Solvents solvency measurement

Kauri-butanol number A measurement of solvent strength for hydrocarbon solvents the higher the Kauri-butanol (KB) value, the stronger the solvency the test method (ASTM D1133) is based on the principle that Kauri resin is readily soluble in butyl alcohol but not in hydrocarbon solvents and that the resin solution will tolerate only a certain amount of dilution and is reflected as cloudiness when the resin starts to come out of solution solvents such as toluene can be added in a greater amount (and thus have a higher KB value) than weaker solvents such as hexane. 

The mechanism by which emulsion scouring occurs is attributed to the hydro-phobic portion of the micelle being saturated with the solvent. The micelle, when loaded with solvent, is more effective in solubilising oily impurities from the fabric than is the detergent alone, provided both solvent and emulsifier are properly selected and used. The critical feature of such a solvent is its KB Value, which is a measure of its solvency for a particular oily soil. 

The cohesive energy density e is a specific temperature-dependent parameter for each solvent and represents a direct thermodynamic measure of the forces of attraction in solvents. It can be used to evaluate the solvency of the solvents if the cohesive energy densities of the substances to be dissolved are also known. 

The dilution ratio reveals some similarities between the solvency of different solvents. However, most measurements are restricted to cellulose nitrate, and extrapolation of the results to other binders seldom provides correct results. Furthermore the dilution ratios, unlike solubility parameters, are unable to explain several phenomena (e.g., the enhancement of the solvency of a solvent produced on adding a non-solvent). 

Solvency and cleaning ability may also be evaluated as a function of density, viscosity, and surface tension. The lower the viscosity and surface tension and higher the density, the better the wettability, hence the ability to dissolve and remove residues. Surface tension is a measure of the penetrating power of a solvent low surface tension solvents are better able to penetrate and wet tight spacings. The surface tensions of non-linear alcohols are typically low (20-22 dynes/cm) whereas that of water is high (72.8 dynes/cm). 

Kauri Butanol (KB) Value. A measure of the solvency of a hydrocarbon solvent values range from 20 (poor) to over 1000 (excellent), ketone. A class of liquid organic compounds in which the carbonyl group, is attached to two alkyl groups. The simplest member of the series is acetone others include diethyl ketone and methyl ethyl ketone. 

Also the paint industry, formerly the main end-user of solvents, attempted to produce a quantitative solvent power data system [5]. This related solvency to certain standard solutes, used in their industry. These could either be a well-known natural (Kauri-resin) or later a synthetic (nitrocellulose) paint binder. The result was the introduction of the Kauri-Butanol number, which applies to hydrocarbon solvents only and the NC-dilution ratio which is used for oxygenated solvents. Another test, used in conjunction with hydrocarbon solvents, is based on the fact that aniline is hardly miscible with aliphatic hydrocarbons but mixes very well with aromatics. The Kauri-Butanol (KB) number as defined in ASTM D 1133 is a measure of the tolerance of a standard solution of Kauri resin in -butanol to hydrocarbon diluent. Standard hydrocarbon solvents used to calibrate the Kauri solution are toluene (KB-number 105) and a 75% v -heptane/25% v toluene blend (KB-number 40). The KB-value increases from approx. 20 to over 100 in the order ... 

This volume is divided into two parts. Part 1 provides a detailed and authoritative review of the science and technology of solvents and issues relating to solvents, written by respected figures from within the solvents industry. The topics covered are solvency and its measurement, flammability, health and toxicology, environmental issues, legislative information, transport, storage, recovery and disposal, and a review of solvent applications. 

Table 7.7 lists the solvent-resin radius of interaction values, of five resins with each of twelve alcohols. These values are a measure of the solubility of the resin in the solvent. As described in Chapter 5 the total solubility parameter of a resin is the point in three-dimensional space where the three partial solubility parameter vectors meet as the center point of the idealized spherical solubility envelope. The distance in space between two sets of solvent-resin parameters can be represented by the term radius of interaction or The spreadsheet SPWORKS.WKJ, which lists some 166 resins and polymers and 289 solvents, was used to calculate the R values given in Table 7.7. Small R values (e.g., less than 10) signify good solvency for the resin while higher values suggest a poor solvent for the resin. If the actual radius of the resin solubility envelope is known then the R value should be less than the resin radius if the solvent is to dissolve the resin.

The Kauri-butanol value, used to rate solvency of hydrocarbon solvents, is defined in ASTM Method D 1133 as the volume in milliliters of the hydrocarbon solvent at 25 °C that is required to produce a defined degree of turbidity when titrated into a specified quantity of a standard clear solution of kauri resin in n-butyl alcohol. Kauri-butanol values range from approximately 20 for the weakest hydrocarbon solvents to more than 100 for stronger aromatic solvents. The test is limited to hydrocarbon solvents and is not applicable to oxygenated solvents. As Kauri resin (a natural resin) is no longer easily available, the test has not maintained its acceptance in the industry. Aniline point (or mixed aniline point), another measure of solvency of hydrocarbon solvents, is more accepted. The ani-... 

The kauri-butanol value is used as a measure of solvent power of hydrocarbon solvents. High kauri-butanol values indicate relatively strong solvency. 

A range of smface force methods have been used during the last 25 years for accmate measurements of classical DLVO forces (electrostatic doublelayer and van der Waals forces), polymer-induced forces (steric, bridging, depletion) under a range of solvency conditions, as well as short-range hy-dration/protrusion forces and long-range attractive forces between nonpolar surfaces in polar solvents. In particular, the interferometric stuface force... 

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