Aqueous ammonium citrate

The resulting salt, whilst readily soluble in dilute mineral acids, is insoluble in cold acetic acid, phosphoric acid, and sodium phosphate. It is slightly soluble in citric and tartaric acid solutions, and readily dissolves m neutral aqueous ammonium citrate, yielding a green solution with a brownish tint.3 The salt is insoluble in water, but hot water hydrolyses it, and boiling with excess of ammonia solution converts it into a mixture of ferric hydroxide 4 and ferric phosphate, or if the ammonia is present in great excess the ferric phosphate may be entirely decomposed. Thus —... 

Adhesion performance was evaluated by accelerated aging of torsion joints in water at 57°C. Surface treatment involves preactivation of the steel surface with aqueous ammonium citrate solution and treatment with the mercaptoester in organic solution. 

Test B - Treated with a 3% aqueous ammonium citrate (pH 7.0 solution. Subsequent treatment with HTTHG in methanol for 15 minutes. 

Test A - Treated with 3% aqueous ammonium citrate solution aged for one week in air. Test B - Treated with 3% aqueous ammonium citrate solution made just prior to use. 

Available potash is considered to be that which is soluble in water, aqueous ammonium oxalate, or aqueous ammonium citrate. 

For aluminum, two cases were found. When anodization was carried out in a solution of 50 g/liter sodium tetraborate in 95 % ethylene glycol-5 % water, was found to be 0.58 + 0.04. However when the aluminum was anodized in aqueous ammonium citrate, varied substantially with current density from about 0.37 to 0.1 mA/cm to 0.72 at lOmA/cm. The experimental error in each value was about 10%, but an error in calculation of the total oxide thickness would have meant that the high current-density value would have been nearer to that obtained in the ethylene glycol solution. 

Figure 8.15 Effect on the durability of epoxy/carbon steel joints of a pretreatment based upon preactivation of the substrate with aqueous ammonium citrate followed by application of hexanetriol trithioglycolate as a primer [71].

According to a Macherey-Nagel application note [35], a mixture of 20 ng each of (i)-cysteine, (L)-glutathione, and (L)-penicillamine was resolved in less than 12 min by HPLC. The method used a Nucleosil 100-5SA column (15 cm x 4.6 mm i.d.) with aqueous 4.5 g/L ammonium citrate-6 g/L phosphoric acid at pH 2.2 as the mobile phase (eluted at 1 mL/min) and electrochemical detection at a gold electrode polarized at +800 mV. 

Iron(III) citrate, " " or iron(III) ammonium citrate, is the usual vehicle for administering supplementary iron to an iron-deficient patient, for inducing iron-overload in rats or other creatures prior to testing the efficacy of iron chelators, or for introducing the isotope Fe for metabolic tracer studies. Stability constants for the aqueous iron(III)-citrate system have been established. " The 2 1 complex is claimed to be the dominant species in iron(III)/citrate/DMF systems. " There has been a very qualitative study of the incorporation of iron into transferrin from iron citrate. " Iron(III) citrate reacts relatively slowly with the aluminum(III)-transferrin complex to give the thermodynamically strongly favored combination of iron(III)-transferrin with aluminum(lll) citrate. " The mechanism of iron uptake from citrate complexes in cells has been briefly discussed. An octa-iron citrate complex appears in Section 5.4.5.4.3 below. 

Ferric Ammonium Citrate, Brown, occurs as thin, transparent brown, red-brown, or garnet red scales or granules, or as a brown-yellow powder. It is a complex salt of undetermined structure, composed of iron, ammonia, and citric acid. It is very soluble in water, but is insoluble in alcohol. The pH of a 1 20 aqueous solution is about 5.0 to 8.0. It is deliquescent in air and is affected by light. 

L. Dimethyl ammonium citrate (DAC) solution is prepared by dissolving 192.6 g of citric acid in 1 L of warm water. The solution is cooled and brought to 2 L by adding 891 mL of aqueous dimethyl ammonium solution (33 percent). A 5- to 10-second application of DAC on a polished surface structurally etches alite strongly and belite slightly. An optional preparatory etch with water for five seconds will aid in the identification of aluminate. 

