Product
Chemistry
Science
Chapter
on
PHMB
(
20%
Formulations
of
Vantocil
P
and
Vantocil
IB)

August
4,
2004
Case
3122
PC
Code
111801
A.
Najm
Shamim,
Ph.
D.
Office
of
Pesticide
Programs
Antimicrobials
Division
U.
S.
Environmental
Protection
Agency
1200
Pennsylvania
Avenue,
NW
Washington,
DC
20460
Page
2
of
3
A.
Chemical
Overview
Vantocil
IB
and
Vantocil
P
are
both
microbiocides
containing
20%
w/
w
poly(
hexamethylenebiguanide)
hydrochloride.
They
are
registered
with
the
Agency
for
use
as
disinfectants.

B.
Chemical
Identification
°
Name:
Poly(
hexamethylenebiguanide)
hydrochloride
°
Formulations:
Vantocil
P/
Vantocil
IB
°
IUPAC
Name:
Poly(
iminoimidocarbonyliminoimidocarbonyliminohexamethylene
hydrochloride
°
Other
Names:
Aqueous
solution
of
poly(
hexamethylenebiguanide)
hydrochloride;
polyhexanide
°
CAS
Numbers:
27083­
27­
8
32289­
58­
0
°
Empirical
Formula:
(
C
8
H
17
N
5
.
HCl)
n+
1
where
n=
1
to
about
40,
average
n
value
is
between
10­
13
°
Structure:
X
­
((
CH
2
)
3
­
NH
­
C
­
NH
­
C
­
NH
­
(
CH
2
)
3
)
n
­
X
  
  
NH
NH
.
HCl
Where
X
=
HCl.
NH
2
­
(
CH
2
)
3
Or
X
=
­
(
CH
2
)
3
­
NH
­
C
­
NH
­
CN
  
NH
Or
X
=
­
(
CH
2
)
3
­
NH
­
C
­
NH
2
.
HCl
  
NH
C.
Physical/
Chemical
Properties
The
following
characteristics
have
been
reported
for
Vantocil
P:

°
Color:
Very
faint
yellow
°
Physical
State:
Mobile
liquid
°
Boiling
Point:
100.2oC
°
Specific
Gravity:
1.04
at
20oC
°
Dissociation
Constant:
1.2
±
0.5
x
10­
1
at
25oC
Page
3
of
3
°
pH
of
5%
solution:
5.7
°
Stability:
14
days
at
54
±
2oC
°
Melting
point:
Does
not
melt;
decomposition
onset
205oC
­
210oC
°
Water
Solubility:
40
g/
100
g
solution
°
Solubility
in
organic
solvents:
methanol
>
26g/
100g
solvent
acetone
2.7
ppm
dichloromethane
0.2
ppm
toluene
0.2
ppm
ethyl
acetate
0.1
ppm
n­
hexane
0.1
ppm
acetonitrile
0.8
ppm
K
OW
*
2.3
x
10­
3
(
reported
only
for
Vantocil
IB)

*
It
can
be
assumed
that
the
general
physical/
chemical
characteristics
of
Vantocil
IB
are
similar
to,
if
not
the
same
as
Vantocil
P.
