Search

People wear clothes for warmth, survival and necessity in modern life, but in the modern era, eco-friendliness, shortened production times, design and intelligence also matter. To determine the relationship between data series and verify the proximity of each data series, a gray relational analysis, or GRA, is applied to textiles, where seamless bonding technology enhances the bond between components. In this study, a polyurethane prepolymer, 2-hydroxyethyl acrylate (2-HEA) as an end-capping agent and n-octyl acrylate (ODA) as a photoinitiator were used to synthesize a dual-curing polyurethane hot-melt adhesive. Taguchi quality engineering and a gray relational analysis were used to discuss the influence of different mole ratios of NCO:OH and the effect of the molar ratio of the addition of octyl decyl acrylate on the mechanical strength. The Fourier transform infrared spectroscopy (FTIR) results showed the termination of the prepolymer's polymerization reaction and the C=O peak intensity at 1730 cm−1, indicating efficient bonding to the main chain. Advanced Polymer Chromatography (APC) was used to investigate the high-molecular-weight (20,000–30,000) polyurethane polymer bonded with octyl decyl acrylate to achieve a photothermosetting effect. The thermogravimetric analysis (TGA) results showed that the thermal decomposition temperature of the polyurethane hot-melt adhesive also increased, and they showed the highest pyrolysis temperature (349.89 °C) for the polyhydric alcohols. Furthermore, high peel strength (1.68 kg/cm) and shear strength (34.94 kg/cm2) values were detected with the dual-cure photothermosetting polyurethane hot-melt adhesive. The signal-to-noise ratio was also used to generate the gray relational degree. It was observed that the best parameter ratio of NCO:OH was 4:1 with five moles of monomer. The Taguchi quality engineering method was used to find the parameters of single-quality optimization, and then the gray relation calculation was used to obtain the parameter combination of multi-quality optimization for thermosetting the polyurethane hot-melt adhesive. The study aims to meet the requirements of seamless bonding in textile factories and optimize experimental parameter design by setting target values that can effectively increase production speed and reduce processing time and costs as well. [ABSTRACT FROM AUTHOR]

The ability to utilize a number of polyhydric alcohols as a sole carbon source has been studied in the Yarrowia lipolytica yeast. The efficiency of the promoter of the Y. lipolytica native AraDH2 gene encoding the enzyme D-mannitol/D-arabitol dehydrogenase was assessed during yeast growth on a minimal medium with different carbon sources. For this purpose, the promoter region of the AraDH2 gene was transcriptionally fused with the green fluorescent protein hrGFP gene, and the construct was used to transform Y. lipolytica. A β-carotene producing strain of Y. lipolytica was created using the described promoter; the strain carried the Mucor circinelloides CarRP and CarB genes encoding the bifunctional enzyme phytoene synthase/lycopene β-cyclase (CarRP) and phytoene dehydrogenase (CarB) as well as the GGPPSs7 gene Synechococcus sp. geranylgeranyl pyrophosphate synthase. The nucleotide sequence encoding the fused CarRP and GGPPSs7 under the regulation of the pAraDH2 promoter and the CarB gene under the control of the pTEF promoter were introduced into the yeast genome. As a result, a transformant was obtained capable of producing 66.3, 121.2, and 148.9 mg/L of β-carotene after 5 days of cultivation in test tubes on media containing glycerol, sucrose, and glucose, respectively. The obtained results testify to the high potential of the pAraDH2 promoter in the field of genetic engineering. [ABSTRACT FROM AUTHOR]

For the first time, the studies of polyhydric alcohols (glycerol, ethylene glycol and propylene glycol) impact on the structure, deformation–strength characteristics and hemocompatibility of the film materials based on chitosan and N-succinyl chitosan were carried out. It was shown that the introduction of polyhydric alcohols into molding solutions during the creation of the films based on chitosan and succinyl chitosan in the amount up to 0.05 mol/l is accompanied by the tensile elongation value increase by 2–2.5 times. The value of the breaking stress in this case decreases by 3–4 times. There is also a decrease in the overall surface roughness and a sharp drop in the elastic modulus of the films. The stabilizing impact of the systems based on chitosan and succinyl chitosan in the presence of glycerol and propylene glycol upon the cell membranes in physiological conditions allows inferring their high hemocompatibility.

