Eutectic solutions

Commercial appHcations of calcium chloride and its hydrates exploit one or more of its properties with regard to aqueous solubiUty, hygroscopic nature, the heat gained or lost when one hydrated phase changes to another, and the depressed freezing point of the eutectic solution at a composition of about 30% by weight calcium chloride. 

A similar product is available for domestic use. Plastic containers hold a eutectic solution, and these are frozen down by placing these elements in the domestic deep-freeze cabinet. Once frozen, they can be used in picnic baskets, etc., for the short-term storage of cold foods, wines, ice cream, etc. 

An ongoing debate continues among researchers regarding the mechanism of the electrochemical reduction of tantalum in fluoride melts. No unified model exists for the process. Espinola et al. [545] concluded, based on an investigation of the electrochemical reduction of tantalum from a molten LiF-NaF-KF eutectic solution, that the process takes place in two stages. The first, reversible step involves the transfer of two electrons ... 

Photochemical reactions of HCN tetramers in such eutectic solutions to give 4-amino-3-cyanoimidazole (Orgel, 2004)... 

A further possibility is that tetramer formation may have occurred in an eutectic solution. High yield of tetramer (> 10%) can be obtained by cooling dilute cyanide solutions to between - 10°C and -30°C for a few months. 

Wamock RE. 1972. Escape of elemental phosphorus from soil when applied as white phosphorus or the phosphorus-sulfur eutectic solution. Journal of Environmental Quality 1 311-314. 

When solid NaOH 2H20 is heated to 10°C, it converts to a mixture of NaOH H20 and solution of composition a. During melting, this solution exists at equilibrium with the two solid phases, p = 3, and the system is invariant (at the pressure of the diagram). This is similar to the behavior of a eutectic solution, but because the solution of composition a is of lower concentration than both of the solids, it is known as a peritectic solution, with a corresponding peritectic temperature and peritectic composition. 

A different compatibility problem arises when ADN is mixed with KNO3. Aging studies show a drastic decrease in melting point. The reason is probably formation of eutectic solutions between the salts. This has also been observed in aging studies of GDN and KNO3 but not when GDN is replaced by guanylurea dinitramide (GUDN). 

The best intercomparison of t2, t4, and tq values between different solution and vapor spectra can be made in the case of Er " since data for a larger number of transitions have been obtained for it than for the other lanthanide ions. The values for Er " in DCIO4 and LiNOs-KNO.s eutectic solutions (data of CFW) and for Er(thd)3, ErBrs, and Erl vapors (present work) are listed in Table X. It can be seen that t4 and tq are roughly constant in all of these systems while t2 increases by a factor of 66 in going from an aqueous solution to the triiodide vapor. 

EUTECTIC POINT - Freezing temperature for eutectic solutions. 

The L-form composition in eutectic solution is constant at 70% at atmospheric pressure as seen in Figure 5. It shifts to the racemic side when the pressure is elevated (conq>are Figure 4 and Figure 5). It is clear that the region of chiral formation Incomes wider at elevated pressure. In these experimental conditions, the zone of racemic con und formation didn t disi pear but only diminished. The mandelic acid in mother liquor separated from the feed C (L-70%) was 62 to 64% in its L-form concentration and the concentration were higher than the solubility of both the chiral and the racemic of mandelic acid. The analytical results showed that the obtained crystals contained both L-form and D-form Furthermore, XRD analysis of these crystals revealed that L-form and D-form in these crystals are derived from L-form crystals and from the racemic crystals respectively. 

In the temperature range from -20°C to -80°C glycerin controls the crystallization process and makes it reversible, thus eliminating eutectic solutions caused by the presence of salt solutions. It also shifts the coordinates of eutectic borders and contributes to the formation of vitreous structures. 

The photocatalyzed Meerwein arylation Classic reaction of aryl diazonium salts, in particular, direct C—H arylation ofheteroarenes 13AG(E)4734. Prebiotic chemistry in eutectic solutions at the water—ice matrix 12CSR5404. 

Phase stability regions can be identified without the need to measure a full phase diagram experimentally. Eutectic solution compositions can be measured to identify stability regions and if desired to calculate a full phase diagram by considering the solution phase equilibria and associated equations. 

The relationship between. Keu and a, for carbamazepine co-crystals in aqueous solutions with different pH values and in several organie solvents is shown in Figure 11.16. The data points represent. Keu values and solubilities obtained from measured eutectic solution concentrations of eo-crystal components according to equations (11.40) and (11.42). Co-crystal stoichiometric solubilities increase relative to drug solubility as the [eo-former]eu increases relative to the [drugjeu- Other eo-crystal stoichiometries and solution equilibria are presented in the original publication. ... 

Liquid layer develops on the surface of fluidiaed particles in spray coating/granulatioa or in olefin potymeiization- in high temperature operations, liquid phase is formed as a melt due to overheating. In fluidised bed incineration, combustion or gasification, liquid phase is formed from the ash as a eutectic solution separated from the remaining solid phase. 

Figure 3.16 presents the corrosion rates for GW103K in the different heat treatment conditions, measured by immersion in 5% NaCl solution for 3 days. The as-cast (F) condition had the highest corrosion rate due to micro-galvanic corrosion of the a-Mg matrix by the eutectic. Solution treatment led to the lowest corrosion rate, attributed to the absence of any second phase and a relatively compact protective surface film. Ageing at 250 °C increased the... 

---