🧪 PyThermoEst

PyThermoEst is a Python toolkit for estimating thermodynamic properties from group-contribution methods. It currently supports the Joback method for estimating a wide range of properties and the Zabransky–Ruzicka method for predicting the liquid-phase heat capacity.

Calculations can also be done on your mobile with the MoziThermoCalc iOS app: Download on the App Store.

📦 Installation

pip install pyThermoEst

🚀 Usage

The package exposes convenience helpers in pyThermoEst.app for both calculation workflows. See the examples/ directory for runnable scripts.

🧬 Joback property estimation

Provide Joback group contributions along with the total number of atoms, then call joback_calc. You can mix field names or their documented aliases when building JobackGroupContributions.

from pyThermoEst import joback_calc
from pyThermoEst.models import JobackGroupContributions, GroupUnit

payload = {
    "-CH3": GroupUnit(value=2),
    "=CH- @ring": GroupUnit(value=3),
    "=C< @ring": GroupUnit(value=3),
    "-OH @phenol": GroupUnit(value=1),
}

joback_groups = JobackGroupContributions(**payload)

# or dict with aliases:
# joback_groups = {
#     "-CH3": 2,
#     "=CH- @ring": 3,
#     "=C< @ring": 3,
#     "-OH @phenol": 1,
# }

result = joback_calc(groups=joback_groups, total_atoms_number=18)

# Evaluate a temperature-dependent property, e.g., heat capacity at 273 K
cp_273 = result["heat_capacity"]["value"](273)
print(cp_273)

💧 Zabransky–Ruzicka liquid heat capacity

To compute liquid heat capacity, provide required group contributions and optional correction terms, then call zabransky_ruzicka_calc.

from pyThermoEst import zabransky_ruzicka_calc
from pyThermoEst.models import (
    ZabranskyRuzickaGroupContributions,
    ZabranskyRuzickaGroupContributionsCorrections,
    GroupUnit,
)

payload = {
    "C-(H)3(O)": GroupUnit(value=2),
    "CO-(O)2": GroupUnit(value=1),
    "O-(C)(CO)": GroupUnit(value=2),
}

contributions = ZabranskyRuzickaGroupContributions(**payload)
corrections = ZabranskyRuzickaGroupContributionsCorrections()

# or dicts with aliases:
# contributions = {
#     "C-(H)3(O)": 2,
#     "CO-(O)2": 1,
#     "O-(C)(CO)": 2,
# }

result = zabransky_ruzicka_calc(
    group_contributions=contributions,
    group_corrections=corrections
)
cp_liq_at_300k = result["value"](298.15)
print(cp_liq_at_300k, result["unit"], result["symbol"])

📚 Getting group contribution IDs and names

You can inspect available group contribution identifiers and names for each method:

🧬 Joback group contributions

from pyThermoEst.docs.joback import (
    joback_group_contribution_info,
    joback_group_contribution_names,
    joback_group_contribution_ids
)

# Get all group contribution IDs (aliases)
group_ids = joback_group_contribution_ids()

# Get all group contribution names (field names)
group_names = joback_group_contribution_names()

# Get both names and IDs as tuples
names, ids = joback_group_contribution_info()

💧 Zabransky–Ruzicka group contributions

from pyThermoEst.docs.zabransky_ruzicka import (
    zabransky_ruzicka_group_contribution_info,
    zabransky_ruzicka_group_contribution_names,
    zabransky_ruzicka_group_contribution_ids,
    zabransky_ruzicka_group_correction_info,
    zabransky_ruzicka_group_correction_ids,
    zabransky_ruzicka_group_correction_names
)

# Get group contribution IDs (aliases)
group_ids = zabransky_ruzicka_group_contribution_ids()

# Get group contribution names (field names)
group_names = zabransky_ruzicka_group_contribution_names()

# Get both names and IDs as tuples
names, ids = zabransky_ruzicka_group_contribution_info()

# Get correction term IDs
correction_ids = zabransky_ruzicka_group_correction_ids()

# Get correction term names
correction_names = zabransky_ruzicka_group_correction_names()

# Get both correction names and IDs as tuples
corr_names, corr_ids = zabransky_ruzicka_group_correction_info()

📖 Further examples

• examples/joback-exp-0.py: Inspect available Joback group IDs and names.
• examples/joback-exp-1.py: Build Joback group payloads with field names or aliases.
• examples/joback-exp-2.py: Full Joback calculation including temperature evaluation.
• examples/zabransky-ruzicka-exp-0.py: Inspect available Zabransky–Ruzicka group IDs, names, and corrections.
• examples/zabransky-ruzicka-exp-1.py: Zabransky–Ruzicka calculation with optional corrections.

🔧 API reference

• pyThermoEst.app.joback_calc(groups, total_atoms_number): Runs Joback method and returns calculated properties.
• pyThermoEst.app.zabransky_ruzicka_calc(group_contributions, group_corrections=None): Returns an equation for liquid heat capacity plus units and symbol metadata.

Each function accepts either the pydantic models or plain dictionaries keyed by group identifiers; aliases are supported for convenience.

📝 License

This project is licensed under the MIT License. You are free to use, modify, and distribute this software in your own applications or projects. However, if you choose to use this app in another app or software, please ensure that my name, Sina Gilassi, remains credited as the original author. This includes retaining any references to the original repository or documentation where applicable. By doing so, you help acknowledge the effort and time invested in creating this project.

❓ FAQ

For any question, contact me on LinkedIn