Propionic Acid Solutions Research Articles

Ultrasonic Absorption in Solutions of Propionic Acid

Abstract The effect of a solvent on the ultrasonic relaxation of propionic acid has been studied. The relaxation frequency is affected a little in hydrophilic solvents, while in non-hydrophilic solvents it shifts to a higher-frequency side. The activation enthalpy in a reaction from open to cyclic dimers decreases with dilution in the non-hydrophilic solvents; the magnitude of the change in the hydrophilic solvents is less than in the non-hydrophilic solvents. This means that the open dimer is destabilized by non-hydrophilic solvents. The sequence of the magnitude of the solvent effect on the relaxation frequency is consistent not with that estimated from the magnitude of the dielectric constant of the solvent, but with that estimated from the magnitude of the non-hydrophilic strength of the solvent. The stability of an open dimer in a hydrophilic or polar solvent is attributed to the interaction of the free OH group on the open dimer with the solvent.

Intermolecular nuclear relaxation and molecular pair distribution in liquid mixtures

7Li and 23Na relaxation times in aqueous solution of Li and Na in the presence of an increasing amount of Mn2 are reported. From these measurements the cation—cation pair distribution function has been calculated. A distance of approach between Li + (orNa ) and Mn2 + of 4.5 A has been found. The intermolecular proton relaxation rates of the acids CH3COOD, CH3CD2COOD, and CD3 CH2COOD dissolved in water (D20) are presented and from these data simple acid—acid pair distribution functions are constructed. Association has been detected from excess intermolecular proton—proton interactions. In the solution of propionic acid the association is stronger as seen from the methylene group than from the methyl group. In the pure alcohols CD3OH and C2D5OH and their mixtures with inert solvents intermolecular proton relaxation is entirely of rotational character and permits conclusions concerning the depth of the potential characterizing the pair distribution function.

The Anodic Oxidation of a Propionate-Propionic Acid Solution in the Presence of Several Organic Compounds

Abstract The anodic oxidation of the propionate anion in aqueous solutions of propionic acid at a platinum electrode has been studied in the presence of several organic compounds in order to demonstrate the formation of both propionoxy and ethyl radicals as the reaction intermediates. One of the following organic compounds was added to each solution: two vinyl monomers (acrylic acid and acrylamide), two alkylbenzenes (toluene and cumene), and two aliphatic alcohols (methanol and isopropanol). The electrooxidation of sodium propionate in the presence of acrylamide resulted in polymerization, which was confirmed to be initiated by the ethyl radical. Acrylic acid, unlike acrylamide, gave no polymers. In this case, both the current efficiency for the formation of carbon dioxide and the yield ratio of ethylene to carbon dioxide were always less than those observed in the absence of acrylic acid. While the addition of alcohols gave no definite results, the addition of toluene or cumene resulted in an appreciable decrease in the yield ratio of ethylene to carbon dioxide, but affecting neither the ratio of ethane to carbon dioxide nor the current efficiency for the carbon-dioxide evolution. These results indicate that the anodic oxidation of the propionate anion proceeds through the consecutive formation of propionoxy and ethyl radicals as the reaction intermediates.

Ultrasonic Absorption in Propionic Acid

The ultrasonic relaxational absorption in methyl propionate solutions of propionic acid has been studied in the frequency range 0.5–95 Mc/sec at concentrations varying from 0 to 1 mole fraction. The relaxation frequencies are 1.8, 2.2, 2.8, and 3.4 Mc/sec independent of the concentration at 20°, 25°, 30°, and 35°C, respectively. The independence of fmax on the concentration indicates that the ultrasonic relaxational absorption is associated with the uni—unimolecular reaction. The kinetic values have been calculated for the uni—unimolecular reaction by Tabuchi's theoretical equations. The forward and backward rate constants are 2.3×105 and 1.06×107 sec−1 at 20°C for pure propionic acid, respectively, and the heat of reaction is 4.7 kcal/mole of dimer. The value of Cpr is equal to that of Cvr, since the volume change resulting from reaction is absent. The consideration for the type of reaction, the magnitude of heat of reaction, and no volume change associated with reaction have led us to the conclusion that the ultrasonic absorption in propionic acid is associated with a breakage of one of two hydrogen bonds. The solvent effect on the relaxation mechanism has also been studied in various solvent solutions of propionic acid. The relaxation frequency fmax does not change with increasing concentration in polar solvent solutions, whereas it decreases with increasing concentration in nonpolar solvent solutions.

Voltammetric behavior of some selected metal ions in propionic, isobutyric and acrylic acids

The polarographic behavior of copper(II), copper(I), cadmium, lead(II), and thallium (I) ions and the voltammetric behavior of silver ion at the rotating platinum electrode in 1.0 M lithium perchlorate solutions of anhydrous propionic acid, isobutyric acid, and acrylic acid have been examined and compared with those in anhydrous acetic acid.

Techniques for Odor Measurement: Olfactometric vs. Sniffing

SUMMARYTwo techniques of odor testing, olfactometrie vs. sniffing, were compared with propionic acid used for the test odor. The olfactometer was more rapid and reliable as a technique for odor testing. Subjects appeared more sensitive by the sniff‐method, hut there were discrepancies in the data. The vapor phase above solutions of propionic acid in mineral oil was studied with propionic acid‐l‐C14. Evidence is presented for the existence of non ideal solutions. The significance of these data is discussed in terms of present techniques for odor testing, and their implications for future olfactory investigation.

