Metal 4, 4', 4", 4"'=tetracarboxylic phthalocyanines (MPTC) are prepared by reaction of trimellitic anhydride, a salt or hydroxide of the desired metal (or the metal in powdered form), urea and a catalyst. A purer form of MPTC is prepared than heretofore. These tetracarboxylic acids are then polymerized by heat to sheet polymers which have superior heat and oxidation resistance. The metal is preferably a divalent metal having an atomic radius close to 1.35A

Achar, B. N.

Fohlen, G. M.

Parker, J. A.

English

A method of forming 4,4',4'',4''' -tetraamino phthalocyanines involves reducing 4,4',4'',4''' -tetranitro phthalocyanines, polymerizing the metal tetraamino phthalocyanines with a tetracarboxylic dianhydride (preferably aromatic) or copolymerizing with a tetracarboxylic dianhydride and a diamine (preferably also aromatic) to produce amic acids which are then dehydrocyclized to imides. Thermally and oxidatively stable polymers result which form tough, flexible films, varnishes, adhesives, and fibers

NASA Technical Reports Server

Phthalocyanine polymers

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Space Administration 
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https://ntrs.nasa.gov/search.jsp?R=19840019815 2020-03-22T09:32:58+00:00Z
*-- 
United States Patent 
Achar et al. 
r 191 
[54] METAL P-ANINE POLYMERS 
[75] Inventors: Bappalige N. Achar, Mysore, India, 
George M. Fohlen, Millbrae; John A. 
Parker, Los Altos, both of Calif. 
[73] Assignee: The United States of America as 
represented by the Administrator of 
the National Aeronautics and Space 
Administration, Washington, D.C. 
[21] Appl. No.: 415,880 
[22] Filed Sep. 8,1982 
[51] Int. Cl.3 .............................................. CO8G 73/00 
[52] U.S. 43. .................................... 528/327; 528/271; 
528/310; 528/331; 528/362 
[58] Field of Search ............... 528/327, 310, 271, 362, 
528/331 
[561 References Cited 
U.S. PATENT DOCUMENTS 
4,304,719 12/1981 Wynne et al. ....................... 528/362 
Primary Examiner-Harold D. Anderson 
Attorney, Agent, or Firm-Darrell G. Brekke; John R. 
Manning; Robert D. Marchant 
[111 4,450,268 
[45] m y  22, 1984 
[571 ABSTRAGI: 
The invention relates to metal, primarily divalent metal 
such as divalent copper, cobalt and nickel, 4,4',4", 4"' 
phthalocyanine tetracarboxylic acids and to polymers 
prepared by heating the same, and to a method of pre- 
paring the tetracarboxylic acids. 
A method is provided for preparing the aforesaid tetra- 
carboxylic acids in purer form than heretofore. Upon 
heating these acids decarboxylate and produce poly- 
mers. 
These polymers have diphenyl (conjugated) types of 
linkage; they are thermally and oxidatively stable and 
useful as sheet polymers for various purposes such as 
heat shielding. 
The monomeric tetracarboxylic acid is shown in FIG. 
1, the polymer in FIG. 2 and thermal resistance in FIG. 
3. 
The monomeric tetracarboxylic acids are prepared in 
purer form than heretofore, the resulting polymers are 
more stable thermally and oxidatively than metal phtha- 
locyanine polymers and monomers heretofore made. 
12 Claims, 3 Drawing Figures 
- I  
UaSa Patent May 22, 1984 Sheet 1 of 3 4,450,268 
COOH 
FIG. 1 
U.S. Patent May22,1984 Sheet 2 of 3 4,450,268 
M =  Cu, Co. Ni, ... 
FIG. 2 
-9 
U.S. Patent May 22,1984 Sheet 3 of 3 4,450,268 
--\ I 1 
00 
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t a 
W 
3 
W a 
1 
W 
0 ) -  
- 0  
Q 
0 
- 0  
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- 0  
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-4, 
SSOl 1H913M X 
