Bio-Based Polyols from Seed Oils for Water-Blown Rigid Polyurethane Foam Preparation

The preparation of water-blown rigid polyurethane (RPUR) foams using bio-based polyols from sesame seed oil and pumpkin seed oil has been reported. Polyols synthesis involved two steps, namely, hydroxylation and alcoholysis reaction. FTIR, NMR, and ESI-MS were used to monitor the process of the synthesized polyols and their physicochemical properties were determined. The resulting polyols have OH number in the range of 340–351 mg KOH/g. RPUR foams blown with water were produced from the reaction of biopolyols with commercial polymeric methylene diphenyl diisocyanate (PMDI). The proper PUR formulations can be manipulated to produce the desired material applications. These seed oil-based RPUR foams exhibited relatively high compressive strength (237.7–240.2 kPa) with the density in the range of 40–45 kg/m3. Additionally, the cell foam morphology investigated by scanning electron microscope indicated that their cellular structure presented mostly polygonal closed cells. The experimental results demonstrate that these bio-based polyols can be used as an alternative starting material for RPUR production

3,3,6,6-Tetrakis­(hydroxy­meth­yl)-1,2,4,5-tetra­zinane tetra­hydrate

In the title compound, C6H16N4O4·4H2O, the tetra­zinane mol­ecule lies across an inversion centre. The tetra­zinane ring adopts a chair conformation, and all imino H atoms occupy axial positions. In the crystal, adjacent mol­ecules are linked through O—H⋯O, O—H⋯N and N—H⋯O hydrogen bonds with water mol­ecules generating a three-dimensional network

SYNTHETIC AND MECHANISTIC STUDIES ON THE ELECTROOXIDATION OF ORGANIC THIOETHERS.

This research has been directed at the study of neighboring group participation in electrooxidation of thioethers. Controlled potential oxidation of substituted 1,3-dithiane in wet acetonitrile provides substituted 1,2-dithiolane 1-oxide in good yield. Thioethers appended with neighboring alcohols and carboxylate are catalytically oxidized in a redox cycle by bromide ion. The formation of the alkoxysulfonium salt intermediates in such reactions is confirmed by product study. On the other hand, the acyloxysulfonium salt intermediates in the electrooxidation of endo -6-methylthio-bicyclo [2.2.1] heptane-2- endo -carboxylic acid (1) are unstable at room temperature. Control experiments using ¹⁸O labeled compounds prove unequivocally the existent of the acyloxysulfonium salt intermediates. Diastereospecific oxidation of 1 and its methyl ester with DABCO.2Br₂ complex and m-CPBA is sterically controlled. In both cases, similar product ratios are observed which is explained by the participation of the carboxylic acid group in the case of DABCO.2Br₂ oxidation but not in the case of m-CPBA oxidation. The structure of one of the diastereomer of the endo acid sulfoxide is unequivocally proved by x-ray crystallographic analysis

4-Amino-N-(2-hydroxy-4-pentadecylbenzylidene)benzenesulfonamide

4-Amino-N-(2-hydroxy-4-pentadecylbenzylidene)benzenesulfonamide has been synthesized by reaction of 2-hydroxy-4-pentadecylbenzaldehyde with 4-aminobenzenesulfonamide in the presence of acetic acid in ethanol. The structure of this new compound was confirmed by elemental analysis, IR, 1H-NMR, 13C-NMR and mass spectral analysis

4-[(2-Hydroxy-4-pentadecylbenzylidene)amino]-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one

Novel 4-[(2-hydroxy-4-pentadecylbenzylidene)amino]-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one was prepared via condensation of 2-hydroxy-4-pentadecylbenzaldehyde (1) with 4-amino-1,2-dihydro-2,3-dimethyl-1-phenylpyrazol-5-one (2) in ethanol/acetic acid under reflux. The structure of the synthesized compound was assigned on the basis of elemental analysis and spectral data

Activation of Cassava Stem Biochar by Physico-Chemical Method for Stimulating Cadmium Removal Efficiency from Aqueous Solution

Removal of Cadmium (Cd) from aqueous solution using biochar was considered a cost effective sorbent. Biochar quality and specification depend on its carbonization processes. In this study, the cassava stem biochars were produced at temperature of 300, 400 and 500 °C with slow pyrolysis technique. The biochar in each carbonization temperature was activated with physico-chemical treatments, pre-activated by 1.63M KOH solution then activated with second pyrolysis as same as first pyrolysis conditions. Adsorption study by using biochar adsorb Cd ion from Cd(NO3)2 solution by batch static method. The results indicated that the removal efficiency of activated biochar produced at pyrolysis temperature 300 °C can be increased from 10.46 to 24.88 mg/g and was selected for adsorption characteristic and biochar properties. Adsorption isotherm of non-activated and activated biochar were fitted both Langmuir and Freundlich isotherm (r2>0.95). The BET surface area of activated biochar was increased from 6.8818 to 9.4964 m2/g, while, pore size and chemical properties could be preserved. In summary, our results suggest that KOH pre-activated and second pyrolysis could increase Cd removal efficiency from aqueous solution