Correspondence - "Effect of Temperature on Density and Refractice

Mar 3, 2005 - John Griswold. Ind. Eng. Chem. , 1950, 42 (5), ... J. K. Stanley , Joan von Hoene , and George Wiener. Analytical Chemistry 1951 23 (2),...
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INDUSTRIAL AND ENGINEERING CHEMISTRY

936

+

e

Trial 11. (k,u,b,c)’ =

Vol. 42, No. 5

; C ’ (k,a,b,c)

-

aed

e 0.8531 (k,a,b,c)

Trial 111. Let (k,a,b,c)’ = (0.85368) (k,a,b,c).

For dew point feed the relationship becomes: c = cf

+

1

;

e [acd(a,, - l)(c’

ij d‘)] - 1

+

k’ a’

- 1)

ace(01cd

Le

b’

Olcd ((Yo/

ef

( acol

-

-

C’ _.

f

d

l)(C’ f d ’ ) e’ 1)

F’

a

0.02220 0.01110 0.03756 0,04951 0.58900

11.01 4.20 1.80 P .34 1.0

F’

D’ W’

= 0.67937 = 0.12037 = 0.55900

d’ = 0.50591 (determined as in Trial I).

EXAIIPLE VIII. (kabclde) Mixture. Feed such that B = T. Compute ( L / D ) mfor the complete separation of the following

mixture:

0.058 k

11.01 4.20 1.80 1.34 1.00 0.67

a b

-a C

0.569 0.300

e

=!

0.04951

+

[(E) 0.34

(O-)

0.300 (0.04951 0.04951 0.50591)1] -

+

= 0.05800

+ d‘) -1 - 1) - (0.559) [(1.34)(0.04951) + 0.505911 -

Resolve mixture into (k,a,b,c)‘/d and (k,n,b,c)”/e. Trial I. Let (k,a,b,c)’ = (0.8) (k,a,b,c).

k’ a‘

b’

C‘

d

d=d’+

cd (YW [;bi{aed

F‘

U

0.0208 0.0104 0.0352 0.0464 0.5590

11.01 4.20

( L / D ) m = (L’/D’)m

a

-

1 ) (C’

d(%d

d’ ( k

C‘

+u +b +

c)’(acd

].

(0.50591) (0.12037) (0.34)

1.so

= 14.450

1.34 1.00

J. A. MAY

THEDow CHEMICAL COMPANY FREEPORT, TEX.

+ ]-kid')] -- +

b - 1) (c’ f d’) - 1 ) d‘

(Ycd Gad

=

Effect of Temperature on Density and Refractive Index SIR: In the article, “Effect of Temperature on Density and Refractive Index” by Kurts, Amon, and Sankin [IND. Em. CHENI.,42, 174-6 (1950)], the authors use their simple relation,

Try d’ = 0.50866. ?

0‘559

o’50866

+

0.0352 (1.34) (0.80) (0.0464 0.50866) (1.8) (0.34) (0.50866)

+

[

0.0104 . _ . ~ (1.34) (3.2) (0.55506) (4.20) (0.34) (0.50866)

I-1

+

0.0464 f

(2

0.300

- I ) (0.0464 + 0.50866) (1.34 - 1) (0.0464) 1-11 # 0.0464

as originally proposed by Ward, Kurtz, and Fulweiler (“Science of Petroleum,” Vol. 11, p. 1146, London, Oxford University Press, 1938). By differentiating the Eykman equation, =

dn/dd =

+ 0.00799 = 0.05439

+

C(n 0.4)* (n f 0.4)z 0.84

-

+ 0.03862 + 0.00457 + 0.00715 = 0.55900

(s) 1

An = 0.6 Ad

An/Ad

0.0208 (1.34) (10.01) (0.55506) 0.50866

I-1

+

+

where C is the Eykman constant and n and d are refractive index and density, respectively, taken a t the same temperature [see Dreisbach and Martin, IND.ENG. CHERI.,41, 2875 (1949)]. This gives an accurate coefficient for the first relation. Using the sodium D line and hydrocarbons (as recommended in earlier articles), values of C are frequently between 0.75 and 0.78. The range of An/Ad is rather narrow, usually 0.58 to 0.64, so the constant 0.6 is a good average. But for organic compounds in general, C is almost always below the hydrocarbon range and as low as 0.32 in some instances. An/Ad is below 0.3 for some compounds. This explains the positive and large deviations resulting from the use of the constant 0.6 in Table 111. JOHN GRISWOLD ILLIKOIS INSTITUTE O F TECHNOLOGY CHICAGO, ILL