Cellulose was extracted from brewer's spent grain (BSG) by alkaline and bleaching treatments. The extracted cellulose was used in the preparation of carboxymethyl cellulose (CMC) by reaction with monochloroacetic acid in alkaline medium with the use of a microwave reactor. A full-factorial 2(3) central composite design was applied in order to evaluate how parameters of carboxymethylation process such as reaction time, amount of monochloroacetic acid and reaction temperature affect the average degree of substitution (DS) of the cellulose derivative. An optimization strategy based on response surface methodology has been used for this process. The optimized conditions to yield CMC with the highest DS of 1.46 follow: 5g of monochloroacetic acid per gram of cellulose, reaction time of 7.5min and temperature of 70°C. This work demonstrated the feasibility of a fast and efficient microwave-assisted method to synthesize carboxymethyl cellulose from cellulose isolated of brewer's spent grain.

NMR chemical shifts have been experimentally measured and theoretically estimated for all the carbon atoms of (1R,3S,4S,8S)-p-menthane-3,9-diol in chloroform solution. Theoretical estimations were performed using a combination of molecular dynamics simulations and quantum mechanical calculations. Molecular dynamics simulations were used to obtain the most populated conformations of the (1R,3S:4S,8S)-p-menthane-3,9-diol as well as the distribution of the solvent molecules around it. Quantum mechanical calculations of NMR chemical shifts were performed on the most relevant conformations employing the GIAO-DFT formalism. A special emphasis was put in evaluating the effects of the surrounding solvent molecules. For this purpose, supermolecule calculations were performed on complexes constituted by the solute and n chloroform molecules, where n ranges from 3 to 16. An excellent agreement with experimental data has been obtained following this computational strategy.

Mechanochemistry is an alternative for sustainable solvent-free processes that has taken the big step to become, in the near future, a useful synthetic method for academia and the fine chemical industry. The apparatus available, based on ball milling systems possessing several optimizable variables, requires too many control and optimization experiments to ensure reproducibility, which has limited its widespread utilization so far. Herein, we describe the development of an automatic mechanochemical single-screw device consisting of an electrical motor, a drill, and a drill chamber. The applicability and versatility of the new device are demonstrated by the implementation of di- and multicomponent chemical reactions with high reproducibility, using mechanical action exclusively. As examples, chalcones, dihydropyrimidinones, dihydropyrimidinethiones, pyrazoline, and porphyrins, were synthesized with high yields. The unprecedented sustainability is demonstrated by comparison of EcoScale and E-factor values of these processes with those previously described in the literature.

Water, under microwave irradiation and at a temperature of 473 K, reaches pressures above 16 bar, being capable to act as catalyst, without the use of organic solvents and oxidants, for meso-substituted porphyrin synthesis. Sustainability of the reaction is proved by E Factor=35 and EcoScale value of 50.5, the highest so far obtained for porphyrin synthesis. Methodology's wide versatility is clearly demonstrated by the good yields obtained for both aryl and alkyl substituted porphyrins. These reaction conditions represent a huge development, not only by using very high concentrations, minimizing organic solvent usage, but also by eradicating toxic expensive solvents and oxidants.

Crystalline systems can be organized from several types of intermolecular interactions, among which classical and weak H-bonds are the most common, playing a very important role in the supramolecular assembly. However, in recent years a number of works have considered the influence of the homonuclear dihydrogen interaction, which had been neglected for a long time, to describe the supramolecular assembly of single crystals. In the C17H17N3O2 azine of the present study, a nonclassical dihydrogen interactions (C–H···H–C contact) have appeared in the crystal structure with a fundamental contribution toward the stability of crystalline packing. Nonetheless, an X-ray structural analysis is not conclusive to assess the real importance of the C–H···H–C contact. In order to characterize the nature and implications of C–H···H–C contacts concomitant with the classical interactions, the crystallized compound was evaluated by Hirshfeld surface, Quantum Theory of Atoms in Molecules, natural bond orbital, and Car–Parrinello molecular dynamics. The results establish that these interactions really exist, and their extension is responsible for the cooperative effect on the stability of crystalline packing. We expect that a more thorough understanding and description of homonuclear dihydrogen interactions in the supramolecular assembly of C17H17N3O2 can assist in the crystal engineering of small molecules, offering progress on physical–chemistry parameters of biological and material processes.

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Organic molecules with electron acceptors or withdrawal substituents terminal at π-conjugated system are promising candidates to be explored as materials with high linear and nonlinear optical properties. On the basis of these features, a novel asymmetric azine (7E, 8E)-2-(3-methoxy-4-hydroxy-benzylidene)-1-(4nitrobenzylidene)hydrazineC 15 H 13 N 3 O 4 (NMZ) was synthesized. The molecular structure of NMZ was elucidated by X-ray crystallography and the supramolecular arrangement was analyzed from Hirshfeld surface methodology. An iterative electrostatic scheme using a super molecule approach, where neighboring molecules are represented by charge points, was employed to investigate optical dipole moment (μ), the linear polarization (α) and the first (β) and second (γ) hyperpolarizabilities. The NMZ crystallized in the centrosymetric space group P2 1 /n and packs viaand N•••π interactions. The macroscopic property of third order χ (3) found for the NMZ is 298.62 times greater than values reported for chalcone derivative (2E)-1-(3-bromophenyl)-3-[4 (methylsulfanyl)phenyl]prop-2en-1-one. The results for NMZ indicate a good nonlinear optical effect.