370 ALCOHOLS, DIOLS, AND THIOLS (c) Alternatively, 1-butanol may be prepared by the reaction of a Grignard reagent with ethylene CHaCHLCH,CH,OH CHa CH2+ H,C--CH2 In this case, ethylmagnesium bromide would be used CHaCH2Br diethyl ether CH CH2MgBr Ethyl bromide Ethylmagnesium bromide I. diethyl ether CH3 CH2 MgBr H2C CH 2.HO+ CHCH,CH, CH,OH Ethylene oxide 1-Butanol (d) Primary alcohols may be prepared by reduction of the carboxylic acid having the same num- ber of carbons. Among the reagents we have discussed, the only one that is effective in the reduction of carboxylic acids is lithium aluminum hydride. The four-carbon carboxylic acid butanoic acid is the proper substrate CH..CH 1. LiAlHy diethyl ether 2.H,O CHCH,CH,CH,OH (e) Reduction of esters can be accomplished using lithium aluminum hydride. The correct methyl ester is methyl butanoate L LiAlH4 CH3CH2CH,COCH3 2.H-O CH3CH,CH, CH,OH CH,OH Methyl butanoate Methanol Cf) A butyl ester such as butyl acetate may be reduced with lithium aluminum hydride to prepare CHI COCH,CH2CH2..O CH CH_CH,CH2OH CH3CH2OH Butyl acetate 1-Butanol Ethanol (g) Because 1-butanol is a primary alcohol having four carbons, butanal must be the aldehyde that is hydrogenated. Suitable catalysts are nickel, palladium, platinum, and ruthenium CH. CHCHCH CHaCH,CH,CH,OH h) Sodium borohydride reduces aldehydes and ketones efficiently. It does not reduce carboxylic CHaCHaCHLCH water. ethan CHaCH,,CHLOH 1-Butanol Back Forward Main Menu TOC Study Guide Toc Student OLC MHHE Website(c) Alternatively, 1-butanol may be prepared by the reaction of a Grignard reagent with ethylene oxide. In this case, ethylmagnesium bromide would be used. (d) Primary alcohols may be prepared by reduction of the carboxylic acid having the same num￾ber of carbons. Among the reagents we have discussed, the only one that is effective in the reduction of carboxylic acids is lithium aluminum hydride. The four-carbon carboxylic acid butanoic acid is the proper substrate. (e) Reduction of esters can be accomplished using lithium aluminum hydride. The correct methyl ester is methyl butanoate. (f ) A butyl ester such as butyl acetate may be reduced with lithium aluminum hydride to prepare 1-butanol. (g) Because 1-butanol is a primary alcohol having four carbons, butanal must be the aldehyde that is hydrogenated. Suitable catalysts are nickel, palladium, platinum, and ruthenium. (h) Sodium borohydride reduces aldehydes and ketones efficiently. It does not reduce carboxylic acids, and its reaction with esters is too slow to be of synthetic value. CH3CH2CH2CH2OH Butanal 1-Butanol CH3CH2CH2CH O NaBH4 water, ethanol, or methanol H2, Pt CH3CH2CH2CH2OH Butanal 1-Butanol CH3CH2CH2CH O 1. LiAlH4 2. H2O CH3CH2CH2CH2OH CH3CH2OH Butyl acetate 1-Butanol Ethanol CH3COCH2CH2CH2CH3 O 1. LiAlH4 2. H2O CH3CH2CH2COCH3 CH3CH2CH2CH2OH CH3OH Methyl butanoate 1-Butanol Methanol O 1. LiAlH4, diethyl ether 2. H2O CH3CH2CH2COH CH3CH2CH2CH2OH Butanoic acid 1-Butanol O CH3CH2MgBr CH3CH2CH2CH2OH Ethylene oxide 1-Butanol 1. diethyl ether 2. H3O H2C CH2 O Mg diethyl ether CH3CH2Br CH3CH2MgBr Ethyl bromide Ethylmagnesium bromide CH3CH2CH2CH2OH CH3CH2 H2C CH2 O 370 ALCOHOLS, DIOLS, AND THIOLS Back Forward Main Menu TOC Study Guide TOC Student OLC MHHE Website