Ind. Eng. Chem. Res. 1987, 26, 1750-1753
1750
crease the reaction rate and also increase the possibility of further hydrogenation of the hydroxylamine. Conclusions 1. The results indicate that formation of aniline, which is the principal side reaction in selective synthesis of PHA, occurs in parallel with the formation of PHA. Conversion of PHA into aniline is insignificant until all the nitrobenzene is converted. 2. Addition of MezSO suppresses the above parallel reaction and hence improves the selectivity. 3. The selectivity to PHA decreases with an increase in temperature but is unaffected by hydrogen pressure. 4. Solvent has significant effect on selectivity to PHA. The selectivity shows good correlation with the dielectric constant of solvent. 5. The other substituents on the benzene ring also have a marked effect on rate and selectivity. The rate and selectivity seem to decrease with an increase in electron-releasing effect of the substituent. Nomenclature C N O p = concentration of nitrobenzene at time t , gmol/cm3 k l = rate constant of reaction 1,cm3/[(ntm)(gof catalyst)(s)] k , = rate constant of reaction 2, gmol/[(dtm)(gof catalyst)(s)] k 3 = rate constant of reaction 3, gmoi/[(g of catalyst)(s)] P H I= hydrogen pressure, atm t = time, s Greek Symbols = rate of formation of aniline in part I, gmol/[(g of
YNH,(I)
catalyst)(s)] = rate of formation of aniline in part 11, gmol/ [ (g of catalyst)(s)] YNHOH(I) = rate of formation of PHA in part I, gmol/[(g of catalyst)(s)] +/NHOH(ID = rate of disappearance of I-XA in part 11, gmol/ [ (g of catalyst)(s)] - 7 N 0 2 = rate of disappearance of nitrobenzene, gmol/[(g of catalyst)( s ) ] YNH,(II)
Re&tW NO.PHA, 100-65-2; CsHbNO2, 98-95-3; Pt, 7440-06-4; (CHJZSO, 67-68-5; C&&3, 71-43-2; H3CCOZCH2CH3, 141-78-6; (H,C)ZCHCHzOH, 78-83-1; CHSOH, 67-56-1; H20, 7732-18-5; 2-OzNCsH,C1,88-73-3; 2-O~NCsH4CH3,88-72-2;~ - O ~ N C G H ~ O C H ~ , 91-23-6; P-HONHC,H,OCH,, 35758-76-0; 2-HONHC6H4CH3, 611-22-3; 2-HONHCsHdC1, 10468-16-3; CsH,NHz, 62-53-3.
Literature Cited Aeberli, P.; Houlihan, W. J. J . Org. Chem. 1967, 32, 3211-3214. Barker, G.; Ellis, G. P. J . Chem. SOC.C 1970, 2230-2233. Cavill, G . W. K.; Ford, D. L. J . Chem. SOC.1954, 565-568. Cerveny, L.; RuiiEka, V. Catal. Reu.-Sci. Eng. 1982,24(4),503-566. DiCarlo, F. J. J . Am. Chem. SOC.1944,66, 1420-1421. Fanta, P. E. J . Am. Chem. SOC.1953, 75, 737-738. Hodge, E. B. J . Org. Chem. 1972, 37, 320-321. Kauer, J. C.; Sheppard, W. A. J. Org. Chem. 1967, 32, 3580-3592. Lubs, H. A. The Chemistry of Synthetic Dyes and Pigments; Robert E. Krieger Publishing: New York, 1955. Rajadhyaksha, R. A,; Karwa, S. L. Chem. Eng. Sei. 1986, 41, 1765-1770. Roblin, R. 0.;Winnek, P. S. J. Am. Chem. SOC.1940,62, 1999-2002. Russell, G. A.; Geels, E. J.; Smentowski, F. J.; Chang, K.-Y.; Reynolds, J.; Kaupp, G. J. Am. Chem. SOC.1967,89(15), 3821-3828. Rylander, P. N.; Karpenko, I. M.; Pond, G. R. Ann. N. Y. Acad. Sci. 1970, I72(9), 266-275. Rylander, P. N. Catalytic Hydrogenation in Organic Syntheses; Academic: New York, 1979. Rylander, P. N. In Catalysis in Organic Synthesis 1978; Academic: New York, 1980. Schipper, E.; Chinery, E.; Nichols, J. J . Org. Chem. 1961, 26, 4 145-4 148. Sone, T.; Karikura, M.; Shininkai, S.; Manabe, 0. Chem. Abstr. 1980, 93, 26018. Sugimori, A. Bull. Chem. SOC.Jpn. 1960, 33, 1599-1600. Taya, K. Chem. Commun. 1966, 464-465. Venkataraman, K. The Chemistry of Synthetic Dyes; Academic: New York, 1952; Vol. I. Yale, H. L. J . Org. Chem. 1968, 33, 2382-2385.
