PP- Phenol-Water System .pdf

Phenol water system

1. PHENOL-WATER SY

TEM
sme miscibility Pattern of phenol-water system i eur
”abolic curve is obtained. A showa in Haus 6

Upper

CS.T.

66.8 One liquid
phase

Temperature (°C)

o 34 100
Composition (per cent w/w phenol)

Figure 6-2. Phase solubility diagram of phenol-water system.

1. The left-hand side of the parabolic curve represents the gonju-
_ gate solution, which depicts the percentage (w/w) of ph enol in
water at various temperatures.(As the temperature increases, the

solubility of phenol in water increases.)
ae)

2. Eine right-hand side of the parabolic Ste ee eae

on, which depicts the percentage (AV Of way
peratures. (AS the temperature INereay,

con
enol sous te
in phenol at varon
the solubility of water in phenol ido
These two curves meet at a maximum temperature This po
he curve corresponds lo a temperature of 66.8 °C and y
position of 33 A, AC this temperature, the
ly one layer results
solution temperatuire (CST) is de
at which the two conjugate solutions (layers) m
me layer at all proportions.
This temperature is also known as upper consolute temperany
CST of phenol-water system is 66.8 "C. À

ases)

solutions merge and on

ned as maxi

At any temperature above the critical solution temperature, py
hol and water are miscible in all proportions. A single layer
and water is observed.

ju

pheno
5. Outside the curves, phenol and water are miscible, ie. e
ase (or single layer) is formed.

6. Under the curve. normally liquids exist as two layers, Comp
miscibility is possible depending on the composition of À
xture

On the line, the temperature represents miscibility temperatur
that composition. Both liquids give single layer/
The tie line is represented by the line drawn parallel to the bast!

from two points on the curve at any temperature in the phase diagm#
partially miscible liquids

The important feature of tie line is that all systems present on 1%
line, at equilibrium, will separate into phases of constant compos")
Therelore, at a desire temperature, a tie fine can be drawn A
relative amounts of each component in the two layers are calculs?)
‘The other ps

attilly miscible liquid systems of this type are

1. Methanol-cyclohexane (C: PR)

. —49 °C, composition —29%

lexane-aniline (CST—59.6 °C, composition —80% WW} J

3. Carbon disulphide-meihanol (
wiw).

149.5 °C, composilie”

3. TRIETHYLAMINE—WATER SYSTEM

The temperature composition curve (mutual miscibilit

y) of triethyl.
amine and water is given in Figure 6-3 ef ulehyl

2 Two liquid

e phases

4
18.: lower

CST.

One liquid phase

o ai 100
Composition
(per cent w/w triethylamine)

Figure 6-3. Phase solubility diagram of triethylamine-water system.

(2) The left-hand side of the curve indicates the miscibility of
triethylamine in water. The miscibility of triethylamine in water
is decreased with increase in temperature of the system

} ©) The right-hand side of the curve indicates the solubility ol water
in triethyla rhe solubility of water in triethylamine ©

4. p and become a single phase
jon—50% triethylamine in va.
J critical solution temperature or

(6) The two conjugate solutions IM}
at and below 18.5 °C (compos
ter). This temperature is called
lower consolute temperature.

re is defined as the minimum tem.

njugate solutions (layer) are miscible

Lower consolute temperate
perature at which the two co)
in all proportions
Miscibility at lower temperature is implicated as the formation
of a single compound from both components. +

low the lower consolute temperature, tr.

(4) At any temperature bel x a
ethylamine and water are miscible in all proportions. A single
layer is obtained.

(e) Outside the curves, triethylamine and water are miscible, je.

one phase (or single layer) is formed.
(O) Above the curve, normally conjugate solutions exist as two layer |

(g) On the line, the temperature represents miscibility temperature x]
that composition. Both liquids give single layer.

(h) The equi-composition line (50-50) will be completely misc]
at 10°C. But at 50 °C, there will be separation of two layers.
Other systems exhibiting lower consolute temperature are:
1. Dimethylamine-water (CST—43 °C; composition—13.0% wis}
2. 1-Methylpiperidine-water (CST—48 °C; composition—5.0% wit
3. Paraldehyde—normal saline.
4. Water-Tween 80 (CST—60 °C).
“Application
__ This principle is applied in the preparation of de. 1
sists of a solution of paraldehyde lo acosa saline. oa m
yore rapid solution. Therefore, this et

5. NICOTINE-WATER SYSTEM
omposition curve (mutual solubility) of n

Figure 6-4.
to be a combination of earlier two type

erature, nicotine and water are mis

6. 2. At higher temperature, the mutual solubilit =

3, Farther increase in temperature leads to enhanced soy
anced solubi
4, At lower temperatures also, their mutual solubility d bility
lecre
5. As temperature is further lowered, their mutual solubifit =
a ity increase,

Thus nicotine and water exhibit a closed solubility c
sem has lower and upper critical solution temperatures, "is

Y decreases

For nicotine-water system,
Upper consolute temperature — 208 °C; compositi
e ; sition —
nicotine in water. Pa = |

Lower consolute temperature — 61 °C; co; Pr
o ; composition —
nicotine in water. il a2 WW

One liquid phase

Upper
CST.

Two liquid
phases

Temperature (°C)

Lower
CS.

One liquid phase

Composition
(per cent w/w nicotine)

Figure 6-4. Phase solubility diagram of nicotine-water system.

As

Cig the Pressure is increased on this system, lower consolute tempera-
la on and upper consolute temperature is lowered. At and above
cular pressure, the two conjugate solutions are miscible in all pro-

ions an
_ and at all temperatures. )