Inorganic precipitates whitings

Oceanic surface water is everywhere supersaturated with respect to the two solid calcium carbonate species calcite and aragonite. Nevertheless, carbonate precipitation is exclusively controlled by biological processes, specifically the formation of hard parts (i.e. shells, skeletal parts, etc.). The very few existing accounts of spontaneous inorganic precipitation of CaCOj(s) (so-called "whitings") come from the Bahamas region of the Caribbean (Morse et al., 1984). 

Inorganic arsenates are found to be extremely toxic in nature and hence careful control is maintained by the addition of magnesium ammonio-sulphate solution to an aqueous solution of the sample, thereby producing an instant white precipitate. 

Hexacyanoferric(II) acid, ferrocyanic acid or tetrahydrogen hexakis(cyanate-(4-)) [17126-47-5] is used to prepare many adducts with oxygen-containing organics. Also addition compounds with inorganic salts are known. This acid may be obtained as a white precipitate upon addition of potassium ferrocyanide to concentrated hydrochloric acid ... 

The inorganic acid used for the preparation of white carbon black can be any of the hydrochloric, sulfuric or nitric acids that mostly used is sulfuric acid and it is also used in the present investigation as the reagent or the precipitant. 

To 1 M KOH solution (15 mL) was added 3-(aroylamino)phthalimide (0.005 mol). The mixture was wamied to 50 °C with stirring and maintained at this temperature for 30 min after complete solution had been achieved. The mixture was allowed to cool to rt and acidifred with 1 M HCI. The resulting white precipitate was removed by suction filtration, washed several times on the filter with cold H O to remove inorganic impurities, and air-dried. The crude product was recrystallized from EtOH. 

It may be purified by solution in alcohol and precipitation with acetone. The substance is a white, very hygroscopic powder, which melts with decomposition and evolution of gas at 116° to 117° C. (corr.). It is soluble in water or alcohol, but insoluble in ether. Its aqueous solutions decompose on standing for a week, yielding a white precipitate and inorganic mercury in solution. 

Properties Rose-colored crystals, almost white when precipitated. D 3.125, mp (decomposes). Soluble in dilute inorganic acids almost insoluble in common organic acids both concentrated and dilute, insoluble in water. 

To a solution of 2,6-di-/m-butyl-4-methylphenol (13.22 g, 60 mmol) in degassed hexane (40 mL) was added a 2 M hexane solution of Me Al (15 mL, 30 mmol) at room temperature. A white precipitate appeared immediately. After 1 h, this mixture was heated until the precipitate redissolved in hexane. The resulting solution was allowed to stand for 3 h, yielding colorless crystals which were filtered in an argon box. Since the crystals contain some impurities such as 2.6-di-/c/7-butyl-4- methylphenol and inorganic aluminum salts, they were further recrystallized from hexane (45 mL) at -20 °C to give essentially pure methylaluminum bis(2.6-di-/c/7-butyl-4-methylphenoxide) (MAD) (7.83 g, 54% yield). 

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