Received for reuiew September 4, 1986 Accepted June 1, 1987
Comparison of ASTM Round-Robin Data on Particle Size Using Three Different Methods William H. Flank Union Carbide Corporation, Tarrytown Technical Center, Tarrytown, New York 10591
The Task Group on Particle Size of ASTM Committee D-32 on Catalysts has compiled round-robin data on a single lot of typical equilibrium fluidizable cracking catalyst microspheres. These data were obtained by different methods employing laser light scattering, electroconductive sensing, and a micromesh sieving technique. A total of 18 laboratories participated in all or part of these measurements. Size distribution curves were constructed by plotting particle size vs. cumulative percent finer than the indicated size. In the range 35-100 pm and from about 5 to 95 cumulative 70,the electroconductive sensing method data lie about 5-6 pm below those for the sieving method. T h e laser light scattering data curve lies between the other two curves in the range 35-60 pm and then falls at a progressively greater distance above the other two curves with increasing measured particle size. At 95 cumulative Ti, the laser light scattering curve is about 30 pm above the other two. This technique, then, appears to significantly overstate the size of particles above about 80 pm. Appropriate caution should be used in interpreting or comparing data obtained by this method. The Task Group on Particle Size of ASTM Committee D-32 on Catalysts has been working in the area of particle size measurement for a number of years. In the course of developing consensus standard methods for testing of particle size, round-robin data have been compiled on a single lot of the same material, a typical 0888-5885187/ 2626-1750$01.50/ 0
equilibrium fluidizable catalytic cracking catalyst designated Amoco CCC-408, using three different methods. These methods utilized an electroconductive sensing technique, which can employ instruments like the Coulter Counter and the Elzone system, a laser light scattering technique, which can employ instruments like the L&N 1987
American Chemical Society
Ind. Eng. Chem. Res., Vol. 26, No. 9, 1987 1751 Table I. Results of ASTM Round-Robin Testing of Equilibrium FCC Catalyst by a n Electroconductive Sensing Method" lab code 41 42 43 44 45 46 47 grand av std dev % std dev
(I
vol % median equiv spherical diameter, wm
55.9 54.5 56.4 56.0 54.5
58.0
54.9 54.3 54.5
58.0 57.3 58.2
57.5 57.0 56.5
58.0 57.4 57.6 58.1
58 56 56 57 54.5
lab mean std dev '70 std dev
55.5 0.90 1.62
58.0
54.6 0.31 0.56
57.8 0.47 0.82
57.0 0.50 0.88
57.8 0.33 0.57
56.3 1.30 2.32
56.7 0.64 1.13
1.30
2.30
Within-lab repeatability, 2s ?&,f2.370; between-lab reproducibility, 2s 70, f4.670.
