Alkali recovery

Silica interferes with the alkali recovery cycle in various forms of alkaline pulping and is in consequence the major reason for the neglect of many readily available forms of lignocellulose, particularly cereal straw, for papermaking. 

Diffusion dialysis Acid or alkali recovery from waste... 

Recovery of acid or alkali from waste acid or alkali Recovery or removal of trace ions Concentration or desalination of electrolyte Separation of electrolyte from non-electrolyte Dehydration of water-miscible organic solvent Removal of acidic gases, separation between olefins and alkanes... 

In a 500 ml. wide-mouthed reagent bottle place a cold solution of 25 g. of sodium hydroxide in 250 ml. of water and 200 ml. of alcohol (1) equip the bottle with a mechanical stirrer and surround it with a bath of water. Maintain the temperature of the solution at 20-25°, stir vigorously and add one-half of a previously prepared mixture of 26-5 g. (25 -5 ml.) of purebenzaldehyde (Section IV,115) and 7 -3 g. (9-3 ml.) of A.R. acetone. A flocculent precipitate forms in 2-3 minutes. After 15 minutes add the remainder of the benzaldehyde - acetone mixture. Continue the stirring for a further 30 minutes. Filter at the pump and wash with cold water to eliminate the alkali as completely as possible. Dry the solid at room temperature upon filter paper to constant weight 27 g. of crude dibenzalacetone, m.p. 105-107°, are obtained. Recrystallise from hot ethyl acetate (2-5 ml. per gram) or from hot rectified spirit. The recovery of pure dibenzalacetone, m.p. 112°, is about 80 per cent. 

Chlorine Plant Auxiliaries. Flow diagrams for the three electrolytic chlor—alkali processes are given in Figures 28 and 29. Although they differ somewhat in operation, auxiUary processes such as brine purification and chlorine recovery are common to each. 

Sulfates or sulfonates Alkali metal salts of sulfated alcohols, sulfonic acid salts alkyl-aryl sulfonates sodium laiiryl sulfate Nonaqiieoiis systems mixed aqueous and nonaqiieoiis systems oil-well drilling muds spent H3SO4 recovery deep-fat frying... 

For recovery of tetrahydrofuran, the condensate from the cooling traps and the low-boiling material from the fractionations are combined, cooled in an ice bath, and treated carefully with 15-20 cc. of 40 per cent alkali. The upper layer is separated, dried with a little calcium chloride, and distilled. The recovered tetrahydrofuran, b.p. 64-67°, weighs 20-22 g. (17-19 per cent of the original material). The residue (12-14 g-) remaining after disdllation of the tetrahydrofuran distils at 43-45°/io mm. and is tetramethylene dichloride. 

However, complete hydrolysis of carotenoid esters sometimes is not achieved in 1 to 3 hr. The saponification degree can be verified easily by the presence of carotenol ester peaks eluting later than the peaks of P-carotene on reversed phase columns. Retinol palmitate, added as an internal standard to orange juice, also serves to indicate whether saponification is complete, since it is converted to retinol which elutes at lower retention time. The mixture is subsequently washed with water until free of alkali in a separatory funnel. Other more polar solvents such as CH2CI2 or EtOAc, and diethyl ether alone or mixtured with petroleum ether can be used to increase the recovery of polar xanthophylls from the water phase. 

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] ... 

Alkali/polymer flooding Alkali/surfactant/polymer flooding Alkaline-assisted thermal oil recovery Alkaline steamflooding Polymer-assisted surfactant flooding Water-alternating gas technology... 

The effectiveness of alkaline additives tends to increase with increasing pH. However, for most reservoirs, the reaction of the alkaline additives with minerals is a serious problem for strong alkalis, and a flood needs to be operated at the lowest effective pH, approximately 10. The ideal process by which alkaline agents reduce losses of surfactants and polymers in oil recovery by chemical injection has been detailed in the literature [1126]. 

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. 

M. R. Islam and A. Chakma. Mathematical modelling of enhanced oil recovery by alkali solutions in the presence of cosurfactant and polymer. / Plefro/ Sci Eng, 5(2) 105-126, February 1991. 

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 alkali-soluble protein of the peel of lemons treated with hydrogen sulfide, sulfur dioxide, and sulfuric acid contained radioactive sulfur, but the fruit treated with hydrogen sulfide had a significantly lower per cent specific activity in the alkali-soluble protein fraction than did the sulfur dioxide or sulfuric acid treated fruits (Table VII). These results suggest that sulfur dioxide and sulfuric acid react with protein more directly, while hydrogen sulfide perhaps must be oxidized first, as indicated in Table III. It also appears (from Table VII) that the alkali-soluble protein may have been dismuted as the amounts isolated were less in both the hydrogen sulfide and sulfur dioxide treated fruit than in the incubated or nonincubated controls. Other evidence of dismutation has been obtained in experiments where incubation at 60° C. was accompanied by the production of free ammonia (18), and the recovery of free ammonia and six amino acids in the exudates of incubated and sulfur-dusted fruits (18). 

The weight percentage breakdown of fractions and subfractions obtained from fractionation of both the crude oil and shale oil samples are shown in Figure 3 and 4, respectively. The percentage recoveries of Fraction HI from the crude oU and shale oil samples were 16.5% and 24.1%, respectively. To investigate the interfacial activity of these subfractions upon reaction with alkali, IFT measurements were carried out with a 1% solution of each fraction in toluene against aqueous... 

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