Lower brine layer

Figure 7. Relative increase in the concentration in the upper brine layer (AC/C) owing to river inflow and eddy diffusional transport of salt from the lower brine layer in the Dead Sea. Concentration increment (AC) computed from Equation 29 for time steps (At) 50 and 100 years. Relative increase shown as a function of increasing concentration in the upper brine layer (C).

Figure 9. Fraction of increase in the concentration of the upper water mass (Dead Sea) owing to eddy diffusional transport of salt from the lower brine layer. Computed from Equation 30 for three different values of the surface salt input as identified in Figure 8...

North American Chemical Co. produces borax pentahydrate and decahydrate from Seades Lake brines in both Trona and West End, California (see Chemicals frombrines). The 88 km dry lake consists of two brine layers, the analyses of which are given in Table 11. Two distinct procedures are used for the processing of upper and lower lake brines. Borax is produced in Trona from upper lake brines by an evaporative procedure involving the crystallization of potash and several other salts prior to borax crystallization as the pentahydrate (104). A carbonation process is used in West End, California to derive borate values from lower lake brines (105). Raw lower stmcture brine is carbonated to produce sodium bicarbonate, which is calcined and recrystallized as sodium carbonate monohydrate. The borate-rich filtrate is neutralized with lake brine and refrigerated to crystallize borax. 

Twelve grams of the magenta dye 61 was dissolved in 250ml of methylene chloride and stirred gently with a solution of 12.2g of sodium dithionite in 250 ml of water. A solution of 5 g of benzoyl chloride in 10 ml of dichloromethane was added slowly to the lower organic layer. The pH of the upper aqueous layer was maintained at 5 to 6. The organic layer was separated, washed with dilute aqueous NaOH and brine. The solution was absorbed onto silica gel and rotary evaporated to dryness. The product was washed from the silica with ether. The ether solution was evaporated to yield 8.2 g of the leuco dye 3-(A-benzyl-A-methyl)amino-9-ethyl-l0-ben-zoyl-9,10-dihydrophenazine (62). 

We turn our attention now to the hydrothermal brines of the Red Sea. An oceanic survey in 1963 discovered pools of hot, saline, and metal-rich brines along the axial rift of the Red Sea (Degens and Ross, 1969 Hoffmann, 1991). The dense brines pond in the rift s depressions, or deeps. The Atlantis II deep contains the largest pool, which measures 5 x 14 km and holds about 5 km3 of supersaline brine. The deep holds two layers of brine. The lower brine contains about 25 wt.% dissolved salts and exists at temperatures up to 60 °C. Table 6.8 shows the brine s average composition. A somewhat cooler, less saline water overlies the lower brine, separating it from normal seawater. 

Initially, this Martian brine was equilibrated at Pco2 = 50 mbars within each of the ten layers. Under these conditions, virtually all the Fe (99.99%) precipitates as siderite (FeCOo), and 77.6 to 96.6% of the Ca precipitates as calcite (CaCOo) (Fig. 5.18). After equilibration of each 0.5-km layer separately, we then froze the profile from the top down, layer by layer, assuming that the freezing process would be sufficiently slow that all soluble salts would be ejected into the lower, unfrozen, layers. This process leads to increasing salt concentrations with depth (Fig. 5.18). These freezing simulations were done assuming that all Fe was removed in the initial evaporative concentration. Freeze concentration leads to the additional precipitation of calcite and... 

Extract with dichloromethane (3 x 50 mL), combine the lower organic layers and wash them with 1 M HCI (50 mL) and brine (3 x 50 mL). 

Dissolve the solid residue in 100 mL of dichloromethane and transfer to a separating funnel. Wash the lower organic layer twice with 50 mL of water and once with the same volume of brine. Dry the dichloromethane solution with magnesium sulfate, filter and evaporate. 

In order to estimate how long would it take for the Dead Sea water column to become homogeneous, beginning with its present concentration difference between the upper and lower layer, it is necessary to know how the volume of the individual brine layers and rate of salt input vary with time. As these relationships are not known, the following assumptions will be made ... 

U.W.M. and L.W.M. are the upper and lower water masses, or brine layers. Computation for a three-layer model assumes a hypothetical concentration of 100 grams/liter in the upper water mass at time t — 0. Three concentration-time curves computed for different values of the salt input by surface inflow Curve Cj for concentration and discharge as the present mean River Jordan, and curves for twice and four times the present rate of salt input. Equation... 

