Sodium forms occurring

The a-isomeride has m.p. 138°, yields a hydrochloride, m.p. 135° [approx., dec.), and a picrate, m.p. 198°. The 3-form occurs in minute needles, m.p. 108-9° (dry), and yields a picrate, m.p. 178-9°. These substances are of interest since their methiodides and methochlorides on treatment with silver oxide or aqueous sodium hydroxide behave abnormally, breaking up into veratraldehyde and 4 5-dimethoxy-2-vinylbenzyldimethylamine (oil picrate, m.p. 158-9° methiodide, m.p. 197-8°) thus — ... 

Weakly acidic cation exchangers (e.g. polymethylacrylic acid resins). These resins (Zerolit 226, Amberlite 50, etc.) are usually supplied in the hydrogen form. They are readily changed into the sodium form by treatment with 1M sodium hydroxide an increase in volume of 80-100 per cent may be expected. The swelling is reversible and does not appear to cause any damage to the bead structure. Below a pH of about 3.5, the hydrogen form exists almost entirely in the little ionised carboxylic acid form. Exchange with metal ions will occur in solution only when these are associated in solution with anions of weak acids, i.e. pH values above about 4. 

The spiro compound 206 was prepared in five steps from (S)-l-naphthyl-ethylamine and was composed of a mixture of imine and enamine tautomers. Reduction of the imine function by sodium borohydride occurred on the less hindered si face, leading to the diamine with the R configuration of the newly formed stereo center, then the N-benzyl substituent was removed by hydrogenolysis to give 207 with good overall yield [98] (Scheme 30). 

Tophi Chalky deposits of sodium urate occurring in gout. Tophi form most often around joints in cartilage, bone, bursae, and subcutaneous tissue and in the external ear, producing a chronic, foreign-body inflammatory response. If untreated, tophi can lead to joint deformity or destruction. 

Some recent interest in the technetium chemistry has been focused on complexes possessing a Tc=N3+ core. Tetrachloronitridotechnetate(VI) complexes can easily be synthesized by the reaction of pertechnetate with sodium azide in concentrated hydrochloric acid [34], Although its square-pyramidal structure resembles that of tetrachlorooxotechnetate(V) complexes, stable character of the nitrido complexes in aqueous solution shows a remarkable contrast to the oxo complexes. However, when a strong acid and a coordinating ligand are absent, the interconversion of di(p-oxo)nitridotechnetium(VI) complexes to the monomeric form occurs in the following complicated manner [35]... 

Naming of the positive ion depends on whether the cation is monatomic (has one atom). If not, the special names given in Sec. 6.3.2 are used. If the cation is monatomic, the name depends on whether the element forms more than one positive ion in its compounds. For example, sodium forms only one positive ion in all its compounds—NaT Iron forms two positive ions—Fc2r and Fe,+. Cations of elements that form only one type of ion in all their compounds need not be further identified in the name. Thus, Na may simply be called the sodium ion. Cations of metals that occur with two or more different charges must be further identified. Fe(NO,)2 and Fe(NO,)3 occur with Fc2+ and Fe3 ions, respectively. If we just call the ion the iron ion, we will not know which one it is. Therefore, for monatomic cations, we use a Roman numeral in parentheses attached to the name to tell the charge on such ion. (Actually, oxidation numbers are used for this purpose, but if you have... 

Sodium carbonate occurs in nature as monohydrate in the mineral ther-monatrite. It also occurs naturally as the mineral natron or natrite in its decahydrate form. 

Sodium sulfate occurs in nature as the minerals mirabilite and thenardite. While thenardite is the anhydrous form of Na2S04, mirabilite is a naturally-occurring decahydrate, Na2S04 IOH2O. 

A comparative study of the products of dehydration of the dihydrogen monophosphates of polyvalent cations showed that the stable end-products for cations with ionic radii between 0.57 and 1.03 A. (Cu++, Mg++, Ni++, Co++, Fe++, Mn++, Zn"1-1", Cd++, A1+++) are tetrametaphosphates. When the cations are either larger or smaller the end-products of dehydration are crystalline high-molecular polyphosphates (Li+, Be++, K+, Rb+, Cs+, Ag+, Zn++, Cd++, Hg++, Ca++, Sr++, Ba++ Pb++, Cr+++, Fe+++, Bi+++). In the case of the alkali salts only sodium trimetaphosphate occurs as a condensed phosphate with a cyclic anion (304, 305). Up to the present, an alkali tctrametaphosphate has not been observed as the dehydration product of a dihydrogen monophosphate. Consequently, alkali tetrametaphosphates arc obtainable only indirectly. Reference is made later (Section IV,C,4) to the fact that the tetraphosphates of barium, lead, and bismuth are formed as crystalline phases from melts of the corresponding composition. There are also reports of various forms of several condensed phosphates of tervalent iron and aluminum (31, 242, 369). 

