A comparison of the surface properties of lignin and sulfonated lignins by FTIR spectroscopy and wicking technique

The comparison of the FTIR spectra indicated that the sulfonation without caused changes in the main structure of lignin and only in the lignin chains. The surface properties, e.g. the surface free energy and related components, e.g. the Lifshitz–van der Waals and Lewis acid–base interactions components, of lignin and lignosulfonates, LGSs, with different ions, e.g. Na⁺–, Mg²⁺–, and Ca²⁺–, studied and compared by wicking technique indicated that the surface free energy of lignin is lower than that of all used LGSs. This suggests that the sulfonation can enhance the surface property for lignin by increasing of the Lifshitz–van der Waals component and Lewis base component of lignin.     

Radiolysis of iodotyrosines in aqueous-ethanol solutions

⁶⁰Co-gamma radiolysis of 3-iodotyrosine and 3,5-diiodotyrosine in aqueous-ethanol solutions has shown that the chemical effects are mainly determined by the interaction of radicals from the radiolysis of solvent and controlled by the composition of the solution. The influence of varying solvent composition and radiation dose on the amount of iodoamino acid converted and on the yields of the radiolysis products (I₂, I^–, IO ₃ ^– and H₂O₂) formed in aerated solutions at room termperature were investigated. The formation of I₂ is dependent upon the acidity of the solution and is mainly produced as an after-effect due to the interaction of H₂O₂ with I^– ions, both being radiolysis products. The variation of radiation-chemical yields with the solute and solvent composition, and the probable mechanisms for formation of the radiolysis products are discussed.     

Ammonolysis of technical lignins

The oxidative ammonolysis of hydrolysis lignin, cellolignin, and lignosulfonate takes place effectively with the greatest formation of a water-soluble fraction at 140–150°C in 2 h. On oxyammonolysis, cellolignin forms approximately twice as much water-soluble fraction as hydrolysis lignin, while lignosulfate desulfonates under conditions exceeding the optimum. The maximum amount of nitrogen in the water-soluble fraction of lignin (nitrogen-containing lignin) amounts to 9.0% for cellolignin and is 2–3% less for the others.M. V. Frunze Simferopol' State University. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 275–278, March–April, 1987.     

Pulse radiolysis studies on [Fe(CN)6]4−−BrO 3 − −CN− system in ethylene glycol — Water solutions

Formation of oxidizing and reducing radicals has been studied by pulse radiolysis of [Fe(CN)₆]^4––BrO ₃ ^– –CN^– system in ethylene glycol — water solvent mixture. Oxidizing ·BrO₂ and BrO radicals formed by electron scavenging with ·BrO ₃ ^– were identified and their reactions were investigated. The reaction of hydroxyl radicals with ethylene glycol leads to formation of reactive radicals with reducing properties and of compounds which reduce slowly in dark the ferricyanide formed in the reaction of ·BrO₂ radical with ferrocyanide.     

Highly hydrophobic sisal chemithermomechanical pulp (CTMP) paper by fluorotrimethylsilane plasma treatment

Fluorinated thin layers were created on chemithermomechanical pulp (CTMP) sisal paper surfaces with fluorotrimethylsilane (FTMS) radio frequency-plasma conditions. It was found that the FTMS-discharge environments caused implantation of fluorine and –Si(CH₃) _x groups into the surface layers of the paper substrates. Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy and Electron Spectroscopy for Chemical Analysis, as well as Atomic Force Microscopy and Scanning Electron Microscopy analyses revealed a smooth surface for the FTMS plasma-treated paper, apparently covered completely with a cross-linked polymerized network. Although the plasma reaction takes place with the cellulose, hemicelluloses and lignin, it appears that the chemical linkage is mainly to the lignin component on the CTMP paper surface by means of mainly C–O–Si–F, with some C–Si–F structures. The CTMP fibers apparently have a high lignin surface concentration. The water absorption for the plasma-treated CTMP paper was reduced from greater than 300 to 17 g of water/m² and the contact angle increased from less than 15° to greater than 120° the strength properties were only slightly reduced and the brightness was essentially unaffected with the FTMS plasma treatment.     

