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29 Free Radical Copolymerization of 4,7-Dihydro1,3-dioxepins with Maleic Anhydride and Maleimides: Preparation of Head-to-Head Poly(4-hydroxycrotonic acid) and Poly(γ-crotonolactone) 1

Downloaded by UNIV OF CINCINNATI on May 30, 2016 | http://pubs.acs.org Publication Date: August 12, 1982 | doi: 10.1021/bk-1982-0195.ch029

B. M. CULBERTSON and A. E. AULABAUGH Ashland Chemical Company, Columbus, OH 43216

Acting as electron donor monomers, 4,7-dihydro– 1,3-dioxepins undergo free-radical initiated copoly merization with maleic anhydride (MA) to give good yields of low to moderate molecular weight, 1:1 alter nating copolymers. Under similar conditions, the same 1,3-dioxepins copolymerize in a nonequimolar fashion with maleimides to give good yields of sol uble copolymers. Total hydrolysis of the anhydride copolymers produce previously unreported head-to -head poly (4-hydroxycrotonic acid). The hydrolyzed copolymers readily cyclize to previously unreported head-to-head poly (γ-crotonolactone). In the pres ence of strong acids the 1,3-dioxepin-alt-MA copoly mers rearrange to poly (γ-crotonolactone)· At ele vated temperatures (>200°C), the anhydride copolymers also thermally rearrange to poly (γ-crotonolactone), eliminating aldehyde or ketone. The synthesis and some of the properties of these new polymers are briefly explored. Water s o l u b l e polymers a r e of s p e c i a l i n t e r e s t today f o r b i o medical, o i l recovery, water p u r i f i c a t i o n , b o i l e r s c a l e prevent i o n , coatings and many other a p p l i c a t i o n s . Many o f the polymers under study c o n t a i n hydroxyl and/or c a r b o x y l i c a c i d f u n c t i o n a l i t i e s , which c o n t r i b u t e d needed h y d r o p h i l i c i t y , r e a c t i v i t y and other p r o p e r t i e s to the base polymer. As p a r t of an ongoing program to prepare and study new, water s o l u b l e polymers, a t t e n t i o n was focused on the p o s s i b l e r a d i c a l copolymerization of 4,7-dihydro-l,3-dioxepins w i t h maleic anhy d r i d e (MA) and maleimides. A wide v a r i e t y of 4,7-dihydro-l,3-dioxepins o r l,3-dioxep-5enes are known (1,2). These c y c l i c a c e t a l or k e t a l compounds a r e conveniently prepared by the a c i d c a t a l y z e d r e a c t i o n of c i s - 2 1

Current address: University of Wisconsin, Madison, WI 53706.

0097-6156/82/0195-0371$06.00/0 © 1982 American Chemical Society

Butler and Kresta; Cyclopolymerization and Polymers with Chain-Ring Structures ACS Symposium Series; American Chemical Society: Washington, DC, 1982.

372

POLYMERS WITH CHAIN-RING STRUCTURES

b u t e n e - l , 4 - d i o l w i t h aldehydes, ketones and a c e t a l s (1.). For t h i s study, monomers I and I I were prepared. The unsymmetrical isomer of I I , i . e . , I l l was a l s o prepared from I I . CH = CH V

CH2

^

0

ÇH *^ ^ÇH2 CH CH ^ CH 2

2

2


2

I

II IA. IB. IC. ID. IE.

III

f

R=H, R =H R=H, R =CH ( C H ) R=H, R C H R=CH , R =CH R=H, R = -CH=CH f

3

2

, =

6

5

f

3

3

1

2

This study was undertaken to f i n d out i f 1,3-dioxepins, f u n c t i o n i n g as e l e c t r o n donor monomers, would copolymerize with the strong e l e c t r o n acceptor monomer MA, to give a new f a m i l y of heret o f o r e unreported 1:1 a l t e r n a t i n g copolymers. I t was hoped that t y i n g the hydroxyl groups of the c i s - 2 - b u t e n e - l , 4 - d i o l i n t o a c y c l i c planar or c h a i r (3,16) s t r u c t u r e would decrease s t e r i c h i n d rance and enhance double bond p o l y m e r i z a t i o n r e a c t i v i t y . Sterling (4) had p r e v i o u s l y shown that 2 - s u b s t i t u t e d 1,3-dioxepins would copolymerize with v i n y l i d e n e c h l o r i d e , butadiene and methyl i s o propenyl ketone and i t i s w e l l known that unsaturated c y c l i c o l e f i n s (5), i n c l u d i n g unsaturated c y c l i c ethers (6-8) copolymeri z e i n a 1:1 a l t e r n a t i n g f a s h i o n with MA. A second goal was to f i n d out i f t h i s s y n t h e t i c route could provide a path to h e r e t o f o r e unreported head-to-head poly (4-hydroxycrotonic a c i d ) and poly (γcrotonolactone) v i a h y d r o l y s i s and rearrangement r e a c t i o n s of the 1,3-dioxepin-alt-MA copolymers. Since our i n i t i a l r e p o r t (9) on t h i s s u b j e c t , Yokoyama and H a l l (10) published t h e i r r e s u l t s on the f r e e - r a d i c a l i n i t i a t e d copolymerization of IA with MA to o b t a i n a 1:1 a l t e r n a t i n g copoly mer. Yokoyama and H a l l (10) a l s o confirmed that the IA-MA copoly mer i s a source of head-to-head poly (4-hydroxycrotonic acid)· Measurements - HNMR s p e c t r a were determined on a Bruker WP200 NMR spectrometer at 200 MH , u s i n g t e t r a m e t h y l s i l a n e as a r e f e r ence. I n f r a r e d (IR) s p e c t r a (KBr) were recorded with a P e r k i n Elmer 580 spectrophotometer. Molecular weights (F^) and d i s p e r s i v i t y (Mtf/Mn) values were estimated from data c o l l e c t e d on the Waters GPC 301 equipment, u s i n g t e t r a h y d r o f u r a n s o l v e n t . Inherent v i s c o s i t i e s , ni b> were determined i n Cannon-Ubbelohde viscometers (0.4g/100ml s o l v e n t at 30°C). D i f f e r e n t i a l thermal and thermo g r a v i m e t r i c analyses p r o f i l e s were obtained on the DuPont 900 DTA, Z

