Butter rancid

Butanoic acid, CH3CH2CH2COOH, colourless syrupy liquid with a strong odour of rancid butter b.p. (sTC. Occurs in butter as the glycerol ester. Prepared by oxidation of 1 -butanol or by the fermentation of sugary or starchy materials by B. subtilis etc. Oxidized... 

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... 

Observable Characteristics - Physical State (as normally shipped) Liquid Color. Clear Odor. Rancid, disagreeable strong, penetrating, like rancid butter. 

Many carboxylic acids were first isolated from natural sources and were given names based on their origin. Fonnic acid (Latin formica, meaning ant ) was obtained by distilling ants. Since ancient times acetic acid (Latin acetum, for vinegar ) has been known to be present in wine that has turned sour. Butyric acid (Latin butyrum, meaning butter ) contributes to the odor of both rancid butter and ginkgo benies, and lactic acid (Latin lac, for milk ) has been isolated from sour milk. 

Butyric acid, CgHy. COOH, is an oily liquid ha-ving an odour of rancid butter. It has been found in the oils of Eucalyptus globulus, Heracleum giganteum, and in nutmeg, niaouli, and other essential oils. It has the following characters —... 

Butyric add, HC4Ht02, is responsible for the odor of rancid butter and cheese. Its K is 1.51 X 10 5. Calculate [H+] in solutions prepared by adding enough water to the following to make 1.30 L. 

Butyric acid, a component of rancid butter, has a vile stench. Burning 0.440 g of butyric acid in excess oxygen yields 0.882 g of CO2 and 0.360 g of H2 O as the only products. The molar mass of butyric acid is 88 g/mol. What are its empirical formula and molecular formula ... 

Colorless oily liquid with a pungent putrid odor like rancid butter or vomit detectable at 0.003-2.5 ppm. Various salts have been reported. 

The word butter comes from the Greek butyros. Butanoic acid (common name butyric acid) gives rancid butter its distinctive odour. Calculate the pH of a 1.0 x 10 mol/L solution of butanoic acid... 

Since carboxylic acids are amongst the earliest organic compounds to be isolated from nature, a large number of them are known by their common names. The common names end with the suffix -ic acid and have been derived from Latin or Greek names of their natural sources. For example, formic acid (HCOOH) was first obtained from red ants (Latin formica means ant), acetic acid (CH C OOH) from vinegar (Latin acetum, means vinegar), but n ic acid (CH3CH2CH2COOH) from rancid butter (Latin butyrum, means butter). 

This is because pure acetic acid freezes at 17°C, which is slightly below room temperature. When bottles of pure acetic acid froze in cold labs, snow-like crystals formed on the bottles the term glacial was thus associated with the pure form. Butyric acid comes from the Latin word butyrum for butter butyric acid is responsible for the smell of rancid butter. 

Soap prepared from fish oil is very similar to the last named. God-liver oil soap differs only in having a more unpleasant smell and less consistency. Suet or tallow soap is white and solid, and has a slight odor of the fat. Exposed to the air, it loses water, and becomes brittle. Soap prepared from lard is very white, solid, inodorous, and especially valuable for the production of toilet soaps. Rancid butter yields a soap whieh is white, and in properties similar to tallow soap, but retains a rancid smell. Castor oil and spermaceti soaps are emollient, and especially applicable to toilet pur-... 

Many fatty acids of lower molecular weight have a bad odor. Speculate as to the reasons why rancid butter has a bad odor. What chemical compound is produced that has a bad odor What sort of chemical reaction is involved in its production ... 

When fats or oils are exposed to air, they react with the oxygen or water vapor to form short-chain carboxylic acids. The short-chain acids are volatile and have unpleasant smells and tastes. For example, the strong smell and sour taste of vinegar are due to acetic acid, a two-carbon carboxylic acid. The oxidation process is called rancidification and can make foods unpalatable. The characteristic smell of rancid butter is due to the presence of butyric acid (a four-carbon acid). (Rancidity can also be the result of the hydrolysis of fats or oils.)... 

This is quite undesirable in a perfume because many carboxylic acids have objectionable odors. For example, the sharp, penetrating odor of vinegar is due to acetic acid, butanoic acid (butyric acid) smells like rancid butter, and 2-methylpropanoic acid (isobutyric acid) is a component of sweat. A common name for hexanoic acid is caproic acid, derived from the Latin word caper, which means goat. If you have ever been around goats, perhaps you can imagine the odor of hexanoic acid. 

