Hydrated melts

From a hydrate melting standpoint it is possible in the winter time to have too cold a liquid temperature and thus plug the liquid outlet of the low temperature separator. It is easier for field personnel to understand and operate a line heater for hydrate control and a multistage flash or condensate stabilizer system to maximize liquids recovery. 

A mixture of 3.4 parts of 7-chloro-4-fluorobutyrophenone, 4 parts of 1-(4-piperidyl)-2-benzimidazolinone hydrochloride, 6 parts of sodium carbonate and 0.1 part of potassium iodide in 176 parts of 4-methyl-2-pentanone is stirred and refluxed for 48 hours. The reaction mixture is cooled and 120 parts of water is added. The separated organic layer is dried over magnesium sulfate and the solvent is evaporated to leave an oily residue which is dissolved in dilute hydrochloric acid and boiled. The acidic solution is filtered and cooled at room temperature whereupon there crystallizes from solution l-<1-[ y-(4-fluorobenzoyl)-propyl]-4-piperidvl>-2-benzimidazolinone hydrochloride hydrate melting at about 134°-142°C. 

Willmore CC, Boudreau AE, Spivack AJ, Kruger FJ (2002) Halogens of the Bushveld complex. South Africa S Cl and Cl/F evidence for hydration melting at the source region in a back-arc setting. Chem Geol 182 503-511... 

Sultan, N. Cochonat, P. Foucher, J.-P. Mienert, J. (2004a). Effect of gas hydrates melting on seafloor slope instability. Marine Geology, 213 (1-4), 379-401. 

Calcium(II) chloride hexahydrate melts, supercooling phenomenon, 39 430, 432 Calcium(II) chloride hydrate, melt, 39 426-432... 

The isomers of dinitroglycerine have been separated by Will, Haanen and Stohrer [7], utilizing the capacity of the a-isomer to form a crystalline hydrate. Thus by cooling dinitroglycerine with a 3.2% water content, crystallization of the hydrate occurs, whilst the /3-isomer hydrate remains in solution. The a-isomer hydrate, melting at 26°C, has the formula [CjI OHXONO Jj.I O. It dissolves readily in water and benzene. At a temperature of 40°C both hydrates lose their combined water. 

In the present frame of reference, a concentration-dependent anomaly near 1.3m, would suggest one ion per 20 water molecules, or one guest molecule per pentagonal dodecahedron of host lattice (were such the only probable structures). Solutions of the order of l-2m are rather concentrated, and one must question whether or not they should be described as concentrated solutions of solute in water or solutions of water in a crystalline hydrate melts. 

Thus, in the melting process, the solid hydrate melts by decomposing to solid H2O and a liquid solution. This liquid has the composition given by point p, known as the peritectic point. It is an invariant point, since three phases... 

Cyclen phosphine oxide is extremely hygroscopic. The hydrate melts ca. 180° with partial decomposition. 

B. Why Is the Hydrate Melt of CaCl2 RH20 with R = 6 Easily Supercooled but Hydrate Melts with R = 4 and 8.6 Are Not ... 

X-ray diffraction analysis of the structure of the hydrate melts reveals that the calcium(II) ion in the CaCl2-8.6H20 (25°C) is surrounded by six water molecules with a Ca-OH2 distance of 245 pm (see Fig. 10). Chloride ions tend to enter the first coordination sphere of the calcium(II) with decreasing water concentration in the melt to form ion... 

Fig. 9. The phase diagram of the CaCl2H20 system and composition of hydrate melts examined. (A) CaCl24H20 at 120°C (B) CaCl2-6H20 at 33°C (C) CaCl2-8.6H20 at 25°C.

Thus, the supercooling phenomenon in the calcium(II) chloride hexa-hydrate melts may be explained in terms of the dissimilarity in the structure around the calcium(II) ions in the melt and in the crystal, and the substitution of water by chloride in the coordination sphere of the calcium(II) ion in the melt should be completed during cooling. On the other hand, the CaCl24H20 hydrate melt has a very similar... 

Fig. 10. The coordination structures around calcium ions in the hydrate melts and crystals. , Ca2" O, H20 Q. Cr.

The same hydrate is obtained on allowing a concentrated solution of ferric chloride to evaporate slowly in the cold. It separates out as reniform masses of lemon-yellow crystals, or in opaque, yellow rhombic prisms, according to circumstances.4 This hydrate melts at 37°.XL — -------... 

The fact that many crystalline hydrates melt, such as Ca(W03)2-4H20, while more complex binary hydrated systems have a tendency to form glasses is an indication of the critical role of the water molecule and the hydrogen bond. 

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