[Display omitted] • Green and efficient polyhydric alcohols were used for room temperature VALLME of TBHQ selectively from biodiesel. • Polyhydric alcohols-based VALLME method that takes only 1 min to conduct. • The accurate analysis of TBHQ content in various biodiesels was achieved by ethylene glycol-based VALLME coupled with RP-HPLC. The antioxidant tert -Butylhydroquinone (TBHQ) in biodiesel is easily oxidized to tert -Butylquinone (TQ), which adversely affects the accurate determination of TBHQ. In this work, different polyhydric alcohols based deep eutectic solvents (DESs), the corresponding polyhydric alcohols and methanol were used as solvents in the room temperature vortex-assisted liquid–liquid microextraction (VALLME) for TBHQ from biodiesel samples. And ethylene glycol shows the most effective extraction for TBHQ due to the similar polarity. Conventional method use methanol as the extraction solvent, which will extract both TBHQ and TQ at the same time, and TQ will be reduced to TBHQ in the process of RP-HPLC analysis, resulting in false alarms of high detection values; whereas, attributed to the higher polarity of ethylene glycol, it is more favorable for extracting polar TBHQ than the less polar TQ, thus it can be achieved the accurate determination of TBHQ with the commonly used RP-HPLC method. Analytical performance of the developed method was investigated. The limit of detection (LOD) and the limit of quantitation (LOQ) were 0.02 mg/kg and 0.06 mg/kg, respectively. The recovery of TBHQ was between 94.06 % and 99.82 %, while RSDs for the intra-day and inter-day precisions were 4.27 % and 2.92 %, respectively. The developed method can be applied in various biodiesel samples originated from different vegetable oils with the recoveries ranged from 87.07 % to 106.09 %. This method using ethylene glycol as the solvent for VALLME is simple and cheap, which shows potential application in the field of biodiesel products quality monitoring and control. [ABSTRACT FROM AUTHOR]

A convenient method has been developed for the synthesis of 3,5-bis(hydroxymethyl)adamantan-1-ols via successive nitroxylation of 1,3-bis(acetoxymethyl)adamantanes with fuming nitric acid, alkaline hydrolysis of intermediate 3,5-bis(acetoxymethyl)adamantane-1-yl nitrates, and reaction of the resulting 3,5-bis(hydroxymethyl)adamantan-1-yl nitrates with hydrazine hydrate. 3,5-Bis(hydroxymethyl)adamantan-1-ols have been converted to the corresponding trinitrates by treatment with fuming nitric acids in acetic anhydride. [ABSTRACT FROM AUTHOR]

Copyright of China Brewing is the property of China Brewing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The formation of unsaturated carbonyl compounds in irradiated aqueous solutions of polyhydric alcohols has been studied using spectrophotometry, HPLC, and chemical analysis. Some spectral characteristics of these products have been determined, and they almost coincide with those calculated according to Woodward–Fieser rules. [ABSTRACT FROM AUTHOR]

In the present study, the effectiveness of a mixture of silver nanoparticles with polyhydric alcohols (glycerol, erythritol, mannitol and xylitol) against six species of healthpromoting bacteria have been examined. Synthesis of silver nanoparticles was carried out using trisodium citrate as the reducing and stabilizing agent. The nanoparticles were characterized by electronic absorption, scanning electron microscopy and powder X-ray diffraction measurements. Electronic absorption spectrum revealed high uniform of synthesized nanoparticles. Practically no aggregation was observed when nanoparticles were mixed with polyhydric alcohols, suggesting weak interaction between ingredients of the mixture. Spherical silver nanoparticles, as depicted by scanning electron microscopy, were found to have diameters in the range of 10 to 30 nm; mean diameter was 18 ± 4 nm. The X-ray diffraction pattern of the prepared samples indicated the face-centred cubic crystalline structure of the metallic silver nanoparticles. In biological study, quite interesting protective effect of polyalcohols on the growth inhibition of health-promoting bacteria by silver nanoparticles was observed. The most substantial protective effect of the tested silver nanoparticles-polyalcohol mixtures was estimated for B. bifidum, L. paraplantarum, and L. phamnosus species. [ABSTRACT FROM AUTHOR]

• Liquefaction process using organic acids as catalyst was investigated. • Kraft lignin liquefaction yield has not been influenced by the type of the catalyst. • The highest hydroxyl number in liquefied products was obtained with lactic acid. • Viscosity varied with catalysts and the molecular weights were reduced. In this work, three different organic acid catalysts, (acetic acid, lactic acid and citric acid), are proposed as an alternative to common catalysts used in the liquefaction process of Kraft lignin. These organic acids can easily be obtained from renewable resources and their application as a catalyst could allow the development of more environmentally friendly process in the production of biopolyols. The main objective of the present work was to study the influence of these organic acids catalysts and their concentration (3%, 6% and 9%, w/w) on the yield and properties of the obtained liquefied products. The results demonstrated that the type of the organic catalysts (85–88%) has not influenced the liquefaction yield of Kraft lignin. The highest hydroxyl number was obtained with lactic acid at 3% (660.08 mg KOH.g−1), whereas acetic acid provided the lowest acid number (0.80 mg KOH.g−1). The viscosity varied with catalysts (114.5–345.8-mPa.s) and the molecular weights of the liquefied products were in the range of 1459-1990 g.mol−1, lower than Kraft lignin (3866 g.mol−1). Moreover, volatile compounds showed traces of lignin derivatives and a few intermediate products from solvents. The low lignin signals observed by ATR-IR in the solid residue as well as the obtained liquefaction yields, suggested that most of the Kraft lignin has reacted during liquefaction process. The obtained results showed the potential value of these organic compounds to be used as renewable and more environmentally friendly catalysts in the liquefaction of Kraft lignin. [ABSTRACT FROM AUTHOR]

