1466
H. A. DEWHURST
Vol. 61
RADIATION CHEMISTRY OF ORGANIC COMPOUNDS. I. n-ALKANE LIQUIDS BY H. A. DEWHURST General Electric Research Laboratory, Schenectadv, N . Y. Received June IO. lO6Y
A series of n-alkane liquids, pentane to hexadecane, have been irradiated with 800 kvp. electrons. The hydrogen yield, G(H2) E 4.9,was found to be independent of the length of the carbon atom chain, whereas the methane yield decreased with increase in the length of the carbon atom chain. Infrared analysis has shown that the unsaturation produced is largely trans vinylene with a smaller amount of vinyl. Gas-liquid partition chromatography has shown that three primary product groups are formed: a dimer group, an intermediate group between the dimer and parent, and degradation group. These results show that C-C bond scission is an important process, contrary to conclusions based only on gas analysis.
1. Introduction Radiation chemical studies of the saturated aliphatic hydrocarbons have been concerned mainly with the production of gaseous products with relatively little attention paid to the liquid products. The early gas phase studies of Lind and co-workers’ established that the gaseous products consisted mainly of hydrogen with small amounts of paraffin hydrocarbons. The liquid products, although largely unidentified, were found to contain a high proportion of unsaturated hydrocarbons. Later work by Honig and Sheppard2 showed that the liquid products contained a wide range of moIecular weights (cross-linking), and obtained evidence for the presence of unsaturated products. The radiolysis of hydrocarbon liquids by Schoepfle and Fellowsa demonstrated that hydrogen was the major component of the gaseous products. Recently Flanagan, Hochanadel and Penneman4 determined the total gas yields as well as the yield of “polymer” which remained after evaporation of the reactant. No information was given concerning the nature of this polymer. Breger6 studied the a-particle radiolysis of hexadecane and octacosane and found the gaseous products to consist of 95y0 hydrogen and 5% gaseous hydrocarbons. He found that non-volatile hydrocarbons of lower molecular weight than the original could not be detected. The crosslinking and degradation of some n-paraffins has been examined by Charlesbyc in connection with the effect of high energy radiation on poIyethylene polymers. The very high doses used by Charlesby preclude any conclusion pertaining to the primary radiation processes. Krenz7 has made a study of the radiolysis of n-hexane and n-hexane-anthracene solutions. He found that an unsaturated hydrocarbon with approximately the same volatility as n-hexane was formed. The formation of cross-links and unsaturation in octacosane has been thoroughly examined by Miller, et aL8 Several workersg have used a reactive solute to (1) S. C. Lind and D. C. Bardwell, J . A m . Chem. Soc., 48, 2335 (1926). (’2) R. E.Honig and C. W.Sheppard, THISJOURNAL, 50,119 (1946). (3) C. 8. Schoepfle and C. H. Fellows, Ind. Eng. Chem., 23, 1396 (1931). (4) See M.Burton, THIBJOURNAL, 51, 611 (1947). (5) I. A. Breger, ibid., 62, 551 (1948). (6) (a) A. Charlesby, Proc. Roy. SOC.(London), A222, GO (1954); (b) A. Charlesby, Radiation Research, 3, 96 (1955). (7) F. H.Krenz, Nature, 176, 1113 (1955). (8) A. A. Miller, E. J. Lawton and J. S. Balwit. THIs JOURNAL, 60, 599 (1956).
study the primary radiochemical reactions (scavenger method) in hydrocarbon liquids. The solute is assumed t o be an efficient radical trap. From a study of the kinetics of the solute reaction, the socalled radical yieldlo has been calculated for a variety of hydrocarbon liquids. With the exception of the (radio) iodine method, radical production studies have not identified the nature of the free radicals and therefore do not give any indication of the products to be expected in the pure liquid. This paper is concerned with the radiolysis of a series of normal alkane liquids. The purpose of this work was to examine all the products (gas as well as liquid) in order to understand better the mechanisms of radiation-induced reactions in pure alkane liquids. 2.
