A study of the dioxane lignin of Ricinus communis

The dioxane lignin (DLA) isolated from a powder of the stems the castor-oil plant by a modification of Pepper's method has been investigated. The yield of DLA amounted to 19.85% on the Komarov lignin. On the basis of elementary and functional analysis, a developed semiempirical formula has been proposed for it from which it can be seen that the amounts of methoxy, aliphatic hydroxy, and carbonyl groups are high and that of phenolic hydroxyl low. UV, IR, and PMR spectra have been taken, and the molecular weight of the material has been determined.     

Lipids of Ricinus communis Seeds

Lipids of Kazachok castor seeds were studied. The compositions of neutral lipids of the benzine extract and of the fatty acids of neutral and polar lipids were found. The principal acids were palmitic, oleic, linoleic, and 12-hydroxyoctadec-9-enoic.     

Fractional composition of kenaf dioxane lignin

The fractionation of kenaf dioxane lignin according to molecular weights has been carried out. The six fractions obtained differ by their molecular masses and chemical compositions. Semiempirical formulas of all the fractions have been deduced. The relative optical densities have been calculated on the basis of the IR spectra of the fractions.Institute of the Chemistry of Plant Substances of the Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 641–645, September–October, 1981.     

Fractional composition of kenaf dioxane lignin

The fractionation of kenaf dioxane lignin according to molecular weights has been carried out. The six fractions obtained differ by their molecular masses and chemical compositions. Semiempirical formulas of all the fractions have been deduced. The relative optical densities have been calculated on the basis of the IR spectra of the fractions.     

Investigation of the dioxane lignin of the cotton plant

Summary 1. The dioxane lignins of the stems of cotton plants in the early vegetation period, DLA-I, and in the flowering period, DLA-II, have been investigated. Their developed semiempirical formulas have been established by elementary and functional-group analyses.2. The amounts of catechol structural units in cotton-plant dioxane lignins have been determined for the first time.3. The molecular-weight distribution of the dioxane lignins has been studied and it has been shown that they have high molecular weights (22,000–23,500).Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 80–83, January–February, 1976.     

A study of the dioxane lignin of the stems of the cotton plant of variety S-4880

The dioxane lignin (DLA) has been isolated from the ripe stems of a cotton plant of the variety S-4880 B by a modification of Pepper's method. The yield was 16.9% on the Komarov lignin. The semiempirical formula of a phenylpropane structural unit has been calculated on the basis of elementary and functional analyses. It has been established that the amount of the main functional groups in the DLA and in the lignins isolated from the varieties of 108-F and Tashkent-2 basically coincide, but the DLA investigated was appreciably more highly methoxylated. The IR, UV, and PMR spectra of the DLA have been taken. The molecular-weight distribution of the DLA has been investigated and it has been shown that is is poly-disperse and has a weight-average molecular weight of 7400. Nitrobenzene oxidation and cleavage with sodium and liquid ammonia of the isolated DLA has shown that guaiacyl structural units predominate in it.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 430–434, May–June, 1987.     

Cleavage of the natural lignin and the dioxane lignin of kenaf by thioacetic acid

The dioxane lignin and the natural lignin of kenaf undergo 37.62% and 94.6% cleavage, respectively. The combined monomeric degradation products have been studied by the GLC method. The presence of substances relating to three types of structural units has been established: p-coumaryl, gualacyl, and syringyl. It has been shown by chromatography on Sephadex LH-20 (with ethanol-water (9:1) as solvent and eluent) that the phenolic products of degradation extracted by ethyl acetate at pH 2 consist of five fractions: oligomers, tetramers, trimers, dimers, and monomers.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 234–235, March–April, 1986.     

A study of dioxane lignin from bolls of the cotton plant of variety AN Bayaut-2 II

The dioxane lignin was isolated from ripe bolls of a medium-fiber cotton plant of the variety AN Bayaut-2. Its developed empirical formula was derived, its UV, IR, and PMR spectra were recorded, and its molecular weight was determined. It was shown that the boll lignin is more condensed than the stem lignin. It differs from the stem lignin by a lower content of methoxy groups and a higher content of hydroxy and carbonyl groups.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 428–429, May–June, 1987.     

An investigation of the dioxane lignin of cotton bolls

Summary 1. Dioxane lignin has been isolated from mature stems of the cotton plantGossypium hirsutum by mild acidolysis in an atmosphere of nitrogen.2. Its expanded semiempirical formula has been established by elementary and functional analyses.3. The molecular-weight distribution of the dioxane lignin has shown that it consists of high-molecular-weight and low-molecular-weight fractions.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 645–648, September–October, 1974.     

Nitrobenzene oxidation of fractions of cotton-plant dioxane lignin

Summary Analysis of the products of alkaline nitrobenzene oxidation of lignin fractions has confirmed their chemical inhomogeneity and has shown that in the various fractions the amounts of condensed syringly and guaiacyl structures differed markedly.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii No. 1, pp. 82–84, January–February, 1979.     

Isolation of individual fractions of dioxane lignin from kenaf stems and their study

Summary 1. Three fractions of dioxane lignin have been isolated from kenaf stems of the variety Uzbekskii-15-74 by stepwise extraction with aqueous dioxane containing HCl.2. On the basis of the results of elementary and functional analyses, semiempirical formulas of all the fractions have been derived, and their IR and UV spectra have been recorded.3. It has been shown that an increase in the time of extraction leads to a rise in the molecular weight of the fractions and to a decrease in their degree of polydispersity.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 637–641, September–October, 1978.