Potassium propanoate

Propanoic acid can be used to prepare the salt potassium propanoate, GHjCH COOK. Explain why potassium propanoate solution has a pH greater than 7. In your answer, you should mention the two equilibria Involved. 

In both equations the position of equilibrium lies well over to the left-hand side, i.e. to the reactant side. When potassium propanoate dissolves in water, the propanoate ions react with the hydrogen ions from the water to form propanoic acid molecules. This effectively removes some of the H+(aq) ions and so there will be fewer hydrogen ions than hydroxide ions present and the solution is alkaline. 

Any soluble salt of propanoic acid and a strong base would be suitable. Acceptable answers include sodium propanoate or potassium propanoate. 

Name of the carboxylic acid salt Potassium propanoate... 

The Perkin condensation is an aldol-type condensation in which an aromatic aldehyde (ArCHO) reacts with a carboxyUc acid anhydride, (RCH2C0)20, to give an a,j8-unsaturated acid (ArCH = CRCO2H). The catalyst that is usually employed is the potassium salt of the carboxylic acid (RCH2CO2K). (a) Outline the Perkin condensation that takes place when benzaldehyde reacts with propanoic anhydride in the presence of potassium propanoate. (b) How would you use a Perkin condensation to prepare />-chlorocinnamic acid, />-CIC6H4CH = CHC02H ... 

Collum and Rai [86] use the more easily available pjis(potassium propanoate) (hydroxy)]stannane, which, in the presence of NaBH4 and ACVA, affords reductions and free-radical cyclizations of aryl and alkenyl bromides ... 

Isobutyl alcohol, isobutanol, 2-methyl-propanol, isopropyl carbinol, Me2CHCH20H. B.p. 108°C. Occurs in fusel-oil. Oxidized by potassium permanganate to 2-methyl-propanoic acid dehydrated by strong sulphuric acid to 2-methylpropene. 

Electrolysis of carboxylic acid salts m solution causes decaboxyladve coupling similar to Kolbe reaction. Thus, eleclrolysis of 3,3,3-trifluoro-2-trifluoromethyl-propanoic acid in die presence of some of its potassium salt gives the corresponding fluoroalkane in a satisfactory yield [7d] (equation 67). 

To a stirred solution of (1.5 mmol) of LDA in 3.5 mL of THF/hcxane (60 40) at — 78 C under a nitrogen atmosphere is added 198 mg (1.5 mmol) terf-butyl propanoate in 1.5 mL of HMPA. After 30 min 169 mg (1.5 mmol) of potassium rm-butoxide are added and the mixture is stirred for 10 min. Then 133 mg (0.5 mmol) of ethyl 6-iodo-2-hcxcnoatc in 1.5 mL of TI1F arc added and the mixture is stirred for an additional 0.5 h at — 78 C. The reaction is quenched by adding sat. aq NH4C1. Extraction with ethyl acetate, drying over Na,S04 followed by evaporation of the solvent and short-path distillation gives the adduct yield 135 mg (100%). 

Some of the propanal is oxidised to propanoic acid by heating it with acidified potassium dichromate solution. 

Kolbe noted also the formation of traces of methyl acetate and butyl valerate from electrolysis of acetate and valerate respectively. Careful analysis of reaction products by Petersen (1900) identified compounds which are today formulated as being derived from carbocations formed by loss of one electron from the alkyl radical [50]. Propanoic acid gives mostly ethene while butanoic acid and 2-methyl-propanoic acid give mostly propene. Acetate and long chain alkylcarboxylates give mostly the Kolbe type dimer hydrocarbon on electrolysis of their potassium salts in concentrated solution at a platinum electrode, using high current density and low temperatures [51]. 

Potassium methyl a-[(methoxyethylidene)amino]-p-hydroxyacrylate Propanoic acid, 2-[(1-methoxyethylidene)amino]-3-oxo-, methyl ester, ion(l-), potassium (11) (105205-36-5) Potassium tert-butoxide tert-Butyl alcohol, potassium salt (8) 2-Propanol, 2-methyl-, potassium salt (9) (865-47-4)... 

F-marked potassium fluoride has been prepared and used to convert ethyl 2-bromo-propanoate (11) to the corresponding l8F-substituted derivative 12.50... 

Esters and acid fluorides give88 product mixtures very similar to those produced from ketones. Cobalt(III) fluoride again causes complete degradation, but potassium tetrafluoro-cobaltate(lll) gives polyfluoro acid fluorides, which are isolated by conversion to their ethyl esters yields are poor (ca. 20%) in all cases. Methyl propanoate reacts with potassium tetra-fluorocobaltate(III) at 350 CC to give a 5 2 2 mixture of ethyl 2,2-difluoropropanoate, ethyl... 

The fluorination of propanonitrile" was very reminiscent of methyl propanoate and pro-panoyl fluoride (Section 25.1.1.3.), in that replacement of the cc-fluorines is favored over the fi. Again cobalt(III) fluoride (205°C) and potassium tetrafluorocobaltate(III) (335°C) give similar product mixtures albeit at different temperatures. Yields are better over potassium tetra-fluorocobaltate(III) (> 40%) and the major product is 2-fluoropropanonitrile followed by 2,2-di-, 2,2,3-tri- and 2,2,3,3-tetrafluoropropanonitrile. 

Apart from sotolon, the other compounds in Fig. 5 can be explained as the products of a Maillard reaction, and their carbon skeletons simply originate from the active Amadori intermediate in other words, they still preserve the straight carbon chain structure of monosaccharides. In spite of being a simple Cg lactone, sotolon has a branched carbon skeleton, which implies another formation process in the Maillard reaction. Sulser e al.(6) reported that ethyl sotolon (ll) was prepared from threonine with sulfuric acid, and that 2-oxobutyric acid, a degradation product of threonine, was a better starting material to obtain II. This final reaction is a Claisen type of condensation, which would proceed more smoothly under alkaline conditions. As we(lO) obtained II from 2-oxobutyric acid (see figure 6) with a high yield in the presence of potassium carbonate in ethanol, a mixed condensation of 2-oxobutyric and 2-oxo-propanoic (pyruvic) acids was attempted under the same conditions, and a mixture of sotolon (22% yield) and II were obtained however, the... 

Synonyms E283 propanoic acid, potassium salt propionic acid, potassium salt. 

Treatment of 3-(l-benzyloxymethylcyclopropyl)propanoic acid with various mercury(II) salts such as nitrate, trifluoroacetate and perchlorate gave the lactones 25A and 25B in 35-86% yield after aqueous potassium bromide workup. A number of related cyclopropanecarboxylic esters were reacted in the same fashion to give bromomercurio-substituted lactones 26 and 27/28 from which the mercury was removed by reduction with sodium borohydride. ... 

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