Cellulose extraction from banana pseudo-stem by liquefaction in polyhydric alcohols was subjected to kinetic analysis. • The kinetics and thermodynamics of liquefaction of BPs were investigated. • Liquefied products soluble in water and acetone were separated and characterized. • The optimum liquefaction condition to maximize cellulose content in LR was identified. • Mechanism of cellulose micro-fibril extraction from BPs by liquefaction was proposed. The objective of this work is to track the composition changes in the process of liquefaction of banana pseudo-stem (BPs) and to maximize the cellulose fraction in the liquefied residue. Typical kinetics parameters of raw BPs and its three major components (lignin, hemicellulose and cellulose) were determined using kinetic models and transition-state theory. The results showed that cellulose had the highest activation energy and lowest reaction rate. The liquefied polyols were separated by water and acetone, and the functional groups, molecular weight distribution, acid values and hydroxyl values of different soluble parts were analyzed, providing an overall insight into the liquefaction behavior of BPs. The most suitable liquefaction conditions to avoid polycondensation and maximize cellulose content in the residues was at 150 °C with a reaction time of 90 min. Cellulose-enriched residues were readily purified by subsequent bleaching treatments. Based on the results of SEM, XRD, FTIR, TG and wet chemistry analyses, a mechanism of cellulose micro-fibril extraction from solid liquefied residues was proposed. [ABSTRACT FROM AUTHOR]

The oil palm tree is a monocotyledon, and the chemical composition varies relative to the part of its trunk. Therefore, the purpose of this study was to investigate the relationship between the chemical composition in different parts of an oil palm trunk and the rate of liquefaction. PEG#400/glycerol (4:1, w/w) was the liquefying reagent with 2% sulfuric acid as a catalyst. Liquefaction was done at the optimum conditions of liquor ratio, temperature (130 to 180 °C), and reaction time (30 to 120 min). The results revealed that the rate of liquefying was dependent on the part of the trunk. The inner zone in the top parts of the trunk had the least amount of lignin and lowest crystallinity. Thus, these parts could be liquefied faster than the other parts of the trunk. According to FTIR, XRD, and 13C NMR analyses, the amorphous polymer content (comprised of lignin, hemicellulose, and disordered zones of cellulose and starch) mostly degraded at the low temperature of 140 °C for 30 min, while the crystalline regions required higher temperature (180 °C). Increasing the temperature had stronger effects than extending reaction time or the liquor ratio. Furthermore, excess in these reaction parameters caused re-condensation of the degraded liquefied products. [ABSTRACT FROM AUTHOR]

The bio‐synthesis of palladium nanocubes (PdNCs) was realised using pine needle extract as the reducing agent and cetyl trimethyl ammonium bromide as the capping agent. As an eco‐friendly and readily available biomass, pine needle extract avoided the use of highly polluting chemical reducing agents. The growth process of PdNCs was analysed using ultraviolet–vis and Fourier transform infrared spectroscopy. Flavonoids, esters, terpenoids and polyhydric alcohols, which contain reductive groups, were mainly responsible for the transition of Pd2+ ions to PdNCs. The morphology and structure of PdNCs were characterised using transmission electron microscopy (TEM), high‐resolution TEM, selected area electron diffraction and X‐ray diffraction. It was indicated that the as‐prepared PdNCs displayed a relatively high purity and good crystallinity with a face‐centred cubic structure and exhibited sizes ranging from 6.11 to 29.51 nm with an average particle size of 11.18 nm. In the methanol electro‐oxidation reaction, the PdNCs enclosed by {100} facets exhibited superior electro‐catalytic activity to commercial Pd/C, which was rarely reported in other bio‐synthesis processes for Pd catalysts. Meanwhile, the PdNCs showed excellent anti‐poisoning ability and long‐term stability. This study reveals the possibility of preparing shape‐controlled PdNCs with a specific structure and excellent electro‐catalytic activity. [ABSTRACT FROM AUTHOR]

