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We compare the effects that different extraction methods based on green chemistry principles have on the degree of extraction of constituents of Scots pine (Pinus sylvestris) tree greenery. The gas chromatography–mass spectrometry analyses show that the alcohol extract, the essential oil, and the supercritical extract differ in their qualitative and quantitative compositions. Compared to conventional methods, supercritical fluid extraction with carbon dioxide provides the highest selectivity in the extraction of the diterpenes fraction and an expanded range of constituents extracted from the tree greenery, while preserving the high antimicrobial activity of the prepared extract against the Escherichia coli strains.

Currently, cellulose is one of the most requested natural polymers and the material has a wide range of industrial applications. The most studied and extensively used source of cellulose are coniferous and deciduous wood. At the same time, taking into account the structural and chemical properties of the biopolymer, the influence on the formation of nano-, micro- and macro-characteristics, and the conditions of its biosynthesis, the industry increasingly pay attention to its alternative sources, including algae. In this work, a protein-polysaccharide complex, where cellulose is the principal component, was isolated from samples of brown algae samples collected from the White and Yellow Seas. The structural features of the brown algae cellulose complexes were studied using classical physicochemical methods, as well as FTIR spectroscopy, X-ray spectroscopy, and scanning electron microscopy Analyses revealed stable phase Iβ forms of cellulose predominated in arctic brown algal samples, and the degree of crystallinity of the cellulose product was 54–59%. Scanning electron microscopy revealed that the compound has a fibrous structure, which is most pronounced in samples derived from arctic kelp. These results expand our understanding of use of algal cellulose and macrophytes as a valuable raw material for the production of sorption and composite cellulose-based materials.

The acidity constants of a number of guaiacyl phenols simulating structural fragments of natural lignins in the electronically excited state in water–N,N-dimethylformamide mixtures are determined by fluorescence spectroscopy using the Forster cycle. The differentiating effect of an aprotic solvent on the acidity of phenols is shown. It is found that the pKa values in the excited state are associated with the properties of para-substituents with respect to the phenolic hydroxyl group. The highest capacity for acid ionization during photoexcitation is exhibited by compounds containing an electron-withdrawing carbonyl group.

Alginate/chitosan (AlgNa/Cht) aerogels and carbogels with a developed micro-mesoporous structure were produced. For the first time, the classical scheme, including the sol-gel process and supercritical fluid drying, was applied to obtain the two-component AlgNa/Cht aerogel materials with predicted properties. The obtained aerogels and carbogels have a specific surface area up to 399 m2g−1 and 549 m2g−1, respectively, and tubular pore structure. The morphological characteristics of the samples were investigated by atomic force microscopy and by scanning electron microscopy. It was shown that carbogels have narrow globular particle size distribution (35–45 nm). The synthesis conditions (critical concentration and syneresis region) are established under which the coagulum is formed in the form of an interpolyelectrolyte complex. The calcium carbonate impregnation into AlgNa/Cht system leads to an almost instantaneous formation of a hydrogel. Moreover, it allows changing material structure due to the additional nodes of the fluctuation mesh of engagement, which leads to an increase in the sizes of associative structural formations of aerogel materials, its strength, and high dimensional stability. The use of the template allowed to increase the specific surface area and the mesopores volume in the of the carbogels in 1.5–2 times. Due to such structure, the 1 g of aerogel material retains 20–35 g of water while maintaining shape. The shape of the monolith in the carbogel is maintained. Obtained AlgNa/Cht aerogels are of medical and biological interest.

Lignins are among the most common plant polymers and demonstrate pronounced electrical conductivity properties due to their conjugated polymolecular aromatic structure and polyfunctional nature. Electrical conductivity and dielectric properties of lignins from conifers and deciduous trees in the range of electric field frequencies from 10−2 to 107 Hz were investigated by means of dielectric spectroscopy. Characteristic parameters of static and high frequency electrical conductivity were calculated. To study the influence of the lignins functional nature on their electrophysical properties, the study determined three types of relaxators (separate charges or charge systems in the structure of a substance changing their position in space when exposed to an external alternating electric field) in the structure of the lignin macromolecule. Low-frequency relaxators are associated with oscillations of methoxyl groups. Mid-frequency relaxators correspond predominantly to phenolic hydroxyl groups and to hydroxyl groups of adsorbed water. High-frequency relaxators correspond to the hopping of π-electrons along the chain of conjugated bonds of a benzene ring. Differences in the structure and functional nature of lignins from conifers and deciduous trees cause different contributions of low-frequency relaxators. As a result, these features form differences in the electrophysical properties of lignins from conifers and deciduous trees.

