CHAPTER FIVE Structure and Preparation of Alkenes: Elimination Reactions CH=CH— as in CH,=CHCl ion of poly(vinyl CH,=CHCH,- as in CH,-CHCH,OH hloride). Poly(vinyl chlo- Allyl Allyl alcohol de), often called simpl CH,=C—asin CH=CCI including siding for house all coverings, and PvC pip Isopropenyl chloride When a CH2 group is doubly bonded to a ring, the prefix methylene is added to the name of the ring. Cycloalkenes and their derivatives are named by adapting cycloalkane terminal gy to the principles of alkene nomenclature CH 1-Methvleyclohexene 3-chlorocvclohe (not l-chloro-2-cycloheptene No locants are needed in the absence of substituents: it is understood that the double bond connects C-I and C-2 Substituted cycloalkenes are numbered beginning with the double bond, proceeding through it, and continuing in sequence around the ring. The direction of numbering is chosen so as to give the lower of two possible locants to the substituent PROBLEM 5.2 Write structural formulas or build molecular models and give the UPAC names of all the monochloro-substituted derivatives of cyclopentene 5.2 STRUCTURE AND BONDING IN ALKENES The structure of ethylene and the orbital hybridization model for the double bond were presented in Section 1. 17. To review, Figure 5. 1 depicts the planar structure of ethylene, its bond distances, and its bond angles. Each of the carbon atoms is sp-hybridized, and the double bond possesses a o component and a T component. The o component results when an sp- orbital of one carbon, oriented so that its axis lies along the internuclear axis, overlaps with a similarly disposed sp- orbital of the other carbon. Each sp- orbital contains one electron, and the resulting g bond contains two of the four electrons of the double bond. The T bond contributes the other two electrons and is formed by a"side- y-side"overlap of singly occupied p orbitals of the two carbons Back Forward Main MenuToc Study Guide ToC Student o MHHE WebsiteWhen a CH2 group is doubly bonded to a ring, the prefix methylene is added to the name of the ring. Cycloalkenes and their derivatives are named by adapting cycloalkane terminol￾ogy to the principles of alkene nomenclature. No locants are needed in the absence of substituents; it is understood that the double bond connects C-1 and C-2. Substituted cycloalkenes are numbered beginning with the double bond, proceeding through it, and continuing in sequence around the ring. The direction of numbering is chosen so as to give the lower of two possible locants to the substituent. PROBLEM 5.2 Write structural formulas or build molecular models and give the IUPAC names of all the monochloro-substituted derivatives of cyclopentene. 5.2 STRUCTURE AND BONDING IN ALKENES The structure of ethylene and the orbital hybridization model for the double bond were presented in Section 1.17. To review, Figure 5.1 depicts the planar structure of ethylene, its bond distances, and its bond angles. Each of the carbon atoms is sp2 -hybridized, and the double bond possesses a component and a  component. The component results when an sp2 orbital of one carbon, oriented so that its axis lies along the internuclear axis, overlaps with a similarly disposed sp2 orbital of the other carbon. Each sp2 orbital contains one electron, and the resulting bond contains two of the four electrons of the double bond. The  bond contributes the other two electrons and is formed by a “side￾by-side” overlap of singly occupied p orbitals of the two carbons. Cyclopentene Cl 1 2 3 4 6 5 7 3-Chlorocycloheptene (not 1-chloro-2-cycloheptene) 1 CH3 2 3 4 5 6 1-Methylcyclohexene Methylenecyclohexane CH2 CH2œCH± Vinyl as in CH2œCHCl Vinyl chloride CH2œCHCH2± Allyl as in CH2œCHCH2OH Allyl alcohol CH2œC± as in W CH3 Isopropenyl W CH3 CH2œCCl Isopropenyl chloride 170 CHAPTER FIVE Structure and Preparation of Alkenes: Elimination Reactions Vinyl chloride is an industrial chemical produced in large amounts (1010 lb/year in the United States) and is used in the preparation of poly(vinyl chloride). Poly(vinyl chlo￾ride), often called simply vinyl, has many applications, including siding for houses, wall coverings, and PVC pip￾ing. Back Forward Main Menu TOC Study Guide TOC Student OLC MHHE Website