Preparation of Polyurethane Adhesives from Crude and Purified Liquefied Wood Sawdust

Polyurethane (PU) adhesives were prepared with bio-polyols obtained via acid-catalyzed polyhydric alcohol liquefaction of wood sawdust and polymeric diphenylmethane diisocyanate (pMDI). Two polyols, i.e., crude and purified liquefied wood (CLW and PLW), were obtained from the liquefaction process with a high yield of 99.7%. PU adhesives, namely CLWPU and PLWPU, were then prepared by reaction of CLW or PLW with pMDI at various isocyanate to hydroxyl group (NCO:OH) molar ratios of 0.5:1, 1:1, 1.5:1, and 2:1. The chemical structure and thermal behavior of the bio-polyols and the cured PU adhesives were analyzed by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Performance of the adhesives was evaluated by single-lap joint shear tests according to EN 302-1:2003, and by adhesive penetration. The highest shear strength was found at the NCO:OH molar ratio of 1.5:1 as 4.82 ± 1.01 N/mm2 and 4.80 ± 0.49 N/mm2 for CLWPU and PLWPU, respectively. The chemical structure and thermal properties of the cured CLWPLW and PLWPU adhesives were considerably influenced by the NCO:OH molar ratio.

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Yield and Quality Characteristics of Brassica Microgreens as Affected by the NH4:NO3 Molar Ratio and Strength of the Nutrient Solution

Foods ◽

10.3390/foods9050677 ◽

2020 ◽

Vol 9 (5) ◽

pp. 677 ◽

Cited By ~ 2

Author(s):

Onofrio Davide Palmitessa ◽

Massimiliano Renna ◽

Pasquale Crupi ◽

Angelo Lovece ◽

Filomena Corbo ◽

...

Keyword(s):

Nutrient Solution ◽

Inorganic Ions ◽

Molar Ratio ◽

High Yield ◽

Nitrate Content ◽

Carotene Content ◽

Molar Ratios ◽

Half Strength ◽

Nutrient Solutions ◽

Β Carotene

Microgreens are gaining more and more interest, but little information is available on the effects of the chemical composition of the nutrient solution on the microgreen yield. In this study, three Brassica genotypes (B. oleracea var. italica, B. oleracea var. botrytis, and Brassica rapa L. subsp. sylvestris L. Janch. var. esculenta Hort) were fertigated with three modified strength Hoagland nutrient solutions (1/2, 1/4, and 1/8 strength) or with three modified half-strength Hoagland nutrient solutions with three different NH4:NO3 molar ratios (5:95, 15:85, and 25:75). Microgreen yields and content of inorganic ions, dietary fiber, proteins, α-tocopherol, and β-carotene were evaluated. Micro cauliflower showed the highest yield, as well as a higher content of mineral elements and α-tocopherol (10.4 mg 100 g−1 fresh weight (FW)) than other genotypes. The use of nutrient solution at half strength gave both a high yield (0.23 g cm−2) and a desirable seedling height. By changing the NH4:NO3 molar ratio in the nutrient solution, no differences were found on yield and growing parameters, although the highest β-carotene content (6.3 mg 100 g−1 FW) was found by using a NH4:NO3 molar ratio of 25:75. The lowest nitrate content (on average 6.8 g 100 g−1 dry weight) was found in micro broccoli and micro broccoli raab by using a nutrient solution with NH4:NO3 molar ratios of 25:75 and 5:95, respectively. Micro cauliflower fertigated with a NH4:NO3 molar ratio of 25:75 showed the highest dry matter (9.8 g 100 g−1 FW) and protein content (4.2 g 100 g−1 FW).

