alkyl Chains ◽  
Chain Compounds ◽  
Long Chain

A Picker flow calorimeter has been used to obtain molar excess capacities [Formula: see text] through the concentration range at 25 °C for the systems [Formula: see text] where R is the alkyl group CnH2n+1, (n = 1, 2, 3, 4, 8, 12). Excess volumes have also been measured for the mixtures. Two contributions to [Formula: see text] and vE were investigated: those associated with disordering the long alkyl chains and with steric hindrance. The steric hindrance contribution has been found to occur for molecules having a highly substituted central atom. The sign of this contribution is negative in hE and positive in [Formula: see text], indicative of an ordering or loss of mobility for the molecules going from pure liquid to solution. The [Formula: see text] results confirm the more sterically hindered character of the ethyl and propyl derivatives already found with hE. The separation of the disorder and steric contribution is possible in systems involving long-chain compounds. It is found that the orientational order contribution diminishes more slowly with temperature than the steric hindrance effect. The trend of vE in the series is reasonably well predicted by the Prigogine–Patterson–Flory theory.

Heats of mixing of trialkylamines: disorder and steric hindrance contributions

1978 ◽  
Vol 56 (22) ◽  
pp. 2856-2865 ◽  
Author(s):  
Robert Philippe ◽  
Geneviève Delmas ◽  
Phuong Nguyen Hong
Keyword(s):  
Steric Hindrance ◽  
Significant Contribution ◽  
Orientational Order ◽  
Class A ◽  
Heats Of Mixing ◽  
Class B ◽  
Chain Compounds ◽  
Sterically Hindered ◽  
Long Chain ◽  
Long Chains

Nine trialkylamines, triethyl- to trihexylamine trioctyl-, tridodecyl, tri(methyl-2-butyl)-, and dimethyldodecylamine have been used for heats of mixing of the following systems at 298 K: A, fourteen systems made of all the possible binary mixtures (except one) of the six shorter amines; B, twelve systems made of a long chain amine, trioctyl-, tridodecyl- or dimethyldodecylamine with the four shorter members of the series; C, two systems consisting of the mixture of two long-chain compounds, trioctylamine with tridodecyl- and dimethyldodecylamine. Heats for the class A systems are less than or equal to 40 J/mol, indicating no net effect of the small polarity of the shorter members of the series. The experimental HE of these mixtures are compared with two theories. The Monte Carlo approach gives good predictions but the heats calculated with the Snider–Herrington theory are too negative. Heats of the class B systems are suitable for the investigation of two new contributions to the heats of mixing, the positive heat of disordering of long-chains HE(dis.) and the negative heat found in systems where one of the components is sterically hindered, HE(ster.hindr.). HE(dis.) found with the long-chain amines indicates an orientational order larger than in the case of the n-alkane of the same chain-length but equivalent to that found in the tetraalkyltin compounds of the same length. Recent work has shown that the tetrapropyl and tetraethyltin derivatives when mixed with long-chain alkanes or tin derivatives give rise to a HE(ster.hindr.) contribution. From this work and the present study, the steric hindrance contributions of five sterically hindered compounds tetraethyltin and tetrapropyltin, triethyl- and tripropylamine, and 3,3-diethylpentane mixed with different second components are calculated. The steric hindrance contribution is found proportional to the volume of the second component and increasing in the following order of the sterically hindered component: triethyl- < tripropylamine < tetraethyl- < tetrapropyltin < 3,3-diethylpentane. Heats of the class C systems are small without significant contribution of HE(dis.) due to the fitting of the long-chains in solution.

Estimation of the critical constants of long-chain normal alkanes

1996 ◽  
Vol 17 (2) ◽  
pp. 455-469 ◽  
Author(s):  
E. D. Nikitin ◽  
P. A. Pavlov ◽  
P. V. Skripov
Keyword(s):  
Normal Alkanes ◽  
Long Chain ◽  
Critical Constants

scholarly journals Molecular Motion and Phase Changes in Long Chain Solid Normal Alkanes as Studied by1H and13C NMR

1991 ◽  
Vol 64 (4) ◽  
pp. 1299-1304 ◽  
Author(s):  
Takahiro Ueda ◽  
Sadamu Takeda ◽  
Nobuo Nakamura ◽  
Hideaki Chihara
Keyword(s):  
Molecular Motion ◽  
Phase Changes ◽  
Normal Alkanes ◽  
Long Chain

Morphology of orthorhombic long chain normal alkanes: theory and observations

1992 ◽  
Vol 121 (4) ◽  
pp. 679-696 ◽  
Author(s):  
P. Bennema ◽  
Xiang Yang Liu ◽  
K. Lewtas ◽  
R.D. Tack ◽  
J.J.M. Rijpkema ◽  
...  
Keyword(s):  
Normal Alkanes ◽  
Long Chain

Positronium in Normal Alkanes

2012 ◽  
Vol 733 ◽  
pp. 67-74 ◽  
Author(s):  
Tomasz Goworek ◽  
Bożena Zgardzińska ◽  
Marek Pietrow ◽  
Jan Wawryszczuk
Keyword(s):  
High Pressure ◽  
Liquid Phase ◽  
Porous Structure ◽  
Positron Annihilation ◽  
Binary Mixtures ◽  
Normal Alkanes ◽  
Positron Annihilation Lifetime ◽  
Rotator Phase ◽  
Long Chain

A review of data about positron annihilation lifetime in normal alkanes is presented. It was found that positronium in rigid phase locates in the interlamellar gap, while in the rotator one in free volumes inside lamellae. Interesting effects seem to be: identity of o-Ps lifetime in rotator and liquid phase in long chain alkanes; appearance of “premature” rotator phase in nonadecane with low tricosane admixture, long-term relaxation after the changes of temperature or pressure in some binary mixtures, formation of porous structure at solidification of argon saturated alkane under high pressure.

Solid–liquid equilibria of systems containing pyrene and long chain normal-alkanes

1998 ◽  
Vol 148 (1-2) ◽  
pp. 139-146 ◽  
Author(s):  
R. Mahmoud ◽  
R. Solimando ◽  
M. Rogalski
Keyword(s):  
Normal Alkanes ◽  
Solid Liquid ◽  
Long Chain
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