THE UNIVERSITY OF MICHIGAN INDUSTRY PROGRAM OF THE COLLEGE OF ENGINEERING THE CHLORINATION OF M-XYLENE AND METHYL NAPHTHALENES IN THE PRESENCE OF GAMMA RADIATION W. Mo Sergy J. Jo Martin L. Co Anderson March, 1958 IP-277

ACKNOWLEDGMENT The authors wish to express their appreciation for the generous financial assistance of the United States Atomic Energy Commission which supported a project for this study in the Fission Products Laboratory of the Engineering Research Institute of the University of Michigan. The authors wish also to acknowledge the efforts of the following persons who aided with the experimental work: Jun Oishi, Wan Y. Chon, Gerald H. Golden, and Ernest W. Breland, Jr. ii

TABLE OF CONTENTS Page ACKNOWLEDGMENT.................... oooo.ooo o....... o........ ii INTRODUCTION.................... o.................... 1 EXPERIMENTAL PROCEDURE............................4....... RESULTS AND DISCUSSION................................... 5 I. REACTION OF M-XYLENE......o.......... o..,............ 5 A. Details of the Reaction..,,,.,,o.... o o....,o.. 5 B. Kinetic Data., oo,,o...o........... o,...o..... 6 C. Product Analyses.....o.............. o..o.....o. 9 D. Radiation Yields., o.ac o,,,. o.,,,.. o..... o 12 E. Discussion.........o o o o.,...,oo.............. 12 II. REACTION OF 1-METHYL NAPHTHALENE..o...o..oo........o..... 13 A. Details of the Reaction........,..,.......,.... 13 B. Kinetic Data....oo,...................o......... 14 C. Product Analyses............... o o............ 17 D. Radiation Yields...............o..........o.. 17 E. Discussion.,o o o o o......o o o o o o. o..o......... 19 IIIo REAClTION OF 2-METHYL NAPHTHALENE.......o................. 20 A. Details of the Reaction...oo.o...........o...... 20 Bo Kinetic Data...........o.. o.. o.....oo............ 21 C. Product Analyses O... o.o oooo oo..o............. 24 D. Radiation Yields..,.....oo.oo,..ooooooo.oo..o 24 Eo Discussion.. O... o......o..o.....oo.,o 26 SUMMARY..oo...o........o...................................... 27 BIBLIOGRAPHY...................... o... a a a a a 30 iii

INTRODUCTION

r The University of Michigan * Engineering Research Institute I 1 INTRODUCTI ON In 1951 the University of Michigan initiated a broad program to discover uses for the radioactive fission products which are obtained in large amounts from the operation of nuclear reactorso Several groups in this laboratory have directed their efforts toward finding chemical reactions that are promoted by radiationo One of the principal forms of radiation given off by the fission products is gamma radiationo As no fission products were readily available cobalt-60 sources of gamma radiation were employed in all studies, The selection of chemical reactions for thorough study was governed by either or both of the following general objects ives: (a) To study reactions of commercial or possible commercial importance which are promoted by radiation; (b) To study reactions of a general kind which might aid in explaining the mechanism of radiation effectso The chlorination of aromatic hydrocarbons was one of the chemical reactions which was investigated extensively. This paper presents the final experimental work on the chlorination studies conducted in this laboratoryo The effect of gamma radiation on the reaction of chlorine with benzene and toluene was reported from this laboratory by Harmer (1,2)o Recently, further work was reported on the chlorination of mesitylene, naphthalene, and ethyl benzene (394) The current data on m-xylene, 1-methyl naphthalene, and 2-methyl naphthalene are presented to extend and complete the series of aromatic compounds which have been chlorinated in the presence i I 2

The University of Mi~chigan I - - Engineering Research Institute of gamma raaiationo In this study. kinetic dat: 9 product ana!yses, and radiation yields for the ch.-orinatic n oi these:rree aromatic compounds are presented at on: emoerat, a:cd one radiation dose rateo The radiation yields are expressed in terms of "'G" values (molecules reacted per 100 electron volts of radiation energy absorbed)o The product analyses are not exhaustive and are designed to indicate generally wvhat type of reaction products were obtainedo Investigations of the reaction of chlorine with xylene have generally involved the use of a pure isomer as a starting material, If a mixture of isomers was used9 identification of the reaction products was somewhat more difficult0 Direct chlorination of xylene may result in (a) substitution on the side chaln, (b) substitution on the ring9 or (c) addition to the ring: These reactions were found to occur singly or in combinationo Chlorination of all three pure isomers of xylene and commercial xylene mixtures have been reported in the literatureo Photochemical methods, both in the liquid and vapor phases, have resulted in chlorination of the side chains (5$6.798'!luclear substitution reactions have been affected b, the use of' catalysts such as ferric chloride and iron (910l11,12,15;,l14). The reaction of chlorine with xylene by addition has been reported under special conditions (6915), The addition of chlorine to m-xylene occurred during low-temperature chlorinationo Upon warming the addition product, HC1 was given off and substituted m-xylenes were formed with two chlorine atoms in the aromatic 3

