3c
(7) Natta, G., Pino, P., Mazzanti, G., Longi, P., GQZZ.chim. ital. 87, 570-85 (1957). (8) Stille, J. K., Chem. Reus. 58, 541-80 (1958).
0
RECEIVED for review April 22, 1959 ACCEPTED July 10, 1959
20
Division of Polymer Chemistry, 134th Meeting, ACS, Chicago, Ill., September 1958.
ae > z
Figure 4. sion-time linear
0
Converis plot
IO
J
7
HEPTANE 25 mi. A I E t S 0.0125 mole C r C I 3 0.0125 mole TEMP. 3 O o C . I
Corrections Slide Rules to Ease Your Chores
i
I
T I M E , hr.
Effect of Polymerization Conditions
Polymerization temperature exerts an influence on the polymerization of propylene monomer. As shown in Figure 3, conversion increases with increasing temperature to a maximum value at about 50’ C. In the analogous titanium system the rate does not show a maximum with increasing temperature in this range but continues to increase ( 5 ) . Temperature also affected the molecular weight of the polymer. The intrinsic viscosity decreased from 1.76 dl. per gram at 30’ C. to only 0.44 at 70” C. The regularity of the polymer also decreased slightly at the elevated polymerization temperature. The specific gravity of the 70’ c. polypropylene was 0.891 compared to 0.900 for the 30’ C. polymer. Conversion varies linearly with time during at least the early portion of the reaction (Figure 4). Extrapolation of the conversion-time line indicates either an induction period or an increasing rate initially. A slow initial rate increasing to a steady value is characteristic of the titanium trichloride-triethylaluminum catalyst system ( 5 ) .
titanium trichloride. In Table IV it is to be noted that the titanium catalyst resulted in 3.4 times the amount of polymer obtained from the chromium catalyst at one fifth the trichloride content. The titanium catalyst had sui%cient activity so that at the highest catalyst concentration, temperature control was lost during the later stages of the polymerization.
The authors acknowledge the contributions of W. E. Marshall in the polymerization experiments and of H. N. Benedict, under whose supervision specific gravity was measured. literature Cited (1) Annis, R. L., Banner, R. G., Kourilo, J., Mahne, F. S., Perrin, T. S., Extrac-
The chromium trichloride is a less active catalyst component than the
Table 111. Chromium Dichloride Is Not a Catalyst Component
Table IV. Chromium Trichloride Is Less Active than Titanium Trichloride
Heptane AIEt, CrC13
25 ml. 0.0125 mole 0.01 25 mole
Temp. Time
3OoC. 1 8 hr.
CrCln/CrCla
Conv., 70
0.00
16 9 0
1.00 m
1368
Heptane 125 mi. AIEtSIMC13 1 .OO
INDUSTRIAL AND ENGINEERING CHEMISTRY
M Cr
Ti
Temp. Time
MCL, Mole X IO2 1.25 2.50 0.25 0.50 0.75
Figure 1. This kind of slide rule solves le, the general equation I C = LA where I is a length proportional to the value of the function. If, for example, the functions are plotted on arithmetic scales, then the slide rule simply adds or subtracts the value of the functions. But if the scales are logarithmic, the slide rule solves the general equation log B,or C = A.B. log C = log A The specific equation solved here i s At - K6m, where At i s the boiling point rise of a solvent caused b y adding a soluble of m molality. Ka i s the solvent’s boiling point constant. Figure 2. This one solves an equation with four variables using logarithmic scales. The equation:
+
+
Acknowledgment
tive Metallurgy Division, Meeting AIME, San Francisco, Calif., February 1959. (2) Danusso, F., Moraglio, G., Makromol. Chem. 28,250-2 (1958). ( 3 ) Danusso, F., Moraglio, G., Natta, G., Znd. plastiques mod. (Paris) 10, No. 1, 40,43-5, 55 (1958). (4) Montecatini Societl, Ziegler, K., Australian Patent App. 14,116/55 (Nov. 30, 1955). (5) Natta, G., J. Polymer Sci. 34, 21-46 (1959). (6) Natta, G., Modern Plastics 34, No. 4, 169-82, 261-3 (1956).
Comparison of CrCI3 with TiCI3
In the I/EC Report on “Slide Rules to Ease Your Chores” [IND.ENG.CHEM. 51,30 A (September 1959)] the following captions should have been used :
3OoC. 1 8 hr.
Conv., % 12 25 0 85
97
M = [(g./GMW)1000] Vol.
M is the solution’s molarity, g. the grams of solute, GMW the solute’s gram molecular weight, and Vol. the total volume of solution in milliliters. To express the equation in a linear form, the logarithm of both sides has to be taken, giving this expression: log M = log g.
-
log GMW
-
log Vol.
-
log 103
CorrelatingLatent Heats and Entropies of Vaporization with Temperature In the article on “Correlaring Latent Heats and Entropies of Vaporization with Temperature” [D. F. Othmer and David Zudkevitch, IND. ENG. CHEM. 51, 791 (1959)l in the box at the bottom of the first column reference should have been made to reference (70),not (77).