Banana pseudo-stem was liquefied in the mixture of polyhydric alcohols of polyethylene glycol (PEG400) and glycerol. Hydroxyl value of liquefied products ranged from 294.8 to 370.2 mg KOH/g and M¯n was about 430. Liquefied products (LBPP) could be used as raw materials for polyurethane by reacting with 4, 4'-diphenylmethane diisocyanate (4, 4'-MDI) and PEG400 to synthesize liquefied product-based polyurethane (LBPP-PU) adhesive. To analyze in depth the creation of urethane linkage among LBPP, PEG400 and 4, 4'-MDI, factors which had effects on the residue content were all investigated. They were characterized by FT-IR and TG. The shear strength of LBPP-PU adhesive was improved when decreasing the percentage of the substitution of PEG400 by LBPP. The adhesive strength was obtained from T-peel of aspen/polyurethane adhesive joints, and the maximum lap shear strength (4.40 MPa) was obtained when 16.70% of LBPP was added to the LBPP & PEG400 system. [ABSTRACT FROM AUTHOR]

In this study, polyhydric alcohols, including glycerol, erythritol, xylitol, mannitol, and inositol, were chosen as carbon precursors for preparation of carbon adsorbents via phosphoric acid activation. The thermal behaviors of phosphoric acid-treated polyhydric alcohols revealed the formation and decomposition of organic phosphates at low temperatures, which enhanced the creation of functional groups on activated carbon. In general, the activated carbons showed relative low surface area (the highest one of 509 m 2 /g for AC-xylitol) due to the low activation temperature, and low yields (the highest one of 36.6% for AC-xylitol) due to the volatilization and decomposition of organic phosphates. The activated carbons contained 50–90% larger total amount of surface groups than the reference activated carbon derived from lignocellulose material, which mainly resulted in their 40–75% higher Ni(II) adsorption capacity. These results also indicated that the polyhydric alcohols-based activated carbons can be promising candidates for Ni(II) removal. [ABSTRACT FROM AUTHOR]

The effects of polyhydric alcohols (glycerol, propylene glycol), surfactants (SLES, CAPB, APG), emollients (stearic acid, IPM, Cetiol CC, Cetiol HE) and emulsifiers (Simusol 165, S1170) on the phase behavior of fatty acid soaps prepared with lauric acid, myristic acid and stearic acid mixtures (25% total fatty acids) were studied. Phase behaviors were analyzed by pH, viscosity, turbidity, clarity, polarization optical microscopy and X-ray diffraction. The results show that the composition of ternary fatty acid mixtures plays a decisive role in the phase behavior of soap solutions. An increase in the level of steric acid promotes the formation of the Liq + Crystal phase. Polyhydric alcohols made the liquid-phase (liquid micelle phase) region larger. Surfactants also increased the liquid-phase region by solubilizing insoluble fatty acid soaps. Liquid-phase soap systems were stable for at least 2 months. Emollients were solubilized by fatty acid soap micelles leading to the formation of the Cub + Hex and Liq + Lam phases. Emulsifiers showed excellent solubilizing properties in the system of fatty acid soaps and emollients. The liquid-phase region became larger, reducing the Cub + Hex phase region and keeping the Liq + Crystal phase more compact and stable. The Cub + Hex phase and Liq + Lam phase were metastable with the system eventually separating into multiple phases over time. [ABSTRACT FROM AUTHOR]

Tensioactive compounds, such monohydric or polyhydric alcohols cause that with an increase in their concentration in solutions, surface tension at the liquid-gas interface – γ LG, and wetting angle at the interface silicon-solution – θ LS decrease. It means that on both the surfaces an adsorption layer of the alcohol occurs. It results in lowering of etch rates of some silicon crystallographic planes. In this work, the values of γ LG and θ LS for selected monohydric and polyhydric alcohols (diols) have been compared and etch rates and morphologies of silicon substrates Si(100) and Si(110) etched in KOH solutions containing these alcohols have been determined. Advantages of diols and possibilities of their using in silicon anisotropic etching have been considered. [ABSTRACT FROM AUTHOR]

In this work, plasma electrolytic technology was successfully employed to achieve fast liquefaction of sawdust when polyethylene glycol 200 (PEG 200) and glycerol were used as liquefacient in the presence of the catalyst sulfuric acid. Results showed that H ions could heat the solution effectively during the plasma electrolytic liquefaction (PEL) process. The influence of some key parameters including liquefaction time, catalyst percentage, liquefacient/sawdust mass ratio, and PEG 200/glycerol molar ratio on the liquefaction yield were investigated. Based on the results of single factor experiments, response surface methodology (RSM) was applied to optimize the liquefaction process. Under the optimal conditions that is liquefaction time of 5.10 min, catalyst percentage of 1.05%, liquefacient/sawdust mass ratio of 7.12/1 and PEG 200/glycerol molar ratio of 1.40/1, the liquefaction yield reached 99.48%. Hence, it could be concluded that PEL has good application potential for biomass fast liquefaction. [ABSTRACT FROM AUTHOR]

