Transport properties of a long-chain molecule with side groups capable of molecular orientation. Diffusion of triolein in n-alkanes at 25.degree.C

1981 ◽  
Vol 26 (3) ◽  
pp. 241-242 ◽  
Author(s):  
Thomas C. Amu
Keyword(s):  
Transport Properties ◽  
Molecular Orientation ◽  
Chain Molecule ◽  
Long Chain

scholarly journals Reaction Kinetics of a Long Chain Molecule

1965 ◽  
Vol 5 (5) ◽  
pp. 245-255
Author(s):  
Masahiro TANAKA ◽  
Nanako INOUE ◽  
Ei TERAMOTO
Keyword(s):  
Reaction Kinetics ◽  
Chain Molecule ◽  
Kinetics Of ◽  
Long Chain

scholarly journals Orientation in films of long-chain esters

1937 ◽  
Vol 161 (904) ◽  
pp. 115-127 ◽  
Keyword(s):  
Palmitic Acid ◽  
Molecular Orientation ◽  
Alkyl Chain ◽  
Alkaline Solutions ◽  
Rate Of Hydrolysis ◽  
Long Chain

Monolayers of long-chain fats and esters present some interesting features in molecular orientation, particularly as regards the effect of this orientation on the rate of hydrolysis when spread on alkaline solutions. The dibasic and tribasic long-chain esters (e.g. glycol dipalmitate and tripalmitin) orientate themselves in the interface, with their chains adjacent to one another. The monobasic esters of palmitic acid, however, as Adam (1929) has shown, behave somewhat differently, in that the alkyl chain, if shorter than five carbon atoms and lying extended on the surface in the expanded state, can on compression be forced under the surface into a vertically orientated position opposing the long acidic chain.

Effects of Long-chain Molecule Additives in Water on Vortex Streets

Nature ◽  
1966 ◽  
Vol 211 (5045) ◽  
pp. 169-170 ◽  
Author(s):  
G. E. GADD
Keyword(s):  
Chain Molecule ◽  
Vortex Streets ◽  
Long Chain

THE VISCOSITY – MOLECULAR WEIGHT RELATION FOR POLY-levo-2,3-BUTANEDIYL o-PHTHALATE

1948 ◽  
Vol 26b (12) ◽  
pp. 783-797
Author(s):  
R. W. Watson ◽  
N. H. Grace
Keyword(s):  
Molecular Weight ◽  
High Purity ◽  
Molecular Orientation ◽  
Degree Of Polymerization ◽  
Solution Viscosity ◽  
Dilute Solution ◽  
Molecular Weights ◽  
Complex Relation ◽  
End Group ◽  
Long Chain

The inherent viscosities of dilute solutions of acidic polyesters of high purity have been compared with number average molecular weights accurately determined by end-group titration. For unfractionated resins with a degree of polymerization from 2 to 11 [Formula: see text] the viscosity – molecular weight relation is linear in chloroform at 25 °C. Where [Formula: see text], K = 1.923 × 10−5 and β = 0.0176. For fractionated polyesters from DP 5 to 8, K = 1.959 × 10−6 and β = 0.0161. For unfractionated resins with a DP > 11, molecular weights increase more rapidly than inherent viscosities. Above [Formula: see text] for fractionated resins linearity is resumed, and the slope increases. Several attempts have been made to explain this complex relation. Apparently the short chains remain linear, and the formation of anisotropic fibers at a DP close to 100 establishes a degree of molecular orientation in the long-chain superpolyesters. Isomerization of levo-diol to the diastereoisomer during polycondensation is without effect on the dilute solution viscosity of the resulting resin. Preferential degradation of the longer chains is assumed to be partially responsible for the decreasing slope from DP 11 to 65. As yet it has not been possible to assess the roles played by changes in size distribution, and variation in solvation with increasing chain length, but the data point to a curved viscosity – molecular weight relation in chloroform at 25 °C.

Good-and bad-solvent effect on the rotational statistics of a long chain molecule

1998 ◽  
Vol 8 (1-2) ◽  
pp. 209-218 ◽  
Author(s):  
Giuseppe Allegra ◽  
Fabio Ganazzoli ◽  
Sergio Bontempelli
Keyword(s):  
Solvent Effect ◽  
Chain Molecule ◽  
Long Chain

Molecular orientation in physical-vapour deposition of long-chain stearic acid

1984 ◽  
Vol 69 (2-3) ◽  
pp. 231-240 ◽  
Author(s):  
F. Matsuzaki ◽  
K. Inaoka ◽  
M. Okada ◽  
K. Sato
Keyword(s):  
Stearic Acid ◽  
Molecular Orientation ◽  
Vapour Deposition ◽  
Physical Vapour Deposition ◽  
Long Chain

scholarly journals The torsional flexibility of aliphatic chain molecules

1940 ◽  
Vol 174 (956) ◽  
pp. 137-144 ◽  
Keyword(s):  
Room Temperature ◽  
Threshold Energy ◽  
Chain Molecule ◽  
Aliphatic Chain ◽  
Chain Molecules ◽  
Distortion Effect ◽  
A Chain ◽  
Single Bonds ◽  
Long Chain ◽  
Made In

The rotation of the CH 3 groups round the single C—C bond in ethane is associated with a threshold energy of about 3000 gcal./gmol. or 2 x 10 -13 erg/mol. (Schäfer 1938; Kistiakowsky, Lacher and Strutt 1939). In an aliphatic CH 2 chain where the carbon atoms are linked together by single bonds the corresponding energy must be of the same order and is most likely rather smaller. Supposing we consider any particular C—C bond in the chain and treat the two parts at each side of this bond as rigid rotators, then their kinetic energy would be 2 x 1/2 kT which at room temperature amounts to about one-fifth of the threshold energy. It seems very likely under these circumstances that a chain molecule of say ten to twenty carbon atoms should already at room temperature show signs of distortion due to internal rotation. If this is true, then the previously observed increase of the crystal symmetry at the melting-point of paraffins (Müller 1930, 1932) and the corresponding changes of the polarization of long-chain ketones (Müller 1937, 1938) can no longer be ascribed entirely to a rotation of the molecule in the field of the surrounding molecules but must at least partly be due to this internal distortion. It is clear that a distortion of this type tends to destroy the anisotropy of the molecule and to give an apparent isotropy to the crystal. The present experiments were made in order to obtain an estimate of the magnitude of the distortion effect. It is found to be surprisingly large.

Sign in / Sign up

Export Citation Format

Share Document