The mixture was transferred into a separating funnel. The lower aqueous phase was separated and extracted with u-hexane (4 x 20 mL). The brown combined organic layers were washed with water (3 x 30 mL) and twice with brine (2 x 30 mL), dried over sodium sulfate, filtered and concentrated under reduced pressure, giving a brown oil (180 mg). 

When the reaction is completed, the agitation is stopped and a taffy (which is an emulsion of about 30 per cent water in resin) rises to the top of the reaction mixture. The lower layer of brine is removed, the resinous layer gets coagulated and washed with hot water, clarified by passing through a filter and finally allowed to solidify. 

Asahi s investigations showed that a Na+ concentration of 1.1 N was necessary in compartment II to maintain a current efficiency of 96% in the carboxylic membrane during operation with 3.5 N brine in compartment I and 32% caustic soda in compartment III. The Na+ concentration in compartment II was generally far lower than that in compartment I, and clearly indicates the tendency for depression of the Na+ concentration at the interface of the sulphonic and carboxylic layers in the normal... 

The acidic aqueous layer from the aqueous acetic acid/sodium acetate/pentane hydrolysis of 2-alkylcyclo-hexanonc imines is neutralized with solid potassium hydroxide to pH 14, and then saturated with sodium chloride. This aqueous solution is extracted with four portions of diethyl ether, and the combined ethereal layer is washed with brine. Drying over potassium carbonate and concentration gives an oil which is distilled 85% recovery bp 57-59 °C/0.02 Torr [x]D — 13.75 (c = 5.8, benzene). If the rotation of the distilled amine is lower than 13.40, it is purified via its hydrochloride. Thus, a solution of the amine in ice-cold diethyl ether is treated with dry hydrogen chloride by bubbling through a fritted disk. The amine hydrochloride is collected by filtration and recrystallized from ethanol mp 151-152°C. 

Even with this unequal distribution there may be little effect on yield of distillate from a substantially fresh water feed hence the high output of the still from distilled water feed. With sea water, 3 to 4% NaCl equivalent, the average or effective boiling point elevation becomes unequal on the two rotors. Thus if a 50% cut is secured and the lower rotor receives twice the feed of the upper, the average residue concentrate of 7% brine from 3.5% feed could be an actual 10% from the upper periphery and 5% from the lower, supposing equal rates of distillation. Actually because of -the different elevations of boiling point (1.1° and 1.8° F.) the rate of evaporation from the upper rotor decreases while that from the lower rotor increases but less than proportionally because of the added thickness of the feed layer. Later experiments at Columbus on the No. 4 machine suggest that this situation existed in the No. 5 still. 

The inside of the cathode is lined with asbestos paper 0.G mm thick. To achieve uniform permeability for brine three layers of paper are used in the lower part of the electrode and only two in the upper part. 

The Step 5 product (14 mmol) dissolved in 50 ml DMF was treated with K2C03 (42 mmol) and di-f-butyldicarbonate (14 mmol), then stirred 19 hours at ambient temperature, and concentrated. The residue was mixed with 100 ml apiece water and diethyl ether and the layers were then separated. The aqueous phase was extracted twice with 100 ml diethyl ether and extracts saved. The aqueous phase was then cooled to 0°C and re-extracted with 200 ml EtOAc. The aqueous phase pH was lowered to 3 with 1M HC1 and the solution further extracted with 100 ml EtOAc. The combined extracts were washed with 50 ml brine, dried with Na2S02, and concentrated. The residue was purified by flash chromatography using 5% methyl alcohol/CH2Cl2/0.5% HOAc and the product isolated in 92% yield as a white foam. 

The Step 6 product (1.94 mmol) was slowly added to a solution of KMn04 (2.13 mmol) in 6 ml 2% aqueous KOH at 60°C and the temperature gradually raised to 90°C over 90 minutes. The mixture was then cooled to 0°C and treated with 50 ml EtOAc and 1M HC1 to lower the pH to 3. Layers were separated and the aqueous portion further extracted with 50 ml EtOAc. Extracts were washed with brine, dried over Na2S04, and concentrated. The residue was purified by flash chromatography using 2% (200 ml), 3% (200 ml), 4% (200 ml), and 5% (500 ml) methyl alcohol/CH2Cl2 and 0.5% HOAc and the product isolated in 51% yield as a white solid. 

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