METHOD FOR DETERMINATION OF METHYLCELLULOSE SUBSTITUTION DEGREE BY IR-SPECTROSCOPY Russian patent published in 2017 - IPC G01N21/35 

FIELD: chemistry.

SUBSTANCE: method is developed for determination of methylcellulose substitution degree based on the use of disturbed total internal reflection (DTIR) attachment to IR-spectrometer and not requiring any operations for sample preparation and allowing to work just with substances in solid aggregate state. Samples in the form of powders are investigated by spectrometry in the range of (2700-3500) cm^-1 and substitution degree (X) is calculated using the formula: where is ratio of absorption band intensities of valence vibrations of OH and CH, CH₂-groups in methylcellulose at υ₁=3320 cm^-1 and υ₂=2850 cm^-1; is ratio of absorption band intensities of valence vibrations of OH and CH, CH₂-groups in the initial cellulose at υ₁=3410 cm^-1 and υ₂=2850 cm^-1.

EFFECT: method allows to shorten duration of determination of methylcellulose substitution degree, avoid the use of expensive and toxic reagents and also to select the optimum reagent composition for production of methylcellulose with required substitution degree.

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