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High-molecular derivatives of α-methylstyrene—II. Chloromethylation of copolymers of α-methylstyrene and divinylbenzene
HIGH-MOLECULAR DERIVATIVES OF a-METHYLSTYRENE--II. CHLOROMETHYLATION OF COPOLYMERS OF a-METHYLSTYRENE AND DIVINYLBENZENE* A. B. DAVANKOV, I. SANTO and P. M. LILO I). [. Mendeleyev Chemico-Technological Institute, Moscow (Receiced 26 August 1961) CHLOROMETHYLATION is an important reaction in organic synthesis. It provides a means of carrying out many conversions in the polymer field with various synthetic, linear, network and three-dimensional po!ymers. Examples of this are the polystyrene derivatives produced on the industrial scale, and used as starting materials for the production of ion- and electron-exchange materials. Aromatic compounds containing chloromethyl groups are distinctive in their high reactivity resulting from the lability of the chlorine atoms. Thus benzyl chloride is used as an agent for benzylating synthetic amines :and alcohols (polyvinylalcohol) [1-3], and natural materials (cellulese). I t can be obtained either b y ordinary chlorination of toluene under suitable conditions, or b y chloromethylation of benzene with monochloromethyl ether [4] or dichloromethyl ether in the presence of Friedel-Krafts cataiysts [5]. The chloromethyl ethers are toxic and comparatively volatile. For this reason chloromethylation in suitable solvents with paraformaldehyde, hydrogen chloride and zinc chloride, according to the method of Blanc, has certain advantages over the usual methods of chloromethylation with chloromethyl ethers. The chloromethylation of polystyrene and of copolymers of styrene with divinylbenzene and other "crosslinking agents" has been decribed in the literature [6-8]: The purpose of the present work was to make a detailed study of the chloromethylation of copolymers of ~-methylstyrene with dienes. T h e s e differ from polymers and copolymers of styrene, which are more complex in spatial structure and properties. The factors taken into consideration in setting up this work were that this process had not been studied and that there was a possibility that the special features of the spatial structure of the cop01ymers would have an effect when labile chlorine atoms are introduced into their structure and in subsequent substitution of the chlorine by the amino group. Copolymers of a-methylstyrene and divinylbenzene were chloromethylated by freshly distilled monochloromethyl ether of b.p. 58-60 and n D 1.387. Granules of a copolymer of these monomers of diameter 0.5-1.0 mm were placed in a three* Vysokomol. soyed. 5: No. 2. 238-242, 1963. 859
860
A.B. DAVANKOVet al.
necked flask, provided with a reflux condenser and mechanical stirrer, and allowed to swell in monochlorcmethyl ether for 12-14 hours at room temperature. After this the required quantity of a solution (or weighed quantity) of the catalyst in monochloromethyl ether was added and the mixture was heated at 60 ° for 4--6 hours, with vigorous stirring. The catalysts used were ZnCl2, AICl3, SnC14 and SnCI 2. The granules were filtered off, washed first with methanol and then with distilled water until the filtrate was completely free from chlorine ions, and dried to constant weight at 60-70 ° . The chloromethylation reaction was as follows:
•.. -C--CH~ . . . .
I
~H--CH
2 - -
"
•
"
CICH~OCH{*:~ -('H~
. . .
I
' ~
I , (' ~ C- ('Hi . . .i. . . H- -CH~ -- ....CH~
..
.
()C
I
-
CH2CI
\(:':11
-CH
_ ?}
T h e chlorine content of the end products was determined by Schiff's modification o f Liebig's method [9], b y combustion in an excess of calcium oxide. Results on the chloromethylation of an a-methylstyrene-divinylbel~zene copolymer (6% DVB) at 60 ° for 6 hours with a ratio of copolymer to monochloromethyl ether of 1:7.5, are shown graphically in Fig. 1. The graphs show that with increasing content of catalyst in the reaction mixture the chlorine content of the chloromethylated copolymer increases, reaching 13.6-17.5°/o, which corresponds to 64-88~/o chemical conversion of the copolymer to the chloromethylated derivative. Best results were obtained with stannic chloride as catalyst• An increase in the catalyst content beyond 0.3-0.4 moles per benzene nucleus in the copolymer produces only a slight increase in the chlorine content of the reaction product. This is possibly a consequence of side reactions leading to the splitting off of HCl and the formation of a closer network structure, as observed by Jones [6] in the chloromethylation of polystyrene. In addition to the study of the effect of the nature and concentration of the catalyst a study was made of the effect of temperature on the chloromethylation ~ f the copolymer (6~/o DVB). The dependence of the chlorine content, of the
High-molecular derivatives of ~-mcthylstyrene--II ~
86I
ZnCL 2
n CL4
18 14 12 10 ~
8
"~.
