- Email: [email protected]
Study of reactions of benzoyl peroxide with amines
3116
M. F. MARGARITOV~_and K. A. RUSAKOVA
8. S. V. VINOGRADOVA, V. V. KORSHAK and S. N. SALAZKIN, Izv. Akad. N a u k SSSR, Seriya khim. 308, 1966 9. A. P. RUDAKOV, F. S. FLORINSKII, M. I. BESSONOV, K. N. VLASOVA, M. M. KOTON, and P. M. TANUNINA, Plast. massy, No. 9, 26, 1967 10. C. E. SROOG, A. L. ENDREY, S. V. ABRAMO, C. E. BERR, W. M. EDWARDS and K. L. O L M E R , J. Polymer Sci. A3: 1373, 1965 11. V. V. KORSHAK, S. V. VINOGRADOVA, Yd. S. VYGODSKII, S. A. PAVLOVA and L. V. BOIKO, Izv. Akad. l~auk SSSR, Seriya khim., 2267, 1967 12. P. W. MORGAN, J. Polymer Sci. A2: 437, 1964 13. N. A. ADROVA, M. I. BESSONOV, L. A. LAIUS and L. P. RUDAKOV, P o l i i m i d y - - n o v y i klass termo-stoikikh polimerov (Polyimides, a New Class of Heat-resistant Polymer). Izd. " N a u k a " , 1968 14. G. L. SLONIMSKII and A. A. ASKADSKII, Mekhanika polimerov, No. 1, 36, 1965 15. A. A. ASKADSKII, Vysokomol. soyed. A9: 418, 1967 (Translated in Polymer Sei. U.S.S.R. 9: 2, 471, 1967) 16. S. N. ZHURKOV and S. A. ABASOV, Vysokomol. soyed. 3: 441, 1961 (Not translated in Polymer Sci. U.S.S.R.) 17. G. SCHWARZENBACH and M. BRANDENBERGER, Helv. Chim. A c t a 20: 1253, 1937 18. A. ETIENNE and J. C. ARCOS, Bull. ehim. France, 727, 1951 19. Yd. S. VYGODSKII, Dissertation, 1967 20. British P a t e n t 467824, 1935; Chem. Abstr., 31, 8944, 1937 21. W. UTERMARK and W. SCHICKE, Schmelzpunkttabellen organischer Verbindungen. Acad. Verlag Berlin, 1963 22. G. RABILLOUD, B. SILLION and G. De GAUDEMARIS, Makromol. Chemie 108: 18, 1967 23. V. V. KORSHAK, S. V. VINOGRADOVA, Yd. S. VYGODSKII and B. N. YUDIN, Izv. Akad. N a u k SSSR, Scriya khim., 1405, 1968
STUDY OF REACTIONS OF BENZOYL PEROXIDE WITH AMINES * l~I. F . M_~ROXRITOVA a n d K . A. RUSXKOVX M. V. Lomonosov I n s t i t u t e of Fine Chemical Technology, Moscow
(Received I1 December 1968) THE study of peroxide reactions with amines, and also of polymerization in the presence of such systems was dealt with b y Gambaryan, Chaltykyan, Bagdasaryan, H o m e r , Imoto, Grabak, a n d others. These systems were found to be fairly effective in hydrocarbon media a t low temperatures. The m a j o r i t y of investigators thought the reaction of peroxides with amines to give rise to a molecular electron donor-acceptor complex, which produced free radicals during decomposition and initiated the polymerization. * Vysokomol. soyed. A l l : No. 12, 2741-2746, 1969.
3117
Reactions of benzoyl peroxide with amines
Thus, H o m e r [1] suggested t h a t the benzoyl peroxide (BP)-aromatic amine reaction takes place with transfer of a single electron from the undivided pair on the nitrogen of BP. The resulting complex then decomposed and produced a cation-radical of the amine, a benzoate ion a n d a benzoate radical. The main reaction product was benzoic acid. Direct confirmation of the principal BP-dimethylanfline (DMA) reaction was given in another report [2] b y infrared and electron absorption spectroscopy of DMA radical formation and of benzoic acid production.
