Am.  Jour.  Pharm. \ 
December,  1895.  / 
Trimethylene  Glycol  in  Glycerin. 
633 
THE  OCCURRENCE   OF  TRIMETHYLENE  GLYCOL 
AS  A  BY-PRODUCT  INT  THE  GLYCERIN 
MANUFACTURE.1 
During  the  past  winter  our  attention  was  called  to  an  unusual 
difficulty  experienced  by  one  of  the  soap-making  firms  in  the  neigh- 
borhood of  Boston,  in  obtaining  their  glycerin  of  the  required  com- 
mercial gravity.  The  information  furnished  in  regard  to  it  indicated 
the  presence  in  the  glycerin  of  some  uncommon  impurity,  and  a 
considerable  quantity  of  the  "  light  stuff"  having  been  generously 
placed  at  our  disposal  by  the  soap  company,  we  were  enabled  to 
investigate  it.  It  was  submitted  to  fractional  distillation,  first  at 
diminished  and  then  at  ordinary  pressure,  and  a  liquid  boiling  be- 
tween 2140  and  2 1 70  at  760  mm.  pressure  was  thus  separated  from 
it.  This  liquid  was  found  to  have  a  specific  gravity  of  1-056  at  j^o> 
and  gave  the  following  results  on  analysis  : 
0-2293  gramme  substance  gave  0-3998  gramme  carbon  dioxide 
and  0-2158  gramme  water. 
The  substance  is,  therefore,  trimethylene  glycol,  which  has  a  boil- 
ing point  of  2140  and  a  specific  gravity,  at  L80°,  of  1-0526.  The 
isomeric  propylene  glycol  boils  at  i88°-i89°,  and  has  a  specific 
gravity  of  1-0403  at  -^S-  The  "  light  stuff"  contained  a  very  con- 
siderable proportion,  about  38  percent.,  of  glycol. 
The  origin  of  the  glycol  is  a  matter  of  considerable  interest. 
There  is  little  doubt  that  it  was  produced  by  fermentation  of  the 
glycerin. 
For  it  has  already  been  shown  by  Freund2  that  trimethylene  gly- 
col is,  in  fact,  one  of  the  principal  fermentation  products  of  that  sub- 
stance. It  is,  moreover,  highly  probable  that  the  glycol  was  present 
in  the  fat  before  saponification  by  the  alkali,  as  the  fermentation  can 
hardly  have  taken  place  in  the  soap  lye,  both  on  account  of  its  saline 
character,  and  on  account  of  the  short  time  intervening  between  the 
1Read  at  the  Springfield  Meeting  of  the  American  Chemical  Society,  1895^ 
and  printed  in  the  Journal  of  that  Society,  17,  890. 
2  Monatsh.  Chem.,  2,  638. 
By  Arthur  A.  Noyes  and  Wii^ard  H.  Watkins. 
Carbon  .  . 
Hydrogen 
Found. 
47*52 
10*46 
Calculated 
for  C3H802. 
47 '37 
io'53 