4,450,268 
1 
MEXAL PHTHALOCYANINE POLYMERS 
DESCRIPTION 
ORIGIN O F  THE INVENTION 
The invention described herein was made in the per- 
formance of work under a NASA contract and is sub- 
ject to the provisions of Section 305 of the National 
Aeronautics and Space Act of 1958, Public Law 85-568 
(72 Stat. 435; 42 U.S.C. 2457). 
FIELD OF THE INVENTION 
This invention relates to metal phthalocyanine tetra- 
carboxylic acids, to a novel method of synthesizing the 
same and to polymers of the same. 
BACKGROUND OF THE INVENTION 
In recent years there has been an increasing demand 
in industry and defense for polymeric substances which 
would either remain intact or continue to serve in a 
more or less degraded state under conditions where 
temperatures far above the ordinary are encountered. In 
many cases highly cross-linked organic polymers have 
been found promising. The phthalocyanine structure is 
one of the most thermally stable organic structures 
known. Attractive properties like resistance to chemical 
attack, electrical properties, catalytic activity and mod- 
erate cost of manufacture with good coloring properties 
have made phthalocyanines the object of intensive 
world-wide investigations. Many attempts to synthesize 
polymers based on phthalocyanines have failed to pro- 
vide the expected thermal stability. Phthalocyanine 
polymers so far produced have shown less thermal 
stability than the phthalocyanine monomer itself be- 
cause of the presence of impurities, weak chemical 
bonds and low degree of polymerization with structural 
inhomogeneity. Impurities have the considerable effect 
of decreasing thermal stability of the phthalocyanine 
monomers as well as the polymers produced from them. 
It is well known that the way in which the repeating 
units are linked is reflected in the properties of the poly- 
mers. If the repeating phthalocyanine mer units are 
linked in the way phenyl groups are linked in biphenyl, 
the conjugation extends throughout the macromolecule 
thereby increasing the extend of delocalization of the 
m-electrons. This is expected to increase the conductiv- 
ity as well as the thermal stability of the phthalocyanine 
polymers. 
OBJECTS OF THE INVENTION 
Objects of the invention include methods of prepar- 
ing metal phthalocyanine monomers in a pure state and 
the preparation from such monomers of thermally sta- 
ble sheet polymers which have biphenyl type linkages 
between the mer units, high thermal and thermal oxida- 
tive stability and electrical conductivity, also good 
flame and fire resistance. 
BRIEF DESCRIPTION OF THE INVENTION 
A metal phthalocyanine tetracarboxylic acid 
(MPTC) is prepared in pure form by reaction of trimel- 
litic anhydride with urea and a soluble metal salt in the 
presence of a suitable catalyst and in a suitable solvent. 
The metal is that which it is desired to introduce into 
2 
than MPTC's prepared heretofore and the polymer 
derived from it is free of impurities which detract from 
its useful properties. 
5 DESCRIPTION OF THE DRAWINGS 
FIG. 1 is a structural formula of the metal 4,4',4",4"'- 
tetracarboxy phthalocyanine which is to be polymer- 
ized. 
FIG. 2 is a structural formula of the resulting poly- 
10 mer. 
FIG. 3 is a graph showing TGA and DTG curves for 
these polymers, including the polymer of FIG. 2. 
DETAILED DESCRIPTION OF THE 
15 INVENTION 
EXAMPLE 1 
Preparation of Copper (11) phthalocyanine 
tetracarboxylic acid 1 
2o This compound has the formula 
30 
35 
HOOC 1 
25 
40 
wherein M is copper 01). 
It was prepared as follows: 12.0 g Copper (11) sulfate 