..The University of Michigan T Engineering Research Institute nucleus (15) The reaction of chlorine with a xylene mixture has been reported to proceed both by substitution and by addition in the presence of gamma radiation (-, 17). No significant data on'-the photochemical chlorination of naphthalene or its methyl derivatives have been reported A kinetic study of the chlorination of naphthalene in the presence of gamma radiation has been reported earlier from this laboratory (3)~ In this earlier study literature references for previous work on the chlorination of naphthalene have been presentedo EXPERIMENTAL PROCEDURE A complete description of the procedure and equipment used in the chlorination studies has been presented in a previous report (3)o A short summary of the general method is given below0 The rates of chlorination of m-xylene, 1-methyl naphthalene, and 2-methyl naphthalene were calculated by an overall chlorine material balance on the reacting system. The inlet chlorine gas flow rate was measured with a calibrated flow metero Samples of the exit gases from the reactor were taken periodically throughout the experimento The amount of unreacted chlorine gas and the amount of chloride ion in each exit gas sample were determined by chemical methodso The radiation used in all the experiments was supplied by an 1,800 curie cobalt-60 gamma sourceo The radiation dose rate was determined by ferrous sulfate dosimetry (16). The reaction mixtures from each run were distilled in 4

The University of Michigan Engineering Research Institute a simple vacuum distillation unit. Chemical methods were used to determine the total chlorine content of each distillate fraction. RESULTS AND DISCUSSION The results obtained from the chlorination of m-xylene9 1-methyl naphthalene, and 2-methyl naphthalene are presented in three separate sectionso A summary of the experimental conditions used in the three reactions is shown in Table Io In all the runs9 the chlorine inlet rate showed a slight variation among the sampleso However, during the taking of any given sample, the chlorine inlet rate was constant t TABLE I, Summary of experimental conditions used in the chlorination of m-xylene, lmethyl naphthalene, and 2-methyl naphthalene at -5~Co Run No 1 2 3 4 5 6 Compound Reacted m-xyl ene m-xylene 1-methyl naphthalene 1-methyl naphthalene 2-me thyl naphthalene 2-methyl naphthalene Dose Rate Sample Krep/hr Time ___.__ min o none 3 60o3 3 none 3 60o3 3 none 3 60o3 3 Run Time mino 69 68 59 59 60 60 Chlorine Inlet Rate mMmin 21o6-21o7 21o4-21o6 14o8-14o9 15o0-15ol 15 o0-15 o 15o0-15ol m Io Reaction of m-xylene Ao Details of the reaction For each run the reactor was charged with 60 ml (Oo49 mol I I J 5 -

The University of Michigan * Engineering Research Institute of dried and distilled m-xyleneo The m-xylene used was.Last-ian Kodak white label grade number 2750 The reactor temperature was brought to -b'C befor~" ti | run was startedo When chlorine was first admitted to the reactor a 3-4 degree rise in temperature occurredo Some 4-5 minutes later the temperature suddenly rose 27 degrees more At this point a vigorous flow of exit gases from the reactor was noted and the odor of HC1 was detectedo The temperature of the reactor was brought back to the control setting in 6-7 minutes by the recorder-controller A sharp temperature drop of 6-8 degrees occurred about 29-31 minutes after the run was started. It will be seen later that this temperature drop corresponded with a sharp decrease in the rate of substitution0 Thus this temperature effect suggested that the substitution reaction could be exothermic in nature Bo Kinetic data The kinetic data obtained for the reaction of chlorine with m-xylene by substitution are shown in Figure lo Smooth reaction rate curves were obtained for -both the irradiated and non irradiated runso A very high reaction rate was observed for the substitution reactiono Within the limits of experimental error, no effect of radiation on the substitution reaction vas demonstratedo Figure 2 shows the rate of chlorine addition to m-xylene These data Illustrated that radiation had essentially no effect 6

20 18 z UJ CL CM u E: LU z 0 C LU a9 16 14 12 10 8 6 4 0 RUN i (NON IRRADIATED) ____| ____ l____ ____ * RUN 2 (IRRADIATED)_ - * 0 ll l l I \Illll _ _ __ __1_ __ _ _ 2 0 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 TIME (MIN.) FIGURE 1. RATE OF CHLORINE SUBSTITUTION ON META-XYLENE AT -5~ C.

