1,4-Phenylene Diisocyanate (PPDI) is a chemical compound characterized by its specific physical and chemical properties, which dictate its handling, storage, and application. Understanding these attributes is crucial for safe and effective utilization in industrial and research settings. As a white to light yellow crystalline solid, PPDI possesses a distinct appearance that is easily identifiable.

Chemically, PPDI is known for its reactivity, particularly its sensitivity to moisture. It reacts slowly with water, which can lead to the formation of carbon dioxide. This moisture sensitivity necessitates careful storage and handling to maintain product integrity and prevent degradation. It is typically stored in a cool, dry, and well-ventilated place, in tightly sealed containers to protect it from atmospheric moisture. Incompatibility with strong oxidizing agents, strong acids, strong alkalis, alcohols, and amines also requires careful consideration during storage and use.

From a safety perspective, PPDI is classified as combustible. While its flash point is relatively high, appropriate precautions against ignition sources are always necessary. Inhalation, skin contact, and ingestion can be harmful, and it may cause sensitization by inhalation. Therefore, wearing suitable protective clothing, gloves, and eye protection is paramount when working with this compound. Ensuring adequate ventilation in work areas is also essential to minimize exposure risks. Following safety data sheets (SDS) and adhering to recommended handling procedures is critical for any personnel working with 1,4-Phenylene Diisocyanate.

The melting point of PPDI typically falls between 96-99 °C, indicating its solid state at room temperature. Its boiling point is around 236.2 °C at standard atmospheric pressure. These physical constants, along with its chemical reactivity profile, underscore the importance of specialized knowledge when incorporating PPDI into synthesis or manufacturing processes. Proper management of its properties ensures both safety and the successful application of this valuable chemical intermediate.