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Fxo. 1. B P decompositi'on in the presence of DMA emulsions at 20°C. a: [BP] =0.0745 mole/1, org. phase, [DMA] (as mole/1, org. phase): 1-0.15, 2-0"0745, 3--0.037, 4--0"018. b: [DMA] =0-0745 mole/l, org. phase, [BP] (as mole/l, org. phase): 1--0.018, 2--0.037, 3 - 0.0745, 4-0-149. The kinetic s t u d y of the P B reaction with DMA and with aniline (AN) was made b y several investigators [3-6]. The reaction of B P with triethylamine (TEA) had been studied earlier only in methyl methacry]ate and styrene solutions [7]. This report describes the results of studying the B P - D M A reaction in emulsions with benzene, t h a t of B P with T E A and with A N in solutions and emulsions.
EXPERIMENTAL S t a r t i n g materials. The B P was purified b y precipitation from its chloroform solution with methanol, followed b y vacuum.drying. The DM_~_and T E A were purified b y the m e t h o d described elsewhere [7, 8]. The A N was twice distilled in a nitrogen stream and i n vacuo. Cryoscopie benzene was used. We also employed spectroscopy in addition to the method given [7] to determine the peroxide concentration (iodometric). F o r this purpose we determined the spectral line intensity of the carbonyl groups in benzene solutions (infrared spectral line at 1749 em -1) A s t a n d a r d curve, in which the optical density of the 1794 em -x line was plotte.d against concentration of BP, was used in the calculations [9]. The emulsifier was an aliphatic sodium sulphonate with average composition CxsHsxSO,Na, and cetylpyridinium chloride (2 ~ w/w on the aqueous phase). Preliminary tests h a d shown the emulsifier not to affect the rate of B P decomposition. A 2 : 1 ratio of aqueous to organic phase was used in all tests (v/v).
RESULTS The reaction was carried out by keeping the concentration of one component constant while varying that of the other, and also at different temperatures (in t h e r a n g e 5 - 4 0 ° C ) . T h e o r d e r o f t h e r e a c t i o n w i t h r e s p e c t t o t h e i n d i v i d u a l
3118
M.F. MAI~GXRITOVAand K. A. RUSAXOVA
c o m p o n e n t s o f the system (from the initial rates) a n d the a c t i v a t i o n energies, either in solution or emulsions, were determined. T h e results of these e x p e r i m e n t s are
1"2
0"8
I
18"0 37"2 7#.5 [BP] op [DMA], mole/l.. 10s
FIG. 2. Initial rate of the BP-DMA reaction in an emulsion as a function of concentration of one of the components: 1--[DMA] =const., 2-[BP] =const. reproduced in Figs. 1 a n d 2 (for system B P - D M A ) a n d Figs. 3 a n d 4 (for s y s t e m B P - T E A ) , while Figs. 5 a n d 6 give t h e m for B P - N A ; t h e y are also t a b u l a t e d . REACTIONS OF
System
BP
AND HYDROPEROXIDE ~rITH AMINES
Reaction order relative to BP
E~
kcal/mole
Ionization potential, eV
[amine In benzene solution
BP-DMA BP-TEA BP-AN CHP -DMA TBHP-DMA
1~.~ E3] 7.14 [10]; 7-3 [11] 7-5 [12] 11.35 7.7 [10, 12]; 7.95 [11] 13.8 15.4 I I 17-7
1 1
In water-benzene emulsion BP-DMA BP-TEA BP-AN
1
1 -
1
1
10-8 11.3 14.4
Note: CHP-cumyl hydroperoxide, TBHP--tert.butyl hydroperoxide.
