Water solvent action

For purification, transfer the acid to a 150 ml. flask containing 60 ml. of water, boil the mixture under reflux, and then add acetic acid in 5 ml. portions down the condenser until almost all the solid has dissolved avoid an excess of acetic acid by ensuring that the solvent action of each addition is complete before the next portion is added. A small suspension of insoluble impurity may remain. Add 2 g. of animal charcoal, boil the solution again for 10-15 minutes, and then filter it through a preheated Buchner funnel. Cool and stir the filtrate, which will deposit pale cream-coloured crystals of the acid. Collect as before and if necessary repeat the recrystallisation. Yield of pure acid, 9 g. m.p. 227-229°. 

In unalloyed steel containers formamide discolors slowly during shipment and storage. Both copper and brass are also subject to corrosion, particularly in the presence of water. Lead is less readily attacked. Aluminum and stainless steel are resistant to attack by formamide and should be used for shipping and storage containers where the color of the product is important or when metallic impurities must be minimized. Formamide attacks natural mbber but not neoprene. As a result of the solvent action of formamide, most protective paints and finishes are unsatisfactory when in contact with formamide. Therefore, formamide is best shipped in containers made of stainless steel or in dmms made of, or coated with, polyethylene. Formamide supphed by BASF is packed in Lupolen dmms (230 kg) or Lupolen canisters (60 kg) both in continental Europe and overseas. 

Thiolates, generated in situ by the action of ammonium tetra-thiomolybdate on alkyl halides, thiocyanates, and disulfides, undergo conjugate addition to a, (1-unsaturatcd esters, nitriles, and ketones in water under neutral conditions (Eq. 10. II).29 Conjugate addition of thiols was also carried out in a hydrophobic ionic liquid [bmim]PF6/water-solvent system (2 1) in the absence of any acid catalyst to afford the corresponding Michael adducts in high to quantitative yields with excellent 1,4-selectivity under mild and neutral conditions (Eq. 10.12). The use of ionic liquids helps to avoid the use of either acid or base catalysts... 

Applying the mass action law and assuming unitary activity for the water solvent and the condensed phase, we obtain... 

Hydrofluoric acid like water is an associated liquid, and even the gas, as we shall soon see, is associated. It has the power of uniting with fluorides. It also seems to be an ionizing solvent for a soln. of potassium fluoride in liquid hydrogen fluoride is an excellent conductor it also possesses marked solvent powers. According to E. C. Franklin,7 the liquid readily dissolves potassium fluoride, ehloride, and sulphate sodium fluoride, bromide, nitrate, chlorate, and bromate acetamide and urea. The solvent action is not so marked with barium fluoride, cupric chloride, and silver cyanide while calcium and lead fluorides copper sulphate and nitrate ferric chloride, mercuric oxide, and magnesium metal, are virtually insoluble in this menstruum. Glass also is not affected by the liquid if moisture be absent. The liquid scarcely acts on most of the metals or non-metals at ordinary temp., though it does act on the alkali metals at ordinary temp., much the same as does water, with the simultaneous production of flame. 

N. A. E. Millon found that a soln. of alkali chlorite gives a yellow precipitate of lead chlorite, Pb(C102)2, or of silver chlorite, AgC102, when treated respectively with lead or silver nitrate. On recrystallization from hot water, lead and silver chlorites are obtained in yellow plates. J. Schiel also made lead chlorite by treating a soln. of barium or calcium chlorite with lead nitrate an excess of the lead nitrate is to be avoided because of its solvent action. Fine sulphur yellow crystals can be obtained from a warm soln.—50°-60°—of the salt in calcium chlorite. The dry salt explodes at 126° according to N. A. E. Millon, at 100° according to J. Schiel. It explodes when triturated with flowers of sulphur or antimony sulphide. It behaves like silver chlorite with hydrogen sulphide and with sulphuric acid. 

