Acetic acid addition

Acetic acid formulations frequently contain acetic acid additions as molecular weight regulators... 

Kinetic studies at 25 °C showed that for benzene, toluene, o-, m-, and p-xylene, /-butylbenzene, mesitylene, 4-chloroanisole, and p-anisic acid in 51 and 75 % aqueous acetic acid addition of small amounts of perchloric acid had only a slight effect on the reaction rate which followed equation (100). At higher concentrations of perchloric acid (up to 0.4 M) the rate rose linearly with acid concentration, and more rapidly thereafter so that the kinetic form in high acid concentration was... 

The anodic oxidation reaction of sulphoxides was not much studied, and just a few reports are available so far. The conversion into the corresponding sulphones of some phenyl alkyl and diaryl sulphoxides (oxidation potential for 86 + 2.07 V vs. SCE in acetonitrile/NaC104 electrolyte, Pt anode) has been reported. Similarly, diphenyl suiphoxide was long known to be transformed in a quantitative yield into the sulphone (Pt anode, solvent glacial acetic acid). Additional examples of the oxidation of a suiphoxide function attached to aryl groups are available . 

Lead tetraacetate is added in small quantities, with stirring, to an ice-cold suspension of 11 g. of ethyl 3-(D-arabino-tetrahydroxybutyl)-5-methyl 4-furoate in 100 ml. of benzene plus 40 ml. of glacial acetic acid. Addition is stopped when there is a positive reaction with potassium iodide-starch paper. The mixture is stirred for a further ten minutes, filtered, and the benzene solution washed twice with water. The benzene layer is then dried with anhydrous sodium sulfate, filtered, and the filtrate evaporated to dryness. The residue (6 g.) is mixed with a solution of 7.5 g. of sodium hydroxide plus 20 g. of silver nitrate in 40 ml. of water, and heated for 40 minutes on a steam bath. The aqueous solution is filtered, acidified to Congo Red while being cooled with ice, and the crystals formed are removed by filtration, washed with ice-cold water, and dried over phosphorus pentoxide in the vacuum desiccator yield, 2.2 g. After recrystallization from water, the product has m. p. 234r-235°. 

Copper-catalyzed monoaddition of hydrogen cyanide to conjugated alkenes proceeded very conveniently with 1,3-butadiene, but not with its methyl-substituted derivatives. The most efficient catalytic system consisted of cupric bromide associated to trichloroacetic acid, in acetonitrile at 79 °C. Under these conditions, 1,3-butadiene was converted mainly to (Z )-l-cyano-2-butene, in 68% yield. A few percents of (Z)-l-cyano-2-butene and 3-cyano-1-butene (3% and 4%, respectively) were also observed. Polymerization of the olefinic products was almost absent. The very high regioselectivity in favor of 1,4-addition of hydrogen cyanide contrasted markedly with the very low regioselectivity of acetic acid addition (vide supra). Methyl substituents on 1,3-butadiene decreased significantly the efficiency of the reaction. With isoprene and piperylene, the mononitrile yields were reduced... 

Also azide radicals generated by anodic oxidation of sodium azide in the presence of olefins afford in acetic acid additive dimers, products of allylic substitution and... 

Oxidation of A-acyltyramines 264 with IBTA proceeds with intramolecular participation of amido group oxygen in nonnucleophic solvents to give spiro-oxazines 265 (Scheme 66, route a ). In nucleophilic solvents such as alcohol or acetic acid, addition of solvent at the para position occurs to give quinone 266 (Scheme 66, route b ) (91JOC435). 

Removal of the p-methoxybenzyl group is accomplished by treatment with dichloro-dicyanoquinone (DDQ), which forms quantitatively aminal 17 in an 11.5 1 diastereomeric ratio (Yu and Levy, 1984). The solution is treated with sodium methoxide in methanol, which decomposes the aminal into the desired amine 18 and p-methoxybenzaldehyde. Due to the difficulties in separating the p-methoxybenzaldehyde from amino alcohol 18, the aldehyde is reduced in situ with sodium borohydride. The amino alcohol 18 is crystallized from the reaction mixture after neutralization with acetic acid. Additional recrystallization provides the desired amino alcohol 18 in 94% yield. 

Perchloric acid is the strongest of the common acids in acetic acid solution and the titration medium usually used for non-aqueous titration of bases is perchloric acid in acetic acid. Addition of acetic anhydride, which hydrolyses to acetic acid, is used to remove water from aqueous perchloric acid. Weak bases compete very effectively with acetic acid for protons. Oracet blue, quinalidine red and crystal violet (very weak bases) are used as indicators in this type of titration. A typical analysis is shown in Figure 3.8 for LDOPA. 

Acetic Acid. Addition of acetic acid to potassium hydroxide may cause eruption of the mixture.2... 

Effect of Acetic Acid. Addition of acetic acid (35 X 10 2 mole/ liter) to a solution containing Tetralin hydroperoxide (2.0 X 10 2 mole/ liter) and dilauryl thiodipropionate (2.5 X 10 2 mole/liter) not only eliminated the 60-minute induction period but substantially increased the rate of reaction (Figure 5). The over-all rate equation in the presence of acetic acid at 70°C., determined by the initial slopes method was... 

We have already alluded above to addition of bromine to [4.2.1]propell-3-ene. The saturated hydrocarbon also adds bromine to the conjoining bond at — 78°C, a reaction analogous to that of acetic acid addition. The same [4.2.1]olefin is hydrogenolyzed across the conjoining bond if platinum is used in acetic acid in ether the [4.2.1]propellane survives. 

In general, the cyclopropanones which have been prepared by the above routes are too unstable to be isolated, and are therefore usually trapped by alcohols, amines or as other carbonyl addition products. One particularly useful, stable cyclopropanone source is the acetic acid addition product reported by van Tilborg . This material can easily be purified, and readily yields the parent ketone in situ on reaction with nucleophiles. A summary of cyclopropanones prepared by this route has been reported. ... 

Most compounds in the study of Mallet et al. [102] respond similarly to the addition of acetic formic acid, although the effect is compound dependent. In negative-ion mode (Figure 6.5), most compounds are ion suppressed by formic and acetic acid additives. Anunoiuum hydroxide results in (significant) response enhancement for some compounds, e.g, raffinose, while the response of other compounds, e.g., malic acid and etidronic acid, is strongly suppressed. 

Table V. Effect of Acetic Acid Addition on Calcite Solubility. Modeled with...

The first example of a benzodiazepine, the 2,4-dimethyl derivative (1, R = R" = Me, R = H) was prepared in 1907 by Thiele2 by condensation of o-phenylenediamine with acetylacetone in ethanol-acetic acid. Addition of hydrochloric acid precipitated the purple hydrochloride.2 The commonest method of preparation remains the reaction of o-phenylenediamine with /3-dicarbonyl compounds. 

Thus, the ionic strength increase is offset by the formation of associated acid. Acetic acid additionally is a good choice of cathode depolarizer since most metal acetate salts are soluble. 

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