Dielectric absorption and imperfections in symmetrical secondary alcohols

1967 ◽  
Vol 63 ◽  
pp. 1337 ◽  
Author(s):  
H. K. Welsh
Keyword(s):  
Secondary Alcohols ◽  
Dielectric Absorption

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 a Series of dl-n-Eicosanols

1951 ◽  
Vol 4 (3) ◽  
pp. 359
Author(s):  
RJ Meakins ◽  
HK Welsh
Keyword(s):  
Dielectric Properties ◽  
Low Frequency ◽  
Polar Compounds ◽  
Carbon Chain ◽  
Hydroxyl Groups ◽  
Secondary Alcohols ◽  
Polar Group ◽  
Dielectric Absorption ◽  
Ready Availability ◽  
Long Chain

Initial investigations of the dielectric properties of normal long-chain secondary alcohols were made with the symmetrical compounds because of their ready availability. The properties of long-chain polar compounds are known to vary considerably, however, with the position of the polar group in the carbon chain and it therefore seemed desirable to make dielectric measurements with some unsymmetrical alcohols. The present paper describes such an investigation of a series of dl-n-eicosanols having the hydroxyl groups in the 2-, 4-, 6-, 8-, and 10-positions, respectively. The results for the melted forms show that slight asymmetry, as in the 10-compound, has little effect on the dielectric properties, but with the more unsymmetrical 4-, 6-, and 8-compounds a considerable enhancement of the dielectric absorption is observed. This is accompanied by increased dispersion of the dielectric constant which, for the 8-compound, reaches a low frequency value of 15. Both ε" and ε' decrease during storage at room temperature. Anomalous results are obtained with dl-n-eicosan-2-ol, probably due to the molecules in the crystal lattice being alternately reversed, end-to-end. As with the symmetrical secondary alcohols, the recrystallized forms give comparatively little dielectric absorption.

The Dielectric Properties of Crystalline Long-Chain n-Primary Alcohols at Low Frequencies

1951 ◽  
Vol 4 (3) ◽  
pp. 365
Author(s):  
RJ Meakins ◽  
JW Mulley
Keyword(s):  
Dielectric Properties ◽  
Primary Alcohol ◽  
Dielectric Constants ◽  
Double Layers ◽  
Significant Feature ◽  
Hydroxyl Groups ◽  
Secondary Alcohols ◽  
Primary Alcohols ◽  
Dielectric Absorption ◽  
Long Chain

In a previous paper it was reported that certain crystalline forms of long-chain secondary alcohols show abnormally large dielectric absorption and dispersion of the dielectric constant at audio and radio frequencies. The present paper describes an extension of the investigation to n-primary alcohols and discusses the results in terms of the previously suggested theory of dielectric absorption due to the presence of hydrogen-bonded chains of hydroxyl groups. The most significant feature of the results is that the absorption is larger and occurs at much lower frequencies than for the secondary alcohols. This is considered to be due to the end-to-end arrangement of the molecules in n-primary alcohol crystals, which gives double layers of hydroxyl groups and enables the formation of more extensive hydrogen-bond chains. The dielectric constants at the lowest frequencies are almost as large as those previously reported by Hoffmann and Smyth (1949) for the " waxy " forms of n-primary alcohols. Further aspects described are the changes in dielectric properties during storage, the differences between the melted and recrystallized forms, and the effect of dispersing the molecules in an inert solid solvent. In each of these aspects the observed behaviour is similar to that previously reported for the secondary alcohols.

Application of Dess-Martin oxidation in total synthesis of natural products

2020 ◽  
Vol 17 ◽  
Author(s):  
Majid M. Heravi ◽  
Tayebe Momeni ◽  
Vahideh Zadsirjan ◽  
Leila Mohammadi
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Selective Oxidation ◽  
Secondary Alcohols ◽  
Aldehydes And Ketones

: Dess–Martin periodinane (DMP), is a commercially available chemical, frequently being utilized as a mild oxidative agent for the selective oxidation of primary and secondary alcohols to their corresponding aldehydes and ketones, respectively. DMP shows several merits over other common oxidative agent such as chromium- and DMSO-based oxidants, thus it is habitually employed in the total synthesis of natural products. In this review, we try to underscore the applications of DMP as an effective oxidant in an appropriate step (steps) in the multistep total synthesis of natural products.

Oxidation rates of triterpenoid secondary alcohols with chromic acid

1976 ◽  
Vol 41 (3) ◽  
pp. 770-779 ◽  
Author(s):  
M. R. Nair ◽  
S. Hilgard ◽  
J. Klinot ◽  
K. Waisser ◽  
A. Vystrčil
Keyword(s):  
Chromic Acid ◽  
Secondary Alcohols ◽  
Oxidation Rates

Simple theoretical models of elimination reactions on polar catalysts; Dehydration reactivity of secondary alcohols on acidic and basic catalysts

1985 ◽  
Vol 50 (4) ◽  
pp. 920-929 ◽  
Author(s):  
Jiří Sedláček
Keyword(s):  
Experimental Data ◽  
Quantum Chemical ◽  
Theoretical Models ◽  
Aliphatic Alcohols ◽  
Secondary Alcohols ◽  
Carbonium Ion ◽  
Dehydration Reactions ◽  
Aromatic Alcohols ◽  
Basic Catalysts ◽  
Simple Models

CNDO/2 calculations for simple models of adsorption and dehydration reactions of secondary aliphatic and aromatic alcohols on polar catalysts are presented. The models involve selected stages of elimination mechanisms of various types (E1, E2 and E1cB elimination). Calculated quantum chemical quantities were correlated with reported experimental data. It is shown that reactivities for the series of substituted phenylethanols correlate very well with the ease of carbonium ion formation. In the case of aliphatic alcohols, calculated quantities correlate generally with the reactivities on SiO2 and are in anticorrelation with the reactivities on Al2O3.NaOH.

A Proton‐Responsive Pyridyl(benzamide)‐Functionalized NHC Ligand on Ir Complex for Alkylation of Ketones and Secondary Alcohols

2021 ◽  
Author(s):  
Mandeep Kaur ◽  
Noor U Din Reshi ◽  
Kamaless Patra ◽  
Arindom Bhattacherya ◽  
Sooraj Kunnikuruvan ◽  
...  
Keyword(s):  
Secondary Alcohols
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