Роль маркетинга в сфере культуры

Сегодня все мы ощущаем завершение очередного этапа развития нашего общества, который выражается в многочисленных кризисах (политическом, экономическом, экологическом и т.д.), что в полной мере отражает художественная культура

Ozone mediated depolymerization and solvolysis of technical lignins under ambient conditions in ethanol

Technical lignins are highly available and inexpensive feedstocks derived from current large scale biomass utilizing industries. Their valorization represents a bottleneck in the development of biorefineries, as the inherently complex lignin structure often suffers severe condensation during isolation, leading to their current application as low value fuel. Processes able to depolymerize technical lignins into value-added (intermediate) molecules are of great interest for the development of integrated, viable routes aiming at the full valorization of lignocellulosic biomass. Here, we report an effective ozone mediated depolymerization of four technical lignins (Indulin-AT Kraft, ball-milled Indulin-AT Kraft, Alcell organosolv and Fabiola organosolv) in ethanol under ambient conditions without the need for catalysts. 52–87 wt% of these nearly ethanol insoluble lignins was broken down into soluble fragments upon ozone exposure. The average molecular weight of the soluble fragments was shown to have decreased by 40–75% compared to the parent materials. A range of (di)carboxylic acids and (di)ethyl esters was identified, accounting for up to 40 wt% of the ozonated lignin oils. These products are the result of phenol ring-opening reactions as well as oxidative cleavage of unsaturated linking motifs followed by partial esterification. Reactivity varied substantially among the lignin feedstocks. For instance, lower particle sizes and higher degradation of the native lignin structure were shown to be beneficial for the effective action of the ozone. Our results show that a straightforward ozonation process under ambient conditions can depolymerize recalcitrant lignins into oxygenated fragments and low molecular weight products soluble in ethanol. These can potentially be used for the synthesis of high-value drop-in chemicals

Catalytic hydrotreatment of pyrolytic lignins from different sources to biobased chemicals:Identification of feed-product relations

The pyrolysis liquid biorefinery concept involves separation of pyrolysis liquids in various fractions followed by conversion of the fractions to value-added products. Pyrolytic lignins (PLs), the water-insoluble fractions of pyrolysis liquids, are heterogeneous, cross linked oligomers composed of substituted phenolics whose structure and physicochemical properties vary significantly depending on the biomass source. The catalytic hydrotreatment of six PLs from different biomass sources (pine, prunings, verge grass, miscanthus and sunflower seed peel) was investigated to determine the effect of different feedstocks on the final product composition and particularly the amount of alkylphenolics and aromatics, the latter being important building blocks for the chemical industry. Hydrotreatment was performed with Pd/C, 100 bar of hydrogen pressure and temperatures in the range of 350–435 °C, resulting in depolymerized product mixtures with monomer yields up to 39.1 wt% (based on PL intake). The molecular composition of the hydrotreated oils was shown to be a strong function of the PL feed and reaction conditions. Statistical analyses provided the identification of specific structural drivers on the formation of aromatics and phenolics, and a simple model able to accurately predict the yields of such monomers after catalytic hydrotreatment was obtained (R2 = 0.9944) and cross-validated (R2 = 0.9326). These feed-product relations will support future selections of PL feeds to obtain the highest amounts of valuable biobased chemicals

Pyrolytic lignin:A promising biorefinery feedstock for the production of fuels and valuable chemicals

Lignocellulosic biomass is a key feedstock for the sustainable production of biofuels, biobased chemicals and performance materials. Biomass can be efficiently converted into pyrolysis liquids (also known as bio-oils) by the well-established fast pyrolysis technology. Currently, there is significant interest in the application of fast pyrolysis technology as principle biomass conversion technology due to its feedstock flexibility, low cost and high energy conversion efficiency, with many emerging commercial enterprises being established around the globe. Upgrading of the bio-oils is a requisite, and is complicated by its complex and heterogeneous organic nature. Pyrolysis liquids may be further separated by a simple water fractionation, yielding an aqueous sugar-rich phase and a water-insoluble pyrolytic lignin (PL) fraction. This separation step allows the use of dedicated conversion strategies for each fraction, which can be highly advantageous due to their differences in composition and reactivity. For example, the sugar-rich fractions can be used for fermentation, while the phenolic-rich PL is a particularly promising feedstock for the production of a wide range of platform chemicals and energy-dense streams upon depolymerization. To aid the emerging use of PL, novel characterization techniques and valorization strategies are being explored. In this review, the fast pyrolysis process and PL characterization efforts are discussed in detail, followed by the state-of-the-art regarding PL processing using both oxidative and reductive (catalytic) strategies, as well as a combination thereof. Possible applications are discussed and recommendations for future research are provided

Valorization of humin type byproducts from pyrolytic sugar conversions to biobased chemicals