n


29.

CULBERTSON A N D AULABAUGH

4,7-Dihydro-l,3-dioxepins

equipped with a DSC c e l l , 950 TGA and 990 thermal a n a l y z e r u n i t s . A Hewlett-Packard 5610A Gas Chromatograph ( g c ) , w i t h 10% FFAP on Chromosorb W (AW-DMCS) column using N c a r r i e r gas was used f o r monomer p u r i t y s t u d i e s . A c i d numbers were determined by nonaqueous t i t r a t i o n of the copolymers i n acetone, u s i n g 0.1N sodium hydrox ide t i t r a n t , p h e n o l p h t h a l e i n i n d i c a t o r and 0*1N s u l f u r i c a c i d back titrant. Elemental analyses were performed by Huffman L a b o r a t o r i e s , Inc., Wheatridge, Colorado. Solvents and I n i t i a t o r s . A l l p o l y m e r i z a t i o n s o l v e n t s , e t h y l acetate (EA),1,2-dichloroethane (DCE), methyl e t h y l ketone (MEK), cyclohexanone (CH), toluene and t e t r a h y d r o f u r a n (THF) were p u r i f i e d by standard procedures (12) and stored under N o r over molecular s i e v e s . A l l other s o l v e n t s used, Ν,Ν-dimethylformamide (DMF), d i me t h y l s u l f oxide (DMSO), γ-butyrolactone, hexane, d i e t h y l e t h e r , acetone, e t c . , were AR grade m a t e r i a l s . I n i t i a t o r s , a z o b i s i s o b u t y r o n i t r i l e (AIBN), d i - t - b u t y l p e r o x i d e (DTBP), l a u r y l peroxide (LP) and benzoyl peroxide (BPO) were r e c r y s t a l l i z e d (AIBN and BPO) or used as r e c e i v e d from s u p p l i e r s . Monomers. MA was p u r i f i e d by m u l t i p l e r e c r y s t a l l i z a t i o n s and/ or s u b l i n i a t i o n . The monomer N-phenylmaleimide was prepared by a known procedure (13) and r e c r y s t a l l i z e d s e v e r a l times to o b t a i n high p u r i t y . Treatment o f c i s - 2 - b u t e n e - l , 4 - d i o l w i t h a two-fold molar excess of a c e t i c anhydride f o r 6 h r . a t 100°C was the method of choice to prepare c i s - 2 - b u t e n e - l , 4 - d i o l d i a c e t a t e , bp 55-60°C/ 0.1mm [ l i t . : 120-l°C/18mm ( 2 8 ) ] ) . Dimethyl maleate and d i - t i b u t y l fumarate were d r i e d over sodium s u l f a t e and d i s t i l l e d . The c i s - 2 - b u t e n e - l , 4 - d i o l s t a r t i n g m a t e r i a l contained ca. 8% trans isomer, as shown by NMR. Synthesis of 4,7-Dihydro-l,3-dioxepins ( I A ) . Paraformaldehyde (45.Og, 1,5 mol) was combined w i t h c i s - 2 - b u t e n e - l 4 - d i o l (134.Og, 1.52 mol), 0.37g p - t o l u e n e s u l f o n i c a c i d and 40 ml toluene. The mixture was heated a t r e f l u x w i t h a n i t r o g e n purge u n t i l a p p r o x i mately 16 ml of water was c o l l e c t e d i n a Dean-Stark t r a p . Dis t i l l a t i o n o f the remaining r e a c t i o n mixture gave 130g (80% y i e l d ) of crude IA, bp 120-125°C. R e d i s t i l l a t i o n over potassium carbon ate gave p o l y m e r i z a t i o n grade monomer, with gc showing >99% p u r i t y : bp 125-127°C/760mm [ l i t . : 124°C/760mm (14), 127.8-128.2°C/734mm (11), 127°C/760mm (15)]. The NMR spectrum (CDC1 ) gave peaks a t 65.68 (-CH=CH-), 64.8 (-0CH 0-), 64.2ppm (-CH 0-), and no exchangable protons. Synthesis o f 4,7-Dihydro-2-isopropyl-l,3-dioxepin ( I B ) . I s o butyraldehyde (79.4g, 1.10 mol) was combined slowly with c i s - 2 b u t e n e - l , 4 - d i o l (100.Og, 1.13 mol). A f t e r a d d i t i o n was complete, the r e a c t i o n mixture was s t i r r e d under n i t r o g e n f o r 1 h r . a t room temperature. Formation of the hemiacetal was s l i g h t l y exothermic, r a i s i n g the r e a c t i o n mixture t o 30°C. The hemiacetal mixture was added slowly a t a c o n t r o l l e d r a t e to a r e f l u x i n g toluene (150 ml) s o l u t i o n c o n t a i n i n g 0.24g p - t o l u e n e s u l f o n i c a c i d . Under a n i t rogen purge, about 13 ml of water was c o l l e c t e d i n a Dean-Stark t r a p . The toluene s o l u t i o n of the product was f r a c t i o n a t e d through 2