Reductive cleavage by metallic sodium in liquid ammonia of cotton lignin

Twofold cleavage with sodium in liquid ammonia of the dioxane lignin and fourfold cleavage of the native lignin from cotton stems have shown that the uncleaved parts of lignin have molecular masses 2–4 times lower than the initial lignins and consist of 15–17 phenylpropane structural units.Institute of the Chemistry of Plant Substances, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 412–416, May–June, 1989.     

Cleavage of dioxane lignin of the cotton plant with thioacetic acid

Summary 1. It has been established that the dioxane lignin of mature cotton-plant stems is cleaved by thioacetic acid. About 3/4 of the bonds in the lignin are alkyl-aryl ether bonds and only 1/4 are C-C bonds.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 505–507, July–August, 1978.     

Study of the IR spectra of the products of the ethanolysis of oak and pine lignins

Summary The IR spectra of a number of compounds formed in the ethanolysis of the lignin of foliate and coniferous species have been studied using samples of ethanol lignin, vanillin, syringic aldehyde, p-hydroxybenzaldehyde, guaiacylacetone, coniferyl and sinapic aldehydes, vanilloyl methyl ketone, -hydroxypropiovanillone, -ethoxypropiosyringone, and vanillic and gallic acids. Differences in the absorption at 1330–1340 cm^–1 have been found in the spectra of samples of ethanol lignin from oak and pine. Oak lignin has a strong maximum which is absent in pine lignin. Thus, the lignins of foliate and confierous species can be distinguished by the absorption in the spectral region from 1330 to 1340 cm^–1.Khimiya Prirodnykh Soedinenii, Vol. 3, No. 2, pp. 208–213, 1967     

Hydrogenolysis of Willst?tter lignin

Summary 1. The hydrogenolysis of Willstätter spruce lignin has been performed under the optimum conditions. It has been shown that on hydrogenolysis in an aqueous alkaline medium in the presence of an inhibitor (phenol) the lignin macromolecules can be converted into low-molecular-weight ether-soluble products with a yield of about 80%.2. A comparative study of the ether-soluble fractions of Willstätter spruce lignin and hydrolysis spruce lignin has shown that hydrogenolysis takes place similarly in the two cases: the yields of phenols and the proportion of cresols in them are similar. In the Willstätter spruce lignin, the yield of acids is higher and that of neutral products lower than in the hydrolysis spruce lignin.3. Investigations of the group compositions of the hydrogenolysis products and of model substances have permitted the hypothesis that the Willstätter lignin contains a considerable amount of biphenyl structures.Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 106–112, January–February, 1972.     

Radiolysis of aqueous cesium iodide

In hypothetical accident scenarios for Light Water reactors, the extent of release of iodine upon irradiation needs to be assessed for the purpose of evaluation of the applicable source term. In this context, an understanding of the behaviour of aqueous cesium iodide solutions subjected to high gamma-ray fluxes acquires significant importance. In the present work, gamma radiolysis of a cesium iodide solution (10^–2M I^–) with and without boron additive is investigated by irradiating with⁶⁰Co source at ambient temperature. Upon irradiation of the CsI solution, iodine is liberated, and the concentration of iodide in the KOH trap present in the radiolysis vessel increases with dose. The radiolytic products I ₃ ^– , IO ₃ ^– and H₂O₂ formed in the irradiated solution are also estimated and G values obtained are reported. G(I ₃ ^– ) and G(IO ₃ ^– ) are of the order of 10^–3 and 10^–4, respectively. G(H₂O₂) decreases with increase in dose. Addition of boron up to 200 ppm, does not appear to alter significantly the release fraction of iodine.     

Pulse radiolysis study of the reactivity of metal complexes of DTPA /diethylene triamine pentaacetic acid/ with OH radicals in aqueous solutions

Using the pulse radiolysis competition kinetic technique, OH radical rate constants with 12 metal DTPA complexes were determined in neutral aerated aqueous solutions. They are in the range of /1.3–5.9/×10⁹ dm³ mol^–1s^–1. To a first approximation, the rate constant was found to decrease linearly with an increase in the field strength of the metal ion (q/r²).     

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.     

