Avoid mixture of chloroalkanes

I think it is impossible to make pure 1-chlorocyclohexane as you have said a
mixture of chloroalkanes will be given.

To make 1-chlorocyclohexane as major product, you may mix one mole of cyclohexane and one mole of chlorine, so that the main product would be
1-cholorocyclohexane.

Excess cyclohexane can minimize the chance of 1-chlorocyclohexane
undergoing further reaction. If excess chlorine is used instead, 1,1,1,2,2,2,3,3,3,4,4,4,5,5,5,6,6,6-octadecachlorocyclohexane will be the major
product.

Additional Information:
UV
R-H + X2 -------> R-X + HX
Where R is an alkyl group and X is a halogen

2013-06-13 17:24:56 補充：
The word UV should be on the above of the arrow ----->

alkane只係得substitution reaction,要用UV/Cl2

UV(or sunlight)is to break down the bond betwwn Cl---Cl