Shunyaya Symbolic Mathematical Chemistry — Catalytic hydrogenation (C2H4 + H2 -> C2H6) (6.9)

Why this page. A plain ASCII bond-basis worked example showing sign and boundedness of RSI, plus a transparent catalyst prior and condition gate g_t. Numbers are illustrative; sign is the invariant. Use clamps and guards throughout.


Reaction

C2H4 + H2 -> C2H6

Bond basis (kJ/mol, illustrative)

B_C=C = 614, B_C-C = 348, B_H-H = 436, B_C-H = 413

Inputs (study constants for this example)

E_unit = 100, c = 0.5, gamma = 1

Tally (contrast)

E_broken = 1 * B_C=C + 1 * B_H-H
         = 614 + 436
         = 1050

E_formed = 1 * B_C-C + 2 * B_C-H
         = 348 + 2 * 413
         = 1174

e = (E_formed - E_broken) / E_unit
  = (1174 - 1050) / 100
  = +1.24

Alignment assignment (symmetric, bounded)

a_r = tanh(-c * e) = tanh(-0.5 * 1.24) = tanh(-0.62) ~ -0.55112803
a_p = tanh(+c * e) = tanh(+0.62)                     ~ +0.55112803

# clamp before any atanh (guard):
a_r = clamp_a(a_r, eps_a)
a_p = clamp_a(a_p, eps_a)

RSI computation (stoichiometric weights)

W_r = |1| + |1| = 2

U_r = sum_r( |m_r|^gamma * atanh_safe(a_r, eps_a) ) = 2 * (-0.62000000) = -1.24000000
V_p = sum_p( |m_p|^gamma * atanh_safe(a_p, eps_a) ) = 1 * (+0.62000000) = +0.62000000

RSI = tanh( (V_p - U_r) / W_r_safe )
    = tanh( (0.62 - (-1.24)) / 2 )
    = tanh( 0.93 )
    ~ +0.73059390

Optional catalyst prior (CPI on product path, transparent, small)

delta_u = alpha * Index = 0.20 * 0.80 = +0.16  # apply to product term only

V_p' = 0.62 + 0.16 = 0.78
s'   = (0.78 - (-1.24)) / 2 = 1.01
RSI' = tanh(1.01) ~ +0.76576202

Verdict. Favored (moderate); sign(e) > 0 aligns with sign(RSI) > 0. A small, declared prior increases magnitude but preserves boundedness and transparency.

Gate note (illustrative)

If g_t = 0.80 -> RSI_env ~ 0.80 * 0.73059390 = 0.58447512
If g_t = 0.30 -> RSI_env ~ 0.30 * 0.73059390 = 0.21917817

Data posture. Illustrative bond basis for sign and magnitude sketch; publish actual lens/tables and any priors if used.


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Disclaimer (observation-only). All formulas and results are observation-only—not predictive or operational—and require peer validation and governance before any deployment.