0
'
0'.2
0:4 ' 0:6 moles catalyst moles copolgmer
'
0'8
FIG. 1. Dependence of the chlorine content of chloromethylated ~-MST/DVB copolymers on the nature and quantity of the catalyst. Reaction time 6 hours temperature 60°, DVB content of copolymer 6 %, diameter of granules 0.5 mm; ratio -- 7.5 moles of monochloromethyl ether per base mole of copolymer. copolymer on the temperature of chloromethylation is shown graphically in Fig. 2~ It is seen that with increasing reaction temperature the chlorine content of the copolymer increases, reaching the maximum at the boiling point of monochloromethyl ether (58-60°). The degree of chemical conversion in this case is 7 9 . 4 ~ of theory. A study of the effect of reaction time on the chlorine content of the copolymer showed that at 20 ° after four days the chlorine content was only 9 . 5 ~ (degree of conversions 44.6~/o) , whereas at 60 ° after 6 hours the chlorine content of the copolymer (containing 10% of DVB) was 14.9% (66.2% conversion). The graph shown in Fig. 3 indicates that ehloromethylation of the copolymer ( 1 0 ~ D V B ) at 60 ° in the presence of SnC14 proceeds very vigorously for the first 6-8 hours. Subsequently the rate of increase in the chlorine content of the end product falls off. The rate of chloromethylation is dependent not only on temperature, b u t also o n the number of crosslinkages in the copolymer, as is shown b y the results given in the Table. Other factors being equal, the quantity of chlorine entering:
862
A . B . D),V),NKOV et al.
the molecular network in unit time is less the greater the degree of crosslinking of the copolymer chains. This is evidently associated with the lower degree of DEPENDENCE
OF T H E C H L O R I N E CONTENT OF C H L O R O M E T H Y L A T E D COPOLYMERS
O F ~ - M E T I I Y L S T Y E E N E A N D D I V I N Y L B E N Z E N E ON 3'HE Q U A N T I T Y O F
DVB
IN THE
COPOLYMERS
(Reactants, 2 g of copolymer and 16 ml of monochloromethyl ether temperature 60 °) DVB content of copolymer
Catalyst (g)
(%)
SnC]=
4 6 8 l0 4 6 8 10 4 6 8 l0 4 6
0.6 0.6 0.6 0.6
SnC1a
Time (hours)
ZnC]~
0.4 0.4 0.4 0-4 0.8 0.8 0.8 0.8
Chlorine content
(%) 15"4 13"6 11"0 10"4 17'0 14"0 12"0 10"2 17"5 17"] 17"0 15"0 17"0 15"0
L
L
0"6 0'6
swelling in organic solvents of copolymers with a large number of crosslinkages, and consequently with the lower accessibility of the reactive groups of the eopolymer for intereetion with the molecules of monochloromethyl ether. 16 - , 14
12 "~ I0
12
~6
"% L,. 8
ge
~2
g
Temperature (°C)
FIG. 2. Dependence of the chlorine content of ehloromethylated ~-MST/DVB copolymers on reaction temperature.
4
Time (hours)
I0
12
FIG. 3. Dependence of chlorine content on time of t r eat m en t of ~-MST/DVB copolymer with monoehloromethyl ether.
High-molecular derivatives of u-methylstyrene- II
863
The chlorine content of the chloromethylated copolymers is dependent not only on the reaction temperature and time, and the nature and quantity of the catalyst, but also on the size of the copolymer granules and on the molar ratio of the reactants. This is supported b y the experimental results depicted graphically in Fig. 4 and 5.With decreasing quantity of monochloromethyl ether and increasing diameter of the copolymer gramdes the degree of chloromethylation decreases. 16
/4
@. 12.4 "" 12.0
~11.6 ~ 17.2
10 8
/0.4 Io.o o
1 .
