\ceCH4+\ceCH4+\ceCl2\ceCl2\ce−>[光]\ce−>[光]\ceCH3Cl+\ceCH3Cl+\ceHCl\ceHCl
\ceCH3Cl+\ceCH3Cl+\ceCl2\ceCl2\ce−>[光]\ce−>[光]\ceCH2Cl2+\ceCH2Cl2+\ceHCl\ceHCl
\ceCH2Cl2+\ceCH2Cl2+\ceCl2\ceCl2\ce−>[光]\ce−>[光]\ceCHCl3+\ceCHCl3+\ceHCl\ceHCl
\ceCHCl3+\ceCHCl3+\ceCl2\ceCl2\ce−>[光]\ce−>[光]\ceCCl4+\ceCCl4+\ceHCl\ceHCl