Environmental Health and Safety

Pyrophorics Guidelines

Purpose

Pyrophoric materials are those that are capable of spontaneous combustion in the presence of air. Spontaneous ignition or combustion takes place when these substances reach ignition temperature without application of external heat. Ignition may be delayed or only occur if the material is finely divided or spread as a diffuse layer (titanium powder is an example in the first case, and mixed tributyl phosphine isomers is an example in the second). Ignition can be instantaneous, such as with trimethylaluminum. The following classes of compounds are prone to pyrophoricity. These materials burn at high temperatures and will react violently with water, air, and/or other chemicals. Handle with care!

Classes of Pyrophoric Compounds

Pyrophoric materials should be stored in tightly closed containers under an inert atmosphere or liquid. All transfers and manipulations of them must also be carried out under an inert atmosphere or liquid.

Personal Protective Equipment (PPE)

Required Work Practices

The following general guidelines must be followed while working with pyrophoric materials.

Know the properties and hazards of all chemicals you are using.

Select and obtain all necessary materials to dispense and use the reagent(s) safely.

Transferring Liquid Pyrophorics

Flex syringes (double-tipped needles) can be used for transferring materials. Flex syringes are constructed of tubing with needles attached to both ends for materials transfer through septa. A supply of low-pressure inert gas can be used to introduce the material to a reaction vessel, graduated addition funnel or graduated syringe. Tubing with a single needle may be needed to introduce the inert gas.

Appropriate glassware and reaction equipment

Inert gas for purging air and material transfer

Syringes may also be used to withdraw small quantities of liquid reagent (<50 mL) from containers when a supply of inert gas is provided to displace the quantity withdrawn.

Never work alone with pyrophorics. Ensure someone can see or hear you.

Purchase quantities that will ensure use of the entire product within one year.

Use containers with transfer septa (i.e. Aldrich Sure/Seal) for liquid reagents.

Visually check the container and reaction vessel septa for degradation before use.

Emergency Procedures

A Class D fire extinguisher or powdered lime should be available in the lab.

Do not clean up spills. Contain the spill and/or extinguish the fire only if you can do so safely. Evacuate the lab and contact EHS (512-471-3511) immediately.