Bicarbonate infrared absorption

Infrared absorption in the atmosphere can have the same effect. Over the last century the concentration of carbon dioxide in the atmosphere has risen dramatically because of combustion. As a result, the atmosphere now absorbs more infrared radiation than it did in the past, and cooling into space is less efficient. A likely consequence is global warming, although a detailed calculation of the magnitude of the expected effect is far from simple. For example, while is it not difficult to estimate total CO2 emissions from combustion, most of these molecules end up in the ocean as carbonates or bicarbonates, and do not directly contribute to global warming. Nonetheless, there is broad consensus in the scientific community that carbon dioxide emissions will tend to increase the Earth s temperature over the next few decades, with environmental consequences which may be severe. 

Figure 5. Infrared absorption spectra of the acidic furnish extract fraction fractionated further by sequential extraction into aldehydic (bisulfite), hydroxyl (bicarbonate), phenolic (hydroxide), and aliphatic (neutral residual) fractions...

Carbon dioxide, C02, is a fairly small molecule with acidic properties, which has frequently been used as a probe molecule for basic surface sites and as a poison in catalytic reactions. As shown in the following, C02 adsorption onto oxide surfaces leads to a variety of surface species such as bicarbonates and carbonates that coordinate to surface metal ions in various ways. The type of the coordination influences the symmetry of these ligands so that different surface species held by distinct surface sites can be distinguished by means of their infrared absorptions (162). The characteristic infrared (and Raman) bands of C02 and possible surface species are summarized in Table VI. The wave-number range below 1000 cm"1 was usually not accessible in studies on adsorbed C02 because of the strong absorption of the oxides at lower wave numbers. 

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. 

Many investigations of the molecular structure of thin films formed by y-APS deposited onto inorganic substrates from aqueous solutions have been carried out. Ondrus and Boerio [2] used reflection-absorption infrared spectroscopy (RAIR) to determine the structure of y-APS films deposited on iron, 1100 aluminum, 2024 aluminum, and copper substrates from aqueous solutions at pH 10.4. They found that the as-formed films absorbed carbon dioxide and water vapor to form amine bicarbonate salts which were characterized by absorption bands near 1330, 1470, 1570, and 1640 cm-1. y-APS films had to be heated to temperatures above about 90°C in order to dissociate the bicarbonates, presumably to free amine, carbon dioxide, and water. Since the amine bicarbonates failed to react with epoxies, the strength of adhesive joints prepared... 

When levulinic 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 infrared spectrum and does not immediately hherate carbon dioxide on being shaken with sodium bicarbonate. What is a reasonable structure for the compound ... 

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