Polyphenylquinoxalines are prepared by the nucleophilic displacement reaction of di(hydroxyphenyl)quinoxaline monomers with activated aromatic dihalides or dinitro compounds. The reactions are carried out in polar aprotic solvents during alkali metal bases at elevated temperatures under nitrogen. The di(hydroxyphenyl)quinoxaline monomers are prepared either by reacting stoichiometric quantities of aromatic bis(o-diamines) with a hydroxybenzil or by reacting o-phenylenediamine with a dihydroxybenzil or bis(hydroxyphenylglyoxylyl)benzene

Connell, John W.

Hergenrother, Paul M.

Polyphenylquinoxalines are prepared by the nucleophilic displacement reaction of di(hydroxyphenyl)quinoxaline monomers with activated aromatic dihalides or dinitro compounds. The reactions are carried out in polar aprotic solvents using alkali metal bases at elevated temperatures under nitrogen. The di(hydroxyphenyl)quinoxaline monomers are prepared either by reacting stoichiometric quantities of aromatic bis(o-diamines) with a hydroxybenzil or by reacting o-phenylenediamine with a dihydroxybenzil or bis(hydroxyphenylglyoxylyl)benzene

NASA Technical Reports Server

United States Patent 
Hergenrother et al. 
[54] POLYPHENYLQUINOXALINES VIA 
AROMATIC NUCLEOPHILIC 
DISPLACEMENT 
[75] Inventors: Paul M. Hergenrother, Yorktown; 
John W. Connell, Newport News, 
both of Va. 
represented by the Administrator of 
the National Aeronautics and Space 
Administration, Washington, D.C. 
[73] Assignee: The United States of America BS 
[21] Appl. No.: 250,661 
[22] Filed: Sep. 28,1988 
[51] Int. c1.4 .............................................. C08G 73/06 
[52] U.S. c1. .................................... 528/125; 528/126; 
528/171; 528/172; 528/185 
[58] Field of Search ............... 528/126, 125, 171, 172, 
528/185 
~561 References Cited 
U.S. PATENT DOCUMENTS 
4,024,067 5/1977 Paciorek et al. .................... 528/229 
[ill Patent Number: 4,908,426 
[45] Date of Patent: Mar. 13, 1990 
. 4,375,536 3/1983 Hergenrother ..................... 528/229 
OTHER PUBLICATIONS 
Chemical Abstracts vol. 109, 1988-55338r. 
Primary Examiner-Harold D. Anderson 
Assistant Examiner-T. Mason 
Attorney, Agent, or Finn-George F. Helfrich; John R. 
Manning; Charles E. B. Glenn 
Polyphenylquinoxalines are prepared by the nucleo- 
philic displacement reaction of di(hydroxypheny1)- 
quinoxaline monomers with activated aromatic dihal- 
ides or dinitro compounds. The reactions are carried 
out in polar aprotic solvents using alkali metal bases at 
elevated temperatures under nitrogen. The di(hydroxy- 
pheny1)quinoxaline monomers are prepared either by 
reacting stoichiometric quantities of aromatic bis(o-dia- 
mines) with a Shydroxybenzil or by reacting o- 
phenylenediamine with a dihydroxybenzil or bis(hy- 
droxyphenylglyoxyly1)benzene. 
1571 ABSTRACT 
12 Claims, No Drawings 
https://ntrs.nasa.gov/search.jsp?R=20080008785 2019-08-30T03:43:23+00:00Z
4,908,426 
1 2 
Second, the bis(pheny1-a-diketones) required for 
polyphenylquinoxaline formation are relatively difficult 
Third, the structure of polyphenylquinoxaline is diffi- 
Thus, it is an object of this invention to prepare con- 
POLYPHENYLQUINOXALINES VIA AROMATIC 
NUCLEOPHILIC.DISPLACEMENT to prepare and expensive. 
ORIGIN OF INVENTION 5 culttovary. 
The invention described herein was made by employ- 
e= of the United States Government and may be manu- figurationally ordered polyphenylquinoxalines, in Order 
facured and used by or for the Government for govern- to improve strength and resistance to attack by Organic 
mental purposes without payment of any royalties 
thereon or therefor. 
BACKGROUND OF INVENTION 
10 It is a further object to devise a means of preparing 
polyphenylquinoxaline, either configurationally or- 
dered or not, by a means other than the bis(pheny1-a- 
diketone)/bis(o-diamine)condensation, so that the use of 
expensive bis(pheny1-a-diketones) may be avoided and 
more readily and 
polyphenylquinox~es are high ther- 
moplastics which excellent as ad- 
materials are heterocyclic polymers synthesized by the 
condensation reaction of a bis(pheny1-adketone) with 
an aromatic bis(o-diamine). 
