Tribochemical behaviour and lubrication characteristics of aromatic compounds

Radical scavenger, radical anion scavenger, and peroxide decomposer were added to aromatic hydrocarbons and phosphates in aromatic rings with and without side chain, and the effect of these inhibitors on tribopolymerisation and the lubrication characteristics of the aromatic compounds were investigated, in various atmospheres, in order to clarify the reaction mechanism. The aromatics of both hydrocarbons and phosphates with a methyl group in aromatic rings react readily at the rubbing surfaces to form polymer or polymer-like products, improving the lubricating characteristics. The tribochemical reactions of alkylaromatic compounds is shown to differ from those of trialkyl or triarylphosphates. It was concluded that the reaction proceeds through the radical or radicalanion and via peroxide to cause polymerisation.     

Seismic proof test of a reinforced concrete containment vessel (RCCV): Part 2: Results of shaking table tests

A 1/8-scale model was constructed of a reinforced concrete containment vessel (RCCV) used in the latest advanced boiling water reactors (ABWR). Shaking table tests were conducted on it with input motions corresponding to or exceeding a design earthquake assumed for a real Nuclear Power Plant.The objectives of the tests were to verify the structural integrity and the leak-proof functional soundness of the RCCV subjected to design earthquakes, and to determine the ultimate strength and seismic margin by an excitation that led to the model's collapse. The model, the test sequence and the pressure and leak test results were addressed in Part 1. The shaking table test method, the input motions and the test results, including the transition of the model's stiffness, natural frequencies and damping factors and the effects of vertical input motions and internal pressure on the model's characteristics and behavior, the load–deformation, the ultimate strength, the failure mode of the reinforced concrete portion and the liner plate are described here. The seismic safety margin that was evaluated by the energy input during the failure test to a design basis earthquake will be described in Part 3. The analytical results of simulation using the multi-lumped mass model will be described in Part 4.     

The Potential Roles of Dec1 and Dec2 in Periodontal Inflammation

Periodontal inflammation is a common inflammatory disease associated with chronic inflammation that can ultimately lead to alveolar attachment loss and bone destruction. Understanding autophagy and pyroptosis has suggested their significant roles in inflammation. In recent years, studies of differentiated embryo-chondrocyte expressed genes 1 and 2 (Dec1 and Dec2) have shown that they play important functions in autophagy and in pyroptosis, which contribute to the onset of periodontal inflammation. In this review, we summarize recent studies on the roles of clock genes, including Dec1 and Dec2, that are related to periodontal inflammation and other diseases.     

Asymmetric organocatalysis of structurally well-defined chiral quaternary ammonium fluorides

Unique organocatalysis of both naturally occurring cinchona alkaloid-derived and purely synthetic chiral quaternary ammonium fluorides in synthetically useful stereoselective bond-forming reactions is overviewed. The development of this chemistry was initiated by the in situ generation of generally hygroscopic ammonium fluorides from the corresponding easy-to-handle ammonium salts in the presence of excess metal fluorides and their direct use for subsequent enantioselective reactions. On the other hand, chiral ammonium fluorides have been prepared by using ion-exchange resins and successfully applied as catalyst to various asymmetric bond formation reactions under homogeneous conditions. In addition, utilization of chiral quaternary ammonium bifluorides as organocatalysts in asymmetric synthesis is described, featuring their characteristic reactivity and selectivity.     

Ethanolamine Is a New Anti-Prion Compound

Prion diseases are a group of fatal neurodegenerative disorders caused by accumulation of proteinaceous infectious particles, or prions, which mainly consist of the abnormally folded, amyloidogenic prion protein, designated PrP^Sc. PrP^Sc is produced through conformational conversion of the cellular isoform of prion protein, PrP^C, in the brain. To date, no effective therapies for prion diseases have been developed. In this study, we incidentally noticed that mouse neuroblastoma N2a cells persistently infected with 22L scrapie prions, termed N2aC24L1-3 cells, reduced PrP^Sc levels when cultured in advanced Dulbecco’s modified eagle medium (DMEM) but not in classic DMEM. PrP^C levels remained unchanged in prion-uninfected parent N2aC24 cells cultured in advanced DMEM. These results suggest that advanced DMEM may contain an anti-prion compound(s). We then successfully identified ethanolamine in advanced DMEM has an anti-prion activity. Ethanolamine reduced PrP^Sc levels in N2aC24L1-3 cells, but not PrP^C levels in N2aC24 cells. Also, oral administration of ethanolamine through drinking water delayed prion disease in mice intracerebrally inoculated with RML scrapie prions. These results suggest that ethanolamine could be a new anti-prion compound.     

