Organic acids characteristics

The elemental and vitamin compositions of some representative yeasts are Hsted in Table 1. The principal carbon and energy sources for yeasts are carbohydrates (usually sugars), alcohols, and organic acids, as weU as a few other specific hydrocarbons. Nitrogen is usually suppHed as ammonia, urea, amino acids or oligopeptides. The main essential mineral elements are phosphoms (suppHed as phosphoric acid), and potassium, with smaller amounts of magnesium and trace amounts of copper, zinc, and iron. These requirements are characteristic of all yeasts. The vitamin requirements, however, differ among species. Eor laboratory and many industrial cultures, a commercial yeast extract contains all the required nutrients (see also Mineral nutrients). 

Properties are furthermore determined by the nature of the organic acid, the type of metal and its concentration, the presence of solvent and additives, and the method of manufacture. Higher melting points are characteristics of soaps made of high molecular-weight, straight-chain, saturated fatty acids. Branched-chain unsaturated fatty acids form soaps with lower melting points. Table 1 Hsts the properties of some soHd metal soaps. 

Carboxylic acids with one acid group are known as monobasic acids while those with two acid groups are dibasic acids. All acids with more than one acid group are in the class of polybasic acids. The simplest organic acid, formic acid, is responsible for the irritation of bee and ant stings. Vinegar is a 5% solution of acetic acid in water. The acetic acid is responsible for the characteristic sour taste. Citric acid, found in citrus fruits and used in soft drinks, is a tribasic acid with three carboxylic acid groups. The dibasic acid, adipic acid, is a major component of nylon. 

Ionization is the process of separation or dissociation of a molecule into particles of opposite electrical charge (ions). The presence and extent of ionization has a large effect on the chemical behavior of a substance. An acid or base that is extensively ionized may have markedly different solubility, sorption, toxicity, and biological characteristics than the corresponding neutral compound. Inorganic and organic acids, bases, and salts may be ionized under environmental conditions. A weak acid HA will ionize to some extent in water according to the reaction ... 

Therefore, weak organic acids and bases are readily absorbed as uncharged lipid-soluble molecules, whereas ionized compounds are absorbed only with difficulty, and nonionized toxicants with poor lipid-solubility characteristics are absorbed slowly. Lipid-soluble acid molecules can be absorbed efficiently through the gastric mucosa, but bases are not absorbed in the stomach. 

Knoll (40) in a study similar to that of Rhodes (33) demonstrated that percolation of organic acids through the soil did not influence the exchange characteristics of soil with respect to plutonium waste. However, hydroxyacetic acid removed 50% of the plutonium from soil and in the case of americium this value was raised to 100%. 

Some work [5] has been performed on the photochemical reaction between sulfur dioxide and hydrocarbons, both paraffins and olefins. In all cases, mists were found, and these mists settled out in the reaction vessels as oils with the characteristics of sulfuric acids. Because of the small amounts of materials formed, great problems arise in elucidating particular steps. When NO and 02 are added to this system, the situation is most complex. Bulfalini [3] sums up the status in this way The aerosol formed from mixtures of the lower hydrocarbons with NO and S02 is predominantly sulfuric acid, whereas the higher olefin hydrocarbons appear to produce carbonaceous aerosols also, possibly organic acids, sulfonic or sulfuric acids, nitrate-esters, etc. ... 

Organic acids can be thought of as oxidation of corresponding alcohols, since they have the characteristic -OH signature group, plus a double-bonded oxygen -COOH or... 

Many petrochemicals have been harnessed because they have two common characteristics they re simple and they re reactive. Acrylic add (AA) is the simplest organic acid that contains a double bond. Its that vinyl group again, CH2=CH-, the same one found in acrylonitrile, styrene, and vinyl chloride. Because it s an acid and because it has the double bond, it s highly reactive. It readily undergoes polymerization (reacts with itself because of the double bond) and esterification (reacts with alcohol because its an acid). 

Carbonyl. The group. —C=0, characteristically found in aldehydes, ketones and organic acids. Also the general name given to compounds containing the CO group such as nickel carbonyl, Ni(CO)4. 

Carboxyl. The group "COOH, characteristic of the organic acids, such as acetic acid, CH3COOH or adipic acid, (CH2)4 (COOH)2. 

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