ANALYSIS OF EXTRACTION PRODUCTS AND WATER-ALKALINE HYDROLYSIS OF TECHNICAL BIRCH BARK UNDER THE ACTION OF MICROWAVE EMF

Abstract

Research has been carried out on the separation of betulin and suberin from the debarking waste of the pulpwood of the Arkhangelsk PPM, crushed on an abrasive crusher. The extraction of betulin from various fractions of technical bark was carried out by the method of extraction with 86% ethyl alcohol using microwave EMF (microwave extraction). Suberin was isolated from the extracted bark by hydrolysis with an aqueous solution of KOH also under microwave heating conditions. The maximum yield of betulin and suberin is achieved when using coarse bark fractions (3–4.5 mm), which are crushed birch bark. The resulting products were identified by IRS, NMR, and GC with mass spectrometry (GC/MS). The quantitative content of components in bark extracts was determined by HPLC analysis. The triterpenoid betulinol (70–72%) predominates in the composition of extractives, betulinic acid, lupeol, and erythrodiol are less represented. Fatty, dibasic carboxylic acids and hydroxy acids were identified in the composition of suberin monomers, 2-hydroxydecanedionic (2-hydroxysebacic) acid dominates. The quantitative content of ferulic acid, a natural antioxidant, was determined in the product from different fractions of the bark (from 2.65 to 11.27 g/kg). Suberin obtained from small fractions of the bark differs from suberin from large fractions in composition. Ribofuranose and xylose were found in the product from the 1–2 mm bark fraction, but absent in the product from the 2–3 mm fraction; lanosterol is present in suberin from the small fraction of the bark, cycloartenol from the large one.