2- propionic acid,

Propionic acid is effective at reducing fungal growth, especially at lower pH, by affecting fungal membranes at pH values below 4.5. Similar to acetic acid, propionic acid also inhibits amino acid uptake. The salts of propionic acid, such as sodium propionate and ammonium propionate show a similar effect against yeasts and filamentous molds at a low pH (Schniirer and Magnusson, 2005). 

Propionic acid - calcium salt CA Index Name  

Ethancarboxylic acid Propianoic acid Ethylformic acid Methylacetic acid Luprosil Prozoin Tenox P E 280. 

German Propionsaure, French Acide propionic, Spanish Acido propionico. 

Sodium propionate Sodium ethanecarboxylate Sodium propanoate Propanoic acid, sodium salt Whit-Bioban-S Deketon Impedex Mycoban Napropion Ocuseptine Propi-Ophtal Propiofar Propion PropisolPro E 281. 

Calcium dipropionate Calcium propanoate Calcium propionate  

Propionic acid is found in nature where propionic acid fermetnation occurs, e. g., in Emmental cheese, in which it is present up to 1%. 

Its antimicrobial activity is mostly against molds, less so against bacteria. Propionic acid has practically no effect against yeast. Its activity is pH dependent. It is recommended and used up to pH 5 and only occasionally up to pH 6. 

Propionic acid is practically nontoxic. It is used as an additive in baked products for inhibition of molds, and to prevent ropiness caused by the action of Bacillus mesentericus. It is added to flour at 0.1-0.2% as its Ca-salt and is used in cheese manufacturing by dipping the cheese into an 8% solution of the acid. 

Carboxyethane ethanecarboxylic acid E280 ethylformic acid metacetonic acid methylacetic acid propanoic acid pseudo-acetic acid. 

Propionic acid is primarily used as an antioxidant and antimicrobial preservative in foods, and in oral and topical pharmaceutical applications. It is also used as an esterifying agent. 

Propionic acid occurs as a corrosive, oily liquid having a slightly pungent, disagreeable, rancid odor. It is flammable. 

Autoignition temperature 955°C Boiling point 141.1°C Dissociation constant pK = 4.874 Flash point 52-58°C (open cup) Melting point —21.5°C Partition coefficients Octanol water Refractive index = 1.3848 = 0.33. 

Solubility miscible with chloroform, ethanol 95%), ether, and  

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By contrast, in the system propionic acid d) - methyl isobutyl ketone (2), (fi and are very much different when y 1, Propionic acid has a strong tendency to dimerize with itself and only a weak tendency to dimerize with ketone also,the ketone has only a weak tendency to dimerize with itself. At acid-rich compositions, therefore, many acid molecules have dimerized but most ketone molecules are monomers. Acid-acid dimerization lowers the fugacity of acid and thus is well below unity. Because of acid-acid dimerization, the true mole fraction of ketone is signi-... 

Vapor-Phase Mole Fraction Propionic Acid... 

Figure 3-7. Fugacity coefficients for a saturated mixture of propionic acid (1) and raethylisobutylketone (2). Calculations based on chemical method show large variations from ideal behavior.

PROPIONIC ACID -9.0717E4O2 2 6352E4>04 -8 2603E-02 U7777E4 02... 

The ketones are readily prepared, for example, acetophenone from benzene, acetyl chloride (or acetic anhydride) and aluminium chloride by the Friedel and Crafts reaction ethyl benzyl ketones by passing a mixture of phenylacetic acid and propionic acid over thoria at 450° and n-propyl- p-phenylethylketone by circulating a mixture of hydrocinnamic acid and n-butyric acid over thoria (for further details, see under Aromatic Ketones, Sections IV,136, IV,137 and IV,141). 

The phenyl propionate may be prepared by slowly adding 196 g. (120 ml.) of redistilled thionyl chloride to a mixture of I50g. of pure phenol and 132 g. (133 ml.) of propionic acid (compare Fig. 111,31, 1), warming to drive all the sulphur dioxide and hydrogen chloride, and distilling 190 g. of phenyl propionate, b.p. 202-212° (the pure substance boils at 211°) are obtained. 

Ethyl benzyl ketone. Use 204 g. of phenylacetic acid (m.p. 77°) and 333 g. (335 -5 ml.) of propionic acid (b.p. 139-141°), but omit the extraction with benzene when working up the distillate. Distil the dried... 

Ethyl p-phenylethyl ketone. Use 100 g. of pure hydrocinnamic acid and 200 g. (201 -5 ml.) of pure propionic acid. Fractionation of the distillate yields 70 g. of diethyl ketone (b.p. 100-102°), 72 g. of ethyl p-phenyl-ethyl ketone (b.p. 245-249° the pure ketone boils at 248°), and 18 g, of crude di-p-phenylethyl ketone (high b.p. residue). 

The Stobbe condensation thus provides a method for introducing a propionic acid residue at the site of a carbonyl group. 

Takatori (274) formylated 2-amino-4-methylthiazole with formic acid. When NHj is bubbled for 6 hr into a mixture of 2-amino-4-methyl-thiazole and propionic acid at 100°C, 2-propionamido-4-methylthiazole is obtained (275). 

The three thiazoleacetic acids and higher homologs such as the derivatives of propionic acid have been synthesized (5), They are usually prepared by the Hantzsch s method, either as the free acid or as the ester from which the free acid is obtained by hydrolysis (49, 73). 

It IS hard to find a class of compounds in which the common names of its members have influenced organic nomenclature more than carboxylic acids Not only are the common names of carboxylic acids themselves abundant and widely used but the names of many other compounds are derived from them Benzene took its name from benzoic acid and propane from propionic acid not the other way around The name butane comes from butyric acid present m rancid butter The common names of most aldehydes are derived from the common names of carboxylic acids—valeraldehyde from valeric acid for exam pie Many carboxylic acids are better known by common names than by their systematic ones and the framers of the lUPAC rules have taken a liberal view toward accepting these common names as permissible alternatives to the systematic ones Table 19 1 lists both common and systematic names for a number of important carboxylic acids... 

Water Formic acid Butyric acid Water Formic acid Propionic acid Water... 

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