Other

28.35 - Phosphinates (h o hosphites), phos honates (phosphites) and phosphates; polyphosphates, wy RetRer or not chemic y defined. d 2835.10 2835.22 2835.24 2835.25 2835.26 2835.29 2835.3 1 2835.39 - Phosphinates (hypophosphites) and phosphonates (phosphites) - Phosphates : - - Of mono- or disodiurn - - Of potassium - - Calcium hydrogenorthophosphate (" dicalcium phosphate ") - - Other phosphates of calcium - - Other - Polyphosphates : - - Sodium triphosphate (sodium tripolyphosphate) - - Other (A) PHOSPHINATES (HYPOPHOSPHITES) Subject to the exclusions mentioned in the introduction to this sub-chapter, this headin includes hos hinates (hypophosphites), metal salts of phosphinic (hypophosphorous) aci (HP02)(Readkg 28.1 1). f These are soluble in water and decompose on heating with evolution of hydrogen phosphide which ignites spontaneously. Alkali phosphinates are reducing agents. The most important are : (I) Sodium phosphinate (hypophosphite) (NaPH202),in white tablets or crystalline powder, hygroscopic. (II) Calcium hosphinate (hypophos hite) (Ca(PH202)2),colourless crystals or a white t' powder (o tained by the action of w ite phosphorus on boiling milk of lime). Both these products are used in medicine as tonics or restoratives. (111) Ammonium, iron or lead phosphinates (hypophosphites). (B) PHOSPHONATES (PHOSPHITES) Subject to the exclusions mentioned in the introduction to this sub-chapter, this headin includes phos honates ( hosphites), metal salts (neutral or acid) of phosphonic acid (H3P03)beading 2 -11). 6' The most important phosphonates are those of ammonium, sodium, potassium or calcium, soluble in water and acting as reducing agents. (C)PHOSPHATES AND POLYPHOSPHATES Subject to the exclusions mentioned in the introduction to this sub-chapter, this heading includes metal phosphates and polyphosphates derived from the acids of heahng 28.09, i.e. : (I) Phosphates - metal salts of phosphoric acid (H3PO4).These are the most often called " phosphates " without further qualification. The salts acid with monovalent metals may be mono-, di- or tribasic (with contain one, two or three metal atoms); there are, for example, three sodium phosphates : sodium dihydrogenortho hosphate (monobasic phos hate (NaH2P04)), disodium h~drogenorthohosphate rdibasic phosphate (Na2HPo4)T and trisodiumorthophosphate (tribasic phosp ate (Na3P04)). I?, (U) Pyrophosphates (diphosphates) - metal salts of pyrophosphoric acid (&P2O7). (III) Metaphosphates - metal salts of metaphosphoric acids (HPO&. (IV)Other polyphosphates - metal salts of polyphosphoric acids having a high degree of polyrnerisation. The most important phosphates and polyphosphates are : (1) Ammonium phosphates and polyphosphates. (a) Triammonium orthophosphate ((NH&PO4), stable in aqueous solution only. (b) Ammonium polyphosphates. There are several ammonium polyphosphates having a degree of polymerisation ranging from a few units to a few thousand. They occur as white crystalline powders, soluble or insoluble in water; the are used in the preparation of fertilisers, in fire-proofing additives for varnish or in re-proofing preparations. F They remain in this heading even though their degree of polymerisation is not defined. Ammonium dihydro enorthophosphate (monoammonium phosphate) and diammonium hydrogenortho- pho$ate d~ammoniurnphosphate), whether or not pun, and intermixtures thereof, are excluded £tom s heading (heading 31.05). (2) Sodium phosphates and polyphosphates. (a) Sodium dihydrogenorthophosphate (monobasic hosphate) (NaH2P04.2H20). Colourless crystals, soluble in water, which under e action of heat lose water (pulveesed phosphate) to become pyro hosphate and, finally, metaphosphate. Used in me&cine, in the man-made textiles inc?ustry, as a coagulant of protein substances, in electroplating, etc. & I (b) Disodium hydrogenorthophosphate (dibasic phos hate (Na2HP04), anhydrous white powder) or c stallised (with 2, 7 or 12 B20); olub e in water. Used as a size or silk (with tin c loride), for fire-proofing fabncs, wood or pa er, as a textile mordant, in chrome-tanning, in the manufacture of o tical glass, for g azing porcelain, aration of balun powder, in the man acme of colouring matters and in the soldering uxes, in electro-p ating, in medicine, etc. b B K preR k J P (c) Trisodium orthophosphate (tribasic phosphate (Na3P04.12H20).Colourless crystals, soluble in water, releasing part of their water o crystallisation on warming. Used as a flux for dissolving metal oxldes, in hotograph as a detergent, for sofkning industrial water and descaling boilers, to clarig sugar an spirits, in tanning, in medicine, etc. !f f (d) Sodium pyro hos hates (sodium diphosphates). Tetrasodium yrophosphate