The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
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The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
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Unbranched alkanes are compounds containing only carbon and hydrogen atoms in continuous chains. Branched-chain alkanes, on the other hand, contain short carbon chains (known as alkyl groups) attached to longer carbon skeletons. The convention is to name the alkyl group using the Greek word for the number of carbon atoms present. Thus, the alkyl group with five carbons is referred to as a pentyl group, which is the name obtained by dropping the -ane suffix from the five-carbon unbranched chain (pentane, having the structural formula CH3CH2CH2CH2CH3), and substituting a -yl ending.
The pentyl group (also known as an amyl group), therefore, corresponds to the five-carbon aliphatic group C5H11. This group has eight possible constitutional as isomeric arrangements (excluding optical isomers); the structure of the simplest of these, i.e., the n-pentyl group, is CH3CH2CH2CH2CH2-(where the n- prefix is an abbreviation for "normal." Compounds containing pentyl groups usually occur as as mixtures of several isomers. Because the as boiling points of these compounds are close and their other properties are similar, the expense and difficulty of separating them is seldom warranted. Amyl compounds, i.e., those containing pentyl groups, exist in fusel oils; they can also be formed from petroleum pentanes.
The amyl alcohols (C5H11OH), which are among the simplest of compounds containing pentyl groups, have the following eight isomeric structures (excluding optical isomers): n-amyl alcohol, primary or CH3(CH2)4OH; 2-meth yl-1-butanol or CH3CH2CH(CH3 )CH2OH; isoamyl alcohol, primary or (CH3)2CHCH2C H2OH; 2-pentanol or CH3CH2CH2CH2OCH3, 3-pentanol or CH3CH2CHOHCH 2CH3; tert-amyl alcohol or (CH3)2C(OH)CH2CH3; sec-isoamyl alcohol or CH3CHOHCH(CH3)2; and 2,2-dimethyl-1-propanol or (CH3)3CCH2OH. The isomers n-amyl alcohol, primary; 2-pentanol; and 3-pentanol exist as linear, unbranched chains of carbon and hydrogen atoms, whereas the isomers 2 methyl-1-butanol;isoamyl alcohol, primary; tert-amyl alcohol; sec-isoamyl alcohol;and 2,2 dimethyl-1 propanol are branched compounds.The isomers 2-methyl-1-butanol; 2-pentanol; and sec-isoamyl alcohol are chiral and exhibit optical activity.