Hydration solutions

Hydrazine hydrate may be titrated with standard acid using methyl orange as indicator or, alternatively, against standard iodine solution with starch as indicator. In the latter case about 0-1 g., accurately weighed, of the hydrazine hydrate solution is diluted with about 100 ml. of water, 2-3 drops of starch indicator added, and immediately before titration 6 g. of sodium bicarbonate are introduced. Rapid titration with iodine gives a satisfactory end point. 

For calculations involving hydrated salts, it is convenient to make the calculations based on the hydrated solute and the free water, ... 

In a 500-cc. round-bottom flask fitted with a reflux condenser are placed 68 g. of phenylurea (0.5 mole) (Note i) and 120 cc. (i mole) of 42 per cent hydrazine hydrate solution (Note 2). The flask is heated on a steam bath for about twelve hours. The hot mixture is treated with a small amount of decolorizing charcoal (Norite) and filtered. The charcoal is washed with two 15-CC. portions of warm water and the filtrate and washings are then concentrated on a steam bath to about 100 cc. On coolipg in an ice bath a crop of crystals separates and is collected on a filter and washed with two 15-cc. portions of cold water. The filtrate and washings are concentrated to about 25 cc. and another crop of crystals is obtained as before. The total yield of crude compound is 47-52 g. It is white at first but sometimes turns brown on drying. It usually melts below 115° because of some unchanged phenylurea. 

An equivalent amount of hydrazine sulfate and sodium hydroxide in 80 per cent alcohol may be used in place of the hydrazine hydrate solution without greatly diminishing the yield. 

Almost simultaneously, Sehroth reported that diaeetylene reaets with a hydrazine hydrate solution at 80°C for 4 h to form methylpyrazoles (13) in 80% yield (69ZC108 69ZC110). In the same year, other data eoneeming the reaetion of hydrazine with diaeetylene (65°C, EtOH, yield 65%), hexa-2,4-diyne, and 1,4-diphenylbuta-1,3-diyne were reported (69JOC999). Later, BASF (93GEP4137011) proposed to earry out the proeess at 100°C in a polar solvent with a diaeetylene eoneentration of 14-18% in an inert gas. The yield of methypyrazoles was 90% (post-reetifieation purity 99%). 

The semi-carbazone melts at 234°, and has a specific rotation -t- 317° in chloral hydrate solution. 

The 42 per cent hydrazine hydrate solution supplied by the Eastman Kodak Company is too dilute for use as such, but may be concentrated by distillation with xylene.1 A mixture of r44 cc. (150 g.) of the 42 per cent solution and 230 cc. of xylene is distilled from a 500-cc. flask through a 17-cm. Hempel column fitted into a cork covered with tin foil. After distillation of the xylene, with about 85 cc. of water, the residue yields on distillation 45-50 g. of 80-85 per cent hydrazine hydrate. This material, assayed best by titration with standard acid using methyl orange as indicator, may be used as such or concentrated further (see Note 6). 

We note that the calculation of At/ will depend primarily on local information about solute-solvent interactions i.c., the magnitude of A U is of molecular order. An accurate determination of this partition function is therefore possible based on the molecular details of the solution in the vicinity of the solute. The success of the test-particle method can be attributed to this property. A second feature of these relations, apparent in Eq. (4), is the evaluation of solute conformational stability in solution by separately calculating the equilibrium distribution of solute conformations for an isolated molecule and the solvent response to this distribution. This evaluation will likewise depend on primarily local interactions between the solute and solvent. For macromolecular solutes, simple physical approximations involving only partially hydrated solutes might be sufficient. 

According to Cairns-Smith, the first primitive gene materials could have been clay minerals these crystallize out everywhere on Earth from dilute silica solutions and hydrated solutions of metal ions. Both groups of substances are continually being formed by weathering processes. Two cycles keep this dynamic process going ... 

Using pyranine (8-hydroxy-1,3,6-pyrene trisulfonate) as intraliposome pH indicator, the liposomes were prepared as above (as in section Preparation of 100 nm SSL Loaded with DOX via Transmembrane AS Gradient ) with the exception that pyranine (0.5 mM) was included in the hydration solution. Removal of untrapped pyranine was achieved by gel filtration on a Sephadex G-50 column, preequilibrated with either NaCl, KCl, sucrose or AS solution (according to need). All these solutions also contained lOmM Hepes buffer at the desired pH (usually pH 7.5). 