20 18 16 14 LU 23 12 E: 10 a~ 8 z 0 C9 4 2 -2 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 TIME (MIN.) FIGURE 2. RATE OF CHLORINE ADDITION TO META-XYLENE AT -5~ C.

The University of Michigan T Engineering Research Institute on the addition reactiono Both reaction rate curves showed a large and abrupt rise in the middle of the reactiono This rise in the addition reaction rate coincided with a marked decrease in the rate of substitution. Again9 as in earlier studies (3,4), there was an indication that the substitution reaction occurred preferentiallyo Each curve of Figures 1 and 2 was graphically integrated to obtain the amount of chlorine reacted in ten minute intervals throughout the runo These values appear in Table IIo Examination of these data showed that9 both for the substitution and addition reactions9 the total amount of chlorine reacted without radiation increased by less than 5 percent when radiation was employedo Total chloride analyses on the reaction mixtures gave values of 42o6 percent for run 1 and 42o4 percent for run 2o These values showed that the extent of reaction was identical for both runso Co Product analyses The results obtained from product analyses on the m-xylene reaction mixtures are shown in Table IIIo The ranges in the theoretical percent chloride are due to the possible formation of either substitution or addition productso The fractions obtained from the distillation of the reaction mixtures were colorless liquidso In the second fractions the liquids turned to transparent semi-solidso In the third fractions the colorless liquids became cloudy and the fourth 9

I ~ ~ ~~ ~ __ i l TABLE II. Amounts of chlorine reacted by substitution and by addition in successive time intervals during the chlorination of m-xylene at -50~C. Type of Run Dose Rate Reactiorl Number Krep/hro I Millimoles of Chlorine Time Intervals, minutes 0-10 10-20 20-30 30-40 40-50 50-60 Total IF r Substitution Substitution Addition Addition 1 none 2 1 2 60.3 none 60.3 172o0 172,0 156.8 164o0 16400 160.9 42.5 46. 0 57o3 55o0 76.5 21o2 7.5 33.2 13.4 584. 5 612,0 A - 4 *, C: 3' er D) 0 m 3 m_ 3 cn:r m_ 59.3 154.0 146.0 48.5 140.o3 145.2 72.5 47o5 49.0 I~~~~~~~-~~~.I

TABLE IIIo Analytical data obtained from the distillation of chlorinated m-xylene reaction mixturese =1 u,..m C Type of Theoretical Chloro Percent Derivative Chloride& Exp e rime nt al Percent Chloride 25 2 Run Fraction Number Number Boiling Po Pressure mme Hgo 0~2 Ool int Fraction Temp. Volume ~C mlo Mono 2502 1 2 I I 25 25 2604 24o0 25 o3 Os o* 3 Di 40o1-40 o6 42 ol 1 2 II IT 003 0o1 67-78 42-65 903 6o7 40 o2 H Tri Tetra Penta 50,4-50o9 57o7-58o7 62o8-63.7 55.5.. 55o 5 54 4 60o2 64 o5 1 2 1 1 III III IV 0o2 003 0o2 0o2 78-91 65-100 95-97 99-110 305 5o5 7o1 V m 3 _. ro OQ _ I' - 0 Sf m v, f) In n 61 o4 2 IV 004 100-110 703 Hexa 67,2-68.1 The range in values is due to the possible formation of either substitution or addition products.

The University of Michigan * Engineering Research Institute fractions showed the formation of a white solid material. No unreacted m-xylene was isolatedo In both runs the most abundant fraction was related to the mono-chloro derivative of m-xyleneo The formation of a di-chloro derivative was also indicated, No evidence for the presence of the tri- or tetrachloro derivatives was foundo The fractions in Table III related to these derivatives were thought to be mixtureSo The last fractions from both runs indicated the formation of a pentachloro derivativeo From these analytical data it can be seen that no significant difference in product formation exists between the irradiated and non irradiated runso Do Radiation yields The kinetic data of Figures 1 and 2 and the related data in Table II show that gamma radiation had no effect on the rate of chlorination of m-xyleneo Thus, G values of zero were obtained both for the substitution and addition reactionso A discussion of several factors pertinent to the calculation and interpretation of G values has been presented in an earlier report (3)0 Eo Discussion Earlier work on the chlorination of a commercial xylene mixture in the presence of gamma radiation (16 17) yielded results not in agreement with the current datao The reasons for this lack of agreement in data are similar to those presented for the chlorination of naphthalene (3) i 12