The a b o v e Table, a n d Figs. 2, 4, 7 show t h a t all t h e studied systems give a first-order reaction relative to each c o m p o n e n t , i.e. t h e reaction is bimolecular. F u r t h e r p r o o f o f this are the results contained in the work b y Gol'shtein et al. [13], which showed the reaction o f t e r t i a r y amine with acid a n h y d r i d e s t o yield a 1 : 1 complex. T h e rate e q u a t i o n for the reaction o f B P with amines can therefore be w r i t t e n as: w-----k [BP] [amine].
Reactions of benzoyl peroxide with amines
3119
Attention is drawn to the fact t h a t the activation energy for B P with t e r t i a r y amines (DMA, TEA) in benzene solution, or in a benzene emulsion, is the same. The activation energy of the B P decomposition in the presence of a primary amine (aniline) is also practically the same in a benzene solution and in emulsions; it equalled 13.8 and 15 kcal/mole respectively. 70
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Fro. 3. BP decomposition in the presence of TEA solutions in benzene (spectral) at 31°C. a: [BP] =0.0745 mole/l., [TEA] =mole/].: 1--0.018, 2--0.037, 3--0.56, 4--0-0745, 5--0.149. b: [TEA] =0.0745 mole]]., [BP], mole]].: 1--0.0372, 2--0.0745, 3--0-10. LO ,w0
5o
r
I
~.5
Fo
log concentration
Fro. 4. Determination of the order of BP decomposition in the presence of TEA. 1--[BP] =0.0745 mole/]., [TEA] =variable, 2--[TEA] = 0.0745 mole/]., [BP] =variable. A point worth noting is t h a t the rate of the B P - D M A reactioh is the same as t h a t o f B P - T E A . This applied to solutions (Fig. 8) as well as emulsions (Fig. 9). The B P - A N reaction has a much lower rate.
3120
M . F . MARGARITOVAand K. A. RUSAXOVA
~. 20
50
E .~
3 fO 0
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200
30
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120
FIG. 5. B P decomposition in the presence of A N solutions in benzene a t 25°C. a: [BP] =0.037 mole/l, [AN] =mole/L: 1--0.111, 2-0.074, 3--0.037, 4 : 0 . 0 1 . b: [AN] =0-074 mole/1, [BP], mole/L: 1--0.222, 2--0.149, 3--0.074, 4--0-037.
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FIG. 6. B P decomposition in the presence of AN emulsions in benzene at 25°C. a: [BP] =0.037 mole/1.,org, phase,[/kN], mole/1.: 1--0.148, 2--0.074, 3--0"037, 4--0.020, 5-0.010. b: [AN]=0-74 mole/1, org. phase, [BP], mole/L: 1--0.148, 2--0.074, 3--0.037.
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b
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148 37 Concenfpotion "/03, mole/l.
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158
Fzct. 7. Determination of the reaction order of B P decomposition in the presence of a - benzene solutions, b -- emulsions, of AN. 1 -- 0.074 mole/l. AN, [BP] =variable, 2-- 0.037 mole/1. BP, [AN] =variable.
Reactions of benzoyl peroxide with amines'
312l
The comparison of the data obtained in our s t u d y of the ionization potentials of the amines led to the conclusion that the latter is the factor determining whether the reaction will take place. There is little difference of this factor between DMA and T E A and t h e y cause the same rate of B P decomposition; the activation energy is also the same. Where AN is present, which has a larger ionization potential t h a n the tertiary amines (about 8 eV), the B P decomposes more slowly. The activation energy of this process is larger b y 3-4 kcal/mol. 50
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60
Time, min FIG. 8
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Fio. 8. BP decomposition in benzene solutions contain ing different ~m~nes. [BP] = [~mine 0.0745 mole/1. 1--BP-DMA ( × ), BP-TEA (O), 3, 4-- BP-AN, 1, 3--35°C, 2,4--25°C. Fro. 9. B1) decomposition in the present of different amine emulsions at 20°C. [BP]= [amine] =0.0745 mole/1, org. phase. 1--BP-DMA, 2--BP-TEA, 3--BP-AN. The influence of the ionization potential on the reaction rate is also confirmed b y the fact that pyridine, with its ionization potential of 9.8 (9.3) eV, and quinoline or isoquinoline, do not react with B P [1], while tetramethyl-p-phenylenediamine, having an ionization potential of 6.5 eV, is known to react even at 0°C with BP. The equal reaction rates of DMA and TEA with BP, and also the equal activation energies for tertiary aromatic and aliphatic amines, are definite evidence of the alkalinity of the amine not affecting the reaction kinetics. Special attention should be given to the reactions of amines with hydroperoxides which decompose at temperatures above 100°C. We examined here the decomposition of cumyl hydroperoxide (CHP) and that of tert.butyl hydroperoxide (TBHP) in the presence of DMA. It became clear from our study of this reaction that the amine somewhat reduced the hydroperoxide decomposition temperature. The activation energy of this reaction, given in the Table, was much lower than that of thermal decomposition. This indicates that the amine particip a t e d in the reaction with the hydroperoxide.
