{ diff(x1, t) = ((-1)*k15*x1 + (-1)*k1*k16*x1*(x12 + k17*x7 - k18*x6) + 1*k1*k23*x1*x6 + (-1)*k41*x1*(k42*x2/x3 + k43*x8/(x11 + 100)))/k1,
  diff(x2, t) = (-1)*k1*(k38*x2*x7*x11 - k39*x3)/k1,
  diff(x3, t) = (1*k1*(k38*x2*x7*x11 - k39*x3) + (-1)*k1*k54*x3)/k1,
  diff(x4, t) = (1*k41*x1*(k42*x2/x3 + k43*x8/(x11 + 100)) + (-1)*k1*k44*x4)/k1,
  diff(x5, t) = (1*k1*k44*x4 + (-1)*k1*k45*x5 + (-1)*k50*x5)/k1,
  diff(x6, t) = (-1)*k1*k51*x6*(k58*k52 + x11*k53)/k1,
  diff(x7, t) = ((-1)*k1*k9*x7*x2 + 1*k19*k58*(x1*(k20*x9 + k21*x16) - k22*x18))/k1,
  diff(x8, t) = ((-1)*k2*k10*x8*(k11*x7 + k12*x16 + k13*x12) + (-1)*k2*k29*x8*x1 + 1*k2*k40*x9)/k2,
  diff(x9, t) = (1*k2*k10*x8*(k11*x7 + k12*x16 + k13*x12) + 1*k2*k30*x11*(k31*x7 + k32*x16 + k33*x12) + (-1)*k2*k40*x9 + 1*k2*k55*x11)/k2,
  diff(x10, t) = 0,
  diff(x11, t) = (1*k2*k29*x8*x1 + (-1)*k2*k30*x11*(k31*x7 + k32*x16 + k33*x12) + (-1)*k2*k55*x11)/k2,
  diff(x12, t) = (1*k34*k57*(k35*x16 + x1 - k36*x18) + (-1)*k2*k37*x12)/k2,
  diff(x13, t) = ((-1)*k14*x13 + 1*k15*x1)/k3,
  diff(x14, t) = 0,
  diff(x15, t) = 0,
  diff(x16, t) = ((-1)*k3*k7*x16 + (-1)*k3*(k26*x16 - k27*x1*x18) + 1*k28*x22)/k3,
  diff(x17, t) = ((-1)*k3*k8*x17 + 1*k25*x23)/k3,
  diff(x18, t) = ((-1)*k3*k5*x18 + 1*k24*x20 + 1*k3*(k26*x16 - k27*x1*x18))/k3,
  diff(x19, t) = ((-1)*k4*k6*x19 + 1*k14*x13 + (-1)*k4*k46*x19 + (-1)*k4*k47*x19*x3/(k49*x2 + k48*x8))/k4,
  diff(x20, t) = ((-1)*k24*x20 + 1*k50*x5)/k4,
  diff(x21, t) = 0,
  diff(x22, t) = ((-1)*k28*x22 + 1*k4*k46*x19)/k4,
  diff(x23, t) = ((-1)*k25*x23 + 1*k4*k47*x19*x3/(k49*x2 + k48*x8))/k4 }