34 
Preparation  of  Amyl  Nitrite. 
<  Ajxl.  Jour.  Pharm. 
(        Jan.,  1886. 
NOTE  OX  THE  PREPARATION  OF  AMYL  NITRITE. 
By  John  Williams,  F.I.C.,  F.C.S.,  and  Miles  H.  Smith.  F.C.S. 
(Read  before  the  British  Pharmaceutical  Conference.) 
Understanding  that  Mr.  A.  H.  Allen  was  preparing  a  paper  for  this 
meeting  of  the  Conference  upon  the  result  of  testing  the  strength  of 
amyl  nitrite  by  the  very  ingenious  and  useful  instrument,  the  "nitro- 
meter/' which  he  has  lately  improved  and  brought  under  the  notice  of 
pharmacists,  it  appeared  to  us  that  it  would  be  of  interest  to  the  meet- 
ing if  we  gave  an  account  of  a  few  experiments  we  have  lately  under- 
taken to,  if  possible,  settle  certain  points  in  the  manufacture  of  this 
article.  We  were  induced  to  undertake  these  experiments  in  conse- 
quence of  the  discussion  which  has  lately  taken  place  before  the  Chem- 
ical Society  and  elsewhere,  in  which  Professor  Armstrong,  Messrs. 
Ramsey  and  Cundall,  and  Mr.  Lunge  have  taken  part,  the  main  ques- 
tion being  if  nitrous  acid  (N203)  could  exist  in  the  state  of  gas  or  not, 
but  the  experiments  also  showing  that  very  various  results,  as  far  as 
regards  the  nature  of  gas  given  off  by  the  action  of  nitric  acid  upon 
arsenious  acid  or  starch,  could  be  obtained  by  slight  variations  in  the 
conditions  under  which  the  experiment  was  conducted.  It  is  not  our 
wish  or  intention  to  offer  any  opinion  upon  the  main  question  in  dis- 
pute, but  we  think  some  of  our  experiments,  although  rather  rough, 
may  perhaps  throw  some  light  upon  the  question ;  at  any  rate  we  hope 
they  will  prove  of  sufficient  interest  to  Avarrant  their  being  recorded. 
The  process  we  adopt  for  preparing  nitrite  of  amyl  is  at  first  sight 
a  very  simple  one.  A  gas  which  we  have  hitherto  assumed  to  be 
nitrous  acid  (X2Os)  prepared  by  acting  upon  arsenious  acid  by  nitric 
acid  is  passed  into  amyl  alcohol,  previously  purified  and  kept  carefully 
cooled.  A  considerable  quantity  Ox'  the  gas  is  absorbed  and  the  pass- 
age of  the  gas  is  continued  until  the  alcohol  is  saturated,  this  being 
shown  by  a  change  of  color  from  bright  yellow  to  brownish  green; 
beyond  this  point  it  is  not  advisable  to  carry  the  operation.  The  pro- 
duct is  then  well  washed  and  afterwards  subjected  to  distillation,  a 
thermometer  being  inserted  in  the  retort  (but  not  toucliing  the  liquid) 
so  that  the  boiling  point  may  be  observed  and  the  liquid  fractioned  if 
necessary.  The  liquid  generally  begins  to  distil  at  from  80°  to  85° 
C,  and  the  boiling  point  may  rise  very  considerably  if  the  sample  is 
not  pretty  pure.  The  boiling  point  of  pure  nitrite  of  amyl  is  variously 
stated  by  good  authorities,  some  putting  it  as  low  as  90°  to  92°  C, 
