首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
The dioxane lignin has been isolated by Pepper's method with a yield of 9.5% on the Komarov lignin from the ripe stems of the sea island cotton plant of variety S-6030. The developed emperical formula has been calculated, the IR and UV spectra have been taken, and the molecular-mass distribution has been studied. The dioxane lignin is polydisperse. Mw=10,100, Mn=5350.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 628–630, September–October, 1983.  相似文献   

2.
Summary 1. Lignin has been isolated from the stems ofPhragmites communus Trin. by the hydrochloric acid and the copperammonia methods. Its elementary composition and functional groups have been determined. The mean composition of the C6-C3 structural unit has been determined.2. The oxidation of comminuted reed stems with nitrobenzene in the presence of alkali has given a mixture of aldehydes: syringaldehyde, vanillin, and p-hydroxybenzaldehyde. Their yield was 3–4 times less than from wood.Khimiya Prirodnykh Soedinenii, Vol. 1, No. 6, pp. 424–427, 1965  相似文献   

3.
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.  相似文献   

4.
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.  相似文献   

5.
A comparative analysis has been made of the dioxane lignins of the stems, seedling shoots, and seed coats of the cotton plant. The ratio of p-hydroxyaromatic, guaiacyl, and syringyl units in the macromolecules of the lignins has been determined, and so have the amounts of functional groups and bonds. It has been established that the main difference between the dioxane lignins from seedling shoots and seed coats of the cotton plant, on the one hand, and the lignin from the woody stems, on the other hand is a lower content of syringyl and guaiacyl units in the former.Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 798–808, November–December, 1994.  相似文献   

6.
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.  相似文献   

7.
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.  相似文献   

8.
Summary The decomposition of the hydrochloric acid lignin of the stems of the cotton plantGossypium hirsutum of variety 108-F by metallic sodium in liquid ammonia gives 3.8% of a mixture of phenols, among which the following were identified by GLC: dihydroeugenol, 4-hydroxy-3-methoxyphenylpropan-1-ol, (4-hydroxy-3-methoxyphenyl)ethane, (4-hydroxy-3,5-dimethoxyphenyl)propane, and 1-(4-hydroxy-3,5-dimethoxyphenyl)ethanol, and also vanillin and vanillyl alcohol.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 646–648, September–October, 1976.  相似文献   

9.
A comparative investigation of the acid hydrolysis of the guza-paya [stems and bolls] and seed husks of the cotton plant has shown that the hydrolysates differ in their quantitative levels of monosaccharides, but in the pentose hydrolysates xylose predominates in both cases. The extracts after the preliminary enrichment of the raw material contain a large amount of xylose. The sulfuric-acid lignin obtained from the guza-paya contains a far smaller amount of unhydrolyzed polysaccharide and a larger amount of functional groups than the lignin from the husks.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 48–52, January–February, 1987.  相似文献   

10.
The action of catalytic amounts of anthraquinone on the alkaline hydrolysis of the stems and dioxane lignin of the cotton plant of the ssp.mexicanium has been investigated. It has been established that this leads to a substantial increase in the yield of low-molecular-weight hydrolysis products. Analysis of the monomeric fractions of the hydrolysis products by the GLC method has shown the presence in them of large amounts of substances with a p-coumaryl structure. This, and also the low level of syringyl derivatives, may be caused by the demethoxylation of the lignin under the conditions described.Institute of the Chemistry of Plant Substances, Academy of Sciences of the USSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 391–395, May–June, 1985.  相似文献   

11.
The composition, stability, and structure of palladium(II) chloride complexes in hydrochloric acid media have been determined using nuclear-magnetic relaxation, magnetochemical methods, and Rayleigh light scattering. The predominant form in solution for palladium(II) concentrations greater than 0.005 moles/liter is the octahedral Pd6Cl12 or Pd6Cl14 2–, which has antiferromagnetic properties in contrast with the paramagnetic properties of the mononuclear aquachloride. The polarizability anisotropy of Pd-Cl bonds with terminal and bridging chlorine atoms has been determined.Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2473–2477, November, 1990.  相似文献   

12.
An N-arylphosphatidylethanolamine has been isolated from the total phospholipids of the cotton plant of variety S-6029. The composition and the position distribution of the fatty-acid radicals has been studied with the aid of enzymatic hydrolysis with phospholipase A1 (from the fungusRhisophus microsporus UzLT-1) and by alkaline and acid hydrolyses. From the results obtained, the possible molecular composition of the N-acylphosphatidylethanolamine has been calculated by Coleman's method. The total number of all the molecular species amounted to 720.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 780–783, November–December, 1979.  相似文献   

13.
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.  相似文献   

14.
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.  相似文献   

15.
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.  相似文献   

16.
Summary 1. The qualitative and quantitative composition of the combined alkaloids from the leaves, stems, seeds, and roots ofAmmothamnus lehmanni Bge. according to its vegetation periods have been studied.2. It has been found that the young plant contains predominantly the N-oxide forms of the matrine alkaloids, and as the plant develops these are reduced to the free bases.3. A new base lehmannine, C15H22ON2 has been isolated for which 12,13-dehydromatrine is proposed as the most probable structure.V. I. Lenin Tashkent State University. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 377–380, May–June, 1975.  相似文献   

17.
Summary From the stems of the cotton plant infected with the fungusVerticillium dahliae Kleb. has been isolated a quinone derivative of hemigossypol — hemigossypolone — for which the structure 8-formyl-6,7-dihydroxy-5-isopropyl-3-methyl-1,4-naphthoquinone is proposed, and its fungitoxicity has been determined.Division of Bioorganic Chemistry of the Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 341–344, May–June, 1977.  相似文献   

18.
Summary 1. The nitration of spruce lignin obtained by mechanical grinding has been carried out with nitric acid in an anhydrous medium under heterogeneous and homogeneous conditions. Fractionation of the nitrolignin has been carried out and the elementary and functional composition of the fractions has been determined; the mean semi-empirical formulas of the C9 structures have been calculated for both fractions. It has been shown that, depending on the nitration conditions, from one to two nitro groups enter the C6-C3 structural element of nitrolignin and, with an excess of HNO3, nitrate groups as well.The fall in the content of OCH3 groups corresponds to the content of phenolic hydroxyl groups in the initial MGL and can be explained by the demethylation of the guaiacyl structures of the lignin on nitration.Khimiya Prirodnykh Soedinenii, Vol. 2, No. 1, pp. 58–65, 1966  相似文献   

19.
The composition of the neutral lipids of leaves of a cotton plant of the wilt-resistant variety 175-F, the set of components in the fatty acid composition of the lipid classes, and the partial structures of the triacylglycerides have been determined. The changes taking place in the composition and structure of these lipids on artificial infection of the plant by the fungal pathogenVerticillium dahliae have been elucidated.Institute of the Chemistry of Plant Substances, Uzbekistan Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 477–483, September–October, 1992.  相似文献   

20.
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.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号