Половці: етнічна культура

У статті розглядаються структурні складові етнічної культури, формування якої відбувалося у процесі синтезу первинних і вторинних генеруючих чинників ретроспекції життєдіяльності номадів.В статье рассматриваются структурные составные этнической культуры, формирование которой осуществлялось в процессе синтеза первичных и вторичных генерирующих факторов ретроспекции жизнедеятельности номадов.Structural components of ethnic culture, formation of which was realized in the process of synthesis of primary and secondary generating factors of retrospection of nomads’ life activities are considered in the article

Polyurethane prepolymer and aqueous polyurethane dispersion

The invention relates to a polyurethane prepolymer prepared by reacting a mixture comprising a short-chain renew­ able diisocyanate and a long-chain renewable diisocyanate and one or more dials. The short-chain renewable diisocyanate has at most IO atoms and at most two ether group between the two isocyanate groups, and has at most 16 carbon atoms in the molecule. The long-chain renewable diisocyanate has either more than 12 atoms or more than ether group between the two isocyanate groups, or has more than 20 carbon atoms in the molecule. The invention also relates to an aqueous dispersion comprising the polyurethane prepolymer and a coating obtainable from the prepolymer

Synthesis of Furandicarboxylic Acid Esters From Nonfood Feedstocks Without Concomitant Levulinic Acid Formation

5-Hydroxymethylfurfural (HMF) is a versatile intermediate in biomass conversion pathways. However, the notoriously unstable nature of HMF imposes challenges to design selective routes to chemicals such as furan-2,5-dicarboxylic acid (FDCA). Here, a new strategy for obtaining furans is presented, bypassing the formation of the unstable HMF. Instead of starting with glucose/fructose and thus forming HMF as an intermediate, the new route starts from uronic acids, which are abundantly present in many agro residues such as sugar beet pulp, potato pulp, and citrus peels. Conversion of uronic acids, via ketoaldonic acids, to the intermediate formylfuroic acid (FFA) esters, and subsequently to FDCA esters, proceeds without formation of levulinic acid or insoluble humins. This new route provides an attractive strategy to valorize agricultural waste streams and a route to furanic building blocks without the co-production of levulinic acid or humins

Back-to-monomer recycling of polycondensation polymers : Opportunities for chemicals and enzymes

The use of plastics in a wide range of applications has grown substantially over recent decades, resulting in enormous growth in production volumes to meet demand. Though a wide range of biomass-derived chemicals and materials are available on the market, the production volumes of such renewable alternatives are currently not sufficient to replace their fossil-based analogues due to various factors, in particular cost-effectiveness. Hence, the majority of plastics are still industrially produced from fossil-based feedstocks. Moreover, various reports have clearly raised concern about the plastics that are not recycled at their end-of-life and instead end up in landfills or the oceans. To avoid further pollution of our planet, it is highly desirable to develop recycling processes that use plastic waste as feedstock. Chemical recycling processes could potentially offer a solution, since they afford monomers from which new polymers can be produced, with the same performance as virgin plastics. In this manuscript, the opportunities for using either chemical or biochemical (i.e., enzymatic) approaches in the depolymerization of polycondensation polymers for recycling purposes are reviewed. Our aim is to highlight the strategies that have been developed so far to break down plastic waste into monomers, providing the first step in the development of chemical recycling processes for plastic waste, and to create a renewed awareness of the need to valorize plastic waste by efficiently transforming it into virgin plastics

Fermentation for the production of biobased chemicals in a circular economy : a perspective for the period 2022-2050

