C2H5OH -> C2H4 -> CH2 (-OH) - CH2 (-OH)
C2H4 + H2 = C2H6 C2H6 + Cl2 = C2H5Cl + HCl C2H5Cl + NaOH = NaCl + C2H5OH C2H5OH = C2H4 + H2O nC2H4 = -(CH2-CH2)-n