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Gold Clustering at Dimethylsulfoximine Me2S(O)NH

Zeitschrift für Naturforschung B ◽

10.1515/znb-2000-1001 ◽

2000 ◽

Vol 55 (10) ◽

pp. 889-894 ◽

Cited By ~ 2

Author(s):

Armin Hamel ◽

Christian Hollatz ◽

Annette Schier ◽

Hubert Schmidbaur

Keyword(s):

Nitrogen Atom ◽

Dinuclear Complex ◽

Trinuclear Complex ◽

Molar Ratio ◽

High Yield ◽

X Ray Diffraction ◽

X Ray ◽

Molar Ratios ◽

Pyramidal Configuration ◽

Unknown Structure

Abstract Gold Clustering, Dimethylsulfoximine Polyaurated complexes of the dimethylsulfoximide anion [Me2S(O)N]- have been prepared by reacting N-trimethylsilyl-dimethylsulfoximide with [(Ph3P)Au]BF4 in various molar ratios. With one or two equivalents of the gold(I) reagent only the dinuclear complex is obtained in high yield: {[(Ph3P)Au]2NS(O)Me2}+ BF4- . With three or four equivalents only the trinuclear complex is produced: {[(Ph3P)Au]3NS(O)Me2}2+ 2 BF4- . No mono- or tetra-auration was observed, respectively. The composition of the compounds has been confirmed by analytical and spectroscopic data, and the crystal structure of the dinuclear compound has been determined by single crystal X-ray diffraction of the dichloromethane solvate. The two gold atoms are found to be coordinated to the nitrogen atom with a small Au-N-Au angle of only 92.3(3)° and a short Au-Au distance of 2.9900(5) Å. The nitrogen atom is in a distorted trigonal pyramidal configuration which allows an intramolecular SO-Au contact. For the trinuclear complex a structure with a tetracoordinate nitrogen atom [SNAU3] is proposed which is analogous to the corresponding complexes of phosphinimines R3P=NH. With the ditertiary phosphine Ph2PCH2Ch2PPh2 (dppe) a cyclic dinuclear complex (dppe)Au2[NS(0 )Me2]BF4 can be synthesized starting from (dppe)Au2Cl2. The reaction of the phosphine-rich precursor [(Ph3P)2Au]BF4 with Me3SiNS(0 )Me2 in the molar ratio 2:1 affords a binuclear complex {[(Ph3P)2Au]2NS(0 )Me2}BF4 of an as yet unknown structure

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Some Features of Cycloalkylation Reactions of Phenol with 1-Methylcyclopentene

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.899.726 ◽

2021 ◽

Vol 899 ◽

pp. 726-732

Author(s):

Fatma I. Gasimova ◽

Zaur Z. Aghamali̇yev ◽

Gulshan J. Gasanova ◽

Chingiz K. Rasulov

Keyword(s):

Reaction Time ◽

Nmr Spectroscopy ◽

Physicochemical Parameters ◽

Molar Ratio ◽

High Yield ◽

Target Product ◽

Molar Ratios ◽

Chemical Structures ◽

Effective Conditions ◽

Yield Of Target Product

The present study deals with the investigation of catalytic cycloalkylation reactions of phenol with 1-methylcyclopentene. KU-23 and aluminum phenolate were used as catalysts for the process. The effect of kinetic parameters (temperature, duration, molar ratios of the initial components and the amount of catalyst) on the yield and selectivity of methylcyclopentyl phenols obtained as a result of scientific research was investigated. As a result, effective conditions were found for the production of para- and ortho-, ortho- (1-methylcyclopentyl) phenols with high yield and selectivity. It was determined that high yield of target product in the presence of phenol, 1-methylcyclopentene and catalyst KU-23, was 71.2% for phenol and selectivity for target product - 92.8% is obtained under the following conditions of cycloalkylation reaction: temperature 110°C, reaction time-5 hours, molar ratio phenol to methylcyclopentene-1 : 1, the amount of catalyst-10% according to the phenol taken. The cycloalkylation reaction of phenol with 1-methylcyclopentene in the presence of aluminum phenolate catalyst was carried out in an autoclave in a nitrogen environment and effective conditions were found: temperature 260°C, reaction time - 5 hours, molar ratio of phenol to 1-methylcyclopentene 1: 2, amount of catalyst 20% according to the phenol taken. Under these conditions, the yield of the target product is 44.3% for the phenol taken, and the selectivity is 87.6% for the target product. The chemical structures of the synthesized para- and ortho-, ortho- (1-methylcyclopentyl) phenols were confirmed by IR-, 1H and NMR spectroscopy, and physicochemical parameters were determined.

