Preparation of Bromodeoxycellulose and Derivatives from Shambat Cotton Lint Using Dimethyl Acetamide / Lithium Bromide Solvent System

Abstract

This study was designed to prepare cellulose derivatives  with different   functional  groups  from  Sudanese  Shambat  cotton lint using   a homogenous   solubilisation  medium. The raw cotton lint was   mercerized    in   (15%)   NaOH     solution   to   weaken   the aggregation   of    the   bundles   of   cellulose    fibers;    and    was subsequently      dissolved      in     N,N-dimethylacetamide/lithium bromide    (DMA/LiBr)    as    a homogenous      solvent     system. Bromodeoxycellulose   was    synthesized   by   treatment,   of   the     solubilised   cotton  cellulose with N-bromosuccinimide (NBS)  in the    presence   of   triphenylphosphine   (Ph3P)   to   convert   the hydroxyl  groups  into  the  bromodeoxy  derivative  of   cellulose. The  chemical   structure  this  derivative  was  investigated  using infrared  spectroscopy,  elemental  analysis  which  confirmed  the presence  of  C-Br   bonds.  Thermal   analysis   (TGA,  DSC)  has shown     that    unlike   chlorordeoxycellulose    and    unmodified mercerized  cotton, bromodeoxycellulose was relatively thermally stable.  Azido  and  amino  deoxycellulose  were   easily  prepared from   bromodeoxycellulose   since   bromide   is  a good  leaving. Solubility in some organic solvents was tested to explore possible new uses and applications