Potassium carbonate solutions

Benfield process Removal of carbon dioxide from fuel gases, such as those obtained by gasifying coal in the Lurgi process, by countercurrent scrubbing of the gases by hot potassium carbonate solution. 

Catacarb process An extraction process used to remove carbon dioxide from process gases by scrubbing the hot gases with potassium carbonate solution containing additives which increase the hydration rate of the gas in the solution. The Vetrocoke process is similar. See Benfield process. 

In one process the carbon dioxide is removed using potassium carbonate solution, potassium hydrogencarbonate being produced ... 

Some neutral compounds (e.g., methyl alcohol) cannot be salted out with potassium carbonate distillation of the saturated aqueous potassium carbonate solution frequently yields the organic compound in a comparatively pure state, or at least in sufllciently concentrated a form to enable certain derivatives to be prepared. 

An alternative method, which does not involve the formation of bromate, is treatment of iron turnings with a 35 wt % aqueous solution of bromine. Ferrosoferric bromide, Fe3Brg T6H2O, forms and can be crystallized. The iron bromide is heated to a boil with a slight excess of 15 wt % potassium carbonate solution. 

FIG. 23-27 CO, in potassium carbonate solutions (<2) equilibrium in 20% solution, (h) mass-transfer coefficients in 40% solutions. (Data cited hy Kohl and Riesenfeld, Gas Purification, Gulf Fuhlishing, 1985.)... 

Physical solvent type Fluor solvents (propylene carbonate example), Selexol Physical/chemical type Sulfinol Carbonate type Potassium carbonate Solution batch type Lo-Cat, Chemsweet Bed batch type Iron Sponge, Mol Sieve... 

Three major sources in the kraft process are responsible for the majority of the H2S emissions. These involve the gaseous waste streams leaving the recovery furnace, the evaporator and the air stripper, respectively denoted by R), R2 and R3. Stream data for the gaseous wastes are summarized in Table 8.8. Several candidate MSAs are screened. These include three process MSAs and three external MSAs. The process MSAs are the white, the green and the black liquors (referred to as Si, S2 and S3, respectively). The external MSAs include diethanolamine (DBA), S4. activated carbon, Sj, and 30 wt% hot potassium carbonate solution, S6. Stream data for the MSAs is summarized in Table 8.9. Syndiesize a MOC REAMEN that can accomplish the desulfurization task for the three waste streams. 

The acid-rich potassium carbonate solution from the bottom of the absorber is flashed to a flash drum, where much of the acid gas is removed. The solution then proceeds to the stripping column, which operates at approximately 245 °F and near-atmospheric pressure. The low pressure, combined with a small amount of heat input, drives off the remaining acid gases. The lean potassium carbonate from the stripper is pumped back to the absorber. The lean solution may or may not be cooled slightly before entering the absorber. The heat of reaction from the absorption of the acid gases causes a slight temperature rise in the absorber. 

The hot potassium carbonate solutions are extremely corrosive. All carbon steel must be stress-relieved to limit corrosion. A variety of corrosion inhibitors are available to decrease corrosion. 

After the calculated amount of hydrogen had been absorbed, the catalyst was filtered off, the solution was concentrated in vacuo, and the residual syrup was dissolved in ice water. Benzene was added and the mixture was made alkaline with an excess of concentrated ice cold potassium carbonate solution. The temperature was kept low by continuous addition of ice, and the benzene layer was separated and dried with sodium sulfate. The dried benzene solution was concentrated in vacuo and the residual oil was distil led in vacuo. BP 30 mm = 175°-1 B2°C,... 

The filtrate is treated with excess hydrochloric acid and evaporated to obtain a pale yellow oil. Five grams of the oil thus obtained is treated with 15 cc of saturated potassium carbonate solution and the mixture extracted with 50 cc of ether, then with 30 cc of ethyl acetate and finally with two 30 cc portions of ethanol. Evaporation of the solvent from the extract gives the following quantities of the desired 1-phenyl-2-aminopropane-1,3-diol 0.5 g, 1.0 g and 3.1 g. 

A mixture of 10.3 g of thiophene-20 -methylacetic acid [prepared by process of Bercot-Vat-teroni, et al.. Bull. Soc. Chim. (1961) pp. 1820-211, 11.10 g of benzoyl chloride and a suspension of 23.73 g of aluminum chloride in 110 cc of chloroform was allowed to stand for 15 minutes and was then poured into a mixture of ice and hydrochloric acid. The chloroform phase was extracted with a 10% aqueous potassium carbonate solution and the aqueous alkaline phase was acidified with N hydrochloric acid and was then extracted with ether. The ether was evaporated off and the residue was crystallized from carbon tetrachloride to obtain a 54% yield of 5-benzoyl-thiophene-20 -methylacetic acid melting at 83°C to 85°C. The... 

Benzyl cyanide is first reacted with 2-butylbromide in the presence of sodium amide to give 2-phenyl-3-methylvaleronitrile which is hydrolyzed by sulfuric acid to give 3-methyl-2-phenyl-pentanoic acid. 24 g of 2-phenyl-3-methyl-pentanoic acid are heated for one hour at 175° to 185°C with 30 g of 2-diethylaminoethanol and 0.5 g of sodium methylate. The excess diethyl-aminoethanol is removed in vacuo, the residue is dissolved in 300 cc of 2 N-acetic acid, the acid solution is shaken with ether and made alkaline with concentrated potassium carbonate solution and ice. The ether solution Is washed with water, dried with sodium sulfate and evaporated. The residue is distilled under high vacuum, yielding 20 to 21 g of the basic ester (60% of the theoretical) is obtained, the ester boiling at 98° to 100°C at a pressure of 0.03 mm. The hydrochloride of the ester melts at 112° to 113°C and the methobromide at 100° to 101°C. 