InP(lll) substrates by anodic, chemical, and thermal oxidation was studied [55]. The anodization was carried out in an aqueous solution of ammonium citrate and propylene glycol at an applied potential of 120 V. Concentrated nitric acid was used for the chemical oxidation at 80°C for 15 min, and the thermal oxidation occurred in a flow of wet oxygen, Tq = 450°C, ThjO = 95°C. The oxide thickness was 80-150 nm. The effect of a thermally deposited metallic coating (Au or Al, d = 0.2-0.3 xm) on the oxide chemical composition was studied by IRRAS. Conditions of optimum and degraded electrophysical characteristics of the MOS structures were achieved by annealing at 300 and 530°C, respectively, for 1 h in a mixture of N2 and O2. 

FIGURE 15.21 Drying of different iron salts applied by spin-coating on silicon wafers, the surface of which is hydrophiUc due to treatment with an aqueous H2O2-NH solution. Top left iron(II) ammonium sulfate top right ironflll) chloride. Bottom left iron nitrate bottom right iron ammonium citrate. 

The limitations of ion exchange materials for lanthanide separations based on the aquo cations led to the development of separation procedures mediated by aqueous complexants. The first such separations used ammonium citrate as the eluant. The displacement of from the resin by and NHJ is greatly augmented by the formation of lanthanide-citrate complexes, which tend to enhance transfer of the lanthanide ions to the mobile phase. The relative rates of movement of the rare-earth cations down the column is thus impacted not only by the affinity of the resin phase for the cations, but also by the relative stability of the aqueous citrate complexes. This approach forms the basis of the most useful and successful chromatographic separations of the lanthanides. 

For Bi, B2, B3, and Bg, a ground sample (1 g) was autoclaved with HCl (120° C, 30 min), cooled, diluted to known volume with aqueous ammonium acetate, vortexed, and centrifuged. The filtered supernatant was injected onto the LC column. For B5, a ground sample (4 g), was treated with acetate buffer (pH = 5.6) and autoclaved (121° C, 15 min), cooled, diluted to known volume with aqueous ammonium formate, vortexed, and centrifuged. The filtered supernatant was injected onto the LC column. For B9, ground sample (2.5 g) was mixed with a sodium phosphate—sodium citrate/ ascorbate buffer (pH = 8), heated, cooled, and incubated with papain and di-a-amylase (40°C, 2 hr). The solution was diluted to known volume with aqueous ammonium formate, vortexed, and centrifuged. 

An aqueous precursorfor 0.75Pb(Zni/3- Nb2/3)O3-0.25BaTiOs solid solution was synthesized by Van Werde et al. (2001). They used acetates of lead and zinc, and Nb(V) peroxocitrato complex. The solution of lead zincate niobate was prepared by adding the compounds into aqueous solution of ammonium citrate. The aqueous solution was stable when pH was higher than 8 and the citrate acid/cation mole ratio was higher than 1.5. The aqueous precursor for barium titanate was prepared by using titanium(IV) peroxocitrato complex and barium acetate. They found that the solid solution of PZN and BT is crystallized as a perovskite phase at temperatures as low as 800°C. 

Table 5.14 Densities of aqueous solutions of lithium, sodium, potassium and ammonium citrates as a function of temperature and concentration. A and B coefficients of Eq. (5.38)...

Han J, Pan R, Xie X, Wang Y, Yan Y, Yin G, Guan G (2010) Liquid-liquid equilibria of ionic liquid l-butyl-3-methylimidazolium Xetrafluoroborate + sodium and ammonium citrate aqueous two-phase systems at (298 15, 308 15, and 323 15) K. J Chem Eng Data 55 3749-3754... 

Li YL, Zhang MS, Su H, Liu Q, Guan WS (2013) Liquid-liquid equilibria of aqueous two-phase systems of the ionic liquid brominatedN-ethyl pyridine and sodium dihydrogen phosphate, sodium sulfate, ammonium citrate, and potassium tartrate at different temperatures experimental determination and correlation. Fluid Phase Equil 341 70-78... 

OC-Hydroxycarboxylic Acid Complexes. Water-soluble titanium lactate complexes can be prepared by reactions of an aqueous solution of a titanium salt, such as TiCl, titanyl sulfate, or titanyl nitrate, with calcium, strontium, or barium lactate. The insoluble metal sulfate is filtered off and the filtrate neutralized using an alkaline metal hydroxide or carbonate, ammonium hydroxide, amine, or alkanolamine (78,79). Similar solutions of titanium lactate, malate, tartrate, and citrate can be produced by hydrolyzation of titanium salts, such as TiCl, in strongly (>pH 10) alkaline water isolation of the... 

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