neutral diphosphate) fNa$2~7).Non-h groscopic white powder, solu73le in water. Ssed in laundering, in the preparation o detergents, of mixtures to prevent the coagulation of blood, of relligerating products and of disinfectants, in cheese manufacture, etc. H Disodium dihydrogenpyrophos hate (acid di hosphate) (NazH2PzO7),which has the same ap earance, is used as a fux in ename ing, for precipitating the casein from milk, an in the preparation of baking powder, of certain malted milk powders, etc. A B (e) Sodium triphos hate (Na5P30ro)(pentasodium triphosphate also known as sodium tripolyphosphatef:White crystalline powder; used as a water-softener, as an emulsifier or to preserve foodstuffs. ( f ) Sodium metaphosphates asic formula (NaP03),). Two metaphosphates meeting this description are sod~urncyc o-triphosphate and sodium cyclo-tetraphosphate. p Some sodium unspecified degree of These include : The product incorrectly known as sodium hexameta hosphate (a polymeric mixture of formula ((NaPO,)J, also known as Graham's salt. vlbeous substance or white powder, soluble in water. In aqueous solution, this product sequesters the calcium and the magnesium contained in the water, hence its use as a water-softener. Also used in the re aration of detergents and casein glues, to emulsify essential oils, in photography, n! $e manufacture of processed cheese, etc. (3) Potassium phosphates. The best known is potassium (mono otassium phosphate) (KH2P04). Obtained by orthop osphoric acid and potassium sulphate. Colourless a yeast nutrient and as a fertiliser. (4) Calcium phosphates. (a) Calcium hydrogenorthophosphate (" dicalcium phosphate " (CaHP04.2H20). Obtained by the action of an acidulated calcium chlonde so ution on disodium hydrogenorthophosphate. White powder, insoluble in water. Used as a fertiliser; as a mineral supplement to animal fodder, and in the manufacture of glass, medicaments, etc. ? Calcium hydrogenorthophosphate containing not less than 0.2 % by weight of fluorine calculated on the dry anhydrous product is excluded (heading 31.03 or 31.05). r, (b) Calcium tetrahydro enbis (orthophosphate) monocalcium phos hate) (CaH4 PO&. l or 2 ~ ~ 0Obtained 7. b treating bones wit sul huric acid or hy ogen chlori e. Occurs in thick solutions; re eases its water of crystalEsation under the ?chon of heat. It is the only calcium phosphate soluble in water. Used in the preparation of bahng powders, as a medicament, etc. 6: (c) Tricalcium bis(orthophos hate) (neutral calcium phosphate) (Ca3(P04)2). The heading covers precipltatJ calcium phosphate (i.e., ordinary calcium phosphate). Obtained by treatin the tricalcium phosphate contained in bones, first with hydrochloric acid anC f then with sodium hydroxide, or by precipitating a solution of trisodium orthophosphate by means of calcium chloride in presence of ammonia. Amorphous whte powder, odourless and insoluble in water. Used as a mordant in dyeing; to clari@ syru s; for pickling metals; in the manufacture of glass or ottery; in the preparation !o phosphorus and medicaments (e.g., lactopFIosphates, glycerophosphates), etc. Natural calcium phosphate is excluded (heading 25.10). Artificial aluminium orthophosphate (A1PO4), prepared fiom and aluminium sulphate, occurs as a white, greyish or pinkish ceramics, for sizing silk (with tin oxide), and in the preparation (5) of dental cements. Natural aluminium phosphate (wavellite) is excluded (heading 25.30). (6) Manganese phos hate (Mn3 P04)2.7H20). Obtained from rnanganous chloride and is a urp e owder which, alone or mixed with other products, phosphoric acid. constitutes Nuremberg vio et, use by artists and in enamels. Associated with ammonium phosphate, it forms Burgundy violet. 1: f 'B (7) Cobalt phosphates. Tricobalt bis (orthophosphateor) (Co3(P04)2.2 or 8 H20) is prepared fiom sodium orthophosphate and cobalt acetate. Amo hous ink powder, insoluble in water. When heated with aluminium oxide, gives T enard s blue used in enamels. Associated with aluminium phosphate, it is used in the preparation of cobalt purple. 1: (8) Other hosphates. These include phosphates of barium (opacifier), chromium (ceramic coloursf zinc (ceramic colours, dental cements, fermentation control, medicine), iron (medicine) and copper (ceramic colours). The heading also excludes certain phosphates, viz. : (a) Natural calcium phosphates, apatite and natural aluminium calcium phosphates (heading 25.10). (b) Other natural mineral phosphates of Chapter 25 or 26. (c) Ammonium dihydrogenorthophosphate monoammonium phosphate) and diammonium hydrogenorthophosphate (diammonium phosp ate), whether or not pure (heading 31.05). (d) Precious and semi-precious stones (heading 71.03 or 71.05).