Determination strong acid number

Determination of strong acid number or inorganic acidity of an oil... 

Large numbers of reactions of interest to chemists only take place in strongly acidic or strongly basic media. Many, if not most, of these reactions involve proton transfer processes, and for a complete description of the reaction the acidities or basicities of the proton transfer sites have to be determined or estimated. These quantities are also of interest in their own right, for the information available from the numbers via linear free energy relationships (LFERs), and for other reasons. 

Aluminas, which were prepared from sodium aluminate and which retained about 0.1 % of sodium ions, had a large amount of weakly acid sites, and were therefore excellent dehydration catalysts. At the same time these aluminas did not isomerize cyclohexene, owing to the absence of strong acid sites, which were neutralized by the alkali metal ions. Pines and Haag (36) determined that the upper limit of the total number of acid sites, capable of dehydrating butanol, and of the number of strong acid sites, capable of isomerization of cyclohexene, was 10 X 10 and 8 X 10 sites per cm, respectively. 

Wolfrom and coworkers studied the changes that occurred in cellulose in strong hydrochloric acid under conditions that gave an ethyl mercaptan derivative of the hydroljrtic product. n-Glucose diethyl mercaptal derivatives did not appear until the hydrolysis was two-thirds complete. The extent of hydrolysis was determined by the number of sulfur groups introduced. 

The double bonds, carbonyl groups, carboxyl groups and large number of hydroxyl groups determine the physical and reaction behavior. In the case of lignosulfonates, the strongly acidic and polar sulfonic acid groups... 

Most of the older methods of fluorimetric analysis of pesticides involved hydrolysis to form fluorescent anions. Co-ral (coumaphos) [147] was hydrolyzed in alkali to the hydroxybenzopyran, which was subsequently determined by means of its fluorescence. Guthion (azinphosmethyl) was hydrolyzed to anthranilic acid for fluorimetric analysis [148,149]. A method was developed [150] for Maretin (N-hydroxynaphthalimide diethyl phosphate) in fat and meat which involved hydrolysis in 0.5 M methanolic sodium hydroxide followed by determination of the fluorescence of the liberated naphthalimide moiety. Carbaryl (1-naphthyl N-methylcarbamate) and its metabolites have been determined by a number of workers using base hydrolysis and the fluorescence of the resulting naphtholate anion [151-153]. Nanogram quantities of the naphtholate anion could be detected. Zectran (4-dimethylamino-3,5-xylyl N-methylcarbamate) has been determined by the fluorescence of its hydrolysis product [154]. The fluorescence behaviour of other carbamate insecticides in neutral and basic media has been reported [155]. Gibberellin spray used on cherries has been determined fluorimetrically after treatment with strong acid [156]. Benomyl (methyl N-[l-(butylcarbamoyl)-2-benzimidazolyl]carbamate) has been analyzed by fluorimetry after hydrolysis to 2-aminobenzimidazole [157]. 

The pH scale is a scale used to determine how acidic or basic a substance is by measuring the number of hydrogen ions in the substance. The pH scale ranges from 0 to 14. A pH of 0 is very acidic, while a very strong base would have a pH value of 14. A neutral solution (a substance that is neither acidic nor basic) would have a pH of 7. 

---