TMAOH has been used as a base in organic chemistry in general and in PTC in particular for many years.
Dr. Neal Anderson of Anderson’s Process Solutions, brought to our attention an important reference that is important for the safety of PTC process chemists who use tetramethylammonium hydroxide (TMAOH) as a base.
It is strongly recommended that before using TMAOH, or even considering using TMAOH, please read the information sheet shown here: https://ehs.stanford.edu/wp-content/uploads/21-012-TMAH-Fact-Sheet.pdf.
When you read the Stanford fact sheet, pay close attention to the following excerpts: “The key factor that makes TMAH particularly hazardous is how quickly it acts. Life-threatening symptoms can develop within 20 minutes, unconsciousness within 30, and, in the worst cases, death can occur within an hour.” Other important information is cited here: “It is important to remember, however, that life-threatening symptoms may occur with concentrations as low as 2%.”
We can speculate the the hydrophilic-lipophilic properties that make TMAOH useful as a base in organic reactions in polar solvents may be the same properties that make it toxic to biological systems with affinity to similar hydrophilic-lipophilic properties.
TMAOH has been used as a base in organic chemistry in general and in PTC in particular for many years. Of great commercial importance was the replacement of KOH by TMAOH in chip manufacture several decades ago to increase yield. KOH was used in the early days of chip manufacture but tiny amount of residual ions on the chip rendered them unusable. TMAOH was then used to replace KOH since upon heating, the TMAOH undergoes decomposition by nucleophilic attack to form methanol and trimethylamine, both of which are volatile and evaporate from the surface of the chip, leaving no ionic residue.
The PTC community thanks Dr. Anderson for bringing this important information to our attention. Please visit Dr. Anderson’s website for useful process development tips, consulting and training services.
