Solubility tetraborates

Description of Method. The water-soluble vitamins Bi (thiamine hydrochloride), B2 (riboflavin), B3 (niacinamide), and Be (pyridoxine hydrochloride) may be determined by CZE using a pH 9 sodium tetraborate/sodlum dIhydrogen phosphate buffer or by MEKC using the same buffer with the addition of sodium dodecyl-sulfate. Detection Is by UV absorption at 200 nm. An Internal standard of o-ethoxybenzamide Is used to standardize the method. 

Diammonium Tetraborate Tetrahydrate. Diammonium tetraborate tetrahydrate, (NH 2 4Dy 4H2O or (NH 2D 2B202 H2O formula wt, 263.37 monoclinic sp gr, 1.58 is readily soluble ia water (Table 9). The pH of solutions of diammonium tetraborate tetrahydrate is 8.8 and iadependent of concentration. The compound is quite unstable and exhibits an appreciable vapor pressure of ammonia. Phase relationships have been outlined and the x-ray crystal stmcture formula is (NH 2P4D5(OH)J 2H20 (124). 

Dipotassium Tetraborate Tetrahydrate. Dipotassium tetraborate tetrahydrate, IC,B4Oy 4H20 or K O 2B2C>3 4H20, formula wt, 305.49 orthorhombic sp gr, 1.919 is much more soluble than borax in water. Solubility data are given in Table 9 pH with concentration is given in Table 10. 

Sodium nitrate III Sodium nitrite VIII Sodium peroxide IV, Q. 61 Sodium sulphate Q. 3, II Sodium tetraborate Q. 23 Starch, soluble IV, VII, VIII Strontium carbonate P. 21 Sugar, cane III, VIII Sulphur, flowers II, IV, VIII Tartaric Acid III... 

Nickel Borates.—Several borates of nickel have been described. The tetraborate, NiO.4B2O3.10H2O, is obtained 2 by slow evaporation of a solution of nickel carbonate in boric acid. The precipitate first formed becomes crystalline gradually, yielding small brilliant and clear green crystals soluble in cold water, but becoming turbid at 40° C. 

Sodium tetraborate (Borax), Na2B407.10H2O. The anhydrous (fused) sodium tetraborate, Na2B407, is even more suitable for the borax bead tests Sodium thiosulphate, Na2S203.5H20 Starch (potato-starch or soluble starch)... 

Ammonium borates.—Many borates of ammonium have been described, hut their existence as definite chemical individuals is in most instances doubtful.18 Ammonium tetraborate, (NH4)2B407,4H20, is prepared by cooling a warm solution of boric acid in excess of ammonium hydroxide. It forms tetragonal crystals,19 soluble in 12 times their weight of water at the ordinary temperature. 

The tliird hydrate of sodium tetraborate, kemite, Na2B407 4Hs0, is more soluble than the other phases. 

Borates are the most commonly used and versatile of the unfixed waterborne preservatives. They include formulations prepared from sodium tetraborate, sodium pentaborate and boric acid but the most common form is disodium octaborate tetrahydrate (DOT). DOT has higher water solubility than other forms of borate. Glycol is also used to increase solubility in some formulations. 

Sodium tetraborate (Spectroflux 200 , Johnson and Matthey Co.) was tried with much greater success. Disks produced by fusion of 0.5000 g of calcined gypsum and 6.00 g of sodium tetraborate (Table 1) produced absolutely clear and transparent disks with perfect surfaces. The use of a higher specimen to flux ratio was dictated by the lower solubility of anhydrite in molten borax. 

Sirius , autotitration equipment, 11,18 Sodium tetraborate (borax) solutions, 16 Solubility-pH dependence method, 10-15, 18-19,22... 

Sodium Borates (11). These water-soluble salts, made by U.S. Borax and others, have been known since the eighteenth century as nondvu-able flame retardants for cotton, rope, canvas, and paper. The hydrated salts can act as endothermic heat sinks and moreover the salt fuses to a nonflammable glassy barrier layer. Sodium borates, in particular borax (sodium tetraborate decahydrate [1303-96-4]), are used in disposable paper and nonwoven cellulosic products, and as wood flame retardants where their water solubility can be tolerated. The borate salts are effective on flaming combustion but allow severe afterglow they are best used in formulations with afterglow preventatives, and often used with boric acid. 

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