THE CATALYTIC ACTIVITY O F CARBONS FROM AROMATIC HYDROCARBONS AND SOME DERIVATIVES BY WAIJTER FARMER AND JAMES BRIERLEY FlRTH
A study of the catalytic activity of cane sugar carbon relative do hydrogen peroxide' showed that the activity is influenced by the previous treatment of the carbon. Subsequently, it was shown2 that the influence of the previous trpatment of the carbon upon the catalytic activity with reference to hydrogen peroxide manifested itself in the case of carbons prepared from ten carbohydrates other than cane sugar. The same authors3 not only adduced evidence t'o show that the rate and extent of the catalytic decomposition of aqueous hydrogen peroxide by pure sugar carbon is increased with rise of temperature, but also showed that the activity of the carbon decays during the reaction. This phenomenon was made clear when it was shown that the fundamental difference in the activity of the carbons derived from cahohydrates manifested itself in the initial activity. This activity rapidly fell off after the first few minutes, ultimately becoming very slight, notwithstanding that the solution contained a considerable quantity of undecomposed hydrogen peroxide. In the same paper (1oc.cit.) experiments were described in which cellulose carbon, after iodine treatment, exhibited a remarkable increase in the initial activity towards aqueous hydrogen peroxide, the concentration of the soh tion and the conditions of temperature remaining constant for all experiments. Thus, after heat treatment in a vacuum in a quartz flask at 6ooOC.. one gram of celliilose rarbon, in contact with z5rc. of hydrogen peroxide containing 3 1 1 . 2 ~ of ~ . available oxygen, liberated 1 8 . 6 5 ~of ~ .oxygen in ,z, minutes. After iodine treatment, one gram of carbon, in contact with 25cc. of the hydrogen peroxide, liberated 7 6 . 4 ~ of ~ .oxygen in the same time, all volumes being measured a t X.T.P. Although inulin and rice starch carbons showed considerable increases in activity after iodine treatment, potato starch and wheat starch carbons were not appreciably affected. None of the carbons investigated exhibited an increase in the initial activity comparablc with that of cellulose carbon. The present investigation on the catalytic activity of carbons derived from aromatic compounds was, therefore, undertaken in order to ascertain the differences in the initial activity (if any) exhibited by the various carbons; to study the effects of iodine treatment on the relative magnitudes of those differences; and to determine the influence (if any) of the presence of halogen, nitrogen, or sulphur in the original compound. 1 2
Firth: J. SOC.Chem. Ind. 42, 242T (1923). Firth and Watson: J. SOC.Chem. Ind. 42, 371T (1923). J. Chem. SOC. 123, 1750 (192.1).
*
I’ATALYTIC ACTIVITY O F CARBONS
1x37
Experimental N/Io-solutions of iodine in chloroform prepared as in the preceding study were used in all experiments. An aqueous solution of hydrogen peroxide containing 3 z I .gcc. of available oxygen (measured at N.T.P.) was employed in all cases. Two series of experiments were carried out in which the carbon, prior to treatment with the hydrogen peroxide solution, was activated by one of the following methods:-
(I) The carbon was heated iu a vacuum, in a quartz tube, at 9oo0C’., for two hours, and then allowed to cool in a vacuum.
(11) The carbon previously treated as in (I) was al!owed to stand in contact with a N/IO solution of iodine in chloroform, in the proportion of one gram of the carbon to zgcc. of the standard iodine solution. The carbon was filtered off after 24 hours, transferred to an evaporating dish, and gently heated until iodine vapours were no longer evolved. It was then digested with dcoholic potash, filtered off, washed with boiling distilled water until the filtrat,e remained clear on addition of silver nitrate solution, then washed with alcohol, dried, and finally heated as in (I) above, prior to treatment with the hydrogen peroxide solution. One gram of carbon was carefully weighed out into a small flask; Z ~ L ‘ C . of the hydrogen peroxide solution was measured out into a flat-bottomed tube, and the tube placed inside the flask. The flask WRS then connected with a gas burette, and the hydrogen peroxide brought into contact with the carbon by tilting thc flask. Accumulation of gas in the liquid was prevented by rapid agitation. The experiments were all carried out a t 18’C. The volumes of oxygen liberated were recorded a t intervals ranging from thirty seconds to half an hour according to the velocity and stage of the reaction. A series of blank experiments with hydrogen peroxide alone gave an average yield of 0.2gcc. of oxygen in 3 hours. The volumes of oxygen recorded were corrected to N.T.P., and the Table given below shows results typical of all observed throughout the experiments. The reaetion velocity coefficients corresponding to the corrected volumes of oxygen observed a t the several stages of the reaction are included in the Table, and are calculated from the equation for a unimolecular surface reaction dx/dt =K(n-x) to the Naperian base, with the minute as unit of time. The complete results of all observations for the experiments of series I and I1 are represented graphically in Figs. I and z respectively, whilst a summary of results with the corresponding velocity coefficients is given in the following table. (Tab!? I).