The extraction of polyphenol component of arctic brown algae of the Fucus vesiculosus type and the subsequent fractionation of the extract by column chromatography on a Sephadex LH-20 adsorbent are carried out. The obtained fractions are characterized by size-exclusion chromatography, HPLC with UV and mass spectrometric detection (HPLC–UV-MS), and matrix-assisted laser desorption/ionization mass spectrometry (MALDI–MS). Using the MALDI–MS method, the presence of oligomeric compounds containing up to 13 phloroglucin structural units is detected. Using HPLC–UV-MS, oligomeric compounds in the mass range 374–870 Da (trimers–octamers) are detected, and their ratio is estimated.

—Aerogel materials based on the interpolymer complex of alginate with chitosan using supercritical fluids technology were obtained. It was established that obtained aerogels have a developed mesoporous structure and a specific surface area of up to 243 m2/g. The average pore size equals 14.8 nm. The possibility of using the aerogels with the inclusion of antibiotic levomycetin as a basis for creating wound dressings was shown. It was estimated that slow release of the drug (70% during 5 h) from the aerogel matrix provides prolonged and safe supply of the drug to the surface of a wound.

—Some results of studying the effect of the thermochemical activation of biomass on the degree and efficiency of the extraction of phenolic compounds from Juniperus communis L. wood with supercritical CO2 and various cosolvents are presented. Phenolic components in the obtained extracts were identified by high-performance liquid chromatography. It has been shown that the use of protonic cosolvents provides the extraction of much higher amounts of phenolic compounds, in particular, vanillin and vanillic acid.

This study presents results for the isolation, fractionation and characterization of Arctic brown algae polyphenols. New analytical data on the structure, functional nature and polymolecular properties of brown algal phlorotannins were obtained using modern analytical methods (size exclusion chromatography, liquid chromatography–mass spectrometry and fluorescence spectroscopy). The interrelation of radical scavenging activity and molecular weight of the algal polyphenolic components has also been established. Relatively high radical scavenging activity (776 ± 36 mg of ascorbic acid per g of extract) is observed for phlorotannin subfractions with average molecular weights from 8 to 18 kDa, enriched with phlorotannin oligomers with three to eight phloroglucinol units. Radical scavenging activity decreases with increasing molecular mass.

Introduction Juniperus communis L. is a wood species used in folk medicine since it has a variety of wood extractives with a wide range of pharmacological properties. The morphological features of juniper wood structure leads to the necessity for the application of activation, which facilitates extraction of wood extractives. The methods of thermochemical activation can be used to improve the existing schemes of extraction. Objective This work aims to develop methods that increase the selectivity and efficiency of the extraction of pharmacological biologically active substances from the Juniperus communis wood. Methodology The thermochemical activation of the juniper wood matrix involves treatment by steam explosion and the use of supercritical fluid extraction methods. Gas chromatography mass spectrometry analysis was used to identify the components of the obtained extracts. Results It is shown that the supercritical fluid extraction by a binary solvent facilitates the extraction of the maximum amount of sesquiterpene and diterpene alcohols, terpene oxides and ketones. Extracts obtained during the two-stage process with the traditional extraction in a Soxhlet apparatus at the first stage and the supercritical fluid extraction at the second, contain squalene as the main component. The two-stage treatment with steam explosion at the first stage facilitates the extraction of the maximum amount of diterpene alcohols having the widest range of biological activity. Conclusion The research demonstrates the prospects of application of the methods of thermochemical activation of plant raw materials for the extraction of the wide spectrum of terpene components.

The electrophysical properties of slightly altered sample of lignin are studied via dielectric spectroscopy in the frequency range of 10–2 to 106 Hz and temperature range from −120 to 160°C. The results are processed using the Havriliak–Negami frequency dispersion model. The presence of several dielectric constant relaxation mechanisms is confirmed. The energy of activation for temperature-dependent relaxation is determined.

