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CHM 324 Final
Organic Chemistry II Lab
18
Chemistry
04/26/2011

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Term
purpose of E12: alcohols as nucleophiles
Definition
produce an ester through nucleophilic substitution
Term
E12: alcohols as nucleophiles overall reaction
Definition
1-butanol + acetic acid = butyl acetate
Term
E12: which layer is on bottom
Definition
water b/c butyl acetate is less dense
Term
IR range for alcohol
Definition
3200-3650
Term
IR range for carboxylic acid
Definition
2400-3400 & 1700-1725
Term
IR range for C-O ester
Definition
1000-1300 & 1730-1750
Term
E12: why alcohols can be nucleophilic
Definition
- lone pairs on oxygen
- attack electron-deficient atom (usually C in C=O bond)
Term
E12: when alcohols react with carbonyl groups of carboxylic acids...
Definition
...a nucleophilic substitution occurs, in which the alcohol replaces the OH of the carboxylic acid, producing an ester
Term
E12: two strategies for overcoming limitations in equilibria in synthesis
Definition
- use one reactant in excess
- remove product as it is produced
Term
E12: why does the acid remain in the flask
Definition
it isn't volatile
Term
E12: why does the acid remain in the flask
Definition
it isn't volatile
Term
potassium permanganate test
Definition
positive = stays purple, no C=C
negative = changes to brown, precipitate, C=C
Term
Williamson synthesis goes through a _____ reaction
Definition
Sn2 between a good nucleophile and a suitably alkyl halide
Term
Williamson ether: which is nucleophile and which is alkyl halide?
Definition
phenoxide ion (ArO-) is nucleophile
methyl iodide is alkyl halide
Term
role of PTC in Williamson ether synthesis
Definition
- to transfer the phenoxide ion from the aqueous phase into the organic phase where the Sn2 reaction occurs
- after the first NaOH solution is added, two layers are formed, with CH3I on bottom and NaOH on top
o two layers are not miscible, so the ArO- will not come into contact with the CH3I, meaning the reaction won’t happen
o the PTC has dual solubility
• soluble in organic layer because of 4 butyl groups
• soluble in aqueous layer because of ionic character
Term
purpose of Williamson ether synthesis
Definition
synthesize an ether, using an Sn2 reaction, and then purify the product using chromatography column with silica gel. The reactant is 4-ethylphenol and tetrabutylammonium bromide and methyl iodide catalyst and react with it, respectively, forming methyl p-ethylphenyl ether. Then characterize by IR.
Term
column chromatography
Definition
- based on polarities
- silica gel is polar & keeps polar molecules
- nonpolar molecules pass through
Term
in Williamson ether synthesis, name 4 potential nucleophiles
Definition
ArO-, Br-, I-, OH-