I 138
WALTER FARMER AND JAMES BRIERLEY FIRTH
6 FTG. 1-Carbon
not Treated with Iodine
I Metanitraniline; I1 diphenylamine; 111 thiocarbanilide IV Paratoluidine; V anthracene; VI aniline; VI1 metadinitrobenzene; +I11 naphthalene; IX pyridine. X alphana hthylamine; XI monochlorobenzene; XI1 xylene and salicyiic acid; X& benzene, turpentine and camphor; XIV toluene and benzoic acid; XV phenol, alpha and beta-naphthol and a
resorcinol.
CATALYTIC ACTIVITY OF CARBONS
300 I
I
FIG s-Carbon Treated with Iodine I Diphenylamine; I1 thiocarbanilide; I11 aniline; IV alphanaphthylamine; V anthracene, metanitraniline and paratoluidine; VI pyridine; VI1 metadinitrobenzene; VI11 resorcinol; I X salicylic acid; X Turpentine; X I benzene; XI1 camphor; XI11 benzoic acid; XIV naphthalene. XV beta-napthol; XVI monochlorobeneene; XVII phenol and alpha-naphthol; XVIII xylene; XIX toluene.
I 140
WALTER FARMER AND JAMES BRIERLEY FIRTH
TABLE I Time in Minutes
Heated in vacuum at 900" Volume of KXIO~ Oxygen(cc.)
Iodine treatment Volume of KX 103 Oxygen (cc.)
BENZENE
3 6 9 30 60
0.8 1.5
1.9 4.5 7,3
I20
12.5
I80 240
17.4 21.8
3 6 9 30 60
1.7
0.400 0.350 0.289 0.203
0.167 0 . I43 0 . I34 0.127
10.4 15.4 19.4 42.6 67.4
4.767 3.567 3 . 0 1I
102.7
2.060 1.703 1.393
131.8 154.4
1.273 I . 184
I.8
0.800 0.467 0.411 0.273
TOLUENE
I20 I80
240
1.8 2.1
4.2
7.0 11.8 14.2 17.6
0.767 0.400 0.311 0.190 0.160 0 . I35 0.109
7 5 .I
0.
22.1
0.172
0.I02
27.2
0.160
2.1
2.7
6.0 9.4
0.215
I74
XYLENE
3 6 9 30 60
3.4
I ' 567
3.5
I . 600
5.0
I33 0.922 0.413 0.263 0.204
5.7
I .300 I . IO0
6.I 9.1 11.5
I20
17.6
I80 240
22.5
27.9
1
'
0 . I75 0.164
7.2 17.0
24.0 35.4 46.9 58.8
0.787 0.562 0.422 0.381 0.366
NAPHTHALENE
3
6 9
30
60 I20
I80 2 40
8.3
12.9 16.6 34.5 51.1 72.I
91.2 106.5
3.800 2.950 2.556 1.643 1.253
0.919 0.805 0.728
10.6 15.6 20.0
37.8 54.8 76.7 95.5 112.7
3.867 3.600 3.267 1.810 1.353 0.987 0.856 0.781
ANTHRACENE
6
10.9 17.5
9
22.2
3 30
60
59.2 88.6
5.000
4.050 3.455 2.947 2.333
I20
121.2
1.713
I80
145.5 165.6
1.454 1.310
240
73 . o 119.0 143.0 240.9 274.0 286.I 291.4 29s.8
37.267 33.450 28.400 0.030 13.842 7.985 5 * 714 4.572
I 141
CATALYTIC ACTIVITY O F CARBONS
TABLE I-Continued Time in Minutes
Heated in vacuum at goo" .Volume of KXio3 Oxygen(cc.)
Iodine treatment Volume of K X 10s Oxygen (cc.)