The University of Michigan - T Engineering Research Institute Of the three xylene isomers the meta isomer is known to be the most reactiveo This fact is reflected in the current data which show a very high rate of reaction for the chlorination of m-xyleneo The results for m-xylene compare favorably with those previously obtained for mesitylene (3)o The maximum substitution rate for m-xylene is lower than that obtained for mesityleneo However, the maximum addition rate for m-xylene is much higher than that obtained for mesityleneo On the basis of structure, the results obtained from the chlorination of these two compounds appear to be consistento IIo Reaction of 1-methyl naphthalene Ao Details of the reaction A 13 percent by weight solution of 1-methyl naphthalene in carbon tetrachloride was used in each of the experimental runso The reactor was charged with 12o3 gm (Oo086 mole) of l-methyl naphthalene and 80 gm of carbon tetrachlorideo A commercially available grade of l-methyl naphthalene was used (Eastman Kodak P2415)o Although it was originally dark amber in color, the l-methyl naphthalene was a clear opalescent liquid after distillationo The chlorine input flow rate used was very similar to that used for the chlorination of naphthalene (3)~ When the temperature of the system was at -50C, chlorine was admitted to the reactor at this flow rate to saturate the reaction mixture0 During this period the exit gases were passed through a solution 13

The University of Michigan * Engineering Research Institute containing silver nitrate0 After 5-6 minutes a precipitate of silver chloride app;are'' and the odor of HC1 was detected0 The runs were started -within t'i n:.-.:; minute since the precipitate indicated the start of t.le reaction, In both runs the temilerature rose 14-15 degrees when chlorine was first introduce.:Lnto.t. ractor. [:, f.il.'i;u.lt to -( -t-ro the tempercat..Cre 1for t1;",.' ~i_ f':.' s ol.'T'h reafte: the control was good0 B0 Kinetic data The rates of reaction which were calculated for the chlorination of l-methyl naphthalene are shown in Figures 3 and 4o Data obtained from the graphical integration of these curves are listed in Table IVo The kinetic data presented for the substitution reaction in Figure 3 show that gamma radiation prolonged the initial reaction rate, As a result, it can be seen from Table IV that the total amount of chlorine reacted by substitution in 60 minutes in the irradiated run is about 23 percent greater than that in the non irradiated run0 A maximum reaction rate plateau was observed for the substitution reaction0 From Figure 4 it is seen that the rate of chlorine addition to 1-methyl naphthalene was not affected to any extent by gamma radiation, In Table IV the total amounts of chlorine reacted by addition in 60 minutes differ by less than 2 percento The curves for the addition reaction in Figure 4 are somewhat different from those previously encountered in this laboratory0 The present data showed. a reaction rate plateau in the initial 14

z uJ CM -U ui I-, Z O LJ u6 3 2 1 0 0 5 10 15 20 25 30 35 40 45 50 55 60 65 FIGURE 3. TIME (MIN.) RATE OF CHLORINE SUBSTITUTION ON 1-METHYL NAPHTHALENE AT -5~ C. z u LU CY N: LU IO LUJ 14 12 10 8 6 4 2 0 -2 0 5 10 15 20 25 30 35 40 45 50 55 60 65 TIME (MIN.) FIGURE 4. RATE OF CHLORINE ADDITION TO 1-METHYL NAPHTHALENE AT -5~ C. 15

TABLE IV Amounts of chlorine reacted by substitution and by addition in successive time intervals during the chlorination of 1-methyl naphthalene at -50C Type of Reaction Run Dose Rate Number Krep/hr:eR C: 3.Z, -< o Total =1 CFO Millimoles of Chlorine Time Intervals, minutes 0-10 10-20 20-30 30-40 40-50 50-60 -- ---------— ~~~~~~~~~~~~,-4i-. -— 1 - - -- -.. -.. r+lraolllllDlePILI~r ~ - I -~-~ I.- ~C- C-~ L~- — P~W~s*-91- —CI-U~ u~~M~l~er MCIC;YYY~~IF~-l*L~hWW~iC-~- T:ll~-;.~rir%-ur~a-ucc~C~ .- e~:ilrrir~.~i:-i IX cl~:F U Substitution 0) Substitution Addition Addition 3 4 3 4 none 60 3 none 60 3 i 2509 26,0 2203 25 8 13 3 7 8 500 2305 12 9 41l 121,0 120.05 11P4 o 8 73 5 11o5 64o0 24 5 3o0 000 3~3 125o0 124o0 106o0 77 6 95 3 m a.r -3 4-A40 5 m 446 o6 uo -I 0 c>:y' eC