h=iv=, coatings, fh and composite matrices. These ' 5  so that the @YPhenYhuinoxaline structure can be varied* 
SUMMARY OF INVENTION 
Schematically, this m y  be represented in Equation 1: The objects of this invention are &tained by (l) 
20 forming di(hydroxypheny1)quinoxaline monomers (a) 
by the condensation of 2 moles of a hydroxybenzil with 
an aromatic bis(o-diamine) as represented in Equation 
25 Eq. I1 
solvent 
30 solvent 
- 1 \N, 
N 
OH Polyphenylquinoxalines prepared from such conden- sations are configurationally unordered with three pos- 40 
sible isomers distributed randomly along the polymer 
chain; see Hergenrother, Encyclopedia of Polymer Sci- 
ence Technology, Vol. 13, p. 55, (1988). where Ar is 1,2,4,5-tetrasubstituted benzene, 3,3',4,4'- 
As a direct result of the use ofthe condensation reac- tetrasubstituted; biphenyl, diphenylether, diphenyl- 
tion to synthesize polyphenylquinoxalines, there are 45 methane, diphenyllcetone, diphenylsulfone, diphenyl- 
several limitations. thioether or any appropriate bis(o-diamine) and mix- 
First, becam the polyphenylquinOx&es are not tures thereof. The catenation of the hydroxy group may 
configurationally ordered, their mechanical properties be meta-me@ para-para, or para-meta. 
(as evidenced for example by tensile modulus) and Alternatively, the di(hydroxypheny1) quinoxaline 
strength are limited, and the resultant lack of crystallin- 50 monomers are formed (b) by the condensation of a 
ity renders them subject to attack by chlorinated or- dihydroxybenzil with an aromatic 0-diamine, which 
ganic solvents. may be a substituted o-diamine, as represented in Eqda- 
tion 111: 
HO 
solvent 
4,908,426 
3 
-continued 
N N 
4 
where Z=H, C1, Br, OCH3, CH3, CH2CH3, or Ph. The 
catenation of the hydroxy group may be meta-meta, 0 0 0 0 
para-para, or para-meta. II 
ducing correspondingly more complex phenylquinoxa- 
More complex dihydroxybenzils may be used, pro- 2o 
-C 
\line monomers, as represented in Equation IV: 
HofqppoH. 
@ @ Z N N 
Z 
and where.Y is F, C1, or N02. 
The polyphenylquinoxaline synthesis and product 
structure may be represented below, in its two main 
In the case where Z is H, there are no configurational 55 variants: 
isomers. 
(2) Polyphenylquinoxaliies are produced by the aro- 
matic nucleophilic displacement reaction of a phenyl 
quinoxaliue monomer (described above) with an acti- 
vated aromatic compound of the following structure: 
Eq. " 
y-@x-@l-y + H O G A r Q - O H  
a. 
alkali metal base I solvent 
where X is selected from the group in Equations V and 
VI: where Ar is: 
5 
4,908,426 
6 
b. 
N N N  N N N N  N N N 
Z' z 
Y DXTQLy+ HO 3N 
N 
N 
N 
0 go;, 
-continued 
where 0 0 
Y R is F, nil, C1, SOz, or NOz, C , 0, S, C(CH3)z, C(CF3)z, or CHz -!Q@"-. 
0 0 0 -!Q@ 0 0 
0 II -!ocH20!!- 0 and, 
and 45 
X is: C=O, SOz, 
II -!o!-, -C QrC- 50 
55 6, -!B!-, -!-!-; 0 
60 
and wherein n is an integer between 4 and 100. 
Where the di(hydroxypheny1)quinoxaline monomers 
65 have structural isomers, the resultant polyphenyl- 
quinoxaline is not configurationally ordered, but the 
polyphenylquinoxalines are new and have excellent 
properties. 
0 
7 
4,908,426 
8 
Where the di(hydroxypheny1)quinoxaline monomers 
have no structural isomers, the resultant polyphenyl- 
quinoxaline is configurationally ordered; certain of 
these polyphenylquinoxalines are semi-crystalline. 
The ConfitWationallY ordered POlYPhenYlquinOXa- 
hes  are insoluble in polar aprotic Solvents such as N,N- 
dimethylacetamide, N-methylpyrrolidone, and dimeth- phenylquinoxaline where is F, is 
ylsulfoxide, and are insoluble in chlorinated hydrocar- 
bons such as methylene chloride, chloroform and tetra- 
chloroethane. Thin films of representative conftgura- 10 
tionally ordered polyphenylquhoxalines were im- 
mersed in hydraulic fluid for 24 hours and chloroform 
crazing was observed. 
177" C. of 6550 psi, 250,000 psi and 65 percent respec- 
tively. 
EXAMPLE 2 
The following Example illustrated the reaction se- 
quence for the synthesis of a semi-crystallhe poly- 
for one hour, after which no noticeable swelling or -C 
15 
DETAILED DESCRIPTION OF INVENTION 
Having generally described the invention, a more 
complete understanding thereof can be obtained by 
reference to the following specific examples which are 
not limit the invention. 
and Ar is 
N provided herein for purposes of illustration only and do 2o N 
EXAMPLES 
EXAMPLE 1 
25 . 
The following Example illustrates the reaction se- 
quence for the synthesis of the polyphenylquinoxaliie Z 
where Y =F, R = d  and X is: 
and Z is H. See Equation V. 
