Catalytic oxidation of Cedar Bark (Pinus Sibirica) with Oxygen to Vanillin and Pulp

The catalytic oxidation of natural and pre-extracted cedar bark (Pinus Sibirica) by molecular oxygen is studied. Tannins were shown to inhibit the formation of vanillin while oxidizing the bark. The yields of vanillin are 5–7 wt.% based on bark lignin, which is of 3–4 times lower compared to the results of wood oxidation. The presence of tannins in the raw material complicates the lignin analysis and can overestimate the results twice

Adsorption Separation of Arsenic(III) and Arsenic(V) using Functionalized Silica Gels

A method for the adsorption separation of inorganic arsenic species (As(III)/As(V)) using sequentially connected preconcentrating columns filled with functionalized silica gels and their determination by inductively coupled plasma optical emission spectrometry was proposed. As(V) was effectively retained at pH 3.5–6.5 by an adsorbent containing groups of quaternary phosphonium bases on the surface and exhibiting the properties of an anion exchanger. In this pH range, As(III) was not extracted, which made it possible to separate As(V) from As(III). As(III) was retained in a wide pH range of 1–6 by a complexing adsorbent containing mercapto groups on the surface. Adsorbed As(V) was quantitatively eluted from the surface with 1M HNO3, and As(III) – with 5 % unithiol solution in 2M HCl. The use of «non-aggressive» eluents allows us to reuse adsorbents for preconcentration of As(III) and As(V) at least 5 times. The separation efficiency was confirmed by the analysis of model solutions

Electrochemical Study of the Reduction of Levulinic Acid in Acetonitrile on Various Electrodes

The reduction of levulinic acid by electrochemical methods in acetonitrile with or without proton donor on platinum, rhodium, glassy carbon, dropping mercury, iron, copper and lead electrodes were studied. The reduction of levulinic acid was shown to depend on the nature of electrode material and to proceed according to either electrocatalytic or electrochemical mechanisms

The Physicochemical Analysis of Bayerite Al(OH)3 → γ-Al2O3 Transformation

It was obtained aluminum hydroxide in the form of bayerite by precipitation with ammonia. The precipitation pH was found by the potentiometric titration. Based on the data of thermal, X‑ray diffraction and IR‑analysis it was identified the sequence of bayerite transitions up to 800 °C. The study of nitrogen adsorption- desorption allowed to determine a specific surface, a volume, and dimensions of pores for boehmite and γ- Al2O3 as 135±2 and 238±10 m2/g; 0.38 and 0.51 cm3/g; 1.7 and 3.8 nm, relatively. The value of effective activation energy for boehmite →γ- Al2O3 transition ((136±5) kJ/mol) was found by means of non- isothermal method (by Avrami equation)

Determination of Rare Earth Elements in Plant Samples by ICP-MS with Microwave Digestion

Method of microwave digestion using HNO3, HCl and HF in MARS‑5 system followed by ICP-MS analysis is proposed for determination of rare earth elements (REE) in plant materials. Limits of detection are 0.0001–0.001 ppm and allow for determination of all REE in certified reference materials Tr‑1, LB‑1 and EK‑1 and new reference material NSP‑1, relative standard deviations are lower than 13 %.Influence of HF addition during microwave digestion in UltraWAVE system on the ICP-MS analysis of REE in plant materials depending on silica content is studied. Necessity of HF addition during microwave digestion for better REE recoveries is shown for plant materials with Si contents exceeding 0.1 %

Properties of Granular Nitrogen-Containing Fertilizers Based on Pine Sawdust and Studying its Effectiveness in Growing Wheat in the Agricultural Zone of the Krasnoyarsk Territory

A method for producing granular fertilizers based on pine sawdust containing ammonium nitrate is proposed. Physico-chemical properties of sawdust and fertilizers containing 20.0 wt.% nitrogen were studied. The effect of pretreatment of pine sawdust with 1 % wt. with a water solution of NaOH on the properties of granular fertilizers was explored. The results of a field trial on the cultivation of wheat varieties «Krasnoyarskaya 12» revealed the growth-stimulating effect of nitrogen-containing granular fertilizers in comparison with an unfertilized background. A more effective influenceon wheat yield of granular fertilizer fabricated from pine sawdust after their treatment with 1 % wt. with a water solution of NaOHThe achieved effect on 1,9 c/ha higher in comparison with thefertilizer based on original sawdust