3122
M. F. MAROARITOVAand K. A. RtTSAKOVA CONCLUSIONS
(1) T h e kinetics of t h e r e a c t i o n of b e n z o y l peroxide w i t h dimethylaniline, t r i e t h y l a m i n e , or aniline in solutions or emulsions of benzene were studied. T h e order of t h e reaction relative to each c o m p o n e n t was a l w a y s 1; this was irrespective o f w h e t h e r it t o o k place in solution or in a n emulsion. (2) T h e a c t i v a t i o n energies o f these reactions were calculated, a n d t h e conditions were f o u n d n o t to affect t h e m (in solution or emulsions). (3) T h e ionization p o t e n t i a l of t h e a m i n e was f o u n d to be t h e f a c t o r deciding t h e r e a c t i o n rate. T h e a l k a l i n i t y of the a m i n e h a d no effect on t h e kinetics of t h e process. (4) A r e a c t i o n was f o u n d to t a k e place b e t w e e n h y d r o p e r o x i d e s a n d amines. Translated by K. A. ALLEN
REFERENCES
1. L. HORNER, J. Polymer Sci. 18: 438, 1955 2. S. D. STAVROVA, G. V. PEREGUDOV and M. F. MARGARITOVA, Dokl. Akad. Nauk SSSR 157: 636, 1964 3. F. GRABAK, Dissertation, 1955 4. M. IMOTO and S. SHOE, J. Polymer Sci. 15: 485, 1955 5. K. F. O'DRISCOLL and E. N. RICHEZZA, J. Polymer Sei. 46: 211, 1960 6. R. I. MILYUTINSKAYA and Kh. S. BAGDASAR'YAN, Zh. fiz. khim. 34: 405, 1960 7. I. Yu. MUSABEKOVA and M. F. MARGARITOVA, Vysokomol. soyed. 3: 530, 1961 (Translated in Polymer Sci. U.S.S.R. 3: 4, 552, 1962) 8. L. FIESER and M. FIESER, Organic Chemistry (Russian translation), p. 531, Izd. inostr, lit., 1949 9. K. A. RUSAKOVA and M. F. MARGARITOVA, Vysokomol. soyed. B9: 515, 1967 (Not translated in Polymer Sci. U.S.S.R.) 10. F. I. VILESOV and A. N. TERENIN, Dold. Akad. Nauk SSSR 115: 744, 1957 11. G. BRIEGLEB and J. CZEKALLA, Z. Elektrochem. 63: 6, 1959 12. Sovremennye problemy fizicheskoi khimii (Modern Problems of Organic Physical Chemistry). p. 25, Izd. "Mir", 1967 13. S. B. GOL'SHTEIN, S. D. STAVROVA et aL, Dokl. Akad. Nauk SSSR 181: 134, 1968
M. F. MARGARITOV~_and K. A. RUSAKOVA
8. S. V. VINOGRADOVA, V. V. KORSHAK and S. N. SALAZKIN, Izv. Akad. N a u k SSSR, Seriya khim. 308, 1966 9. A. P. RUDAKOV, F. S. FLORINSKII, M. I. BESSONOV, K. N. VLASOVA, M. M. KOTON, and P. M. TANUNINA, Plast. massy, No. 9, 26, 1967 10. C. E. SROOG, A. L. ENDREY, S. V. ABRAMO, C. E. BERR, W. M. EDWARDS and K. L. O L M E R , J. Polymer Sci. A3: 1373, 1965 11. V. V. KORSHAK, S. V. VINOGRADOVA, Yd. S. VYGODSKII, S. A. PAVLOVA and L. V. BOIKO, Izv. Akad. l~auk SSSR, Seriya khim., 2267, 1967 12. P. W. MORGAN, J. Polymer Sci. A2: 