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Tc-Glutathione Complex (Tc -GSH) : Labelling, Chemical Characterization and Biodistribution in Rats

Metal-Based Drugs ◽

10.1155/mbd.1999.329 ◽

1999 ◽

Vol 6 (6) ◽

pp. 329-336 ◽

Cited By ~ 4

Author(s):

K. Baba ◽

J. L. Moretti ◽

P. Weinmann ◽

R. Senekowitsch-Schmidtke ◽

M. T. Ercan

Keyword(s):

Chemical Structure ◽

Isotope Labeling ◽

Chemical Characterization ◽

Molar Ratio ◽

High Yield ◽

Visible Spectroscopy ◽

Nmr Studies ◽

Yield Result ◽

Specific Organ ◽

Uv Visible

The chemical structure of T99mc -GSH has been estabilished using the T99c isotope. Labeling of glutathione with technetium in the presence of stanous chloride gave a high yield result. In a comparative study between T99c and T99mc glutathione, the Tc-GSH complex obtained was purified and characterized by uv, visible spectroscopy, HPLC, Biogel chromatography, mass and NMR spectroscopy. Stoichiometric analysis showed a 2 : 1 molar ratio of GSH/Tc for the reaction. The molecular mass assessed by mass spectroscopy was 727 Da corresponding to an oxo(bis) glutathione technetate. NMR studies demonstrated that each glutathione molecule was coordinated to technetium via cysteinyl sulfur and nitrogen atoms. The biodistribution of the complex was studied in normal rats. Blood clearance was rapid during the first hour involving a biexponential curve ( t1/2 (1) : 50 min, t1/2 (2) : 400 min ). No radioactive accumulation was found in any specific organ except kidney and bladder. All the activity excreted was found unchanged in urine. In conclusion, Tc-GSH displayed an anionic dimer form as GSH-Tc-GSH. We assume that the complex is a tetradentate (2N,2S) complex containing a pentavalent technetium coordinated by two thiol and nitrogen atoms of both GSH ligands, and an apical oxo group.

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Studies on the Esterification Synthesis of Alkyl Oleates in Solvent-Free System by Candida Sp. Lipase

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.634-638.599 ◽

2013 ◽

Vol 634-638 ◽

pp. 599-603

Author(s):

Hui Zhong ◽

Zheng Fang ◽

Bao Hua Zou ◽

Xin Li ◽

Kai Guo

Keyword(s):

Oleic Acid ◽

High Selectivity ◽

Enzyme Concentration ◽

Solvent Free ◽

Hydroxyl Group ◽

Molar Ratio ◽

High Yield ◽

Free System ◽

Candida Sp ◽

Solvent Free System

The alkyl oleates were prepared by esterification of oleic acid with alkyl alcohols catalyzed by the lipase from Candida sp. 99-125 in solvent-free system. The influence of several factors, including enzyme concentration, temperature, molar ratio between oleic acid and alkyl alcohols and the structures of alcohols, was also investigated. The results indicated that the reactions catalyzed by lipase at 20 oC, in the presence of 5% (w/w) lipase, on the molar ratio of 1:1 between oleic acid and alcohols, afforded products in high yield and showed high selectivity to the alcohols with less hindrance on hydroxyl group. The lipase from Candida sp. 99-125 was identified to be an effective catalyst in the esterification of alcohol and oleic acid at low temperature.

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Preparation of Polyurethane Adhesive from Wood Sawdust polyol: Application of Response Surface Methodology for Optimization of Catalyst and Glycerol

Biointerface Research in Applied Chemistry ◽

10.33263/briac122.18701883 ◽

2021 ◽

Vol 12 (2) ◽

pp. 1870-1883

Keyword(s):