Experimental
2.1 Materials.-The
liquid hydrocarbons used in this investigation were as follows: n-pentane, n-hexane, n-he tane, n-octane and n-nonane (Phillips pure grade, 99 mole minimum impurity); n-decane and n-dodecane (Matheson Co .); n-hexadecane (Humphrey and Wilkins); cyclohexane (Eastman Kodak spectro grade). The cyclohexane was used as received. The other hydrocarbons11 had been further purified, by the conventional sulfuric acid method, in connection with other studies in this Laboratory.la 2.2 Irradiation.-The high energy electron source used was the General Electric Research Laboratory 800 kvp. resonant transformer unit.’a Two kinds of irradiation cells were used in this investigation. Thin window glass (Pyrex) cells, similar to those described by Hentz and Burton,” were used for the determination of gaseous products. Each cell, approximate volume 1-3 ml., was equipped with a glass break-seal and a small trap to facilitate removal of dissolved gas. Prior to irradiation the hydrocarbon sample was thoroughly degassed by the conventional freeze-pump technique and the cycle repeated four times. Cyclohexane was used as a chemical dosimeter. The hydrogen yield, G(H2) = 5.3, determined by Schuler and Allen16 was used to calculate the amount of energy absorbed in each glass cell. A shallow 2-inch diameter aluminum dish was used for the study of liquid roduct formation. This geometry permitted a thin layer oFliquid to be irradiated approximately uniApproxiformly a t a dose rate of 8.0 X 10% e.v./g./min. (9) (a) L. H. Gevantman and R. R. Williams, Jr., ibid., 56, 569 (1952); (b) E. N. Weber, P. F. Forsyth and R. H. Schuler, Radiation Research, 8, 68 (1955); (c) A. Prevost-Bernas, A. Chapiro, C . Cousin, Y . Landler and M. Magat, Disc. Faraday Soc., 12, 98 (1952); (d) W. Wild, ibid., 12, 127 (1964). (10) Radical yield is defined as the total number of free radicals produced per 100 e.v. energy absorbed. (11) The author is indebted to R. W. Crowe and A. H. Sharbaugh for these hydrocarbon samples. (12) R . W. Crowe, J. K. Bragg and A. H. Sharbaugh, J . A p p l . Phys.. 26, 392 (1954). (13) ’E.E. Charlton and W. F. Westendorp, U E Reuiew, 44, 652 (1941). (14) R. R. Hente and M. Burton, J . Am. Chem. Soc., 7 3 , 532 (1951). (15) R. H.Schuler and A. 0. Allen, ibid., 77, 507 (1955).
Nov., 1957
RADIATION CHEMISTRY
mately 2 g. of liquid was weighed into the dish and a 1mil aluminum cover placed over the dish. The dish was then mounted on a thermostated metal block a fixed distance from the generator window. T o determine the effect of dissolved air, the aluminum dish was prepared for irradiation in a Nz dry box (continuous N: flow) using a liquid sample which had been previously degassed. The amount of energy absorbed by the li uid was determined with an ionization chamber of identica? geometry.lB The conversion factor 93 ergs/g./r. was used to calculate the energy absorption in the hydrocarbon li uids. 2.3 Gas Analysis.-A?ter irradiation the glass cell was sealed directly to a high vacuum analytical apparatus,17 which utilized a mercury cutoff to isolate the sample from the main analytical section. The sample was frozen in liquid nitrogen and the volatile as pumped into a calibrated Saunders-Taylor apparatus.'* $rhe degassing was repeated until all the gas was removed, usually two or three cycles were sufficient. The gas sample was collected in a bulb for mass spectrometric analysis. The irradiated sample was then degamed at the temperature of ethyl bromide mush (-119"). This gas fraction was removed in two steps, first i t was condensed into a liquid nitrogen tra which was then brought to the temperature of melting et{ yl bromide and the gas pumped into the calibrated volume. Quantitative removal of this fraction was considerably more difficult and required several degassing cycles. This fact combined with the relatively low yield of gas resulted in poor reproducibility. The gas sample was collected in a bulb for mass spectrometric analysis. 2.4 Liquid Analysis.-The amount of double bond formation was determined by infrared analysis using a PerkinElmer I . R. spectrometer (model no. 21). The infrared spectrum of the unirradiated liquid was determined with the same cells used for the irradiated liquid. The increase in absorbance at 10.36 p was used to determine the transvinylene double bonds; similarly the amount of vinyl double bonds was determined a t 11.00 p. The concentration of double bonds was calculated from the measured absorbance using the average molecular extinction coefficients given by McMuway and Thornton.'