Ni-Fe Cocatalysts on Magnesium Silicate Supports for the Depolymerization of Kraft Lignin.

This research aimed to synthesize magnesium silicate (MgSiO3) used as a support for Ni-Fe cocatalysts in the depolymerization of kraft lignin. Magnesium silicate was prepared by a hydrothermal method, followed by metal solution impregnation to obtain lignin depolymerization catalysts. The catalytic efficiency of kraft lignin depolymerization to valued phenolic compounds was studied by varying the ratios of Ni and Fe on the MgSiO3 support. Moreover, other factors such as temperature, reaction time, and catalyst recycling affected both the quality and quantity of the products studied. The results illustrated that the catalyst 10Ni10Fe/MS produced all lignin depolymerization products with the highest yield (14.29 wt %) using reaction conditions of 300 °C and 1 h. In addition, the main products were found to be catechol (11.38 wt %), guaiacol (1.51 wt %), and phenol (0.79 wt %). More importantly, the 10Ni10Fe/MS catalyst showed good reusability even after two recycling processes, and the obtained phenol and guaiacol were found to be 0.63 and 1.01 wt %, respectively.

Golden Glittering Biocomposite Fibers from Poly(lactic acid) and Nanosilver-Coated Titanium Dioxide with Unique Properties; Antimicrobial, Photocatalytic, and Ion-Sensing Properties.

Golden glittering biocomposite fibers from poly(lactic acid) (PLA) and nanosilver-coated titanium dioxide (Ag/TiO2) were successfully prepared via a melt spinning process. Various contents of 10% Ag/TiO2/PLA masterbatch were diluted with PLA in concentrations of 5, 10, 15, 20, 25, and 30 phr, respectively. The physical, mechanical, thermal, and antibacterial properties of the obtained fibers were investigated. The results indicated that the glittering biocomposite fiber had a light, yellow-gold color and a slightly rough surface. Tenacity and elongation at break of the glittering biocomposite fibers were lower than those of the pristine PLA fiber. The thermal properties of the glittering composite fibers also decreased with increasing masterbatch content. The PLA/PEG-10 biocomposite fiber with good spinnability and mechanical properties was suitably used for preparing the golden glittering composite fabric by the knitting process. Moreover, the golden glittering biocomposite fabrics exhibited antibacterial activity against certain microbes, for example, Staphylococcus aureus, Bacillus subtilis, and Candida albicans. The prepared fabric has significant potential for use in eco-friendly textile products and antibacterial fabrics. Besides, our novel textiles showed not only the photocatalytic property needed to degrade organic dyes such as methylene blue in water but also the ion-sensing property for mercury(II) ions by changing the textile color from yellow to colorless.

Crystal structure and Hirshfeld surface analysis of the product of the ring-opening reaction of a di-hydro-benzoxazine: 6,6'-[(cyclo-hexyl-aza-nedi-yl)bis-(methyl-ene)]bis-(2,4-di-methyl-phenol).

In the title unsymmetrical tertiary amine, C24H33NO2, which arose from the ring-opening reaction of a di-hydro-benzoxazine, two 2,4-di-methyl-phenol moieties are linked by a 6,6'-(cyclo-hexyl-aza-nedi-yl)-bis-(methyl-ene) bridge: the dihedral angle between the dimethyl-phenol rings is 72.45 (7)°. The cyclo-hexyl ring adopts a chair conformation with the exocyclic C-N bond in an equatorial orientation. One of the phenol OH groups forms an intra-molecular O-H⋯N hydrogen bond, generating an S(6) ring, and a short intra-molecular C-H⋯O contact is also present. In the crystal, O-H⋯O hydrogen bonds link the mol-ecules into C(10) chains propagating along the [100] direction. The Hirshfeld surface analysis of the title compound confirms the presence of these intra- and inter-molecular inter-actions. The corresponding fingerprint plots indicate that the most significant contacts in the crystal packing are H⋯H (76.4%), H⋯C/C⋯H (16.3%), and H⋯O/O⋯H (7.2%).

