Water n-hexane

Bulk vitamin Do may contain some of synthetic by-products shown in Scheme IV. Tartivita et al. (33) have reported an excellent chromatographic system which showed resolution of most of the photochemical isomers and reaction by-products. The chromatograms obtained on a 30-cm x 4-mm i.d. commercial microparticulate silica column using a 70 30 1 mixture of chloroform (free from ethanol and water), n-hexane, and tetrahydrofuran at a flow rate of 1 ml/min is shown in Figure 10. The detection was by a 254 nm UV detector. Using this system, vitamin D3 was quantitated in a resin sample containing 20 x 106 IU/g with a relative standard deviation of 1.37%. This procedure is essentially the basis for the USP XX (30) procedure for the analysis of bulk vitamin D3 which is reproduced below, in its entirety. 

Properties Fine, white, free-flowing crystals. Mp 239-240C, d 1.73. Readily soluble in acetone, benzene, toluene slightly soluble in water, n-hexane, and carbon tetrachloride. Nonflammable. 

Adsorption of water, n-hexane and benzene in mordenite and Ti-mordenite (at 298 K, p/po =... 

The sorption values of n-DBA-VPI-5 sample for water, n-hexane and 1,3,5-triisopropylbenzene (kinetic diameters = 2.65, 4.30 and 8.50 A, respectively) at 298K (p/po = 0.5 for water and n-hexane and 0.8 for triisopropylbenzene) were obtained as 33.2%, 18.5% and 11.4%, respectively. The different adsorption capacities for the above molecules is probably related to the differences in packing of these molecules. In fact, in terms of volume, water and n-hexane sorption correspond to 33 ml and 28 ml per 100 g, respectively which are more than the micropore volume of 0.124 ml/g obtained from nitrogen adsorption suggesting the presence of mesoporosity. The sorption of the bigger molecule like triisopropylbenzene... 

Benzene, naphthalene and phenanthrene Partition Merck SI 60 + added water n-Hexane... 

When the mutual immiscibihty of two components becomes large, the locus of liquid-liquid critical solution moves to higher temperatures and it eventually interacts with gas-liquid critical cmwe disrupting the gas-liquid locus. This particular class is type III and some examples include water + n-hexane, water + benzene, carbon dioxide + n-tridecane, and carbon dioxide + water. 

Figure 4. Pressure-temperature-composition (p,Tx,) diagram in the critical region of the binary system water-n-hexane, calculated and experimental. x(H20) is the mole fraction of water. The two-phase region is at the low-temperature side of the critical curve [68,69].

Tian, Tiling, Michelberger, Th., and Franck, E.U. (1991), High pressure phase equilibria and critical curves of (water-n-butane) and (water-n-hexane) to temperatures of 700 K and pressures to 300 MPa, J. Chem. Thermodynamics 23, 105-112. 

Isomeric polyphenols P. laetevirens CCC Light petroleum -ethyl acetate-methanol-water n-hexane-ethyl acetate-methanol-water ESI-MS, H-RMN, C-RMN [131]... 

Figure 2.24(a) Diagrammatic representation of the effect of progressively adding water to a mixture of PNE, PFE and n-hexane. L, liquid Gg, gel E, emulsion Mj, middle phase liquid crystal G, neat phase liquid crystal, (b) Diagrammatic quaternary phase diagram for the system PNE-PFE-water-n-hexane at 25° C. From Groves et al [42] with permission. 

Properties Gardner < 5 pasty solid weak odor sol. in chloroform, methylene chloride sparingly sol. in ethanol disp. in water, n-hexane insol. in min. oils m.p. 32-37 C HLB 11.0 acid no. < 6 iodine no. < 3 sapon. no. 65-85 100% cone. 

Water/n-hexane Distribution between two immiscible liquid countercurrent 520,521... 

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