MONOCHLOROBENZENE
3 6 9 30 60 I20
I80 240
4.5 5.8 7.3 12.8 19.5 30.4 40.2 51.4
2.033 1.317 1.111
0.587 0.453 0.360 0.322 0.315
5.2 7.2
8.8 19.5 30.9 44.6 57.6 70.4
2.367 I .650 1 333 0.907 0.732 0.541 0.476 0.447 9
METADINITROBENZENE
3 6 9 30 60
10.4
180
14.8 18.9 37.1 53 * 5 80.6 102.3
2 40
122.8
3 6 9 30 60
12.3 19.7 24.8
I20
101.3
I20
4.767 3.417 2.922
1.777 1.318 1.045 0.924 0.870
170.6 216.9 229.5 236.2
11.833 9.800 9.089 6.890 5.477 4.064 3.019 2.401
99.1 148.3 178. I 264.0 283.0 291 ' 5 294.9 296.3
53.333 44.783 38'967 24.917 15.362 8.584 6.013 4.608
87.9 134.5 166.9 246.3 273.6 286.8 291 . 3 293.6
46 * 233 39.233 35.333 21.033 13.782 8.058 5.707 4.423
91.8 140. I 175.9 251.6 264.4 275.5 279.4 281.5
48.667 41.433 38.222 24.327 12.510 7.037 4.905 3.771
25.2
40.7 55.2 121.8
ANILINE
50. I
72.7
I80
127.0
240
I49 * 9
3 6 9 30 60
6.I 9.8 13.9 41.5 75.9 118.9 148. I 168.8
5.633 4.583 3.878 2.453 1.855 1.370 1.213 I . 136 PARATOLUIDINE
I20
I80 2 40
2.767 2.233 2 * I33 2 .ooo
1.948 I . 671 1.490 1.348 ALPHANAPHTHYLAMINE
3 6 9 30 60 I20
I80 240
6.9 5 13.6 28.5 39.8 59.9 77.4 92.9 IO.
3.167 2.400 2.089 1.343 0.957 0.747 0.664 0.617
1142
WALTER FARMER AND JAMES BRIERLEY FIRTH
TABLE I-Continued Time in Minutes
Heafed in vacuum at gooo Volume of Oxygen(cc. )
KXIO~
Iodine treatment
Volume of Oxygen (cc.)
'
K X IO'
METANITRANILINE
3 6 9 30 60 I20
I80 240
63.9 88.9 106.9 I93 - 0 242.8 277.3 282.9 286.7
32.IOO 23'433 19.511 13.277 IO.187 7.182 5.114 4.023
34.4 50.8 67.7 142.0 196.9 239.5
16.367 12,450 11.411 8.437 5.862 4.945 3.627 2.876
75.0
114.6 147.0 246.0 276.2 286.3 289.9 293.4
38.467 31.900 29.489 2 0 * 977 14.185 8.006 5.597 4.410
130.9 180.7 224.8 289.4 293.8 295.9 297 . o 298.5
59.883 57.978 33.357 17.745 9.158 6.211 4.773
149.4 208.7 237.9
go.500 75.833 65.000
275.7
28.210
DIPHENYLAMINE
3 6 9 30 60 I20
I80 240
250.0
255.9
7 5 * 700
THIO CARBANILlDE
I80
17.8 29.2 38.9 84.9 126.2 175.7 294.7
2 40
221.8
3
6 9
30
60 I20
8.267 6.goo 6.233 4.440 3.610 2.863 2.443 2.119
278.6 281.5 284.7 289.0
14.578 7.543 5.230 4.I47
PHENOL
3 6 9 30
60
1.3 1.5 1.7
3.0 4.8 7.4
I20 I80
11.0
240
14.I
3 6 9
1.1
0.600 0.350 0.256 0.137 0.108 0.085 0.084 0.081
3.6 6.0 7.3 20.0
29.8 44.0 55.9 $6.0
1 * 633 1 a367 1.111
0.930 0.705 0.533 0.461 0.416
ALPHANAPHTHOL
30
60
I20
I80
240
1.6 2.1
3.4 5.0 7.5
10.4 13. o
0.533 0.367 0.311 0 . I57 0.113
0.086 0.079 0.075
3.8 5.8 7.1
15.7 25.3 40.I 55.1
68.4
I . 700 1.317 I .078
0.727 0.593 0.483 0.453 0.433
CATALYTIC ACTIVITY OF CARBONS
TABLE
Time in Minutes
I-Continued
Heated in iqacuum at 900" Volume of XXIoa Oxypen(cc.)
Iodine treatment Volume of KX 108 Oxygen(cc.)
