Water miscibility

C HjCla, PhCCla. Colourless liquid, b.p. 2I3-214" C. Insoluble in water, miscible with organic solvents. 

CHJOCH2CH2OCHV A water-miscible colourless liquid, b.p. 83 C, used in selected reactions as an alternative to diethylether. 

Worldwide demand for DMF in acryhc fiber production has held up better than in the United States. The high solubiUty of polyacrylonitrile in DMF, coupled with DMF s high water miscibility, makes it an attractive solvent for this appHcation. Its principal competition in this area comes from DMAC. 

Figure 4a represents interfacial polymerisation encapsulation processes in which shell formation occurs at the core material—continuous phase interface due to reactants in each phase diffusing and rapidly reacting there to produce a capsule shell (10,11). The continuous phase normally contains a dispersing agent in order to faciUtate formation of the dispersion. The dispersed core phase encapsulated can be water, or a water-immiscible solvent. The reactant(s) and coreactant(s) in such processes generally are various multihmctional acid chlorides, isocyanates, amines, and alcohols. For water-immiscible core materials, a multihmctional acid chloride, isocyanate or a combination of these reactants, is dissolved in the core and a multihmctional amine(s) or alcohol(s) is dissolved in the aqueous phase used to disperse the core material. For water or water-miscible core materials, the multihmctional amine(s) or alcohol(s) is dissolved in the core and a multihmctional acid chloride(s) or isocyanate(s) is dissolved in the continuous phase. Both cases have been used to produce capsules. 

In addition to these forms of water, several other official aqueous vehicles can be used. These are isotonic injections that can be sterilised, eg, sodium chloride. Ringer s, dextrose, dextrose and sodium chloride, and lactated Ringer s. Addition of water-miscible solvents such as ethanol or propylene glycol increases solubiUty and stabiUty. 

The phenoHc resins used for particle board are NaOH-catalyzed resoles of low viscosity and high water miscibility, similar to the Hquid resole adhesives used in plywood manufacture. The higher resin and caustic content of the board frequently necessitates the addition of hydrophobic agents such as wax emulsions to increase the barrier properties of the board. The adhesive is appHed to the particles in thin streams using high agitation to maximize material usage. Boards are cured in presses for 5—10 min at 150—185°C. 

As solvents, the amyl alcohols are intermediate between hydrocarbon and the more water-miscible lower alcohol and ketone solvents. Eor example, they are good solvents and diluents for lacquers, hydrolytic fluids, dispersing agents in textile printing inks, industrial cleaning compounds, natural oils such as linseed and castor, synthetic resins such as alkyds, phenoHcs, urea —formaldehyde maleics, and adipates, and naturally occurring gums, such as shellac, paraffin waxes, rosin, and manila. In solvent mixtures they dissolve cellulose acetate, nitrocellulose, and ceUulosic ethers. 

The butanols are all colorless, clear Hquids at room temperature and atmospheric pressure with the exception of /-butyl alcohol which is a low melting soHd (mp 25.82°C) it also has a substantially higher water miscibility than the other three alcohols. Physical constants (1) of the four butyl alcohols are given in Table 1. 

Although equihbrium-controUed peptide synthesis has been successfully used on a number of occasions, including thermolysin-catalyzed synthesis of aspartame (126) and semisynthesis of insulin (127), the method has a significant drawback a water-miscible organic cosolvent added to the reaction medium to suppress the ionization of unactivated carboxy components significantly reduces the reaction rate. 

In reversed-pViase chromatography (RPC), the mobile phase modulator is typically a water-miscible organic solvent, and the stationary phase is a hydrophobic adsorbent. In this case, the logarithm of solute retention factor is commonly found to be linearly related to the volume fraction of the organic solvent. 

Poly(vinyl chloride) is commercially available in the form of aqueous colloidal dispersions (latices). They are the uncoagulated products of emulsion polymerisation process and are used to coat or impregnate textiles and paper. The individual particles are somewhat less than 1 p,m in diameter. The latex may be coagulated by concentrated acids, polyvalent cations and by dehydration with water-miscible liquids. 

Toxic products may be produced care must be exercised after use in confined spaces. Special foam required for water-miscible liquids. 

If the column is contaminated with hydrophobic compounds, clean it with water-miscible organic solvents such as MeOH, CHjCN, or EtOH. Concentrations of 10-20% organic in water should be sufficient for cleaning. 

Properties.—Colourless liquid, with an agreeable fruity smell b. p. 77° sp. gr. o 9o68 at 15° soluble in about 11 parts of water miscible in all pioportions with alcohol, ether, and acetic acid. 

---