373

2

>

3

2

2



374

POLYMERS WITH CHAIN-RING

STRUCTURES

Table I Monomers

Yield

IA IB IC ID IE IF II III

80 64 55 86 36 20 70 —

a

a

bp, °C/mm 125-127 66-67/0.06 76-77/0.3 59-60/27 53-55/13 53-55/4.5 60-61/1.0 67-69.5/1.0

References 11 17 18 19,22 18 11 11,18 21

NMR data showed a mixture o f I I / I I I w i t h c a . 65% I I I .



29.

CULBERTSON

AND AULABAUGH

4,7-Dihydro-l ,3-dioxepins

375

a Vigreux column a t reduced pressure to o b t a i n a 92.Og (64% y i e l d ) of crude IB, bp 66-76°C/0.06mm. R e d i s t i l l a t i o n over potassium carbonate gave p o l y m e r i z a t i o n grade monomer, w i t h gc showing >99% p u r i t y : bp 66-67°c/0.06mm [lit.:105°C/100mm (17), 170-170.6°C/735 mm (11)]. The NMR spectrum ( C D C I 3 ) gave peaks a t 61.6-2.2 (-CH99.5% p u r i t y : bp 59-60°C/27mm [ l i t . : 41°C/6.0mm (19), 108-109°C/60mm ( 2 ) , 144.5147°C/755mm (20)]. N * 1.4472 [ l i t . : N * 1.4465 (20)]. The NMR spectrum ( C D C I 3 ) gave peaks a t 65.6 (-CH=CH-),64.2 (-CH2O-) and 61.4ppm ( C H 3 ) . 2 2

d

5

2 i +

5

d

Synthesis o f 4 , 7 - D i h y d r o - 2 - v i n y l - l , 3 - d i o x e p i n ( I E ) . Following a p u b l i s h e d procedure (18), crude I E was prepared from a c r o l e i n and c i s - 2 - b u t e n e - l , 4 - d i o l i n a 39% y i e l d . R e d i s t i l l a t i o n gave p o l y m e r i z a t i o n grade monomer, bp 53-55°C/13mm. The NMR spectrum showed a complex m u l t i p l e t a t 65.5-5.1, m u l t i p l e t a t 64.2-4.05ppm (-CH2O-), and no exchangeable protons. Synthesis o f 4,7-Dihydro-2(2-propenyl) 1,3-dioxepins ( I F ) . Using the Brannock and Lappen (11) procedure, crotonaldehyde was condensed w i t h c i s - 2 - b u t e n e - l , 4 - d i o l t o o b t a i n a 20% y i e l d o f I F , bp 53-55°C/4.5mm [ l i t . : 54-55°C/4.5mm (11)]. Synthesis of 7,12-Dioxaspiro (5,6)-dodec-9-ene ( I I ) . Cyclohexanone (49g, 0.5 mol) was combined w i t h c i s - 2 - b u t e n e - l , - 4 - d i o l , (44.Og, 0.5 mol), 1. Og p - t o l u e n e s u l f o n i c a c i d and 300ml toluene. The mixture was heated(5 hr.) a t r e f l u x under a n i t r o g e n purge w i t h approximately 8.5 ml water c o l l e c t e d i n a Dean-Stark t r a p . After c o o l i n g , the a c i d was n e u t r a l i z e d w i t h sodium methoxide, s o l u t i o n f i l t e r e d , toluene evaporated and the product d i s t i l l e d to o b t a i n 59g (70% y i e l d ) o f crude I I , bp 59-61°C/lmm. R e d i s t i l l a t i o n gave p o l y m e r i z a t i o n grade monomer, bp 60-61°C/lmm [ l i t . : 54°C/0.2mm (18,19), 94°C/10mm (11), 76-76.5°C/8mm (21)], N 1.4878 [ l i t . : 2 1

