[ Eq(Derivative(x1, t), ((-1)*k23*k12*x1 + 1*k22*k13*x2 + (-1)*k23*k16*x1*x3*x13)/k23),
  Eq(Derivative(x2, t), (1*k23*k12*x1 + (-1)*k22*k13*x2 + 1*k22*k18*x15)/k22),
  Eq(Derivative(x3, t), ((-1)*k23*k14*x3 + 1*k22*k15*x4 + (-1)*k23*k16*x1*x3*x13)/k23),
  Eq(Derivative(x4, t), (1*k23*k14*x3 + (-1)*k22*k15*x4 + 1*k22*k18*x15)/k22),
  Eq(Derivative(x5, t), (1*k23*k1 + (-1)*k23*k5*x5 + 1*k23*k6*x6 + (-1)*k23*k3*x5 + 1*k23*k4*x7 + (-1)*k23*k8*x16*x8*x5 + 1*k23*k6*x12 + 1*k23*k4*x13)/k23),
  Eq(Derivative(x6, t), (1*k23*k5*x5 + (-1)*k23*k6*x6)/k23),
  Eq(Derivative(x7, t), (1*k23*k3*x5 + (-1)*k23*k4*x7 + (-1)*k23*k10*x7)/k23),
  Eq(Derivative(x8, t), (1*k23*k2 + (-1)*k23*k5*x8 + 1*k23*k6*x9 + (-1)*k23*k3*x8 + 1*k23*k4*x10 + (-1)*k23*k8*x16*x8*x5 + 1*k23*k6*x12 + 1*k23*k4*x13)/k23),
  Eq(Derivative(x9, t), (1*k23*k5*x8 + (-1)*k23*k6*x9)/k23),
  Eq(Derivative(x10, t), (1*k23*k3*x8 + (-1)*k23*k4*x10 + (-1)*k23*k11*x10)/k23),
  Eq(Derivative(x11, t), (1*k23*k8*x16*x8*x5 + (-1)*k23*k5*x11 + (-1)*k23*k3*x11)/k23),
  Eq(Derivative(x12, t), (1*k23*k5*x11 + (-1)*k23*k6*x12 + (-1)*k23*k9*x12*x15)/k23),
  Eq(Derivative(x13, t), (1*k23*k3*x11 + (-1)*k23*k4*x13 + (-1)*k23*k7*x13)/k23),
  Eq(Derivative(x14, t), (1*k23*k16*x1*x3*x13 + (-1)*k23*k17*x14)/k23),
  Eq(Derivative(x15, t), (1*k23*k17*x14 + (-1)*k22*k18*x15)/k22),
  Eq(Derivative(x16, t), (1*k23*k4*x10 + (-1)*k23*k8*x16*x8*x5 + 1*k23*k6*x12 + 1*k23*k4*x13)/k21) ]