BETANAPHTHOL
3 6
9
30 60 I20
1.2 1.5
1.8 2.7 4.2
7.2
180
IO.2
240
13.1
0.567 0.350 0.267 0.123 0.095 0.083 0.078 0.075
6.7 11.5
15.4
3.067 2.633 2.378 1.567
33.0 49.9 75.6 94.1 111.8
0.970 0.830 0.773
24.6 39.0 49.4 96.3 134.3 178.3 205.3
11.533 0.367 9.044 5.153 3.915 2.928 2.455
226.0
2.I97
I.222
RESORCINOL
3 6 9 30 60 I20
180 240
1.1
1.6 2.0
3.0 4.6 7.4 10.4 13.I
0.533 0.367 0.300 0 . I37 0.105 0.085
0.079 0.075 BENZOIC ACID
3
6 9
30 60 I20
180 240
1.0
1.9
2.3 4.3 5.8 9.3 12.5 15.8
0,467 0.433 0.344 0 .I93 0.132 -0.106 0.096 0.091
7.7 12.4
16.3 33.9 53.7 81.1
3 533 2.850 2.544 1.613 1.323 1 .os3 '
102.I I21 . o
0.922
19.0 30.4 39.1 79.1 116.2 172.I 211.0 239.7
8.833 7.200 6.267 4* 090 3.247 2 * 773 2.577 2.477 9.500 7 ' 167 5.822 3 653
0.855
SALICYLIC ACID
3
1.5
0.700
2.0
6 9
2.6
0.450 0.400
30 60
5.7
0.260
I20 I80
9.3 15.9
0.212
0.183 0 . I77 0.166
240
2'2. 7 28.2
3
2.2
I . 000
20.4
6 9 30
2.5 3.5
60
4.8 7.0
0.567 0.533 0.217
I20
12.0
0.138
I80
15.1
240
19.9
0.116 0.115
30.3 36.5 71.7 108.4 162.3 200.7 225.0
TURPENTINE
0.160
2.977 2 * 544 2.362 2.178
.
WALTER FARMER AND JAMES BRIERLEY FIRTH
TABLE I-Continued Time in Minutes
Heated in vacuum at goo" Volume of Oxygen(cc.)
K X 108
Iodine treatment Volume of K X 108 Oxygen (cc.)
CAMPHOR
3 6 9 30 60 I20
180 240
2.1
0.933
10.5
3.3 3.7
0.750
16.4
7* o 9.3 14.4 18.6 23.0
0.556 0.320 0.212
0.167 0.I44 0.I35
21.1
43.7 63.8 90.6 112.7
134.3
4.800 3.800 3 278 2.113 I . 602 I . 198 1.041 0,979 '
PYRIDINE
3 6 9 30 60 I20
180 240
6.6 10.4 14.0 30.9 44.4 65.7 86.4 104.0
3 * 033 2.383 2.156 1.463 1.075
0.828 0.755 0.707
49.2 82.8 113.2
214.2 259.7 282.0 288.2 292.8
24.033 21.550
944 15.887 11.937 7 * 588 5.471 4.372
20*
Discussion of Results After heating in a vacuum for two hours, a t goo°C., the different carbons exhibit a graded variation in activity relative to hydrogen peroxide. This is most marked in the case of metanitraniline and diphenylamine carbons, and least for the carbons derived from phenol, alpha-, and beta-naphthol, and resorcinol, these showing approximately similar activity. Cf the carbons obtained from aromatic hydrocarbons, that from anthracene shows the highest activity, and those from benzene and turpentine the least. Pyridine carbon shows an activity considerably higher than benzene carbon, and only slightly less than that of naphthalene carbon. The activity of monochlorobenzene carbon is higher than benzene carbon, and the same is trrueof thiocarbanilide carbon with respect to carbon from aniline. An interesting feature of the results is that, in addition to the cases already mentioned, carbons derived from the following pairs of substances show similar catalytic activity :-(a) toluene and benzoic acid, (b) xylene and salicylic acid, ( c ) anthracene and paratoluidine, (d) turpentine and camphor. Whilst, in this series of experiments, carbons derived from amine bases show the highest activity, and those from phenolic substances the least activity, there is not sufficient evidence to ehow to what extent (if any) the activity is enhanced by nitrogen on the one hand, and diminished by oxygen on the other; or, indeed, whether any influence on the catalytic activity of the carborn is to be attributed to the elements themselves, or to the amino-, and hydroxyl-groups in which they occur.