A new approach to the formation of “fullerene-like” carbon-nitrogen carbogels based on the interpolyelectrolyte complex lignosulfonate-chitosan (IPEC LSNa-CT) was developed. It was established that carbogel maintained the morphology of the precursor complex, i.e. the spherical geometry and the particle size of its main fractions (40–55 nm) were stored in the carbonizate. The influence of pyrolysis (Py) temperature was studied in the range of 500–1000°C on the structure of carbonizate. Carbogels obtained under different processing conditions have a well-developed microporous structure. The specific surface area of carbogels reduced with increasing Py temperature according to their nitrogen content. The maximum specific surface area (438.3 m2 g−1) corresponds to the carbogel obtained at 600°C, while the maximum nitrogen content of this sample is 4.4%. The internal porosity of the material and the volume of supermicropores are reduced with increasing Py temperature due to the accumulation of double and triple carbon bonds in the carbogel. Apparently, the structure-forming N-atoms participate in the formation of condensed nitrogen-containing and cyclic structures as a donor of the electron pair and as such they accelerate the carbonization process.

The biochemical processes of synthesis and self-organization of the components of the lignin-carbohydrate matrix lead to the formation of a complex multi-component system considered as a nanobiocomposite, which is a thermodynamically limited ordered system of biopolymers in quasi-equilibrium. The concept of the thermodynamic state of the lignin–carbohydrate matrix and the possibility of regulating the areas of thermodynamic compatibility of components due to chemical and/or physical impact allow to consider the supercritical fluid technologies (SCFTs) as a tool for directing changes in the biocomposite’s structure and properties at the molecular level and also as a way of creating essentially new technologies for the complex processing of plant raw materials.

The Nucleodur HILIC zwitterionic stationary phase was characterized by linear solvation energy relationship (LSER) analysis in the supercritical fluid chromatography mode. It was shown that the main contribution to retention is made by hydrogen bonding interactions.

Natural lignins are one of the most widespread biopolymers. The main active centers in the lignin macromolecules are phenolic hydroxyl groups. They form lignin macromolecules reactivity. The lignin is considered as a natural polyphenol. The main characteristics of the lignin reactivity are their acid–base and redox properties. Acid–base properties of lignins are characterized by pKa values of basic types of phenolic structures. The redox properties are characterized by effective oxidation potential and the Gibbs energy of the phenolic structures. This paper studies the acid–base and redox properties of the phenolic structures of coniferous and deciduous natural lignins. The authors analyze the representative slightly altered preparations of dioxane lignin extracted from coniferous wood (spruce, common juniper) and deciduous wood (common aspen). The study reveals the differences in the reaction properties of coniferous and deciduous lignins due to their functional nature and macromolecular properties.

The fatty acid composition of arctic brown algae was studied using supercritical (SC) fluid extraction. A method for fractionating the SC extract based on the differences in the solubility of its components (fatty acids, polyphenols) was proposed. The composition and biological activity of the fractions were studied.

The thermochemical activation of the lignocarbohydrate matrix by supercritical (SC) fluid extraction was studied. Labile and stable regions of lignocarbohydrate formations distributed in the cell wall were revealed. Changes in the composition and morphology of the wood substance during the treatment were determined. Supercritical fluid extraction with carbon dioxide was shown to be a useful method for selective treatment of the weak H-bonds of the lignocarbohydrate complex to obtain new data on the structure and composition of the wood substance and its components.

Enterosorption properties of algae fiber were studied. Determination of the thermodynamic characteristics of heavy metal sorption showed that the process is endothermic with the prevalence of chemisorption interactions. Algae fiber exhibits high sorption capacity for heavy metals and pathogenic microorganisms.

Aspects of the formation of gels of interpolyelectrolyte complexes (IPECs) based on sodium alginate (NaAlg) and chitosan are studied. The effect the conditions of synthesis and complex composition have on the morphological structure and functional properties of these complexes is examined. It is established that complexation in this system proceeds according to a mechanism of electrostatic interaction between the oppositely charged carboxylic groups of the L-hyaluronic acid pyranose cycles of NaAlg proximal polymer chains and chitosan’s amino groups, along with a multitude of hydrogen bonds and dispersion forces. We show that the mechanism of IPEC formation is strongly influenced by the conformational state of a lyophilizing component that is present in the system in excess. The inner surfaces of cryogels based on NaAlg‒chitosan IPECs is found to be strongly influenced by the degree of conversion between the parental polyelectrolytes. The most developed mesoporous structure is obtained when a denser gel forms in the system.