Improved heat and solvent resistance of a pressure‐sensitive adhesive thermally processable by isocyanate dimer dissociation

Methods that do not involve use of an organic solvent are being considered for manufacturing environmental‐friendly pressure‐sensitive adhesive tapes. Among these methods, the hot‐melt method exhibits high productivity but is somewhat limited in terms of performance. Hot‐melt‐fabricated pressure‐sensitive adhesives require heating fluidization and cooling solidification, and it is extremely difficult to improve their heat resistance. We examine thermally processable pressure‐sensitive adhesives with a completely new structure, fabricated based on the thermal dissociation of the isocyanate dimer. This enables thermal processing of materials softened by thermal dissociation. Fabrication of crosslinkable pressure‐sensitive adhesive becomes possible through a reaction of isocyanate caused by dissociation of its dimer. It is found that improving thermal and solvent resistances, which are disadvantages associated with conventional hot‐melt pressure‐sensitive adhesives, is potentially possible with the pressure‐sensitive adhesive reported here. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41444.     

Synthesis of AlPO4 Molecular Sieves with AFI and AEL Structures by Dry-Gel Conversion Method and Catalytic Application of Their SAPO Counterparts on Isopropylation of Biphenyl

AlPO₄-5 and AlPO₄-11 were synthesized by dry-gel conversion (DGC) method. Steam-assisted conversion (SAC) and vapor-phase transport (VPT) techniques were applied for this purpose. The synthesis was successful in presence of a certain minimum amount of external bulk water, without which the crystallization failed. Crystallization by VPT method was slower than corresponding SAC and HTS method. SAPO analogs of the samples, SAPO-5 and SAPO-11 were also synthesized by DGC method. Samples made by DGC methods had higher yield than the conventional hydrothermal synthesis (HTS); otherwise the samples showed similar characteristics as that made by HTS. XRD, SEM and N₂-adsorption results showed high crystallinity and purity of the samples made by DGC, and ²⁷Al MAS NMR spectra indicated the tetrahedral framework nature of Al. SAPO-5 and SAPO-11 were tested for their catalytic activity in isopropylation of biphenyl, and in terms of conversion and selectivity, SAPO-5 was found to be suitable for this application.     

Reforming of Methane with Carbon Dioxide over a Catalyst Consisting of Ruthenium Metal and Cerium Oxide Supported on Mordenite

Reforming of CH₄ with CO₂ proceeds at 400 °C over a catalyst consisting of ruthenium metal and CeO₂ highly dispersed on mordenite. The catalyst, Ru-CeO₂/MZ, is highly active for the reforming of CH₄ under the conditions at which a carbon formation reaction is thermodynamically apt to take place. The reforming selectively forms H₂ and CO. An increase in the weight of the catalyst resulting from carbon deposits was scarcely observed. IR spectra for the catalyst indicate that the reforming proceeds via the formation of the intermediate species such as Ru-CO and Ru-CH_x on the surface of ruthenium. The data of H₂ adsorption support the idea that ruthenium is highly dispersed in Ru-CeO₂/MZ.     

Organic–silicate hybrid catalysts based on various defined structures for Knoevenagel condensation

Two types of organic–inorganic hybrid base catalysts are prepared. Organic-functionalized molecular sieves (OFMSs), particularly “amine-immobilized porous silicates”, are designed based on common idea to immobilize catalytic active sites on silicate surface. Silicate–organic composite materials (SOCMs), such as “ordered porous silicate–quaternary ammonium composite materials”, are the precursors of ordered porous silicates obtained during the synthesis. Both the OFMS and the SOCM are used as the catalysts for Knoevenagel condensation. Among the OFMSs, there is clear tendency that the use of molecular sieve with larger pore volume and/or surface area gives the product in higher yield. Aminopropylsilyl (AP)-functionalized mesoporous silicates such as AP-MCM-41 gives the product in high yield under mild conditions. No loss of activity is observed after repeated use for three times. The SOCMs are also active for the same reaction. The precursors of the mesoporous silicates are more active than those of microporous silicates. This material can be repeatedly used without significant loss of activity. High activity is not due to the leached species. The active sites of the SOCM catalysts are considered to be SiO⁻ moieties located on the pore-mouth. Activity of the SOCM increases when the reaction is carried out without solvent, whereas decrease in activity of the OFMS is observed in the solvent-free system.     

The Roles of 3- and 4-Isopropylbiphenyls in the Isopropylation of Biphenyl over a H-Mordenite

The isopropylation of mixtures of 3- and 4-isopropylbiphenyls (3- and 4-IPBPs) was examined over a dealuminated H-mordenite (HM) to elucidate the role of 3- and 4-IPBPs in the isopropylation of biphenyl (BP). 4-IPBP was consumed much faster than 3-IPBP in all cases. 4-IPBP was an exclusive precursor to diisopropylbiphenyls (DIPBs), particularly 4,4-DIPB, and 4,4-DIPB was found in encapsulated products during the reaction. These results show that 4-IPBP can allow establishment of an active complex with propylene and acid site in HM pores, whereas 3-IPBP cannot. It is concluded that the isopropylation of BP over HM occurs through a reactant selectivity mechanism, and through a restricted transition state mechanism, but not through a product selectivity mechanism.