A quantitative property-property relationship for the internal diffusion coefficients of organic compounds in solid...

Area of Science:

• Environmental Chemistry
• Occupational Health
• Materials Science

Background:

• Indoor organic chemical releases from solids significantly contribute to human exposure.
• Current methods for estimating diffusion coefficients are limited in scope and applicability.
• Accurate diffusion coefficient prediction is crucial for assessing chemical migration and human exposure.

Purpose of the Study:

• To develop and validate a quantitative property-property relationship (QPPR) for predicting diffusion coefficients.
• To establish a model applicable to a wide array of organic chemicals and solid materials.
• To facilitate high-throughput estimation of human exposures to encapsulated chemicals.

Main Methods:

• Compiled a comprehensive dataset of 1103 diffusion coefficients for 158 chemicals across 32 material types.
• Developed a multiple linear regression model incorporating chemical molecular weight, temperature, and material type.
• Conducted internal and external validations to assess model robustness and predictive accuracy.

Main Results:

• The developed QPPR model achieved an adjusted R² of .93.
• Internal validations confirmed the model's robustness, stability, and statistical significance.
• External validation demonstrated good predictive ability (Rext² > .8) within the defined applicability domain (MW: 30–1178 g/mol, Temp: 4–180°C).

Conclusions:

• The QPPR model provides a reliable method for predicting diffusion coefficients across a broad range of chemical-material systems.
• This approach significantly enhances the ability to estimate human exposure to chemicals encapsulated in solid materials.
• The model supports improved risk assessment and management strategies for indoor environments.