437, 1964 13. N. A. ADROVA, M. I. BESSONOV, L. A. LAIUS and L. P. RUDAKOV, P o l i i m i d y - - n o v y i klass termo-stoikikh polimerov (Polyimides, a New Class of Heat-resistant Polymer). Izd. " N a u k a " , 1968 14. G. L. SLONIMSKII and A. A. ASKADSKII, Mekhanika polimerov, No. 1, 36, 1965 15. A. A. ASKADSKII, Vysokomol. soyed. A9: 418, 1967 (Translated in Polymer Sei. U.S.S.R. 9: 2, 471, 1967) 16. S. N. ZHURKOV and S. A. ABASOV, Vysokomol. soyed. 3: 441, 1961 (Not translated in Polymer Sci. U.S.S.R.) 17. G. SCHWARZENBACH and M. BRANDENBERGER, Helv. Chim. A c t a 20: 1253, 1937 18. A. ETIENNE and J. C. ARCOS, Bull. ehim. France, 727, 1951 19. Yd. S. VYGODSKII, Dissertation, 1967 20. British P a t e n t 467824, 1935; Chem. Abstr., 31, 8944, 1937 21. W. UTERMARK and W. SCHICKE, Schmelzpunkttabellen organischer Verbindungen. Acad. Verlag Berlin, 1963 22. G. RABILLOUD, B. SILLION and G. De GAUDEMARIS, Makromol. Chemie 108: 18, 1967 23. V. V. KORSHAK, S. V. VINOGRADOVA, Yd. S. VYGODSKII and B. N. YUDIN, Izv. Akad. N a u k SSSR, Scriya khim., 1405, 1968
STUDY OF REACTIONS OF BENZOYL PEROXIDE WITH AMINES * l~I. F . M_~ROXRITOVA a n d K . A. RUSXKOVX M. V. Lomonosov I n s t i t u t e of Fine Chemical Technology, Moscow
(Received I1 December 1968) THE study of peroxide reactions with amines, and also of polymerization in the presence of such systems was dealt with b y Gambaryan, Chaltykyan, Bagdasaryan, H o m e r , Imoto, Grabak, a n d others. These systems were found to be fairly effective in hydrocarbon media a t low temperatures. The m a j o r i t y of investigators thought the reaction of peroxides with amines to give rise to a molecular electron donor-acceptor complex, which produced free radicals during decomposition and initiated the polymerization. * Vysokomol. soyed. A l l : No. 12, 2741-2746, 1969.
3117
Reactions of benzoyl peroxide with amines
Thus, H o m e r [1] suggested t h a t the benzoyl peroxide (BP)-aromatic amine reaction takes place with transfer of a single electron from the undivided pair on the nitrogen of BP. The resulting complex then decomposed and produced a cation-radical of the amine, a benzoate ion a n d a benzoate radical. The main reaction product was benzoic acid. Direct confirmation of the principal BP-dimethylanfline (DMA) reaction was given in another report [2] b y infrared and electron absorption spectroscopy of DMA radical formation and of benzoic acid production.
"~
~ 80
/-
50
~
0
~
x/x ~
I
60
~
I
120 Time., min
-~
~
,
/
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~
I80
0
.
