\frac{dx_{1}}{dt} = \operatorname{piecewise}(1 / 2190, k_{22} = 0, 1 / 2190) \cdot \operatorname{piecewise}(1000, k_{22} = 0, 1000) - \operatorname{piecewise}(\frac{33}{100}, k_{22} = 0, \frac{1}{4}) \cdot \left(x_{5} + x_{6} + x_{7}\right) \cdot \operatorname{piecewise}(19, k_{22} = 0, 19) / \left(\operatorname{piecewise}(\frac{33}{100}, k_{22} = 0, \frac{1}{4}) \cdot \left(x_{5} + x_{6} + x_{7}\right) + \operatorname{piecewise}(19, k_{22} = 0, 19) \cdot \left(x_{1} + x_{3} + x_{2} + x_{4}\right)\right) \cdot \operatorname{piecewise}(\frac{21}{100}, k_{22} = 0, \frac{21}{100}) \cdot x_{7} / \left(x_{5} + x_{6} + x_{7}\right) \cdot x_{1} - \operatorname{piecewise}(1 / 2190, k_{22} = 0, 1 / 2190) \cdot x_{1}\\
\frac{dx_{2}}{dt} = \operatorname{piecewise}(\frac{2}{5}, k_{22} = 0, \frac{2}{5}) \cdot \operatorname{piecewise}(\frac{33}{100}, k_{22} = 0, \frac{1}{4}) \cdot \left(x_{5} + x_{6} + x_{7}\right) \cdot \operatorname{piecewise}(19, k_{22} = 0, 19) / \left(\operatorname{piecewise}(\frac{33}{100}, k_{22} = 0, \frac{1}{4}) \cdot \left(x_{5} + x_{6} + x_{7}\right) + \operatorname{piecewise}(19, k_{22} = 0, 19) \cdot \left(x_{1} + x_{3} + x_{2} + x_{4}\right)\right) \cdot \operatorname{piecewise}(\frac{21}{100}, k_{22} = 0, \frac{21}{100}) \cdot x_{7} / \left(x_{5} + x_{6} + x_{7}\right) \cdot x_{1} - \left(\operatorname{piecewise}(1 / 2190, k_{22} = 0, 1 / 2190) + \operatorname{piecewise}(1 / 4, k_{22} = 0, 1 / 4)\right) \cdot x_{2}\\
\frac{dx_{3}}{dt} = \left(1 - \operatorname{piecewise}(\frac{2}{5}, k_{22} = 0, \frac{2}{5})\right) \cdot \operatorname{piecewise}(\frac{33}{100}, k_{22} = 0, \frac{1}{4}) \cdot \left(x_{5} + x_{6} + x_{7}\right) \cdot \operatorname{piecewise}(19, k_{22} = 0, 19) / \left(\operatorname{piecewise}(\frac{33}{100}, k_{22} = 0, \frac{1}{4}) \cdot \left(x_{5} + x_{6} + x_{7}\right) + \operatorname{piecewise}(19, k_{22} = 0, 19) \cdot \left(x_{1} + x_{3} + x_{2} + x_{4}\right)\right) \cdot \operatorname{piecewise}(\frac{21}{100}, k_{22} = 0, \frac{21}{100}) \cdot x_{7} / \left(x_{5} + x_{6} + x_{7}\right) \cdot x_{1} - \left(\operatorname{piecewise}(1 / 2190, k_{22} = 0, 1 / 2190) + \operatorname{piecewise}(1 / 4, k_{22} = 0, 1 / 4) + \operatorname{piecewise}(\frac{1}{10}, k_{22} = 0, \frac{1}{10})\right) \cdot x_{3}\\
\frac{dx_{4}}{dt} = \operatorname{piecewise}(1 / 4, k_{22} = 0, 1 / 4) \cdot x_{3} + \operatorname{piecewise}(1 / 4, k_{22} = 0, 1 / 4) \cdot x_{2} - \operatorname{piecewise}(1 / 2190, k_{22} = 0, 1 / 2190) \cdot x_{4}\\
\frac{dx_{5}}{dt} = \left(x_{5} + x_{6} + x_{7} - \operatorname{piecewise}(\frac{1}{10}, k_{22} = 0, \frac{1}{10}) \cdot x_{7}\right) / \left(x_{5} + x_{6} + x_{7}\right) \cdot \operatorname{piecewise}(1 / 20, k_{22} = 0, 1 / 14) \cdot \operatorname{piecewise}(20000, k_{22} = 0, 4000) - \operatorname{piecewise}(\frac{33}{100}, k_{22} = 0, \frac{1}{4}) \cdot \operatorname{piecewise}(19, k_{22} = 0, 19) \cdot \left(x_{1} + x_{3} + x_{2} + x_{4}\right) / \left(\operatorname{piecewise}(\frac{33}{100}, k_{22} = 0, \frac{1}{4}) \cdot \left(x_{5} + x_{6} + x_{7}\right) + \operatorname{piecewise}(19, k_{22} = 0, 19) \cdot \left(x_{1} + x_{3} + x_{2} + x_{4}\right)\right) \cdot \left(\operatorname{piecewise}(\frac{7}{10}, k_{22} = 0, \frac{7}{10}) \cdot x_{3} / \left(x_{1} + x_{3} + x_{2} + x_{4}\right) + \operatorname{piecewise}(\frac{3}{10}, k_{22} = 0, \frac{3}{10}) \cdot x_{2} / \left(x_{1} + x_{3} + x_{2} + x_{4}\right)\right) \cdot x_{5} - \operatorname{piecewise}(1 / 20, k_{22} = 0, 1 / 14) \cdot x_{5}\\
\frac{dx_{6}}{dt} = \operatorname{piecewise}(\frac{33}{100}, k_{22} = 0, \frac{1}{4}) \cdot \operatorname{piecewise}(19, k_{22} = 0, 19) \cdot \left(x_{1} + x_{3} + x_{2} + x_{4}\right) / \left(\operatorname{piecewise}(\frac{33}{100}, k_{22} = 0, \frac{1}{4}) \cdot \left(x_{5} + x_{6} + x_{7}\right) + \operatorname{piecewise}(19, k_{22} = 0, 19) \cdot \left(x_{1} + x_{3} + x_{2} + x_{4}\right)\right) \cdot \left(\operatorname{piecewise}(\frac{7}{10}, k_{22} = 0, \frac{7}{10}) \cdot x_{3} / \left(x_{1} + x_{3} + x_{2} + x_{4}\right) + \operatorname{piecewise}(\frac{3}{10}, k_{22} = 0, \frac{3}{10}) \cdot x_{2} / \left(x_{1} + x_{3} + x_{2} + x_{4}\right)\right) \cdot x_{5} - \left(\operatorname{piecewise}(1 / 20, k_{22} = 0, 1 / 14) + \operatorname{piecewise}(1 / 14, k_{22} = 0, 1 / 14)\right) \cdot x_{6}\\
\frac{dx_{7}}{dt} = \operatorname{piecewise}(\frac{1}{10}, k_{22} = 0, \frac{1}{10}) \cdot x_{7} / \left(x_{5} + x_{6} + x_{7}\right) \cdot \operatorname{piecewise}(1 / 20, k_{22} = 0, 1 / 14) \cdot \operatorname{piecewise}(20000, k_{22} = 0, 4000) + \operatorname{piecewise}(1 / 14, k_{22} = 0, 1 / 14) \cdot x_{6} - \operatorname{piecewise}(1 / 20, k_{22} = 0, 1 / 14) \cdot x_{7}