Recycling of acid-superbase conjugate ionic liquids by water removal in the lyocell spinning process

According to the present invention, there is provided a process for the production of a cellulose filaments or films, comprising the steps of dissolving a cellulose substrate in an ionic liquid consisting of the superbase cation 7-methyl-l,5,7-triazabicyclo[4.4.0]dec-5-enium [mTBDH]+ and an anion to produce a solution forming a spinning dope, said anion being derived from an acid which is present at a stoichiometric excess to the superbase, extruding the spinning dope through a spinneret in a coagulation bath containing water to form filaments or films from the solution, withdrawing ionic liquid in an aqueous mixture with water from the coagulation bath, recovering the ionic liquid [mTBDH][OAc] from the aqueous mixture by removing water and optionally recycling the recovered ionic liquid to the dissolution step.