in water neutralization of crude H3PO4 with Na2CO3 at 35 or 70°C in presence of BaCO3, FeSO4 and activated coal;; product-mixture, diphosphate:monophosphate=1.67:1 at 70 °C without preceding filtration, ratio 1.05:1 at 35 °C;;
in water pptn. of glauberite at temperatures >65.6°C;;
参考文献
Gmelin Handbook: Na: SVol.1, 88, page 341 - 344
Full Text Show Details
General Chemical Co.
Patent: US1747588 , 1930 ;
C. I, 1930 , p. 2613
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反应条件
in neat (no solvent) byproducts: SO2; react. of 1 mol red P with up to 5 mol Na2SO4 in presence of H3PO4 at 300-335°C until development of SO2 ceases;; mixture obtained;;
in water byproducts: CaSO4*2H2O; addn. of Na2SO4 to a soln. containing H3PO4 and Ca(H2PO4)2 (ratio=80:20 to 75:25), pptn. of CaSO4, addn. of NaOH to the filtrate until pH of 4.4has been achieved, crystn. of NaH2PO4;;
