Title
New alternative to determine the yield of ethylene oxide substitution in hydroxyethyl cellulose reaction by near-infrared spectroscopy and partial least squares regression
Authors
M. M. LOPEZ-TAPIA C. C. LOPEZ-SUERO and R. MARIN-SANCHEZ

Received May 19, 2017
Published Volume 52 Issue 9-10 October-December
Keywords ethylene oxide efficiency, hydroxyethyl cellulose (HEC), molar substitution (MS), near infrared spectroscopy (NIRS), partial least squares (PLS) regression

Abstract
The yield of substitution of ethylene oxide in the hydroxyethyl cellulose reaction is a crucial parameter disclosed by molar substitution and is closely related to the performance of the polymer. A simple, fast and green method for determining the molar substitution of hydroxyethyl cellulose has been developed in this study, using near infrared spectroscopy (NIRS). One of the major advantages of this method is saving time for the quality control procedures in chemical industry – at least 7 hours compared to the reference gas chromatography method. This technique eliminates chemical reactions, the need to manipulate hazardous materials, and minimizes waste generation and energy consumption. NIRS spectra were collected in the range from 5708.26 to 5553.98 cm-1 for samples with molar substitution from 1.18 to 2.14. Partial least squares regression was used, providing a RMSEC (root mean square error of calibration) of 0.00363 and a RMSEP (root mean square error of prediction) of 0.0171.