Composition and Structure of Ethanol-Lignins of Coniferous and Deciduous Wood and Products of their Catalytic Telomerization with 1,3-Butadiene

The composition and structure of ethanol-lignins of coniferous (abies, pine) and deciduous (aspen, birch) wood and products of their catalytic telomerization with 1,3-butadiene has been studied with use of the methods 31P-NMR, gel-permeation chromatography, scanning electron microscopy and elemental analysis. Data on the nature and content of hydroxyl groups in ethanol-lignins were obtained using phosphorylation of lignins with 2-chloro‑4,4,5,5,-tetramethyl‑1,3,2-dioxaphospholane.The studied lignins differ from each other in the content of aliphatic, phenolic and carboxyl groups. The total content of hydroxyl groups increases in the series of ethanol-lignins: birch < aspen < pine < abies. For the modification of ethanol-lignins, the reaction of catalytic telomerization with 1,3-butadiene was used at 70 °C and 90 °C in the presence of a complex of palladium (II) diacetate with the sodium salt of triphenylphosphine trisulfate. By comparing the number of aliphatic, phenolic and carboxyl OH- groups in the initial and telomerized ethanol-lignins, it was found that only aliphatic and phenolic hydroxyl groups participate in the telomerization reaction. Telomerization of ethanol-lignins with 1,3-butadiene increases their average molecular weight and reduces polydispersity. The morphology of telomerized and initial samples of ethanol-lignins varies significantly

Development of Comprehensive Analysis of Pyrolysis Products for Lignocellulose Raw Materials and Sludge Sediments by Chromatographic Methods

This paper presents a study of the pyrolysis products organic raw materials (bio-oil and sludge sediments of treatment facilities) by chromatographic methods. A feature of the work is to optimize the sample preparation procedure by fractionating the pyrolysis products. Using the method of gel permeation chromatography, molecular weight distribution of pyrolysis products was assessed. Determination of the water content in these objects (by Karl Fischer titration) was used to assess the possibility of their direct analysis by gas chromatography. A sample of sludge pyrolysis and several fractions obtained from a bio-oil sample were analyzed. By the method of two-dimensional gas chromatography, where a selfdeveloped column based on an ionic liquid was used as the first measurement column, the pyrolysate of sludge sediments and the ether fraction of bio-oil were analyzed. The obtained chromatograms and quantitative results are presented

Electrocatalytic Conversion of Levulinic Acid in Acid Medium

The electrochemical hydrogenation of levulinic acid in H2SO4 solution at aluminium, lead, graphite and glassy carbon electrodes is studied. The process is identified to proceed selectively to valeric acid. The conversion, selectivity and faradaic efficiency are significantly influenced by the material electrode nature. The levulinic acid hydrogenation at glassy carbon is shown for the first time to proceed to valeric acid, and the process selectivity is affected by the concentration of surface functionalities

Synthesis of Higher Alcohols on Silver-promoted LaCo- and LaCoCu-Perovskites

LaCoO3 and LaCo0.7Cu0.3O3 perovskites supported on highly dispersed mesoporous silica KIT‑6 were impregnated with silver nitrate (nAg/nCo = 4/99 and 8/99). The phase composition of the initial samples and samples after catalytic tests in syngas conversion and catalytic characteristics have been investigated. The regularities of the transformation of samples in the process of reduction in a hydrogen-containing gas have been studied. It is shown that, for the LaCoO3 sample, with an increase in the silver content, the activity and selectivity for higher alcohols increase from 6 to 23 %. The maximum interaction of cobalt with silver is observed at a silver content of 4 %. At a higher content, part of the cobalt is reduced regardless of the influence of silver due to its faster agglomeration. This leads to a stronger amorphization of the reduced sample and a sharp increase in its activity. The LaCo0.7Cu0.3O3 sample exhibits a higher selectivity for higher alcohols (36 %) due to the effect of copper. Silver promotion of the sample allows achieving the maximum selectivity for higher alcohols of 56 % with a silver content of 4 %. A further increase in the silver content leads to a sharp decrease in the selectivity for higher alcohols (41 %) and the appearance of CO2 due to the saturation of copper-containing particles with silver and a decrease in the interaction of cobalt with copper