The University of Michigan T Engineering Research Institute part of the reaction~ Previous data from other reactions showed this plateau usually occurred in the latter part of the reactiono The effect of radiation on the extent of chlorination of 1-methyl naphthalene was indicated by total chloride analyses performed on the reaction mixtureso The values obtained were 51ol percent for the non irradiated run and 50o4 percent for the irradiated runo Thus, it appeared that radiation had no effect on the overall reactiono However9 a specific and favorable effect of gamma radiation on the substitution reaction was shown by the kinetic datao Co Product analyses The original reaction mixtures were dark brown in coloro Only two fractions were obtained from each run after distillationo All the distillate fractions were bright yellow in color and showed the formation of a solid material on standing~ Total chloride analyses were performed on these fractions and the results are listed in Table Vo The results shown in Table V allowed no definite conclusionso However, the formation of both a tri- and tetrachloro derivative of 1-methyl naphthalene was indicated0 Do Radiation yields Radiation vyields for the reaction of chlorine with 1-methyl naphthalene have been expressed in terms of G values based on chlorineo The data of Table V was used for the calculationso For the substitution reaction, a G value of 25,100 was 17

TABLE V Analytical data obtained from the distillation of chlorinated 1-methyl naphthalene reaction mixtureso _ __ -~- -r, ------ -----— 111 — as-u ~ —-— ul -r~-~a-uuurauuuuJ.. Type of Chl o ro Derivative Theoretical Percent Chloride* Experimental Percent Chloride Run Fraction Nmbr umb e r Numb er Boiling Point Pressure Temp, mmo Hgo ~C Fract ion Volume ml Cm 3 _. O _. I 3 -e 0 7 Mono 20 1 Di 33o3 - 33o6 Tri 43o0 - 43 3 39o4 44o2 3 4 3 I I II 004 30-147 0 o3 125-154 0o3 147-151 H 00 Tetra 5o5 5o5 50.0 - 50 7 47ol 49.5 4 II 0o4 154-156 305 The range in values is due to the possible formation of either substitution or addition products m Go 3 _. 3 11 ro ro _" 3 0 ro m m fA. 1 Vu r+ P+ c f

The University of Michigan T Engineering Research Institute calculated using a 60-minute reaction timeo A G value of zero was obtained for the addition reactiono It has been recent practice to calculate G values for consecutive time intervals throughout the reaction (3,4)o This approach is best adapted to a reaction which shows a reasonably high radiation yieldo In the case of 1-methyl naphthalene the relatively small radiation effect is best expressed by an average G value for a specified reaction timeo Eo Discussion In naphthalene the primary substitution reaction occurs in the alpha-position which is activated by the adjacent aromatic ringo Reactions subject to steric hindrance result in substitution in the beta-position0 For substitution on 1-methyl naphthalene, the 4-position is the preferential point of attack being under the directive influence of the methyl group and the adjacent aromatic ringo In the chlorination of 1-methyl naphthalene a low rate of substitution was observed experimentally0 Actually a methyl group is available for substitution as well as the 4-positiono Yet, compared to naphthalene (3) only a relatively small increase in rate was observed for the substitution reactiono A reaction rate plateau was evident for the substitution reactiono This plateau has been characteristic of chlorination reactions in which the reactant contains an alkyl side chaino Some observations on the general shape of the addition 19

The University of Michigan * Engineering Research Institute curves obtained for 1-methyl naphthalene have already been madeo The rate and extent of chlorine addition to 1-methyl naphthalene were found to be virtually unaffected by the presence of radiationo However, the addition of chlorine to naphthalene was reported to be greatly affected by gamma radiation (3) It appears that the presence of a methyl group in the 1-position of the naphthalene molecule causes a drastic decrease in the radiation yield for additiono In contrast to the decrease in radiation yield, the overall addition reaction rate for 1-methyl naphthalene was actually higher than that for naphthaleneo It is worthwhile to mention that a similar effect of the methyl group on radiation yield was demonstrated for the benzene and toluene addition reactions (192)o In the current experiments the observed reaction rates were initially almost equal to the chlorine input rate0 Thus9 it is possible that higher rates of reaction may be obtained if a higher chlorine input rate were usedo IIIo Reaction of 2-methyl naphthalene Ao Details of the reaction A 13 percent by weight solution of 2-methyl naphthalene in carbon tetrachloride was used in each experimental runo The sample of 2-methyl naphthalene used was Eastman Kodak white label grade number 2416o The reactor charge and general procedure were the same as that described for 1-methyl naphthaleneo In both runs the temperature rose 12-14 degrees when chlorine was introduced into the reactor and precipitation of 20

