A study of the dioxane lignins of Althaea nudiflora and A. rosea

Summary 1. The lignin has been isolated from the stems of the cotton plant of a late period of vegetation by the hydrochloric acid method. The elementary composition and functional groups have been determined. The mean composition for a C₆-C₃ structural unit has been determined.2. By the oxidation of a powder of the stems of the cotton plant with nitrobenzene in the presence of alkali it has been established that the hydrochloric acid lignin is more condensed than the DLA.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 648–650, September–October, 1975.     

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.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 501–503, July–August, 1986.     

Study of the lignin of a cotton plant of the variety S-6524

The dioxane lignin (DLA) has been isolated from ripe stems of a cotton plant of the variety S-6524, and its empirical formula and molecular mass have been determined. This DLA differed from the DLA of a cotton plant of variety 108-F by a lower degree of hydroxylation and a higher degree of substitution of the aromatic rings.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, FAX (3712) 62 73 48. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 430–431, May–June, 1994.     

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.     

A study of the lignin of the cotton plant of the subspeciesmexicanium

p-Hydroxybenzoic, vanillic, ferulic, and syringic acids, and also p-hydroxybenzalde-hyde and vanillin, have been found in an ethanol-benzene extract of the stems of cotton plants of the subspeciesmexicanium. The dioxane lignin (DLA) has been isolated by Pepper's method, the semiempirical formula of its phenylpropane structural unit and its molecular-mass distribution have been established, and its UV, IR, and PMR spectra have been recorded. The DLA has a comparatively low molecular mass and a lower degree of polydispersity than the dioxane lignin of the cotton plant of variety Tashkent-1, while the amounts of functional groups in them coincide, with the exception of a lower amount of carboxy groups in the DLA.     

A study of the structure of kenaf lignins by alkaline nitrobenzene oxidation

Summary 1. The nitrobenzene oxidation of the natural lignins of kenaf stems and of DLA fractions has been performed. A study of the oxidation products by gas-liquid chromatography has shown that the kenaf lignins are constructed of three types of structural units: p-coumaryl, guaiacyl, and syringyl, with the latter predominating.2. Among the products of the nitrobenzene oxidation of fractions of kenaf dioxane lignin paper chromatography has shown the presence of dihydrodivanillin, which is a representative of structures with a biphenyl bond.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 641–645, September–October, 1978.     

Investigation of the dihydroxylignin ofAlthaea rhyticarpa

Summary 1. The developed semiempirical formula for the dioxane lignin from the stems ofAlthaea rhyticarpa has been found from the results of elementary and functional analyses.2. It has been shown that the lignin consists of high- and low-molecular-weight fractions.3. It has been shown by the nitrobenzene oxidation method that p-coumaryl, guaiacyl, and syringyl structural units are present in the lignin.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 242–246, March–April, 1976.     

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.     

Phospholipids of the cotton plant of variety S-6030

Summary 1. The decomposition of sphagnum moss and of an isolated preparation of lignin (DLA) by means of metallic sodium in liquid ammonia has been performed, and a phenolic fraction has been isolated with a yield of 0.89% from the moss and 10.2% from the lignin.2. The following phenols were isolated from the phenolic fraction and their yields were determined by paper and gas-liquid chromatography: 4-hydroxyphenylpropane, 1-and 3-(4-hydroxyphenyl)propan-1-ols, 1-(4-hydroxy-3-methoxyphenyl)propane, 1-(4-hydroxy-3-methoxyphenyl)-propan-1-ol, p-hydroxybenzaldehyde, vanillin, and p-hydroxybenzyl and vanillyl alcohols.3. The quantitative figures on the composition of the phenolic fraction of the decomposition products give grounds for assuming that the uncondensed structural fragments of sphagnum moss lignin are composed to the extent of two thirds of structural units of the p-hydroxyphenyl type joined to one another by -alkyl aryl ether bonds.4. Weighty evidence is given in favor of the assumption that sphagnum moss lignin contains as monomeric structural fragments vanillin and p-hydroxybenzaldehyde, these being attached to the polymer chain by alkyl-aryl or aryl-aryl ether bonds.S. M. Kirov Belorussian Technologic Institute. Institute of Physical Organic Chemistry, Academy of Sciences of the Belorussian SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 77–83, January–February, 1975.     