0 30 Monomer Synthesis-2,3-bis(Chydroxyphenyl)- 
quinoxaline: Into a 250 ml round bottom flask equipped 
with a magnetic stirrer and reflux condenser was placed 
1,2-diaminobenzene (2.3275 g, 0.0215 mol), 4,4'-dihy- 
droxybenzil(5.2135 g, 0.0215 mol) and absolute ethanol 
35 (30 ml). The solution was stirred for one-half hour at See Equation VI. 
Monomer room temperature, and a Yellow Precipitate formed. 
phenylquinoxaline] and isomers: Into a 250 ml round . The mixture Was heated to reflux overnight. The Sol- 
bottom flask quipped with a magnetic strirrer and vent was removed by vacuum distillation and the solid 
reflux condenser was placed Chydroxybenzil (6.23 g, 4o dried at loo" C. for two hours to give 6.6 g (97%) of 
0.0274 mol), 3,3'-diaminobenzidine (2.94 g, 0.0137 mol), yellow powder. The material was recrystallized from 
absolute ethanol (30 ml) and benzene (30 ml). The mix- 1,4-dioxane/water mixture. Yield 6.0 g (89%) m.p. 336" 
ture was stirred at room temperature for one hour, then C.-338' C. Anal. Calcd for C20H14N202: C, 76.42%; H, 
refluxed Overnight- The was and the 4.49%, N, 8.91%. Found C, 76.54%; H, 4.44%; 
yellow solid was filtered, washed with water and dried 45 N,8.96%. 
at loo" c. for three hours. 7.94 g (98%), m*p* 
> 3 w  c. Anal. Calcd. for C40H26N402: c, 80.79%; H, 
4.41%; N, 9.42%. Found C, 80.56%; H, 4.22%; N, 
9.48%. 
Polyphenylquino*e SynthesiS-Into a 100 ml three 
neck round bottom flask equipped with a mechanical 
PO1ypheny1quho-e Systhesis-Into a 250 ml three 50 reflux condenser was placed l,Cbis(CfluorobenxoYl)- 
stirrer, thermometer, nitrogen inlet, moisture trap and 
neck round bottom flask equipped with a mechanical benzene (1.4604 g, 0.0045 mol), 2,3-bis(Chydroxy- 
stirrer, thermometer, nitrogen inlet, moisture trap, and PhenYl)quino&e (1.4243 g, 0.0045 mol), powdered 
reflux condenser was placed 1,3-bis(Cfluorobenzoyl)- anhydrous potassium carbonate (1.45 g, 0.0104 mol), 
benzene (1.9339 g, 0.006 mol), 6,6'-bis[2-(Chydroxy- N,N-dimethylacetamide (19 ml) and toluene (20 ml). 
phenyl)-3-phenylquinoxaline] and isomers (3.5678 g, 55 The mixture was heated to 135' C. for three hours to 
0.006 mol) powdered anhydrous pomium carbonate remove water, then increased to 155" C. overnight. The 
(1.90 g, 0.0138 mol), N,N-dimethYlacetamide (4 ml) polymer had precipitated from solution overnight dur- 
and toluene (25 ml). The mixture was heated to 135" C. ing the synthesis. ne mixture was poured into acetic 
for three to four hours to remove water, toluene was acid/water to give a white powder was subse- 
increased to 155' C. overnight. The polymer was iso- 
lated by precipitation into water/acetic acid mixture, dried at loo" C. Yield 2.6 g (97%) of white polymer 
washed success~ve~y with water and methanol and with a glass transition temperature of 208' C. and a 
dried. Yield 5.1 g (97%) of off-white polymer with an crystalline melt temperature of 365" C. The inherent 
inherent viscosity of 1.09 dL/g and a glass transition 65 ViSCOSitY of a 0.5 Percent solution in m-cresol measured 
temperature of 240" C. Thin films cast from m-cresol at 25" C. was 0.83 dL/g. A thin film cast from m-cresol 
solution gave tensile strength, tensile modulus and elon- was determined to be semi-crystalline by wide angle 
gation at 25" C. of 11,500 psi, 35,000 psi and 7.7% and at X-ray diffraction. 
removed from the and the temperature was 60 quently washed with water and then and 
4,908,426 
10 9' 
ture was diluted with absolute ethanol (125 ml) and 
refluxed overnight. The mixture was poured into water, 
collected and dried to give 7.0 g (98%) of yellow solid. 
The solid was recrystallized from ethanol/water (5:l) 
5 mixture to give yellow neddles, m.p. 339" C.-343" C. 
