Standard Operating Procedure
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Read the EH&S Standard Operating Procedures Fact Sheet before filling out this form.
Print out the completed form and keep a readily accessible hard copy in the lab (also
keeping an electronic copy is highly recommended).
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Date:
May 22, 2012
SOP Title:
Potassium Hydride
Principal Investigator:
Richmond Sarpong
Room and Building:
841A Latimer Hall
Lab Phone Number:
(510) 643-2485
Section 1 – Process
Section 2 – Hazardous Chemicals
Potassium hydride is a highly moisture sensitive reagent that reacts violently with air and/or water.
Upon reaction with water, it can ignite.
Section 3 – Potential Hazards
Potassium hydride is extremely flammable upon exposure to water, and as such is generally sold as a
dispersion in mineral oil. It must be handled under an inert atmosphere to minimize exposure to both
air and moisture. It can cause severe burns and is highly corrosive. In addition to the high
flammability, potassium hydride is extremely destructive to the tissue of mucous membranes.
Section 4 – Approvals Required
Use of potassium hydride requires training and the approval of the appropriate lab member.
Section 5 – Designated Area
Potassium hydride should only be used in the fume hood.
Section 6 – Special Handling Procedures and Storage Requirements
Clear all areas where the reagent will be opened prior to use. Do not use any potassium hydride while
working alone.
Weigh the desired amount of the potassium hydride/mineral oil suspension in a beaker. Wash the
potassium hydride three times with dry hexanes (20 mL/g KH) and suspend the washed potassium
hydride in the dry, ethereal solvent (THF, Et2O) of choice. Transfer the suspension to a flame-dried
flask equipped with a stir bar. Next, fit the flask with a septum, pierce the septum with a clean, dry
needle attached to a Schlenk line, and purge the flask with nitrogen. A typical purge procedure is as
follows. First, evacuate the reaction vessel using a vacuum pump attached to the Schlenk line until the
solvent begins to boil (indicated by bubbling). Then, replace the atmosphere above the solvent with
nitrogen gas delivered via the Schlenk line. Finally, repeat this procedure twice more to ensure that all
of the air has been removed from the flask.
After successfully weighing out the potassium hydride, the substrate and any addition reagents can be
added to the flask. After the reaction vessel has been cooled to the desired temperature, slowly add a
solution of the substrate, prepared with the same dry, ethereal solvent as above, through the septum
using a cannula (volumes > 15 mL) or syringe (preferred for smaller volumes) while continuing to
supply an inert atmosphere via the Schlenk line.
Upon completion of the desired reaction, excess potassium hydride can be quenched by adding excess
butanol dropwise to a reaction vessel cooled to 0 ° C followed by the dropwise addition of excess
cold water.
Section 7 – Personal Protective Equipment
Wear a laboratory coat made of flame-retardant material or cotton. Wear flame-resistant gloves over
the top of chemically resistant gloves, and safety glasses.
Section 8 – Engineering/Ventilation Controls
Work inside the hood. Keep the hood sash as low as possible to prevent spills/splashes outside the
hood.
Section 9 – Spill and Accident Procedures
In case of a fire, use Metal-X, soda ash, or sand for small fires. For large fires, use an ABC fire
extinguisher. Do not use water on the fire. In case of contact with your person, get to the nearest
safety shower immediately. Remove all contaminated clothing and get underneath the running water
quickly. The large amount of water should put out the fire.
Section 10 – Waste Disposal
Fully quench the reagent before disposal. To quench potassium hydride, dilute the concentration of
potassium hydride below 5 % w/v with dry hexane. Cool the resulting solution to 0 ° C and add excess
t-butyl alcohol dropwise under nitrogen with stirring. Then, add excess cold water dropwise. Separate
the resulting aqueous and organic layers. The aqueous layer can be neutralized and disposed in the
sink. The organic layer can be disposed as normal solvent waste.
Section 11 - Decontamination
Remove all contaminated clothing, wash all contaminated skin with copious amounts of water.
Section 12 – Process Steps
Process Steps
Safety Measures
Training Documentation
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