Bicarbonate absorption

Figure 4 and Table 1 compare the IR spectra of ammonium bicarbonate and ammonium carbamate in fluorolube mulls. The spectrum for ammonium bicarbonate has absorptions due to the ammonium ion plus absorptions due to bicarbonate anion. The bicarbonate absorptions are similar to those observed for sodium bicarbonate but the absorptions are shifted a little. Although the ammonium and OH absorptions overlap somewhat, the OH peak at 2569-2540 cm-1 is clearly separated from the ammonium absorption region and... 

Spectra recorded at intervals after the addition of urease to an unbuffered solution of urea first show the disappearance of urea peaks at 1604 and 1490 cm and the appearance of carbamate peaks at 1441 and 1540cm along with some bicarbonate. At the end of the reaction, the urea and carbamate bands have been replaced by strong bicarbonate absorption at 1363 and 1630 cm . Figure 15.15 shows the time course of the appearance and disappearance of the individual bands in a similar experiment carbamate forms rapidly and then slowly disappears, while bicarbonate forms more slowly and approaches a maximum value. The absorption band near the 1441 band of carbamate does not disappear completely because of the appearance of a band of CO , which is in equilibrium with HCO3, at 1416 cm . ... 

Fig. 15.15. The time course of the appearance and disappearance of urea, carbamate, and bicarbonate absorption during the urease-catalyzed hydrolysis of urea. Experimental conditions were similar to those for the experiment described in Fig. 15.14, except for a urea concentration of O.lAf. (Jencks, 1963.)...

Bicarbonate Ion Concentration and Blood pH Acidification of the Urine 572 Bicarbonate Absorption Secretion of Ammonia Respiration and Blood pH... 

When levuhnic acid (CH3CCH2CH2CO2H) was hydrogenated at high pressure over a nickel catalyst at 220°C a single product C5Hg02 was isolated in 94% yield This compound lacks hydroxyl absorption in its IR spectrum and does not immediately liberate carbon dioxide on being shaken with sodium bicarbonate What is a reasonable structure for the compound" ... 

Recovery of Ammonia. The filter Hquor contains unreacted sodium chloride and substantially all the ammonia with which the brine was originally saturated. The ammonia may be fixed or free. Fixed ammonia (ammonium chloride [12125-02-97]) corresponds stoichiometrically to the precipitated sodium bicarbonate. Free ammonia includes salts such as ammonium hydroxide, bicarbonate, and carbonate, and the several possible carbon—ammonia compounds that decompose at moderate temperatures. A sulfide solution may be added to the filter Hquor for corrosion protection. The sulfide is distilled for eventual absorption by the brine in the absorber. As the filter Hquor enters the distiller, it is preheated by indirect contact with departing gases. The warmed Hquor enters the main coke, tile, or bubble cap-fiUed sections of the distiller where heat decomposes the free ammonium compounds and steam strips the ammonia and carbon dioxide from the solution. 

A.ctivated Carbonate Process. The activated carbonate process is based on absorption of CO2 by potassium carbonate (57) to give potassium bicarbonate. When the bicarbonate is heated it releases CO2, regenerating potassium carbonate. 

Potassium Carbonate Process. The potassium carbonate process is similar to the sodium carbonate process. However, as potassium bicarbonate [298-14-6] is more soluble than the corresponding sodium salt, this process permits a more efficient absorption than the other. The equipment layout is the same and the operation technique is similar. 

Ethoxycarbonyloxyethyl 6-(D-a-azidophenylacetamido)penicillinate (98 g) was prepared from sodium 6-(D-a-azidophenylacetamido]penicillinate (397 g, 1 mol), a-chlorodiethylcar-bonate (458 g, 3 mols) and sodium bicarbonate (504 g, 6 molsl. The product showed strong IR absorption at 2090 cm- and 1 780-1750 cm" showing the presence of azido group and /3-lactam and ester carbonyls. 

N-Acetylation of Kasugamycinic Acid (9a). A solution of kasugamycinic acid (225 mg.) dissolved in 10 ml. of water was treated with acetic anhydride (0.3 ml.) under cooling sodium bicarbonate was used to keep the pH 7.2 and stirring continued for 30 minutes. The reaction product was passed through Dowex 50W-X2 (H form) and the column was washed with water. The combined filtrate was subjected to lyophilization to afford 234 mg. of a crude N-acetyl derivative. Its infrared spectrum showed strong absorptions at 1740 cm-1 characteristic of oxamic acid group. The N-acetyl derivative (178 mg.) was treated with 40 ml. 

Danckwerts et al. (D6, R4, R5) recently used the absorption of COz in carbonate-bicarbonate buffer solutions containing arsenate as a catalyst in the study of absorption in packed column. The C02 undergoes a pseudo first-order reaction and the reaction rate constant is well defined. Consequently this reaction could prove to be a useful method for determining mass-transfer rates and evaluating the reliability of analytical approaches proposed for the prediction of mass transfer with simultaneous chemical reaction in gas-liquid dispersions. 

Oral administration of bicarbonate may decrease the absorption of ketoconazole. Increased blood levels of quinidine, flecainide, or sympatiiomimetics may occur when these agents are administered with bicarbonate There is an increased risk of crystalluria when bicarbonate is administered with the fluoroquinolones. Fbssible decreased effects of lithium, methotrexate, chlorpropamide, salicylates, and tetracyclines may occur when these drag s are administered with sodium bicarbonate. Sodium bicarbonate is not administered within 2 hours of enteric-coated drugs the protective enteric coating may disintegrate before the drug reaches the intestine. 

