Surface tension, organic compounds

Steroid Hormones and Other Steroidal Synthetics Sublimation Pressure for Organic Compounds Surface Tension of Liquid Elements Temperature Correction for Barometer Readings Temperature Correction for Glass Volumetric Apparatus Temperature Correction for Volumetric Solutions Temperature Correction, Glass Scale... 

The surface tensions for solutions of organic compounds belonging to a homologous series, for example, R(CH2)nX, show certain regularities. Roughly, Traube [145] found that for each additional CH2 group, the concentration required to give a certain surface tension was reduced by a factor of 3. This rule is manifest in Fig. lll-15b the successive curves are displaced by nearly equal intervals of 0.5 on the log C scale. 

Revised material for Section 5 includes the material on surface tension, viscosity, dielectric constant, and dipole moment for organic compounds. In order to include more data at several temperatures, the material has been divided into two separate tables. Material on surface tension and viscosity constitute the first table with 715 entries included is the temperature range of the liquid phase. Material on dielectric constant and dipole... 

FLUORINECOMPOUNDS,ORGANIC - FLUORINATEDALIPHATICCOMPOUNDS] (Volll) -surface tensions of [FLUORINE COMPOUNDS, ORGANIC - INTRODUCTION] (Volll)... 

The low surface tension of highly fluorinated organic compounds is commercially important for their appHcation in surfactants, antisoiling textile treatments, lubricants, and specialty wetting agents. 

Jarvis, N.L. and Zisman, W.A. "Surface Activity of Fluorinated Organic Compounds at Organic-Liquid/Air Interfaces Part II. Surface Tension vs Concentration Curves, Adsorption Isotherms, and Force-Area Isotherms for Partially Fluorinated Carboxylic Esters," Naval Research Labs Report 5364, Surface Chemistry Branch, Chemistry Division, October 8, 1959. 

The adsorption of organic molecules offers a rich phenomenology. A large number of studies have been performed on mercury electrodes, where the surface tension can be measured directly, and the surface charge and the capacity obtained by differentiation. We will not attempt to survey the literature, but consider a simple example the adsorption of aliphatic compounds. 

At concentrations above their aqueous solubility, the so-called c.m.c., low-molar-mass biosurfactants form micelles in the aqueous phase. Micelles are spherical or lamellar aggregates with a hydrophobic core and a hydrophilic outer surface. They are capable of solubilising nonpolar chemicals in their hydrophobic interior, and can thereby mobilise separate phase (liquid, solid or sorbed) hydrophobic organic compounds. The characteristics for the efficiency of (bio)surfactants are the extent of the reduction of the surface or interfacial tension, the c.m.c. as a measure of the concentration needed to bring about this reduction, and the molar solubilisation ratio MSR, which is the number of moles of a chemical solubilised per mole of surfactant in the form of micelles [96]. 

Industrially, silicone surfactants are used in a variety of processes including foam, textile, concrete and thermoplastic production, and applications include use as foam stabilisers, defoamers, emulsifiers, dispersants, wetters, adhesives, lubricants and release agents [1]. The ability of silicone surfactants to also function in organic media creates a unique niche for their use, such as in polyurethane foam manufacture and as additives to paints and oil-based formulations, whilst the ability to lower surface tension in aqueous solutions provides useful superwetting properties. The low biological risk associated with these compounds has also led to their use in cosmetics and personal care products [2]. 

The addition of a small quantity of electrolyte (such as minerals dissolved from adjacent soil particles) increases surface tension. A small quantity of soluble organic compound (alcohol, soap, or acid) decreases the surface tension. The addition of glycerine to water reduces surface tension and thus makes it possible to stretch water him into bubbles, as with a child s bubble-blowing game. 

Werner complex See coordination compound. ver-nor, kam,picks ) wet aahing org chem The conversion of an organic compound into ash (decomposition) by treating the compound with nitric or sulfuric acid. wet ash-ii) wettability chem The ability of any solid surface to be wetted when in contact with a liquid that is, the surface tension of the liquid is reduced so that the liquid spreads over the surface.. wed-a bil-od-e ... 

Evidence of attachment of an organic molecule to a metal surface by a particular group in the molecule is not only provided from surface tension data on the surface of liquid mercury but is also to be noted in the phenomenon of displacement of one liquid by another from a surface. The hydrocarbons adhere to metals much less tenaciously than molecules containing polar groups such as —COOH and —OH. Thus we find that a hydrocarbon may be removed from a metal surface by displacement with alcohol and also that the lubricating properties of a hydrocarbon are materially affected by the addition of hydrocarbon compounds containing polar groups (Hardy, Proc. Roy. 8oc. A, c. 650, 1922, A, ci. 487, 1923). 

The monobasic acids all show a more marked E.M.P than the corresponding salts. They also lower the surface tension of water. The anions appear therefore to approach nearer to the surface in the presence of H ions than K ions. In KOH the e.m.p. is reversed, the K being less repelled from the surface than the OH. Ammonium salts behave like potassium salts except that ammonia is quite different to the other bases, giving a strong reversed E.M.P. and lowering the surface tension of. water like an organic compound. 

Kerosene is a mixture of aliphatic and aromatic hydrocarbons, naphthenes (cycloalkanes) and other organic compounds. Systemic absorption from the lungs or stomach can cause central nervous system depression. The oil has a low surface tension and low viscosity so that small quantities can spread over a large surface area. This can affect the lungs, and... 

Shulman, M., M. Jacobson, R. Charlson, R. Synovec, and T. Young, Dissolution Behavior and Surface Tension Effects of Organic Compounds in Nucleating Cloud Droplets, Geophys. Res. Lett., 23, 277-280 (1996). 

Note that we make a distinction between a solution and a mixture. When we talk of a solution, we imply that the organic solute is not a major component of the bulk liquid. Therefore, that presence of a dissolved organic compound does not have a significant impact on the properties of the bulk liquid. In contrast, in a mixture we recognize that the major components contribute substantially to the overall nature of the medium. This is reflected in macroscopic properties like air-liquid surface tensions and in molecule-scale phenomena like solubilities of trace constitutents. 

---