Water solubility rules

Commercially, HEC is available in a wide range of viscosity grades, ranging from greater than 500 mPa-s(=cP) at 1% soHds to less than 100 mPa-s(=cP) at 5% total soHds. Because HEC is nonionic, it can be dissolved in many salt solutions that do not dissolve other water-soluble polymers. It is soluble in most 10% salt solutions and in many 50% (or saturated) salt solutions such as sodium chloride and aluminum nitrate. As a rule, the lower substitution grades are more salt-tolerant. 

Hydrophobic fibers are difficult to dye with ionic (hydrophilic) dyes. The dyes prefer to remain in the dyebath where they have a lower chemical potential. Therefore nonionic, hydrophobic dyes are used for these fibers. The exceptions to the rule are polyamide and modified polyacrylonitriles and modified polyester where the presence of a limited number of ionic groups in the polymer, or at the end of polymer chains, makes these fibers capable of being dyed by water-soluble dyes. 

Here is a rule of thumb that can help us predict solubility in order to have a high water-solubility, there should be no more than 5 carbon atoms per OH group. A compound with two OH groups and 7 carbon atoms will be very soluble in water. A compound with one OH group and 7 carbon atoms will NOT be very soluble in water. There are, of course, many exceptions to this simplified rule of thumb, but the rule can be helpful whenever we need to make a quick prediction about the solubility of an alcohol. 

We have developed a new set of rules, called J-Alert , that contains cut-offs for human jejunal permeability, water solubility, the number of oxygen-based H-bond acceptors, partial charge sums on the oxygen-based H-bond donors and acceptors, and a low level cut-off for the Moriguchi log P [28]. The J-Alert rules and a two-letter abbreviation are listed as follows ... 

The solubility parameter of water is 17 or 23, depending on the association structure of water used in the calculation. None of the values listed in Table II are within two units of either value and by the general rules of the solubility concept, none of the polymers in Table II should be water soluble. Homopolymers of monomers c, e, or f in Figure 3 are not water soluble. The solubility values listed for the W-SPs studied do not correlate with the equilibrium pressures observed. A general correlation is noted if the values of the most hydrophobic segments (i.e., the oxypropyl, oxybutyl and acetate) are compared with PMVE. The... 

Ammonium chloride is soluble in water (see the solubility rules on page 116). Therefore, the concentration NH4+ and that of Cl are both 0.20 M. 

These problems involve mixing two solutions. Each solution is a water solution of an ionic compound. From the mixture of the two solutions, at least one insoluble precipitate will form. The other ions present are probably soluble and are called spectator ions they are not included in the net ionic equation. You must know your solubility rules to do these problems. 

Showing the strong electrolytes in the form of ions yields the ionic equation (sometimes called the total or overall ionic equation). The strong electrolytes are any strong acid, strong base, or water soluble (according to the solubility rules) ionic compound. In this example, the ionic equation is ... 

TABLE 2.1 Solubility Rules for Ionic Compounds in Water... 

Water. It should come as no surprise that ordinary water can be an excellent solvent for many samples. Due to its extremely polar nature, water will dissolve most substances of likewise polar or ionic nature. Obviously, then, when samples are composed solely of ionic salts or polar substances, water would be an excellent choice. An example might be the analysis of a commercial iodized table salt for sodium iodide content. A list of solubility rules for ionic compounds in water can be found in Table 2.1. 

Kolbe hydrocarbon synthesis orgchem The production of an alkane by the electrolysis of a water-soluble salt of a carboxylic acid. kol-bo. hT-dro kar-bon, sin-th3-s3s Kolbe-Schmitt synthesis org chem The reaction of carbon dioxide with sodium phenoxide at 125°C to give salicyclic acid. kol-bo shmit, sin-th3-s3s Konowaioff ruie phys chem An empirical rule which states that in the vapor over a liquid mixture there is a higher proportion of that component which, when added to the liquid, raises its vapor pressure, than of other components., k6-n9 va-lof, rul ... 

The previous experimental observations reported in the preceding text are, at least to a certain extent, in agreement with the well-known Bancroft rule. Indeed, a double W/O/W emulsion turns into a simple direct one when a sufficient quantity of the water-soluble surfactant is added. Similarly, by shaking a 1 1 mixture of water and oil, each phase containing one of the two types of surfactants, a direct emulsion is obtained if the aqueous phase contains a large amount of water-soluble... 

Systematic rules for the influence of substituents can be derived as demonstrated for phenols in Figure 2.11. The introduction of chloro and methyl groups reduces water solubility and increases... 

Ca, CaO, Ca(OH)2, and CaCOa can be dissolved in acids to produce the corresponding Ca+ salts. Most Ca" " salts are white, except those with colored anions, and their solubilities follow the solubility rules of Chapter 4 quite well. These rules incorporate the insoluble Cap2 and CaS04 as exceptions to the major generalizations. In solution the Ca" " cation is hydrated with 6 to 9 water molecules depending upon the counter anion and the concentration. 

As a general rule, the addition of ethylene oxide to a resin backbone will tend to increase the water solubility of the compound. The addition of propylene oxide or butylene oxide to the resin will tend to increase the hydrocarbon solubility of the compound. Often, the dehazer or demulsifier can be made to perform selectively in oil-water systems by adding both ethylene oxide and propylene oxide to the same molecule. Performance and solubility of the alkoxylated compound can then be finely tuned by closely controlling the amount and order of epoxide addition. A random EO-PO based fuel demulsifier is shown in FIGURE 6-6. 

The rules governing the water solubility of polymers are similar to those governing the water solubility of smaller organic molecules except that the extent of polymer solubility and the range of polymeric structures are more limited. Selected commercially available water-soluble polymers are shown in Figure 16.1. 

General solubility rules for water as a solvent must be stated in two parts, one emphasizing the negative ions of the salts, and the other emphasizing the positive ions, as follows. 

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