A new route to 5-bromo-5′-bromomethylpyrromethenes

1978 ◽  
Vol 56 (14) ◽  
pp. 1907-1912 ◽  
Author(s):  
Arend Rowold ◽  
S. Ferguson MacDonald
Keyword(s):  
Acetic Acid ◽  
Carboxylic Acids ◽  
Propionic Acid ◽  
Room Temperature

Esters of hitherto inaccessible 5-bromo-5′-bromomethylpyrromethenes, with alternating acetic acid (or methyl) and propionic acid groups in the (β positions, are obtained by brominating the appropriate 5-acetoxymethylpyrrole-2-carboxylic acids in ethanol-free chloroform at ≤10 °C. The bromomethylpyrromethenes give the corresponding methoxymethylpyrromethenes in methanol at room temperature.

scholarly journals Heterogeneous chemistry of monocarboxylic acids on α-Al<sub>2</sub>O<sub>3</sub> at ambient condition

2010 ◽  
Vol 10 (2) ◽  
pp. 3937-3974 ◽  
Author(s):  
S. R. Tong ◽  
L. Y. Wu ◽  
M. F. Ge ◽  
W. G. Wang ◽  
Z. F. Pu
Keyword(s):  
Acetic Acid ◽  
Formic Acid ◽  
Carboxylic Acids ◽  
Propionic Acid ◽  
Ambient Condition ◽  
Heterogeneous Reactions ◽  
Dust Particles ◽  
Monocarboxylic Acids ◽  
Al2o3 Particles ◽  
Α Al2o3

Abstract. A study of the atmospheric heterogeneous reactions of formic acid, acetic acid, and propionic acid on dust particles (α-Al2O3) was performed at ambient condition by using a diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) reactor. From the analysis of the spectral features, observations of carboxylates formation provide strong evidence for an efficient reactive uptake process. Comparison of the calculated and experimental vibrational frequencies of adsorbed carboxylates establishes the bridging coordinated structures on the surface. The uptake coefficients of formic acid, acetic acid, and propionic acid on α-Al2O3 particles are (2.07±0.26)×10−3, (5.00±0.69)×10−3, and (3.04±0.63)×10−3, respectively (using geometric area). Besides, the effect of various relative humid (RH) on this heterogeneous reactions was studied. The uptake coefficients of monocarboxylic acids on α-Al2O3 particles increase initially (RH<20%) and then decrease with the increased RH (RH>20%) which was due to the effect of water on carboxylic acids solvation, particles surface hydroxylation, and competition on reactive site. On the basis of the results of experimental simulation, the mechanism of heterogeneous reaction of dust with carboxylic acids at ambient condition was discussed. The loss of atmospheric monocarboxylic acids due to reactive uptake on available mineral dust particles can be competitive with homogeneous loss pathways, especially in dusty urban and desertified environments.

Excess Gibbs energy for binary mixtures of acetonitrile with acetic acid, propionic acid, isobutyric acid, and trimethylacetic acid

1991 ◽  
Vol 69 (12) ◽  
pp. 2117-2121 ◽  
Author(s):  
T. S. Banipal ◽  
B. S. Lark ◽  
S. Singh
Keyword(s):  
Acetic Acid ◽  
Gibbs Energy ◽  
Carboxylic Acids ◽  
Propionic Acid ◽  
Binary Mixtures ◽  
Activity Coefficients ◽  
Excess Gibbs Energy ◽  
Composition Range ◽  
Isobutyric Acid ◽  
Dimerization Constant

Total vapour pressures for binary mixtures containing acetic acid, propionic acid, isobutyric acid, and trimethylacetic acid with acetonitrile have been measured for the entire composition range at 298.15 and 318.15 K using a static manometric method. All systems show positive deviations from Raoult's law, enhanced by both an increase in temperature and an increase in the methylation of acetic acid. Activity coefficients have been calculated by taking into consideration the dimerization of these carboxylic acids in the vapour phase. TSE values obtained from GE and earlier reported HE values are found to be negative for acetic acid, about zero for propionic and isobutyric acids, and positive for trimethylacetic acid for the whole composition range. The results have been interpreted in terms of various contributions such as depolymerization, heteromolecular dipole–dipole interactions, and the increasing dimerization constant and steric hindrance with increase of complexity of the acid. Key words: excess Gibbs energy, carboxylic acids, acetonitrile, activity coefficients

