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Surface platinum of sulfated zirconia has been characterized by hydrogenation of toluene at 150°C and by carbon monoxide adsorption on a series of catalysts containing 0.025–0.8 wt% Pt. The variation of the hydrogenation rate with the Pt content showed two linear domains with a sharp increase at 0.15 wt% Pt. A very good correlation between hydrogenation activity and CO adsorption indicates that the low activity at low loading results from a lack of accessible platinum. We suggest that part of the platinum migrated to the subsurface of the zirconia matrix. After the saturation of the subsurface platinum sites, additional platinum is located on the surface with a constant particle size of about 1 nm. Combination of these results with those of the isomerization of n-hexane at 150°C indicates that very active surface platinum does not play the key role in isomerization. The influence of hydrogen on the isomerization activity nicely correlates with the estimated amount of platinum inserted in the subsurface of zirconia. Reduction of the catalysts at higher temperatures (up to 250°C) diminishes strongly the toluene hydrogenation activity of the samples, while n-hexane isomerization is hardly affected. This is further proof of the importance of subsurface platinum in isomerization and supports the kinetic model based on Lewis acid sites, where desorption of the isocarbenium ion is assisted by hydrides formed on subsurface platinum. [Copyright &y& Elsevier]

In this work, silica microcapsules containing phosphonium ionic liquid (IL), denoted SiO 2 @IL, were successfully synthesized for the first time using the one step sol-gel method in IL/H 2 0 emulsion. The morphologies of the obtained micron-size microcapsules, including their diameter distribution, were characterized using dynamic light scattering (DLS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The thermal behavior of these microcapsules and the mass fraction of the encapsulated IL in the silica microcapsules were determined using thermogravimetric analysis, showing an excellent thermal stability (up to 220 °C) and highlighting that an amount of 20 wt.% of IL is contained in the silica microcapsules. In a second step, SiO 2 @IL microcapsules (1 wt.%) were dispersed into epoxy-amine networks to provide proof of concept of the ability of such microcapsules to act as healing agents as microcracks propagate into the epoxy networks., Competing Interests: The authors declare no conflicts of interest.

Hydrogen bond mediated films made by step by step deposition of poly(4-vinylpyridine) (P4VP) and hydroxylated poly(2,3,4,5,6-pentafluorostyrene) (PPFS) copolymers prepared by thiol para-fluoro coupling, bearing either one (PPFSME) or two (PPFSMPD) hydrogenated hydroxyl groups or a (poly)fluorinated hydroxyl (PPFSOH), respectively, were successfully constructed. The influence of the structural parameters, such as the hydroxyl environment (which dictates the H-bond strength) was in-depth investigated in terms of their impact on (i) growth mechanism, (ii) internal organization, and (iii) surface features. The use of the weaker H-bond donor partner (PPFSME) leads to low quality films composed of irregularly distributed aggregates. While [PPFSMPD/P4VP] multilayer films are comparatively thick and composed of stratified layers with smooth topology, the use of PPFSOH with P4VP yields thin films made of mixed and interpenetrated polymer layers. Playing on the interaction strength appears as a powerful tool to elaborate tailored multilayer films with molecularly tunable properties.

The microstructure, thermal stability, surface energy, and swelling characteristics of two kinds of commercial organoclays, before and after washing treatment with a mixture of H2O/ethanol, were investigated using X-ray diffraction (XRD), thermogravimetric analysis (TG/DTG), wettability measurement, and swelling measurement. This study demonstrates that the external-surface physically adsorbed surfactant can be removed after washing treatment, resulting in an increase in thermal stability and a decrease in surface energy of the resultant organoclays. Organoclays are difficult to be introduced into a solvent when their surface energies are lower than that of the solvent. On the other hand, the organoclay with gamma(organoclay) < gamma(solvent) is easier to be swollen and expandable by the solvent. The swelling and basal spacing measurements of the organoclays introduced into organic media indicate that the swelling factor and the interlayer swelling are two independent parameters. Both the polar character of the solvent and the swelling capacity of clay have a prominent effect on the interlayer swelling of the organoclays.

The grafting reaction between a trifunctional silylating agent and two kinds of 2:1 type layered silicates was studied using FTIR, XRD, TGA, and 29Si CP/MAS NMR. XRD patterns clearly indicate the introduction of 3-aminopropyltriethoxysilane (gamma-APS) into the clay interlayer. In the natural montmorillonite, gamma-APS adopts a parallel-bilayer arrangement, while it adopts a parallel-monolayer arrangement in the synthetic fluorohectorite. These different silane arrangements have a prominent effect on the mechanism of the condensation reaction within the clay gallery. In natural montmorillonite, the parallel-bilayer arrangement of gamma-APS results in bidentate (T2) and tridendate (T3) molecular environments, while the parallel-monolayer arrangement leads to monodentate (T1), as indicated by 29Si CP/MAS NMR spectra. This study demonstrates that the silylation reaction and the interlayer microstructure of the grafting products strongly depend on the original clay materials.

14 cases of idiopathic rapidly progressive glomerulonephritis (I. R. P. G. N.) treated by heparin between 1968 and 1974 were collected by the authors. Extra-capillary crescents (E. C. C.) occurred in 75 to 100% of glomeruli in ten patients and in 50 to 75% in four. Gross proteinuria, hematuria and renal failure were always present. 9 patients were admitted with primary oligo-anuric renal failure. 11 patients were treated by repeated hemodialysis before and during anticoagulant treatment. Heparin was given by intra-venous injection every 3 hours for one to two months with Howell times range from 150 to 200% of control. Heparin was the only treatment in 6 cases, and was given with dipyridamole in 4, with prednisone in 3 and with azathioprine in one case. 5 severe or fatal hemorragic complications were observed. The clinical course was usually unfavorable with 5 early deaths, 3 provisional steady-states with 2 late deaths. Six patients were treated by periodic hemodialysis. Repeat kidney biopsies were obtained in 8 patients. The findings suggest that heparin affects mainly the E. C. C. and fibrinoid deposits but not glomerular sclerosis. The inefficiency of all current treatments of primary oligo-anuric IRPGN is stressed. In patients with better initial renal function choice between anticoagulant and/or immuno-depressive drugs must be scrutinized in individual cases bearing in mind potential iatrogenic complications. In equivocal cases, patients should be referred to the chronic hemodialysis and/or transplantation program.