2-bromo-3-methylbutane , 2-chlorobutane , 1-chloro-2,2-dimethylpropane. Name the haloalkanes which can be prepared in high yield by monohalogenation of an alkane?

Question

Ava Andrews · Accepted Answer

We should get good yields of 2-chlorobutane and 1-chloro-2,2-dimethylpropane.

We have to look at the relative reactivity of each type of #"H"# atom to radical halogenation and calculate the expected yield. For radical chlorination, the relative reactivities are 1°:2°:3° = 1:3.9:5.2 (the numbers may have been slightly off). For radical bromination, the relative reactivities are 1°:2°:3° = 1:82:1640 (the numbers may have been slightly off). 3-methyl-2-bromo butane #("CH"_3)_2"CHCH"_2"CH"_3 → ("CH"_3)_2"CHCHBrCH"_3 # # 6 × 1° = 6 ×1 =" "" "color(white)(1)6# #1×3° = 1 ×1640 = 1640# #2× 2° = 2× 82 = " "color(white)(1)164# #3× 1° = 3× 1=" "" "color(white)(1)color(white)(1)3# #"Total" =" "" "" "" "" "stackrel color (blue)("———")(1813)# #% 2° = 164/1813 × 100 = 9 %# A 9 percent yield of 2-bromo-3-methylbutane is what we should anticipate. 2. Butane #"CH"_3"CH"_2"CH"_2"CH"_3 → "CH"_3"CH"_2"CHClCH"_3# #6× 1° = 6 × 1 =" "" "6# #4 × 2° = 4 × 3.9 = color(white)(1)15.6# #"Total" =" "" "" "" "color(white)(1)stackrelcolor (blue)(———)21.6# #% 2° = 15.6/21.6 × 100 = 72 % 2°# It is reasonable to anticipate a 72% yield of 2-chlorobutane. 2,2-dimethylpropane-1-chloro #("CH"_3)_2"CHCH"_3 → ("CH"_3)_2"CHCH"_2"Cl"# #9 ×1° = 9× 1 =color(white)(1)color(white)(1)9# #1 × 3° = 1 × 5.2 = 5.2# #"Total" =" "" "" "color(white)(1)color(white)(1)stackrel(———)14.2# #% 1° = 9/14.2 × 100 = 63 % 3°# A yield of 63% for 1-chloro-2,2-dimethylpropane is what we should anticipate. In conclusion, good yields of 1-chloro-2,2-dimethylpropane and 2-chlorobutane should be obtained.

Christian Anderson · Answer

undefined 2-bromo-3-methylbutane and 2-chlorobutane can be prepared in high yield by monohalogenation of an alkane.