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Characteristics of hydroxyl groups
1) hybridization and bond angle
2) how does the bond angle compare to the bond angle of water
The O-H bond lengths are about the same in water and methanol, but the C-O is __, reflecting the __ of carbon compared to hydrogen.
- 1) sp3/ 108.9
- 2) it is larger
- 3) because the methyl group is much larger than a hydrogen atom
- larger covalent radius
One way of organizing the alcohol family is to classify each alcohol according to the type of __: the one bonded to the -OH group. If this carbon atom is __(bonded to one other carbon atom), the compound is a __.
- carbinol carbon atom
- primary alcohol
A __ has the -OH group attached to the __ carbon atom, and a __ has it bonded to a __ carbon.
Compounds with a hydroxyl group bonded directly to an aromatic ring are called __, which have many properties similar to those of alcohols, while other properties derive from their __.
- aromatic character
1) carries the __ suffix, together with a __ to give the hydroxyl's location.
2) What is the first rule for naming.
- 1) ol, number
- 2) find the longest carbon chain bearing the -OH group
The alcohol functional group takes __ over __ and __, so the chain is numbered in order to give the lowest possible number to the carbon atom bonded to the __ group
- triple bonds
The -OH functional group is named as a __ when it appears on a structure with a higher-priority functional group or when the structure is too difficult to name as a simple alcohol..
Alcohols with two -OH groups are called __ or __. They are named like other alcohols except that the suffix __ is used and two numbers are needed.
The term glycol generally means __, or __, with its two hydroxyl groups on adjacent carbon atoms. __ are usually synthesized by the hydroxylation of alkenes, using peroxyacids, osmium tetroxide, or potassium permanganate.
- vicinal diol
Because the phenol structure involves a benzene ring, the terms __ (1,2-disubbed), __ (1,3-disubbed), and __ (1,4-disubbed) are often used in the common names.
The methylphenols are called __, while the names of the __ are based on their historical uses and sources rather than their structures.
Most of the common alcohols, up to about 11 or 12 carbons, are __ at room temp.
True or False: Lower molecular weight alcohols are liquids.
Such large difficerences in BPs of ethyl alcohol (78) and propane alochol (-42) suggests that __ are attracted to each other much more strongly than __ molecules. Two important intermolecular forces are responsible: _ and __.
__ is the major intermolecular attraction responsible for ethanol's hight BP. The hydroxyl hydrogen of ethanol is strongly __ by its bond to oxygen and it forms a __ with a pair of nonbonding electrons from the oxygen atom of another alocohol molecule.
- h bonding
- hydrogen bond
Ethers have __ bonded to their oxygen atoms, so they have no O-H hydrogen atoms to form hydrogen bonds. __ have a strength of about 21 kJ per mole: weaker than typical __ of 300-500 kJ, but much stronger than __.
two alkyl groups
__ also contribute to the relatively __ of alcohols and ethers. The polarized C-O and H-O bonds and the nonbonding electrons add to produce a __ of 1.69 D in ethanol, compared with a __ of only 0.08 D in propane. In liquid ethanol, the positive and negative ends of these dipoles align to produce attractive interactions.
- dipole-dipole attractions
- high BPs
- dipole moment x2
__ are clearly much stronger intermolecular attractions than __.
Walter and alcohols have similar properties because they all contain __ that can form H bonds. Alcohols form hydrogen bonds with water, and several of the lower-MW alcohols are __ (soluble in any proportions) with water.
Similarly, alcohols are much better __ than __ for polar substances. Significant amounts of ionic compounds such as NaCl can dissolve in some of the lower alcohols. We call the hydroxyl group __, meaning "water loving" because of its affinity for water and other polar substances
The alcohol's alkyl group is called __ because it acts like an alkane: it disrupts the network of hydrogen bonds nad dipole dipole attractions of a polar solvent such as water. The alkyl group makes the alcohol less __, yet it lends solubility in nonpolar organic solvents. As a result, most alcohols are miscible with a wide range of nonpolar organic solvents.
True or False: The water solubility increases as the alkyl group becomes larger.
False: decreases as the alkyl group becomes larger
- alcohols with one, two, or three carbon alkyl groups are miscible
- a four carbon is large enough that some isomers are not miscible, but tert butyl alcohol is miscible.
a hydroxyl gorup can carry about 4 carbon atoms into water
Like the hydroxyl proton of water, the hydroxyl proton of an alcohol is __. A strong base can remove the hydroxyl proton to give an __.
- weakly acidic
- alkoxide ion
The acidities of alcohols vary widely, from alcohols that are about as acidic as water to some that are much less acidic. The __ of an alcohol is defined by the __.
- acid-dissociation constant, Ka
The __ constants for alcohols vary according to their structure, from about 10^-16 for __down to about 10^-18 for most __.
Explain the trend in acidity.
the acidity decreases as the substitution on the alkyl group increases, because a more highly substituted alkyl group inhibits solvation of the alkoxide ion, decreasing the stability of the alkoxide ion and driving the dissociation equilibrium toward the left
- acid-dissociation constants
- tertiary alcohols
__ are strong nucleophiles and strong bases. When an __ is needed in a synthesis, it is often formed by th reaction of __ or __ with the alcohol. This is an __, with the metal being __ and the H ion __ form hydrogen gas. __ bubbles out of the solution, leaving the sodium or potassium salt of the alkoxide ion.
- alkoxide ions x2
- potassium metal
The more acidic alcohols, like methanol and ethanol, react rapidly with sodium to form __ and __. __ react more slowly. __ react very slowly with sodium. __ is often used with secondary and tertiary alcohols because it is __, and the reaction can be completed in convenient amount of time.
- sodium methoxide
- sodium ethoxide
- secondary alcohols
- tertiary alcohols
- more reactive than sodium
Some alcohols react slowly with both __ and __ In these cases, a useful alternative is __, often is tetrahydrofuran (THF) solution. __ reacts quickly to form the __, even with different compounds.
- sodium hydride x2
True or False: Phenols have the same acidity as cyclohexanols.
- Phenols are nearly 100 million times more acidic than cyclohexanol
Cyclohexanol is a typical __, with a typical acid-dissociation constant for an __. There must be something special about phenol that makes it unusually __. The __ is more stable than a typical __ because the negative charge is not confined to the oxygen atom but is delocalized over the __ and __ of the ring.
- secondary alcohol
- phenoxide ion
- three carbon atoms
A large part of the negative charge in the __ still resides on the __, since it is the most __ of the four atoms sharing the charge. But the ability to spread the negative charge over four atoms rather than concentrating it on just one atom produces a more stable ion. The reaction of phenol with __ is __.
- resonance hybrid
- oxygen atom
- sodium hydroxide
__ are prepared simply by adding hte __ to an aqueous solution of __ or __. There is no need to use __ or __. __ was once called __ because of its ability to __ common bases.
- phenoxide anions
- sodium hydroxide
- potassium hydroxide
- potassium metal
- carbolic acid