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Connection between the heterophase copolycondensation constants and the adsorption characteristics of monomers
The adsorption characteristics of monomers
2189
REFERENCES 1. K. MAYO and M. LEWIS, J. Am. Chem. Soc. 66: 1594, 1944 2. F. T. WALL, J. Am. Chem. Soc. 66: 2050, 1944 3. A. D. ABKIN and S. S. MEDVEDEV, Dokl. Akad. Nauk SSSR 56: 177, 1947
4. A. D. ABK1N and S. S. MEDVEDEV, Trudy 3 Konf, vysokomol, soyed., Izdat. Akad. Nauk SSSR, 1948
CONNECTION BETWEEN THE HETEROPHASE COPOLYCONDENSATION CONSTANTS AND THR ADSORPTION CHARACTERISTICS OF MONOMERS* L. B. SOKOLOV and L. V. TURETSKII Vladimirsk Synthetic Resin Research Institute (Received 5 January 1965)
THE copolymerization method widely used in the chemistry of high polymers can give important information about the mechanism of the reaction components by analysis of the copolymerization constants. The quantitative aspects of the copolycondensation method are not fully developed at present. Although a start was made [1] by publishing information on the calculation of the copolymerization constants for different variants of heterophase copolycondeusations [2-4], the values obtained were only used to draw qualitative conclusions regarding the characteristics of the mechanisms of the respective processes. By using very general theories about the mechanism of the processes occurring at the boundary surface, one can quantitatively assess the physical meaning of the copolycondensation constants of the heterophase variants of the processes (interfacial and gas-phase polycondensation). Where the reaction takes place only at the interface and is not complicated by reactions in space (of the phases), the composition of the copolymer will be determined by the concentrations of reagents A and B present in the reaction zone, i.e. at the interface. When surface-active monomers are used, the concentrations of A and B in the boundary layer will differ from those present in the solution and can be represented by the Boltzman equations [5]:
[A]'=[A] × e-E~/~r
(1)
[B]'--[B] × e -EBlaT
(2)
* Vysokomol. soyed. 7: :No. 11, 1997-2000, 1965.
2190
L.B.
SOKOLOV and L. V. TURETS~-I
where [A] and [B] are the concentrations in the space of the phases, [A]' and [B]' those present in the boundary layer, E a and E~ the changes of the energy potentials of molecules A and B during passage from the aqueous phase to t h e boundary surface, i.e. the reaction zone. One can show, by considering (1) and (2), that the equation for the copolymer composition suggested by [1] and given below as (6), does not change its general shape, except t h a t copolycondensation constant r in it should be understood to mean: r=roe_Cea - E#/m, (3) where r 0 is the true copolycondensation constant determining the ratio of the reaction rate constants of components A and B with a third component. Where A and B are members within a homologous series, equation (3) can be transformed into: r=roe_(~Em~ ~z~, (4) in which z/n is the difference in the n u m b e r of repetitive chain members in molecules A and B, and •E the change of the potential energy during the adsorption of one repetitive chain member. As the eAEmT of an aliphatic series of homologues is known [5] as the constant of the Traube rule, fl, one can write r = r o f l -zn ,
(5)
~n being the difference in the number of CH~-groups of homologues. We have shown [6] that the gas-phase polycondensation is less complicated, compared with intorfacial, by processes taking place in the space of the phases, so that one can verify the picture given above most satisfactorily by analysing the copolycondensation constants at the phase boundary between a liquid and a gas. The Table below lists the copolycondensation constants at the liquid-gas interface (gas-phase polycondensation). It gives the verified results of previous experiments [4] and new ones obtained afterwards. The conditions and results of the copolymcr syntheses were given earlier [4], the methods of polymer synthesis by gas-phase polycondensation in [6, 10]. The values of the polycondensation constants shown in the Table were calculated from equation: [A]/[A0] =([BJ/[B0])'
(6)
where [Ao] and [B0] are the concentrations of components A and B in the reaction mixture at the start, [A] and [B] are those at the end of the test, and r is the experimentally determined copolycondensation constant. The most interesting of the results shown in the Table are those involving systems containing aliphatic diamines, with the exception of ethylenediamine (systems 3-6 in the Table), as far as it concerns quantitative calculations. This
2191
The adsorption characteristics of monomers GAS-PHASE COPOLYCONDENSATION CONSTANTS OF SOME SYSTEMS
System Exp. No.
