Alkyl Halides Based on McMurry's Organic Chemistry,6th edition,Chapter 10
Alkyl Halides Based on McMurry’s Organic Chemistry, 6th edition, Chapter 10
What Is an Alkyl Halide ■ An organic compound containing at least one carbon- halogen bond(C-X) X(F,CI,Br,I)replaces H Properties and some uses CI F Br F C-H Fire-resistant solvents CI CI ■Refrigerants Trichloroethylene Halothane ■Pharmaceuticals and (a solvent) (an inhaled anesthetic) precursors F H Cl-C-F H-C-Br C H Dichlorodifluoromethane Bromomethane a refrigerant) (a fumigant)
What Is an Alkyl Halide An organic compound containing at least one carbonhalogen bond (C-X) X (F, Cl, Br, I) replaces H Properties and some uses Fire-resistant solvents Refrigerants Pharmaceuticals and precursors
Naming Alkyl Halides Step 1:Find the longest chain and name it as the parent If a multiple bond is present,the parent must contain it. Step 2:Number the carbons of the parent chain beginning at the end nearer the first substituent,regardless of whether it is alkyl or halo. CH2 Br Br CH3 CH,CHCH2CHCHCH2CH3 CH CHCH2CHCHCH2CH3 23 4.56 123 4562 CHg CH3 5-Bromo-2.4-dimethvlheptane 2-Bromo-4.5-dimethvlheptane
Naming Alkyl Halides Step 1: Find the longest chain and name it as the parent. If a multiple bond is present, the parent must contain it. Step 2: Number the carbons of the parent chain beginning at the end nearer the first substituent, regardless of whether it is alkyl or halo
Naming with Multiple Halides ■If more than one of the CI CI same kind of halogen is present,use prefix CH CHCHCHCH2CH3 1 2345 6 di,tri,tetra CH3 ■If there are several different halogens, 2.3-Dichloro-4-methvlhexane number them and list them in alphabetical CH3 Br order H:CHCH2CH2CHCH3 543 2-Bromo-5-methylhexane (NOT 5-bromo-2-methylhexane)
Naming with Multiple Halides If more than one of the same kind of halogen is present, use prefix di, tri, tetra If there are several different halogens, number them and list them in alphabetical order
Structure of Alkyl Halides Halogens increase in size going down the periodic table, so the C-X bond is longer as you go down periodic table C-X bond is weaker as you go down periodic table C-X bond is polarized with slight positive on carbon and slight negative on halogen TABLE 10.1 A Comparison of the Halomethanes Bond length Bond strength Dipole moment Halomethane (pm) (k]/mol) (kcal/mol) (0) CHaF 139 452 108 1.85 CHCI 178 351 84 1.87 CHgBr 193 293 70 1.81 CHI 214 234 56 1.62
Structure of Alkyl Halides Halogens increase in size going down the periodic table, so the C-X bond is longer as you go down periodic table C-X bond is weaker as you go down periodic table C-X bond is polarized with slight positive on carbon and slight negative on halogen