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Problem 6 Atomic and molecular orbitals - PianetaChimica.it

Problem 6 Atomic and molecular orbitals - PianetaChimica.it

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<strong>Problem</strong> 18 Polymer synthesis33 rd International Chemistry Olympiad ∗ Preparatory <strong>Problem</strong>sEthylene finds extensive application in the manufacture of polymers <strong>and</strong> bulkchemicals. It is produced on a large scale by thermal <strong>and</strong> catalytic cracking ofalkanes obtained from natural gas <strong>and</strong> petroleum.In the presence of silver catalyst, ethylene reacts w<strong>it</strong>h oxygen to give P. CompoundP on heating w<strong>it</strong>h acidified water forms Q. 1 H-NMR spectrum of P has only onesignal while that of Q contains two signals.a. Identify <strong>and</strong> draw the structures for compounds P <strong>and</strong> Q.Compound R is obtained when P <strong>and</strong> Q react w<strong>it</strong>h each other. R reacts w<strong>it</strong>h SOCl 2to give S. On heating w<strong>it</strong>h alcoholic KOH, S gives T, an anaesthetic under the name"vinethene".PSOCl 2alc.KOH+ QR S Tb. Identify compounds R, S <strong>and</strong> T.Another compound dimethyl benzene-1,4-bis(acetate) can be synthesised fromp-xylene. Such a synthesis requires use of proper reagents so that desiredintermediate compounds <strong>and</strong> the final product are obtained. Various intermediatecompounds obtained in the synthesis of dimethyl benzene-1,4-bis(acetate) alongw<strong>it</strong>h their structures are shown below.COOHCOOCH 3CH 3CH 2BrCH 2CNCH 2CH 2??? ?????CH 3CH 2BrCH 2CNCH 2CH 2p-xyleneCOOHCOOCH 3Dimethyl benzene -1,4 -bisacetatec. Identify the reagents used in this synthesis of dimethyl benzene –1,4-bis(acetate).Mumbai, India, July25 25

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