quaternize
/ˈkwɒtənʌɪz/(also quaternise) Chemistry
verb
1 [with object] To convert (an atom or compound, especially a tertiary amine) into a quaternary form.
2 [no object] Of an atom or compound: to be converted into a quaternary form.
Origin
1930s; earliest use found in Journal of the American Chemical Society. From quatern- + -ize.