The integral enthalpies of dissolution Δ H for N-acetylglycine in aqueous solutions of glycerol, ethylene glycol and 1,2-propylene glycol are measured via solution calorimetry. The standard enthalpies of dissolution (Δ Н ) and transfer (Δ Н ) for N-acetylglycine from water to aqueous solutions of polyhydric alcohols are calculated from experimental data. Positive values of enthalpy coefficients of pair interactions h for amino acids and polyol molecules are calculated using the McMillan-Mayer theory. The results are discussed using an approach for evaluating different types of interactions in ternary systems and the effect the structural features of interacting biomolecules have on the thermochemical characteristics of N-acetylglycine dissolution. [ABSTRACT FROM AUTHOR]

The solvolysis behavior and reaction kinetics of the three components of biomass (cellulose, hemicelluloses and lignin) liquefied in polyhydric alcohols (PEG 400 or glycerol) were investigated in this paper. Three stages were observed during the solvolysis process and the main degradation stage could be further divided into two zones. The influences of solvents on the liquefaction process of three main components were compared. Based on Starink and Malek methods, kinetic parameters and mechanism functions were obtained. The derived average activation energy of cellulose, hemicellulose and lignin were 108.73, 95.66 and 94.13 kJ mol −1 in PEG 400, while the values were 102.16, 77.43 and 89.10 kJ mol −1 in glycerol, respectively. Higher efficiency was observed when using glycerol as solvent, which could be ascribed to the higher polarity value of glycerol. The conversion curves calculated with obtained mechanism models and kinetic parameters were in good agreement with the experimental data. [ABSTRACT FROM AUTHOR]

A novel design of liquid catalyzed fuel cell (LCFC), which uses polyoxometalates (POMs) as the photocatalyst and charge carrier has been reported previously. In this paper, the adaptability of biomass fuels (e.g., glycerol and glucose) to the LCFC and corresponding cell performance were studied in detail here. An interesting finding that greatly differs from conventional fuel cell is that high molecular weight fuels rather than small molecule fuels (e.g., methanol and ethylene glycol) are favored by the novel LCFC with respect to the power densities. The power output of LCFC strongly depends on the number and structure of hydroxyl groups in the biomass fuels. The evidence of UV–Vis and 1 H NMR spectra shows that the preassociation between POM and alcohol fuels, which determines the photoelectrochemical reaction pathway of POM, is enhanced as the number of hydroxyl increases. Experimental results also demonstrate that more hydroxyl groups in the molecules lead to faster photoelectrochemical reaction between POM and fuels, higher reduction degree of POM, and further higher power output of LCFC. Our study reveals that biomass-based polyhydroxyl compounds such as starch, hemicellulose and cellulose are potential high-performance fuels for LCFC. [ABSTRACT FROM AUTHOR]

This work demonstrated the possibility of hydrophobic ionic liquid tricaprylmethylammonium thiocyanate ([A336][SCN]) as a solvent in the separation by extraction of polyhydric alcohols from their mixtures with water. The knowledge of (liquid + liquid) equilibrium (LLE) of these mixtures is essential for the design of the extraction process. For this reason, the LLE data of the ternary systems {[A336][SCN] + water + glycerol, or ethylene glycol, or 1,2-propanediol, or 1,3-propanediol} were determined at T = 303.2 K and atmospheric pressure. The reliability of the tie-lines data was ascertained by applying the Othmer–Tobias equation, and the non-random two liquid (NRTL) model used to fit the experimental LLE data. The effectiveness of the extraction of polyhydric alcohols from water was evaluated using the solute distribution ratio and the selectivity. The extraction capability of [A336][SCN] was compared with that of other ILs. The results indicated that the [A336][SCN] was suitable for use as a solvent in (liquid + liquid) extraction of polyhydric alcohols from water. [ABSTRACT FROM AUTHOR]