A scheme for producing cellulose from the artic brown algae Fucus vesiculosus and Laminaria digitata was proposed. The physicochemical and structural features of the cellulose samples were studied and compared with those of celluloses from higher plants. Cellulose from Fucus vesiculosus was found primarily in the Iα-form; from Laminaria digitata, the Iα- and Iβ-forms. The studied samples were assumed to contain slightly crystalline cellulose with a structure similar to that of cellulose II. Its content was typically greatest in F. vesiculosus (58%).

Publications dedicated to the application of supercritical fluids in the advanced processing of plant raw materials for the production of a wide range of products such as ethanol, liquid and gaseous fuels, sugars, organic acids, and oils are reviewed and analyzed. The specific features of the supercritical fluid technologies and their advantages over the existing traditional methods for the processing of plant raw materials are demonstrated.

Derivatives of benzoic and cinnamic acids are secondary metabolites of plants, widely distributed in nature and possessing biological activity. Supercritical fluid chromatography (SFC) is shown to provide a high performance separation of nine most important representatives of this class of compounds with selectivity, dramatically different from the reversed-phase high-performance liquid chromatography. The retention and chromatographic separation parameters of analytes for four stationary phases of different nature are compared and the effect of supercritical fluid parameters and the composition of the mobile phase onto the chromatographic separation are analyzed. The optimal separation is found to be achieved when using a silica-based sorbent with 2-ethylpyridinium linked groups. The proposed approach for determination of the above-mentioned compounds is based on the combination of chromatographic separation with multiwavelength spectrophotometric detection and provides the detection limits in the range of 13.0–51.3 μg/L and the analysis duration about 2.5 min. The approach is successfully tested on real objects, such as different kinds of wine.

The supercritical fluid extraction of chlorophylls and carotenoids from marine algae Fucus vesiculosus and Laminaria digitata with carbon dioxide was studied. Complete extraction of carotenoids with carbon dioxide was achieved at a pressure of 250 atm and a temperature of 80°C after 20 min in the absence of a cosolvent. Extraction of chlorophylls in high contents required the use of a polar co-solvent (ethanol, 10–15 vol %) or extraction time increased to 50–90 min (at a co-solvent consumption of

The advantages of application of supercritical fluid technologies at the stages of complex wood and plant processing are analyzed based on the modern concept of lignin-carbohydrate matrix formation.

The mechanism of the interpolyelectrolyte interaction and structural and morphological features of sodium lignosulfonate—chitosan complexes were studied. The optimum conditions for producing composite membranes were selected. It was found that the deformation and strength attributes of the membranes were determined by the structural and molecular properties of the biopolymers incorporated into the interpolymer complex and could be enhanced by adding cellulose fiber to the composite.

Four polar stationary phases (ethylene-bridged hybrid silica, cyanopropyl, 2-ethylpyridine, and zwitterionic sulfobetaine) have been characterized in supercritical fluid chromatography (SFC) by linear free energy relationships (LFER) method with an extended set of Abraham's descriptors. Temperature (25–55 °C) and pressure (110–180 bar) effects on analyte retention, separation selectivity and LFER-coefficients of chromatographic systems have been studied using the 89 test compounds of various chemical classes and carbon dioxide – methanol (9:1 v/v) binary solvent as a mobile phase. It was found that for the selected stationary phases temperature and pressure had only moderate effects on selectivity. The retention times of all analytes decrease, as can be expected, if the pressure rises at the isothermal conditions due to the increase of the fluid density and its eluting power. The effect of temperature on retention is complicated and depends both on the chemical class of analyzed compounds and the stationary phase type. Temperature and pressure variations lead to small changes in the LFER-coefficients, and general trends observed do not depend much on the stationary phase type. It may be difficult to interpret the LFER-analysis results because of the evident, more significant chromatographic phenomena.