d


376


STRUCTURES

2 0

N 1.4876 (11)]. The NMR spectrum gave peaks a t 65.68 (-CH=CH-), 64.25 (-CH 0-) and a complex m u l t i p l e t a t 61.9-1.3ppm (10 methylene p r o t o n s ) . Synthesis of 7,12-Dioxaspiro (5,6)-dodec-8-ene ( I I I ) . Monomer I I I (50.4g, 0.3 mol), was combined w i t h 30 ml t e r t - b u t y l a l c o h o l and 15g (0.14 mol) of potassium t e r t - b u t o x i d e . The mixture was heated i n a sealed g l a s s r e a c t o r f o r 6 h r . a t 120°C. A f t e r c o o l ing, the s o l u t i o n was d i l u t e d w i t h d i e t h y l ether and e x t r a c t e d with water to remove base. Evaporation of the d i e t h y l ether and d i s t i l l a t i o n gave a crude mixture of I I and I I I as a water white l i q u i d , bp 67-69.5°C/lmm [ l i t . : 76-76.5°C/8mm f o r I I I (21)]. The NMR spectrum w i t h peaks at 66.07, 65.66, 64.83, 64.24, 63.85, 62.28 and 61.9-l.3ppm, i n d i c a t e d that the I I / I I I mixture contained ca. 65% I I I . Attempted Homopolymerization o f 1,3-Dioxepins. The r e q u i r e d amount of monomer and i n i t i a t o r (or monomer, s o l v e n t and i n i t i a t o r ) were weighed i n t o a g l a s s serum b o t t l e , the system purged w i t h n i t r o g e n and the b o t t l e sealed w i t h a Neoprene stopper. Polymeriz a t i o n s were run i n a shaker bath f o r 6.5 h r . at 75°C. Combina t i o n s examined were IA (10.Og, 0.1 mol) w i t h O.lg AIBN, IB (7.25g, 0.05 mol) w i t h 0.15g AIBN, IC (12.Og, 0.06 mol) w i t h 0.18g AIBN, ID (7.0g, 0.05 mol) w i t h 5.0ml MEK and O.lg AIBN, ID (12.6g, 0.09 mol) w i t h 9 . 0 m l toluene and 0. l g AIBN, and IE (8.0g, 0.06 mol) with 8.0ml toluene and 0.16g AIBN. Reactions were terminated by c o o l ing and combining the r e a c t i o n mixtures w i t h a 50/50 (v/v) hexane/ d i e t h y l ether mixture. Polymer f a i l e d to form i n a l l systems. MA-l,3-Dioxepin Copolymerizations. Copolymerizations i n Tables I I and I I I were run under n i t r o g e n i n g l a s s f l a s k s f i t t e d with a mechanical s t i r r e r , r e f l u x condenser, n i t r o g e n i n l e t and a thermometer. Where incremental a d d i t i o n of i n i t i a t o r was employed, the f l a s k s were a l s o f i t t e d w i t h an a d d i t i o n f u n n e l . Equimolar amounts of 1,3-dioxepin, MA, s o l v e n t and i n i t i a t o r were weighed i n t o the f l a s k s and p o l y m e r i z a t i o n s run a t the time/temperature c o n d i t i o n s shown. In some runs the i n i t i a t o r was d i s s o l v e d i n the minimum amount of s o l v e n t and added a t a c o n t r o l l e d r a t e during p o l y m e r i z a t i o n . A f t e r c o o l i n g and d i l u t i o n w i t h acetone, the copolymers were p r e c i p i t a t e d w i t h d i e t h y l ether. The polymers were p u r i f i e d by d i s s o l v i n g i n acetone, r e p r e c i p i t a t i n g i n t o d i e t h y l ether and d r y i n g i n vacuo a t 58°C. The new polymers were white powders, which were s o l u b l e i n acetone, chloroform, water (with r e a c t i o n ) , EA, DMF, DMSO and THF. The NMR spectrum ( a c e t o n e - d or DMSO-d^) of each copolymer e x h i b i t e d peaks f o r polymerized MA r e s i d u e s a t 63-4, c y c l i c a c e t a l or k e t a l peaks a t 63-4 (not w e l l r e s o l v e d due to o v e r l a p ) , and no f r e e MA peaks were shown a t 67.04 or 67.27ppm. In a d d i t i o n , the NMR s p e c t r a of the IA, IB, IC, ID and I I copolymers had resonance peaks, r e s p e c t i v e l y , a t 4.7 (0CH ), 0.9 (2CH ), 7.35 ( C 6 H 5 ) , 1.3 ( C H 3 ) and 61.5ppm (10 methylene p r o t o n s ) . The IR spectrum of each copolymer i n c l u d e d absorpt i o n bands at 1855, 1775, 1100 and 925 cm . In some cases the strong band a t 1775 had a weak shoulder a t 1720-1725 cm" , w i t h NMR showing a c t i v e protons f o r these s i t u a t i o n s . d


2

6

2

3

-1

1



a

*

h

g

f

e

d

k c

2

f

±

AIBN AIBN AIBN AIBN BPO AIBN AIBN AIBN AIBN DTBP AIBN b

a

c

c

a

d

a

a

a

d.5) (1.5) (1.5) (1.5) (1.5)* (2.0) (3.0)? d.5) (1.5) (1.5) (2.0)

I n i t . (wt%) 62 75 55 60 54 64 76 65 52 32 71

7.0 7.0 5.0 8.0 20.0 7.0 6.0 8.0 7.0 7.0 17.0 17.0

75 80 80 75 80 75 75 80 75 130 80 80 —

Yield %

Time, h r .