New oxidation products of tryptophan

1975 ◽  
Vol 28 (10) ◽  
pp. 2275 ◽  
Author(s):  
WE Savige
Keyword(s):  
Acetic Acid ◽  
Carboxylic Acid ◽  
Propionic Acid ◽  
Alkaline Solution ◽  
Sodium Borohydride ◽  
Room Temperature ◽  
Oxidation Products ◽  
Acid Oxidation ◽  
Peroxyacetic Acid ◽  
Molar Equivalent

Oxidation of L- or DL-tryptophan by one molar equivalent of peroxyacetic acid in water at 0-5� gives principally a mixture of 3a- hydroxy-1,2,3,3a,8,8a-hexahydropyrrolo[2,3-b]indole-2-carboxylic acid (A) diastereoisomers, while oxidation by two or three equivalents of oxidant gives mainly N?-formylkynurenine (C11H12N2O4) and a diastereoisomeric product (B), C11H12N2O5, tentatively assigned the structure 2-amino-3-(4-hydroxy-2-oxo-1,4-dihydro-2H-3,1-benzoxazin-4- yl)propionic acid. ��� Oxidation of (A) by peroxyacetic acid also gives formylkynurenine and (B). Rearrangement of (A) to oxindolylalanine occurs in 12N HCl at 20� or 2N HCl at 80�. (A) is also obtained by reduction of dioxindolylalanine with sodium borohydride. Compound (B) readily undergoes decarboxylation to kynurenine in 0.1N acetic acid at 80�, while in neutral or alkaline solution rapid autoxidation can occur even at room temperature.

An ion cyclotron resonance study of competitive solvation of gas phase anions

1979 ◽  
Vol 57 (5) ◽  
pp. 473-477 ◽  
Author(s):  
R. L. Clair ◽  
T. B. McMahon
Keyword(s):  
Acetic Acid ◽  
Gas Phase ◽  
Carboxylic Acids ◽  
Propionic Acid ◽  
Cyclotron Resonance ◽  
Binding Energies ◽  
Ion Cyclotron Resonance ◽  
Fluoride Ions ◽  
Carboxylate Anions ◽  
Anion Transfer

Reactions of trifluoromethoxide ion, CF3O−, with carboxylic acids have been examined. Facile fluoride transfer is observed to occur to the acids and a subsequent fluoride transfer equilibrium established in mixtures of carboxylic acids. From the equilibrium constant obtained for fluoride transfer acetic acid and propionic acid are found to have near identical fluoride binding energies. Further reaction between the acid solvated fluoride ions and the carboxylic acids is observed to occur resulting in HF displacement and formation of bicarboxylate anions. In mixtures of acetic and propionic acids acetate and propionate anion transfer equilibria are again established. An analysis of the energetics for these processes reveals that propionic acid binds the carboxylate anions more strongly than acetic acid by 0.1 to 0.2 kcal/mol.

scholarly journals Carboxylic acid recovery from Fischer–Tropsch aqueous product by fractional freezing

2020 ◽  
Vol 10 (3) ◽  
pp. 149-156
Author(s):  
Nuvaid Ahad ◽  
Arno de Klerk
Keyword(s):  
Acetic Acid ◽  
Liquid Phase ◽  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Propionic Acid ◽  
Butyric Acid ◽  
Acid Water ◽  
Liquid Equilibrium ◽  
Fischer Tropsch ◽  
Solid Liquid

