1) CH4 --(1500oC, LLN)--> HC≡CH+ H2
2HC≡CH --(150oC, CuCl2)--> HC≡C-C(-H, =CH2)
HC≡C-C(-H, =CH2) + HCl --> H2C=C(-Cl, -CH=CH2)
2) CH4 --> CH3Cl --> CH3OH --> CH3COOH --> (CH3)2-CO --> CH3-C(-CH3, -OH)-CN --> CH3-C(CH3, OH)-COOH --> CH2=C(-CH3)-COOH --> CH2=C(-CH3)-COO-CH3