Copolymerizations

Temp. °C

(IA)-MA

S o l u t i o n of i n i t i a t o r added incremently Slow ( c o n t r o l l e d ) a d d i t i o n of i n i t i a t o r s o l u t i o n d u r i n g course of p o l y m e r i z a t i o n One shot a d d i t i o n of i n i t i a t o r AIBN (1.5 wt%) added a t s t a r t and 0.5 wt% AIBN added a f t e r 4 h r . Hinh 0.23 d l / g (DMF). Z n C l (1%, wt/wt) added a t s t a r t of r e a c t i o n EA/DCE (50/50,v/v) used ninh 0.34 d l / g (DMF) Copolymer p r e c i p i t a t e d as formed i n DCE

1

EA (10) DCE ( 1 0 ) Toluene (10) MEK (10) MEK (10) DCE (10) y EA/DCE (10)8 MEK (10) MEK (10) CH (10) MEK (13.5) MEK (6.7)

7.35 7.35 7.35 7.35 7.35 10.00 6.86 7.35 7.35 7.35 10.00 5.00

7.51 7.51 7.51 7.51 7.51 10.20 7.01 7.51 7.51 7.51 10.20 5.10

(g)

Solvent

MA,g

IA.g

4,7-Dihydro-l,3-dioxepin

Table I I


e

(1.61)

1264

(1.44)

2850 (1.95) 1700 ( 1 . 6 0 )

1800

h


a

n

0 8

(g)

DMF

5.00 5.00 14.71 4.71 7.35 24.52 19.14 4.71 7.35 73.55 7.35 4.90 9.80 9.80

MA,

(g)

k

k

k

k

k

k

k

DCE ( 1 0 ) DCE ( 1 4 ) MEK (33) EA/DCE (96) DCE (12) DCE ( 5 ) DCE ( 7 8 ) DCE ( 8 ) MEK (10) DCE ( 1 5 ) DCE ( 1 5 )

k

(10)

(7.55)

CHCI3

MEK

Solvent 75-80 75 70-75 75 75-80 75-80 75-80 75-80 75-80 75 70-75 75 80 80

2.0 2.0 1.5a 3.0 1.5b 2.0C 2.0 3.0b 1.5 1.0 1.5b 3.0 1.5 1.5 a

a

a

b

b

b

b

a

a

Temp. °C

AIBN wt.%

b

g

f

e

d

c

k

i n n

Hard G e l Hqrd G e l 6200 (1.69) 80 69

—

—

h

d

(1.35)3 (1.27) (1.52) (1.61) (2.00) » (2.09)f g 2100 (1.61) 8100 ( 1 . 8 0 ) i

2000 1600 1650 2100 3400 6400

Mu (M^/Mn)

47 53 41 65 65 60 46 65 75 55

Yield %

e

j n 0.03 d l / g (DMF) Copolymer p r e c i p i t a t e d as formed i n DCE

7.0 22.0 8.0 7.0 6.0 8.0 20.0 7.0 7.0 6.5 5.5 3.0 7.0 7.0

Time,nr.

Copolymerizations

I n i t i a t o r added at s t a r t of r e a c t i o n b Incremental a d d i t i o n o f i n i t i a t o r s o l u t i o n 1% AIBN added a t s t a r t and 1% AIBN booster added a f t e r 6 h r . A c i d No. 510 showing c a . 1:1 copolymer ninh 0.05 d l / g (DMF) ninh 0.12 d l / g (DMF) ninh 0.09 d l / g (DMF) ninh 0.08 d l / g (DMF) inh 0 · /g < >

d l

(g)

IB (7.25) IB (7.25) IB (21.33) IB (6.82) IC (13.77) ID (32.04) ID (25.13) ID (6.82) ID (9.61) ID (98.12) IE (9.46) IF (7.01) I I (16.08) ΙΙΊ: (16.08)

Dioxepin

Assorted 1,3-Dioxepin-MA

Table I I I



29.