Butanoic acid (butyric acid) (rancid butter)... 

Aldehydes and ketones are also important components of many fragrances and flavors. For example, butanal (butyraldehyde) is used to impart a buttery flavor to margarine and other foods. Because aldehydes are slowly oxidized to carboxylic acids by the oxygen of air, it is readily apparent how the odor of rancid butter arises. Although a-pentylcinnamaldehyde does not occur naturally, it has been found to have a powerful jasmine odor and is used in many perfumes and soaps, a-lonone is a naturally oc-... 

Woo, A.H., Lindsay, R.C. 1983b. Stepwise discriminant analysis of free fatty acid profiles for identifying sources of lipolytic enzymes in rancid butter. J. Dairy Sci. 66, 2070-2075. 

Systematic names for carboxylic acids use the -oic acid suffix, but historical names are commonly used. Formic acid was first isolated from ants, genus Formica. Acetic acid, found in vinegar, gets its name from the Latin word for sour (acetum). Propionic acid gives the tangy flavor to sharp cheeses, and butyric acid provides the pungent aroma of rancid butter. 

Polystyrene Polyvinyl bulyral Nylon 1.05-1.08 Orange yellow 1.07-1.08 Blue mantle yellow 1.09-1.14 Bluemanlle yellow Yes Yes (trans.) Yes Black Dense Sweet marigolds Rancid butter Burn hair Diethyl benzene... 

Methyl Propanoic Acid of rancid butter ins—water/ ... 

Ketones often have useful solvent properties (acetone is found in nail polish remover, for example) and are frequently used in industry for this purpose. Aldehydes typically have strong odors. Vanillin is responsible for the pleasant odor in vanilla beans cinnamaldehyde produces the characteristic odor of cinnamon. On the other hand, the unpleasant odor in rancid butter arises from the presence of butyraldehyde. 

DOT UN 2529 mf C4H8O2 mw 88.12 PROP Colorless liquid pungent odor of rancid butter. Mp —47°, bp 118-119° 35 mm, flash p 132°F (TOC), d 0.949 20°/4°, refr index 1.392, vap press 1 mm 14.7°, vap d 3.04, autoign temp 935°F. Misc with ale, chloroform, ether, fixed oils, glycerin, propylene glycol insol in water. SYNS ACETIC ACID, DIMETHYL- DIMETHYL-ACETIC ACID FEMA No. 2222 ISOBUTYRIC ACID (DOT) ISOPROPYLFORMIC ACID KYSELINA ISOMASEIA A a-METHYLPROPIONIC ACID 2-METHYLPROPIONIC ACID PROPIONIC ACID, 2-xMETHTT.-... 

The next two acids in the series are propionic acid, CH3CH2COOH, and butyric acid, CHgCHgCHgCOOH. Butyric acid is the principal odorous substance in rancid butter. 

The aliphatic carboxylic acids have been known for a long time, and as a result have common names that refer to their sources rather than to their chemical structures. The common names of the more important acids are shown in Table 18.1. Formic acid, for example, adds the sting to the bite of an ant (Latin formicQy ant) butyric acid gives rancid butter its typical smell (Latin butyrum, butter) ... 

Butyric acid, whose empirical formula is C2H4O, is the acid responsible for the odor of rancid butter. The acid has one ionizable hydrogen per molecule. A 1.000-g sample of butyric acid is neutrahzed by 54.42 mL of 0.2088 M NaOH solution. What are (a) the molecular weight and (b) the molecular formula of butyric acid ... 

The gas could be either ethyl acetate or butyric acid. Both have the formula C4H8O2. They have very different odors, however. Ethyl acetate has the odor of nail polish remover. Butyric acid has the foul odor of rancid butter. 

Formic acid was obtained by distillation of ants (L. formica, ant ) acetic acid occurs in vinegar (L. acetum, vinegar ) butyric acid in rancid butter (L. butyrum, butter ) and stearic acid in animal fats (Gr. stear, beef suet ). Caproic acid is one of the so-called goat acids. Its odor is responsible for the name. 

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