Hydrophile-lipophile balance calculation

Sorbitan ring (Sg). Phenolic ring (q>). Critical micelle concentration, obtained from the supplier and Rosen 6). Hydrophile-lipophile balance, calculated as HLB=%wt EO/5 (6). Aggregation number (5). Theoretical oxygen demand, calculated using method of Metcalf and Eddy, Inc. (17). 

One of the most important characteristics of the emulsifier is its CMC, which is defined as the critical concentration value below which no micelle formation occurs. The critical micelle concentration of an emulsifier is determined by the structure and the number of hydrophilic and hydrophobic groups included in the emulsifier molecule. The hydrophile-lipophile balance (HLB) number is a good criterion for the selection of proper emulsifier. The HLB scale was developed by W. C. Griffin [46,47]. Based on his approach, the HLB number of an emulsifier can be calculated by dividing... 

Different surfactants are usually characterised by the solubility behaviour of their hydrophilic and hydrophobic molecule fraction in polar solvents, expressed by the HLB-value (hydrophilic-lipophilic-balance) of the surfactant. The HLB-value of a specific surfactant is often listed by the producer or can be easily calculated from listed increments [67]. If the water in a microemulsion contains electrolytes, the solubility of the surfactant in the water changes. It can be increased or decreased, depending on the kind of electrolyte [68,69]. The effect of electrolytes is explained by the HSAB principle (hard-soft-acid-base). For example, salts of hard acids and hard bases reduce the solubility of the surfactant in water. The solubility is increased by salts of soft acids and hard bases or by salts of hard acids and soft bases. Correspondingly, the solubility of the surfactant in water is increased by sodium alkyl sulfonates and decreased by sodium chloride or sodium sulfate. In the meantime, the physical interactions of the surfactant molecules and other components in microemulsions is well understood and the HSAB-principle was verified. The salts in water mainly influence the curvature of the surfactant film in a microemulsion. The curvature of the surfactant film can be expressed, analogous to the HLB-value, by the packing parameter Sp. The packing parameter is the ratio between the hydrophilic and lipophilic surfactant molecule part [70] ... 

The amphiphilic nature of many emulsifying agents (particularly non-ionic surfactants) can be expressed in terms of an empirical scale of so-called HLB (hydrophile-lipophile balance) numbers222 (see Table 10.1). The least hydrophilic surfactants are assigned the lowest HLB values. Several formulae have been established for calculating HLB numbers from composition data and they can also be determined experimentally - e.g. from cloud-point measurements123,125. For mixed emulsifiers, approximate algebraic additivity holds. 

In spite of many advances in the theory of stability of lyophobic colloids, resort has still to be made to an empirical approach to the choice of emulsifier, devised in 1949 by Griffin. In this system we calculate the hydrophile-lipophile balance (HLB) of surfactants, which is a measure of the relative contributions of the hydrophilic and lipophilic regions of the... 

In Table 3.1, the hydrophilic/lipophilic balance (HLB) is calculated according to the empirical equation HLB = 20Mh/M, where Mh is the molar mass of the... 

A frequently used method is known as the HLB (hydrophile-lipophile balance) method. In this method (Griffin, 1949), a number (0-40) indicative of emulsification behavior and related to the balance between the hydrophilic and lipophilic (hydrophobic) portions of the molecule has been assigned to many commercial emulsifying agents. (In some cases, the HLB number is calculated from the structure of the molecule in other cases, it is based on experimental emulsification... 

The number of different emulsifiers is in the thousands. Even restricting selection to nonylphenol ethoxylates leaves many choices. Some parameter is necessary to compare emulsifiers. Hydrophilic/Lipophilic balance (HLB number) was developed by W.C. Griffin (Griffin, 1949, 1954) in the 40 s and describes emulsifying properties of a surfactant. Values vary between 0 and 20. A low HLB, such as 4, indicates an oil soluble emulsifier useful for dissolving small amounts of water into oil. A large number, such as 16, indicates a water soluble emulsifier useful for dissolving small amounts of oil into water. The HLB number can be determined experimentally or calculated for alkyl and aryl ethoxylates from Equation 1. 

Research into optimal formulations is based on the idea of cohesive energy ratio (CER). This was originally developed to stabilise classic non-ionic surfactant emulsions [6.13]. Despite its limitations, the CER concept unifies the ideas of solubility parameters and HUB. Recall that the HLB is a measure of the emulsifying power of surfactants and is based on their hydrophile-lipophile balance [6.3]. It can be calculated from a simple formula involving only relative weights of sequences HLB = 20 x Mh/Mt, where Mh is the molecular weight... 

The hydrophilic-lipophilic balance (HLB) value refers to the hydrophilic and lipophilic balance of a certain molecule (14). The HLB can be calculated by the Griffin method (15). There are stiU other methods to calculate the HLB value. 

Similarly, the Hydrophile-Lipophile Balance (HLB) value of a solvent can be related to the solvent s polarity and hydrogen bond character as shown by the radius of interaction JR calculations of solvent and reference hydrocarbon dodecane. 

The Hydrophile-Lipophile Balance (HLB) value of a solvent can be related to the solvent s polarity and hydrogen bond character as shown by the radius of interaction / calculations of solvent and reference hydrocarbon dodecane. The HLB values of a number of solvents were determined by the Davies method [16] and plotted against the solvent s calculated R solvent/ dodecane values. The resultant linear equation from this plot (i.e., HLB = 14.306 - 3.489 log / ), was used to estimate the solvent HLB values shown in Figure 4.5 [12]. 

A tenside with a relatively strong lipophilic group and weak hydrophilic group is mainly soluble in oil and preferentially stabilizes a w/o emulsion, and vice versa. This fact led to the development of a standard with which the relative strength or activity of the hydrophilic and lipophilic groups of emulsifiers can be evaluated. It is called the HLB value (hydrophilic-lipophilic balance). It can be determined, e. g., from dielectric constants or from the chromatographic behavior of the surface-active substance. The HLB value of the fatty acid esters of polyhydroxy alcohols can also be calculated as follows (SV =... 

In this system one calculates the hydrophile-lipophile balance (HLB) of surfactants and matches the HLB of the surfactant mixture, in the case of O/W systems, to that of the oil being emulsified. The HLB number of a surfactant is calculated according to certain empirical formulae and for non-ionic surfactants the values range from 0 to 20 on an arbitrary scale (see Fig. 8.2). At the higher... 

The concept of hydrophile-lipophile balance (HLB) was first developed by Griffin [13] to correlate the structure of surfactant molecules with their surface activity. The HLB number (0-20) reflects the hydrophilicity of surfactant, and it increases with increasing hydrophilicity. A general trendi often observed in a family of surfactants is the increased CMC with HLB. Table 2.1 serves as a general guide for the formulator to choose surfactants that are most suited to meet the requirements of end-users. This semiempirical approach has been proved to be quite useful. Davies and Rideal [14] proposed that the HLB value of a particular surfactant could be calculated according to the group contribution approach. 

The hydrophile-lipophile balance (HLB) of a surfactant typically ranges from 1 to 20 and is an indication of the relative affinity of a surfactant molecule for the oil or aqueous phase. A widely used semi-empirical method of calculating the HLB value is ... 

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