Effect of waste tires addition on a low-temperature hydrovisbreaking process of vacuum residue

Most of the resources used for energy have a fossil origin and they are non-renewable materials. Using mixtures of waste materials with the currently used non-renewable materials can improve the renewability of the energy production. The goal of this work was to explore the effect of waste tire addition on a hydrovisbreaking process at low temperature. Four tests were carried out at 300 °C in H₂ with different feedstocks: (1) vacuum residue; (2) tires; (3) 37.5wt% tires + 62.5wt% vacuum residue; (4) 15wt% tires + 85wt% vacuum residue. Dynamic viscosity, simulated distillation, density, elemental analysis (C, H, N, S% content) by ICP and analysis of gaseous products by GC–MS were carried out for all products. Content of insoluble compounds in hexane was estimated for the products from test (1) and vacuum residue. TGA analyses of the tires were carried out. The addition of tires to the vacuum residue brought a positive effect to increasing the yield of lighter products in the final liquid product. Densities and composition determinated by elemental analyses were similar for feedstock and products. The dynamic viscosity (60 °C) decreased from 24,550 to 17,700 mPa s for test (1) and to 1640 mPa s for test (3).     

Biomolecule-Assisted Synthesis of Hierarchical Multilayered Boehmite and Alumina Nanosheets for Enhanced Molybdenum Adsorption

The effective utilization of various biomolecules for creating a series of mesoporous boehmite (γ-AlOOH) and gamma-alumina (γ-Al₂O₃) nanosheets with unique hierarchical multilayered structures is demonstrated. The nature and concentration of the biomolecules strongly influence the degree of the crystallinity, the morphology, and the textural properties of the resulting γ-AlOOH and γ-Al₂O₃ nanosheets, allowing for easy tuning. The hierarchical γ-AlOOH and γ-Al₂O₃ multilayered nanosheets synthesized by using biomolecules exhibit enhanced crystallinity, improved particle separation, and well-defined multilayered structures compared to those obtained without biomolecules. More impressively, these γ-AlOOH and γ-Al₂O₃ nanosheets possess high surface areas up to 425 and 371 m² g⁻¹, respectively, due to their mesoporous nature and hierarchical multilayered structure. When employed for molybdenum adsorption toward medical radioisotope production, the hierarchical γ-Al₂O₃ multilayered nanosheets exhibit Mo adsorption capacities of 33.1–40.8 mg g⁻¹. The Mo adsorption performance of these materials is influenced by the synergistic combination of the crystallinity, the surface area, and the pore volume. It is expected that the proposed biomolecule-assisted strategy may be expanded for the creation of other 3D mesoporous oxides in the future.     

Vibrational Circular Dichroism Unravels Supramolecular Chirality and Hydration Polymorphism of Nucleoside Crystals

Vibrational circular dichroism (VCD) spectroscopy has been widely used to study (bio)molecules in solution. However, its solid-state applications have been restricted due to experimental limitations and artifacts. Having overcome some of them, the first VCD study of nucleoside crystals is now presented. A two-orders-of-magnitude enhancement of VCD signal was observed due to high molecular order in the crystals and resulting supramolecular chirality. This allowed to obtain high-quality VCD spectra within minutes using minute amounts of samples. The VCD technique is extremely sensitive in detecting changes in a crystal order and is able to distinguish different hydration states of crystals. This elevates it to a new level, as a fast and efficient tool to study chiral crystalline samples. This study demonstrates that VCD is capable of near-instantaneous detection of hydration polymorphs and crystal degradation, which is of substantial interest in pharmaceutical industry (quality and stability control).     

Mechanochemical Pretreatment for Efficient Solvent-Free Synthesis of SSZ-13 Zeolite

The economical and environmentally benign synthesis of SSZ-13 zeolite was possible due to the mechanochemical activation of dry reagents by planetary mill. Contrary to manual grinding in a mortar, the proposed automatized approach is scalable and reproducible. This solvent-free process provided a huge gain in product/gel ratios, significantly minimized reaction space and organic structure-directing agent use, and allowed for the elimination of agitation. Obtained materials were comparable to the product of “classical” syntheses. The use of different silica sources resulted in SSZ-13 zeolites with various characteristics: different Si/Al ratio and crystal size.     

Lithium salts of [1,12-dialkyl-CB11Me10]- anions

We report the syntheses of several [1-R-CB(11)-Me(11)](-) and [1-R-12-R'-CB(11)-Me(10)](-) anions (R, R' = alkyl) and the solubilities of their lithium salts in cyclohexane. These solutions are of interest as Lewis acid catalysts. The new anions are not directly accessible by methylation with methyl triflate because of intervening triflyloxy substitution on one or more boron vertices. The difficulty has been circumvented in two ways. Either (i) an iodo substituent is first introduced into position 12, permitting a clean decamethylation, and then replaced with a methyl by reaction with trimethylaluminum or (ii) the offending triflyloxy substituents are replaced with methyls by reaction with trimethylaluminum.     

Microwave-assisted alkylation of [CB11H12]- and related anions

A total of 19 permethylated derivatives of substituted [CB(11)H(12)](-) anions have been prepared using alkylation with microwave assistance. The reactions proceed much faster and more cleanly than under ordinary conditions. Microwave assistance is especially convenient for the permethylation of carborane anions carrying electron-withdrawing groups in positions 1 and/or 12. Even [1-F-CB(11)H(11)](-) can be undecamethylated, whereas under ordinary heating, it has only been hexamethylated.     

Electron Density Shift in Imidazolium Derivatives upon Complexation with Cucurbit[6]uril

In this study, we have investigated the supramolecular interaction between series of 1‐alkyl‐3‐methylimidazolium guests with variable alkyl substituent lengths and cucurbit[6]uril (CB6) in the solution and the solid state. Correct interpretation of ¹H NMR spectra was a key issue for determining the binding modes of the complexes in solution. Unusual chemical shifts of some protons in the ¹H NMR spectra were explained by the polarization of the imidazolium aromatic ring upon the complexation with the host. The formation of 1:1 complex between 1‐ethyl‐3‐methylimidazolium and CB6 is in disagreement with previously reported findings describing an inclusion of two guest molecules in the CB6 cavity.