Oiorneter of granules (rnm)
FIG. 4. Dependence of chlorine content on size of ~-MST/DVB eopolymer granules.
t
,
0 5 I0 15 mo~es monochlorernethql ether moles catalyst
i_
FIG. 5. Dependence of chlorine content on the number of moles of monochloromethy et her per ~-MST/DVB copolymer base mole
The investigation showed that granular copolymers of a-methylstyrene and divinylbenzene can be chloromethylated in 6-8 hours at 60 ° in the presence of 0.4-0.5 moles of SnC14, SnCI~, ZnC12, or A1CIa and 12-15 moles of monochloromethyl ether per base mole of copolymer. The degree of chemical conversion under these conditions is 70-80%. Chloromethylation by Blanc's method under similar condition did not give the desired result. The degree of chemical conversion in this case was only 450-6% of the theoretical figure. CONCLUSIONS
A study has been made of the ehloromethylation of copolymers of a-methylstyrene and divinylbenzene. The molar ratios of the reactants have been established. The optimal reaction time and temperature for chloromethylation in the presence of SnCI4, SnC12, ZnC12 and A1C1a was found. The degree of chemical conversion of the copolymers to the corresponding chlorine derivatives was
70-80%. Translated by E. O. PHILLIPS
864
I. A. MAIQEL*DINOV and K. I. TSYUR REFERENCES
1. S. N. USHAKOV and Ye. M. LAVRENT’EVA,
Zh. prikl. khim. 26: 960, 1953 2. A. B. DAVANKOV and D. A. DAVANKOVA, Issledovanie v oblasti vysokomolekularnykh soedinenii. (Studies in the Field of Macromolecular Compounds.) Trudy MKhTI im. D. I. Mendeleyeva, 29: 99, 1959 3. A. B. DAVANKOV, L. B. ZUBAKOVA and A. B, ANTONOVA, Zh. prikl. khim. 34: 1110, 1961 organicheskaya khimiya. (Preparative Organic Chemistry.) p. .321 4. Preparativnaya Goskhimizdat, 1959 5. H. STEPHEN, W. SHORT and 6. GLADDING, J. Chem. Sot. 510, 1920 6. T. JONES, Ind. Eng. Chem. 44: 2686, 1952 7. H. W. PEPPER, IL M. PAISLEY and M. A. YOUNG, J. Chem. Sot. 57, 1953 8. LI SAN-ZHAO, Dissertation, Moscow, MKhTI im D. I. Mendeleyeva, 1960 9. J. THORPE and M. A. WHITELY, Prakticheskoe rukovodstvo po organicheskomu analizu. (Practical Handbook of Organic Analysis.) p. 59, United Scientific and Technical Press (Russian translation) 1937
THE THERMOMECHANICAL PROPERTIES OF CRYSTALLINE POLYMERS-I. POLYETHYLENE* I. A. MAIGEL’DINOV State Scientific-Research
and K. I. TSYUR
Institute of Synthetic Plastics
(Received 26 August 1961) THE method of investigation of polymers by determination of their thermomeohanical charac teristics, proposed by Kargin.[l], has become firmly established in laboratory practice and occupies a prominent position in modern polymer science 12-41. The main feature of this method, apart from its simplicity, is that it not only characterizes the properties and molecular structure of the polymer (for example the rigidity of the chain and length of the segment but also shows a direct connection between structure and properties of practical importance. Up to the present time this method has been used mainly for the study of amorphous polymers. In the present work the thermomechanical method was used for the characterization and study of the structure of polymers in the crystalline state, in particular for finding Tg and other transition temperatures of crystalline polymers, for estimating the degree of crosslinking, the deficiency of the crystalline structure etc. This work is concerned with the investigation of the deformation properties (elasticity modulus) of polyethylene in relation to the proportion of non-crystalline structure and degree of branching, and also in relation to external factors - temperature and time of storege of the specimens. The conection between the elasticity modulus (E) of polyethylene and its structure was established on the basis of an analysis of the results of tests on several hundred commercial * Vysokomol.
soyed. 5: No. 2, 243-251, 1963.
860
A.B. DAVANKOVet al.
necked flask, provided with a reflux condenser and mechanical stirrer, and allowed to swell in monochlorcmethyl ether for 12-14 hours at room temperature. After this the required quantity of a solution (or weighed quantity) of the catalyst in monochloromethyl ether was added and the mixture was heated at 60 ° for 4--6 hours, with vigorous stirring. The catalysts used were ZnCl2, AICl3, SnC14 and SnCI 2. The granules were filtered off, washed first with methanol and then with distilled water until the filtrate was completely free from chlorine ions, and dried to constant weight at 60-70 ° . The chloromethylation reaction was as follows:
•.. -C--CH~ . . . .
I
~H--CH
2 - -
"
•
"
CICH~OCH{*:~ -('H~
. . .
I
' ~
I , (' ~ C- ('Hi . . .i. . . H- -CH~ -- ....CH~
..
.