Lignin of the fine-fibered cotton plant of variety S-6030 affected by fusarial wilt. II

A comparative study of the products of cleavage by sodium in liquid ammonia of the dioxane lignins (DLAs) from healthy and fusarial-wilt-affected stems of the fine-fibered cotton plant of variety S-6030 and a study of the PMR spectra of both lignins has shown that the DLA from the healthy stems is more highly condensed than the DLA of the stems affected by wilt. The main structures of DNA wilt are of the guaiacyl type. In the DLA from the affected stems, the amount of p-coumaryl structures had increased, which confirms the demethylating action of fusarial wilt on cotton-plant lignin.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 364–366, May–June, 1986.     

Cotton plant lignins

This paper generalizes the results of studies on lignins isolated from the stems, bolls, and seed hulls of cotton plants of a number of varieties as functions of the vegetation periods of the plants. The UV, IR and¹H and¹³C NMR spectra of the lignins have been studied. The dioxane lignin (DLA) and the natural lignins have been subjected to nitrobenzene oxidation and to cleavage with sodium in liquid nitrogen. A structure of the lignin macromolecules consisting of 18 phenylpropane structural units has been done up. Information is given on the use of lignins in agriculture, the food industry, and the paint and varnish industry. The anticorrosion and sorption properties of hydrolysis and modified hydrolysis lignins have been studied.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 40 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 465–496, July–August, 1997.     

Structure of the lignin of cotton plants of the subspeciesmexicanium

The nitrobenzene oxidation and cleavage with metallic sodium and liquid ammonia and with thioacetic acid (TAA) of the natural lignin of cotton plants of the subspeciesmexicanium and of the dioxane lignin (DLA) isolated from it have been performed. A comparison of the yields of the products and their compositions has shown that the most complete and reliable results are given by cleavage with TAA, under which a considerable part of the lignin suffers destruction. The high content of monomeric and dimeric fractions in the products of TAA cleavage shows a low degree of condensation of the lignin of cotton plants of the subspeciesmexicanium.     

Study of the fractional composition of the dioxane lignin from the cotton plant

Summary 1. The dioxane lignin of ripe cotton-plant stems has been separated into six fractions of different molecular weights which were fairly homogeneous and differed considerably in their molecular weights.2. It follows from the semiempirical formulas that in all the fractions guaiacyl structural units predominated. The chemical nonidentity of the fractions is shown by the different amounts of functional groups in the phenylpropane structural units and by the relative optical densities of the main bands in the IR spectra of the fractions.3. The low-molecular-weight fraction differed markedly from the others by a higher content of carbohydrates bound to the lignin and by a greater degree of oxidation.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 69–74, January–February, 1979.     

Change in the structural elements of cotton-plant lignins in the various vegetation periods

Summary 1. The dioxane lignins of the cottonplant of various vegetation periods have been studied, and it has been shown that the lignin changes in the course of the development of the plant: the amount of methoxy groups increases and the amount of phenolic hydroxy groups decreases.2. Gel chromatography of the lignins has shown that they are all polydisperse with a predominance of the high-molecular-weight fraction.3. The 3,4-diethoxybenzaldehyde detected in the products of the alkaline nitrobenzene oxidation of dioxane lignin of the early vegetation period after its ethylation with diethyl sulfate is a direct proof of the presence of catechol structural units in cotton-plant lignin.4. A quantitative determination of the catechol structures in the lignins of the cottonplant has shown that their amount decreases as the plant develops.5. By decomposing the lignins with sodium and liquid ammonia, the presence in them of guaiacyl, syringyl, and p-coumaryl structural units has been confirmed and it has been shown that the lignin becomes less condensed as the plant grows, which is apparently connected with an increase in the degree of its methoxylation.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 100–107, January–February, 1977.     