The pyrolytic sugar fraction, obtained by an aqueous extraction of pyrolysis oil, is an attractive source for sugar-derived platform chemicals. However, solids (humin) formation occurs to a significant extent during hydrolysis and subsequent acid-catalyzed conversion processes. In this study, we report investigations on possible conversion routes (pyrolysis, liquefaction) of such humin byproducts to biobased chemicals. Experiments were carried out with a model humin made from a representative technical pyrolytic sugar and the product was characterized by elemental analysis, GPC, TGA, HPLC, GC-MS, FT-IR and NMR. The obtained humin sample is soluble in organic solvents (dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), and isopropanol (IPA)), in contrast to typical more condensed humins from glucose and fructose, allowing characterization using NMR and GPC. All analyses reveal that the humins are oligomeric in nature (M-w of about 900 g/mol) and consist of sugar and furanic fragments linked with among others (substituted) aliphatic, ester units and, in addition, phenolic fragments with methoxy groups. The humins were used as a feed for catalytic pyrolysis and catalytic liquefaction experiments. Catalytic pyrolysis experiments (mg scale, programmable temperature vaporizer (PTV)-GC-MS, 550 degrees C) with HZSM-5 50 as the catalyst gave benzene-toluene-xylene-naphthalene-ethylbenzene mixtures (BTXNE) in 5.1 wt% yield based on humin intake. Liquefaction experiments (batch reactor, 350 degrees C, 4 h, isopropanol as both the solvent and hydrogen donor and Pt/CeO2 (4.43 wt% Pt) catalyst) resulted in 80 wt% conversion of the humin feed to a product oil with considerable amounts of phenolics and aromatics (ca. 24.7 % based on GC detectables in the humin oil). These findings imply that the techno-economic viability of pyrolysis oil biorefineries can be improved by converting humin type byproducts to high value, low molecular weight biobased chemicals

High-Yield 5-Hydroxymethylfurfural Synthesis from Crude Sugar Beet Juice in a Biphasic Microreactor

5-Hydroxymethylfurfural (HMF) is an important biobased platform chemical obtainable in high selectivity by the hydrolysis of fructose (FRC). However, FRC is expensive, making the production of HMF at a competitive market price highly challenging. Here, it is shown that sugar beet thick juice, a crude, sucrose-rich intermediate in sugar refining, is an excellent feedstock for HMF synthesis. Unprecedented high selectivities and yields of '90 % for HMF were achieved in a biphasic reactor setup at 150 °C using salted diluted thick juice with H2SO4 as catalyst and 2-methyltetrahydrofuran as a bioderived extraction solvent. The conversion of glucose, obtained by sucrose inversion, could be limited to '10 mol %, allowing its recovery for further use. Interestingly, purified sucrose led to significantly lower HMF selectivity and yields, showing advantages from both an economic and chemical selectivity perspective. This opens new avenues for more cost-effective HMF production

5-Hydroxy-2-Methylfurfural from Sugar Beet Thick Juice:Kinetic and Modeling Studies

5-Hydroxy-2-methylfurfural (HMF) has a high derivatization potential and is considered the sleeping giant of biobased platform chemicals. It is accessible by the acid hydrolysis of various carbohydrate-containing feeds, preferably those high in fructose content. We here report a detailed study on the use of thick juice, an intermediate sucrose (SUC)-rich stream in a sugar factory, and pure SUC for the synthesis of HMF in a batch reactor setup [in the presence of water and sulfuric acid (0.01 M) and at 180 °C]. Distinct differences in reactivity were found for both feeds, related to the presence of impurities (i.e., organic acids and salts) in the thick juice. To better understand the effect of the thick juice impurities, detailed model studies were performed involving the use of a model solution of SUC spiked with one of the thick juice impurities (organic acids such as maleic acid and a range of salts with potassium, sodium, calcium, and magnesium as the cations and carbonates, chlorides, and sulfates as the anions). The data were successfully modeled using a kinetic model for the main reactions in the network. The developed model revealed that sulfate anions have a major effect on the HMF yield and the batch time required to reach its optimum and are the likely cause of the differences in reactivity between pure SUC and thick juice

Thermoelastic Properties of Ringwoodite [Fe_x,Mg_(1-x)]_2SiO_4: Its Relationship to the 520 km Seismic Discontinuity

We combine density functional theory (DFT) within the local density approximation (LDA), the quasiharmonic approximation (QHA), and a model vibrational density of states (VDoS) to calculate elastic moduli and sound velocities of gamma-[Fe_x,Mg_(1-x)]_2SiO_4 (ringwoodite), the most abundant mineral of the lower Earth's transition zone (TZ). Comparison with experimental values at room-temperature and high pressure or ambient-pressure and high temperature shows good agreement with our first-principles findings. Then, we investigate the contrasts associated with the beta-to-gamma-[Fe_x,Mg_(1-x)]_2SiO_4 transformation at pressures and temperatures relevant to the TZ. This information offers clearly defined reference values to advance the understanding of the nature of the 520 km seismic discontinuity.Comment: 29 pages, 6 figures, 2 tables. Under Revie

Substituted anilides from chitin-based 3-acetamido-furfural

The synthesis of aromatic compounds from biomass-derived furans is a key strategy in the pursuit of a sustainable economy. Within this field, a Diels-Alder/aromatization cascade reaction with chitin-based furans is emerging as a powerful tool for the synthesis of nitrogen-containing aromatics. In this study we present the conversion of chitin-based 3-acetamido-furfural (3A5F) into an array of di- and tri-substituted anilides in good to high yields (62-90%) via a hydrazone mediated Diels-Alder/aromatization sequence. The addition of acetic anhydride expands the dienophile scope and improves yields. Moreover, replacing the typically used dimethyl hydrazone with its pyrrolidine analogue, shortens reaction times and further increases yields. The hydrazone auxiliary is readily converted into either an aldehyde or a nitrile group, thereby providing a plethora of functionalized anilides. The developed procedure was also applied to 3-acetamido-5-acetylfuran (3A5AF) to successfully prepare a phthalimide. </p