Polyphenylquinoxaline Synthesis-Into a 100 ml three 
neck round bottom flask equipped with a mechanical 
stirrer, thermometer, nitrogen inlet, moisture trap and 
reflux condenser was placed 4,4'-diiluorodiphenyl sul- 
10 fone (1.2712 g, 0.005 mol), 1.3-bis[2-quinoxalyl-3-(4- 
hydroxyphenyl)]benzene (2.5927 g, 0.005 mol), pow- 
dered anhydrous potassium carbonate (1.6 g, 0.0115 
EXAMPLE 3 
The following Example illustrates the reaction se- 
quence for the synthesis of a semi-crystalline poly- 
phenylquinoxaline where Y is F, X is S O 2  and Ar is 
N N N N 
15 
20 See Equation V. Monomer Synthesis-l,3-bis[2-quinoxalyl-3-(4- 
hydroxy-pheny1)lbenzene. Into a 250 ml round bottom 
flask equipped with a magnetic stirrer and reflux con- 
denser was placed 1,3-bis(4-hydroxyphenylglyoxylyl)- 
benzene (5.1412 g, 0.0137 mol), 1,2-diaminobenzene 25 
(2.9705 g, 0.0274 mol) and absolute ethanol (45 ml). The 
mol), N,N&nethylacetamide (20 ml) and toluene (35 
ml). The mixture was heated to 135" C. for three to four 
hours to remove water, then increased to 155" C. over- 
night. The polymer had precipitated from solution 
overnight during the synthesis. The mixture was poured 
into acetic acid/water to give an off-white powder 
which was subsequently washed with water and then 
methanol and dried at loo" C. Yield 3.55 g (99%) of 
polymer with a glass transition temperature of 235" C. 
and a crystalline melt temperature of 388" C. The inher- 
ent viscosity of a 0.5 percent solution in m-cresol mea- 
sured at 25" C. was 0.24 dL/g. 
Polymer characterization is presented in Tables 1 and 
2 below. 
TABLE 1 
POLYMER CHARACTERIZATION 
R X 9inh. dl/g* Tg, T.** 
nil so2 0.90 283 
nil co 0.80 252 
nil isophthaloyl 1.09 240 
co so2 0.69 268 
co co 1.30 253 
. 255 
235 
co terephthaloyl 1.01 
co isophthaloyl 0.61 
0 so2 0.34 240 
0 terephthaloyl 0.45 226 
0 isophthaloyl 0.46 213 
*Inherent viscoSities in  cresol at 0.5% concentration (w/v) at 25' C. 
**Determined by ditlcrmtial sovlning calonmctry at 20' C./min. 
solids dissolved rapidly to give an orange solution, and 
after 15 minutes a yellow precipitate formed. The mix- 
TABLE 2 
POLYMER CHARACTERIZATION 
7 O Q  0 polQlxa 
N 
f i  
N 
llinh dL/g* Tg, T.** 
0.54 240 
0.58 209 
X 
so2 co 
4,908,426 
. 11 12 
TABLE 2-continued 
POLYMER CHARACTERIZATION 
T q p 0 Q X G  
N N 
X ninh dL/n* Ta. T.** 
0 -yQp C- 0.83 208(Tm = 365) 
0.50 179 0 -w - 
0 oo lQrxa  4 w N N 
43 
co 0.52 179(Tm = 377) 
0 0 ooQxJQf 
N N N N 
so2 0.24 235(Tm = 388) 
*Inherent viscosities in m-craol at 0.5% concentration (w/v) at 25' C. 
**Determined by differential scanning calorimetry at 20' C./min. 
What is claimed as new and desired to be secured by 
Letters Patent of the United States is: 
~ 1. A poly(pheny1quinoxaline) consisting of repeating 
units having the general structural formula 
60 
wherein the substitution of oxygen is selected from the 
65 group consisting of meta-meta, para-para, and para- 
j & x ~ o ~ A r 4 3 +  f 
mew wherein Ar is a radical selected from the group con- 
sisting of: 
13 
4,908,426 
wherein R is a bond or is selected from the group 
consisting of: 
0, S, c--O, SO29 CH2, C(CH3)2, and C(CR)Z; 10 
N 
H 
N 
Z @' 
N N N  N 
@' @ ' m d  
2 2 
N N '  N N 
20 
(C) 
25 
14 
-continued 
0 
30 and wherein n is an integer between 4 and 100. 
2. The poly(pheny1quinoxaline) of claim 1 wherein 
Ar is a radical represented by: 
and R is a bond or is selected from the group consisting 
4o of: 
0, and 0. 
3. The poly(pheny1quinoxaline) of claim 2 wherein X 
is selected from the group consisting of: 
45 S02,C=O,and 
2 2 -!Q!-, 0 0 Q!-. 0 
wherein Z is a substituent selected from the group 
consisting of: H, F, C1, Br, CH3, CH2CH3, OCH3, 50 
CsHs and C6H50; 
sisting of: 
0 0 0 0 
-C 
wherein X is a radical selected from the group con- 
4. The polymer of claim 1 wherein Ar is represented 
by: 
