Cyclization of 4-ureidobutanoic acids in acetic anhydride

A simple method is proposed for synthesizing 1-carbamoyl-2-pyrrolidones by cyclization of 4-ureidobutanoic acids in acetic anhydride.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 33–38, January, 1995.     

Determination of formic and acetic acids in air by piezoelectric microweighing

The quantitative and kinetic parameters of sorption of formic and acetic acids on thin films of various modifiers of piezoelectric quartz resonator electrodes are determined. Parameters of film formation on the electrodes (application procedure and thickness) are optimized. Methods for joint and separate determination of formic and acetic acids in air by piezoelectric microweighing with single- and double-sensor devices are developed.     

Production of formic and acetic acids from phenol by hydrothermal oxidation

Hydrothermal technology is a core environmental-protection technique which can be used for waste water treatment and biomass conversion. In this paper a novel idea, alkaline hydrothermal oxidation, is proposed for producing formic and acetic acids from wastewater containing phenolic compounds. The effects of the most important conditions??reaction temperature, reaction time, oxygen supply, and type of alkaline catalyst??on yields of formic and acetic acids were investigated. The results indicated that the optimum conditions for production of formic and acetic acids were: reaction temperature 300???C, reaction time 90?s, H₂O₂ equivalent to 60% oxygen, and NaOH concentration 1.5?mmol. Under the optimum conditions the yields of formic and acetic acids reached 4.8 and 23.5%, respectively. In addition, the effect of different alkalis on yields of formic and acetic acids was also investigated. The results showed that compared with use of NaOH addition of KOH had a more pronounced effect on improving the yield of acetic acid. This research indicated that high-value-added formic and acetic acids can be recovered as resources by hydrothermal oxidation of phenolic wastewater, and thus hydrothermal oxidation has high potential for converting phenolic compounds in wastewater into value-added products.     

Acetoformic anhydride in the synthesis of chromones. 1. Synthesis of 3-hetarylchromones

It was shown that the reaction of -(het)aryl-2,4-dihydroxy- and 2,4,6-trihydroxyacetophenones with acetoformic anhydride catalyzed by sodium formate is an effective method for the preparation of chromones containing a heteroaromatic residue at the 3-position. The yield of the chromone and the rate of the reaction increase with increase in the -deficiency of this residue or in the presence of a hydroxy group in the 6-position of the starting acetophenone. In the last case the method is also applicable to the preparation of the difficulty available 3-aryl-5,7-dihydroxychromones. Chromones with a nitrogencontaining residue are formed without the use of any catalyst.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 625–631, May, 1991.     

Heats of solution and neutralization ofLewis acids and bases in acetic anhydride

Heats solution of someLewis acids and bases in acetic anhydride have been determined and the following order of their relative strengths is proposed: SbCl₅>SO₃>SnCl₄>TiCl₄>AsCl₃ and piperidine> n-butylamine>potassium acetate>sodium acetate -picoline>quinoline. Heats neutralization of theseLewis acids and bases in acetic anhydride suggest that the major enthalpy change in these neutralization reactions is due to the combination of a proton and the (CH₂COOCOCH₃)-ion, resulting in the formation of acetic anhydride.

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Lösungs- und Neutralisationswärmen von Lewis-Säuren und-Basen in Essigsäureanhydrid

Zusammenfassung Es wurden die Lösungswärmen einigerLewis-Säuren in Essigsäureanhydrid bestimmt und folgende Reihung nach ihrer relativen Stärke vorgeschlagen: SbCl₅>SO₃>SnCl₄>TiCl₄>AsCl₃ und Piperidin> n-Butylamin>KAc>NaAc-Picolin>Chinolin. Die Neutralisationswärmen dieserLewis-Säuren und-Basen legen nahe, daß der Hauptanteil daran auf die Reaktion eines Protons mit (CH₂–COOCOCH₃)-zurückzuführen ist.

     

Ultramicro detection of formic,acetic and some other volatile organic acids

Summary Ultramicro procedures for the detection of formic, acetic, propionic, butyric, valeric and monochloracetic acid are proposed. Formic, acetic and monochloracetic acids may be specifically identified, but no distinction of the rest is possible.

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Zusammenfassung Ultramikroverfahren zum Nachweis von Ameisensäure, Essigsäure, Propionsäure, Buttersäure, Valeriansäure und Monochloressigsäure wurden vorgeschlagen. Ameisen-, Essig- und Monochloressigsäure lassen sich spezifisch nachweisen, die anderen aber nicht voneinander unterscheiden.