CULBERTSON


AND AULABAUGH

379

For copolymerizations i n Table IV, monomers (75%) s o l i d s ) , DCE and AIBN (2.0 wt%) were combined and sealed (Neoprene stopper) under n i t r o g e n i n 50ml g l a s s serum b o t t l e s . The p o l y m e r i z a t i o n s were run i n a shaker bath f o r 5 h r . a t 70°C. Polymer recovery and p u r i f i c a t i o n was the same as p r e v i o u s l y d e s c r i b e d . H y d r o l y s i s of MA-l,3-Dioxepin Copolymers. IA-MA copolymer (2.00g) was combined with 50ml d e i o n i z e d water and s t i r r e d a t room temperature f o r 48 h r . A f t e r 12 h r . the d i s p e r s i o n became a homo geneous s o l u t i o n . Evaporation of the water and prolonged d r y i n g i n vacuo over phosphorus pentoxide a t room temperature gave a 2.25g y i e l d of white polymer s o l u b l e i n THF, MEK, DMF and DMSO. GPC showed 1853 and d i s p e r s i v i t y o f 1.4. The IR spectrum had absorptions a t 3500, 1720 (weak shoulder a t 1760), four peaks i n area 1200-1000 and no anhydride absorptions a t 1815 and 1775 cm" . TGA showed onset o f decomposition a t 75°C, with 20% weight l o s s from 75-300°C (theory f o r l o s s o f CHoO and HoO t o form l a c t o n e 22%). Anal. C a l c d . f o r ( C Q H 0 ) : C, 50.0; H, 5.55. Found: C, 49.50; H, 5.66. Copolymers IA-MA (3.0g) and IB-ΜΑ (3.0g) were suspended i n 50 ml of d e i o n i z e d water w i t h 1 drop cone, h y d r o c h l o r i c a c i d . After 12 h r . the suspensions changed to c l e a r s o l u t i o n s . The s o l u t i o n s were heated f o r 1 h r . a t r e f l u x , i n s u r i n g complete h y d r o l y s i s and the water was evaporated a t ambient c o n d i t i o n s and i n vacuo a t room temperature. The r e s i d u e s were taken up i n MEK and the p o l y mers p r e c i p i t a t e d i n t o a l a r g e volume of d i e t h y l e t h e r . The IR s p e c t r a of the d r i e d copolymers were almost i d e n t i c a l , w i t h both polymers showing absorptions a t 3650-3300, 2980-2900, 1720, 1390, 1135, 965 and 845 cm." A n a l . C a l c d . f o r hydrolyzed IA-MA ( 0 β Η 0 ) : C, 47.05; H, 5.88. Found: C, 46.65; H, 5.98. Anal. Calcd. f o r hydrolyzed IB-ΜΑ ( C g H 0 ) : C, 47.05; H, 5.88. Found: C,46.72; H, 5.97. A c i d Rearrangement o f 1,3-Dioxepin-MA Copolymers. IA-MA, IB-ΜΑ and ID-ΜΑ copolymers (3.0g) were combined with 0.1N hydro c h l o r i c a c i d (80ml). The polymer suspensions were s t i r r e d and heated f o r 12 hr. a t 50°C and 4 h r . a t 70°C. Isobutyraldehyde odor was detected coming from the IB-ΜΑ system. The polymers were c o l l e c t e d , washed with d e i o n i z e d water and d r i e d i n vacuo over phosphorus pentoxide a t room temperature to o b t a i n s l i g h t l y yellow c o l o r e d m a t e r i a l s s o l u b l e i n DMF and DMSO. The IR spectrum o f each copolymer e x h i b i t e d absorptions a t 3350, 2650, 1760 (with a s h o u l der a t 1720-1700), 1630, 1165 and 1120 cm" , w i t h no anhydride absorptions a t 1855 and 1775 cm" and no c y c l i c a c e t a l absorptions i n the 1200-1000 cm"" r e g i o n . The C NMR s p e c t r a , though not w e l l r e s o l v e d , c l e a r l y showed no methyl protons f o r the recovered IB-ΜΑ and ID-ΜΑ copolymers. Copolymer ID-MA (10.2g) was combined w i t h 10ml d e i o n i z e d water, 40ml i s o p r o p y l a l c o h o l and 0.5g cone, h y d r o c h l o r i c a c i d . The sus1

1 2

6

n

1

1 2

1 2

6

6

η

n

1

1

1

1 3



STRUCTURES

IV This b r i e f study shows that ΙΑ-ID monomers tend to copolymer i z e i n a 1:1 f a s h i o n w i t h MA, r e g a r d l e s s of c o n d i t i o n s and feed ratios. This suggests the p o s s i b i l i t y that a charge i n t e r a c t i o n f a c i l i t a t e these a l t e r n a t i n g c o p o l y m e r i z a t i o n s . Attempts were made to determine the CTC e q u i l i b r i u m constants f o r the IA-MA and IB-ΜΑ comonomer p a i r s . Chloroform s o l u t i o n s of IA-IF, I I , I I I and MA are c o l o r l e s s , but mixtures of the 1,3-dioxepin and MA s o l u t i o n s , such as IA-MA, IB-ΜΑ, e t c . , o f t e n become s l i g h t l y yellow c o l o r e d . I t was thought that the c o l o r development could be a t t r i b u t e d to the formation of a 1,3-dioxepin e l e c t r o n donor-MA e l e c t r o n acceptor CTC. How ever, H'NMR s t u d i e s , using the Hanna-Ashbaught (30) procedure w i t h C D C I 3 s o l v e n t , f a i l e d to show any s i g n i f i c a n t i n t e r a c t i o n between IA-MA or IB-ΜΑ. Yokoyama and H a l l (10) confirm t h i s f i n d i n g f o r the IA-MA system. Since an e q u i l i b r i u m constant (K) could not be determined f o r the IA-MA and IB-ΜΑ system, Κ must have a n e g l i g i b l e s m a l l (K75°C) f o r prolonged periods the m a t e r i a l s slowly convert to new •ÇH - Ç H — C0 H C0 H 2

2

- CH - CH — CH fcH 2

2

R ^ R

polymers w i t h a s t r o n g l a c t o n e c a r b o n y l absorptions i n the IR a t 1760 cm." T h i s i s not s u r p r i s i n g , s i n c e Pawloski (1) reported that c a r b o x y l i c a c i d s r e a c t w i t h 1,3-dioxepins to produce 4hydroxy-2-butenyl e s t e r s . H y d r o l y s i s of IA-MA and IB-ΜΑ copolymers i n d e i o n i z e d water with only a t r a c e amount of h y d r o c h l o r i c a c i d gave complete hy d r o l y s i s of both the anhydride and a c e t a l m o i e t i e s . Elemental, IR and NMR analyses were s u p p o r t i v e of s t r u c t u r e V I , head-tohead poly (4-hydroxycrotonic a c i d ) , p r o d u c t i o n . These r e s u l t s were confirmed by Yokoyama and H a l l (10), u s i n g the IA-MA a l t e r n a t i n g copolymer. 1

-CHCH 0H 2

-CH-

-CHC0 H

C0 H

2

2

-CHCH 0H 2

VI Treatment of IA-MA, IB-ΜΑ and ID-ΜΑ copolymers f o r prolonged periods w i t h hot h y d r o c h l o r i c a c i d produced DMF, DMSO and γ-butyro-


29.

