Alkali recovery methods

Carbon dioxide flooding is the most promising enhanced oil-recovery method. To overcome the tendency of CO2 to bypass the smaller pores containing residual oil, one approach is to plug the larger pores by chemical precipitation. Several relatively inexpensive water-soluble salts of the earth alkali group react with CO2 to form a precipitate. 

Kosikowski (1977) described a distillation method for extracting volatile FFAs from cheese. However, individual FFAs were not quantified as the extract was titrated to a specific end point, with the amount of alkali used relating to the level of volatile acids present. Steam distillation was used successfully by Horwood and Lloyd (1980) to isolate FFAs from cheese. Formic acid was used to form FFAs from the salts obtained after distillation of the acids from cheese into alkali. This method was also used by Parliament et al. (1982) who extracted SCFFAs from an acidified aqueous suspension of cheese. Contarini et al. (1988) evaluated steam distillation for the extraction of volatile FFAs from Grana cheese and obtained very good recoveries. Kilcawley et al. (2001) also used steam distillation to isolate C2 o, C3 0 and C4 o from enzyme-modified cheese. 

Both the direct and the alcoholic alkali fusion methods gave recoveries of 90% or better with phenyl-containing silicones, the results obtained by the alcoholic alkali modification being generally higher. 

To develop improved alkali-surfactant flooding methods, several different injection strategies were tested for recovering heavy oils. Oil recovery was compared for four different injection strategies [641] ... 

Davidow (19), of the Food and Drug Administration, has described a colorimetric method applicable to technical chlordan. The method is based on the observation that when technical chlordan is heated with a mixture of diethanolamine and methanolic potassium hydroxide, a purple color is produced. When known amounts of this insecticide were added to cabbage, pears, and fresh and rancid rat fat, recoveries of 74 to 104% of the insecticide were obtained. However, because two crystalline isomers of chlordan isolated from the technical product do not give a colored reaction product with the reagent, further investigation of the method is being made. The red color obtained when technical chlordan is heated with pyridine, alcoholic alkali, and ethylene glycol monoethyl ether, as described by Ard (2), likewise fails with the crystalline isomers of this insecticide. 

The final analytical method for the simultaneous determination of A9-THC and its metabolites consists of the following sequence the cannabinoids are extracted from plasma with toluene they are then back extracted from toluene into Claisen s alkali the Claisen s alkali is diluted with water, tetrahexyl ammonium hydroxide is added and the alkaline solution is extracted with methylene chloride containing ethyl iodide. The overall recoveries were 45% for A9-THC and 83% for 11-hydroxy-A9-THC. External standards (l-0-ethyl-A9-THC and l-0-ethyl-ll-hydroxy-A9-THC) were added to the methylene chloride phase followed by a small amount of Florosil, which absorbed the tetra-hexylammonium hydroxide and tetrahexylammonium iodide. The methylene chloride was decanted and evaporated. 

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