     

First principles study of the reaction of formic and acetic acids with hydroxyl radicals

The oxidation of formic and acetic acids with hydroxyl radicals was studied as a model for the oxidation of larger carboxylic acids using first principles calculations. For formic acid, the CBS-QB3 activation barriers of 14.1 and 12.4 kJ/mol for the acid and for the formyl channel, respectively, are within 3 kJ/mol of benchmark W1U values. Tunneling significantly enhances the rate coefficient for the acid channel and is responsible for the dominance of the acid channel at 298 K. At 298 K, tunneling correction factors of 339 and 2.0 were calculated for the acid and the formyl channel using the small-curvature tunneling method and the CBS-QB3 potential energy surface. The Wigner, Eckart, and zero-curvature tunneling methods severely underestimate the importance of tunneling for the acid channel. The resulting reaction rate coefficient of 0.98 x 10(5) m(3)/(mol x s) at 298 K is within a factor 2-3 of experimental values. For acetic acid, an activation barrier of 11.0 kJ/mol and a tunneling correction factor of 199 were calculated for the acid channel. Two mechanisms compete for hydrogen abstraction at the methyl group, with activation barriers of 11.9 and 12.5 kJ/mol and tunneling correction factors of 9.1 and 4.1 at 298 K. The resulting rate coefficient of 1.2 x 10(5) m(3)/(mol x s) at 298 K and branching ratio of 94% compare well with experimental data.     

Needle trap extraction for GC analysis of formic and acetic acids in aqueous solution

Formic and acetic acids are ubiquitous in the environment, food, and most of the natural products. Extraction of the acids from aqueous solution is required for their isotope analysis by the gas chromatography-isotope ratio mass spectrometry. To this objective, we have previously developed a purge-and-trap technique using the dynamic solid-phase microextraction technology, the NeedlEX. The extraction efficiency, however, remains unexamined. Here, we address this question using the flame ionization detector and isotope ratio mass spectrometer while comparing it with that of the CAR/PDMS fiber. The results show that the NeedlEX is applicable at a wide range of concentration through coordination of purge volume given the minimum amount 3.7 ng and 1.8 ng of formic and acetic, respectively, is extracted. The efficiency of NeedlEX was 6-7 times lower than the fiber at 1000 μg/mL depending on the analyte. It is, however, superior to the latter at 10 μg/mL or less owing to its lower detection limit. The extraction efficiency of both acids is equivalent in molar amount. This is, however, disguised by the different response of the flame ionization detector. The isotope ratio mass spectrometor overcomes this problem but is compromised by relatively large errors. These results are particularly useful for isotopic analysis of carboxylic acids.     

Osmotic and activity coefficients of the sodium salts of formic,acetic and propionic acids

Osmotic and activity coefficients are reported for the sodium salts of formic, acetic and propionic acids to the limits of their solubilities. Hydration of the second kind appears to increase with the length of the hydrocarbon chains. The onset of micelle formation is indicated in the more concentrated sodium propionate solutions.     

Coulometric generation of acetylions by oxidation of mercury in acetic anhydride and in acetic acid/acetic anhydride mixture

Coulometric generation of acetyl (CH₃CO⁺) ions by oxidation of mercury in acetic anhydride and in acetic acid/acetic anhydride (5:95, v/v) is described. Current/potential curves for solvents, titrated bases, indicator and mercury showed that in both these solvents mercury is oxidized at potentials which are much more negative than those for the titrated bases and other components present in the solution. Quinoline, triethanolamine, triethylamine, pyridine and quinolin-8-ol in acetic anhydride, as well as triethylamine, 2,2′-bipyridine, 2,4,6-collidine, pyridine and sodium acetate in acetic acid/acetic anhydride were titrated with acetyl ions generated by the oxidation of mercury. In this way, it was established that the oxidation of mercury to mercury (I) ions proceeds quantitatively with 100% current efficiency.     

Direct conversion of corn cob to formic and acetic acids over nano oxide catalysts

Considering energy shortage, large molecules in corn cob and easy separation of solid catalysts, nano oxides are used to transform corn cob into useful chemicals. Because of the microcrystals, nano oxides offer enough accessible sites for cellulose, hemicellulose and monosaccharide from corn cob hydrolysis and oxidant. Chemical conversion of corn cob to organic acids is investigated over nano ceria, alumina, titania and zirconia under various atmospheres. Liquid products are mainly formic and acetic acids. A small amount of other compounds, such as D-xylose,D-glucose, arabinose and xylitol are also detected simultaneously. The yield of organic acids reaches 25%–29% over the nano oxide of ceria,zirconia and alumina with 3 h reaction time under 453 K and 1.2 MPa O2. The unique and fast conversion of corn cob is directly approached over the nano oxides. The results are comparative to those of biofermentation and offer an alternative method in chemically catalytic conversion of corn cob to useful chemicals in a one-pot chemical process.     

The formation of symmetrical diaminoketones by the action of acetic anhydride on acetyl-N-methylamino acids

Summary When acetyl-N-methylamino acids are heated with acetic anhydride, bis-acetyl derivatives of N,N-dimethyl-, -diaminoketones are formed.Khimiya Prirodnykh Soedinenii, Vol. 2, No. 5, pp. 344–348, 1966