80
,
120 Time, m[n
.
,
180
Fxo. 1. B P decompositi'on in the presence of DMA emulsions at 20°C. a: [BP] =0.0745 mole/1, org. phase, [DMA] (as mole/1, org. phase): 1-0.15, 2-0"0745, 3--0.037, 4--0"018. b: [DMA] =0-0745 mole/l, org. phase, [BP] (as mole/l, org. phase): 1--0.018, 2--0.037, 3 - 0.0745, 4-0-149. The kinetic s t u d y of the P B reaction with DMA and with aniline (AN) was made b y several investigators [3-6]. The reaction of B P with triethylamine (TEA) had been studied earlier only in methyl methacry]ate and styrene solutions [7]. This report describes the results of studying the B P - D M A reaction in emulsions with benzene, t h a t of B P with T E A and with A N in solutions and emulsions.
EXPERIMENTAL S t a r t i n g materials. The B P was purified b y precipitation from its chloroform solution with methanol, followed b y vacuum.drying. The DM_~_and T E A were purified b y the m e t h o d described elsewhere [7, 8]. The A N was twice distilled in a nitrogen stream and i n vacuo. Cryoscopie benzene was used. We also employed spectroscopy in addition to the method given [7] to determine the peroxide concentration (iodometric). F o r this purpose we determined the spectral line intensity of the carbonyl groups in benzene solutions (infrared spectral line at 1749 em -1) A s t a n d a r d curve, in which the optical density of the 1794 em -x line was plotte.d against concentration of BP, was used in the calculations [9]. The emulsifier was an aliphatic sodium sulphonate with average composition CxsHsxSO,Na, and cetylpyridinium chloride (2 ~ w/w on the aqueous phase). Preliminary tests h a d shown the emulsifier not to affect the rate of B P decomposition. A 2 : 1 ratio of aqueous to organic phase was used in all tests (v/v).
RESULTS The reaction was carried out by keeping the concentration of one component constant while varying that of the other, and also at different temperatures (in t h e r a n g e 5 - 4 0 ° C ) . T h e o r d e r o f t h e r e a c t i o n w i t h r e s p e c t t o t h e i n d i v i d u a l
3118
M.F. MAI~GXRITOVAand K. A. RUSAXOVA
c o m p o n e n t s o f the system (from the initial rates) a n d the a c t i v a t i o n energies, either in solution or emulsions, were determined. T h e results of these e x p e r i m e n t s are
1"2
0"8
I
18"0 37"2 7#.5 [BP] op [DMA], mole/l.. 10s
FIG. 2. Initial rate of the BP-DMA reaction in an emulsion as a function of concentration of one of the components: 1--[DMA] =const., 2-[BP] =const. reproduced in Figs. 1 a n d 2 (for system B P - D M A ) a n d Figs. 3 a n d 4 (for s y s t e m B P - T E A ) , while Figs. 5 a n d 6 give t h e m for B P - N A ; t h e y are also t a b u l a t e d . REACTIONS OF
System
BP
AND HYDROPEROXIDE ~rITH AMINES
Reaction order relative to BP
E~
kcal/mole
Ionization potential, eV
[amine In benzene solution
BP-DMA BP-TEA BP-AN CHP -DMA TBHP-DMA
1~.~ E3] 7.14 [10]; 7-3 [11] 7-5 [12] 11.35 7.7 [10, 12]; 7.95 [11] 13.8 15.4 I I 17-7
1 1
In water-benzene emulsion BP-DMA BP-TEA BP-AN
1
1 -
1
1
10-8 11.3 14.4
Note: CHP-cumyl hydroperoxide, TBHP--tert.butyl hydroperoxide.
The a b o v e Table, a n d Figs. 2, 4, 7 show t h a t all t h e studied systems give a first-order reaction relative to each c o m p o n e n t , i.e. t h e reaction is bimolecular. F u r t h e r p r o o f o f this are the results contained in the work b y Gol'shtein et al. [13], which showed the reaction o f t e r t i a r y amine with acid a n h y d r i d e s t o yield a 1 : 1 complex. T h e rate e q u a t i o n for the reaction o f B P with amines can therefore be w r i t t e n as: w-----k [BP] [amine].