@ These authors found that the individual extinction coefficients did not vary by more than 20% from the average value. Separate experiments in this Laboratory with trans-hexene-2 and trans-octene-4 gave molecular extinction coefficients in agreement with the values of McMurray and Thornton. The reproducibility of the measured absorbances for different samples of irradiated hydrocarbon was about 5%. Number average molecular weights for the hexadecane samples were determined cryoscopically in cyclohexane with a precision of 10%. Gas-liquid partition chromatography was used to determine the nature of the liquid products in more detail.20 A Perkin-Elmer vapor fractometer (model 154) was used. For most purposes a single column, either one or two meters long, designated column A by the manufacturer, was used in this study. The column consisted of l/Anch stainless steel tube packed with Celite impregnated with didecyl phthalate as the stationary liquid phase. The sample, between 10 to 50 microliters, was carried through the column in a stream of high purity helium gas maintained at constant pressure (22 p.s.1.g.). The maximum recommended column temperature was 150°, thus substances with boiling points up to about 230" could be detected in a reasonable time. For qualitative analysis, the constituents of an irradiated sample could be identified by measurement of retention times (constant carrier gas flow rate) provided that calibration samples were available. Confirmatory identification of some of the constituents was accomplished by mass spectrometric analysis of the fractions which were removed in a liquid nitrogen trap. For the liquid nitrogen trapping experiments it was advantageous to lead the sample from the thermostated chamber through a short length of heated stainless steel tube directly to the liquid nitrogen trap. The ( 1 6 ) E. J. Lawton and J. S. Balwit, private communication.
(17) (1955). (18) (1941). (19) (20)
H. A. Dewhurst and M. Burton, J . Am. Chem. SOC.,17, 5781 K. W. Saunders and H. A. Taylor, J . Chem. Phys., 9, 616
H. L. McMurray and V. Thornton, A n d . Chem., 84,318 (1952). The author is much indebted to E. H. Winslow for hia generous
assistance with these studios.
O F n-ALK.4NE
25
LIQUIDS
1467
-
-
X N
r
-
-low' 0 - 8 X 0
10 ENERGY
20
30
40
I 6 0
v)
4 Y 0 2 =
50
x Fig. 1.-Production of hydrogen and methane as a function of the energy absorbed in n-hexane liquid. ABSORBED, e v
helium gas in the trap was pumped away before the sample was expanded into the mass spectrometer .21 Control experiments with known amounts (1-3%) of n-pentane, n-heptane and n-octane in n-hexane showed that the trapping procedure was satisfactory. For quantitative analysis solutions of known concentration were prepared in a given hydrocarbon. The dimer and intermediate products were calibrated only with the straight chain hydrocarbon. Since these hydrocarbons have approximately the same thermal conductivity it was assumed that the calibration would be valid for the corresponding isomers. The calibration study showed that the area per cent. was not directly proportional to the mole per cent.
3.0. Results and Discussion Gas Products.-Hydrogen gas is a major product from the radiolysis of the saturated aliphatic hydrocarbons. Small amounts of methane and higher hydrocarbon gases also are formed. Figure 1 shows the production of hydrogen and methane as a function of the energy absorbed in n-hexane. The gradual decrease in hydrogen yield a t higher doses may be due partly to scavenger action of the olefin product and partly t o a back reaction with hydrogen. The CH4 production increases linearly with the energy absorbed up t o 3.5 X loz1e.v. Similar results were obtained for the series of n-alkanes from pentane to hexadecane. The hydrogen yields are considered reliable to 5% and the methane yields reliable to 20%. The amounts of Cz and Cs hydrocarbons formed did not exceed 20% of the total gaseous product. The hydrogen and methane yields for a number of n-alkane liquids are given in Table I. These results show that the hydrogen yield is independent of the length of the carbon atom chain whereas the methane yield decreases with increase in the length of the carbon atom chain. These results do not support the early measurements of Schoepfle and Fellows3 who found that the hydrogen yield decreased with increase in the length of the carbon atom chain. The results of Schoepfle and Fellows 3.1.
(21) The Euthor is indebted to F. J. Norton for the preliminary ma88 spectrometer identifications.
