In the presence of acidic catalysts based on the Sibunit-4 material the effects of mechanical activation and a lignin impurities on both the reactivity of cellulose and yields of products (monosaccharides and furfurals) being achieved during the hydrolysis of the polysaccharide isolated by hydrotropic cooking of miscanthus, wheat straw, and fruit shells of oats were studied. Activation was shown to significantly increase the reactivity of all substrates and the yields of the target products. Impurities of lignin led to decreasing product yields.