The complexation of Pu(IV) with carbonate ions is investigated by solubility measurements of 238Pu02 in neutral to alkaline solutions containing sodium carbonate and bicarbonate. The total concentration of carbonate ions and pH are varied at the constant ionic strength (I = 1.0), in which the initial pH values are adjusted by altering the ratio of carbonate to bicarbonate ions. The oxidation state of dissolved species in equilibrium solutions are determined by absorption spectrophotometry and differential pulse polarography. The most stable oxidation state of Pu in carbonate solutions is found to be Pu(IV), which is present as hydroxocarbonate or carbonate species. The formation constants of these complexes are calculated on the basis of solubility data which are determined to be a function of two variable parameters the carbonate concentration and pH. The hydrolysis reactions of Pu(IV) in the present experimental system assessed by using the literature data are taken into account for calculation of the carbonate complexation. 

In the literature (2), the possible formation of plutonyl bicarbonate complex is discussed. In order to verify whether we are dealing with bicarbonate or carbonate complexes, the Pu(IV) solutions prepared in NaHC03 and Na2C03 solutions are examined by spectrophotometry. The absorption spectra measured up to 900 nm show no visible difference for both solutions. For this reason it is believed that the Pu(IV) ion forms carbonate complexes irrespective of carbonate or bicarbonate ions present in solution. 

One of the advanced concepts for capturing CO2 is an absorption process that utilizes dry regenerable sorbents. Pure sodium bicarbonate from Dongyang Chemical Company and spray-dried sorbents were used to examine the characteristics of CO2 reaction in a flue gas environment. The chemical characteristics were investigated in a fast fluidized reactor of 0.025 m i.d., and the effects of several variables on sorbent activity, including gas velocity (1.5 to 3.5 m/s), temperature (40 to 70 °C), and solid concentration (15 to 25 kg/m /s)], were examined in a fast fluidized-bed. Spray-dried Sorb NX30 showed fast kinetics in the fluidized reactor. 

Acetylcyclohexanone. Method A. Place a mixture of 24-6 g. of cyclohexanone (regenerated from the bisulphite compound) and 61 g. (47 5 ml.) of A.R. acetic anhydride in a 500 ml. three-necked flask, fitted with an efficient sealed stirrer, a gas inlet tube reaching to within 1-2 cm. of the surface of the liquid combined with a thermometer immersed in the liquid (compare Fig. II, 7, 12, 6), and (in the third neck) a gas outlet tube leading to an alkali or water trap (Fig. II, 8, 1). Immerse the flask in a bath of Dry Ice - acetone, stir the mixture vigorously and pass commercial boron trifluoride (via an empty wash bottle and then through 95 per cent, sulphuric acid) as fast as possible (10-20 minutes) until the mixture, kept at 0-10°, is saturated (copious evolution of white fumes when the outlet tube is disconnected from the trap). Replace the Dry Ice-acetone bath by an ice bath and pass the gas in at a slower rate to ensure maximum absorption. Stir for 3 6 hours whilst allowing the ice bath to attain room temperature slowly. Pour the reaction mixture into a solution of 136 g. of hydrated sodium acetate in 250 ml. of water, reflux for 60 minutes (or until the boron fluoride complexes are hydrolysed), cool in ice and extract with three 50 ml. portions of petroleum ether, b.p. 40-60° (1), wash the combined extracts free of acid with sodium bicarbonate solution, dry over anhydrous calcium sulphate, remove the solvent by... 

X-ray diffraction studies on [TpBut,Me]Zn 2(/i,-r)1,Tj1-C03) have identified that the bridging carbonate ligand is coordinated to each zinc center in a unidentate fashion (171,172), which thereby provides additional support for the presence of a unidentate, rather than bidentate, bicarbonate ligand in [TpBut,Me]Zn(0C02H). The carbonate complex [TpBut,Me]Zn 2(/iA-7)1,T)1-C03) is also characterized by v(CO) absorptions at 1587 and 1311 cm-1 in the IR spectrum (173), and a 13C NMR signal at 8 164 ppm (in C6D6). 

Solutions that contain sodium citrate/citric acid (Shohl s solution and Bicitra) provide 1 mEq/L (1 mmol/L) each of sodium and bicarbonate. Polycitra is a sodium/potassium citrate solution that provides 2 mEq/L (2 mmol/L) of bicarbonate, but contains 1 mEq/L (1 mmol/L) each of sodium and potassium, which can promote hyperkalemia in patients with severe CKD. The citrate portion of these preparations is metabolized in the liver to bicarbonate, while the citric acid portion is metabolized to C02 and water, increasing tolerability compared to sodium bicarbonate. Sodium retention is also decreased with these preparations. However, these products are liquid preparations, which may not be palatable to some patients. Citrate can also promote aluminum toxicity by augmenting aluminum absorption in the GI tract. 

Bile is produced continuously by the liver bile salts are secreted by the hepatocytes and the water, sodium bicarbonate, and other inorganic salts are added by the cells of the bile ducts within the liver. The bile is then transported by way of the common bile duct to the duodenum. Bile facilitates fat digestion and absorption throughout the length of the small intestine. In the terminal region of the ileum, the final segment of the small intestine, the bile salts are actively reabsorbed into the blood, returned to the liver by way of the hepatic portal system, and resecreted into the bile. This recycling of the bile salts from the small intestine back to the liver is referred to as enterohepatic circulation. 

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