Determination of ethylene oxide content inn‐Alcohol ethoxylates by proton nuclear magnetic resonance spectroscopy

Abstract

Proton Fourier transform nuclear magnetic resonance spectral data were collected on n-alcohol ethoxylates and used to calculate the percent ethylene oxide (EO) content of the n-alcohol ethoxylate without an internal or external standard. The accuracy and precision of the method were determined from ten repetitive analyses of hexaethylene glycol mono n-dodecyl ether. The standard deviation was 0.23 wt% EO with a relative standard deviation of 0.40%. The method had a relative error of +0.55% and an absolute error of +0.32% EO.KEY WORDS: Ethylene oxide, n-alcohol ethoxylatc analysis, NMR.

Refractive index-hydrophilic lipophilic balance relationship for alcohol ethoxylates

“…Average ethoxylation degrees (except dodecanol ethoxylates) were calculated from synthesis weight balance. Average ethoxylation degrees of dodecanol ethoxylates were determined by an appropriate NMR technique described by Hammond and Kubik (1994).…”

Determination of alcohol polyether average molar oligomer value/distribution via supercritical fluid chromatography coupled with UV and MS detection

“…Calculation of average molar EO values by 1 H NMR followed the method described by Hammond and Kubik [4]. The 1 H NMR spectrum of each sample (64 scans) was acquired three times.…”

“…Proton NMR spectroscopy yields data for calculation of average molar oligomer values by integration of: (a) the absorbance due to the protons of the repeating ethylene oxide (EO) unit of AEOs; and (b) the terminal methyl protons of the alkyl chain [2][3][4]. A similar calculation can be performed with propylene oxide (PO) groups of APOs.…”

“…A similar calculation can be performed with propylene oxide (PO) groups of APOs. 1 H NMR calculation of average molar oligomer values can, however, be distorted by the presence of poly(ethylene glycol) (PEG) [4] in AEOs. PEG can be produced during the formation of AEOs if water is present during their synthesis.…”