Response Surface Methodology ◽

Response Surface ◽

Adhesive Bonding ◽

Ethylene Carbonate ◽

Hydroxyl Groups ◽

Polyurethane Adhesive ◽

Wood Sawdust ◽

Lap Shear ◽

Liquefied Wood ◽

Liquefaction Process

Response surface methodology (RSM) was applied to optimize catalyst and glycerol values as suitable additives in polyurethane adhesive production and determine the appropriate gel time. Polyurethane adhesive was prepared using polyol, two types of diisocyanate (PMDI and TDI), catalyst, and glycerol with equal NCO/OH ratio. Polyol was produced using the liquefaction process of Beechwood sawdust with ethylene carbonate solvent at 130°C for 120 minutes under atmospheric pressure. Fourier transform infrared spectroscopy (FTIR) results revealed the existence of the hydroxyl groups in the liquefied wood and confirmed that the liquefied wood sawdust is a source of polyols and a potential chemical stock for the synthesis of polyurethane. Also, the adhesive bonding strength was evaluated by lap shear strength. The result of optimization by response surface methodology showed that catalyst and glycerol values were 0.11% and 1.56% for PU adhesive with PMDI, and catalyst and glycerol values of 0.34% and 3.12%for PU adhesive with TDI were appropriate.

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Structural Characterization and Antioxidant Activity of Exopolysaccharide from Soybean Whey Fermented by Lacticaseibacillus plantarum 70810

Foods ◽

10.3390/foods10112780 ◽

2021 ◽

Vol 10 (11) ◽

pp. 2780

Author(s):

Juanjuan Tian ◽

Qingyan Mao ◽

Mingsheng Dong ◽

Xiaomeng Wang ◽

Xin Rui ◽

...

Keyword(s):

Antioxidant Activity ◽

Chemical Structure ◽

Functional Foods ◽

Structural Characteristics ◽

Exchange Chromatography ◽

High Yield ◽

Molar Ratios ◽

Chelating Ability ◽

Soybean Whey ◽

Fermentation Substrate

Soybean whey is a high-yield but low-utilization agricultural by-product in China. In this study, soybean whey was used as a substrate of fermentation by Lacticaseibacillus plantarum 70810 strains. An exopolysaccharide (LPEPS-1) was isolated from soybean whey fermentation by L. plantarum 70810 and purified by ion-exchange chromatography. Its preliminary structural characteristics and antioxidant activity were investigated. Results show that LPEPS-1 was composed of mannose, glucose, and galactose with molar ratios of 1.49:1.67:1.00. The chemical structure of LPEPS-1 consisted of →4)-α-D-Glcp-(1→, →3)-α-D-Galp-(1→ and →2)-α-D-Manp-(1→. Scanning electron microscopy (SEM) revealed that LPEPS-1 had a relatively rough surface. In addition, LPPES-1 exhibited strong scavenging activity against DPPH and superoxide radicals and chelating ability on ferrous ion. This study demonstrated that soybean whey was a feasible fermentation substrate for the production of polysaccharide from L. plantarum 70810 and that the polysaccharide could be used as a promising ingredient for health-beneficial functional foods.

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Synthesis and mechanical and thermal properties of multiblock terpoly(ester-ether-amide) thermoplastic elastomers with variable mole ratio of ether and amide block

Polish Journal of Chemical Technology ◽

10.2478/pjct-2021-0032 ◽

2021 ◽

Vol 23 (4) ◽

pp. 10-16

Author(s):

Beata Schmidt ◽

Joanna Rokicka

Keyword(s):

Thermal Properties ◽

Chemical Structure ◽

Thermoplastic Elastomers ◽

Molar Ratio ◽

Mechanical And Thermal Properties ◽

Molecular Weights ◽

Molar Ratios ◽

Ft Ir ◽

Trimethylene Terephthalate ◽

Nmr Methods

Abstract A series of the terpolymers of poly[(trimethylene terephthalate)-block-(oxytetramethylene)-block-laurolactam] with a variable molar ratio of ether and amide block and constant molecular weights of PA12 = 2000 g/mole and PTMO = 1000 g/mole have been obtained. The influence of changes of these molar ratios on the functional properties and the values of phase change temperatures of the products have been determined. The thermal properties and the phase separation of obtained systems were defined by DSC, DMTA and WAXS methods. The chemical structure of obtained materials was studied by FT-IR and 13C NMR methods. The mechanical and elastic properties of these polymers were evaluated.

