Skip to Content
Merck
  • Measuring the relative hydrogen-bonding strengths of alcohols in aprotic organic solvents.

Measuring the relative hydrogen-bonding strengths of alcohols in aprotic organic solvents.

Chemphyschem : a European journal of chemical physics and physical chemistry (2014-11-25)
Malcolm E Tessensohn, Melvyn Lee, Hajime Hirao, Richard D Webster
ABSTRACT

Voltammetric experiments with 9,10-anthraquinone and 1,4-benzoquinone performed under controlled moisture conditions indicate that the hydrogen-bond strengths of alcohols in aprotic organic solvents can be differentiated by the electrochemical parameter ΔEp (red) =|Ep (red(1)) -Ep (red(2)) |, which is the potential separation between the two one-electron reduction processes. This electrochemical parameter is inversely related to the strength of the interactions and can be used to differentiate between primary, secondary, tertiary alcohols, and even diols, as it is sensitive to both their steric and electronic properties. The results are highly reproducible across two solvents with substantially different hydrogen-bonding properties (CH3 CN and CH2 Cl2 ) and are supported by density functional theory calculations. This indicates that the numerous solvent-alcohol interactions are less significant than the quinone-alcohol hydrogen-bonding interactions. The utility of ΔEp (red) was illustrated by comparisons between 1) 3,3,3-trifluoro-n-propanol and 1,3-difluoroisopropanol and 2) ethylene glycol and 2,2,2-trifluoroethanol.

MATERIALS
Product Number
Brand
Product Description

Supelco
2-Propanol, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
Dichloromethane, anhydrous, ≥99.8%, contains 40-150 ppm amylene as stabilizer
Sigma-Aldrich
1,4-Butanediol, ReagentPlus®, 99%
Sigma-Aldrich
Ethyl alcohol, Pure, 190 proof, ACS spectrophotometric grade, 95.0%
Sigma-Aldrich
Acetonitrile, electronic grade, 99.999% trace metals basis
Sigma-Aldrich
Ethylene glycol 5 M solution
Sigma-Aldrich
Methanol solution, NMR reference standard, 4% in methanol-d4 (99.8 atom % D), NMR tube size 3 mm × 8 in.
Sigma-Aldrich
2-Propanol, BioUltra, for molecular biology, ≥99.5% (GC)
Supelco
Dichloromethane, Selectophore, for ion-selective electrodes, ≥99.5%
Sigma-Aldrich
2-Propanol, BioReagent, for molecular biology, ≥99.5%
Sigma-Aldrich
Ethanol, for residue analysis
Sigma-Aldrich
2-Propanol, HPLC Plus, for HPLC, GC, and residue analysis, 99.9%, poly coated bottles
Sigma-Aldrich
Ethanol, BioUltra, for molecular biology, ≥99.8%, (absolute alcohol, without additive, A15 o1)
Sigma-Aldrich
Ethyl alcohol, Pure 200 proof, for molecular biology
Sigma-Aldrich
2-Propanol, HPLC Plus, for HPLC, GC, and residue analysis, 99.9%
Sigma-Aldrich
Dichloromethane, HPLC Plus, for HPLC, GC, and residue analysis, ≥99.9%, contains 50-150 ppm amylene as stabilizer
USP
2-Propanol, United States Pharmacopeia (USP) Reference Standard
USP
Methyl alcohol, United States Pharmacopeia (USP) Reference Standard
USP
Residual Solvent Class 2 - Acetonitrile, United States Pharmacopeia (USP) Reference Standard
Sigma-Aldrich
tert-Butanol, ACS reagent, ≥99.0%
Sigma-Aldrich
tert-Butanol, ≥99% (GC)
Sigma-Aldrich
1,3-Propanediol, 98%
Supelco
Methylene Chloride, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
Ethanol, tested according to Ph. Eur.
Sigma-Aldrich
Butyl alcohol, natural, ≥99.5%, FCC, FG
Sigma-Aldrich
Tri(2-furyl)phosphine, 99%
Sigma-Aldrich
tert-Butanol, TEBOL® 99, ≥99.3%
Supelco
tert-Butanol, analytical standard
Supelco
Acetonitrile, analytical standard
Sigma-Aldrich
Acetonitrile, ACS reagent, ≥99.5%