1468
H. A. DEWHURST
Vol. 61
recently have been re-calculated,22 and the Gvalues obtained are appreciably lower than those in Table I. This however may be largely a question of dosimetry. The hydrogen yields from hexane and heptane (Table I) are in good agreement with recent determinations.2*
independent of the ionization density. Although these results indicate that the hydrogen yield is not greatly affected either by the state of aggregation or the ionization density nevertheless the mechanism of hydrogen formation may not be the same. Henri and c o - ~ o r k e r sobserved ~~ a hydro= 3.5 for the a-particle radiolygen yield of G(H2) TABLEI sis of n-hexane vapor. This low value, about 30% YIELD OF HYDROGEN AND METHANE FROM RADIOLYSIS OF lower than the yield from the liquid, may be largely n - A h n m LIQUIDS due to the fact that 40% of the hexane had reacted. U (rnolecules/100 e.v.) The methane yield is also shown in Table 1 as a n-Alkane Ha CHI function of the number of carbon atoms. For the Pentane 4.2 0.4 liquid hydrocarbons the CH, yield gradually deHexane 5.0 .15 creases with increase in the chain length. The Heptane 4.7 .09 methane yield recently reported for liquid hexane by Octane 4.8 .08 Krenz,' G(CH4) = 0.41 is about twice the value Nonane 5.0 .07 obtained in the present work. The reason for this Decane 5.2 -06 discrepancy is not apparent. Miller, et U Z . , ~ found Dodecane 4.9 .05 that the methane yield comprised about 0.5 mole % Hexadecane 4.8 -04 of the volatile gases from n-octacosane, in agreeIt is of interest to compare the hydrogen yield ment with the results of Breger.6 The methane from the liquid alkanes with that from gaseous and yield from polymethylene was not measurable.* solid alkanes. The yield of hydrogen from the a- The combined results suggest that the methane particle radiolysis of gaseous alkanes' is about the arises principally from the chain ends as pointed out same as that for the liquids. Similarly, the hydro- by Burton.26 The gaseous hydrocarbons, ethane, for the solid propane and butane, all gave approximately the gen yield determined by Miller, et hydrocarbons (n-octacosane and polymethylene) same methane yie1d.l Henri and co-workersZ4 was approximately the same as that for the liquids. reported a methane yield of G(CH4) = 0.44 for the The combined results show, to a first approxima- a-particle radiolysis of n-hexane vapor. tion, that the hydrogen yield is independent of the 3.2. Liquid Products.-Several methods were state of aggregation, dose rate and ionization den- employed to identify the nature of the liquid sity. Schuler and Allen16have recently shown that products. Changes in functionality, e.g., unsaturathe hydrogen yield from cyclohexane liquid is also tion, were determined by infrared spectroscopy. Preliminary mass spectrometric examination of 4.0 irradiated hexane liquid showed the formation of hexene and higher molecular weight hydrocarbons. A more complete identification of the liquid prod35 ucts was obtained by combined gas-liquid partition chromatography and mass spectrometry. 3.2.1. Infrared Results.-Infrared analysis of 3.0 the irradiated hydrocarbons showed that only two kinds of double bonds were formed, namely, transvinylene and vinyl. Figure 2 shows the production 2.5 of trans-vinylene unsaturation as a function of the 0 total energy absorbed for hexane, dodecane and X hexadecane. The gradual decrease in the yield of E trans-double bonds with increase in the energy aby 2.0 sorbed can be attributed to the scavenger property W J of the olefinic product. For this reason, the initial 0 1 yields were determined from the initiaI slopes of I .5 the curves. This procedure can be justified by the fact that the hydrogen production is linear within the initial part of these curves. The production of 1.0 vinyl double bonds was a linear function of the energy absorbed and was approximately the same for all hydrocarbons studied. However, the method 0.5 for the vinyl analysis was not good enough to detect small changes. The yield of trans-vinylene unsaturation was de0 termined for the following n-alkanes; hexane, hep5 IO 15 20 25 ENERGY ABSORBED, ev/pm X tane, octane, nonane, dodecane and hexadecane. Fig. 2.-Formation of trans-vinylene unsaturation aa a It was found that the trans-vinylene yield increased function of the energy absorbed. with increasing chain and approached a limiting value of G(trans-vinylene) = 2.0. It is of consid(22) B. M. Tolbert and R. M. Lernmon, Radiation Rsaearch, 3, 52 (24) V. P. Hanri, C. R. Maxwell, W. C. White and D. C. Peterson, (1955). I
I
a
v)
I
( 2 3 ) P. F. Forsuth. E. N. Weber and R. H. Schuler, J . Chsm. Phys., 92,-66 (1954).
THIS JOURNAL, 66, 153 (1952). (25) M. Burton, izd., 61, 786 (1947).
