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Notes  on  Essential  Oils. 
( Am.  Jour.  Pliarru 
\       June,  1891. 
NOTES  ON  ESSENTIAL  OILS. 
By  Geo.  M.  Beringer,  Ph.G. 
Abstracted  from  tlie  Semi-annual  Report  of  Schimmel  &  Co. 
Bitter  Almond  Oil. — In  the  preceding  semi-annual  report,  Messrs.  Schimmel 
&  Co.  called  attention  to  the  fact  that  the  artificial  benzaldehyde  of  commerce 
prepared  from  benzyl  chloride  is  always  more  or  less  contaminated  with 
chlorine  compounds,  and  proposed  tests  for  this  element  as  a  means  of  detect- 
ing adulteration.  (See  Amer.  Journ.  Pharmacy,  1891,  p.  43).  E.  Merck 
has  recently  stated  that  genuine  bitter  almond  oil  is  not  always  free  from 
chlorine  compounds,  and  has  recently  placed  on  his  list  an  ol.  amygdal. 
amarum  verurn  containing  chlorine.  The  same  manufacturer  also  claims  to 
make  and  quotes  on  his  price-list  a  purified  benzaldehyde  free  from  chlorine. 
As  a  result  of  their  examination  of  this  latter  product,  Messrs.  Schimmel  & 
Co.  state  that  it  is  not  chlorine  free,  its  chlorine  being  readily  detected  by  the 
combustion  method.1 
The  assertion  that  pure  bitter  almond  oil  may  contain  chlorine  is  less  easily 
refuted,  as  nothing  is  vouchsafed  as  to  the  preparation  of  such  an  oil  or  as  to 
the  nature  of  the  chlorine  compounds  contained  therein.  Messrs.  Schimmel 
state  that  in  the  course  of  the  last  15  years  they  have  worked  many  thousand 
hundredweight  of  almonds,  of  peach  and  apricot  kernels  of  the  most  varied 
kinds,  but  never  have  been  able  to  detect  in  it  any  chlorine,  although  for  more 
than  8  years  they  have  carried  out  the  relative  investigations  with  great  regu- 
larity (as  control  estimations  in  the  testing  of  doubtful  oils  of  commerce). 
The  chlorine  compounds  in  bitter  almond  oil  could  be  of  various  nature  ;  either 
organic  compounds,  benzyl  chloride,  mono-  and  dichlorine  substitution 
products  of  benzaldehyde  and  of  benzyl  alcohol,  etc.,  or  minute  traces  of 
inorganic  chlorides  (chloride  of  sodium  and  of  calcium)  which  would  originate 
from  the  process  of  rendering  the  oil  anhydrous.  Chlorine  compounds  of  the 
latter  kind  are  not  detected  by  the  combustion  method,  but  would  be  shown 
by  the  process  of  testing  recommended  by  Heppe. 
Chlorination  substitution  products  may  be  detected  the  following  method. 
A  small  quantity  of  the  oil  is  oxidized  with  a  warm  alkaline  solution  of  potas- 
sium permanganate,  excess  of  the  latter  decomposed  by  the  addition  of  a  few 
drops  of  alcohol,  the  whole  filtered  and  the  filtrate  acidified  with  diluted  pure 
H2S04.  After  complete  cooling  has  taken  place,  the  separated  benzoic  acid — 
wmich  contains  the  organic  chlorine  compounds  (with  the  exception  of  any 
benzylchloride),  in  the  form  of  chlorinated  benzoic  acid — is  thrown  on  a  filter 
and  carefully  washed.  Large  quantities  of  chlorine  in  the  filtrate  indicate  the 
presence  of  organic  chlorides  in  the  oil.  The  benzoic  acid  is  dissolved  in  pure 
potash  solution,  a  little  nitre  added,  the  solution  evaporated  to  dryness  and 
finally  heated  in  a  platinum  dish.  The  residue  of  incineration  is  taken  up  by 
water,  acidified  with  nitric  acid,  filtered  and  tested  for  chlorine. 
Organic  Chlorides  (benzylchloride)  can  be  detected  as  follows, — 5  to  10  grms. 
1  Since  the  publication  of  this  method  (see  Amer.  Journ.  Pharmacy,  1891,  p.  43),  I  have 
had  occasion  to  examine  a  number  of  samples  of  commercial  oil  of  bitter  almonds  and  made 
careful  tests  with  this  method  with  entire  satisfaction.  Certain  samples  of  undoubted  purity 
as,  for  instance,  "  Allen's,"  gave  no  reaction  for  chlorine,  while  a  known  sample  of  synthetic 
gave  a  copious  reaction,  and  mixtures  of  the  two  could  be  easily  detected. — G.  M.  B. 