pentahydrate, 33.8 g trimellitic anhydride, 4.5 g ammo- 
nium chloride, 0.5 g ammonium molybdate and 60 g 
urea were finely ground together and placed in a 500 ml 
three-necked flask containing 25 ml of nitrobenzene. 
50 The flask was provided with a thermometer, condenser 
and a mechanical stirrer. The temperature of the flask 
was slowly increased to 180" C. and maintained at 185" 
6. for four hours. The color of the reaction mixture 
55 gradually deepened and finally a deep colored solid was 
obtained. The product was ground well and washed 
with methanol until it was free from nitrobenzene. The 
solid product was added to 500 ml of LON hydrochloric 
acid saturated with sodium chloride, boiled briefly, 
60 cooled to room temperature and filtered. The resulting 
solid material was treated with 500 ml of 2.0N sodium 
hydroxide containing 200 g sodium chloride and heated 
at 90" C. until the evolution of ammonia ceased. The 
solution after filtration was treated with 500 ml 2.0N 
45 
the intended metal complex. The resulting MPTC, after 65 hydrochloric acid and the product was separated by 
separation and purification, is polymerized by heat in a centrifugation. The residue was redissolved in 0.1N 
vacuum or in an atmosphere of an inert gas such as sodium hydroxide and filtered to separate the insoluble 
nitrogen. The MPTC prepared by this method is purer materials. The compound was re-precipitated with 1.ON 
3 
4,450,268 
4 
hydrochloric acid and centrifuged to obtain the solid 
material. Dissolution and precipitation steps were re- 
peated twice. Then the compound was washed until 
chloride free and finally washed with methanol. The 
blue product was dried at 100" in vacuum. 
Compound c36I16&08Cu, (CuPTC): calcd: C, 57.5; 
H, 2.14; N, 14.9; Cu, 8.45; Eq. wt. 188.0, Found: C, 57.1; 
H, 2.3; N, 15.0; Cu, 8.5; Eq. wt. 187.6. IR absorption 
bands (cm-1) 3500-2500 (broad), 1691 (broad), 1614m, 
1578m, 1508m, 1329m, 1279m, 1246m (broad), 1188m, 
1149m, 1089s, 105Ow, 968w, 94Ow, 851w, 783w, 774w, 
736s. 
EXAMPLES 2 AND 3 
The cobalt and nickel analogues of 1 were prepared 
by the same method using in Example 2 cobalt sulfate 
and in Example 3 nickel sulfate. The empirical formulae 
and analytical results obtained were as follows: 
EXAMPLE 2 (Cobalt) 
Compound C36H16N8Og&, (CoPTC): calcd: c, 57.8; 
H, 2.15; N, 15.0; Co, 7.88; Eq. wt. 186.9, found: C, 57.5; 
H, 2.2; N, 15.2; Co, 7.90; Eq. wt. 186.7. IR absorption 
bands (cm-I): 3500-2500 (broad), 1696 (broad), 1613m, 
1586m, 1521m, 133Om, 1281m, 1246m (broad), 1189m, 
1149m, 109Os, 1050w, 9730w, 944w, 848w, 782w, 773w, 
742s. 
EXAMPLE 3 (Nickel) 
Compound C36&N80sNi, (NiPTC): calcd: c, 
57.86;H,2.15;N, 15.0;Ni,7.86;Eq.wt. 186.8,found:C, 
57.91; H, 2.2; N, 15.05; Ni, 7.88; Eq. wt. 186.6. IR ab- 
sorption bands (cm-1): 3500-2500 (broad), 1699 
(broad), 1615m, 159Om, 153Om, 1333m, 1274m, 1238m 
(broad), 1189m, 115Om, 1089% 1050w, 976w, 944w, 
848w, 779w, 738s. 
Any mono-, di- or higher valency metal M may be 
used in place of divalent copper, cobalt and nickel, e.g., 
Cu(I), cobalt and nickel in other valence states, Fe(II), 
Fe(III), Zn, Al, lead, tin, palladium, germanium, vana- 
dium, platinum and molybdenum in various valence 
states; monovalent metals such as Li, Na and K, etc. 
Where the metal is monovalent two atoms will be pres- 
ent, one atom above and the other atom below the plane 
of the phthalocyanine molecule. With a trivalent metal 
such as aluminum, one of the valences may be satisfied 
by a ligand such as C1, F, acetate, etc., e.g., the metallic 
component can be represented as M X  where M' is the 
