Solution-evaporation method

We have reported a study where mixtures of 6 and four imidazoles, 7-10, were prepared by two methods solution in ethanol followed by evaporation under vacuum and grinding in an agate mortar. Only in the case of 10 were differences observed by the solution/evaporation method an oil was obtained, which was explained by 10 existing as a mixture of tautomers in solution (in the solid state only 10b was present).The most interesting complex was 6 9, which has NMR properties different from a physical mixture (04CEJC660) [cited in 06PNMRS(49)169]. 

Now distil the filtrate A) and collect the distillate as long as it is acid to litmus. Should any solid separate out in the distilhng flask during the distUlation, add more water to dissolve it. Set aside the residue B) in the flask. Identify the volatile acid in the distihate. A simple method is to just neutralise it with sodium hydroxide solution, evaporate to dryness and convert the residual sodium salt into the S-benzyl-iao-thiuTonium salt (Section 111,85,5). 

The number average diameter of microspheres obtained from polymers synthesized, by emulsification of polymer solutions followed by solvent extraction and/or solvent evaporation methods, can be controlled by choosing the appropriate conditions at which particles are produced. However, by this method particles with 15 p,m and with D D > 1.9 are produced. Spray drying did not provide poly(L-Lc) particles with regular spherical shape. Direct synthesis of poly(L-Lc) microspheres by ring-opening polymerization with stepwise monomer addition can be used as a method of choice for the production of microspheres with diameters controlled to ca. 6 p.m and with diameter polydispersity parameter < 1.20. 

Table III shows that the experimental and predicted evaporation rates are in good agreement at all beam intensities. There is some inconsistency at the highest power levels. It was difficult to maintain the droplet in the center of the laser beam at the highest power level, and the measured evaporation rate is somewhat low as a result of that problem. Additional computations demonstrate that the predicted evaporation rate is quite sensitive to the choice of the imaginary component of N, so the results suggest that this evaporation method is suitable for the determination of the complex refractive index of weakly absorbing liquids. For strong absorbers, the linearizations of the Clausius-Clapeyron equation and of the radiation energy loss term in the interfacial boundary condition may not be valid. In this event, a numerical solution of the governing equations is required. The structure of the source function, however, makes this a rather tedious task.

The three main industrial methods used to produce salt are the solar evaporation method, mining of rock salt, and solution mining. The solar evaporation method is the oldest process used to obtain salt. This method is applied in geographic areas with high solar input and low... 

The incorporation of a cationic azobenzene derivative, p-( a> -dimethyl-ethanolammonioethoxyj-azobenzene bromide, into nanoporous silica films and the photochemical reactions of the adsorbed dye were investigated. The nanoporous silica films were prepared from tetramethoxysilane and octadecyltrimethyl-ammonium chloride by the rapid solvent evaporation method which we have reported previously. The adsorption of the cationic azo dye was conducted by casting an ethanol solution of the dye onto the nanoporous silica films. Upon UV light irradiation, trans-azobenzene isomerized photochemically to the c/s-form and photochemically formed c/ s-form turned back to the frans-form upon visible light irradiation. The nanoporous silica films were proved to be an excellent reaction media to immobilize organic photocromic species. 

The solution coating technique in most cases is preferred to the evaporative method because there is more uniform deposition of the phase and because there is less chance for damage of support particles. The evaporative procedure is more convenient for preparing high concentration packings (15-20%) of the viscous phases such as Carbowax, and for preparing packings with two or more stationary phases which are not soluble in a common solvent. 

A variation of this process may prove to be valuable in preparing feed for evaporators. A major difficulty in all distillation and evaporation methods is the deposit caused by magnesium ions. The amphoteric resin preferentially removes these ions. However, a very concentrated solution of sodium ions will displace magnesium ions. It would seem possible to contact the resin with sea water to remove magnesium, evapo-... 

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