RICHARD J. SlERASKl and GEORGE M. MACHWART Michigan College of ,Mining and Technology, Houghton, Mich.
A, Nomograph f o r .
..
..
Boiling Temperature
by the Meissner Method
This nomograph can be used to determine surface tension, molar refraction, or density at different temperatures a s well as determining boiling points
WHEN
experimentally determined boiling temperatures are not available, they can be predicted with a fair degree of accuracy by the method developed by Meissner ( 3 ) . Atmospheric boiling temperatures may be calculated as follows:
where T B = atmospheric boiling temperature O K. l i ~ = molar refraction based on the sodium D line R = a constant which changes with the class of compound P = parachor
The molar refraction may be determined by the use of atomic and structural refractions or the relationship ( 7 , 2) :
where R D = molar refraction, sodium D line M = molecular weight D = liquid density, grams per cc. AT, = refractive index based on ihe sodium D line
The parachor can also be determined from atomic and structural values, in addition to the use of the following equation : (3) where P = parachor M = molecular weight y = surface tension, dynes per cm.
D = liquid density, grams per cc. d = vapor density, grams per cc. I n the use of the foregoing equations, the liquid and vapor densities, refractive index, and surface tension are all evaluated at the same temperature. For most compounds, the data are reported in the standard literature references, and if they are obtained for a relatively low temperature, the vapor density term may be neglected. A nomograph has been constructed to allow the determination of RD, P, and T B from the basic equation :
D--d where all values are as defined in the previous equations. If the value of either RD or P is known, it can be used directly, without the use of the basic determination.
Table 1. These Physical Characteristics of Phenol Are Used to Determine the Boiling Point Characteristics Molecular weight Liquid density Refractive index, sodium D line Surface tension
Value at Symbol 45O C. X 94.11 D 1.07 grams/cc. ND y
1.54 39.4 dynes/cm.
T h e use of the nomograph is illustrated using phenol (Table I ) as the material for which the boiling point is to be determined. Using a straightedge, mark the intersection on reference line X of the line connecting the molecular weight value M (94.11) and the liquid density value D (1.0745'). Retain the point on X as it will be used again. Pivot the straightedge about the point on X,until it intersects with the desired value on the refractive index line ATn ( 1 . 5 4 4 5 O ) . The intersection of the straightedge with the molar refraction line yields a partial solution which is the molar refraction R D (27.9). Mark and retain this point on R n for later use. Continue to pivot the straightedge about the point on X until it intersects with the value of the surface tension y (39.445'). T h e intersection of the straightedge with the parachor line yields the second partial solution, the parachor (220). This point on P is also retained for later use. Table I1 ( 3 ) lists the values for the compound class constant B , and associates with each constant a value represented by a letter on the reference line B . The value of the compound class constant is added to R D as follows. Place the straightedge between the molar refraction R D (27.9) and E on the B reference line. Mark the intersection on Y, and pivot about it until the proper class constant value is reached on the B reference line (J). T h e new value for the molar refraction Rh (30.9) is read on the RD line. Pivot the straightedge about Rh until the value of the parachor VOL. 52, NO. 10
OCTOBER 1960
869
P
X
RD
600
D
100
0.31
500
'5
ND
400 300
40
4
~~
0.6 L
i3
200
0.8 8 A -
B -
L Q n
10 .
G D - L E-
100
80
F -
3
G
n
-
H -
1
n
4>
2.0
A I 3
60
K
-
L
-
M -
KEY
MOLAR
2 3
2
f3
REFRACTION
PARACHOR
M - X - D No-
-
X
100
M
RD
5
-
BOILING
X - D
X
-
P
TEMPERATURE
RD- Y (CLASSCONSTANT)
P
-
Y
-
E Rb
Rb- TB
This nomograph is used to determine physical constants such as parachor, atmospheric boiling point, a n d molar refraction
P (220) is intersected on the P line. Table
II.
Compound Class Constant B (3)Values Are Given with Their References on Line B
Compound Class Olefin hydrocarbons Tertiary amines Paraffin hydrocarbons Aromatic hydrocarbons Naphthalenic hydrocarbons Acetylenic hydrocarbons Reference point Secondary amines Ethers Mercaptans Monochloro n-paraffins
870
B Value - 4,500
Reference Letter A
- 3,000
B
-2,500
C
- 2,500
C
- 2,500 -
500
Compound Class Primary amines Ketones Esters of monocarboxylic acids and monohydroxy alcohols
B Valuc 6,500
Reference
l i = ~ 27.6
Letter H
which are in close agreement.
15,000
I
15,000
. I
16,500
16,500 16,500
J J J
D
Alcohols, monohydroxy Phenol Cresol
20,000
IC
C
0
E
Nitriles
+ 2 , 000
F
4,000
Monocarboxylic acids
28,000
L
4,000
G G
4,000
G
Esters of dicarboxylic acids and monohydroxy alcohols
30,000
.TI
INDUSTRIAL AND ENGINEERING CHEMISTRY
Read the boiling temperature on the T B line (456' K . ) . Calculated values using Formulas 1, 2, and 3 give:
P
220.4
T,
=
454'K.
Using the same relationships, the nomograph can be used in reverse to determine surface tension, molar refraction, or density a t different Temperatures. if all the factors except one are known.
literature Cited (1) Davis, D. S., Chemical Engineering Nomographr. p . 168 McGraw-Hill. New York, 1944. ( 2 ) Kharbanda, 0. P., Nomograms for Chemical Engineers, pp. 48-51, Academic Press, New York, 1958. ( 3 ) Meissner, H. P., Chem. Eng. Progr. 45, p. 149 (1949). R E C E I V Efor D review March 21, 1960 ACCEPTED June 20, 1960