BACKGROUND Based on the biorefinery concept, the main focus of this work was the increase in value of spent coffee grounds via an acid liquefaction process using polyhydric solvents in the presence of sulfuric acid, at moderate temperature. For that purpose the effect of temperature, sulfuric acid concentration and time on biomass conversion was studied using design of experiments combined with statistical analysis. RESULTS The ANOVA results (95% confidence level) showed that temperature is the factor with most influence on biomass conversion, within the studied range, while reaction times above 40 min don't seem to bring significant advantages. The maximum conversion obtained in this study was 70 wt% which was achieved at 160°C, 4 wt % of catalyst and 80 min. The polyol obtained using these conditions presented a hydroxyl number value of 199 mg KOH/g polyol and a viscosity of 390 cP, at 25°C. CONCLUSION This work showed that it is possible to convert spent coffee grounds into liquid polyols via an acid liquefaction process at moderate temperature and autogeneous pressure. These polyols have similar properties to those of petroleum-based polyols typically used in the polyurethane foam industry. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Integral enthalpies of dissolution Δ H of L-cysteine, L-serine, and L-asparagine in aqueous solutions of 1,3-propylene glycol at organic solvent concentrations of up to 0.26 mole fraction are measured via the thermochemistry of dissolution. Standard enthalpies of dissolution (Δ H) and transfer (Δ H) of amino acids from water to a mixed solvent are calculated. It is found that the calculated enthalpy coefficients of pair interactions of the amino acids with polyhydric alcohol molecules have positive values. The effect the arrangement of the hydroxyl group in the structure of polyhydric alcohols has on the enthalpy of interaction of amino acids in aqueous solutions is revealed. The effect of different types of interactions in solutions and the structural features of biomolecules and cosolvents on the enthalpy of dissolution of amino acids is analyzed. [ABSTRACT FROM AUTHOR]

Bagasse was subjected to a liquefaction process with polyethylene glycol/glycerol using sulfuric acid as catalyst. The effects of various liquefaction conditions, such as reaction time, liquefaction temperature, catalyst content, and liquid ratio (liquefaction solvents/bagasse), on the liquefied residue (LR) content and hydroxyl and acid numbers of liquefied products were investigated. The preferred liquefaction condition of bagasse was determined through orthogonal experiments. The results showed that the catalyst content and reaction time have a greater influence than liquid ratio and liquefaction temperature on the percentage of LR. The hydroxyl and acid numbers of the liquefied products were influenced by many factors, including liquefaction temperature, reaction time, acid content, and liquid ratio. The hydroxyl number of liquefied products decreased as the liquefaction reaction progressed, but the acid number of liquefied products increased. Based on the obtained data, the kinetics for liquefaction was modeled using the first-order reaction rate law and the apparent activation energy for the liquefaction of bagasse was estimated to be 38.30 kJ mol. [ABSTRACT FROM AUTHOR]

Copyright of Silva Lusitana is the property of Unidade de Investigacao de Silvicultura e Productos Florestais and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: Acid hydrolysis residue (AHR) of corncob was liquefied using glycerol as main liquefaction solvent. The effects of various liquefaction conditions such as reaction time, liquefaction temperature, catalyst content, ratio of polyol/AHR and glycerol concentration on the liquefied residue content have been studied in this paper. The liquefied product was separated into three fractions: a water-soluble part, an acetone-soluble part and a residue. Fourier transform infrared (FT-IR) analyses showed that the acetone-soluble part mainly included degradation products from lignin, the water-soluble fraction mainly contained liquefaction solvent and its derivate and cellulose degradation products, the residue mainly contained lignin derivatives. The gas chromatography and mass spectrometry (GC–MS) analyses showed that liquefied products of AHR included alcohols, acids, esters, alkanes, phenols and their derivatives. [Copyright &y& Elsevier]

Abstract: Using di-2-pyridyl ketonoxime (Hdpko) as an oxime-based ligand in combination with several polyhydric alcohols, viz. ethanediol (H2ed), propanediol (H2pd) and pentaerythritol (H4per), we have synthesized a series of trinuclear complexes involving a linear MnII–MnIV–MnII core, viz. [Mn3(dpko)4(ed)Cl2]·2CH3CN·H2O 1, [Mn3(dpko)4(pd)Cl2]·CH3CN·H2O·0.5H2pd 2 and [Mn3(dpko)4(H2per)Cl2]·4H2O 3, respectively. The trinuclear complexes contain mixed valent MnII–MnIV–MnII units in a linear topology in which MnII and MnIV spin carriers are ferromagnetically coupled. The temperature dependence of the magnetic susceptibility has been fitted with a liner spin trimer model based on the H =−2J{S Mn1·S Mn2 + S Mn1′·S Mn2} Heisenberg Hamiltonian with J/k B =+1.4(1)K for 1; +4.9(1)K for 2 and +3.7(1)K for 3, leading for the three complexes to an S T =13/2 ground state. [Copyright &y& Elsevier]

Abstract: Liquid–liquid equilibria for hexafluorophosphate ionic liquids with 1-alkyl-3-methylimidazolium family of cations: 1-butyl-3-methylimidazolium, [bmim]+, 1-hexyl-3-methylimidazolium, [hmim]+, 1-octyl-3-methylimidazolium, [omim]+ with polyhydric alcohols: 1,2-ethanediol, 1,2-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol have been measured using the cloud point method. The influence of different characteristics of alcohols and ILs, including cation alkyl chain length, alcohol chain length, and relative position of the both OH groups in alcohol were studied. In general, the same type of the phase behavior is observed in all cases showing upper critical solution temperature but the impact of the above-mentioned factors is highly diversified. [Copyright &y& Elsevier]

