Yield precipitation

Large amounts of chloride, cobalt(II), and chromium(III) do not interfere iron(III), nickel, molybdenum)VI), tungsten(VI), and uranium(VI) are innocuous nitrate, sulphate, and perchlorate ions are harmless. Large quantities of magnesium, cadmium, and aluminium yield precipitates which may co-precipitate manganese and should therefore be absent. Vanadium causes difficulties only... 

One type of chemical approach to the analysis of liquid and solid hydrocarbons that will probably see considerable development is that involving reaction or complex formation to yield precipitates that can be separated from the unreacted mass and subsequently be treated to regenerate the hydrocarbons or class of hydrocarbons so precipitated. This field is certainly not extensively developed. In fact very few examples come to mind but among these are Gair s (21) determination of naphthalene by precipitation with picric acid determination of benzene by Pritzker and Jungkunz (52) by an aqueous solution of specially prepared nickel ammonium cyanide Bond s (8) nitrous acid method for styrene and more recently the determination of normal alkanes in hydrocarbons of more than 15 carbon atoms by adduct formation with urea as described by Zimmerschied et al. (71). 

Basic sulphates are obtained when the normal sulphates of antimony, bismuth and mercury are treated with water, sulphuric acid being produced simultaneously. These salts are insoluble in water. Many other metals, for example copper,6 aluminium 8 and tin,7 yield precipitates of basic sulphates on the addition of alkali to aqueous solutions of their normal sulphates. 

The detection of niobium and tantaluA ideg nfli almost entirely on the reactions given by niobic acid and tanxanc acid. All the common niobium and tantalum compounds are hydrolysed on bdng boiled in acid solutions, and yield precipitates of the respective adds. Natural minerals are previously fused with potassium hydrogen sulphate, and the aqueous extract of the melt usually precipitates the mixed acids... 

Sulphides.—Definite sulphides of niobium have not been prepared. Solutions of alkali niobates do not yield precipitates with hydrogen... 

Sodium hydrosulphite reduces arsenates and arsenites, yielding precipitates containing sulphides the composition of which varies with conditions. In strongly acid solutions arsenic trisulphide is the main product.2 Sodium thiosulphate also precipitates arsenic as the trisulphide from acid solutions,3 but the amount of precipitation depends on the nature and concentration of the acid present. Thus, with hydrochloric, perchloric or sulphuric acid, the precipitation reaches a maximum of 50 to 80 per cent, for 0-1N acid,4 and above this concentration the amount of precipitation falls to zero with hydrochloric acid but passes through a minimum with perchloric acid at N concentration and with sulphuric acid at 2 to 3N concentration. At still higher acid concentrations precipitation becomes almost quantitative. 

Substance (soluble in water) yields precipitate—salt of alkaloid. 

C. Kubierschky 6 prepared a series of oxythiophosphates with only part of the oxygen of the normal phosphates replaced by sulphur. He said that acids decompose all thiophosphates hydrogen sulphide is evolved, and, in some cases, sulphur separates. Monothiophosphates give white precipitates with calcium, barium, and strontium salts, the dithiophosphates with barium and strontium salts, and the trithiophosphates with barium salts only. All thiophosphates yield precipitates with cadmium, copper, silver, and mercurous salts, which decompose after a time,... 

The configurations of the cis and trans forms of dinitro-bis(ethylenediamine)cobalt(III) ion were established by Werner,4 who resolved the cis form into its optical antipodes. The cis and trans isomers may also be distinguished chemically by utilization of the fact that a warm aqueous 3 % solution of the cis form yields precipitates when treated with concentrated solutions of potassium chromate, ammonium oxalate, or sodium thiosulfate a warm 10% solution of the trans form gives no precipitate with any of these reagents.3... 

Silicon Dioxide occurs as an amorphous substance that shows a noncrystalline pattern when examined by X-ray diffraction. It is produced synthetically, either by a vapor-phase hydrolysis process, yielding fumed silica, or by a wet process, yielding precipitated silica, silica gel, colloidal silica, or hydrous silica. Fumed silica is produced in an essentially anhydrous state, whereas the wet-process products are obtained as hydrates or contain surface-adsorbed water. 

Uranyl Carbonate occurs in a fairly pure condition in the mineral rutherfordine (see p. 273). It has not been obtained artificially. The addition of an alkali carbonate to solutions of uranyl salts yields precipitates of var nng conqiosition consisting of basic carbonates sometimes mixed vnth uranate. ... 

Beaton s failure to prepare ReFg AsFg by precipitation from WFg solution has been confirmed by the present studies and SO2CIF solutions of ReF have not yielded precipitates with AsFj, even at 213 K. This stands in marked contrast with the high thermal stability [7] of IFg AsFg . Unfortunately the... 

A solution containing 22 grams of y>aminophenylarsenoxidc and 18 15 grams of arsenic trichloride in 100 c.c. of methyl alcohol is slowly added to a well-coolestannous chloride in 200 c.c. of hydrochloric acid (density 1 19) and 200 c.c. of methyl alcohol. The product is brownish-yellow and cont ns 45 per cent, of arsenic. It is soluble in hot dilute hydrochloric acid and in moist pyridine, the acid solution yielding precipitates with dilute sulphuric acid and excess of sodium hydroxide. 

The author stated that the only substances which yielded precipitates with the reagent were terj enes, and acetone or acetyl acetone on warming. 

N-Alkylbetaines, RN+(CH3)2CH2COO These materials are zwitterionic at pHs at and above their isoelectric points (neutral and alkaline pHs) and cationic below their isoelectric points (acid pHs). They show no anionic properties. Compatible with all classes of surfactants at all pHs, except that at low pHs they yield precipitates with anionics. Acid and neutral aqueous solutions are compatible with alkaline earth and other metallic ions (Al3+, Cr3+, Cu2+, Ni2+, Zn2+). They... 

Figure 1 shows the effect of substrate concentration on %-yield precipitated product for 20 min reactions under non-controlled pH conditions (phosphate buffer 0.9 M). At initial pH 7, the %-yield increased from 56 3 to 71 4 % by increasing the substrate concentration from 0.03 to 0.3 M. The yield remained unchanged as the substrate concentration was increased from 0.3 to 0.5 M and then decreased to 58 3 % by increasing the substrate concentration to 0.7 M. A similar trend was observed when reactions were performed at initial pH 8, except, product yields were higher than those at pH 7 for substrate concentrations 0.03 to 0.5 M. The apparent maximum %-yields (71 4% and 81 4%) occurred at 0.3 M substrate concentration for reactions at pH 7 and 8, respectively. 

Identification of Aromatic Amines.—Most aromatic amines are soluble in hydrochloric acid, and are precipitated from the solution of their salts so formed by bases. Aqueous solutions of the amines, even when very dilute, yield precipitates of bromine substitution-products when treated with bromine water. The reaction is not characteristic, however, as phenols act in a similar way. 

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