4,7-Dihydro-l ,3-dioxepins

CULBERTSON AND AULABAUGH

387

l a c t o n e s o l u b l e m a t e r i a l s w i t h a strong l a c t o n e carbonyl absorp t i o n band i n the IR a t 1760 cm" and weak bands f o r hydroxyl and c a r b o x y l i c a c i d r e s i d u e s . A heterogeneous mixture of the ID-MA copolymer i n a w a t e r / i s o p r o p y l a l c o h o l mixture, c o n t a i n i n g hydro c h l o r i c a c i d , a l s o produced a f t e r 12 h r . r e a c t i o n a DMF s o l u b l e copolymer. S i m i l a r to the previous r e s u l t s , the new polymer ex h i b i t e d a strong l a c t o n e carbonyl absorption i n the IR a t 1760 cm." The C NMR s p e c t r a o f the copolymer confirmed absence o f methyl protons f o r the recovered IB-ΜΑ and ID-ΜΑ polymers. E l e mental analyses data f o r the v a r i o u s copolymers was supportive o f m a t e r i a l s being produced with c o n s i d e r a b l e l a c t o n e r i n g s . The a c i d t r e a t e d ID-ΜΑ copolymer, with l a c t o n e , a c i d and hy d r o x y l absorptions i n the IR, was heated f o r 2 h r . a t 200°C. The IR spectrum of the recovered polymer showed c o n s i d e r a b l e sharpen ing of the 1760 cm" band and elemental a n a l y s i s supportive o f head-to-head poly (γ-crotonolactone), V I I , p r o d u c t i o n . However, absorptions i n the same spectrum suggested the polymer r e t a i n e d a small amount o f c a r b o x y l i c a c i d and hydroxyl f u n c t i o n a l i t y . 1


1

1 3

1

CH

CH

CH

I

I

I

I

V

CHo

CHo

C

v

V

C

CH

VII The thermal p r o p e r t i e s o f the ID-ΜΑ, IB-ΜΑ and ID-ΜΑ copoly mers were examined, a f t e r d i s c o v e r y that these copolymers rearrange s u b s t a n t i a l l y to l a c t o n e r i n g c o n t a i n i n g m a t e r i a l s on exposure to strong a c i d and f i n d i n g from IR s t u d i e s that these m a t e r i a l s o f t e n contained absorptions i n d i c a t i v e o f c a r b o x y l i c a c i d r e s i d u e s . Copolymer IB-ΜΑ was heated under n i t r o g e n a t 235-240°C with the o f f gases c o l l e c t e d i n a c o l d t r a p . The c o l d trap contained isobutyraldehyde, i d e n t i f i e d both by odor and IR. In a second experiment, the o f f gases were a l s o absorbed i n t o 2 , 4 - d i n i t r o phenylhydrazine (DNPH) s o l u t i o n . A f t e r about t e n minutes the DNPH d e r i v a t i v e s t a r t e d forming i n the c o l l e c t i o n t r a p . A 26.4% weight l o s s was observed during h e a t i n g (6 h r . ) , compared with a theo r e t i c a l weight l o s s f o r isobutyraldehyde coming from a 1:1 copoly mer of 23.7%. The IR spectrum of the l i g h t t a n c o l o r e d m a t e r i a l , which was s o l u b l e only i n p o l a r s o l v e n t s , e x h i b i t e d a strong l a c tone carbonyl absorption a t 1760 cm." Under s i m i l a r c o n d i t i o n s , copolymers IA-MA and ID-ΜΑ gave o f f , r e s p e c t i v e l y , formaldehyde and acetone, i d e n t i f i e d as t h e i r 2,4-dinitrophenylhydrozones. The IR s p e c t r a of these two thermolyzed copolymers a l s o e x h i b i t e d strong l a c t o n e absorptions a t 1760 and 1165 cm." Cyclohexanone s o l u t i o n s of IA-MA and IB-ΜΑ copolymer were heated a t r e f l u x f o r extended p e r i o d s . The IR spectrum o f the recovered IA-MA copolymer was s u b s t a n t i a l l y the same as the IR o f the s t a r t i n g m a t e r i a l . In c o n t r a s t , absorptions i n the IR o f the 1

