Volatile organic solutes

Munz C, Roberts PV. 1987. Air-water phase equilibria of volatile organic solutes. J Am Water Works Assoc 79 62-69. 

Equipment and reagents Ultrasound generator, pulse generator, photomultiplier tube, oscilloscope, light-insulated cabinet, rare gas source (e.g. argon), 3-ami-nophthalhydrazide (luminol), sodium hydroxide, alcohol or other volatile organic solutes. 

Roberts, P.V., Munz, C., and Dandliker, P. Modeling volatile organic solute removal by surface and bubble aeration, 7. Water Pollut. ControlFed., 56(2) 157-163, 1984. 

Munz, C., and P. V. Roberts, Air-Water Phase Equilibria of Volatile Organic Solutes. J. Am. Water Works Assoc., 1987 May, 62-69. 

Temperature-controlled refractometers are available for refractive index measurements of liquid samples and solutions. Such refractometers are stable and precise, and are applicable for both aqueous and volatile organic solutions such as those made with acetone or alcohol. A differential refractometer is used to obtain the exact percent solids of diluted solutions (nominal 1% polymer solutions or lower). In the case of both types of refractometers, the percent solids measurements are made relative to a calibration of the refractive indices of standard solutions of known concentration. 

Simons DS, Colby BN, Evans CA Jr. Electrohydrodynamic ionization mass spectrometry— the ionization of liquid glycerol and non-volatile organic solutes. Int J Mass Spectrom Ion... 

Hydrolysis of a substituted amide. A. With 10 per cent, sulphuric acid. Reflux 1 g. of the compound (e.g., acetanilide) with 20 ml. of 10 per cent, sulphuric acid for 1-2 hours. Distil the reaction mixture and collect 10 ml. of distillate this will contain any volatile organic acids which may be present. Cool the residue, render it alkaline with 20 per cent, sodium hydroxide solution, cool, and extract with ether. Distil off the ether and examine the ether-soluble residue for an amine. 

For aqueous inks, the resins are water- or alkali-soluble or dispersible and the solvent is mosdy water containing sufficient alcohol (as much as 25%) to help solubilize the resin. To keep the alkah-soluble resin in solution, pH must be maintained at the correct level. Advances include the development of uv inks. These are high viscosity inks that require no drying but are photocurable by uv radiation. In these formulations, the solvent is replaced by monomers and photoinitiators that can be cross-linked by exposure to uv radiation. The advantage of this system is the complete elimination of volatile organic compounds (VOC) as components of the system and better halftone print quaUty. Aqueous and uv inks are becoming more popular as environmental pressure to reduce VOC increases. 

The copolymers are insoluble in water unless they are neutralized to some extent with base. They are soluble, however, in various ratios of alcohol and water, suggesting appHcations where deUvery from hydroalcohoHc solutions (149) but subsequent insolubiUty in water is desired, such as in low volatile organic compound (VOC) hair-fixative formulations or tablet coatings. Unneutralized, their Ts are higher than expected, indicating interchain hydrogen bonding (150). 

Solution Deposition of Thin Films. Chemical methods of preparation may also be used for the fabrication of ceramic thin films (qv). MetaHo-organic precursors, notably metal alkoxides (see Alkoxides, metal) and metal carboxylates, are most frequently used for film preparation by sol-gel or metallo-organic decomposition (MOD) solution deposition processes (see Sol-GEL technology). These methods involve dissolution of the precursors in a mutual solvent control of solution characteristics such as viscosity and concentration, film deposition by spin-casting or dip-coating, and heat treatment to remove volatile organic species and induce crystaHhation of the as-deposited amorphous film into the desired stmcture. 

Steam stripping Aqueous solutions of volatile organics Concentrated aqueous streams with volatile organics and dilute stream with residuals... 

An amount of enzyme preparation equivalent to 900 mg of wet cells was made up to 25 ml with the above potassium phosphate buffer solution. 150 mg (1.15 mmol) of 5-fluorouracil and 1.0 gram of thymidine (4.12 mmol) were dissolved in 15 ml of the above potassium phosphate buffer solution. The mixture was incubated at 37°C for 18 hours. After this time, enzyme action was stopped by the addition of four volumes of acetone and one volume of peroxide-free diethyl ether. The precipitated solids were removed by filtration, and the filtrate was evaporated under nitrogen at reduced pressure until substantially all volatile organic solvent had been removed. About 20 ml of aqueous solution, essentially free of organic solvent, remained. This solution was diluted to 100 ml with distilled water. 

However, it should be mentioned that the dissolution process of a solid, crystalline complex in an (often relatively viscous) ionic liquid can sometimes be slow. This is due to restricted mass transfer and can be speeded up either by increasing the exchange surface (ultrasonic bath) or by reducing the ionic liquid s viscosity. The latter is easily achieved by addition of small amounts of a volatile organic solvent that dissolves both the catalyst complex and the ionic liquid. As soon as the solution is homogeneous, the volatile solvent is then removed in vacuo. 

Li and Hsiao [143] provide a useful approach to the environmental problem of removing (by stripping) volatile organics from solution in a contaminated water stream by using fresh air as the stripping medium. It should be noted that a number of industrial firms perform this stripping with steam. The mass balance on the VOC component around the column (trayed or packed) as shown in Figure 8-55 uses the symbols of Reference 143. 

Roberts PV, Dandliker PG. 1983. Mass transfer of volatile organic contaminants from aqueous solution to the atmosphere dirring surface aeration. Environmental Science and Technology 17 484-489. 

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