()C
I
-
CH2CI
\(:':11
-CH
_ ?}
T h e chlorine content of the end products was determined by Schiff's modification o f Liebig's method [9], b y combustion in an excess of calcium oxide. Results on the chloromethylation of an a-methylstyrene-divinylbel~zene copolymer (6% DVB) at 60 ° for 6 hours with a ratio of copolymer to monochloromethyl ether of 1:7.5, are shown graphically in Fig. 1. The graphs show that with increasing content of catalyst in the reaction mixture the chlorine content of the chloromethylated copolymer increases, reaching 13.6-17.5°/o, which corresponds to 64-88~/o chemical conversion of the copolymer to the chloromethylated derivative. Best results were obtained with stannic chloride as catalyst• An increase in the catalyst content beyond 0.3-0.4 moles per benzene nucleus in the copolymer produces only a slight increase in the chlorine content of the reaction product. This is possibly a consequence of side reactions leading to the splitting off of HCl and the formation of a closer network structure, as observed by Jones [6] in the chloromethylation of polystyrene. In addition to the study of the effect of the nature and concentration of the catalyst a study was made of the effect of temperature on the chloromethylation ~ f the copolymer (6~/o DVB). The dependence of the chlorine content, of the
High-molecular derivatives of ~-mcthylstyrene--II ~
86I
ZnCL 2
n CL4
18 14 12 10 ~
8
"~.
0
'
0'.2
0:4 ' 0:6 moles catalyst moles copolgmer
'
0'8
FIG. 1. Dependence of the chlorine content of chloromethylated ~-MST/DVB copolymers on the nature and quantity of the catalyst. Reaction time 6 hours temperature 60°, DVB content of copolymer 6 %, diameter of granules 0.5 mm; ratio -- 7.5 moles of monochloromethyl ether per base mole of copolymer. copolymer on the temperature of chloromethylation is shown graphically in Fig. 2~ It is seen that with increasing reaction temperature the chlorine content of the copolymer increases, reaching the maximum at the boiling point of monochloromethyl ether (58-60°). The degree of chemical conversion in this case is 7 9 . 4 ~ of theory. A study of the effect of reaction time on the chlorine content of the copolymer showed that at 20 ° after four days the chlorine content was only 9 . 5 ~ (degree of conversions 44.6~/o) , whereas at 60 ° after 6 hours the chlorine content of the copolymer (containing 10% of DVB) was 14.9% (66.2% conversion). The graph shown in Fig. 3 indicates that ehloromethylation of the copolymer ( 1 0 ~ D V B ) at 60 ° in the presence of SnC14 proceeds very vigorously for the first 6-8 hours. Subsequently the rate of increase in the chlorine content of the end product falls off. The rate of chloromethylation is dependent not only on temperature, b u t also o n the number of crosslinkages in the copolymer, as is shown b y the results given in the Table. Other factors being equal, the quantity of chlorine entering:
862
A . B . D),V),NKOV et al.
the molecular network in unit time is less the greater the degree of crosslinking of the copolymer chains. This is evidently associated with the lower degree of DEPENDENCE
OF T H E C H L O R I N E CONTENT OF C H L O R O M E T H Y L A T E D COPOLYMERS
O F ~ - M E T I I Y L S T Y E E N E A N D D I V I N Y L B E N Z E N E ON 3'HE Q U A N T I T Y O F
DVB
IN THE
COPOLYMERS
(Reactants, 2 g of copolymer and 16 ml of monochloromethyl ether temperature 60 °) DVB content of copolymer
Catalyst (g)
(%)
SnC]=
4 6 8 l0 4 6 8 10 4 6 8 l0 4 6
0.6 0.6 0.6 0.6
SnC1a
Time (hours)
ZnC]~
0.4 0.4 0.4 0-4 0.8 0.8 0.8 0.8
Chlorine content
(%) 15"4 13"6 11"0 10"4 17'0 14"0 12"0 10"2 17"5 17"] 17"0 15"0 17"0 15"0
L
L
0"6 0'6
swelling in organic solvents of copolymers with a large number of crosslinkages, and consequently with the lower accessibility of the reactive groups of the eopolymer for intereetion with the molecules of monochloromethyl ether. 16 - , 14
12 "~ I0
12
~6
"% L,. 8
ge
~2
g
Temperature (°C)
FIG. 2. Dependence of the chlorine content of ehloromethylated ~-MST/DVB copolymers on reaction temperature.
4
Time (hours)
I0
12
FIG. 3. Dependence of chlorine content on time of t r eat m en t of ~-MST/DVB copolymer with monoehloromethyl ether.
