\frac{dx_{1}}{dt} = \left(-1 \cdot k_{2} \cdot x_{12} \cdot x_{1} \cdot k_{13} + -1 \cdot k_{6} \cdot x_{1} \cdot k_{13} + 1 \cdot k_{7} \cdot x_{2} \cdot k_{13}\right) / k_{13}\\
\frac{dx_{2}}{dt} = \left(1 \cdot k_{6} \cdot x_{1} \cdot k_{13} + -1 \cdot k_{7} \cdot x_{2} \cdot k_{13}\right) / k_{13}\\
\frac{dx_{3}}{dt} = \left(1 \cdot k_{2} \cdot x_{12} \cdot x_{1} \cdot k_{13} + -1 \cdot k_{3} \cdot x_{3} \cdot x_{7} \cdot k_{13}\right) / k_{13}\\
\frac{dx_{4}}{dt} = \left(1 \cdot k_{3} \cdot x_{3} \cdot x_{7} \cdot k_{13} + -1 \cdot k_{4} \cdot x_{4} \cdot k_{13}\right) / k_{13}\\
\frac{dx_{5}}{dt} = \left(1 \cdot k_{4} \cdot x_{4} \cdot k_{13} + -1 \cdot k_{5} \cdot x_{5} \cdot k_{13}\right) / k_{13}\\
\frac{dx_{6}}{dt} = \left(-1 \cdot k_{8} \cdot x_{6} \cdot x_{3} \cdot k_{13} + -1 \cdot k_{8} \cdot x_{6} \cdot x_{4} \cdot k_{13} + 1 \cdot k_{9} \cdot x_{7} \cdot x_{8} \cdot k_{13}\right) / k_{13}\\
\frac{dx_{7}}{dt} = \left(1 \cdot k_{8} \cdot x_{6} \cdot x_{3} \cdot k_{13} + 1 \cdot k_{8} \cdot x_{6} \cdot x_{4} \cdot k_{13} + -1 \cdot k_{9} \cdot x_{7} \cdot x_{8} \cdot k_{13}\right) / k_{13}\\
\frac{dx_{8}}{dt} = 0 / k_{13}\\
\frac{dx_{9}}{dt} = \left(-1 \cdot k_{10} \cdot x_{9} \cdot x_{7} \cdot k_{13} + 1 \cdot k_{11} \cdot x_{10} \cdot x_{8} \cdot k_{13}\right) / k_{13}\\
\frac{dx_{10}}{dt} = \left(1 \cdot k_{10} \cdot x_{9} \cdot x_{7} \cdot k_{13} + -1 \cdot k_{11} \cdot x_{10} \cdot x_{8} \cdot k_{13}\right) / k_{13}\\
\frac{dx_{11}}{dt} = 1 \cdot x_{10} \cdot k_{12} \cdot k_{13} / k_{13}