Table 11. Results of ASTM Round-Robin Testing of Equilibrium FCC Catalyst by a Laser Light Scattering Method" lab code 51 52 53 54 55 56 57 58 59 grand av std dev 70std dev Means of Five Runs per Set 63.3 63.9 65.9 65.5 63.6 63.3 64.6 65.0 vol '70 median 65.8 64.0 66.1 66.7 equiv spherical 65.3 63.4 64.6 62.5 61.6 63.5 diameter, wm 66.1 63.8 64.7 63.5 64.0 66.6 65.8 62.8 63.3 lab mean std dev % std dev
65.7 0.40 0.61
Within-lab repeatability,
63.9 0.61 0.95
64.8 0.21 0.32
63.1 0.53 0.84
64.0 0.06 0.09
66.2 0.36 0.54
66.0 0.62 0.94
62.7 1.01 1.61
63.4 0.12 0.19
64.4 0.44 0.68
1.32
2s 70,f1.4%; between-lab reproducibility, 2s 70,f4.1%.
Table 111. Results of ASTM Round-Robin Testing of Equilibrium FCC Catalyst by a Dry Sieving Method" lab code 61 62 63 64 65 66 67 grand av std dev interpolated wt % 67.0 64.0 63.0 67.7 63.4 62.0 66.0 63.0 62.9 67.3 63.5 63.0 median diameter, wm 66.0 63.0 62.5 67.8 63.9 lab mean std dev % std dev (I
2.05
66.3 0.58 0.87
64.0 (av)
63.3 0.58 0.91
62.8 0.26 0.42
67.6 0.26 0.39
63.6 0.26 0.42
62.5
64.3 0.39 0.60
1.91
70 std dev
2.98
Within-lab repeatability, 2 s %, f 1.2%; between-lab reproducibility, 2s %, f 6.0%.
Microtrac and the Cilas Granulometer, and a dry micromesh sieving technique. The methods are published in A n n u a l Book Of A S T M Standards, Vol. 5.03, under the designations D-4438, D-4464, and D-4513, respectively. More detailed descriptions of the techniques involved can be found in general texts describing particle size measurement, e.g., Allen (1981). All of the test procedures follow the basic recommendations made by the manufacturers of the equipment used for the various methods, only adding cautions or steps appropriate to a catalyst sample, such as the one employed in the round-robin testing. Uniform sample handling, calibration, and data presentation methods are also recommended in the test procedures.
Results Seven labs reported results for the median equivalent spherical diameter of the equilibrium FCC catalyst using the electroconductive sensing method. These are shown in Table I. The means and standard deviations derived from the data are also shown, and the calculated within-lab repeatability of *2.3% and between-lab reproducibility of rt4.670 are listed. These quantities are defined as an interval extending two relative standard deviations on either side of the mean and encompassing 95% of the expected results. For the laser light scattering method, nine labs contributed to the data shown in Table 11. Again, the means and standard deviations derived from the data are shown, and the calculated within-lab repeatability of f1.470 and between-lab reproducibility of *4.1% are listed.
Table IV. Labs Participating i n ASTM Round-Robin Testing of Equilibrium FCC Catalyst method electroconductive sensing laser light scattering dry sieving AKZO Chemie Conoco AKZO Chemie Coulter Electronics Davison Chemical Cities Service Engelhard-Menlo Engelhard-Menlo EngelhardPark, N J Park, NJ Menlo Park, NJ Engelhard-Newark, L&N-Largo, FL Haldor Topsoe NJ Mallinckrodt L&N-Houston, T X Harshaw Union Carbide Mallinckrodt Union Carbide Union Oil UOP Monsanto Norton Co. Shell Development
Data were reported from seven labs using the dry sieving method and employing several different types of screens and shaking devices. These results are shown in Table 111, which also includes means, standard deviations, and calculated within-lab repeatability and between-lab reproducibility. These latter figures are *1.2% and *6.0%, respectively, and indicate that operating procedures within a lab contribute little to data variability but that differences between labs are much larger. My own experience suggests that equipment differences, such as screen variability, may be rather large. One way to overcome this, of course, is to use smoothed plots of the data. While Tables 1-111 list code numbers for the participating labs, the names of the labs contributing data to each of the three methods are shown as groups in alphabetical
1752 Ind. Eng. Chem. Res., Vol. 26, No. 9, 1987 Table V. Particle Size Distribution Data from Four Labs Using an Electroconductive Sensing Method' lab code size, p m 43 46 47 45 mean std dev 0.2 0.30 0.0 0.0 10 0.6 0.0 0.5 0.71 0.6 0.0 0.0 20 1.5 2.9 1.16 2.0 4.3 30 3.4 1.9 12.9 2.70 14.5 13.1 40 14.9 9.0 31.8 3.48 33.5 32.0 50 34.7 26.8 53.6 4.03 57.8 53.0 48.3 60 55.2 70.7 3.85 73.5 71.8 70 72.4 65.0 1.57 84.7 84.5 84.2 83.2 80 86.9 92.1 1.92 91.8 92.7 89.7 90 94.3 97.0 0.53 96.3 97.0 97.0 100 97.6 98.5 98.4 0.32 98.0 110 98.6 99.9 99.9 150 99.8 Data are av 70 finer than the indicated size.