Abstract About half of the product from iron-based high-temperature Fischer–Tropsch synthesis is an aqueous product containing dissolved oxygenates. Volatile oxygenates can be recovered by distillation, but the bulk of the carboxylic acids remain in the water, which is called acid water. Fractional freezing was explored as a process for producing a more concentrated carboxylic acid solution from which the carboxylic acids could be recovered as petrochemical products, while concomitantly producing a cleaner wastewater. Solid–liquid equilibrium data were collected for aqueous solutions of acetic acid, propionic acid, and butyric acid. A synthetic Fischer–Tropsch acid water mixture (0.70 wt% acetic acid, 0.15 wt% propionic acid, and 0.15 wt% butyric acid) was prepared and the liquid phase concentrations of the acid species at solid–liquid equilibrium were determined. Control experiments with material balance closure on each of the carboxylic acid species were performed at selected conditions. Having more than one carboxylic acid species present in the mixture meaningfully changed the solid–liquid equilibrium versus temperature of the system. The carboxylic acids partitioned between the solid phase and the liquid phase and a practical design would require multiple duty-controlled solid–liquid equilibrium stages, with most of the separation taking place in the temperature range 0 to − 5 °C.

Esterification of Alkene with Cerium(IV) Sulfate in Carboxylic Acid

2003 ◽  
Vol 2003 (5) ◽  
pp. 270-272 ◽  
Author(s):  
C. Akira Horiuchi ◽  
Tomoaki Fukushima ◽  
Noriyuki Furuta ◽  
Wen Chai ◽  
Shun-Jun Ji ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Carboxylic Acid ◽  
Formic Acid ◽  
Carboxylic Acids ◽  
Propionic Acid ◽  
Addition Reaction ◽  
Simple Method ◽  
Markovnikov Rule ◽  
Carboxylic Esters

Reaction of alkenes [cyclohexene (1), cycloheptene (2), cyclooctene (3), 1-heptene (4), 1-octene (5), styrene (6), 1,7-octadiene (7), indene (8), and 1,2-dihydronaphthalene (9)] with cerium(IV) sulfate (CS) in carboxylic acids [formic acid, acetic acid, and propionic acid] readily yielded the corresponding carboxylic esters. This addition reaction follows the Markovnikov rule. This reaction provides a new simple method for preparing carboxylic esters from alkenes. It was also found that this method is useful for formylation.

Excess molar volumes of binary mixtures of acetic acid and propionic acid with some members of homologous series of alkanes

1991 ◽  
Vol 56 (4) ◽  
pp. 736-744 ◽  
Author(s):  
Ondřej Drábek ◽  
Ivan Cibulka
Keyword(s):  
Acetic Acid ◽  
Propionic Acid ◽  
Alkyl Chain ◽  
Excess Molar Volumes ◽  
Liquid Mixtures ◽  
Entire Concentration Range ◽  
Molar Volumes ◽  
Binary Liquid ◽  
Alkane Molecule ◽  
Increasing Temperature

Excess molar volumes of binary liquid mixtures of (acetic or propionic acid = hexane) at 25 and 35°C, and (acetic or propionic acid + heptane or octane) and (acetic acid + dodecane) at 25°C, measured with a tilting dilution dilatometer, are reported. The excess volumes are positive over the entire concentration range for all mixtures and increase with increasing length of an alkane molecule, decrease with increasing of the alkyl chain in a molecule of carboxylic acid, and increase with increasing temperature.

Vapour-liquid equilibrium in the ternary system cyclohexane-acetic acid-propionic acid

1989 ◽  
Vol 54 (11) ◽  
pp. 2840-2847 ◽  
Author(s):  
Ivona Malijevská ◽  
Alena Maštalková ◽  
Marie Sýsová
Keyword(s):  
Acetic Acid ◽  
Ternary System ◽  
Propionic Acid ◽  
Activity Coefficients ◽  
Error Propagation ◽  
Analytical Techniques ◽  
Liquid Equilibrium ◽  
Consistency Test ◽  
Propagation Law ◽  
Equilibrium Data

Isobaric equilibrium data (P = 101.3 kPa) for the system cyclohexane-acetic acid-propionic acid have been measured by two different analytical techniques. Activity coefficients calculated by simultaneous solving of equations for the chemical and phase equilibria were subjected to a consistency test based on inaccuracies determined from the error propagation law, and were correlated by Wilson’s equation. The activity coefficients measured were compared with those calculated from binary vapour-liquid equilibrium data and with values predicted by the UNIFAC method.

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