  We investigate the chemical segregation of complex O-bearing species
(including the largest and most complex ones detected to date in space) towards
Orion KL, the closest high-mass star-forming region. The molecular line images
obtained using the ALMA science verification data reveal a clear segregation of
chemically related species depending on their different functional groups. We
map the emission of 13CH3OH, HCOOCH3, CH3OCH3, CH2OCH2, CH3COOCH3, HCOOCH2CH3,
CH3CH2OCH3, HCOOH, OHCH2CH2OH, CH3COOH, CH3CH2OH, CH3OCH2OH, OHCH2CHO, and
CH3COCH3 with 1.5" angular resolution and provide molecular abundances of these
species toward different gas components of this region. We disentangle the
emission of these species in the different Orion components by carefully
selecting lines free of blending and opacity effects. Possible effects in the
molecular spatial distribution due to residual blendings and different
excitation conditions are also addressed. We find that while species containing
the C-O-C group, i.e. an ether group, exhibit their peak emission and higher
abundance towards the compact ridge, the hot core south is the component where
species containing a hydroxyl group (-OH) bound to a carbon atom (C-O-H)
present their emission peak and higher abundance. This finding allows us to
propose methoxy (CH3O-) and hydroxymethyl (-CH2OH) radicals as the major
drivers of the chemistry in the compact ridge and the hot core south,
respectively, as well as different evolutionary stages and prevailing physical
processes in the different Orion components.