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Reactivity of Aliphatic and Phenolic Hydroxyl Groups in Kraft Lignin towards 4,4′ MDI

Molecules ◽

10.3390/molecules26082131 ◽

2021 ◽

Vol 26 (8) ◽

pp. 2131

Author(s):

Leonardo Dalseno Antonino ◽

Júlia Rocha Gouveia ◽

Rogério Ramos de Sousa Júnior ◽

Guilherme Elias Saltarelli Garcia ◽

Luara Carneiro Gobbo ◽

...

Keyword(s):

Experimental Work ◽

Chemical Structure ◽

31P Nmr ◽

Kraft Lignin ◽

Hydroxyl Group ◽

Hydroxyl Groups ◽

Diphenylmethane Diisocyanate ◽

Complex Chemical ◽

Heterogeneous Reactivity ◽

Phenolic Hydroxyl Groups

Several efforts have been dedicated to the development of lignin-based polyurethanes (PU) in recent years. The low and heterogeneous reactivity of lignin hydroxyl groups towards diisocyanates, arising from their highly complex chemical structure, limits the application of this biopolymer in PU synthesis. Besides the well-known differences in the reactivity of aliphatic and aromatic hydroxyl groups, experimental work in which the reactivity of both types of hydroxyl, especially the aromatic ones present in syringyl (S-unit), guaiacyl (G-unit), and p-hydroxyphenyl (H-unit) building units are considered and compared, is still lacking in the literature. In this work, the hydroxyl reactivity of two kraft lignin grades towards 4,4′-diphenylmethane diisocyanate (MDI) was investigated. 31P NMR allowed the monitoring of the reactivity of each hydroxyl group in the lignin structure. FTIR spectra revealed the evolution of peaks related to hydroxyl consumption and urethane formation. These results might support new PU developments, including the use of unmodified lignin and the synthesis of MDI-functionalized biopolymers or prepolymers.

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Photocatalytic Reduction of CO2 to Methanol Using a Copper-Zirconia Imidazolate Framework

Catalysts ◽

10.3390/catal11030346 ◽

2021 ◽

Vol 11 (3) ◽

pp. 346

Author(s):

Sonam Goyal ◽

Maizatul Shima Shaharun ◽

Ganaga Suriya Jayabal ◽

Chong Fai Kait ◽

Bawadi Abdullah ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Catalyst Support ◽

Oxidation Potential ◽

Molar Ratio ◽

X Ray Diffraction ◽

X Ray ◽

Molar Ratios ◽

Optimum Parameters ◽

Reduction Of Co2 ◽

Enhanced Yield

A set of novel photocatalysts, i.e., copper-zirconia imidazolate (CuZrIm) frameworks, were synthesized using different zirconia molar ratios (i.e., 0.5, 1, and 1.5 mmol). The photoreduction process of CO2 to methanol in a continuous-flow stirred photoreactor at pressure and temperature of 1 atm and 25 °C, respectively, was studied. The physicochemical properties of the synthesized catalysts were studied using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectroscopy. The highest methanol activity of 818.59 µmol/L.g was recorded when the CuZrIm1 catalyst with Cu/Zr/Im/NH4OH molar ratio of 2:1:4:2 (mmol/mmol/mmol/M) was employed. The enhanced yield is attributed to the presence of Cu2+ oxidation state and the uniformly dispersed active metals. The response surface methodology (RSM) was used to optimize the reaction parameters. The predicted results agreed well with the experimental ones with the correlation coefficient (R2) of 0.99. The optimization results showed that the highest methanol activity of 1054 µmol/L.g was recorded when the optimum parameters were employed, i.e., stirring rate (540 rpm), intensity of light (275 W/m2) and photocatalyst loading (1.3 g/L). The redox potential value for the CuZrIm1 shows that the reduction potential is −1.70 V and the oxidation potential is +1.28 V for the photoreduction of CO2 to methanol. The current work has established the potential utilization of the imidazolate framework as catalyst support for the photoreduction of CO2 to methanol.

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