55 
II 
N 
H 
N 
0 
II 
6 
0 0 
II 
C--, -8 
60 
65 
z .  @ 
and X is selected from the group consisting of ,902, 
0, and 
15 
4,908,426 
16 
-continued 
5. The polymer of claim 4 wherein Z is H. 
6. The poly(pheny1quinoxaline) of claim 1 wherein 10 
Ar is represented by: 
Z Z 
N N N N 
20 N N N N 
Z Z @ @  25 Z Z 
and X is SOz. wherein Z is a substituent selected from the group 
H9 F, ck Br, CH3, CHZCH3, ocH3, C6H5, and 
with an activated aromatic dihalide or dinitro com- 
7. The polymer of claim 6 wherein Z is H. 
8. A process for synthesizing polyphenylquinoxliies 30 
consisting of: 
c 6 I 5 0 ;  by aromatic nucleophilic displacement, which com- 
reacting a ~(hydroxyPheny1)quinodine having Domd havina the aeneral structure: 
the general structure: 
- -  
35 
40 
wherein X is a radical selected from the group con- 
sisting of: wherein Ar is a radical selected from the group con- 
sisting of: 
45 
wherein R is a bond or is selected from the group 
0, S, c---O, SO2, CHz, C(CH3)2, and C(CF3)2; 
consisting of: 
55 
0 0 0 0 
c, II SOZ, -!@ 
0 
II 
6 
0 0 
II 
C-9 -8 
N N 
Z @’ 
17 
-continued -!Q0O!-, 0 0 
-!acH20!- 0 and, 
-?Q@-; 0 0 
18 
4,908,426 
_ _  
N-cyclohexylpyrrolidinone, and dimethylsulfox- 
ide; 
wherein said reaction is carried out in the presence of 
an alkali metal base selected from the group con- 
sisting of KzCO3, NazC03, KOH, and NaOH; and 
wherein said reaction is carried out with the applica- 
tion of heat. 
9. The method of claim 8 wherein X is selected from 
5 
the group consisting of: SOz, CLO, and 
10 
10. The method of claim 8 wherein Y is is selected 
from the group consisting of F and C1. 
wherein Y is selected from the group consisting of: 
C1, F, and NOz, and wherein said reaction k car- 20 the group consisting of F and ~ 1 .  
ried out in a polar aprotic solvent selected from the 
group consisting of N,N-dimethylacetamide, N- 
methylpyrrolidinone, sulfolane, diphenylsulfolane, * * * * *  
11. The procesi of claim 9 wherein y is selected from 
12. The method of claim 8 where the solvent is N,N- 
dimethylacetamide. 
25 
30 
35 
40 
45 
50 
55 
60 
65 


Polyphenylquinoxalines via aromatic nucleophilic displacement

United States Patent [191 [ i l l  Patent Number: 5,010,197 
Hergenrother et al. [45] Date of Patent: Apr. 23, 1991 
POLYPHENYLQUINOXALINES VIA 
AROMATIC NUCLEOPHILIC 
DISPLACEMENT 
Inventors: Paul M. Hergenrother, Yorktown; 
John W. Connell, Newport News, 
both of Va. 
Assignee: The United States of America as 
represented by the Administrator of 
the National Aeronautics ind Space 
Administration, Washington, D.C. 
Appl. NO.: 454,820 
Filed: Dec. 22, 1989 
Related U.S. Application Data 
Division of Ser. No. 250,661, Sep. 28, 1988, abandoned. 
Int. Cl.5 ....................... C08G 8/02; C07D 241/36 
U.S. CI. .................................... 544/353; 528/125; 
528/126; 528/171; 528/172; 528/185 
Field of Search ................ 544/353; 528/125, 126, 
528/171, 172, 185 
[5 61 References Cited 
U.S. PATENT DOCUMENTS 
3,852,244 12/1974 Heath et al. ........................ 528/125 
3,966,729 6/1976 Kovar et al. ........................ 528/125 
4,739,058 4/1988 Fekhardt et al. ................... 544/353 
Primary Examiner-John Kight, I11 
Assistant Examiner-T. Mosley 
Attorney, Agent, or Firm-George F. Helfrich; Harold 
W. Adams; John R. Manning 
[571 ABSTRACT 
Polyphenylquinoxalines are prepared by the nucleo- 
philic displacement reaction of di(hydroxypheny1)- 
quinoxaline monomers with activated aromatic dihal- 
ides or dinitro compounds. The reactions are carried 
out in polar aprotic solvents during alkali metal bases at 
elevated temperatures under nitrogen. The di(hydroxy- 
pheny1)quinoxaline monomers are prepared either by 
reacting stoichiometric quantities of aromatic bis(o-dia- 
mines) with a hydroxybenzil or by reacting o- 
phenylenediamine with a dihydroxybenzil or bis(hy- 
droxyphenylglyoxyly1)benzene. 
3 Claims, No Drawings 
https://ntrs.nasa.gov/search.jsp?R=20080008276 2019-08-30T03:34:45+00:00Z
5,010,197 
1 2 
dered or not, by a means other than the bis(pheny1-a- 
diketone)/bis(o-diamine) condensation, so that the use 
. NUCLEOPHILIC DISPLACEMENT of expensive bis(pheny1-a-diketones) may be avoided 
and so that the polyphenylquinoxaline structure can be 
SUMMARY OF INVENTION 
POLYPHENYLQUINOXALINES VIA AROMATIC 
This is a division of application Ser. No. 07/250,661, 5 readily and conveniently varied. 
filed Sept. 28, 1988 now abandoned. 
