By the same token, it can be shown that the
concentrations of hydroxide ions within
the fiber [OH-]f and in the dyebath
[OH-], (where subscript s means in the
solution or dyebath) are also responsible
for the rate at which the reactivity of the
dye for the fiber is lost, due to the nonfiber
reaction of the dye. This undersirable side
reaction is called hydrolysis.
The big surprise to chemists was that it
does not require extreme alkalinity to
generate cellulosate ions, and that these
are many times more reactive than cellulose
itself.
Since both the cellulosate ions and
hydroxide ions are negatively charged, it
makes sense that they would be “on the
look-out’’ for areas within molecules
which are electron deficient-i.e., positively
polarized-with which to react.
These include carbon atoms adjacent to
nitrogen in the aromatic heterocyclic rings
which make up many reactive groups (see
later). Such negataively charged species
are called nucleophiles; hydroxide and
cellulosate ions are nucleophilic reagents.