I) iamines Acid chloride Component A Ethylenediamine Ditto Hexa MD Hexa MD Hexa MD Tetra MD Ethylenediamine Hexa MI) p-Phenylenediamine
r
Component B Hexamethylenediamine I)itto Octa MI) I)eca MD I)eca MI) I)eca MD I)eca MI) Benzidine Benzidine
Copolycondensation constant
Oxalyl chloride Phosgene Oxalyl chloride Oxylal chloride Phosgene Oxalyl chloride Phosgene Oxalyl chloride Oxalyl chloride
0.60 0-57 0.45 0.21 0-20 0.11 0"07 0"23 0.84
MD - methylenediamine.
is because one can say that the reactivities of these diamines must be identical on the basis of their dissociation constants [.4]. Further-more, information is available about t h e Traube rule coefficient under different conditions within an aliphatic series of homologues [7, 8]. B y transforming equation (5) into a logarithmic equation to have it in a suitable form for processing the experimental results, and b y considering An, we obtain: In 1 / r = l n l/re+An × In fl (7) or, since r 0 equals one for systems 3 to 6, In 1/r:An × In ft.
(8)
I t follows from equations (7) and (8) that In 1/r is a linear function of An. The Figure shows the plot of In 1/r against An for copolymer systems in which aiiphatic diamines wore used. One can see good agreement between the above assumption and the experimental results. This confirms that In 1/r is a linear function of An in the series of aliphatic diamines. The above indicates that adsorption processes play an important part in the gas-phase polycondensation and that the reaction takes place mainly at the interface. I t also follows from equations (7) and (8) that the slope of the line in the figure gives Traube coefficient in an aliphatic series of homologues. Using this slope, the Traube coefficient was found to be 1.5, i.e. identical with that given in the literature. In should be noted that the literature does not contain any information about the Traube coefficient, as determined under our experimental conditions (bifunctional compounds, 90°C). It was also reported [7] that the T~aube coefficient
2192
L. B, SoxoLov and L. V. TURETSKII
approached unity on increasing the temperature; p~-2.7 [8] for bifunctional aliphatic compounds at 20°C. The diagram shows also a deviation from In 1/r being a function of An where systems of copolymers, in which ethylenediamine was used for the synthesis, were involved. This deviation can probably be explained by the different reactivity of ethylenediamine compared with other diamines within the series of homologues (see the values of the dissociation constants of the respective diamines in [4]), and also for other reasons.
oa
2
54
6
l 4
,
1
0
I
An
8
1/r as a function of ztn for copolymer systems obtained by using aliphatic diamines: a--systems with higher aliphatic diamines; b--systems with ethylenediamine. The numbers against the points are identical with those given in the Table.
We have thus a quantitative picture of the characteristics of the gas phase polycondensation of binary mixtures of diamines. It should be noted that the present case of the effect of adsorption of the reagents during this heterophase polycondensation was the simplest of all. It is very likely that the observed characteristics will also be found for other cases of heterophase polycondensation, especially those at the interface of two liquids. It is worth remembering that the above picture of the part played by adsorption during polycondensation at the interface is identical with that given by others [9] who studied the reaction with low molecular weight surfactants in boundary surface conditions. CONCLUSIONS
(1) A quantitative relation between the constants of copolycondensation and the adsorption characteristics of monomers in gas-phase reactions is given. (2) The experimentally found Traube coefficient for CH~-groups was identical with that given in the literature, which was obtained from surface tension measurements. Translated by K. A. ALLEN
Flow birefringenee of D N A molecules
2193
