1. What is Octanol-Water Partition Coefficient?

Definition: The Octanol-Water Partition Coefficient (K_ow) is defined as the ratio of the concentration of a solute in a water-saturated octanolic phase to its concentration in an octanol-saturated aqueous phase.

Purpose: It's a key parameter in environmental chemistry and pharmacology that measures how a substance partitions between a lipid (octanol) and water phase.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( K_{ow} \) — Octanol-Water Partition Coefficient (dimensionless)
• \( C_{octanol} \) — Concentration of solute in octanol phase (mol/m³)
• \( C_{water} \) — Concentration of solute in water phase (mol/m³)

Explanation: The ratio indicates the compound's hydrophobicity - higher values mean more lipophilic (fat-soluble) compounds.

3. Importance of K_ow Calculation

Details: K_ow is crucial for predicting environmental fate of chemicals, drug absorption, and toxicity assessment.

4. Using the Calculator

Tips: Enter the concentrations in octanol and water phases in mol/m³. Both values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What does a high K_ow value indicate?
A: High K_ow (>10,000) indicates a lipophilic compound that tends to accumulate in fatty tissues.

Q2: What's the typical range for K_ow?
A: It can range from 10^-3 (hydrophilic) to 10⁷ (extremely hydrophobic).

Q3: How is K_ow related to bioaccumulation?
A: Compounds with log K_ow > 5 are more likely to bioaccumulate in organisms.

Q4: Why use octanol specifically?
A: Octanol mimics biological membranes better than pure hydrocarbons, making it a standard reference.

Q5: How is K_ow measured experimentally?
A: Typically by shaking the compound with octanol-water mixture and measuring concentrations in each phase.