Pulse radiolysis of Triton X-100 aqueous solution

Pulse radiolysis of deaerated aqueous solutions of 4·10^–5–2.4·10^–3 mol dm^–3 Triton X-100 gives rise to a transient species originating from the reactions of OH radicals and H atoms. The rate constants of these reactions were found to be 8.8·10⁹ mol^–1·dm³·s^–1 and 1.25·10⁹ mol^–1·dm³·s^–1, respectively, for Triton X-100 concentrations below CMC. The corresponding transient species were found to decay according to second order kinetics. The mechanism of the reactions involved including concentration effects is discussed.     

Pulse radiolysis of ethyl propionate in aqueous solution

Hydrated electrons (e _aq ^– ) formed in water radiolysis react with ethyl propionate with a rate parameter of 7.5×10⁷ mol^–1 dm³ s^–1. The electron adduct in acidic solutions immediately (<100 ns) dissociates, yielding CH₃CH₂C=0 radical. This process in alkaline solutions is slower, k=1.4×10⁵ s^–1. The hydroxyl radicals abstract H atoms in about 50% from the -position of propionate.     

Functional composition and IR spectra of cottonseed husk hydrolysis lignin and its derivatives

The functional compositions of cottonseed husk hydrolysis lignin and its derivatives have been determined and their IR spectra have been studied. A possible formation of stronger hydrogen bonds in derivatives of hydrolysis lignin has been shown.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. 3, pp. 392–397, May–June, 1999.     

Photophysical and photochemical properties of lignin chromophores in aqueous systems

The results are given of an investigation of the changes in the physicochemical properties of the chromophores of lignin substances of effluents by photopotential, luminescence, and ESR spectroscopy and the polarographic determination of oxygen as a function of the number of quanta of incident energy in the interval from 300 to 600 nm. It has been established that under the action of light a change in the redox properties, an increase in the rate of consumption of oxygen, the formation of radical intermediate products, and the appearance of excited triplet states of the lignin chromophores take place in the lignin substances. Action spectra of the photopotential, of the yield of EPCs of free radicals, and of the consumption of oxygen by the lignin substances in the interval from 300 to 600 nm have been obtained.Siberian Scientific-Research Institute of Cellulose and Board Bratsk. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 269–274, March–April, 1987.     

Degradation of carboxymethylstarch under the action of γ-radiation

It has been shown that the main process in the radiolysis of carboxymethylstarch (CMS) is the degradation of the polysaccharide accompanied by a contraction of the MWD. Conditions have been developed for obtaining sodium-CMS with given molecular-weight and hydrodynamic parameters.Institute of Physical Organic Chemistry, Academy of Sciences of the Belorussian SSR, Minsk. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 12–14, January–February, 1985.     

Oxidation of 3,5-dibromo-4-oxo-2,2,6,6-tetramethyl-piperidin-1-oxyl to oxoammonium bromide carried out through radiolysis of CHCl3

Using radiolysis of chloroform /CHCl₃/, 3,5-dibromo-4-oxo-2,2,6,6-tetramethyl-piperidin-1-oxyl /1/ is oxidized to its corresponding oxoammonium bromide /3/. The mechanism is a one electron oxidation forming the oxoammonium ion /3/ which is stabilized by a bromide counter ion. Br^– is generated through a one-electron reduction of /1/ resulting in a Br^– loss and the formation of a second product. The reaction is quantitative. Compound /3/ which is non paramagnetic is easily studied by NMR and gives access to the structure of /1/. Radiolysis then reveals to be a highly selective oxidation process.     

Inhibiting properties of lignin

Inhibitory efficacy has been determined by the method of the weight losses of steel in acid with native lignin, hydrolysis lignin, ammoniated native lignin, chlorinated hydrolysis lignin, and ammoniated hydrolysis lignin, and without these additives. It has been established that the efficacy of lignin and its modifications as inhibitors of acid corrosion increases with a rise in the number of carboxy groups in the macromolecule, and therefore the ammoniated hydrolysis lignin is the most effective.Central Scientific-Research and Planning Technological Institute for the Mechanization and Electrification of Animal Husbandry of the Southern Zone of the USSR. Zaporozh'e Astrakhan Technical Institute of the Fisheries Industry and Economy, Astrakhan'. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 378–380, May–June, 1983.     

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.