Reactions of benzoyl peroxide with amines
3119
Attention is drawn to the fact t h a t the activation energy for B P with t e r t i a r y amines (DMA, TEA) in benzene solution, or in a benzene emulsion, is the same. The activation energy of the B P decomposition in the presence of a primary amine (aniline) is also practically the same in a benzene solution and in emulsions; it equalled 13.8 and 15 kcal/mole respectively. 70
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]
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Fro. 3. BP decomposition in the presence of TEA solutions in benzene (spectral) at 31°C. a: [BP] =0.0745 mole/l., [TEA] =mole/].: 1--0.018, 2--0.037, 3--0.56, 4--0-0745, 5--0.149. b: [TEA] =0.0745 mole]]., [BP], mole]].: 1--0.0372, 2--0.0745, 3--0-10. LO ,w0
5o
r
I
~.5
Fo
log concentration
Fro. 4. Determination of the order of BP decomposition in the presence of TEA. 1--[BP] =0.0745 mole/]., [TEA] =variable, 2--[TEA] = 0.0745 mole/]., [BP] =variable. A point worth noting is t h a t the rate of the B P - D M A reactioh is the same as t h a t o f B P - T E A . This applied to solutions (Fig. 8) as well as emulsions (Fig. 9). The B P - A N reaction has a much lower rate.
3120
M . F . MARGARITOVAand K. A. RUSAXOVA
~. 20
50
E .~
3 fO 0
60
120 180 Time, rain
200
30
60 90 Tl'me , rain
120
FIG. 5. B P decomposition in the presence of A N solutions in benzene a t 25°C. a: [BP] =0.037 mole/l, [AN] =mole/L: 1--0.111, 2-0.074, 3--0.037, 4 : 0 . 0 1 . b: [AN] =0-074 mole/1, [BP], mole/L: 1--0.222, 2--0.149, 3--0.074, 4--0-037.
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20
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60
120 Time, rain
180
FIG. 6. B P decomposition in the presence of AN emulsions in benzene at 25°C. a: [BP] =0.037 mole/1.,org, phase,[/kN], mole/1.: 1--0.148, 2--0.074, 3--0"037, 4--0.020, 5-0.010. b: [AN]=0-74 mole/1, org. phase, [BP], mole/L: 1--0.148, 2--0.074, 3--0.037.
25
I
a
b
~
/
~o
Z
37
7#
III
8 5
148 37 Concenfpotion "/03, mole/l.
2
71/
111
158
Fzct. 7. Determination of the reaction order of B P decomposition in the presence of a - benzene solutions, b -- emulsions, of AN. 1 -- 0.074 mole/l. AN, [BP] =variable, 2-- 0.037 mole/1. BP, [AN] =variable.
Reactions of benzoyl peroxide with amines'
312l
The comparison of the data obtained in our s t u d y of the ionization potentials of the amines led to the conclusion that the latter is the factor determining whether the reaction will take place. There is little difference of this factor between DMA and T E A and t h e y cause the same rate of B P decomposition; the activation energy is also the same. Where AN is present, which has a larger ionization potential t h a n the tertiary amines (about 8 eV), the B P decomposes more slowly. The activation energy of this process is larger b y 3-4 kcal/mol. 50
× . I ~ ^~ Lx....
//'~2
~. zjO E
.30
"
0
30
60
Time, min FIG. 8
i
90
0
30
60 90 Time, rain
I2~?
