Search results for "alloys"

Controlled orientation and alignment in films of halloysite nanotubes by liquid-crystalline processing

2014

Halloysite based material for enhanced solubilization

2014

GREEN CONDITIONS FOR THE SUZUKI REACTIONS BY USING MICROWAVE IRRADIATION AND MODIFIED HALLOYSITE/Pd CATALYST

2014

Halloysite nanotube (HNT) is an emerging biocompatible material with appealing perspective for technological applications, such as in catalysis1 and in pharmaceutical research.2 Halloysite is a double-layered aluminosilicate mineral that has a predominantly hollow tubular structure. The functionalization of HNTs is a good strategy to introduce an organic moiety onto the external surface and, therefore, to obtain innovative catalyst supports.3 We have modified the external surface of halloysite nanotube with octylimidazolium moieties (HNT-IL) by microwave irradiation in solvent-free conditions and we have have employed this material as support catalyst of Pd nanoparticles. The new HNT/Pd cat…

SYNTHESIS AND EVALUATION OF CATALYTIC ACTIVITY IN WATER AND MICROWAVE IRRADIATION OF A NEW SUPPORT BASED ON HNT TRIAZOLIUM SALTS

2014

In the last years SILLP (supported ionic liquid-like phase)-based materials prepared by covalent attachment have been synthesized [1]. Recently, we have synthesized a palladium-based catalytic system using halloysite nanotubes modified with octylimidazolium moieties and we have tested it in the Suzuki cross-coupling reaction under traditional heating, microwave irradiation and a very small amount of Pd catalyst [2,3]. It is known that support based on triazole motif showed superior activity to the analogous imidazole molecules [4] so, we have focused our attention to develop a new SILLP system with triazolium moiety. Herein we report the synthesis of an original Pd-dicationic triazolium sup…

Clay Nanotube/Perfluorinated Surfactant Hybrid Materials

2013

Clay Nanotube/PNIPAAM Hybrid material

2014

SYNTHESIS AND CHARACTERIZATION OF POSITIVELY CHARGED FUNCTIONALIZED HALLOYSITE/CURCUMIN SYSTEMS AND EVALUATION OF THEIR ANTICANCER ACTIVITY

2014

Phenolic compound originated from one of the main class of secondary metabolites, as curcumin and its derivatives have been studied and their biological and pharmacological activities have been evaluated, too [1,2]. Unfortunately, curcumin exhibits poor bioavailability after oral or topic administration [3]. Therefore a carefully designed carrier could significantly facilitate curcumin delivery and broaden the range of its possible pharmaceutical applications. Halloysite was found to be a viable and inexpensive nanoscale container for the encapsulation of biological active molecules [4]. In this communication we report data about a new potential curcumin carrier based on positively charged …

Very strong −N–X+⋯−O–N+ halogen bonds

2016

A new (-)N-X(+)(-)O-N(+) paradigm for halogen bonding is established by using an oxygen atom as an unusual halogen bond acceptor. The strategy yielded extremely strong halogen bonded complexes with very high association constants characterized in either CDCl3 or acetone-d6 solution by (1)H NMR titrations and in the solid-state by single crystal X-ray analysis. The obtained halogen bond interactions, RXB, in the solid-state are found to be in the order of strong hydrogen bonds, viz. RXB ≈ RHB.

Features of W production in p-p, p-Pb and Pb-Pb collisions

2017

We consider the production of inclusive W bosons in variety of high-energy hadronic collisions: p--p, p--$\overline{\rm p}$, p--Pb, and Pb--Pb. In particular, we focus on the resulting distributions of charged leptons from W decay that can be measured with relatively low backgrounds. The leading-order expressions within the collinearly factorized QCD indicate that the center-of-mass energy dependence at forward/backward rapidities should be well approximated by a simple power law. The scaling exponent is related to the small-$x$ behaviour of the quark distributions, which is largely driven by the parton evolution. An interesting consequence is the simple scaling law for the lepton charge as…

Reduction and catalytic behaviour of heterobimetallic copper–lanthanide oxides

2008

Abstract The reduction of the heterobimetallic copper–lanthanide oxides 2CuO·CeO2 and 3CuO·Ln2CuO4 (Ln = La, Pr, Nd) was studied by H2-TG/DTA and H2-TPR. All systems exhibit two main reduction steps accompanied by mass losses in the temperature range 20–1000 °C. The first step was attributed to CuO reduction, whereas the second step is due either to copper reduction in the Ln2CuO4 phase with the concomitant formation of Ln2O3 or to the surface reduction of CeO2. The products were characterized by XRD, SEM, EDX, and BET techniques and are better described as supported copper type materials. They were active for the mesityl oxide (4-methyl-2-penten-2-one) gas phase hydrogenation.