order in Table IV. Several instances are evident where labs of the same company from different locations participated independently. The data from such labs were treated as if they came from independent sources. While median diameter data were compiled and used to develop the repeatability and reproducibility bounds for the various methods, as shown earlier in Tables 1-111, the participating labs also supplied a considerable amount of particle size distribution data. These distribution data allow more detailed comparisons to be made. The ways in which these data have been handled are described below. The distribution data supplied by four labs using the electroconductive sensing technique have been tabulated in Table V. The numbers listed represent the averages for two to four runs for each entry. The mean and standard deviation for all four of the labs for the average
percent finer than each indicated size is tabulated for the data set. These last values were used in the construction of curves which will be discussed later. Computer reprocessing of the distribution data supplied by the nine labs using the laser light scattering technique was performed by Dr. Philip Plantz of Leeds and Northrup to provide a complete set of equal-interval distribution data, since some concern existed regarding the width of the measuring channels, particularly at the larger particle sizes. These results are tabulated in Table VI, and the average percent finer than each indicated size for each lab represents the mean of five readings on each of three samples. The overall mean and standard deviation at each uniform size increment are tabulated, and these data were used in the construction of curves which will be described later. The dry sieving data that were reported from seven labs, each of whom ran the sample from 2 to 4 times, were plotted, and interpolated distribution values were taken from the curves as tabulated in Table VII. These points, taken from each lab's mean curve, were then averaged to obtain an overall mean and standard deviation for each size increment, which were then used in plotting size distribution curves.
Discussion Two sets of curves can be compared. Distribution data from each of the three methods are plotted in Figure 1. They were supplied in the cases of electroconductive sensing and laser light scattering by instrument manufacturers' labs. The dry sieving curve is a seven-lab average. It can be seen that two of the curves parallel each other over essentially the entire range, with the dry sieving
Table VI. Equal-Interval Particle Size Distribution Data from Nine Labs Using a lab code size, pm 51 52 53 54 55 56 57 10 0.2 0.2 0.3 0.3 0.3 0.1 0.3 0.7 1.2 1.1 1.2 0.8 1.3 20 0.7 3.2 4.1 3.5 4.4 4.0 30 3.1 3.0 10.3 10.7 13.0 11.4 40 11.1 10.5 11.9 22.5 25.0 21.6 27.0 24.1 24.8 50 24.4 39.7 38.6 44.1 42.7 43.0 41.8 60 41.1 53.5 56.3 53.2 58.4 70 53.6 55.2 55.1 66.3 67.4 72.1 68.5 67.3 80 64.5 64.8 78.3 79.8 80.7 84.8 73.7 78.7 90 74.8 84.9 83.0 89.3 84.6 84.1 80.5 78.7 100 88.8 87.6 93.5 89.3 83.6 89.4 110 86.0 91.9 93.7 92.6 97.6 88.3 94.4 91.3 120 94.7 96.3 95.0 99.6 91.6 97.2 130 94.6 96.0 96.2 99.7 97.2 93.6 97.9 140 95.9 97.3 97.2 99.8 98.0 95.5 98.5 150 97.1 98.4 98.3 99.9 98.8 97.3 99.1 160 98.3 100 99.6 99.4 99.4 99.7 99.4 99.0 170
Laser Light Scattering Method" 58 1.3 2.5 5.1 14.2 28.3 45.7 58.7 70.3 80.9 85.5 89.9 94.1 96.6 97.4 98.2 98.9 99.6
59 0.3 0.9 3.6 11.6 25.1 43.4 57.0 69.0 80.0 84.3 88.4 92.3 94.8 96.0 97.2 98.3 99.4
mean 0.4 1.2 3.8 11.6 24.8 42.2 55.7 67.8 79.1 83.9 88.5 92.9 95.6 96.7 97.6 98.6 99.5
std dev 0.36 0.55 0.69 1.26 2.04 2.20 2.07 2.48 3.32 3.02 2.73 2.54 2.20 1.68 1.18 0.71 0.27
"Data are av 70 finer than the indicated size.
