Magnesium partitioning

Obata, M., Banno, S. Mori, T. (1974) The iron-magnesium partitioning between naturally occurring coexisting olivine and Ca-rich clinopyroxene an application of the simple mixture model to olivine solid solution. Bull. Soc. Franc. Mineral., 97,101-7. 

To a solution of the ester amide (160 mg, 0.26 mmol) in methanol (3 mL) and THF (3 mL) was added a 1 M solution of NaOMe in methanol (5 mL). The mixture was stirred at rt for 1.5 d then neutralized with methanolic acetic acid and concentrated in vacuo. The crude material was partitioned between water and CH2CI2. The organic phase was dried over anhydrous magnesium sulfate, filtered, and concentrated in vacuo to afford the bis(ester) 73 as a colorless solid, mp 154.4-155.5 C, [a] -17° (c = 0.3, MeOH). 

Early experimental work in electrorefining at Los Alamos by Mullins et-all ) demonstrated that americium could be partitioned between molten plutonium and a molten NaCl-KCl salt containing Pu+3 ions, and Knighton et-al(8), working at ANL on molten salt separation processes for fuel reprocessing, demonstrated that americium could be extracted from Mg-Zn-Pu-Am alloys with immiscible molten magnesium chloride salts. Work... 

C. (Z)-[2-(Fluoromethylene)cyclohexyl]benzene (3). To a solution of (fluorovinyl)stannane 2 (26.0 g, 0.054 mol) in dry THF (150 mL) is added 65 mL of 1 M sodium methoxide in methanol (prepared by the addition of 1.50 g (0.065 g-atom) of sodium to 65 mL of methanol). The solution is refluxed for 18 hr under nitrogen (Note 14), cooled to ambient temperature and concentrated on a rotary evaporator. The residue is partitioned between water (200 mL) and hexane (200 mL). The aqueous layer is separated and extracted with hexane (100 mL). The combined organic layers are dried (magnesium sulfate) and concentrated on a rotary evaporator to give a colorless oil (30 g). Kugelrohr distillation gives 10.0-10.2 g (97-100%) of fluoro olefin 3 (bp 85-90°C, 0.4 mm) as a colorless oil (Note 15). 

The conversion of the m-monoolefin to its silver nitrate complex 1 was accomplished by adding 1.66 g. (0.010 mole) of the distilled reaction product to a solution of 1.70 g. (0.010 mole) of silver nitrate in 50 ml. of boiling methanol. The resulting solution, when cooled, deposited the complex as white needles, m.p. 79° dec. recrystallization from methanol separated 1.0 g. of the complex, m.p. 80° dec. After this complex had been partitioned between water and ether, the ether phase was separated, dried over magnesium sulfate, and concentrated. Distillation of the residual liquid in a short path still separated 0.45 g. of the pure (Note 6) cfs-cyclodecene, b.p. 70° (1.0 mm.), n B 1.4852. 

Nishizawa O. and Akimoto S. (1973). Partitioning of magnesium and iron between olivine and spinel, and between pyroxene and spinel. Contrib. Mineral Petrol, 41 217-240. 

Oka Y. and Matsumoto T. (1974). Study on the compositional dependence of the apparent partitioning coefficient of iron and magnesium between coexisting garnet and clinopyro-xene solid solutions. Contrib. Mineral. Petrol, 48 115-121. 

Wood B. J. (1976b). The partitioning of iron and magnesium between garnet and clinopyro-xene. Carnegie Inst. Wash. Yb., 75 571-574. 

B. Ethyl pyrrole-2-carboxylate. In a 1-1. three-necked round-bottomed flask equipped with a sealed mechanical stirrer and powder funnel are place 1.0 g. of sodium and 300 ml. of anhydrous ethanol. When the sodium is dissolved, 75 g. (0.35 mole) of pyrrol-2-yl trichloromethyl ketone from Part A is added portionwise over a 10-minute period (Note 4). After the addition is complete, the solution is stirred 30 minutes, then concentrated to dryness using a rotary evaporator. The oily residue is partitioned between 200 ml. of ether and 25 ml. of 3 N hydrochloric acid. The ether layer is separated, and the aqueous layer is washed once with 100 ml. of ether. The ether solutions are combined, washed once with 25 ml. of saturated sodium bicarbonate solution, dried with magnesium sulfate, and concentrated by distillation. The residue is fractionated at reduced pressure to give 44.0-44.5 g. (91-92%) of ethyl pyrrole-2 carboxylate as a pale yellow oil, b.p. 125-128° (25 mm.) (Note 5). The yield based on pyrrole is 70-74%. Upon standing at room temperature the product crystallizes, m.p. 40-42°. 

