Alcohols intermolecular bonding

When an aqueous solution of the A-fraction is cooled in contact with butyl alcohol, it satisfies its associative tendencies through the formation of an alcoholate. Since butyl alcohol is probably adsorbed via its hydroxyl group, the alcoholate then presents a hydrophobic surface to the medium and precipitates from solution." The crystalline precipitate can be washed with cold water saturated with butyl alcohol, since this will not dissolve alcohol from the alcoholate and therefore does not disturb the crystal lattice. When the crystals are dried in the absence of water, the crystal structure is frozen without the establishment of intermolecular bonding. Consequently, the product can be dissolved in hot water. With cold water, the molecules immediately associate to give an insoluble gel. 

Type 11 gels are heat-reversible, being held together by intermolecular bonds such as hydrogen bonds. Sometimes bridging by additive molecules can take place in these type 11 systems. Polyfvinyl alcohol) solutions gel on... 

Free OH Primary alcohols Secondary alcohols Tertiary alcohols Phenols Oximes Peroxide OH Bonded OH Intermolecular bonds... 

In aqueous solution intermolecular association between carboxylic acid molecules IS replaced by hydrogen bonding to water The solubility properties of carboxylic acids are similar to those of alcohols Carboxylic acids of four carbon atoms or fewer are mis cible with water m all proportions... 

The hydroxyl groups in poly(vinyl alcohol) contribute to strong hydrogen bonding both intra- and intermolecularly, which reduces solubiUty in water. The presence of the residual acetate groups in partially hydrolyzed poly(vinyl alcohol) weakens these hydrogen bonds and allow solubiUty at lower temperatures. 

Amines, like ammonia NH3, are polar compounds and, except for tertiary amines, form intermolecular hydrogen bonds leading to higher boiling points than non-polar compounds of the same molecular weight, but lower boiling points than alcohols or acids. The smaller molecules, containing up to about six carbon atoms, dissolve in water. Aliphatic amines are similar in basicity to ammonia and form water-soluble salts with acids ... 

In these compounds, as in water, the principal intermolecular forces are hydrogen bonds. When a substance like methyl alcohol dissolves in water, it forms hydrogen bonds with H20 molecules. These hydrogen bonds, joining a CH3OH molecule to an H20 molecule, are about as strong as those in the pure substances. 

The formulas of alcohols are derived from that of water by replacing one of the hydrogen atoms with an organic group. Like water, they form intermolecular hydrogen bonds. 

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