Table VII. Interpolated Particle Size Distribution Data from Seven Labs Using a Dry Sieving Method" lab code size, p m 61 62 63 64 65 66 67 mean 0.5 0.3 0.0 0.3 20 0.0 0.7 1.9 3.2 1.8 2.8 30 1.3 5.8 6.1 9.0 9.7 7.8 40 2.1 13.3 8.1 6.2 17.9 27.5 26.2 21.9 50 15.3 25.9 22.2 18.3 60 34.0 46.4 43.5 40.0 37.2 46.6 43.8 41.6 61.0 60.6 56.4 61.4 70 54.8 67.2 63.0 60.3 78.1 76.6 80 73.0 80.1 78.5 76.4 74.8 75.3 88.7 87.7 90 86.0 89.1 88.2 87.2 87.1 87.9 94.1 95.1 95.1 94.8 100 93.7 95.6 95.0 97.6 96.4 96.1 96.4 96.7 105 95.0 "Data are av % finer than the indicated size.
std dev 0.31 1.82 3.50 4.80 4.76 4.11 2.45 1.06 0.71 0.94
Ind. Eng. Chem. Res., Vol. 26, No. 9, 1987 1753
160
I
Microtrac, L 8 N , Largo, FIB.Average of 6 Runs
$
160
-
140
-
SYMBOL j LaserLighlScattering
-
- Electroconductive
- Nine. lab average for five readings on each 01 three samples. - Four- lab average for two to
3
- Dry Sieving
- Seven-lab
Sensing
120-
W
Coulter Counter, Couker €lac. tronics-Average of 3 Runs
0
T
3 +3
four runs each. average.
- i one std. deviation for Inter. lab average.
Dry Sieving, Average of 7 Labs.
8ol 80
0 0
I
I
I
1
I
I
I
I
I
10
20
i
30
40 50 60 70 CUMULATIVE PERCENT
80
90
100
Figure 2. Comparison of particle size distribution data on equilibrium FCC catalyst.
techniques. The laser light scattering method, then, might be said to significantly overstate the size of particles above about 80 pm, compared to the other two methods tested, and appropriate caution should be used in interpreting or comparing such data. It may be possible to minimize the bias in the light scattering data by careful attention to avoidance of coincidence effects by, e.g., sample dilution and dispersion and by use of limited size intervals. These are cautions that are applicable to the electroconductive sensing method as well, and the use of limited size intervals is certainly desirable in the dry sieving method. One further means for improving the laser light scattering results is to use computer reprocessing to compensate for the inherent bias in the raw data. However, decreasing resolution, related to the decreasing angle of diffraction of larger particles, limits the improvement in bias and precision attainable with larger particles by use of a finite number of limited size intervals. When the width of the measuring channels was not constrained, the deviations were even more pronounced.
Literature Cited Allen, T. Particle Size Measurement, 3rd ed.; Chapman and Hall: London, 1981; Chapters 13 and 20. Annual Book Of ASTM Standards; ASTM: Philadelphia; Vol. 5.03, Standards D-4438-85, D-4464-85, and D-4513-85.
Received for review September 9, 1986 Accepted May 19, 1987