Methylolation of Tall Oil Rosin

Abietic acid concentrated from tall oil rosin was reacted with formaldehyde rapidly (3060 min) in acetic acid (or propionic acid) solution to give 8, 9-bis- (methylene-acetoxy) -abietic acid which was isolated as the cyclohexylamine salt. From hydrolysis of this compound, 8, 9-dimethyloleabietic acid was obtained.The reactions of tall oil rosin with formaldehyde in absence of carboxylic acids or in inert solvent such as dioxane and benzene etc. were not proceeded, and tall oil rosin could be recovered unchanged in each case.But, condensation of tall oil rosin with formaldehyde was promoted in the presence of a small quantity of acetic acid, or even in higher fatty acid. The above reaction was also carried out in the presence of hydrochloric acid, but a large quantity of ether insoluble matters were obtained as the reaction products.

Studies on Kolbe's electrosynthesis

Measurements were made of the anode potentials that developed, and analyses were done of the anode gases obtained, at different current densities during the electrolysis of sodium salts of some homologues of acetic acid, as well as during the electrolysis of propionic acid solutions in the presence of fairly dilute sulphuric acid. The anode-potential/current -density curves show breaks in all those cases where saturated hydrocarbons are formed at the anode. Saturated hydrocarbons commence to be formed only at the critical potential, but no such restriction applies to the formation of olefines. The value of the critical potential lies in the neighbourhood of 2·1–2·2 V (EH) in all cases. In every case the Kolbe product is accompanied by a saturated hydrocarbon containing one carbon atom less than the acid.No hydrocarbons are found either in the anode gas obtained by the electrolysis of propionic acid solutions containing sulphuric acid or in the gas obtained by the interaction of hydrogen peroxide with propionic acid, both being a mixture of CO2 and O2. No alcohol or ester was found in the residual solutions, although in the former case the amount of oxygen at the anode is very much less that what it should be, showing that a good part of the anodic current is being used up in bringing about some reaction in solution.The cathode gas obtained with the different solutions contains saturated hydrocarbons in all cases.Mechanisms are suggested for the formation of various products at the anode.

Spectrophotometric determination of palladium(II) with 5 ( p-dimethylaminobenzylidene)rhodanine

A sensitive spectrophotometric method has been developed for tlie deternination (of pallaudium, busing 5( p-dimethylaminobenxylidene)rhodanine reagent in formic, hydrochloric, or propionic acid solution. The systems conform to Beer's law. The specific absorptivity is in the range 0.38 to 0.40 per p.p.m.-cm in the different solvents. The optimum range for 1.00-cm optical path is about 0.4 to 2.5 p.p.m. of palladium. At higher concentrations of palladium a violet-red precipitate forms within a few minutes. In propionic acid solution maximum color is attained at room temperature in 10 to 15 min, and is stable for more than two hours. The system is somewhat sensitive to hydrogen ion concentration; maximum absorbance and stability are attained at 0.01 N hydrochloric acid in tlie final .solution, Platinum (IV), ruthenium (III), iron(lll), iron (III), chromium (VI), and copper(ll) interfere if present in amounts several times greater than the amount of palladium ; gold(ll1) interferes very exensively. Tlie mole ratio method, the continuous variations method, and the slope ratio method all show the mple ratio of DMABR to palladium to be 2 : 1 in the color-forming reaction.

STUDIES ON ACETALDEHYDE EVOLUTION AND UTILIZATION

American Journal of BotanyVolume 41, Issue 10 p. 829-832 Article STUDIES ON ACETALDEHYDE EVOLUTION AND UTILIZATION James F. Nance, James F. NanceSearch for more papers by this authorYoshio Shigemura, Yoshio ShigemuraSearch for more papers by this author James F. Nance, James F. NanceSearch for more papers by this authorYoshio Shigemura, Yoshio ShigemuraSearch for more papers by this author First published: 01 December 1954 https://doi.org/10.1002/j.1537-2197.1954.tb14421.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume41, Issue10December 1954Pages 829-832 RelatedInformation

Handling avian chromosomes.

The somatic and meiotic chromosomes of Galius gal-lus dom. (as well as of the rat, mouse and possibly other animals) may be adequately prepared for miscroscopic examination by the following smear technic: Pith the fowl of appropriate age through the palatal fissure (other killing technics may be substituted for other animals), remove testes, slice medianly into halves (or quarters if large) and fix in mixture of 2 parts absolute ethanol, 1 part propionic acid, 1 part chloroform. Pour off and replace fixative at the end of 12-24 hours, after which the tissue may be stained or stored under refrigeration. Fresh material can be stained in propionic-carmine (0.5 g. carmine boiled in 45% aqueous solution of propionic acid), but material stored for several months should be stained in a boiled mixture of 10 ml. vinyl acetate, 10 ml. tertiary butyl alcohol, 50 ml. propionic acid, 75 ml. H2O, 0.25 g. carmine, 0.25 g. orcein. A method is described for preparing and making permanent such preparations.