Dielectric absorption in aliphatic long-chain esters in the solid state

1969 ◽  
Vol 65 ◽  
pp. 1289 ◽  
Author(s):  
R. J. Meakins
Keyword(s):  
Solid State ◽  
Dielectric Absorption ◽  
Long Chain

Temperature Dependence of the Dielectric Properties of Long-Chain Aliphatic Alcohols in the Solid State

1952 ◽  
Vol 5 (4) ◽  
pp. 661 ◽  
Author(s):  
JS Dryden
Keyword(s):  
Dielectric Properties ◽  
Solid State ◽  
Temperature Dependence ◽  
Aliphatic Alcohols ◽  
Experimental Results ◽  
Secondary Alcohols ◽  
Primary Alcohols ◽  
Dielectric Absorption ◽  
Apparent Activation Energies ◽  
Long Chain

The dielectric properties of three primary and three secondary long-chain aliphatic alcohols have been investigated within the temperature range of -20 to 70 �C. The experimental results are discussed in relation to the theory of Sack on dielectric absorption in linear polar chains and to the conclusions reached in earlier papers on the dielectric properties of these compounds. The apparent activation energies in the primary alcohols are approximately three times those in the secondary alcohols. This indicates either different mechanisms of absorption in the two types of alcohols or, if the mechanisms are the same, significant differences in the energy barriers involved.

The Dielectric Properties of Symmetrical Long-Chain Secondary Alcohols in the Solid State

1951 ◽  
Vol 4 (2) ◽  
pp. 213 ◽  
Author(s):  
RL Meakins ◽  
RA Sack
Keyword(s):  
Hydrogen Bonding ◽  
Solid State ◽  
Dielectric Loss ◽  
Low Temperatures ◽  
Room Temperature ◽  
Molecular Chain ◽  
Hydroxyl Groups ◽  
Crystal Formation ◽  
Secondary Alcohols ◽  
Long Chain

Symmetrical long-chain secondary alcohols in the solid state show very high dielectric loss at audio and radio frequencies. This can be explained by the presence of chains of hydroxyl groups linked by hydrogen bonding and capable of reversing their direction. Further evidence of hydrogen bonding is provided by a study of the melting points of the secondary alcohols and related compounds. The amount of dielectric loss depends markedly on the manner of formation of the solid, being smallest for samples formed by recrystallization from solvents at low temperatures and largest for specimens obtained by slow cooling from the melt. The alcohols of molecular chain-lengths of 13, 15,17, and 19 carbon atoms show a considerable decrease of absorption on storing at room temperature. For alcohols of between 23 and 43 carbon atoms the loss is rather smaller with a peak at higher frequencies, but remains more constant in time. These results are interpreted in terms of competing influences of van der Waals forces and hydrogen bonds during crystal formation ; the former, which lead to a structure unsuitable for the formation of hydrogen-bond chains, are predominant at low temperatures, but become more rapidly neutralized by thermal motion, especially for the shorter molecules. The high temperature modification of the lower homologues is unstable at room temperature, and a molecular diffusion process causes the bond chains to break. Dilute systems of secondary alcohols with hydrocarbons or paraffin wax of similar molecular chain-length show very small dielectric loss suggesting a solid solution in which bond chains cannot be formed ; if the paraffin molecules are appreciably longer, the absorption is large and decreases on storing, presumably owing to the presence of a pure alcohol phase. I.

Magnetic Susceptibility Of Binary Mixtures Of Long Chain Molecular Systems In The Solid State

1976 ◽  
Vol 34 (5) ◽  
pp. 127-132 ◽  
Author(s):  
F. J. Baltá-calleja ◽  
H. Ĉcĉković ◽  
R. Hosemann ◽  
J. Loboda-ĉaĉković
Keyword(s):  
Magnetic Susceptibility ◽  
Solid State ◽  
Binary Mixtures ◽  
Molecular Systems ◽  
Long Chain

On the Thermal Behaviour of Long-Chain Lithium and Sodium n.Alkanoates

1977 ◽  
Vol 32 (6) ◽  
pp. 627-631 ◽  
Author(s):  
P. Ferloni ◽  
M. Zangen ◽  
P. Franzosini
Keyword(s):  
Solid State ◽  
Thermal Behaviour ◽  
State Transition ◽  
Dsc Analysis ◽  
Solid State Transition ◽  
Long Chain ◽  
Phase Relationships

Abstract The phase relationships in Li and Na n.alkanoates from octanoate to dodecanoate were investigated by means of DSC analysis. Clearing (when present), fusion, and solid state transition (when possible) temperatures and enthalpies were measured. The collected results are discussed in comparison with literature data, mostly obtained by different techniques.

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