L
Nov., 1957
RADIATION CHEMISTRY OF HE ALKANE LIQUIDS
erable interest that the limiting yield is approximately the same as the unsaturation yield observed for solid n-octacosane.8 The vinyl yield, although small, was found to be independent of chain length for the liquid hydrocarbons. The formation of vinyl double bonds was not observed in the solid phase.8 I n the gas phase there is relatively little quantitative work available about the production of unsaturation. Lind and Bardwelll found that unsaturated products appeared only in the liquid phase which settled out on the walls of the reaction vessel. Honig and Sheppard also obtained evidence for the presence of olefin product in the liquid products. Irradiation of the saturated aliphatic hydrocarbon liquids in the presence of air did not affect the yield of trans and vinyl double bonds. Furthermore, infrared spectra of samples irradiated in the presence of air did not show the formation of any oxygenated products. It has been shown26that this is due t o a twofold effect: (1) low oxygen concentration and (2) high dose rate used. A carbonyl concentration of approximately loT6 mole/g. would have been detected readily. 3.2.2. Molecular Weight Measurements.Hexadecane was used to determine the crosslinking efficiency by the method of molecular weight change. The reciprocals of the number average molecular weights are shown in Fig. 3 as a function of the energy absorbed. The slope of the line multiplied by Avogadro's number gives the change in the number of molecules per unit energy absorbed. From this number the yield for the production of crosslinks was calculated, G(crosslinks) = 1.8. This yield is appreciably lower than the value obtained for n-octacosane, G = 2.SZ7and probably can be attributed to the effect of state. CharlesbyBaobtained a higher value (G = 4) which was stated to be independent of the carbon chain length from polyethylene to heptane. I n a subsequent paper Charlesby~reported a value G(crosslink) = 3.1 which is in fair agreement with Miller's value. For the low molecular weight hydrocarbons (Ci t o (3%) Charlesby used large radiation doses (500 to 2500 mr.) and therefore the values obtained are not representative of the original hydrocarbon molecule. The total gas yield, mainly hydrogen, from hexadecane cannot be accounted for completely by the sum of the unsaturation and crosslinking yields, G(crosssince G(H2) = 4.8, while G(C = C) links) = 3.8. Therefore additional Hz producing reactions are required and they can be found in the intermediate molecular weight product described below (see 3.2.3). Figure 5 shows that hexadecane irradiated a t liquid nitrogen temperature and then immediately warmed to room temperature showed no measurable change in the molecular weight. This behavior is in agreement with the results from gas-liquid partition chromatography of n-hexane irradiated at liquid nitrogen temperature.26 The chromatograms showed that the dimer yield was greatly decreased at liq. Nz temperature.
+
(26) H. A. Dewhurst, unpublished resulte.
(27) Miller's U-value has been recalculated on baais of 93 ergs/g./r.
1469
4.6-
3L 14
I +
ENERGY IO ABSORBED, ey./gm x IO-*'
5
Fig. 3.-Reciprocal number average molecular weight as a function of energy absorbed in n-hexadecane; 0,room temperature irradiation; 0, liquid nitrogen temperature irradiation.
i P 0 Y J
0
1
8
1
0 -RETENTION 6 0
S J\ , , , , ,
TINE (NIMS) I5 IO
.....................
6
0
'i
>,,A 4
w
b
Y ) 1 6 0 4 6 r K ) 3 6 X ) O 2 O I 5 C- RETEMTION TINE (NlNSL
IO
6
0
Fig. 4.-Chromatograms of n-hexane: A and B, 2-meter column, T = 50'. A = control; B, = irradiated; C = irradiated, Cmeter column; T = 35". Energy absorbed, 8.7 X loa1 e.v./g.
3.2.3. Gas-liquid Partition Chromatography.The technique of gas-liquid partition chromatography has been shown to be a powerful tool for the analysis of a wide variety of volatile organic compounds on the semi-microscale.2s This method has been found to be invaluable for the separation and identification of the products from irradiated hydrocarbon liquids.29 Because of the temperature limitation of the apparatus, studies were confined to the lower members of the n-alkane series, namely, pentane, hexane, heptane and octane. Chromatograms of the hydrocarbon liquids were always ob(28) (a) A. T. James and A. J. P. Martin, J. A d . Chdm., 6, 105 (1956); (b) N. H. Ray, ibid., 4, 21 (1954). (29) H. A. Dewhurst, J . Chsm. Phys., 24, 1254 (1956).