lir- - II 4C r. m I Ef lh 1 MOm & lw Dd% o d% -, % % IW% % 04, m - - Ine university o Ivilcnigan * cngineering IKesercn IInsLIUte silver chloride was observed some 7-9 minutes latero Each run was started 10 minutes after chlorine was first admitted to the reactor Bo Kinetic data The kinetic data obtained for the chlorination of 2-methyl naphthalene are shown in Figures 5 and 60 The areas under these curves were graphically integrated and these data appear in Table VIo A very low rate of substitution was observed for 2~ methyl naphthaleneo Figure 5 again demonstrated a plateau for the reaction rate curveso Examination of these curves showed that radiation had little effect on the substitution reaction rateo In Table VI the total amounts of chlorine reacted by substitution were found to differ by less than 6 percento The curves for the addition reaction in Figure 6 show that radiation had a significant effect on the reaction rateo From Table VI it can be seen that the total amount of chlorine reacted in 60 minutes for the irradiated run is about 34 percent greater than that for the non irradiated runo As in the case of l-methyl naphthalene, a reaction rate plateau was observed during the initial part of the addition reactiono In Figure 6, the scatter of the last four data points of run 5 about the zero axis has been shown to be characteristic for a zero addition reaction rate (4)o The kinetic data for the addition reaction appear to be in agreement with the total chloride anals es performed on the 21

z., w E IM z 0 kJ iu I,,, 0 5 10 15 20 25 30 35 40 45 50 55 60 65 TIME (MIN.) FIGURE 5. RATE OF CHLORINE SUBSTITUTION ON 2-METHYL NAPHTHALENE AT -5~ C. z LU Cd CM u E uJ ICZ z u U Le 14 12 10 8 6 4 2 0 I I I I I a RUN 5 (NON IRRADIATED) |~ - -~am, -- -- - A RUN 6 (IRRADIATED) A\~ A _. I., I I I - - — I I I I. I I -- I I -2 0 5 10 15 20 25 30 35 40 45 50 55 60 65 TIME (MIN.) FIGURE 6. RATE OF CHLORINE ADDITION TO 2-METHYL NAPHTHALENE AT -5~ C. 22

TABLE VI Amounts of chlorine reacted by substitution and by addition in successive time intervals during the chlorination of 2-methyl naphthalene at -5~Co Millimoles of Chlorine Type of Reaction Run Number Dose Rate Krep/hr Time Intervals, minutes 0-10 10-20 20-30 30-40 40-50 50-60 Substitution Substitution CA Addition I Addition 5 none 6 5 6 60o3 none 60 3 17o0 12o0 130o0 137 0 15o6 12 o0 123o6 9 o5 4o0 lo0 0o0 Total 0' i:~' s.{,*;t,* "7:LS i%:' %'.': o. ti,', " -U.L,'.'T:':=1.r':',:'.".s " 47o1 n' Sr 44.6 3 357 o3 11 o6 6o5 89o5 14 42 15 0oO 24 5 1.0 000 136.0 113.0 5800 10.4 478.9 m 3 rm 3 m cn r_ Io

The University of Michigan * Engineering Research Institute reaction mixtureso These analyses indicated more product formation in the irradiated run than in the non irradiated runo The values were obtained for the total chloride content were 490O percent for run 5 and 53~4 percent for run 60 C. Product analyses The original reaction mixtures were dark tan in color, Only two distillate fractions were obtained from each runo The first fractions consisted of pale yellow liquids0 The second fractions were similar in appearance but on standing these fractions became turbid as solid material started to form. The results of total chloride analyses performed on these fractions are given in Table VIIo The product fractions obtained were similar in nature to those obtained for 1-methyl naphthaleneo The analytical data indicated the possible formation of both tri- and tetra-chloro derivatives of 2-methyl naphthaleneo It is of interest to note that fractions related to the tri-chloro derivative were not obtained in the irradiated runo Do Radiation yields Radiation yields for the chlorination of 2-methyl naphthalene have been calculated from the data presented in Table VIo A G value of zero was obtained for the substitution reaction For the addition reaction a G value of 173,000 was obtained using a 60 minute reaction time 24