Fie. 9
Fio. 8. BP decomposition in benzene solutions contain ing different ~m~nes. [BP] = [~mine 0.0745 mole/1. 1--BP-DMA ( × ), BP-TEA (O), 3, 4-- BP-AN, 1, 3--35°C, 2,4--25°C. Fro. 9. B1) decomposition in the present of different amine emulsions at 20°C. [BP]= [amine] =0.0745 mole/1, org. phase. 1--BP-DMA, 2--BP-TEA, 3--BP-AN. The influence of the ionization potential on the reaction rate is also confirmed b y the fact that pyridine, with its ionization potential of 9.8 (9.3) eV, and quinoline or isoquinoline, do not react with B P [1], while tetramethyl-p-phenylenediamine, having an ionization potential of 6.5 eV, is known to react even at 0°C with BP. The equal reaction rates of DMA and TEA with BP, and also the equal activation energies for tertiary aromatic and aliphatic amines, are definite evidence of the alkalinity of the amine not affecting the reaction kinetics. Special attention should be given to the reactions of amines with hydroperoxides which decompose at temperatures above 100°C. We examined here the decomposition of cumyl hydroperoxide (CHP) and that of tert.butyl hydroperoxide (TBHP) in the presence of DMA. It became clear from our study of this reaction that the amine somewhat reduced the hydroperoxide decomposition temperature. The activation energy of this reaction, given in the Table, was much lower than that of thermal decomposition. This indicates that the amine particip a t e d in the reaction with the hydroperoxide.
3122
M. F. MAROARITOVAand K. A. RtTSAKOVA CONCLUSIONS
(1) T h e kinetics of t h e r e a c t i o n of b e n z o y l peroxide w i t h dimethylaniline, t r i e t h y l a m i n e , or aniline in solutions or emulsions of benzene were studied. T h e order of t h e reaction relative to each c o m p o n e n t was a l w a y s 1; this was irrespective o f w h e t h e r it t o o k place in solution or in a n emulsion. (2) T h e a c t i v a t i o n energies o f these reactions were calculated, a n d t h e conditions were f o u n d n o t to affect t h e m (in solution or emulsions). (3) T h e ionization p o t e n t i a l of t h e a m i n e was f o u n d to be t h e f a c t o r deciding t h e r e a c t i o n rate. T h e a l k a l i n i t y of the a m i n e h a d no effect on t h e kinetics of t h e process. (4) A r e a c t i o n was f o u n d to t a k e place b e t w e e n h y d r o p e r o x i d e s a n d amines. Translated by K. A. ALLEN
REFERENCES
1. L. HORNER, J. Polymer Sci. 18: 438, 1955 2. S. D. STAVROVA, G. V. PEREGUDOV and M. F. MARGARITOVA, Dokl. Akad. Nauk SSSR 157: 636, 1964 3. F. GRABAK, Dissertation, 1955 4. M. IMOTO and S. SHOE, J. Polymer Sci. 15: 485, 1955 5. K. F. O'DRISCOLL and E. N. RICHEZZA, J. Polymer Sei. 46: 211, 1960 6. R. I. MILYUTINSKAYA and Kh. S. BAGDASAR'YAN, Zh. fiz. khim. 34: 405, 1960 7. I. Yu. MUSABEKOVA and M. F. MARGARITOVA, Vysokomol. soyed. 3: 530, 1961 (Translated in Polymer Sci. U.S.S.R. 3: 4, 552, 1962) 8. L. FIESER and M. FIESER, Organic Chemistry (Russian translation), p. 531, Izd. inostr, lit., 1949 9. K. A. RUSAKOVA and M. F. MARGARITOVA, Vysokomol. soyed. B9: 515, 1967 (Not translated in Polymer Sci. U.S.S.R.) 10. F. I. VILESOV and A. N. TERENIN, Dold. Akad. Nauk SSSR 115: 744, 1957 11. G. BRIEGLEB and J. CZEKALLA, Z. Elektrochem. 63: 6, 1959 12. Sovremennye problemy fizicheskoi khimii (Modern Problems of Organic Physical Chemistry). p. 25, Izd. "Mir", 1967 13. S. B. GOL'SHTEIN, S. D. STAVROVA et aL, Dokl. Akad. Nauk SSSR 181: 134, 1968