H. A. DEWHURST
1470 A
Vol. 61 Product
(CHI) gas analysis CI C, C4
-
n HEXANE
G
rnoleculeaj100 e.v
(0,20) 0.22
CS Nexene-2
.10 .24 .10 .20
than the ethane yield reported by Krenz, G(CaH6) = 0.69. Similar results were obtained with pentane, hep0 AIR c tane and octane. In all cases it was found that the L W lower members of the alkane series were formed. -! LL Gas chromatograms, obtained a t 150", of irradi30 25 20 15 IO RETENTION TIME (MINS). ated n-hexane liquid, Fig. 5B, show the formation of a large number of products (at least 12) which are eluted from the column after n-hexane and presumably are higher boiling materials. The peaks designated Cs, C9, Clo and Clz were found to have retention times characteristic of the corresponding n-alkane. The formation of a small amount of CI1 product was found in subsequent experiments. The peak Cs was further identified by mass spectrometry of the separated fraction and found to consist only of n-octane. With a column temperature of either 100 or 50' cf. Fig. 4B, a peak was found which had the same retention time as n-heptane. The peak was preceded by two peaks which have been as25 20 15 IO 5 0 signed as heptane isomers. At 150" the heptane -RETENTION TIME (MINS). peaks were not resolved from the large amount of nFig. 5.-Chromatograms of n-hexane, 2-meter column, The peaks designated Cat,CQt,Clotand Clzt T = 150': A = control; B = irradiated. Energy ab- hexane. have been assigned tentatively as isomeric products sorbed, 8.7 X loa1e.v./g. of the corresponding straight chain hydrocarbon. The peak designated Cs' was separated in a liquid tained over a temperature range in order to deter- nitrogen trap and found by mass spectrometry to mine the complete spectrum of products. consist of a mixture of isomeric octanes. Complete Typical chromatograms of n-hexane before and identification of this fraction was not accomplished. after irradiation are shown in Figs. 4 and 5. Figure Further evidence support of the assignment of 4B shows that several low boiling products are the C' products asinisomers was obtained from reformed which are not sufficiently resolved for identi- tention time studies which showed that the isomers fication. Improved resolution of these products have lower retention times than the corresponding was accomplished, as shown in Fig. 4C, by lowering straight chain. More complete resolution of the the column temperature to 35' and increasing the isomer groups probably can be accomplished length of the column to 4 meters. The product with a suitable stationary liquid phase in the colpeaks shown in Fig. 4C were found, by their reten- umn. Chromatograms obtained at 150" were cartion times, to correspond to CZ,Ca, Cq and CS hy- ried out beyond the region where Cla and CMhydrodrocarbons. The fraction corresponding to each carbons could be expected. There was no evidence peak was separated in a liquid nitrogen trap and of products in this region. From the measurement shown by mass spectrometry to consist of a normal of relative peak areas the following yields were calalkane and the corresponding olefin. Therefore the peak in Fig. 4C designated CZrepresent a mixture culated. G of ethane and ethylene, and similarly for the other Produot moleculesjioo e.v. peaks. It was generally found that the didecyl C? C,' (0.15) phthalate column did not separate the paraffin and Cs Cs' 0.41 corresponding olefin. However, with a 4-meter colcs CS' ,92 umn hexene-2 was separated from the large excess cia f CJO' .43 of n-hexane as shown in Fig. 4C. Hexene-1, if presc 1 2 42' 2.0 ent, would not be resolved from the hexane. The amount of material represented by each peak was A major fraction of the C7 to CUproduct was found determined by measurement of the relative peak to be branched chain hydrocarbons. These results areas with a planimeter. In this way the follow- together with the data for C1, CZ, Cs, Cq and CS ing yields were calculated. product formation show that appreciable C-C bond To minimize systematic errors due to evaporation scission occurs. The ratio G(C-H)/G(C-C) = 2, of these volatile constituents the samples were where G(C-H) and G(C-C) represent the yield for stored in Dry Ice immediately after irradiation. C-H and C-C bond scission, respectively, calcuNevertheless the Cz, Ca and C4 yields are probably lated from the experimental product distribution is low. The yield of Cz hydrocarbon is much lower smaller than the ratio expected for a random rup2
I
C-
+ + + +
1471
RADIATION CHEMISTRY OF %-ALKANE LIQUIDS
Nov. 1957
8 0
5w
-
n OCTANE
e
X64
