Naphthalene surfaces

A full analysis of the assembly process resulted in a growth model, in which a dimer acts as a nucleation point for further growth in two dimensions as a result of the strong, hydrophobic interactions between the large naphthalene surfaces forming a so-called dimeric... 

Adsorption of a series of non-ionic surfactants on to sulphathiazole and naphthalene has been compared [31]. The lower adsorption on to the naphthalene surface is reflected in the high areas/molecule given in Table 9.2. The packing of the surfactants on sulphathiazole is closer than at the air-water interface, perhaps suggesting that the values at the solid surface are apparent... 

Finally, it has been possible to obtain LEED patterns from films of molecular solids deposited on a metal-backing. Examples include ice and naphthalene [80] and various phthalocyanines [81]. (The metal backing helps to prevent surface charging.)... 

Water at 20°C rests on solid naphthalene with a contact angle of 90°, while a water-ethanol solution of surface tension 3S dyn/cm shows an angle of 30°. Calculate (a) the work of adhesion of water to naphthalene, (b) the criticd surface tension of naphthalene, and (c) y for naphthalene. 

Benzophenone. To o 5g.of benzophenone add 1 g. of naphthalene (as a solvent) and heat until completely molten. Add a small piece of sodium and heat again. The surface of the sodium becomes green, and the colour [which is that of the free radical, (C H5),C-ONa] spreads throughout the molten mass on strong heating. 

Liquid/Solid Mass Transfer The dissolved gas and the solvent react in contact with the surface of the catalyst. For studying the rate of transfer to the surface, an often-used system was benzoic acid or naphthalene in contact with water. A correlation of Dharwadkar and Sylvester (AJChE Journal, 23, 376 [1977]) that agrees well with some others is... 

Fillers are often employed to reduce the surface tack of the final product. Examples are talc and china clay. If powdered materials are added directly to a latex they compete for the emulsion stabiliser present and tend to coagulate the latex. They are therefore added as an aqueous dispersion prepared by ball milling the filler with water and a dispersing agent, for example a naphthalene formaldehyde sulphonate at a concentration of about 1% of the water content. Heat and light stabilisers which are solids must be added in the same way. 

Wetting agents. These facilitate the wetting of surfaces and aid colloidal stability without foaming. Naphthalene sulphonate/formaldehyde is the most common wetting agent. 

For conditions of forced convection, Frossling(5I) studied the evaporation of drops of nitrobenzene, aniline and water, and of spheres of naphthalene, into an air stream. The drops were mainly small and of the order of 1 mm diameter. Powell (44) measured the evaporation of water from the surfaces of wet spheres up to 150 mm diameter and from spheres of ice. 

The kj and terms were evaluated from Equation 2 and found to be roughly comparable to the values for naphthalene adsorbed on highly activated alumina (11,30). Generally, the smaller the and values, the more strongly the compound interacts with the surface (29,30). In the future, Equation 2 should be a useful means of comparing various surfaces for RTF in solid-surface phosphorescence analytical work. 

The flash point represents the minimum temperature at which an ignitable mixture exists above a liquid surface. By definition, flash points are inapplicable to gases. Some solids, e.g. naphthalene and camphor, are easily volatilized on heating so that flammable mixtures develop above the solid surface and hence flash points can be determined. (However, although these substances can be ignited, they generally need to be heated above their flash points in order for combustion to be sustained this is the fire point .)... 

The surface analyses of the Co/MgO catalyst for the steam reforming of naphthalene as a model compound of biomass tar were performed by TEM-EDS and XPS measurements. From TEM-EDS analysis, it was found that Co was supported on MgO not as particles but covering its surface in the case of 12 wt.% Co/MgO calcined at 873 K followed by reduction. XPS analysis results showed the existence of cobalt oxide on reduced catalyst, indicating that the reduction of Co/MgO by H2 was incomplete. In the steam reforming of naphthalene, film-like carbon and pyrolytic carbon were found to be deposited on the surface of catalyst by means of TPO and TEM-EDS analyses. 

Madsen EL, CL Mann, SE Bilotta (1996a) Oxygen limitations and aging as explanations for the field persistence of naphthalene in coal tar-contaminated surface sediments Environ Toxicol Chem 15 1876-1882. 

Fig. n.5 COSMO surfaces for two pairs of compounds differing by the mutation of an aromatic CH- group to an aromatic nitrogen (a) naphthalene, (b) quinoline, (c) indole and (d) benzimidazole. The influence of the aromatic nitrogen on the aqueous solubility is very dissimilar in both cases. 

The SH signal directly scales as the square of the surface concentration of the optically active compounds, as deduced from Eqs. (3), (4), and (9). Hence, the SHG technique can be used as a determination of the surface coverage. Unfortunately, it is very difficult to obtain an absolute calibration of the SH intensity and therefore to determine the absolute number for the surface density of molecules at the interface. This determination also entails the separate measurement of the hyperpolarizability tensor jS,-, another difficult task because of local fields effects as the coverage increases [53]. However, with a proper normalization of the SH intensity with the one obtained at full monolayer coverage, the adsorption isotherm can still be extracted through the square root of the SH intensity. Such a procedure has been followed at the polarized water-DCE interface, for example, see Fig. 3 in the case of 2-( -octadecylamino)-naphthalene-6-sulfonate (ONS) [54]. The surface coverage 6 takes the form ... 

Use the test-tube clamp to hold the test tube vertically in the boiling water bath. Make sure all of the naphthalene is below the surface of the boiling water. When the naphthalene has melted, insert the rubber stopper assembly into the top of the test tube. CAUTION The test tube may be hot. The thermometer should be immersed in the naphthalene. The stirring wire should loop around the thermometer. Move the stirring wire up and down to stir the contents of the test tube. Stir the naphthalene as it is being heated until all of the naphthalene has melted. 

Scraped surface Organic compounds, where fouling is a problem, viscous materials Chlorobenzenes, organic acids, paraffin waxes, naphthalene, urea... 

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