ORIGIN OF INVENTION 
The objects of this invention are obtained by (1) 
by the condensation of 2 moles of a hydroxybenzil with 
an aromatic bis(o-diamine) as represented in Equation 
The invention described herein was made by employ- 
and used by or for the G~~~~~~~~ for governmental 
purposes without payment of any royalties thereon or 
BACKGROUND OF INVENTION 
Polyphenylquinoxalines are high temperature ther- 
mo-plastics which exhibit excellent performance as 
These materials are heterocyclic polymers synthesized 
by the condensation reaction of a bis(pheny1-a-dike- 20 
tone) with an aromatic bis(o-diamine). 
Schematically, this may be represented in Equation I: 
ees of the U.S. Government and may be manufactured 10 forming di(hydroxyphenyl)quinoxaline (a) 
therefor. 11: 
15 Eq. I1 
H2N NHz 
\ /  
NH2 
adhesives, coatings, films and composite matrices. /Ar\ 
H2N 
solvent 
NH2 
\ /  
H2N 
. .  
Ar 
H2N NH2 
/ \  
0 0  0 0  
C-C-Ar'-C-C 
solvent I 
25 
30 HO 
N N  
\ /  
Ar 
/ \  
N N  
OH 
3/ where Ar is 1,2,4,5-tetrasubstituted benzene, 3,3',- 4,4'- 
35 tetrasubstituted; biphenyl, diphenylether, diphenyl- 
methane, diphenylketone, diphenylsulfone, diphenyl- 
thioether or any appropriate bis(o-diamine) and mix- 
tures thereof. The catenation of the hydroxy group may p$N\A."o - / \  4 4" 40 be Alternatively, meta-meta, para-para, the di(hydroxypheny1) or para-meta. quinoxaline 
monomers are formed (b) by the condensation of a 
dihydroxybenzil with an aromatic o-diamine, which 
may be a substituted o-diamine, as represented in Equa- 
tion 111: 
0 N N  0 
Polyphenylquinoxalines prepared from such conden- 
sations are configurationally unordered with three pos- 45 
sible isomers distributed randomly along the polymer 
chain; see Hergenrother, Encyclopedia of Pohmer Sci- 
ence Technology, Vol. 13, p. 55, (1988). 
As a direct result of the use of the condensation reac- 
Eq 111 
HOQ! +H2Nm 
c-c 
tion to synthesize polyphenylquinoxalines, there are 50 H2N Z 
several limitations. 
First, because the polyphenylquinoxalines are not 
configurationally ordered, their mechanical properties 
(as evidenced for example by tensile modulus) and 
strength are limited, and the resultant lack of crystallin- 55 
ity renders them subject to attack by chlorinated or- 
ganic solvents. 
Second, the bis(pheny1-a-diketones) required for 
polyphenylquinoxaline formation are relatively difficult 
PF How@oH to prepare and expensive. 60 
Third, the structure of polyphenylquinoxaline is diffi- N N 
cult to vary. 
Thus, it is an object of this invention to prepare con- 
figurationally ordered polyphenylquinoxalines, in order 
to improve strength and resistance to attack by organic 65 
solvents. 
It is a further object to devise a means of preparing 
polyphenylquinoxaline, either configurationally or- 
5,O 10,197 
3 4 
where Z = H ,  C1, Br, OCH3, CH3, CH2CH3, or Ph. The 
catenation of the hydroxy group may be meta-meta, 
para-para, or para-meta. 
More complex dihydroxybenzils may be used, pro- 
ducing correspondingly more complex phenylquinoxa- 5 
line monomers, as represented in Equation IV: 
and where Y is F, C1, or N02. 
The polyphenylquinoxaline synthesis and product 
structure may be represented below, in its two main 
variants: 
Eq. V 
quinoxaline monomer (described above) with an acti- 
vated aromatic compound of the following structure: 
40 
alkali metal base 
solvent 
heat 
where X is selected from the group in Equations V and 
VI: where 
Ar  is: 
N 
H 
N 
z @ 
N N N N N N N N 
z Z z Z 
5 
5,010,197 
6 
solvent 
alkali metal base 
EXAMPLES 
30 Example 1 
where: The following Example illustrates the reaction se- 
quence for the synthesis of the polyphenylquinoxaline 
where Y=F,  R=nil and X is: 
Y is F, C1, or NO2, 
R is nil, S02, CO, 0, S ,  C(CH3)2, C(CF3)2, or CH2 
and 
0 X is: C=O, S02, 3s -!ai-. 0 -C o!- 0 0 40 -mi- 
See Equation VI. 
