Complexing agent acetic acid

Binary systems synthesized consisted of Cu/Fe, Ni/Fe, Cu/Al and Ni/Al and Cu/Cr for 4-10 wt percent Cu or Ni in the calcined mixed oxide. Anionic complexing agents acetic, citric and oxalic acids and EDTA were used in molar ratios of 1 1 with the initial copper or nickel. Two stage precipitations were used starting with an initial formation of aluminum, chromium or ferric hydroxide by addition of NaOH to an aqueous solution of A1 nitrate, Cr nitrate or Fe chloride. In the second stage aqueous solutions of Cu sulfate or Ni nitrate were mixed with the initial precipitate with or without the presence of a 1 1 mole ratio of selected anionic complexing agents to complete the precipitation. A second mode of coprecipitation used was to preadsorb oxalic acid on the initially precipitated AI, Cr or Fe hydroxide. 

Liquid-phase oxidation of lower hydrocarbons has for many years been an important route to acetic acid [64-19-7]. In the United States, butane has been the preferred feedstock, whereas ia Europe naphtha has been used. Formic acid is a coproduct of such processes. Between 0.05 and 0.25 tons of formic acid are produced for every ton of acetic acid. The reaction product is a highly complex mixture, and a number of distillation steps are required to isolate the products and to recycle the iatermediates. The purification of the formic acid requires the use of a2eotropiag agents (24). Siace the early 1980s hydrocarbon oxidation routes to acetic acid have decliaed somewhat ia importance owiag to the development of the rhodium-cataly2ed route from CO and methanol (see Acetic acid). 

Complexing agents, which act as buffers to help control the pH and maintain control over the free metal—salt ions available to the solution and hence the ion concentration, include citric acid, sodium citrate, and sodium acetate potassium tartrate ammonium chloride. Stabilizers, which act as catalytic inhibitors that retard the spontaneous decomposition of the bath, include fluoride compounds thiourea, sodium cyanide, and urea. Stabilizers are typically not present in amounts exceeding 10 ppm. The pH of the bath is adjusted. 

The dienone complex is an efiective phenylating agent for aromatic amines t.g., aniline and triearbonylcyclohexadienoneiron in glacial acetic acid at 75° overnight gives diphenylamine in 95% yield. ... 

Molecular bromine is believed to be the reactive brominating agent in uncatalyzed brominations. The brominations of benzene and toluene are first-order in both bromine and the aromatic substrate in trifluoroacetic acid solution, but the rate expressions become more complicated when these reactions take place in the presence of water. " The bromination of benzene in aqueous acetic acid exhibits a first-order dependence on bromine concentration when bromide ion is present. The observed rate is dependent on bromide ion concentration, decreasing with increasing bromide ion concentration. The detailed kinetics are consistent with a rate-determining formation of the n-complex when bromide ion concentration is low, but with a shift to reversible formation of the n-complex... 

Knabe has introduced mercuric acetate plus ethylenediaminetetraacetic acid (EDTA) as an oxidizing agent for tertiary amines (74). The solvent employed is 1 % aqueous acetic acid. In this system, the complexed mercuric ion is reduced to elemental mercury. Knabe s studies have centered on the... 

The formation of a single complex species rather than the stepwise production of such species will clearly simplify complexometric titrations and facilitate the detection of end points. Schwarzenbach2 realised that the acetate ion is able to form acetato complexes of low stability with nearly all polyvalent cations, and that if this property could be reinforced by the chelate effect, then much stronger complexes would be formed by most metal cations. He found that the aminopolycarboxylic acids are excellent complexing agents the most important of these is 1,2-diaminoethanetetra-aceticacid (ethylenediaminetetra-acetic acid). The formula (I) is preferred to (II), since it has been shown from measurements of the dissociation constants that two hydrogen atoms are probably held in the form of zwitterions. The values of pK are respectively pK, = 2.0, pK2 = 2.7,... 

In an earlier series of experiments, Cullis and Ladbury examined the kinetics of the permanganate oxidation of hydrocarbons in acetic acid solution. Initial attack on toluene occurs at the methyl group and a total order of two was found. Electron-withdrawing agents reduced the rate of oxidation. However, the effects of added salts were complex and the authors believe that lower oxidation states of manganese are responsible for the oxidation. The oxidation of ethylbenzene produced acetophenone, the process being second-order with... 

Precipitation of Fe(IIl) compounds from acid solutions as the pH increases above 2.2 is a particular problem. Complexing agents that have been used include 5-sulfosalicylic acid and citric acid (136) dihydroxymaleic acid (137) ethylenediaminetetraacetic acid (138) lactic acid (138) blends of hydroxylamine hydrochloride, citric acid, and glucono-delta-lactone (139) nitriloacetic acid blends of citric acid and acetic acid lactic acid and gluconic acid (140). 

Fig. 8 Nanosystems that may function as simultaneous drug delivery and imaging agents for targeting T cells (a) liposomal systems, (b) solid biodegradable nanoparticulates, and (c) macro-molecular dendrimer complexes. PEG polyethylene glycol, Gd-DTPA gadolininum-diethylene triamine penta acetic acid. (Adapted from [48])...

In the presence of complexing agents at a sufficiently high concentration it is possible to prevent the formation of the Pu(IV) polymer. Acetate at a concentration of 5 x 10 2m facilitated the retention of 90% of Pu(IV) as themonomerin concentrations of 10 sm Pu(IV) when the pH was raised from pH 2.8 to pH 5.7. However, citric acid and diethylenetriaminepentacetic acid (DTPA), both at 5 x 10 4m, were even more efficient at preventing polymer formation (14). 

Pertechnetate can also be reduced by p-thiocresol in acetic acid solution. With an excess of the reducing agent technetium forms a complex compound which readily dissolves in non-polar solvents such as chloroform, toluene or benzene. 

EDTA ethylene-diamine-tetra-acetic-acid (complexing agent)... 

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