metal atom and X is an inorganic atom or radical or an 
organic group. 
Preferably the metal is divalent and has an atomic 
radius close to 1.35 A. Metals of substantially larger 
atomic radius may not fit well into the molecule and 
metals having a substantially smaller atomic radius are 
more likely to be extracted by strong acids, e.g., con- 
centrated sulfuric acid. Metals having ligands may be 
susceptible to hydrolytic action. 
Any soluble salt or hydroxide of the selected metal 
5 
10 
15 
20 
25 
30 
35 
40 
45 
0 
(which provides the benzenoid rings), urea and possibly 
also the ammonium chloride. The ammonium chloride 
may be used alone as the catalyst but the use of ammo- 
nium molybdate as well allows the reaction to proceed 
at a lower temperature and increases the yield. 
Nitrobenzene is an advantageous solvent because, 
besides being unreactive and being a good solvent for 
the reactants, it has a high boiling point (210" C). Other 
aprotic solvents such as quinoline and tetralin may be 
used. Yields of 90% or more are obtainable. 
The metal M may be removed from the molecule as 
by dissolving it in concentrated sulfuric acid to produce 
the hydrogen (protonated) species in which each of the 
two covalent bonds is connected to hydrogen. The 
protonated species may then be treated with an alco- 
holic solution of a metal salt, e.g., copper sulfate, to 
insert the metal, e.g., Cu(I1). In this way one metal may 
be substituted for another. However, it is preferred to 
choose the desired metal initially and to insert it in the 
phthalocyanine molecule in the synthesis of the tetra- 
carboxylic acid. 
EXAMPLE 4 
Polymerization of MPTC-Method 1 
About 1-2 g of metal phthalocyanine tetracarboxylic 
acid was finely ground in a small vibrating ball mill and 
placed in a polymerization tube. The tube was con- 
nected to an apparatus provided with a tube to con- 
dense volatile products, stopcocks to connect gas col- 
lection tube and IR cell for gaseous analysis. The appa- 
ratus was connected to vacuum system. Reaction tube 
was carefully evacuated to lO-5-lO-6ton pressure and 
heated to 450" C. The gaseous and volatile products 
were condensed in separate traps using liquid nitrogen. 
The reaction was found to be completed after one hour 
of heating at 450" C. in vacuum. 
, 
50 acid was -taken in a reaction tube fitted with a glass 
enclosed iron-constantan thermocouple and inlet and 
outlet tubes. The polymerization tube was carefully 
purged with nitrogen by repeated evacuation and refill- 
ing. Then it was gradually heated to 450" C. in a current 
55 of nitrogen and maintained temperature of 450"-500" C. 
in a current of nitrogen for one hour. 
Methods 1 and 2 were applied to produce the divalent 
copper, cobalt and nickel compounds. Analytical re- 
sults were the same for products of the two methods 
M) and were as follows: 
EXAMPLE 5 
Polymerization of MPTC-Method 2 
Finely ground metal phthalocyanine tetracarboxylic 
..
may be used provided the counter ion is compatible 
with the reactants and the reaction product. For exam- 
ple, the metal M may be used in the form of its sulfate, 
chloride, nitrate, acetate, oxalate, etc. Also, it may be 
used in the form of a finely divided metallic powder. 65 898w, 773w, 754w, 738s. 
Preferably the reactants are used in approximately stoi- 
chiometric proportions. The reactants are trimellitic 
anhydride 
(1) Compound C32H12NsCu: calcd: c, 67.18; H, 2.11; 
N, 19.58; CU, 11.2, found c, 66.9; H, 2.21; N, 19.8; CU, 
11.5. IR absorption bands (cm-1): 161Ow, 1503w, 
1407w, 1328m, 1271m, 1164m, 1118w, 1089m, 1065m, 