REFERENCES 1. L. B. SOKOLOV and T. L. KRUgLOVA, Vysokomol. soyed. 2: 704, 1960 2. V. V. KORSHAK, T. M. FRUNZE and L. V. KOZLOV, Izvest. Akad. N a u k SSSR, Otd. k_him. Nauk, 2062, 1962 3. V. V. KORSHAK, T. M. FRUNZE and L. V. KOZLOV, Izvest. Akad. N a u k SSSR, Otd. khim. Nauk, 2226, 1962 4. L. V. TURETSKII, L. B. SOKOLOV and V. Z. NIKONOV, Sb. Geterotsepnye vysokomolekularnye soyedineniya. (in: "Heterochain High Polymers".) Izdat. " N a u k a " 107, 1964 5. S. M. LIPATOV, Fiziko-khimiya kolloidov. (The Physical Chemistry of Colloids.) Gos. Khim. Izdat., 1948 6. L. B. SOKOLOV and L. V. TURETSKII, Vysokomol. soyed. 6: 346, 1964 7. P. REHBINDER, Z. phys. Chem. 111: 447, 1924 8. A. B. TAUBMAN, Dissertation, 285, 1948 9. A. A. ABRAMZOV, Yu. L. KIYANOVSKAYA and L. Ya.' KREMNEV, Zhur. priklad. Khim. 37: 2314, 1964 10. L. B. SOKOLOV, T. V. KUDIM and L. V. TURETSKH, Vysokomol. soyed. 3: 1370, 1961
FLOW BIREFRINGENCE AND FLEXIRILITY OF DESOXYRIBONUCLEIC ACID (DNA) MOLECULES* V. N . T S V E T K O V , L . N . A N D R E Y E V A a n d L . N . K V I T C H E N K O H i g h Polymer Institute, U.S.S.R. A c a d e m y of Sciences
(Received 10 March 1965)
OUR previous works [1, 2] reported the study of An and the directional angle of the flow birefringenee of DNA fragments obtained by ultrasonic disintegration. It showed that the difference between the main polarizations, 71--72, of DNA molecules increased with the molecular weight of the sample, M, in accordance with the optical propetries of the semi-rigid chains [3]. To obtain quantitative data on the flexibility of DNA molecules, we continued our dynamic flow birefringenee experiments and also extended these to a larger number of samples, and over a wider range of molecular weights. The DNA fragments were obtained by subjecting DNA solutions to ultrasonic and enzymic disintegration. SAMPLES AND DETERMINATION METHODS Samples of t h y m u s D N A were obtained b y a method dissolved earlier [4]. The source of ultrasound was a 3 W / c m a quartz generator. The DNA-DI~aze reaction was carried out in a 0.04 molar solution of tris-HC1, 0.008 molar MgC11 and 0.2 molar NaC1 of p H ~ 7-5. Neither the ultrasonic nor the enzymic destruc* Vysokomol. soyed. 7: No. 11, 2001-2005, 1965.
2189
REFERENCES 1. K. MAYO and M. LEWIS, J. Am. Chem. Soc. 66: 1594, 1944 2. F. T. WALL, J. Am. Chem. Soc. 66: 2050, 1944 3. A. D. ABKIN and S. S. MEDVEDEV, Dokl. Akad. Nauk SSSR 56: 177, 1947
4. A. D. ABK1N and S. S. MEDVEDEV, Trudy 3 Konf, vysokomol, soyed., Izdat. Akad. Nauk SSSR, 1948
CONNECTION BETWEEN THE HETEROPHASE COPOLYCONDENSATION CONSTANTS AND THR ADSORPTION CHARACTERISTICS OF MONOMERS* L. B. SOKOLOV and L. V. TURETSKII Vladimirsk Synthetic Resin Research Institute (Received 5 January 1965)
THE copolymerization method widely used in the chemistry of high polymers can give important information about the mechanism of the reaction components by analysis of the copolymerization constants. The quantitative aspects of the copolycondensation method are not fully developed at present. Although a start was made [1] by publishing information on the calculation of the copolymerization constants for different variants of heterophase copolycondeusations [2-4], the values obtained were only used to draw qualitative conclusions regarding the characteristics of the mechanisms of the respective processes. By using very general theories about the mechanism of the processes occurring at the boundary surface, one can quantitatively assess the physical meaning of the copolycondensation constants of the heterophase variants of the processes (interfacial and gas-phase polycondensation). Where the reaction takes place only at the interface and is not complicated by reactions in space (of the phases), the composition of the copolymer will be determined by the concentrations of reagents A and B present in the reaction zone, i.e. at the interface. When surface-active monomers are used, the concentrations of A and B in the boundary layer will differ from those present in the solution and can be represented by the Boltzman equations [5]:
[A]'=[A] × e-E~/~r
(1)
[B]'--[B] × e -EBlaT
(2)
* Vysokomol. soyed. 7: :No. 11, 1997-2000, 1965.
2190
L.B.