At the third level, the most detailed partition of luminescence minerals is carried out on the basis of metals in the mineral formulae, hi rare cases we have minerals with host luminescence, such as uranyl minerals, Mn minerals, scheelite, powellite, cassiterite and chlorargyrite. Much more often luminescent elements are present as impurities substituting intrinsic cations if their radii and charges are close enough. Thus, for example, Mn + substitutes for Ca and Mg in many calcium and magnesium minerals, REE + and REE substitutes for Ca, Cr substitutes for AP+ in oxygen octahedra, Ee substitutes for Si in tetrahedra and so on. Luminescence centers presently known in solid-state spectroscopy are summarized in Table 4.2 and their potential substitutions in positions of intrinsic cations in minerals in Table 4.3. 

The partition of salts between the soluble and colloidal phases is summarized in Table 5.5. In general, most or all of the sodium, potassium, chloride and citrate, one-third of the calcium and two-thirds of the magnesium and about 40% of the inorganic phosphate are in the soluble phase. 

Not all of the salt constituents are found in the dissolved state in milk. Calcium, magnesium, phosphate, and citrate are partitioned between the solution phase and the colloidal casein micelles (see Chapter 9 for the composition and structure of these micelles). For analytical purposes, partition of the salt constituents can be achieved by equilibrium dialysis or by pressure ultrafiltration. In the latter technique, pressures must be limited to about 1 atmosphere to avoid the so-called sieving effect (pushing water through the filter faster than the dissolved components (Davies and White 1960). 

To a solution of LDA (40mmol) in THF (200ml) cooled at -45°C, methyl dithioacetate (3.92 ml, 40 mmol) was added dropwise. The yellow colour rapidly disappeared. The mixture was stirred for 5 min. 2-Cyclohexenone (3.92 ml, 40 mmol) was then added dropwise. A yellow colour appeared. The resulting mixture was stirred for 15 min. An aqueous solution of ammonium chloride was added and the mixture partitioned between ether and brine. The organic layer was washed with brine, dried with magnesium sulfate and concentrated. Methyl (cyclohexanone-3-yl)dithioacetate (3) (6.75 g, 33.4 mmol, 83%) was isolated by flash chromatography on silica gel using cyclohexane/ethyl acetate (9 1) as the eluent. 

Dibenzyl malonate (124.5 g, 0.44 mol) was taken up in dry DMF and potassium t-butoxide (49.2 g, 0.44 mol) was added portionwise with stirring and cooling. When a homogeneous solution had formed it was cooled to 0°C, then t-butyl-2R-bromo-5-methylpentanoate (110.1 g, 0.44 mol) in DMF (200 ml) was added dropwise over 1 h. When addition was complete the reaction was transfered to a cold room at 5°C and left for 4 days. The reaction mixture was partitioned between ethyl acetate and saturated ammonium chloride then the aqueous layer extracted with further ethyl acetate (4 x 500 ml), drying and solvent removal left an oil (228.0 g) heavily contaminated with DMF. This oil was taken into ether (1 L) and washed with brine (2 x 11) then the organic layer dried (magnesium sulfate), solvent removed under reduced pressure to leave the benzyl (2-benzyloxycarbonyl-3R-(t-butoxycarbonyl)-5-methylhexanoate (179.0 g) contaminated with a small amount of dibenzyl malonate. 

To a solution of N-methyl-4-nitrophenethylamine (1.5 g) (J.O.C., [1956], 21, 45) and 2-[4-nitrophenoxy]ethyl chloride (1.55 g) (C.A., [1955], 49, 3163e) in acetonitrile (50 ml) was added potassium carbonate (1.25 g) and sodium iodide (1.2 g) and the suspension was stirred at reflux for 72 hours. After evaporation to dryness, the residual oily solid was partitioned between a 2 N aqueous sodium bicarbonate solution and ethyl acetate. After two further extractions with ethyl acetate, the organic portions were combined, washed with a saturated aqueous brine solution, dried over magnesium sulfate, filtered and evaporated. The resultant orange solid (2.7 g) was crystallised from ethanol to give l-(4-nitrophenoxy)-2-[N-methyl-N-(4-nitrophenethyl)amino]ethane (1.9 g), m.p. 74°C. 

---