Malonic Acid. 100 g of powdered chloroacetic acid is treated with 150 g of broken ice and dissolved in 125 g of caustic soda (33 A%) solution. The solution should be made exactly neutral, if it is not already (this refers to the mixture). After neutralizing, add 69 g of 98% potassium cyanide in 130 g of water, which has been warmed to 40°. An hour after the addition, the mixture is slowly warmed to 100° and held at this temp for an hour. Cool slowly to 25° and add another 125 g of SSV4% caustic soda solution. Slowly heat the mixture to 100° and hold at that temp until no more ammonia is evolved (2 to 3 hours). To test add sodium hydrate solution to a sample and boil. If no ammonia evolves, then the reaction is complete. When the reaction is complete, the solution is cooled, acidified with dilute HCl acid, and carefully evaporated to complete dryness on a water bath. The residue is powdered, extracted repeatedly with ether, and the ether... 

Sodium chloride (hypotonic) - 0.45% Sodium chloride (hypotonic) is primarily a hydrating solution and may be used to assess the status of the kidneys, because more water is provided than is required for salt excretion. It also may be used in the treatment of hyperosmolar diabetes where the use of dextrose is inadvisable and there is a need for large amounts of fluid without an excess of sodium ions. 

CNOl9 Neto, U. F., L. Franco, K. Tabacow, and N. L. Machado. Negative findings for use of coconut water as an oral re-hydration solution in childhood diarrhea. J Amer Coll Nutr 1993 12(2) 190-193. 

To a flask equipped with a reflux condenser are added 68 gm (0.5 mole) of phenylurea and 120 ml (1.0 mole) of 42 % hydrazine hydrate solution. The mixture is refluxed for 12 hr, filtered hot using decolorizing charcoal, and then concentrated to 100 ml. On cooling, the crystalline product separates and it is washed with the minimum amount of water. The filtrate is concentrated to 25 ml and another crop of crystals is collected. The total yield of the crude... 

Very stable colloidal solutions of selenium may be prepared by the regulated action of concentrated hydrazine hydrate solution on selenium dioxide or grey crystalline selenium and subsequent dilution of the solutions with water and purification by dialysis. According to the degree of dispersion the colour of the solutions varies from intense yellow to blood red. These sols are completely irreversible. The dilute solutions are stable at the boiling-point, but are readily coagulated by barium sulphate. Sodium and potassium carbonates appear to increase the stability of the system. 

One gram of U.S.P. gum arabic is dissolved in 70ml of hot water. After cooling, O.lg of copper sulfate 5-hydrate ia dissolved in the liquid and 30ml of concentrated ammonia are added. The blue solution is warmed to 50°C and a few milliliters of a 0.0005% hydrazine hydrate solution are added. A copper sol ia produced which ia the color of the metal by reflected light and blue by transmitted light The colloidal suspension must be dialyzed for several days immediately after it is prepared and it ia stable for only a short time. 

Hydrazine monohydrochloride may be purchased commercially. Alternatively, it may be prepared by adding concentrated hydrochloric add dropwise, with stirring, into a well-cooled hydrazine hydrate solution until the pH is about 7 (Alkacid paper). The solution is evaporated to the point of crystallization and cooled. The product which separates is collected by filtration. The resulting solid has a high water of crystallization but is perfectly suitable for the preparation of heraammineruthenium (III) salts. 

Ulsch2 has made some observations on the complete electrochemical oxidation of cane sugar to carbonic acid and water. In a sulphuric acid of 1.15 sp. gr., with the addition of manganese sulphate as an oxygen-carrier, about 98% of the theoretically calculated amount of carbonic acid is obtained. The oxidation at 40°-80° in barium-hydrate solution is also fairly complete, but not directly to carbonic acid oxalate appears also to be formed. 

Dimethyluric Acid gives similarly a 3.9-dimethylpuron which, if heated in a 10% sodium-hydrate solution, smoothly rearranges itself to form the iso-compound. The electrolytical effect is hence a normal one ... 

Pt-C (by Kaffer).158 To 10-12 g of active carbon mixed well with water is added an aqueous solution of the calculated amount of chloroplatinic acid. The mixture is warmed on a water bath for a few hours at 50°C. After cooling, a concentrated sodium carbonate solution is added until the mixture becomes alkaline. Then a hydrazine hydrate solution is added drop by drop under stirring. Whether the amount of hydrazine is sufficient to reduce the chloroplatinic acid can be readily determined by the decoloration of a permanganate solution. The platinum-carbon suspension is further warmed for 1-2 h on a water bath, filtered, and washed with hot water until the washing is free from chloride and alkali. After dried as fully as possible between filterpapers, the catalyst is dried for half a day over calcium chloride in vacuum. Kaffer used a 10% Pt-C thus prepared for the dehydrogenation of decalin and found it much more effective than Pt-asbestos by Zelinsky. Newhall used a 5% Pt-C by Kaffer for... 

SODA LYE SODIUM HYDRATE, solution SODIUM HYDROXIDE, solution (I- CC) WHITE CAUSTIC, solution... 

The reaction is carried out by heating the ester with 40% aqueous hydrazine hydrate solution. The yields of hydrazides are usually excellent from aliphatic and aromatic esters. The procedure is well il-... 

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