The present study describes an interesting and practical catalytic system that allows flexible conversion of lignin into aromatic or aliphatic hydrocarbons, depending on the hydrogen partial pressure. A combination of experiment and theory shows that the product distribution between aromatics and aliphatics can be simply tuned by controlling the availability of hydrogen on the catalyst surface. Noticeably, these pathways lead to almost complete oxygen removal from lignin biomass, yielding high-quality hydrocarbons. Thus, hydrogen-lignin co-refining by using this catalytic system provides high flexibility in hydrogen storage/consumption towards meeting different regional and temporal demands.

• Klíčová slova
• biomass, hydrogen, lignin, renewable energy, waste valorization,
• Publikační typ
• časopisecké články MeSH

The valorization of lignins as renewable aromatic feedstock is of utmost importance in terms of the use of sustainable resources. This study provides a deductive approach towards market-oriented lignin-derived antioxidants by ascertaining the direct effect of different structural features of lignin on the reactivity of its phenolic OH groups in the radical scavenging reactions. The antioxidant activity of a series of compounds, modeling lignin structural units, was experimentally characterized and rationalized, using thermodynamic descriptors. The calculated O-H bond dissociation enthalpies (BDE) of characteristic lignin subunits were used to predict the modification pathways of technical lignins. The last ones were isolated by soda delignification from different biomass sources and their oligomeric fractions were studied as a raw material for modification and production of optimized antioxidants. These were characterized in terms of chemical structure, molecular weight distribution, content of the functional groups, and the antioxidant activity. The developed approach for the targeted modification of lignins allowed the products competitive with two commercial synthetic phenolic antioxidants in both free radical scavenging and stabilization of thermooxidative destruction of polyurethane films.

• Klíčová slova
• antioxidant activity, lignins, modification, molecular rationalization, stabilizers for polymers,
• MeSH
• antioxidancia chemická syntéza   MeSH
• dimerizace MeSH
• elektrony MeSH
• kinetika MeSH
• lignin chemie   MeSH
• polyfenoly chemie   MeSH
• polyurethany chemie   MeSH
• protonová magnetická rezonanční spektroskopie MeSH
• spektroskopie infračervená s Fourierovou transformací MeSH
• teoretické modely * MeSH
• teorie funkcionálu hustoty * MeSH
• teplota MeSH
• vodík chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antioxidancia MeSH
• lignin MeSH
• polyfenoly MeSH
• polyurethany MeSH
• vodík MeSH

The trend of emerging biorefineries is to process the harvest as efficiently as possible and without any waste. From the most valuable phytomass, refined medicines, enzymes, dyes and other special reactants are created. Functional foods, food ingredients, oils, alcohol, solvents, plastics, fillers and a wide variety of other chemical products follow. After being treated with nutrient recovery techniques (for fertilizer production), biofuels or soil improvers are produced from the leftovers. Economic optimization algorithms have confirmed that such complex biorefineries can be financially viable only when a high degree of feedstock concentration is included. Because the plant material is extremely voluminous before processing, the farming intensity of special plants increases in the nearest vicinity of agglomerations where the biorefineries are built for logistical reasons. Interdisciplinary analyses revealed that these optimization measures lead to significantly increased pollen levels in neighbouring urban areas and subsequently an increased risk of allergies, respectively costs to the national health system. A new moral dilemma between the shareholder's profit and public interest was uncovered and subjected to disputation.

• Klíčová slova
• Bioeconomy, Financial optimization, Logistics, Moral dilemma, Public health costs,
• MeSH
• alergie etiologie   MeSH
• analýza nákladů a výnosů MeSH
• biomasa MeSH
• biopaliva * MeSH
• biotechnologie MeSH
• etika podnikání MeSH
• lidé MeSH
• mravy MeSH
• poskytování zdravotní péče ekonomika   MeSH
• průmysl ekonomika   etika   MeSH
• průmyslová hnojiva * MeSH
• pyl škodlivé účinky   MeSH
• rostliny * MeSH
• sociální odpovědnost MeSH
• technologie * MeSH
• vystavení vlivu životního prostředí škodlivé účinky   etika   MeSH
• zemědělství ekonomika   etika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• biopaliva * MeSH
• průmyslová hnojiva * MeSH