Ch 11 - Reactions of Alcohols - 1 1 Reactions of AlcohoLs A...

Ch 11 - Reactions of Alcohols
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Unformatted text preview: 1 1 Reactions of AlcohoLs A lcohols are important organic compounds because the hydroxyl gRoup is easily converted to almost any other functional group. In Chapter 10, we studied reac- tions that form aLcohoLs In this chapter, we seek to uNderstand how aLcohoLs react and wHch reagents are best for converting them to other kinds of compounds Table 111 summazes the types of reactions aLcohoLs undeRgo and the products that resuLt TABLE - Types of Reactions of Alcohols R - OH type of reaction PROduCT 0 dehydration esteRifcatIoN II - OH alkees - OH O-C-' esteRs oxIdation OH KeToes, aLDeyDes aIDs OH tosyato Os substITutio Tosyate esteRs - OH - OH 11-1 Oxidation States of AlcohoLs and ReLated FunctionaL Groups 460 X haIdes (good eaving goUp) eduction (I) FoRm aloxde H OH -O-' akanes 2) eheRs Oxdation of alcohoLs leads to ketones, aLdehydes, and caRboxylic acids These func tional groups, in tuRn, undergo a wide variety oF additionaL reactions oR these rea sons, alcohol oxidations are some of the most common organic reactions. n inorganic chemistry, we think of oxidation as a loss of eLectrons and Reduction as a gain of electrons This pictUre woRKs well For inorganic ions, as when Cr 6 + is redUced to CR 3 + Most organic compounds are unchaRged, However, and gain oR Loss of eLectRons is not obvious Organic chemsts tend to think of oxidation as the ResuLt of adding an oxidizing agent (2, Br2, etc), and reductIon as thE resuLt of adding a reducing agent (2, aB4, etc.). Most organic chemists habituaLLy use the following simpLe rules, based on the change in the formula of the substance: OXDATON: addtion of oR 02; addition oF X2 (Haogens); loss oF 2 REDUCTON: addton of 2 (oR ) Loss of oR 02 Loss oF X2 NETHER: addition oR oss oF + 20, X, etc iS netheR an oxdation nor a Reducton 11-1 OxidatIon StaTes of AlcohoLs and ReLaTed FuncTIonaL Groups 461 H I R- C - H i H alkane no bonds to 0 H I R- C - R' I H alkane no bonds to 0 H I R - C R' i R" alkane No bonds to 0 [0] - 0 H I R C- H I H primary aLcohol oe bond to 0 H R C - R' i H secondary alcohol one boNd to 0 0] H i R C - R i R tertIary acohol oNe bond to 0 0 o II R C H + H20 aldehyde Two bonds to 0 o R -- R + H2 0 ketoNe two bonds o 0 0] - o i R - C H carboxylIc acId tHree bonds to 0 (no ute oxidation) (usually no ute oxidation We can telL that an oxidation or a Reduction of an aLcohoL has taken pLace by counting the numbeR of C - 0 bonds to the caRbon atom. FoR example, in a pRimary alcohol, the carbinol ( C - H ) carbon atom has one bond to oxygen; in an aldehyde, the carbonyL carbon has two (moRe oxidized) and in an acid, it has thRee. Oxidation of an alcohol usu- aLly converts C - H bonds to C - 0 bonds If we conveRt an alcohoL to an aLkane, the...
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