Abstract: The powders of cornstalk were liquefied in polyhydric alcohols using sulfuric acid as catalyst at 130–190°C for different reaction times. The kinetics along with liquefaction ratio was analyzed using kinetic models under different reaction temperatures. The result indicated that the liquefaction of cornstalk in polyhydric alcohols was multilevel. The apparent reaction rate constants increased with the increase of reaction temperatures. The apparent activation energy (E′) was 73.6kJmol−1 and the apparent frequency factor (A′) was found to be 8.8×105 S−1. According to transition-state theory, the apparent activation free enthalpy (ΔG′), apparent activation enthalpy (ΔH′), and apparent activation entropy (ΔS′) of liquefaction reaction slightly changed with temperature. With regards to apparent activation enthalpy, the result indicated that the liquefaction of cornstalk in polyhydric alcohols was predominantly an endothermic reaction in nature. [ABSTRACT FROM AUTHOR]

Abstract: Liquefaction of bagasse and cotton stalks was conducted by using polyhydric alcohols (polyethylene glycol PEG#400 and glycerin) in the presence of sulfuric acid (SA) as a catalyst. The effects of different liquefaction conditions, such as ratio raw material/liquefying solvent, effect of PEG#400/glycerin, acid concentration, liquefaction temperature and time on the liquefaction yield have been investigated. The hydroxyl and acid numbers for some liquefied samples were also determined. The results showed that the minimum residue content was obtained at 1/5 raw material to liquefying solvent. PEG#400 alone is not favoured as liquefying solvent as it gives ∼19% residual content for bagasse and ∼22% for cotton stalks at the optimum studied reaction conditions. Replacing 10% of PEG#400 with glycerin as well as increasing the SA concentration, liquefaction temperature or time, decreased the amount of residue for both bagasse and cotton stalks to less than 10%. The hydroxyl number of the produced polyols slowly decreased from 253 to 223mg KOH/g on extending the reaction time till 120min and the residual polyols prevented re-condensation of the liquefied components. It seems that this system can be applied on various types of lignocellulosic agricultural residues. [Copyright &y& Elsevier]

Abstract: Reverse nonequilibrium molecular dynamics in the canonical ensemble and coupled–decoupled configurational-bias Monte Carlo simulations in the Gibbs ensemble were used to predict the low-shear rate Newtonian viscosities and vapor–liquid coexistence curves for 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, and 1,2,4-butanetriol modeled with the transferable potentials for phase equilibria-united atom (TraPPE-UA) force field. Comparison with available experimental data demonstrates that the TraPPE-UA force field yields very good predictions of the viscosities and vapor–liquid coexistence curves. A detailed analysis of liquid structure and hydrogen bonding is provided. [Copyright &y& Elsevier]

The influence of polyhydric alcohols (sorbitol, xylitol, erythritol, glycerol) on the thermal stability of Rhizomucor miehei lipase has been studied at high hydrostatic pressure (up to 500 MPa). In the absence of additives, a protective effect (PE) (the ratio between the residual activities determined at 480 MPa for the enzyme in the presence or absence of polyhydric alcohols) of low-applied pressures (from 50 MPa to 350 MPa) against thermal deactivations (at 50°C and 55°C) has been noticed. In the presence of additives, a strong correlation between PE and the total hydroxyl group concentration has been obtained, for the first time, under treatments of combining denaturing temperatures and high hydrostatic pressures. This relationship does not seem to be dependent on the nature polyhydric alcohols as the same effect could be observed with 1 M sorbitol and 2 M glycerol. This PE, against thermal and high pressure combined lipase deactivation, increases with polyhydric alcohol concentrations, and when temperature increases from 25°C to 55°C. [ABSTRACT FROM AUTHOR]

Actomyosin isolated from fish varied from other vertebrate actomyosin. Ca 2+ ATPase activity of fish actomyosin showed the maximum activity at pH 9.0. The enzyme activity decreased with increase in temperature. Polyhydric alcohols, such as sorbitol and mannitol, inhibited the Ca 2+ ATPase activity of fish actomyosin. Mannitol was more potent inhibitor of the activity than sorbitol. An amount of 0.2M of mannitol and 0.3M of sorbitol in solution completely inhibited the Ca 2+ ATPase activity. The reduction in the intrinsic fluorescence intensity of actomyosin was insignificant in presence of these polyols. The inhibition of actomyosin Ca 2+ ATPase activity is associated with reduction in the free SH content. Secondary structure of actomyosin recorded a marginal increase in the α-helicity in presence of these polyols. These polyols reduced the nucleotide degrading property of actomyosin without alteration in the structure of molecules. [ABSTRACT FROM AUTHOR]