(2) Compound C ~ ~ H ~ Z N ~ C O :  calcd C, 67.73; H, 2.13; 
N, 19.75; Co, 10.39, found: c, 67.6; H, 2.3; N, 19.95; Co, 
10.46. IR absorption bands (cm-1): 1599w, 1502w, 
4,450,268 
5 6 
1408w, 1329m, 1292m, 11 15w, 1090m, 106ow, 94Ow, 
902w, 785w, 74Ow, 741s. 
looo" C. Char yields at 800" C. in nitrogen and electric 
conductivities are given in Table I. 
TABLE I 
CONDumTY (22-3ofJ- C.) 
CUPC-Sbeet 760 90.5% 3.2 x lb-10-3.8 x 
Polvmer 
C&CXheet 860 89.0% '1.8 x 10-8-2.3 x 10-3 
Polymer 
NipC-Sheet 890 93.0% 1.4 x 10-8-3.9 x 
Polymer 
(3) Compound C32H12NsNi: calcd: C, 67.76; H, 2.13; 
N, 19.75; Ni, 10.35, found: C, 67.8; H, 2.18; N, 19.92; Ni, 
10.43. IR absorption bands (cm-1): 1602w, 1519w, 15 
1409w, 1334m, 1287m, 1157m, 1115w, 1086m, 1053w, 
944w, 914w, 782w, 745w, 743m. 
The polymerization reaction proceeds by way of the 
elimination of carboxyl groups and the formation of a 
sheet polymer in which the mer units are linked by 2o 
biphenyl linkage. The formula of the polymer may be 
expressed as follows: 
I 
25 
30 
35 
40 
45 
In FIG. 3 of the drawing the results plotted are for 
Cu, Co and Ni sheet polymers heated in an atmosphere 
50 of nitrogen. The ordinate scale on the left represents 
percent decomposition and the ordinate scale on the 
right represents rate of weight loss. As will be seen the 
polymers did not undergo substantial decomposition 
below 750" C. to 800" C. (See curves at top.) The rate of 
55 decomposition (lower set of curves) did not become 
substantial until about 750' to 900" C. 
It will be apparent that purer metal phthalocyanine 
tetracarboxylic acids are provided, that a new and use- 
These polymers are soluble in concentrated (98%) ful method of preparing them has been provided and 
sulfuric acid, concentrated (36%) hydrochloric acid, 60 that new and useful polymers and methods of producing 
chlorosulfuric acid and trimethyl sulfonic acid. They them have been provided. 
have high thermal resistance and have a higher electri- It is claimed: 
cal conductivity (as well as a higher thermal oxidative 1. A method of preparing a heat stable and oxidation 
resistance) than the phthalocyanine monomers. Thresh- resistant sheet polymer of a metal phthdocyanine 
old temperatures at which major decomposition occurs 65 which comprises heating a metal 4,4',4",4'"-tetracar- 
are typically higher than 450" C. in air; they have a high boxylic phthalocyanine to a temperature sufficient to 
char yield in nitrogen and in nitrogen atmosphere no result in the formation of gaseous products and to form 
catastrophic decomposition has been observed up to a sheet polymer having the repeating structure 
M = Cu, Co, Nib.. . 
7 
I 
4,450,268 
8 
7. The method of claim 4 wherein M is Ni. 
8. A heat stable oxidation resistant sheet polymer 
having the repeating structure 
5 
10 
15 
20 
25 
30 
35 
I 
wherein M is a metal. 
2. The method of claim 1 wherein the heating is car- 
ried out under vacuum. 
3. The method of claim 1 wherein the heating is car- 4o 
ried out in an atmosphere of an inert gas. 
4. The method of claim 1 wherein the metal M is a 
divalent metal having an atomic radius of approxi- 
mately 1.35 A. 
wherein M is a metal, 
the metal is a 
divalent me@ having an atomic radius of approxi- 
mately 1-35 A. 
9. The polymer of claim 8 
10. The polymer of claim 9 wherein &.f is a. 
11. The polymer of claim 9 wherein M is Co. 
12. The polymer of claim 9 wherein M is Ni. 5. The method of claim 4 wherein M is Cu. 
6, The method of claim 4 wherein M i s  Co. 
45 * * * * *  
50 
55 
60 
65 


Metal phthalocyanine polymers

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