Solvent content reduction

The filtered dough is then returned to a mixer and the alcohol content reduced to 25% by kneading under vacuum. Further reduction in the alcohol content is brought about by rolling the compound on a hooded two-roll mill. The milled product is then consolidated on a two-bowl calender and sheeted off in hides about j in thick. At this stage the solvent content is between 12 and 16%. 

Polyurethanes are frequently used in anticorrosion coatings. The R D drive of most coatings and resin producers is the reduction of the solvent content of the paint and resin systems. One method of achieving the environmental aims demanded by legislation in the PU coatings industry is to use oxazolidines which are suitable as latent hardeners to enable production of single-pack moisture activated PUs. The isocyanate chosen for this research is tetramethylxylene diisocyanate, which has been available commercially only since 1988. 19 refs. 

The hydroperoxides obtained on thermal oxidation of cholesteryl acetate (191e) can be selectively separated by SPE and elution with a polar solvent. After reduction to the corresponding alcohols by NaBH4 and further derivatization to the trimethylsilyl ether, the products can be subjected to GLC with ion-trap MS detection. It can be thus demonstrated with the aid of standards that under the oxidation conditions (160 °C for 90 min) only the 7-position is attacked, leading to the la- and 7/3-hydroperoxy derivatives, while the plausible 4-position remains unscathed . Treatment of erythrocite ghosts with t-BuOOH causes a manyfold content increase of 5-hydroxyeicosatetraenoic acid (5-HETE), 5-hydroperoxyeicosatetraenoic acid (5-HPETE) and 5-oxoeicosatetraenoic acid (5-oxo-ETE) residues of phospholipids. These acids can be separated by HPLC, identified and quantitized by tandem MS . ... 

Emission and Economic Advantages. The use of Hycar 2100R series polymers offers a significant reduction in solvent emission over conventional 40% solids system (by wt.). An 83% reduction in solvent emission (figure 1) results when the 80% solids Hycar system is used. Further reduction is obtained for 90% and 100% solids systems. The solvent content of the 90% solids system is so low that neither incinerator nor heat exchanger may be needed - a very good possibility for smaller PSA converters. 

Many lithium salts, such as lithium perchlorate and the halides, are soluble in nonaqueous solvents. The reduction potential of Li depends on the electrode and the solvent. At a mercury cathode amalgam formation takes place, whereas formation of lithium metal occurs at platinum in aprotic media. Lithium metal is less reactive than sodium, and in some solvents sodium attacks the solvent whereas lithium is unreactive. A small water content in an aprotic solvent may react with lithium (or Li may react with hydroxyl ions formed at the cathode) to form lithium hydroxide, which may cover the electrode with an insoluble, insulating layer. 

The effect of heat treatment on the dissolution rate of spin coated P(MMA) film on silicon has been studied by Greeneich (7 8). The results he obtained showed very strong dependence of the dissolution rate of P(MMA) on the prebake (hot plate) temperature and time as shown in (figure 1). This result has been interpreted (7 8) as mostly due to a reduction in the solvent content (drying) during heat treatment. More recent study on the effect of prebaking on the dissolution rate of a photo resist (a Novalac resin sensitized with 20 weight % diazo compound) showed a non monotonic decrease in the dissolution rate (S)... 

Due to environmental regulations, a considerable amount of effort is being devoted to the reduction or elimination of the solvent content through the development of high-solids or 100% solids coatings, as well as water-based coatings, for example, urethane latices. Another solventless approach to this problem is urethane powder coating systems. 

Because their solvent content is as high as 75%. varnishes containing cobalt/hy-droperoxide have a pot life of several hours. The reduction in the solids content is achieved primarily through the addition of highly viscous nitrocellulose. The storage stability must be tested if styrene resins are used. 

Drastic and in some cases legally imposed reduction of solvent contents (see also Section 3.1.3)... 

It is impossible to obtain an oleate coacervate at room temperature with sodium salts floccules will be produced. The temperature exerts a great influence on the production of coacervates and in fact rise in temperature gives a reduction of the coacervate volume. In other words less KCl is necessary at high temperatures to obtain coacervation (Fig. 28). The oleate coacervates thus possess a negative temperature coefficient with respect to their solvent content. Also the influence of the organic non-electrolytes decreases relatively with rise in temperature. 

In this way, the vapor leaving the vapor degreaser is contacted with the coldest coolant, thereby effecting the greatest possible reduction of solvent content in the emitted air at that upper location. This is shown in Figures 1.32 to 1.35. 

It was determined that 30 mg/ml of DHB in acetoni-trile water (50 50, v v, with 0.1% TEA) can form evenly distributed small (0.5-20 gm mean diameter) matrix crystals on the sample surfiice. Several different combinations of matrix solution flow rate, nebulizing gas pressure, and OCN-sample distance were evaluated for matrix deposition and have been reported (12). Briefly, the matrix molecules formed irregular clusters without obvious crystal boundaries when using a high flow rate with a low gas pressure and short sprayer-sample distance. This was anticipated because these conditions would likely produce big droplets with a high solvent content (9). A reduction of the matrix solution flow rate and an increase of gas pressure and sprayer-sample distance resulted in the matrix crystals... 

In some cases, a third stripper is operated in series of the two upstream stripper vessels, for further reduction of the residual solvent contents. 

Anderson s group (Pino et al., 2009) studied the micellar properties of aqueous solutions of two ILs, l-hexadecyl-3-butylimidazolium bromide and 1,3-didodecylimidazolium bromide, in the presence of several organic solvents (methanol, 1-propanol, 1-butanol, l-p>entanol, and acetonitrile) by surface tensiometiy. For both ILs, increases in the cmc values and minimum surface area per surfactant molecule, decreases in the maximum surface excess concentration, adsorption efficiency and effectiveness of surface tension reduction were obtained when increasing the organic solvent content. 

Ce(IV) extracts more readily iato organic solvents than do the trivalent Ln(III) ions providing a route to 99% and higher purity cerium compounds. Any Ce(III) content of mixed lanthanide aqueous systems can be oxidi2ed to Ce(IV) and the resultiag solutioa, eg, of nitrates, contacted with an organic extractant such as tributyl phosphate dissolved in kerosene. The Ce(IV) preferentially transfers into the organic phase. In a separate step the cerium can be recovered by reduction to Ce(III) followed by extraction back into the aqueous phase. Cerium is then precipitated and calcined to produce the oxide. 

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