Dioxane lignin from shoots of the cotton plant of variety 108-F. I

The dioxane lignin has been isolated by Pepper's method from two-week shoots of the cotton plant of variety 108-F and has been separated into two fractions — insoluble and soluble in ether — DLA-A and DLA-B, respectively. It has been shown that in the early stage of development of the cotton plant a low-molecular-weight lignin with a low degree of methoxylation and distinctly different from the lignin from ripe stems of the same cotton plant is synthesized.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 96–98, January–February, 1984.     

An investigation of the lignins of healthy and wilt-affected cotton plants of variety Tashkent-1 according to the vegetation periods

Summary 1. The dioxane lignins of healthy and wilt-affected cotton plants of variety Tashkent-1 have been isolated and have been studied comparatively in relation to the vegetation period. On the basis of elementary and functional analysis, semiempirical formulas of the dioxane lignins isolated (DLCT-I to -VII) have been determined and it has been established that the dioxane lignins isolated from the wilt-affected plants contain more OCH₃ groups per phenyl-propane structural unit than the lignins of healthy plants.2. The molecular-weight distributions of the dioxane lignins have been studied and it has been shown that all the dioxane lignins isolated are polydisperse, those of the affected plants to a greater degree.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 260–264, March–April, 1978.     

A comparative study of the dioxane lignins ofAlthea

Summary 1. The dioxane lignins have been extracted from three species ofAlthea for the first time. On the basis of elementary and functional analyses, the semiempirical formulas of the phenylpropane structural units have been calculated.2. The molecular weight distributions have shown that the DLAs of these species ofAlthea are polydisperse, and in the case of the DLAs of the wild-growing species —A. rhyticarpa andA. nudiflora — the high-molecular weight fraction is predominant, while for the DLA ofA. rosea the low-molecular-weight fraction is predominant.3. In a study of the products of nitrobenzene oxidation it has been established that the DLA of all three species ofAlthea includes p-coumaryl, guaiacyl, and syringyl structural units.4. In the products of decomposition with metallic sodium in liquid ammonia 18 phenols have been identified the structures of which show the presence in the initial lignins of guaiacyl- and syringylpropane units with free OH groups in the side chains in the - and -positions to the aromatic nucleus.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 93–100, January–February, 1977.     

Cleavage by sodium in liquid ammonia of kenaf lignins and the biological activity of the cleavage products

The natural lignin of kenaf stems and fractions of the dioxane lignin of kenaf stems isolated previously were cleaved by sodium in liquid ammonia in order to study their structure. It was established that the kenaf lignins consist of three types of structural units: p-coumaryl, guaiacyl, and syringyl, with a predominance of the guaiacyl types. An antioxidation activity of the monomeric products of the degradation of the kenaf lignins has been found.Institute of the Chemistry of Plant Substances of the Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 738–742, September–October, 1987.     

The lignin of the sea island cotton plant of variety S-6030 affected by fusarial wilt. I

A comparative study of the dioxane lignins isolated from healthy and wilt-affected cotton plant stems has shown thatFusarium fungi demethylate lignin and make it more oxidized than the lignin from healthy stems.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 825–827, November–December, 1985.     

Study of the lignin of cotton plants of the variety AN Bayaut-2. I

The dioxane lignin has been isolated from ripe stems of a cotton plant of the variety AN Bayaut-2. Its developed empirical formula has been derived, its UV, IR, and PMR spectra have been recorded, and its molecular weight has been determined. It has been shown that the dioxane lignins of the stems of cotton plants of different varieties differ in chemical structure.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 101–104, January–February, 1986.