The properties of the alkali metals and of their salts are roughly functions of the at. wt. of the metals. There is generally a break in the curve about potassium so that lithium and sodium form one series, and potassium, rubidium, and caesium another. The properties of the series, K, Rb, Cs generally change more regularly than the series Li, Na, K, although some irregularities do occur—e.g. the m.p. of the nitrates. 

Sodium fluoride occurs in combination with some minerals—e.g. cryolite—and the fluorine in many natural waters is probably combined as sodium fluoride. All the five alkali metals form normal fluorides of the type RE and acid fluorides RF.HF, or still higher acid fluorides RF.wHF are known. 

When the reaction between aminoguanidine and sodium nitrite occurs in the presence of an excess of acetic acid, still another product is formed, namely, 1,3-ditetrazolyltriazine, the genesis of which is easily understood from a consideration of the reactions already mentioned. 5-Aminotetrazole is evidently formed first the amino group of one molecule of this substance is diazo-tized by the action of the nitrous acid, and the resulting dia-zonium salt in the acetic acid solution couples with a second molecule of the aminotetrazole. 

Amination of chloromethylsilanes with sodium azide occurs readily in an aprotic solvent (DMF or HMPA93). The new azides formed afford the corresponding primary amines in excellent yield after treatment with LAH or PPh3.88,94... 

The pyridinium salts have been shown to have electrophilic positions at the 2-, 4-, and 6-carbon atoms. Of these, the 2- and 6-positions should be the more positive because of the proximity to the quaternary nitrogen. From the ultraviolet absorption spectra of the reaction mixtures during the reduction and of the isolated products, it can be demonstrated that the predominant attack of the hydride ion from sodium borohydride occurs at these two positions.5,6 The 1,6-dihydro-pyridine (such as 5) formed from the reduction of a 1,3-disubstituted pyridinium ion appears to be stable toward further reduction, for a number of such compounds have been isolated from sodium borohydride reductions containing sufficient borohydride to complete the reduction to the tetrahydro-state.7"10 Since 1,4-dihydropyridines having a 3-substituent which is electron-withdrawing have also been... 

Many naturally occurring ionic polysaccharides are mixed salts of alkali, alkali-earth, and transition metals with different insolubilities. Salts of alkali metals are invariably soluble. Sodium, the most ubiquitous alkali, possesses a single valence electron, large atomic and ionic radii, and very low ionization potential. Na+ hydrates in aqueous solution and retains its coordination water in the solid state. Prior to use, native polysaccharide salts are usually converted to the sodium form whence they acquire functionality. 

Sodium Acetate occurs as colorless, transparent crystals or as a granular, crystalline or white powder. The anhydrous form is hygroscopic the trihydrate effloresces in warm, dry air. One gram of the anhydrous form dissolves in about 2 mL of water 1 g of the trihydrate dissolves in about 0.8 mL of water and in about 19 mL of alcohol. 

Sodium Hydroxide occurs as white or nearly white pellets, flakes, sticks, fused masses, or other forms. Upon exposure to air it readily absorbs carbon dioxide and moisture. One gram dissolves in 1 mL of water. It is freely soluble in alcohol. 

Sodium Phosphate, Monobasic, is anhydrous or contains one or two molecules of water of hydration and is slightly hygroscopic. The anhydrous form occurs as a white, crystalline powder or granules. The hydrated forms occur as white or transparent crystals or granules. All forms are freely soluble in water, but are insoluble in alcohol. The pH of a 1 100 solution is between 4.1 and 4.7. 

Sodium Saccharin occurs as white crystals or as a white, crystalline powder. In powdered form, it effloresces to the extent that it usually contains only about one-third the amount of water indicated in its molecular formula. One gram is soluble in 1.5 mL of water and in about 50 mL of alcohol. 

Reductions of carbonyl groups with lithium aluminium hydride or sodium borohydride occur by hydride transfer to carbon from aluminium or boron, respectively. The course of reaction is subject to steric approach control and product development control [43-45]. Enzymic reactions may or may not form the epimer favoured in the chemical reduction. This has been discussed elsewhere [46]. It is quite clear that the steric course of a dehydrogenase reaction is determined by the structure of the enzyme. 

For calcium zeolites, x-ray diffraction and infrared studies together have shown that the first 16 or 18 calcium ions introduced into the unit cell of the sodium form are located in the hexagonal prisms and sodalite portions of the structure 1, 2, 23). Addition of further calcium ions results in the occupation of sites in the supercages. The changes in intensity of the hydroxyl infrared bands and the onset of the cation-pyridine interactions indicate that the same preferential location of calcium ions in calcium hydrogen Y zeolite occurs (23). 

Mordenite is a naturally-occurring silica-rich zeolite (Si/Al 5) which also can be synthesized readily (34). Meier determined the structure of its fully hydrated sodium form (28). The mordenite framework is characterized by a micropore system composed essentially of parallel elliptical cylinders of maximum and minimum crystallographic free diameters of 7.0 and 5.7A, respectively, these main channels being interconnected by smaller side channels. 

---