Microbial desulphurization of coal containing pyritic sulphur in a continuously operated bench scale coal slurry reactor

Pre-combustion microbial desulphurization of coal containing total sulphur (3.90%) and pyritic sulphur (2.80%) has been evaluated in a coal slurry reactor. The coal slurry reactor operated at hydraulic retention time (HRT) of 96 h with a coal pulp density of 15 percent and remove 79 percent of pyritic sulphur and 76 percent of ash with an increase in the calorific value of coal from 4400 to 6800 kcal kgK1 at a pyritic load of 1.9 kg pyritic sulphur kgK1 MLSS dK1. The treated coal yield is 72 percent. The biochemical kinetic coefficients, viz. yield coefficient (Y) and decay coefficient (Kd) in the coal slurry reactor system are 0.178 and 0.007 dK1, respectively, while maximum growth rate (mmax) and half saturation rate constant (Ks) are 0.025 hK1 and 0.220 g lK1 as pyrite, respectively

Click chemistry stereolithography for soft robots that self-heal

Although soft robotics promises a new generation of robust, versatile machines capable of complex functions and seamless integration with biology, the fabrication of such soft, three dimensional (3D) hierarchical structures remains a significant challenge.</p

Secondary Interactions Arrest the Hemiaminal Intermediate To Invert the <i>Modus Operandi</i> of Schiff Base Reaction: A Route to Benzoxazinones

Discovered by Hugo Schiff, condensation between amine and aldehyde represents one of the most ubiquitous reactions in chemistry. This classical reaction is widely used to manufacture pharmaceuticals and fine chemicals. However, the rapid and reversible formation of Schiff base prohibits formation of alternative products, of which benzoxazinones are an important class. Therefore, manipulating the reactivity of two partners to invert the course of this reaction is an elusive target. Presented here is a synthetic strategy that regulates the sequence of Schiff base reaction via weak secondary interactions. Guided by the computational models, reaction between 2,3,4,5,6-pentafluoro-benzaldehyde with 2-amino-6-methylbenzoic acid revealed quantitative (99%) formation of 5-methyl-2-(perfluorophenyl)-1,2-dihydro-4H-benzo­[d]­[1,3]­oxazin-4-one (<b>15</b>). Electron donating and electron withdrawing <i>ortho</i>-substituents on 2-aminobenzoic acid resulted in the production of benzoxazinones <b>9</b>–<b>36</b>. The mode of action was tracked using low temperature NMR, UV–vis spectroscopy, and isotopic (¹⁸O) labeling experiments. These spectroscopic mechanistic investigations revealed that the hemiaminal intermediate is arrested by the hydrogen-bonding motif to yield benzoxazinone. Thus, the mechanistic investigations and DFT calculations categorically rule out the possibility of <i>in situ</i> imine formation followed by ring-closing, but support instead hydrogen-bond assisted ring-closing to prodrugs. This unprecedented reaction represents an interesting and competitive alternative to metal catalyzed and classical methods of preparing benzoxazinone