SOKOLOV and L. V. TURETS~-I
where [A] and [B] are the concentrations in the space of the phases, [A]' and [B]' those present in the boundary layer, E a and E~ the changes of the energy potentials of molecules A and B during passage from the aqueous phase to t h e boundary surface, i.e. the reaction zone. One can show, by considering (1) and (2), that the equation for the copolymer composition suggested by [1] and given below as (6), does not change its general shape, except t h a t copolycondensation constant r in it should be understood to mean: r=roe_Cea - E#/m, (3) where r 0 is the true copolycondensation constant determining the ratio of the reaction rate constants of components A and B with a third component. Where A and B are members within a homologous series, equation (3) can be transformed into: r=roe_(~Em~ ~z~, (4) in which z/n is the difference in the n u m b e r of repetitive chain members in molecules A and B, and •E the change of the potential energy during the adsorption of one repetitive chain member. As the eAEmT of an aliphatic series of homologues is known [5] as the constant of the Traube rule, fl, one can write r = r o f l -zn ,
(5)
~n being the difference in the number of CH~-groups of homologues. We have shown [6] that the gas-phase polycondensation is less complicated, compared with intorfacial, by processes taking place in the space of the phases, so that one can verify the picture given above most satisfactorily by analysing the copolycondensation constants at the phase boundary between a liquid and a gas. The Table below lists the copolycondensation constants at the liquid-gas interface (gas-phase polycondensation). It gives the verified results of previous experiments [4] and new ones obtained afterwards. The conditions and results of the copolymcr syntheses were given earlier [4], the methods of polymer synthesis by gas-phase polycondensation in [6, 10]. The values of the polycondensation constants shown in the Table were calculated from equation: [A]/[A0] =([BJ/[B0])'
(6)
where [Ao] and [B0] are the concentrations of components A and B in the reaction mixture at the start, [A] and [B] are those at the end of the test, and r is the experimentally determined copolycondensation constant. The most interesting of the results shown in the Table are those involving systems containing aliphatic diamines, with the exception of ethylenediamine (systems 3-6 in the Table), as far as it concerns quantitative calculations. This
2191
The adsorption characteristics of monomers GAS-PHASE COPOLYCONDENSATION CONSTANTS OF SOME SYSTEMS
System Exp. No.
I) iamines Acid chloride Component A Ethylenediamine Ditto Hexa MD Hexa MD Hexa MD Tetra MD Ethylenediamine Hexa MI) p-Phenylenediamine
r
Component B Hexamethylenediamine I)itto Octa MI) I)eca MD I)eca MI) I)eca MD I)eca MI) Benzidine Benzidine
Copolycondensation constant
Oxalyl chloride Phosgene Oxalyl chloride Oxylal chloride Phosgene Oxalyl chloride Phosgene Oxalyl chloride Oxalyl chloride
0.60 0-57 0.45 0.21 0-20 0.11 0"07 0"23 0.84
MD - methylenediamine.
is because one can say that the reactivities of these diamines must be identical on the basis of their dissociation constants [.4]. Further-more, information is available about t h e Traube rule coefficient under different conditions within an aliphatic series of homologues [7, 8]. B y transforming equation (5) into a logarithmic equation to have it in a suitable form for processing the experimental results, and b y considering An, we obtain: In 1 / r = l n l/re+An × In fl (7) or, since r 0 equals one for systems 3 to 6, In 1/r:An × In ft.
(8)
I t follows from equations (7) and (8) that In 1/r is a linear function of An. The Figure shows the plot of In 1/r against An for copolymer systems in which aiiphatic diamines wore used. One can see good agreement between the above assumption and the experimental results. This confirms that In 1/r is a linear function of An in the series of aliphatic diamines. The above indicates that adsorption processes play an important part in the gas-phase polycondensation and that the reaction takes place mainly at the interface. I t also follows from equations (7) and (8) that the slope of the line in the figure gives Traube coefficient in an aliphatic series of homologues. Using this slope, the Traube coefficient was found to be 1.5, i.e. identical with that given in the literature. In should be noted that the literature does not contain any information about the Traube coefficient, as determined under our experimental conditions (bifunctional compounds, 90°C). It was also reported [7] that the T~aube coefficient
2192
L. B, SoxoLov and L. V. TURETSKII
approached unity on increasing the temperature; p~-2.7 [8] for bifunctional aliphatic compounds at 20°C. The diagram shows also a deviation from In 1/r being a function of An where systems of copolymers, in which ethylenediamine was used for the synthesis, were involved. This deviation can probably be explained by the different reactivity of ethylenediamine compared with other diamines within the series of homologues (see the values of the dissociation constants of the respective diamines in [4]), and also for other reasons.
oa
2
54
6
l 4
,
1
0
I
An
8
1/r as a function of ztn for copolymer systems obtained by using aliphatic diamines: a--systems with higher aliphatic diamines; b--systems with ethylenediamine. The numbers against the points are identical with those given in the Table.
