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Waterborne Polyurethanes for Packing Industries
Published in Ram K. Gupta, Ajay Kumar Mishra, Eco-Friendly Waterborne Polyurethanes, 2022
Saima Zulfiqar, Rida Badar, Muhammad Yar
Different ways are introduced by Lei and co-workers to prepare several WPU dispersions. These dispersions showed useful potential application for inks. Diethylenetriamine, tri-ethylene tetramine, and ethylenediamine were used as post chain extenders and perform various functions. The synthesis of WPU dispersions was modified to increase the water resistance by crosslinking of prepolymers. The resulting product was made compatible with waterbone ink binders and organic solvents without being removed. The printing process using the slow drying speed of water-based inks showed limited application with WPUs due to its use in small-scale printing industries. The thickness of WPU can be enhanced by the addition of solid content, which is the ultimate solution to minimize this problem. Vegetable oil-based hyperbranched polymers are preferred over linear polymers to get improved material properties and the advantage of green.
Advanced Technologies for the Removal of Refractory Contaminants from Pulp and Paper Mill Wastewater
Published in Maulin P. Shah, Removal of Refractory Pollutants from Wastewater Treatment Plants, 2021
The non-chlorinated compounds generated from the P&P industry include fatty acids, tannins, resin acids, diterpene alcohol, and steroids. The resin acids are diterpenoids which are released in higher amounts during the pulping process mainly by mechanical pulp production including dehydroabietic acids, abietic, palustic, levopimaric, and neoabietic. Due to the stable structure of resin acids, they cannot be degraded by the chemical degradation process and thus will contribute to the toxic levels of effluents ending up in the water bodies near P&P mills. Diethylenetriamine penta-acetic acid (DTPA) and ethylenediamine tetra-acetic acid (EDTA) are chelating agents which are mostly used for the ozone and peroxide bleaching of pulp. These are large organic molecules that can bind to metals. The chelating agents are discharged from P&P mills after the bleaching process and are found to be either completely resistant to degradation or undergo a slow degradation process. It was observed that bleach liquor with chelating agents when discharged may avoid the sedimentation of metals and thus result in the spreading of metals over a larger surface area.
Selective Catalytic Synthesis of Mixed Alkylamines and Polyfunctional Amines
Published in Dale W. Blackburn, Catalysis of Organic Reactions, 2020
Michael E. Ford, Thomas A. Johnson
In the phosphate-catalyzed route to polyethylene amines, ethanolamine alkylates ammonia or a lower amine to form the next higher homolog (Scheme 4). Owing to the relatively low nucleophilicity of ammonia, formation of ethylenediamine by reaction of ammonia with ethanolamine is significant only at high pressure (>1000 psig). Reaction of ethanolamine with ethylenediamine forms diethylenetriamine. Chain extension of diethylenetriamine occurs at both the primary and secondary amines to form linear and branched tetramines. Further reaction leads to linear and branched pentamines and higher polyethylene amines. In agreement with our results on the synthesis of functionalized amines with strontium hydrogen phosphate, deaminative cyclization, e.g., of diethylenetriamine to piperazine, is not observed at temperatures below 275°C.
Review: from computational design to the synthesis of molecular magnetic wires for single-molecule spintronics and quantum computing nanotechnologies†
Published in Journal of Coordination Chemistry, 2022
Consuelo Yuste, María Castellano, Jesús Ferrando-Soria, Salah-Eddine Stiriba, Nadia Marino, Miguel Julve, Francesc Lloret, Rafael Ruiz-García, Joan Cano
When using diethylenetriamine (dien) as a tridentate blocking ligand, Julve et al. were able to isolate and characterize a related pair of pyrazine (pyz) and 4,4′-bipyridine (4,4′-bpy)-bridged dinuclear copper(II) complexes of general formula [{CuII(dien)}2(µ-L)](ClO4)4 (L = pyz and 4,4′-bpy), as illustrated in Scheme 1 [3]. Despite the relatively large intermetallic separation across the pyz and 4,4′-bpy bridges (r = 6.8 and 11.1 Å, respectively), they exhibit a weak (J = −2.8 cm−1) to almost negligible antiferromagnetic coupling (J = −0.1 cm−1) [the spin Hamiltonian being defined as H = –JS1 ⋅ S2 (S1 = S2 = SCu = 1/2)]. In both cases, the magnetic coupling is mainly transmitted through the σ-bonds of the extended organic bridge, with little or no contribution from the π-bond system. The equatorial plane of the square pyramidal CuII ions is almost coplanar to the mean plane of the organic bridging ligand, and then the coordination bonds involve the sp2-type orbitals of the nitrogen atoms mixed with the px/py-type orbitals of the carbon atoms (Scheme 1, bottom). The overall coplanar disposition allows for propagation of the magnetic interactions between the two unpaired electrons occupying the d(x2-y2)-type orbitals (so-called “magnetic orbitals”) of each square pyramidal CuII across the polyazine bridge.
Tetraethylenepentamine modified magnetic cellulose nanocrystal composites for removal of Congo red with high adsorption capacity
Published in Journal of Dispersion Science and Technology, 2022
Dongqing Zhao, Lijuan Zhang, Yao Lu, Haotian Li, Saiqi Wang, Haikuan Yuan, Xijian Liu, Chengyin Wang, Xueyan Zhu, Jie Lu
However, CNC has fewer species of functional groups, and it is hard to be reused, which limited its practical application in the process of dyeing wastewater treatment. Therefore, a great deal of work has been processed to modify CNC with various materials rich in functional groups and rigid magnetic core to break those restrictions.[14,15] For instance, Ting-guo Yan et al.[16] dealt with the Fe3O4 by amino via a two-step process and the highest adsorption amount of CR was found to be 118.8 mg g−1. Fan Wang et al.[9] added magnetic cores inside the nanospheres and synthesized Fe3O4@SiO2@CS-TETA nanoparticles, after six times of re-adsorption, the adsorption capacity was 81.1% of the original. Due to the presence of amino, the adsorption capacity was also greatly increased. Jun-xia Yu et al.[17] found that it wasn’t the more amino, the larger amount of CR was adsorbed. Due to the steric hindrance effect, TEPA adsorbed the most CR in some substances with different amino contents (ethylenediamine, diethylenetriamine, tetraethylenepentamine), and the adsorption capacity was approximately 780 mg g−1. However, these works still suffered from low absorption capacity. In order to solve this problem, recent researches show that the CNC with TEPA rich in amino would improve the absorption capacity remarkably.[18,19]
Synthesis, spectroscopic characterization, computational studies, theoretical investigation of NLO properties and antibacterial activities of mixed ligand complexes of Co(II) and Cu(II)
Published in Journal of Coordination Chemistry, 2021
Vishnu Kumar Modanawal, Sikandar Paswan, Afreen Anjum, Manoj Kumar, Shekhar Srivastava, Nitesh Jaiswal
Our continuous interest in Schiff base metal complexes of biological potential [23–26] catalyzed us to explore mixed ligand complexes of cobalt and copper. The present work deals with the synthesis of p-dimethylaminobenzaldehyde Schiff base ligand 2-(4-(dimethylamino)benzylideneamino)phenol and their Co(II) and Cu(II) complexes containing ethylenediamine or diethylenetriamine moiety. These complexes were characterized by UV-vis, FT-IR, ESI-MS, PXRD and ESR analysis. The nonlinear optical properties of the Schiff base DBAP and mixed ligand complexes were examined theoretically. The computational calculations of ligand and complexes were also carried out using density functional method. The biological activities of ligand and complexes were evaluated against V. cholerae and E. coli strains.