TABLE VII Analytical data obtained from the distillation of chlorinated 2-methyl naphthalene reaction mixtureso _ ____ ~ ~ _~__,~ ~~~llilkl-~LY~~nriUV-~*~~illU~n*~~~l.~Lnn ~* -n~ ~Nn*Z~~rra p a ra - - Type of Chloro Derivative Theoretical Percent Chloride Experimental Percent Chloride Run Fraction Numb e r Number Boiling Point Pressure mrilo Hgo Temp o oc Fracti on Volurrme ml o -< =r m C: _*. 3 r+ 0 - * =1 - *,, a) 3F' Mono 20 ol Di 3353 - 33o6 Tri 43o0 - 4303 5000 ~ 5007 4358 I II Tetra 51 o8 5 0.1. 0~2 0o7 105 1.35 r o6 131-135 31 51 o I II 1 321 52 150 6.F. Penta 56 4 = 55o7 rm m mc The range in values is due to the possible formation of either substitution or addition productso

The University of Michigan * Engineering Research Institute Eo Discussion The reaction of chlorine with 1-methyl naphthalene has already been compared with that of naphthaleneo This comparison can now be extended to include 2-methyl naphthaleneo It might be expected that the reactions of the two methyl substituted naphthalenes would be very similaro For example, there are the same number of positions available for substitution on both compoundso Also it is reasonable to assume that the reactivity of these positions will not differ to any great extent between the two compoundso However, the experimental results obtained for 2-methyl naphthalene are quite different from those obtained for 1-methyl naphthaleneo The most significant difference in reaction between 1-methyl naphthalene and 2-methyl naphthalene is in the radiation yieldso In the chlorination of 2-methyl naphthalene, gamma radiation had a large effect on the addition reaction and very little effect on the substitution reactiono In the case of 1methyl naphthalene this effect was reversed as only the substitution reaction was affected by radiationo Recent work on the chlorination of ethyl benzene has shown that impurities present in the reactant can cause unusual effects and can inhibit the reaction almost comple tely (4)o Aside from considerations of reactant purity, the shift of the methyl group on naphthalene from the 1-position to the 2-position resulted in significant differences in the chlorination reaction0 A resolution of these differences in reaction can only be accomplished by a thorough 26

I [ The University of Michrigan Engineering Research Institute I J study of the two reactionso The general shapes of the reaction rate curves obtained for 1-methyl naphthalene and 2-methyl naphthalene were quite similaro Both the substitution and addition curves showed reaction rate plateaus during the early part of the reactiono For the substitution reaction3 the rate of reaction of 2-methyl naphthalene was much lower than that of 1-methyl naphthalene, The overall substitution reaction, however9 proceeded at a very low rate of reaction for both compoundso It was also evident that the addition reaction took place at a high reaction rateo The maximum addition reaction rate was found to be slightly greater for 2-methyl naphthalene than that for 1-methyl naphthaleneo For the addition reaction the average G value obtained for 2-methyl naphthalene was much smaller than that previouslyobtained for naphthaleneo Thus, the comparison of the chlorination reactions of i-methlyl naphthalene and naphthalene viti-t those of toluene and benzene already made can be extended to include 2-methyl naphthalene SUMMARY lo The rates of chlorination of m-xylene, 1-methyl naphthalene, and 2-methyl naphthalene have been determined under irradiated and non irradiated conditions at -5~Co 2o For all three compounds studied. kinetic data showed that reaction with chlorine occurred both by substitution and by additiono 27

T " % II &'a%,, ft -,&'s % ".-%4 A'^ Lw;-v % I " a Am Be M r h I; 1 _.++:4I..~. I ne uivrcl-Ily uir viiliiilidi * 1 LInriimCI 111r Irarcan rIIIbLILULrC 3o Radiation yields expressed as G values eased on chlorine have been calculated for b'e three reactions st u.ieCd, 4o At -5~C garara radiation was found to have no effcct on'he rate of chlorination of m-xyleneo Analytical data showed essentially no differences in product formation between the irradiated and non irradiated reactionso As a result, G values of zero were obtained for both the substitution and addition reactions 5o Although structurally very similar, 1-methyl naphthalene and 2-methyl naphthalene exhibited different types of behavior in the presence of gamma radiationo At -5~C. both chlorination reactions were found to be favorably affected by radiationo Apart from the differences in radiation effects, the reaction rate curves and analytical data obtained for both compounds were quite similaro 6o Kinetic data showed that' during the chlorination of 1-methyl naphthalene, only the substitution reaction was affected by the presence of gamma radiationo For the substitution reaction an average G value (based on chlorine) of 25100 was obtained for a reaction time of 60 minutes A G value of zero was obtained for the addition reactiono 7o During the chlorination of 2-methyl naphthalene. kinetic data showed that only the addition reaction was affected by the presence of gamma radiation~ For the addition reaction an average G value (based on chlorine) of 173O000 was obtained for a reaction time of 60 minuteso A G value of zero was obtained for the substitution reaction0 28

