Dehydrating power

ACETOACTETIC ESTER CONDENSATION. A class of reactions occasioned by the dehydrating power of metallic sodium or sodium ethoxide on the ethyl esters ol monobasic aliphatic acids and a tew other esters. It is best known in the fonuation of acecoacetic ester ... 

Chlorine dioxide can be made by carefully adding sulfuric aad to potassium chlorate, KCIO3. It would be expected that this mixture would react to produce chloric acid, HCiOg, and then, because of the dehydrating power of sulfuric acid, to produce the anhydride of chloric acid, ClgOg ... 

Hydrazine is generally obtained by reaction in the aqueous phase. It is subsequently concentrated by successive evaporations and rectifications and then, in order to eliminate the water to the maximum extent, one of the methods most recently employed consists in using the dehydrating power of alkaline or alkaline-earth substances, such as caustic soda, potash, or alkaline-earth oxides (quicklime of barium oxide). It is then separated from the dehydrating agent by distillation. 

The acidity of the mixed acids, not their dehydrating power, has been established as being the rate criterion for the formation of true nitro compounds that it might be extended to the case of nitric esters seems a reasonable assumption. ... 

Some activation is due to the dehydrating power of the phosphoric acid and, to this extent, the method is analogous to the zinc chloride process. Frequently, the charred product is subsequently ignited for 2 to 8 hours in retorts at 800° to 1,000° C. During this latter stage, the carbon is eroded by being partly oxidized by the phosphoric acid which is reduced to phosphorous and hydrides. These vaporized products are subsequently oxidized to phosphoric acid to repeat the cycle with a fresh batch of raw material. 

The dehydrating power of salts in any salting out operation in which there is a solid salt phase present is, at any given temperature, in inverse relation to the vapour pressure of water over the salt s solution in pure water (Table 7.14). 

Several chemical, rather than physical approaches, to water and solvent separation are used in both small-and industrial-scale operations. Salting out relies on the use of a solid form, or highly saturated aqueous solution, of an electrolyte which on contact with a mixture of water and solvent will withdraw the water from the solvent and form a second phase. Separation is then achieved by decanting the two liquids. Chlorides and sulphates of Group 2 metals are commonly used as the electrolyte primarily due to their low cost, dehydrating power and the absence of reaction with common solvents. 

Based on its availability and structural nature, investigation of the " dehydrating power of o-sulfobenzoic acid anhydride (I) was carried out The parent add may be readily available as an intermediate in the synthesis of saccharin (5). The cyclic nature of this anhydride along with its half sulfonic/ half benzoic composition hinted to us that it may prove to be a suitable compound for the present isocyanate technology. 

In the preparation of the linear analogues, solvents such as nitrobenzene [478] and methylene chloride [479] were used. A new method capable of creating poly(ether ketone) and polyfthioether ketone) was recently disclosed by Ueda et al. [480-482]. Here, the dehydrating power of a mixture of phosphorus pentoxide and methanesulfonic acid (MSA) is the driving force for the direct polycondensation of aromatic dicarboxylic acids with aryl compounds contain-... 

Sodium dichromate [7789-12-01 M 298.0, m 84.6" (IHiO), 356" (anhydr) b 400"(dec), 64 2.348. Crystd from small volumes of H2O by evaporation to crystallisation. Solubility in H2O is 238% at 0° and 508% at boiling. Red dihydrate is slowly dehydrated by heating at 100° for long periods. It is deliquescent, a powerful oxidising agent-contact with skin- wash immediately as it is caustic. (Possible carcinogen). 

Liquid sulfur trioxide may be purchased in stabilized form as Sulfan B," m.p. 17°, b.p. about 45°. Caution must be exercised in handling sulfur trioxide. The liquid is highly corrosive to the skin and the vapor may cause injury if inhaled. The powerful oxidizing and dehydrating effects of sulfur trioxide should not... 

The powerful dehydrating ability of sulfuric acid is seen when a little concentrated acid is poured on sucrose, Ct2H220M. A black, frothy mass of carbon forms as a result of the extraction of H20 (Fig. 15.17) ... 

The steric bulk of steroid structures prevents their use as the only organic side group present. However, mixed-substituent polymers that contain both steroidal side groups and amino acid ester or other cosubstituent units can be readily synthesized. If a saturated A ring is present in the steroid, linkage to the polymer chain is complicated by side reactions that result from dehydration of the steroid (chlorophosphazenes are powerful dehydrating agents). 

Most of the numerous and frequent hazards experienced with perchloric acid have been associated with either its exceptional oxidising power or the inherent instability of its covalent compounds, some of which form readily. Although the 70-72% acid of commerce behaves when cold as a very strong, but non-oxidising acid, it becomes an extreme oxidant and powerful dehydrator at elevated temperatures (160°C) or when anhydrous [1],... 

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