High-molecular derivatives of u-methylstyrene- II
863
The chlorine content of the chloromethylated copolymers is dependent not only on the reaction temperature and time, and the nature and quantity of the catalyst, but also on the size of the copolymer granules and on the molar ratio of the reactants. This is supported b y the experimental results depicted graphically in Fig. 4 and 5.With decreasing quantity of monochloromethyl ether and increasing diameter of the copolymer gramdes the degree of chloromethylation decreases. 16
/4
@. 12.4 "" 12.0
~11.6 ~ 17.2
10 8
/0.4 Io.o o
1 .
Oiorneter of granules (rnm)
FIG. 4. Dependence of chlorine content on size of ~-MST/DVB eopolymer granules.
t
,
0 5 I0 15 mo~es monochlorernethql ether moles catalyst
i_
FIG. 5. Dependence of chlorine content on the number of moles of monochloromethy et her per ~-MST/DVB copolymer base mole
The investigation showed that granular copolymers of a-methylstyrene and divinylbenzene can be chloromethylated in 6-8 hours at 60 ° in the presence of 0.4-0.5 moles of SnC14, SnCI~, ZnC12, or A1CIa and 12-15 moles of monochloromethyl ether per base mole of copolymer. The degree of chemical conversion under these conditions is 70-80%. Chloromethylation by Blanc's method under similar condition did not give the desired result. The degree of chemical conversion in this case was only 450-6% of the theoretical figure. CONCLUSIONS
A study has been made of the ehloromethylation of copolymers of a-methylstyrene and divinylbenzene. The molar ratios of the reactants have been established. The optimal reaction time and temperature for chloromethylation in the presence of SnCI4, SnC12, ZnC12 and A1C1a was found. The degree of chemical conversion of the copolymers to the corresponding chlorine derivatives was
70-80%. Translated by E. O. PHILLIPS
864
I. A. MAIQEL*DINOV and K. I. TSYUR REFERENCES
1. S. N. USHAKOV and Ye. M. LAVRENT’EVA,
Zh. prikl. khim. 26: 960, 1953 2. A. B. DAVANKOV and D. A. DAVANKOVA, Issledovanie v oblasti vysokomolekularnykh soedinenii. (Studies in the Field of Macromolecular Compounds.) Trudy MKhTI im. D. I. Mendeleyeva, 29: 99, 1959 3. A. B. DAVANKOV, L. B. ZUBAKOVA and A. B, ANTONOVA, Zh. prikl. khim. 34: 1110, 1961 organicheskaya khimiya. (Preparative Organic Chemistry.) p. .321 4. Preparativnaya Goskhimizdat, 1959 5. H. STEPHEN, W. SHORT and 6. GLADDING, J. Chem. Sot. 510, 1920 6. T. JONES, Ind. Eng. Chem. 44: 2686, 1952 7. H. W. PEPPER, IL M. PAISLEY and M. A. YOUNG, J. Chem. Sot. 57, 1953 8. LI SAN-ZHAO, Dissertation, Moscow, MKhTI im D. I. Mendeleyeva, 1960 9. J. THORPE and M. A. WHITELY, Prakticheskoe rukovodstvo po organicheskomu analizu. (Practical Handbook of Organic Analysis.) p. 59, United Scientific and Technical Press (Russian translation) 1937
THE THERMOMECHANICAL PROPERTIES OF CRYSTALLINE POLYMERS-I. POLYETHYLENE* I. A. MAIGEL’DINOV State Scientific-Research
and K. I. TSYUR
Institute of Synthetic Plastics
(Received 26 August 1961) THE method of investigation of polymers by determination of their thermomeohanical charac teristics, proposed by Kargin.[l], has become firmly established in laboratory practice and occupies a prominent position in modern polymer science 12-41. The main feature of this method, apart from its simplicity, is that it not only characterizes the properties and molecular structure of the polymer (for example the rigidity of the chain and length of the segment but also shows a direct connection between structure and properties of practical importance. Up to the present time this method has been used mainly for the study of amorphous polymers. In the present work the thermomechanical method was used for the characterization and study of the structure of polymers in the crystalline state, in particular for finding Tg and other transition temperatures of crystalline polymers, for estimating the degree of crosslinking, the deficiency of the crystalline structure etc. This work is concerned with the investigation of the deformation properties (elasticity modulus) of polyethylene in relation to the proportion of non-crystalline structure and degree of branching, and also in relation to external factors - temperature and time of storege of the specimens. The conection between the elasticity modulus (E) of polyethylene and its structure was established on the basis of an analysis of the results of tests on several hundred commercial * Vysokomol.
soyed. 5: No. 2, 243-251, 1963.