We have reported in the previous International Meetings on Ferroelectricity that glycerol shows the glassy state below a certain temperature, T a Recently we have found that the activation energy to complete the glassy state is 0.18–0.19 eV for all polyhydric alcohols. Furthermore we have found that the activation energy decreases little by little with the increase of amount of addition of water. Such a result is very important to know the mechanism of the formation of glassy state and to clarify the molecular structure in glass. [ABSTRACT FROM AUTHOR]

The effect of different-sized polyhydric alcohols on the absorption and circular dichroic spectra of the purple membrane has been studied over the wavelength region 800 to 185 nm. Analysis of both the solution and the film spectra of the membrane revealed that these solvents induce conformational changes in the sole membrane protein, bacteriorhodopsin. Additional evidence supportive of these changes was obtained from protein fluorescence spectral studies. Although the net secondary structure of the bacteriorhodopsin is not observably altered, there is a reversible change in the protein tertiary structure. This change does not result in any significant change in the membrane crystallinity or the alignment of the protein helical polypeptide segments with respect to the membrane plane. However, it is of sufficient extent to change the protein-induced screw sense of the retinyl-chromophore symmetry and the local environments of the protein aromatic residues. The underlying mechanism appears to be a membrane surface-solvent interaction phenomenon since the spectral perturbation caused by these solvents appears to be independent of their effective sizes. Furthermore, partial enzymatic removal of the hydrophilic portion of the bacteriorhodopsins with papain increased the response of the membrane to this perturbation. An interpretation of these results is that polyhydric alcohols enhance hydrophobic interactions in the purple membrane which induces a more compact conformation of the bacteriorhodopsin. A possible molecular mechanism is presented. [ABSTRACT FROM AUTHOR]

A survey of representative studies on the oxidation of mono- and polyhydric alcohols on gold and platinum electrodes is given, with a special attention to the reaction mechanisms and the effect of the molecular structure of these compounds on their electrocatalytic reactivity. [ABSTRACT FROM AUTHOR]

Changes in polyol production and the intracellular amino acid pool were followed during the growth cycle of Debaryomyces hansenii in 4 mM and 2.7 M NaCl media. The intracellular levels of polyols were markedly enhanced by high salinity, the dominant solutes being glycerol in log phase cells and arabinitol in stationary phase cells. At low salinity arabinitol was the most prominent intracellular solute throughout the growth cycle. There were no major changes in the composition of the total amino acid pool with changes in cultural salinity. The amount of total free amino acids related to cell dry weight was 15-50% lower in cells cultured in 2.7 M NaCl as compared to 4 mM NaCl media. After subtraction of contributions from intracellular polyols the calculated cellular C/N ratio was found to be unaffected by cultural age and salinity during the late log and early stationary phase. On prolonged incubation of stationary phase cells, this ratio decreased, particularly at high salinity. The sensitivity of cells towards exposure to high salinity was measured in terms of the length of the lag phase after transference to 2.7 M NaCl media. This lag phase decreased with increasing intracellular polyol concentrations. At a given polyol content, stationary phase cells were considerably less sensitive than were log phase cells. When cultured at high salinity the mutant strain, 26-2b, grew more slowly and retained less of the total polyol produced during the early growth stages than did the wildtype. Exogenously supplied mannitol, arabinitol, and glycerol stimulated the growth of the mutant in saline media. Erythritol was without effect. [ABSTRACT FROM AUTHOR]

Polyurethane (PU) and polyhydric alcohols composites were successfully prepared to be used as coating materials for fabrics. The effects of various polyhydric alcohols on the PU composites properties have been investigated. The tensile strengths, glass‐transition temperatures, thermal‐mechanical properties, and swelling capacities of the PU/polyhydric‐alcohol‐blended films are described in detail, along with their surface and cross‐sectional morphologies. The tensile strengths and glass‐transition temperatures of the PU/polyhydric‐alcohol‐blended films were found to decrease remarkably with increasing polyhydric‐alcohol concentration. The swelling capacities and porosities of the PU/poly(propylene glycol) (PPG)‐blended and PU/glycerol‐blended films were observed to increase with increasing PPG or glycerol concentration. However, the poly(ethylene glycol) (PEG) concentration in the PU/PEG‐blended film did not significantly affect its properties. The air and water‐vapor permeability of nonwoven nylon fabrics coated with PU/PPG and PU/glycerol increased with increasing PPG or glycerol contents, while those coated with PU/PEG were unaffected by PEG content. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47429. [ABSTRACT FROM AUTHOR]