Monomer Synthesis Where the di(hydroxypheny1)quinoxaline monomers 
have structural isomers, the resultant polyphenyl- 6,6'-bis[2-(4-hydroxyphenyl)-3-phenylquinoxaline] 
quinoxaline is not configurationally ordered, but the 45 and isomers: Into a 250 ml round bottom flask equipped 
polyphenyl-quinoxalines are new and have excellent with a magnetic stirrer and reflux condenser was placed 
properties. 4-hydroxybenzil (6.23 g, 0.0274 mol), 3,3'-diaminoben- 
Where the di (hydroxypheny1)quinoxaline monomers zidine (2.94 g, 0.0137 mol), absolute ethanol (30 ml) and 
have no structural isomers, the resultant polyphenyl- benzene (30 ml). The mixture was stirred at room tem- 
quinoxaline is configurationally ordered; certain of 50 perature for one hour, then refluxed overnight. The 
these polyphenyl-quinoxalines are semi-crystalline. solution was cooled and the yellow solid was filtered, 
The configurationally ordered polyphenylquinoxa- washed with water and dried at 100" C. for three hours. 
lines are insoluble in polar aprotic solvents such as N,N- Yield 7.94 g (98%), m.p. > 360" C. Anal. Calcd. for 
dimethylacetamide, N-methylpyrrolidone, and dimeth- Cd-hjN402: C, 80.79%; H, 4.41 %; N, 9.42%. Found: 
ylsulfoxide, and are insoluble in chlorinated hydrocar- 55 C, 80.56%; H, 4.22%; N, 9.48%. 
bons such as methylene chloride, chloroform and tetra- 
chloroethane. Thin films of representative configura- 
tionally ordered polyphenylquinoxalines were im- 
mersed in hydraulic fluid for 24 hours and chloroform 
for one hour, after which no noticeable swelling or 60 
crazing was observed. 
DETAILED DESCRIPTION OF INVENTION 
Having generally described the invention, a more 
complete understanding thereof can be obtained by 65 
reference to the following specific examples which are 
provided herein for purposes of illustration only and do 
not limit the invention. 
t 
Polyphenylquinoxaline Synthesis 
Into a 250 ml three neck round bottom flask equipped 
with a mechanical stirrer, thermometer, nitrogen inlet, 
moisture trap, and reflux condenser was placed 1,3- 
bis(4-fluorobenzoy1)benzene (1.9339 g, 0.006 mol), 6,6'- 
bis[2-(4-hydroxyphenyl)-3-phenylquinoxaline] and iso- 
mers (3.5678 g, 0.006 mol) powdered anhydrous potas- 
sium carbonate (1.90 g, 0.0138 mol), N,N-dime- 
thylacetamide (40 ml) and toluene (25 ml). The mixture 
was heated to 135" C. for three to four hours to remove 
water, toluene was removed from the system and the 
temperature was increased to 155" C. overnight. The 
5,010,197 
7 8 
polymer was isolated by precipitation into watedacetic was subsequently washed with water and then metha- 
acid mixture, washed successively with water and nol and dried at 100" C .  Yield 2.6 g (97%) of white 
methanol and dried. Yield 5.1 g (97%) of off-white polymer with a glass transition temperature of 208" C .  
polymer with an inherent viscosity of 1.09 dL/g and a and a crystalline melt temperature of 365" C. The inher- 
glass transition temperature of 240" C. Thin films cast ent viscosity of a 0.5 percent solution in m-cresol mea- 
from m-cresol solution gave tensile strength, tensile sured at 25" C. was 0.83 dL/g. A thin film cast from 
modulus and elongation at 25" C. of 11,500 psi, 353,000 m-cresol was determined to be semi-crystalline by wide 
psi and 7.7% and at 177" C. of 6550 psi, 250,000 psi and angle X-ray diffraction. 
65 percent respectively. 
Example 2 
The following Example illustrates the reaction se- 
quence for the synthesis Of a Semi-crystalhe Poly- 
phenylquinoxaline where Y is F, X is 
10 Example 3 
The following Example illustrates the reaction se- 
quence for the synthesis of a semi-crystalline poly- 
phenylquinoxaline where y is F, X is SOz and Ar is 
15 
0 
and 
Ar is 
N N N N 
25 
N N See Equation V. 
30 Monomer Synthesis 
1,3-bis[2-quinoxalyl-3-(4-hydroxy-phenyl)]benzene. 
Into a 250 ml round bottom flask equipped with a mag- 
netic stirrer and reflux condenser was placed 1,3-bis(4- 
35 hydroxyphenylglyoxy1yl)benzene (5.1412 g, 0.0137 
mol), 1,2-diaminobenzene (2.9705 g, 0.0274 mol) and 
absolute ethanol (45 ml). The solids dissolved rapidly to 
give an orange solution, and after 15 minutes a yellow 
2,3~bis(4-hydroxyphenyl)quinoxaline~ I to a 250 ml 4o precipitate formed. The mixture was diluted with abso- 
lute ethanol (125 ml) and refluxed overnight. The mix- 
ture was poured into water. collected and dried to give 
Z 
and Z is H. See Equation V. 