4,4'-Diethyl-2,2'-[(N-cyclo-hexyl-imino)-bis-(methyl-ene)]diphenol.

The title compound, C(24)H(33)NO(2), exhibits an intra-molecular hydrogen bond between a phenol -OH group and the N atom. In the crystal, mol-ecules are connected by pairs of O-H⋯O hydrogen bonds.

4,4'-Dimeth-oxy-2,2'-[methyl-aza-ne-diyl-bis(methyl-ene)]diphenol.

The title compound, C(17)H(21)NO(4), shows an intra-molecular hydrogen bond between a phenol OH group and the N atom. In the crystal, mol-ecules are connected by pairs of O-H⋯O hydrogen bonds into inversion dimers.

2-{[(2-Hy-droxy-3,5-dimethyl-benz-yl)(meth-yl)amino]-meth-yl}-4,6-dimethyl-phenol.

In the title compound, C(19)H(25)NO(2), the dihedral angle between the benzene rings is 53.15 (8)°. One of the -OH groups forms an intra-molecular O-H⋯N link, generating an S(6) ring. The other -OH group forms an inter-molecular O-H⋯N hydrogen bond in the crystal, generating centrosymmetric R(2) (2)(20) loops.

The effect of alkali and Ce(III) ions on the response properties of benzoxazine supramolecules prepared via molecular assembly.

A series of benzoxazine monomer supramolecules with different substituted groups on their benzene ring was prepared with a Mannich reaction and characterized by FTIR, 1H-NMR and MS. The obtained products were 3,4-dihydro-3-(2'-hydroxyethylene)-6-methyl-2H-benzoxazine (BM1), 3,4-dihydro-3-(2'-hydroxyethylene)-6-ethyl-2H-benz-oxazine (BM2), and 3,4-dihydro-3-(2'-hydroxyethylene)-6-methoxy-2H-benzoxazine (BM3). The efficiency of alkali metal ion extraction from the products was determined with Pedersen's technique, while the complexation of the Ce(III) ion was confirmed by the Job's and the mole ratio methods. The evidence of complex formation between benzoxazine monomers and Ce(III) ions was obtained with FTIR and a computational simulation. Single phase ceria (CeO2) as observed with XRD was successfully prepared by calcinating the Ce(III)-benzoxazine monomer complexes at 600 °C for 2 h. In addition, the geometry of the ceria nanoparticles confirmed by TEM is spherical, with an average diameter of 10-20 nm.

Novel recovery of nano-structured ceria (CeO(2)) from Ce(III)-benzoxazine dimer complexes via thermal decomposition.

N,N-bis(2-hydroxybenzyl)alkylamines, benzoxazine dimers, are the major product produced from benzoxazine monomers on mono-functional phenol by the one step ring opening reaction. Due to the metal responsive property of benzoxazine dimers, in this present work, N,N-bis(5-methyl-2-hydroxybenzyl)methylamine (MMD), N,N-bis (5-ethyl-2-hydroxybenzyl)methylamine (EMD), and N,N-bis(5-methoxy-2-hydroxybenzyl) methyl amine (MeMD), are considered as novel ligands for rare earth metal ion, such as cerium(III) ion. The complex formed when the clear and colorless solutions of cerium nitrate and benzoxazine dimers were mixed, results in a brown colored solution. The metal-ligand ratios determined by the molar ratio and the Job's methods were found to be in a ratio of 1:6. To clarify the evidence of the complex formation mechanism, the interactions among protons in benzoxazine dimers both prior to and after the formation of complexes were determined by means of (1)H-NMR, 2D-NMR and a computational simulation. The single phase ceria (CeO(2)) was successfully prepared by thermal decomposition of the Ce(III)-benzoxazine dimer complexes at 600 °C for 2 h, was then characterized using XRD. In addition, the ceria powder investigated by TEM is spherical with an average diameter of 20 nm.