Alcohols hydrogen bonding extent

Higher alcohols become more hydrocarbon like and less water soluble 1 Octanol for example dissolves to the extent of only 1 mL m 2000 mL of water As the alkyl chain gets longer the hydrophobic effect (Section 2 17) becomes more important to the point that It more than hydrogen bonding governs the solubility of alcohols... 

Esters can participate m hydrogen bonds with substances that contain hydroxyl groups (water alcohols carboxylic acids) This confers some measure of water solubil ity on low molecular weight esters methyl acetate for example dissolves m water to the extent of 33 g/100 mL Water solubility decreases as the carbon content of the ester increases Fats and oils the glycerol esters of long chain carboxylic acids are practically insoluble m water... 

The copolymers are insoluble in water unless they are neutralized to some extent with base. They are soluble, however, in various ratios of alcohol and water, suggesting appHcations where deUvery from hydroalcohoHc solutions (149) but subsequent insolubiUty in water is desired, such as in low volatile organic compound (VOC) hair-fixative formulations or tablet coatings. Unneutralized, their Ts are higher than expected, indicating interchain hydrogen bonding (150). 

As shown in Figure 16.1, however, the presence of an oxygen atom pennits ethers to participate in hydrogen bonds to water molecules. These attractive forces cause ethers to dissolve in water to approximately the same extent as comparably constituted alcohols. Alkanes cannot engage in hydrogen bonding to water. 

Alcohols have a strong C—O stretching absorption near 1050 cm-1 and a characteristic O-H stretching absorption at 3300 to 3600 cm-1. The exact position of the O-H stretch depends on the extent of hydrogen bonding in the molecule. 

The miscibility of ethers with water resembles those of alcohols of the same molecular mass. Both ethoxyethane and butan-l-ol are miscible to almost the same extent i.e., 7.5 and 9 g per 100 mb water, respectively while pentane is essentially immiscible with water. Can you explain this olDservation This is due to the fact that Just like alcohols, oxygen of ether can also form hydrogen bonds with water molecule as shown ... 

Both reactions act to reduce hydrogen bonding within the coal structure which may have a direct positive impact on liquefaction reactivity. More indirectly, these reactions lower the concentration of OH species in coal-derived products and hence, reduce the extent of retrogressive condensation via ether bridge formation. Reducing production of THF-insoluble condensation products increases the net THF-soluble coal conversion observed during the liquefaction experiment. None of the spectra from coals pretreated with alkyl alcohols and HCl showed any significant evidence of alkylation at carbon sites in the coal. 

The presence of highly electronegative atoms which can participate in hydrogen bonding is required for the solubility of polymers in water. Such groups include amines, imines, ethers, alcohols, sulfates, carboxylic acids and associated salts, and, to a lesser extent, thiols. The water solubility is also affected by pH and the formation of charged species. Thus the copolymer derived from vinylamine and vinyl sulfonate is not soluble in water, whereas the corresponding sodium salt of this copolymer is water-soluble. 

Large anions, such as I- and CIO4, have a relatively weak tendency to accept hydrogen bonds. However, they are highly polarizable and interact to a fair extent by dispersion forces (London forces) with the molecules of aprotic solvents, which are also considerably polarizable. Thus, for large anions, the solvation energies in protic solvents (water, alcohols) and those in dipolar aprotic solvents (AN, DMF, DMSO) are not as different as in the case of small anions (Table 2.4). 

The hydroxy group is hydrophilic (water loving) because of its polarity and ability to form hydrogen bonds, so alcohols are much more soluble in water than alkanes. The smaller alcohols, containing up to three carbons, are miscible with water—that is, they mix with water in all proportions. As expected, as the alkyl group (the hydrophobic part) of the alcohol becomes larger, water solubility decreases. Thus, l-pentanol dissolves in water to the extent of 2.7 g/100 mL and 1-heptanol to the extent of 0.1 g/100 mL, whereas 1-decanol is essentially insoluble in water. 

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