The University of Michigan Engineering Research Institute So Analyses of the m-xylene reaction mixtures showeC th>) mono-chloro derivative to be the most abundant product of reactiono The formation of the di- and penta-chloro derivatives was also indicated~ 9o The results obtained from the chlorination product analyses of 1-methyl naphthalene and 2-methyl naphthalene were verysimilar in nature0 The formation of a tri- and tetra-chloro derivative was indicated for both compounds, 10o For the chlorination reaction, the introduction of one methyl group into the naphthalene molecule gave a radiation effect similar to that found for berzene and tolueneo In both aromatic systems the introduction of a methyl group resulted in a large decrease in the overall radiation yieldo 29

BIBLIOGRAPHY -30

The University of Michigan * Engineering Research Institute BIBLIOGRAPHY 1o Harmer, Do Eo, Lo Co Anderson and Jo Jo MIartin9 Chemo iEngo Progo Sympo Series, Volo 50, No 119 253-57 (1954) 2o Harmer, Do Ei, Jo JO Martin and Lo Co Anderson, Chemo Engo Progo Sympo Series, Volo 52, No. 19, 53-59 (1956)o 3o Sergy,'W Mo, Jo Fo Hanus, JO Oishi, Jo J.o MTartin and Lo Co Anderson, The Chlorination of Mesitylene and Naphthalene in the Presence of Gamma Radiation, Eng':esos Insto9 Univo of Micho, Ann Arbor, Michigan, May, 1957o (Submitted to the A Co So for publication) 4o Sergy, Wo Mo, Jo Oishi, J J Martin and L Co Anderson, The Effect of Gamma Radiation on the Reaction of Chlorine with Ethyl Benzene, Engo Res. Insto, Univo of iicho,9 Ann Arbor, Michigan, July, 1957o (To be submitted for ouolication) 5o McBee, Eo To, Ho 3B Hass, P. E0o feimer, G. Mo Rothrock, Wo EBo Burt, R0o Mo Robb and A0 Ro Van Dyken, Indo Engp Chemo 39, 298-301 (1947)o 6 McBee, Eo To, H. Bo Hass, et alo, Natlo Nuclear Energy Ser,, Divo VII 1, 207-21 (1951)o 7o Harvey, PO Go, F0 Smith, PMo Stacey and Jo Co Tatlow, Jo AoplO Chemo (London) 4, 319 (1954)o 80 Asolkar, Go Vo and PO Co Guha, Jo Indian Chemo Soco 23, 47-52 (1946)o 9o Kruger, Ao, Bero 18, 1755 (1885)o 10o Jacobson, O., Bero 18, 1760 (1885)o 1 Wahl, Mo Ho, Anno Chimo (11), 5, 5-82 (1936)o 12o Willgerodt, Co and Ro Wolfien, Jo Pr. Chemo 39, 402-12 (1889) 13o Boyars, Co, Jo Amo Chemo Soco 75, 1889-90 (1953)o 14o Harvey, Po Go, F0 Smith, Mo Stacey and Jo Co Tatlow, Jo Applo Chemo (London) 4, 325 (1954) 15o Kharasch, MI So and M0 Go Berkman, JO Orgo Chem. 6, 810-17 (1941)o 31

The University of Michigan * Engineering Research Institute 16o Anderson9 L0 Co,.Bo Go Bray and Jo Jo Martin, Proceedings of the International Conference on the Peaceful Uses of Atomic Energy9 Geneva9 Switzerland9 Aug0 8-209 1955, Volo 159 235419 United Nations 1956o 17o Martin, Jo J0o L C0 Anderson, eto alo, Progress Report 1943:44-60-P Engo Reso Insto, The University of Michigan9 Ann Arbor, Michigan March9 19560 180 Weiss, Jo, Nucleonics 10, 28 (1952)o 32