Water-soluble properties

All surfactants have a common molecular similarity. A portion of the molecule has a long nonpolar chain, frequently a hydrocarbon chain, that promotes oil solubility but water insolubility (the hydrophobic portion— water hating). Another part of the molecule promotes oil insoluble and water soluble properties (the hydrophilic portion—water loving). 

The hydrophilic component of the molecule consists of a tertiary amine in all cases except for prilocaine which contains a secondary amine group (Figure 5.4). This confers water-soluble properties on the molecule. 

Malcolm et al. (14) and Thurman et al. (15) noticed that the adsorption of solutes onto XAD-8 macroreticular resin could be predicted by means of a linear correlation between the logarithm of the capacity factor and the inverse of the logarithm of the water solubility of each compound. Their investigation, however, was limited to approximately 20 selected organic compounds in individual aqueous solutions. By comparing the results shown in Table II and the water solubility properties of each model compound used in this study (see Table I), it appears that the predictive model could serve for a first estimate of the recovery of multisolute solutions at trace levels. However, low recoveries and the erratic behavior of several compounds included in this study suggest that additional factors need to be considered. 

Cornea The cornea is an important mechanical barrier protecting the intraocular tissues. It is considered to be the main pathway for ocular penetration of topically apphed drugs. However, due to its unique structure, with the hydrophilic stroma sandwiched between the highly lipophilic epithelium and the less lipophilic endothelium, the penetration of compounds through the cornea depends on their n-octanol-water partition coefficient. Only drugs with a partition coefficient between 10 and 100 that show both lipid- and water-soluble properties can readily pass through the cornea. 

We have measured the absorption of radiolabeled DDT and p u athion through excised human abdominal skin using an in vitro diffusion cell procedure. The poor water solubility properties of these compounds (Table II) suggested that a nonionic surfactant (oleth 20) would be necessary in the receptor fluid. The compounds were applied to skin in an acetone vehicle at a concentration of 4 ug/cm. The surface of the skin was cleansed with acetone at 24 h to remove unabsorbed material. The absorption of the pesticides was followed for a total of 7 days until the amount of compound entering the receptor fluid was minimal (Figures 3 and 4). 

The toted absorption of both compounds was greater in experiments with the oleth 20 receptor fluid (Table III) and so these values were used as the absorption measurements. The permeation of the least water-soluble compound, DDT, was increased to the greatest extent (4-fold) with the use of the nonionic surfactant. The absorption of parathion exceeded that of DDT, as might have been predicted from the physical chemlced properties of the molecules. The compounds are of similar molecul u weight, but parathion has much greater oil M(Jd water solubility properties. 

Sashiwa, H. and Shigemasa, Y. 1999. Chemical modification of chitin and chitosan. 2 Preparation and water soluble property of N-acylated or N-alkylated partially deacetylated chitins. Carbohydr. Polym. 39 127-138. 

Chitosan derivatives were developed to improve not only biological activities but also water-soluble property, because the water-insoluble property was a major limiting factor for industrial application in spite of its unique biological aspects. The improvement of structural properties of chitosan for a... 

Another pyrophosphate, tetrapotassium pyrophosphate (K4P2O7), also known as tetrapotassium diphosphate, is used as a builder in liquid detergent formulations at levels in the range 20-25% despite its higher cost [2]. These levels are due to its significantly higher water solubility properties when compared to the sodium salt as well as the stability of the pyrophosphate anion. Tetrapotassium pyrophosphate functions as a dispersant and binds multivalent cations, keeping them in solution. 

HISTORY. Carnitine was first isolated from meat extract in 1905, but its structure was not established until 1927. Then, another 20 years elapsed before Fraenkel, in 1947, while investigating the role of folic acid in the nutrition of insects, found that the meal worm (Tenebrio moli-tor) required a growth factor present in yeast. Frankel called this factor Vitamin BT vitamin B because of its water-soluble property, and the T standing for Tenebrio. Because of not being recognized as a vitamin, the name was subsequently changed to carnitine. 

The latter system is soluble in water and acts as an acetyl acceptor. Water-soluble properties are also reported for the tetramer 40 obtained by homocoupling of a 1,4-cis-ethynyl substituted glucopyranose [45] (Chart 7.2). The tetramer 40 contains five water molecules in the crystal [45]. 

Uses Detergent in liq. dishwashing agent defoamer Features Inverse water solubility Properties Liq. 100% cone. 

The effect of clay concentration on the oxygen permeability of a modified poly(vinyl-alcohol) was studied by many authors,it was found that sodium montmorillonite led to an improvement in the prevention of the water-soluble property. 

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