Monomer Synthesis 
round bottom flask equipped with a magnetic stirrer 
and reflux condenser was placed 1,2-diaminobenzene 
was stirred for one-half hour at room temperature, and 45 dles~ m.p. 339" c.-3430 '. 
a yellow precipitate formed. The mixture was heated to Polyphenylquinoxaline Synthesis 
reflux overnight. The solvent was removed by vacuum 
distillation and the solid dried at 100" c. for two hours Into a 100 ml three neck round bottom flask equipped 
to give 6.6 (97%) of yellow powder. The material was with a mechanical stirrer, thermometer, nitrogen inlet, 
6.0 (89%) m.p. 336O c.-338" c, Anal. Calcd for difluorodiphenyl sulfone (1.2712 €5 0.005 mol), 1,3- 
CzoH14Nz02: C, 76.42%; H, 4.49%; N, 8.91%. Found: bis[2-quinoxaiyl-3-(4-hydroxyphenyl)] benzene (2.5927 
C, 76.54%; H, 4.44%; N,8.96%. g, 0.005 mol), powdered anhydrous potassium carbon- 
ate (1.6 g, 0.01 15 mol), N,N-dimethylacetamide (20 ml) 
Polyphenylquinoxaline Synthesis 55 and toluene (35 ml). The mixture was heated to 135" C. 
Into a 100 ml three neck round bottom flask equipped for three to four hours to remove water, then increased 
with a mechanical stirrer, thermometer, nitrogen inlet, to 155" C. overnight. The polymer had precipitated 
moisture trap and reflux condenser was placed 1,4-bis(4- from solution overnight during the synthesis. The mix- 
fluorobenzoy1)benzene (1.4604 g, 0.0045 mol), 2,3-bis(4- & ture was poured into acetic acid/water to give an off- 
hydroxypheny1)quinoxaline (1.4243 g, 0.0045 mol), white powder which was subsequently washed with 
powdered anhydrous potassium carbonate (1.45 g, water and then methanol and dried at 100" C. Yield 3.55 
0.0104 mol), N,N-dimethylacetamide (19 ml) and tolu- g (99%) of polymer with a glass transition temperature 
ene (20 ml). The mixture was heated to 135" C. for three of 235" C. and a crystalline melt temperature of 388" C. 
hours to remove water, then increased to 155" C. over- 6 5  The inherent viscosity of a 0.5 percent solution in m- 
night. The polymer had precipitated from solution cresol measured at 25" C. was 0.24 dL/g. 
overnight during the synthesis. The mixture was poured Polymer characterization is presented in Tables 1 and 
into acetic acid/water to give a white powder which 2 below. 
(2.3275 g, 0.0215 mol), 4,4'-dihydroxybenzil (5.2135 g, 
0.0215 mol) and absolute ethanol (30 ml). The solution 
7.0 g (98%) Of yellow 
from 
The was 
(5:1) mixture to give yellow nee- 
recrystallized from 1,4-dioxane/water mixture. Yield 50 moisture trap and reflux condenser was placed 494'- 
5,010,197 
9 10 
TABLE 1 
POLYMER CHARACTERIZATION 
R X T i n h d L / g *  Tg, T." 
0.90 283 
0.80 252 
nil so2 
nil co 
nil isophthaloyl 1.09 240 
co so2 0.69 268 
253 co co 1.30 
co terephthaloyl 1.01 255 
co isophthaloyl 0.61 235 
226 0 terephthaloyl 0.45 
0 isophthaloyl 0.46 213 
0 so2 0.34 240 
'Inherent vicosities in m-cresol at 0.5% concentration (w/v) at 25' C. 
"Determined by differential scanning calorimetry at 20' C./min. 
TABLE 2 
POLYMER CHARACTERIZATION 
X T i n h  dL/g' Tg, "C." 
N N 
0.54 
0.58 
3 3 2  co 
0 -Qp C- 
0 
-%I+- 
0.83 
0.50 
240 
209 
208 (Tm = 365) 
179 
co 0.52 179 (Tm = 377) 
11 
5,010,197 
12 
TABLE 2-continued 
POLYMER CHARACTERIZATION 
X r l inh dL/g* Tg, "C." 
N N N N 
so2 0.24 235 (Tm = 388) 
'Inherent viscosities in ~ s r e s o l  at 0.5% concentration (w/v) at 25' C. 
'*Determined by differential scanning calorimetry at 20" U r n i n .  
-continued 20 
25 
30 
35 
40 
What is claimed as new and desired to be secured by 
1. A di(hydroxypheny1)quinoxaline having the gen- 
Letters Patent of the U.S. is: 
eral structure: 
45 
N N N 
N A N N 
@ Z @* z 
wherein 
Z is a substituent selected from the group consisting 
of: H,F, Cl, Br, CH3, CH2CH3, OCH3, C&, and 
C6H50. 50 
wherein 2. The quinoxaline of claim 1 wherein Ar is: 
Ar is a radical selected from the group consisting of: 
H 
N N, 
60 
N N 
Z P 
3. The quinoxaline of claim 2 where Z is H. 
6 5  * * * * *  z' 


Polyphenylquinoxalines via aromatic nucleophilic displacement

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server

NASA Technical Reports Server