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Direct, Discharge and Resist Styles of Printing
Published in Asim Kumar Roy Choudhury, Principles of Textile Printing, 2023
Stabilization may be done in two ways: Converting syndiazotate (coupling form) to antidiazotate (non-coupling form) by treating with exess caustic soda (Equation 5.4). Forming diazo-amino compound: Diazonium salt is treated with suitable amino compound to give non coupling diazoamino/diazoimino compound. These are stable under neutral and alkaline condition, but under acidic condition they split up, liberating coupling diazonium compound. Amino compounds used as stabilizer may be one of the following: 2-Amino-4-Sulphobenzoic acid: 2-Amino-4-Sulphobenzoic acid2-Methylamino-5-Sulphobenzoic acid: 2-Methylamino-5-Sulphobenzoic acidN-Methyl glycine (Sarcocine) CH3-NH-CH2-COOHMethyle taurine CH3NH-CH2-CH2SO3H2-Ethylamino-5-Sulphobenzoic acid
Symbols, Terminology, and Nomenclature
Published in W. M. Haynes, David R. Lide, Thomas J. Bruno, CRC Handbook of Chemistry and Physics, 2016
W. M. Haynes, David R. Lide, Thomas J. Bruno
Diazo compounds - Compounds having the divalent diazo group, =N+=N-, attached to a carbon atom, e.g., CH2=N2 diazomethane. [5] Dielectric constant ()* - Ratio of the electric displacement in a medium to the electric field strength. Also called permittivity. [1] Dienes - Compounds that contain two fixed double bonds (usually assumed to be between carbon atoms). Dienes in which the two double-bond units are linked by one single bond are termed conjugated. [5] Differential scanning calorimetry (DSC) - See Techniques for Materials Characterization, page 12-1. Differential thermal analysis (DTA) - See Techniques for Materials Characterization, page 12-1. Diffusion* - The migration of atoms, molecules, ions, or other particles as a result of some type of gradient (concentration, temperature, etc.). Diopter - A unit used in optics, formally equal to m-1. It is used in expressing dioptic power, which is the reciprocal of the focal length of a lens. Dipole moment, electric (p,µ)* - For a distribution of equal positive and negative charge, the magnitude of the dipole moment vector is the positive charge multiplied by the distance between the centers of positive and negative charge distribution. The direction is given by the line from the center of negative charge to the center of positive charge. Dipole moment, magnetic (m,µ) - Formally defined in electromagnetic theory as a vector quantity whose vector product with the magnetic flux density equals the torque. The magnetic dipole generated by a current I flowing in a small loop of area A has a magnetic moment of magnitude IA. In atomic and nuclear physics, a magnetic moment is associated with the angular momentum of a particle; e.g., an electron with orbital angular momentum l exhibits a magnetic moment of -el/2me where e is the elementary charge and me the mass of the electron. [1] Disaccharides - Compounds in which two monosaccharides are joined by a glycosidic bond. [5] Dislocation - An extended displacement of a crystal from a regular lattice. An edge dislocation results when one portion of the crystal has partially slipped with respect to the other, resulting in an extra plane of atoms extending through part of the crystal. A screw dislocation transforms successive atomic planes into the surface of a helix. Dispersion - Splitting of a beam of light (or other electromagnetic radiation) of mixed wavelengths into the constituent wavelengths as a result of the variation of refractive index of the medium with wavelength. Dissociation constant* - The equilibrium constant for a chemical reaction in which a compound dissociates into its constituent parts. Dissociation energy (De)* - For a diatomic molecule, the difference between the energies of the free atoms at rest and the minimum in the potential energy curve. The term bond dissociation energy (D0), which can be applied to polyatomic molecules as well, is used for the difference between the energies of the fragments resulting when a bond is broken and the energy of the original molecule in its lowest energy state. The term bond strength implies differences in enthalpy rather than energy.
Novel resources recovery from anaerobic digestates: Current trends and future perspectives
Published in Critical Reviews in Environmental Science and Technology, 2022
Paul Sebastian Selvaraj, Kalaiselvi Periasamy, Kathirvel Suganya, Kavitha Ramadass, Selvamurugan Muthusamy, Poornima Ramesh, Richard Bush, Salom Gnana Thanga Vincent, Thava Palanisami
Sludge based carbon (S@C) nanocomposites were prepared from dry sludge and glucose as the carbon source at different HTC temperatures (160 °C for 48 h, 180 °C for 48 h and 200 °C for 24 h) with and without FeSO4.7H2O. The resulting products were indicated as S@C160, S@C180, S@C200 and S@C and used as sorbents. These nanocomposites were used for treating arsenic-contaminated water. Nearly 100 per cent removal of As (V) was achieved within 0.5 h wherein the water contained 0.5 mg L−1 of As (V) at pH of 5 and 3.6 g L−1 concentration of Sludge@carbon nanocomposites (El-Deen & Zhang, 2012). Porous carbon from sewage sludge was prepared by microwave activation and carbonization (600 °C). It displayed a mesoporous structure with magnetic properties. Sludge-derived mesoporous carbon adsorbed (95.1 mg g−1) and degraded (94% at SC/15 mM H2O2) the 1-diazo-2-naphthol-4-sulfonic acid (1,2,4-acid) in the presence of H2O2. It was used for solid-liquid separation applications. Furthermore, SC had a co-catalytic effect on iron, carbon, silicon and aluminum, which increased the dispersion of catalytic centers and adsorbed the concentrated organic pollutants (Gu et al., 2013).
Rhodium catalysis in the synthesis of fused five-membered N-heterocycles
Published in Inorganic and Nano-Metal Chemistry, 2020
Navjeet Kaur, Neha Ahlawat, Yamini Verma, Pranshu Bhardwaj, Pooja Grewal, Nirmala Kumari Jangid
A carbon-hydrogen insertion product (81) was formed by the reaction of a diazo compound (78) with a carbon-hydrogen bond (present at a suitable position of diazo molecule) with the help of transition-metal catalyst. The intramolecular reaction of diazo compounds (78) containing a reactive C-H bond and one or more heteroatoms between a diazo group synthesized a new carbon-carbon bond via C-H insertion which led to heterocyclic compounds (81).[103–110] The nitrogen possessing heterocycle (81) was designed with high cis-diastereoselectivity in 78% yield by Rh2(4R-MPPIM)4 complex catalyzed reaction of the diazo ester (78). The turneforcidine (81) was constructed from nitrogen heterocycle under conventional conditions (Scheme 27).[13,111]
Reactions of thiocarbonyl compounds with electrophilic and nucleophilic carbenes as well as with their metal complexes
Published in Journal of Sulfur Chemistry, 2020
Grzegorz Mlostoń, Heinz Heimgartner
The intramolecular reactions of diazo compounds containing a thiocarbonyl moiety offer a convenient access to cyclic or polycyclic products with preservation or extrusion of the sulfur atom. In a pioneering work, Padwa described a protocol for the intramolecular formation of reactive thiocarbonyl ylides, which were efficiently trapped with common dipolarophiles such as N-phenylmaleimide or dimethyl acetylenedicarboxylate [36]. A representative example with diazo compound 84 and the polycyclic product 86 is depicted in Scheme 19. The intermediate thiocarbonyl ylide 85 was postulated as 1,3-dipole, which enter the [3 + 2]-cycloaddition with N-phenylmaleimide to give 86 in 75% yield. The intermediate thiocarbonyl ylide 85 is stabilized as a mesoionic system and reacts easily with the added dipolarophile.