432 
Manufacture  of  Ceresin. 
Am.  Jour.  Pharm. 
Sept.,  1886. 
layer  of  ceresin  that  forms  at  the  top  is  drawn  off  and  filtered 
through  paper;  the  residue  is  pressed,  whilst  still  in  a  warm  pasty 
condition,  in  hydraulic  presses,  the  runnings  being  also  filtered 
through  paper.  As  a  result  of  these  operations  only  about  two-thirds 
of  the  ceresin  present  in  the  ozokerite  is  obtained,  the  other  third 
being  retained  in  the  press  residue.  This  is  now  generally  recovered 
by  extraction,  petroleum  benzin  being  the  solvent  used  in  most  fac- 
tories, and  only  here  and  there  carbon  bisulphide.  The  ceresin  ex- 
tracted is  freed  from  traces  of  the  solvent  by  passing  superheated 
steam  through  it  and  then  filtered.  The  entire  yield  by  this  method 
of  operating  amounts  to  '70  to  75  parts  of  white,  or  80  to  85  parts 
yellow  ceresin  from  100  parts  of  ozokerite  used. 
According  to  the  second  method  of  working  the  dehydrated  ozo- 
kerite is  introduced  into  the  mixing  vessel  in  the  melted  condition  at 
the  lowest  possible  temperature,  and  then  mixed  by  means  of  a  me- 
chanical stirrer  or  a  current  of  dry  air  with  exactly  the  quantity  of 
sulphuric  acid  required  to  effect  the  reaction.  After  standing  the  top 
layer  of  dark  colored  but  clear  ceresin  is  drawn  off  into  another  ves- 
sel, where  it  is  neutralized  and  decolorized  and  then  filtered.  The 
black  tarry  residue  is  neutralized  and  submitted  to  distillation,  the 
distillate  consisting  of  paraffin  and  mineral  oils.  This  method  has 
many  disadvantages  and  is  not  largely  followed.  Both  methods  are, 
indeed,  defective,  since  it  is  known  that  crude  ozokerite  can  be  made 
to  yield  90  to  92  per  cent,  of  a  white  bleached  product,  instead  of 
the  70  to  75  per  cent,  usually  obtained  in  manufactories. 
The  filtered  ceresin,  if  intended  for  yellow  goods,  is  brought  up  to 
the  right  tint  by  means  of  gamboge,  turmeric,  dragon's  blood,  or  one 
of  the  various  aniline  colors  soluble  in  fats,  and  then  poured  into 
moulds  to  cool.  The  "  half  white  "  and  "  white  "  ceresin  is  stirred 
continually  while  cooling  to  prevent  crystallization,  and  it  is  not  until 
it  has  solidified  to  a  pasty  consistence  that  it  is  poured  into  the 
moulds.  In  this  way  a  whiter  appearance  in  reflected  light  is  pro- 
duced. 
White  ceresin  is  frequently  mixed  by  the  manufacturers  with  the 
lower-priced  paraffin  and  the  yellow  ceresin  with  resin.  The  addi- 
tion of  paraffin  cannot  be  detected  either  by  chemical  tests  or  deter- 
mination of  the  specific  gravity.  It  is,  however,  hardly  to  be  deemed 
an  adulteration  since  in  some  cases,  as  for  illuminating  purposes,  its 
presence  is  advantageous.     The  addition  of  resin  ought,  however,  to 