CATALYTIC ACTIVITY O F CARBONS
1145
The results of the second series of experiments indicate that previous sorption of iodine produces a marked increase in the activity of all the carbons, with the exception of toluene and naphthalene carbons Very considerable increases in activity are exhibited by the carbons obtained from aniline, anthracene, paratoluidine, thiocnrbanilide, and alphanaphthylamine. Of the carbons derived from phenolic substances, that from resorcinol shows the highest activity, while phenol, and alpha-naphthol carbons show the least activity. Salicylic acid carbon shows a much higher activity than benzoic acid carbon, and the same may be said of turpentine carbon with reference to camphor carbon, and of benzene carbon with respect to monochlorobenzene carbon. With the exception of anthracene carbon, the carbons showing the highest catalytic activity are derived from substances containing basic nitrogen, with sulphur in addition, in the case of carbon from thiocarhanilide. From a study of the catalytic decomposition of hydrogen peroxide by blood charcoal, Firth and Watson1 showed that the effect of the various methods of activation is confined to the initial reaction. The blood charcoal, purified by digestion for a month with aqua regia, and subsequent washing with boiling distilled water until the filtrate showed no indication of iron with potassium sulphocyanide solution, was activated by one of the following methods:-(I) by heat treatment at 6o0°c.;(II) by heat treatment a t 9ooOC.: (111) by heat treatment as in (I), iodine treatment, and then heat treatment as in (I) : (IV) by heat treatment as in (II),iodine treatment, and then heat treatment as in (11). Jn each experiment, 25cc. of hydrogen peroxide solution containing 2 4 2 . 5 ~ of ~ .available oxygen (measured at N.T.P.) was used with 0.25 gram of the activated charcoal as catalyst. An examination of the results obtained showed that during the first thirty seconds, the percentage of hydrogen peroxide decomposed by the Charcoals activated by methods I., IT., HI., and IV., respectively, was 9.32, 9.68, 17.1, and 25.13, whilst, after twelve minutes the values were very similar in all cases. The corresponding velocity constants for the first thirty seconds were 85.00, 96.40, 162.60, and 258.80, respectively. After twelve minutes they were 37.94, 41.33, 41.51, and 42.13, whilst after 60 minutes, when 74.5 per cent. of the hydrogen peroxide had been decomposed by each charcoal, they were reduced to approximately the same value, the respective constants being 9-33>9.56, 9.60, and 9.91. The velocity coefficients for unactivated blood charcoal were 10.2 for thirty seconds, and 9.4 for one minute. From these results the authors concluded that the extent of the decomposition is not determined by the initial activity, because charcoals of widely different initial activities approach similar values after about thirty minutes. The authors, therefore, put forward the view that the catalytic activity of the blood charcoal is of two types, one, a very rapid activity which decays Trans. Faraday SOC. 19 111, No. 57 (1924).
I 146
WALTER FARMER AND JAMES BRIERLEY FIRTH
after a few minutes, and the other a much slower activity which persists for a much longer period. Both forms may be increased by activation methods. These two types of activity have been termed, alpha, and beta activity, respectively. Unactivated blood charcoal does not show alpha activity. Provided that the alpha activity is not sufficient to bring about complete decomposition of a hydrogen peroxide solution of given strength, it is the beta activity which determines the limit of decomposition. I n the present investigation, a study of the results obtained from the experiments of series IJ shows that in their activity towards hydrogen peroxide the various carbons may be arranged in three groups:-(a) carbons exhibiting a rapid initial, or alpha activity, followed by a very slow beta activity: (b) carbons showing little or no alpha activity, and whose activity is almost entirely of the beta type: (e) carbons possessing the two types of activity without the pronounced demarkation between the alpha and beta activities, as exhibited in (a). With the exception of metanitraniline, naphthalene, and toluene carbons, the combined effect of the alpha and beta types of activity is to increase the percentage decomposition of the hydrogen peroxide solution, and this is clearly shown by a comparison of the velocity coefficients for the carbons activated by the methods employed in the experiments of series I and 11. In no case, however, is there complete decomposition of the hydrogen peroxide in a reasonable time.
Summary I. The carbons derived from various aromatic compounds show a graded activity relative to hydrogen peroxide when activated by heat treatment in a vacuum, a t goo°C. The activity of the majority of the carbons is considerably increased 2. by previous sorption of iodine from chloroform solution. 3 . The carbons exhibiting the highest initial activity are, in the majority of cases, derived from compounds containing basic nitrogen.
University College, Noltingham.