We have thus a quantitative picture of the characteristics of the gas phase polycondensation of binary mixtures of diamines. It should be noted that the present case of the effect of adsorption of the reagents during this heterophase polycondensation was the simplest of all. It is very likely that the observed characteristics will also be found for other cases of heterophase polycondensation, especially those at the interface of two liquids. It is worth remembering that the above picture of the part played by adsorption during polycondensation at the interface is identical with that given by others [9] who studied the reaction with low molecular weight surfactants in boundary surface conditions. CONCLUSIONS
(1) A quantitative relation between the constants of copolycondensation and the adsorption characteristics of monomers in gas-phase reactions is given. (2) The experimentally found Traube coefficient for CH~-groups was identical with that given in the literature, which was obtained from surface tension measurements. Translated by K. A. ALLEN
Flow birefringenee of D N A molecules
2193
REFERENCES 1. L. B. SOKOLOV and T. L. KRUgLOVA, Vysokomol. soyed. 2: 704, 1960 2. V. V. KORSHAK, T. M. FRUNZE and L. V. KOZLOV, Izvest. Akad. N a u k SSSR, Otd. k_him. Nauk, 2062, 1962 3. V. V. KORSHAK, T. M. FRUNZE and L. V. KOZLOV, Izvest. Akad. N a u k SSSR, Otd. khim. Nauk, 2226, 1962 4. L. V. TURETSKII, L. B. SOKOLOV and V. Z. NIKONOV, Sb. Geterotsepnye vysokomolekularnye soyedineniya. (in: "Heterochain High Polymers".) Izdat. " N a u k a " 107, 1964 5. S. M. LIPATOV, Fiziko-khimiya kolloidov. (The Physical Chemistry of Colloids.) Gos. Khim. Izdat., 1948 6. L. B. SOKOLOV and L. V. TURETSKII, Vysokomol. soyed. 6: 346, 1964 7. P. REHBINDER, Z. phys. Chem. 111: 447, 1924 8. A. B. TAUBMAN, Dissertation, 285, 1948 9. A. A. ABRAMZOV, Yu. L. KIYANOVSKAYA and L. Ya.' KREMNEV, Zhur. priklad. Khim. 37: 2314, 1964 10. L. B. SOKOLOV, T. V. KUDIM and L. V. TURETSKH, Vysokomol. soyed. 3: 1370, 1961
FLOW BIREFRINGENCE AND FLEXIRILITY OF DESOXYRIBONUCLEIC ACID (DNA) MOLECULES* V. N . T S V E T K O V , L . N . A N D R E Y E V A a n d L . N . K V I T C H E N K O H i g h Polymer Institute, U.S.S.R. A c a d e m y of Sciences
(Received 10 March 1965)
OUR previous works [1, 2] reported the study of An and the directional angle of the flow birefringenee of DNA fragments obtained by ultrasonic disintegration. It showed that the difference between the main polarizations, 71--72, of DNA molecules increased with the molecular weight of the sample, M, in accordance with the optical propetries of the semi-rigid chains [3]. To obtain quantitative data on the flexibility of DNA molecules, we continued our dynamic flow birefringenee experiments and also extended these to a larger number of samples, and over a wider range of molecular weights. The DNA fragments were obtained by subjecting DNA solutions to ultrasonic and enzymic disintegration. SAMPLES AND DETERMINATION METHODS Samples of t h y m u s D N A were obtained b y a method dissolved earlier [4]. The source of ultrasound was a 3 W / c m a quartz generator. The DNA-DI~aze reaction was carried out in a 0.04 molar solution of tris-HC1, 0.008 molar MgC11 and 0.2 molar NaC1 of p H ~ 7-5. Neither the ultrasonic nor the enzymic destruc* Vysokomol. soyed. 7: No. 11, 2001-2005, 1965.