Benfield process aqueous potassium carbonate blocking of pores of methanation catalyst by evaporation of potassium carbonate solution... 

Take the physical properties of the dilute potassium carbonate solution to be the same as those for water. 

II. Basic data for CO2 removal using hot potassium carbonate solutions... 

After the mixture has been cooled to 15-20° it is transferred to a 2-1. separatory funnel and the crude product is washed first with two 1-1. portions of water cooled to 5-15°, then with 500 ml. of cold 10% potassium carbonate solution, and finally with 500 ml. of cold water. The product is the lower layer in all the washings. After the addition of 200 ml. of ether, the solution is given a preliminary drying by being allowed to stand over 10 g. of anhydrous potassium carbonate, with frequent shaking, for 1 hour. The lower aqueous layer which forms is separated, and the ether solution is again dried over 20 g. of potassium carbonate for 8-10 hours (Notes 3 and 4). 

The H2 is separated from C02 and purified at the final stage of the process. Older variations of the SMR process (Figure 2.5a) used solvents to remove the acid gas (C02) from the gaseous stream after WGS reactors. Solvents commercially used for C02 removal in the gas separation unit include monoethanolamine (most preferred and widely used solvent), water, ammonia solutions, potassium carbonate solutions, and methanol. This operation allows the reduction of C02 concentration in the process gas to about 100 ppm. The remaining... 

Carbosolvan One of the several processes for absorbing carbon dioxide from gases, using hot potassium carbonate solution. See also Benfield, Carsol, CATACARB, Giammarco-Vetrocoke, Hi-Pure. 

CATACARB [Catalyzed removal of carbon dioxide] A process for removing carbon dioxide and hydrogen sulfide from gas streams by absorption in hot potassium carbonate solution containing a proprietary catalyst. Developed and licensed by Eickmeyer and Associates, KS, based on work at the U.S. Bureau of Mines in the 1950s. More than a hundred plants were operating in 1997. See also Benfield, Carsol, Hi-pure, Giammarco-Vetrocoke. 

CONOSOX A complex flue-gas desulfurization process using potassium carbonate solution as the wet scrubbing medium. The product potassium bisulfite is converted to potassium thiosulfate and then reduced with carbon monoxide to potassium carbonate for re-use. The sulfur is recovered as hydrogen sulfide, which is converted to elemental sulfur by the Claus process. Developed by the Conoco Coal Development Company and piloted in 1986. 

HiPure A variation on the Benfield process, using two stages of scrubbing by hot potassium carbonate solution in order to reduce the carbon dioxide contents of gases to very low levels. See also Carsol, CATACARB, Giammarco-Vetrocoke. 

The work-up was done by dropwise addition of ice-cold water (50 mL caution gas evolution ). The reaction mixture was diluted with dichloromethane (lOOmL) and washed with saturated potassium carbonate solution (2 x 50 mL) and brine (2 x 50 mL). The organic layer was dried over magnesium sulfate, filtrated and concentrated using a rotatory evaporator. 

The resulting solution is cooled to 0° and decomposed by careful addition of 500 ml. of 102V hydrochloric acid. The mixture is transferred to a separatory funnel, the aqueous phase is separated, and the toluene layer is extracted with two 250-ml. portions of 102V hydrochloric acid. The aqueous extracts are combined and heated under reflux for 15 hours to effect decarboxylation. The hot, dark-colored solution is treated with 10 g. of activated charcoal, filtered, and evaporated to dryness under reduced pressure. The residue is washed into a separatory funnel with 300 ml. of water. The solution is treated with saturated aqueous potassium carbonate solution until it is alkaline to litmus the carbonate solution must be added very carefully to prevent excessive foaming. Solid potassium carbonate is added until a thin slurry is obtained, and the slurry is extracted with four 400-ml. portions of ether. The combined ether extracts are dried for at least 60 minutes over calcined potassium carbonate and then filtered. 

Chau and Terry [146] reported the formation of penta-fluorobenzyl derivatives of ten herbicidal acids including 4-chloro-2-methyl-phenoxy acetic acid [145]. They found that 5h was an optimum reaction time at room temperature with pentafluorobenzyl bromide in the presence of potassium carbonate solution. Agemian and Chau [147] studied the residue analysis of 4-chloro-2-methyl phenoxy acetic acid and 4-chloro-2-methyl phenoxy butyric acid from water samples by making the pentafluorobenzyl derivatives. Bromination [148], nitrification [149] and esterification with halogenated alcohol [145] have also been used to study the residue analysis of 4-chloro-2-methyl phenoxy acetic acid and 4-chloro-2-methyl phenoxybutyric acid. Recently pentafluorobenzyl derivatives of phenols and carboxylic acids were prepared for detection by electron capture at very low levels [150, 151]. Pentafluorobenzyl bromide has also been used for the analytical determination of organophosphorus pesticides [152],... 

The potassium carbonate solution is added all at once. The carbon dioxide which is evolved does not interfere with the extraction of the ester. 

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