The great solvent power of water, especially for ionic compounds, is due to its dielectric constant. If this were only, say 10, instead of the actual 80, it would mean that water could dissolve only a trace of sodium chloride. This solvent action of water., naturally. plays an important role in geology. In biology, water functions as a means of conveying salts and other substances which circulate in the bodies of animals and plants. It is outside the scope of this book to discuss any further the function of water on this planet, a subject which could fill many volumes. It is important in this context that we now know water molecules to possess a dipole moment and to discover whether perhaps this fact can provide an explanation of the unique properties of water. 

It has been previously slated that ammonia is one of the principal produets of the decomposition of anima] matter. This ammonia very speedily becomes oxidized aud converted into nitrous acid—N 03—which, by longer exposure, is further oxidised Into nitric acid —NO, The above-mentioned acids depend for their origin ou the presence of. organic matter copable of yielding ammonia, and the solvent action of waters upon load, is almost entirelydue to these acids. 

The distillate here described as obtained from the retort at redness would be a mixture of sulphuric and nitric acids, and by the addition of the ammonium chloride, hydrochloric acid. The solvent action of this acute or sharp water makes much more comprehensible the chemistry of many processes described, than if we assumed that the vegetable acids were the only ones used. It is probable that this is by no means Geber s invention, but he is perhaps the first who describes the preparation so clearly and comprehensibly. 

The term solvent action is understood (o mean any process of making substances water soluble but in a broader interpretation the term is understood to be the phenomenon of making a substance soluble in a solvent. Solvent power, diluting power, solvency and similar expressions indicate the property of solvents to disperse the molecules of a solute or vehicle therehy causing a decrease in viscosity. 

A limitation of both methods is that the second component must be liquid at the temperature of-the reaction, which is 5-10° for the diazohydroxide reaction and room temperature or slightly higher for the nitrosoacetylamine reaction. Experiments with solid reactants in solution have not been very successful, because of the difficulty of finding a suitable solvent. The solvent should be neutral and immiscible with water, have a high solvent action and reasonably low boiling point, and be inert to the free radicals which result from the diazo compound. The last qualification is the most difficult one to satisfy. Of the solvents which have been tried, carbon tetrachloride and chloroform appear to be the most suitable.18 From diazotized aniline and biphenyl in these solvents, some p-terphenyl is obtained, and from diazotized p-nitroaniline and biphenyl a small amount of 4-nitro-4 -phenylbiphenyl is formed. In these reactions an appreciable amount of tfie aryl halide (chlorobenzene and p-nitrochlorobenzene) is produced as a by-product. In general, the yields of products obtained by coupling with reactants in solution are extremely low. 

Water is characterised by powerful solvent action, particularly as regards many inorganic substances. 

In the strictly scientific sense of the word insolubility does not exist, and even those substances characterized by the most obstinate resistance to the solvent action of water may properly be designated as extraordinarily difficult of solution, not as insoluble. 

Water, it may be recalled (Chapters 2 and 4), has two modes of solvent action, depending on the nature of the added electrolyte. The water can contact an ionic crystal (e.g., NaCl), detach the ions from the lattice through the operation of ion-dipole (or ion-quadrupole) forces, and convert them to hydrated ions (Chapter 2). 

There is a further analogy between the solvent actions exercised by water and a fused nonmetallic oxide. Just as water dissolves an electrolyte at the price of having its structure disturbed, so also the reaction resulting from the addition of a metallic oxide to a fused nonmetallic oxide like silica is equivalent to a bond mpture between the Si04 tetrahedra (Fig. 5.70). Solvent action occurs in fused oxide systems along with a certain breakdown of the network structures present in the pure liquid solvent (e.g., in pure liquid silica). 

It Is effective for the removal of grelge mill oil, dirt, ollstalns, waxes, graphite, etc. In any scouring process where a combination of detergent and solvent action Is necessary. The use of this product allows the processor to work with detergents and solvents In the water phase without fire hazards. 

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