Chemicals and materials produced from non-renewable, petrochemical feedstocks contribute greatly to the quality of life we currently enjoy. To ensure that quality of life is maintained in the future, it is imperative that we move towards a circular economy, where care is taken to reuse or recycle materials at their end-of-life and new chemicals and materials are sourced from renewable carbon feedstocks such as biomass. To achieve this transition, efficient conversion methods by which biomass-derived feedstocks can be converted to chemicals are required. The high degree of functionalisation (i.e. high content of oxygen atoms) of biomass-derived feedstocks, makes their conversion by microbial fermentation an interesting option. This article provides an overview of currently available fermentation technologies that have the potential to play a role in the production of biobased bulk chemicals in a circular economy in the period up to 2050. Our focus is primarily on technologies that are sufficiently mature to have been implemented on (at least) industrial pilot scale. In addition to an overview of available technologies, we provide a critical assessment of their potential relevance for use in the production of bulk chemicals in a future circular economy. We conclude that seven fermentation processes for the production of (potential) bulk chemicals have already reached a stage of technological maturity where they are ready to be applied in a circular economy. A number of other processes may reach this stage of maturity in the coming years

Incorporation of Isosorbide into Poly(butylene terephthalate) via Solid-State Polymerization

The biomass-based monomer isosorbide was incorporated into poly(butylene terephthalate) (PBT) by solid-state polymerization (SSP) using the macrodiol monomer BTITB-(OH)(2), which consists of isosorbide (I), terepluthalic acid (T), and 1,4-butandiol (B) residues. This macromonomer can be synthesized by a simple one-pot, two-step reaction. Polymers with number-average molecular weights up to 100000 g.mol(-1) were readily synthesized from various ratios of PBT/BTITB-(OH)(2). Their molecular weights, thermal properties, and colors were compared with corresponding copolyesters that were obtained by melt polycondensation. We found that T-m, T-c, and especially T-g were superior for materials that were obtained by SSP. This is ascribed to differences in the microstructures of both types of copolyesters; the SSP products exhibit a more blocky structure than do the more random melt-polymerized counterparts. The SSP method resulted in much higher molecular weights and much less colored polymers, and it seems to be the preferred route for incorporating biobased monomers that exhibit limited thermal stability into engineering plastics

Selective Production of Maleic Acid from Furfural via a Cascade Approach Combining Photochemistry and Electro- or Biochemistry

Starting from furfural, maleic acid is efficiently synthesized in two steps under very mild conditions. In the first step, 5-hydroxy-2(5H)-furanone is synthesized via photochemical oxidation and proposed as a stable intermediate. Subsequent oxidation in the second step, by either an electrochemical or enzymatic process, results in maleic acid in high yield and selectivity

Use of lignin as additive in polyethylene for food protection: Insect repelling effect of an ethyl acetate phenolic extract

Lignocellulose biorefinery processes, including the separation of plant cell-wall components, generate lignin-rich streams referred to as “lignin fractions”. Three lignin fractions with different phenol group content were dry blended with high density polyethylene (HDPE) and further extruded. The materials obtained were subsequently tested for their mechanical properties which were little affected even with 5wt% of lignin. The lignin fraction with the highest phenol group content, an ethyl acetate extract (EAL) from a technical soda lignin, showed the best performance when blended with HDPE. Besides antioxidant and antimicrobial properties (especially on S. Aureus) competing with other natural extract, the fraction conferred to the material insect repellent properties towards two types of insects, an invader (Sitophylus oryzae) and a penetrator (Plodia interpunctella). These combined properties make films made out of this material ideal candidates for protecting food that suffers attack from such insects

A Facile Solid-Phase Route to Renewable Aromatic Chemicals from Biobased Furanics

Renewable aromatics can be conveniently synthesized from furanics by introducing an intermediate hydrogenation step in the Diels-Alder (DA) aromatization route, to effectively block retro-DA activity. Aromatization of the hydrogenated DA adducts requires tandem catalysis, using a metal-based dehydrogenation catalyst and solid acid dehydration catalyst in toluene. Herein it is demonstrated that the hydrogenated DA adducts can instead be conveniently converted into renewable aromatics with up to 80% selectivity in a solid-phase reaction with shorter reaction times using only an acidic zeolite, that is, without solvent or dehydrogenation catalyst. Hydrogenated adducts from diene/dienophile combinations of (methylated) furans with maleic anhydride are efficiently converted into renewable aromatics with this new route. The zeolite H-Y was found to perform the best and can be easily reused after calcination