1



388

STRUCTURES

recovered IB-ΜΑ copolymer included CH2 new bands i n the 1760 and 1165 cm" r e g i o n , i n d i c a t i v e of l a c t o n e m o i e t 0 ies. A small amount of cone, h y d r o c h l o r i c a c i d was added to non VIII aqueous s o l u t i o n s of 1,3-di/Oxepin-alt-MA copolymers and the mix tures heated to o b t a i n m a t e r iCH a l s w i tCH h l a c t o n e r i n g s . For example, a MEK s o l u t i o n of copolymer ID-MA (25% s o l i d s ) was combined w i t h 1% by wt. cone. HC1 and the mixture heated at 70-75°C. The IR spectrum, whith absorptions a t 1760 and 1165 cm"" , showed the r e covered copolymer was s u b s t a n t i a l l y converted t o a lactone m a t e r i a l . NMR s p e c t r a l changes were a l s o supportive o f l a c t o n e formation. The C NMR spectrum showed no methyl protons. Low molecular weight h e a d - t o - t a i l poly (γ-crotonolactone), V I I I , was prepared f o r comparison w i t h the l a c t o n e polymers pre pared i n t h i s study. The IR spectrum of the a n i o n i c a l l y prepared m a t e r i a l ( V I I I ) , with strong absorptions i n the r e g i o n c t r a of V I I and V I I I were a l s o s i m i l a r , w i t h each showing absorptions f o r methylene and methine protons. Concluding, a l l evidence c o l l e c t e d to date suggests a path has been found to p r e v i o u s l y unreported head-tohead poly (4-hydroxy-crotonic a c i d ) , V I , and head-to-head poly (γ-crotonolactone), V I I , v i a h y d r o l y s i s and rearrangement r e a c t i o n s of 1:1 a l t e r n a t i n g 1,3-dioxepin-MA copolymers. Amide d e r i v a t i v e s of the 1,3-dioxepin-MA and head-to-head poly (γ-crotonolactone) polymers were r e a d i l y prepared. However, the cursory s t u d i e s conducted f a i l to supply an answer as to why amide formation i s below t h e o r e t i c a l . I t was pointed out e a r l i e r that a c i d and anhydride c o n t a i n i n g polymers have many p o s s i b l e a p p l i c a t i o n s . With the exception o f c u r i n g epoxide r e s i n s and examination of p o s s i b l e b i o l o g i c a l a c t i v i t y , l i t t l e has been done to explore uses f o r the copolymers de veloped i n t h i s study. A standard epoxide r e s i n (Epon 828, 25.2g) was combined w i t h 15 ml MEK, 15.Og ID-alt-MA copolymer and 0.2g dimethylbenzylamine, g i v i n g a homogeneous mixture w i t h 73% s o l i d s . Films (3 m i l ) were drawn on g l a s s and s t a i n l e s s s t e e l p l a t e s . The f i l m s were a i r d r i e d and cured a t 300°F f o r 60 min. The cured f i l m s e x h i b i t e d high g l o s s , high adhesion and e x c e l l e n t s o l v e n t r e s i s t a n c e on both s u r f a c e s .


1

1

1 3


29.

CULBERTSON

AND AULABAUGH


389

A sample of poly (2,2-dimethy1-4,7-dihydro-l,3-dioxepin-altmaleic anhydride) polymers was f r a c t i o n a t e d and b r i e f l y examined f o r a n t i v i r a l p r o p e r t i e s (31). The copolymer was f r a c t i o n a t e d through Amicon f i l t e r s i n t o a 1,000-10,000 and 10,000-30,000 mol e c u l a r weight cuts. Both molecular weight f r a c t i o n s were examined f o r e f f e c t against mice i n o c u l a t e d ( i p ) with 1 0 E h r l i c h A s c i t e s tumor c e l l s . F i v e days a f t e r i n o c u l a t i o n the animals were s a c r i f i c e d and t o t a l p e r i t o n e a l exudate c e l l s were counted with a hemocytometer. Under these c o n d i t i o n s , O t t e n b r i t e (31) showed that the 1,000-10,000 molecular weight f r a c t i o n o f the ID-ΜΑ copolymer was as e f f e c t i v e as Pyran ( c o n t r o l i n experiment) f o r c o n t r o l o f E h r l i c h A s c i t e s tumor c e l l s . Pyran, the copolymer o f d i v i n y l ether-MA i s a w e l l known antitumor agent (32) and i n t e r f e r o n i n ducer (33). Acknowledgement A p p r e c i a t i o n i s expressed to Ashland Chemical Co. management f o r permission t o p u b l i s h . For a n a l y t i c a l (NMR, DTA, TGA, GPC, IR, etc.) support, a p p r e c i a t i o n i s a l s o expressed to A. J . D i G i o i a , D. R. DeGarmo, C. S. Wu and W. MacCaughey o f the Ashland Chemical A n a l y t i c a l s t a f f .


6

Literature Cited 1. Pawloski, C.E. Chem. Heterocycl. Compounds 1972, 26, 319-411 2. Thuy, V.M.; Maitte, P. Bull. Soc. Chem. Fr. 1975, 11-12 (2), 2558-2560. 3. Soulier, J . ; Farines, M.; Laguerre, A; Bonafos-Bastouill, A. Bull. Soc. Chem. Fr. 1976, 1-2 (2), 307-11. 4. Sterling, G.B. U.S. Patent 3,219,629, 1965; Chem. Abstr. 1966, 64, 5262. 5. Murahashi, S.; Nozakura, S.; Yosufuku, K. Bull, Chem. Soc. Japan 1966, 39 (6), 1338. 6. Kawai, W.; J. Polym. Sci. 1968A, 6 (7), 1945. 7. Kimbrough, R.D., Jr.; Dickson, W.P.; Wilkerson, J.M. III J. Polym. Sci. 1964, B2 (1), 85. 8. Tanaki, H.; Otsu, T., J. Macromol. Chem. 1977, All (9), 1663. 9. Culbertson, B.M.; Aulabaugh, A.E. Polym. Prepr., Am. Chem. Soc, Div. Polym. Chem. 1981, 22 (1), 28-29. 10. Yokoyama, Y.; Hall, H.K., Jr. Macromolecules 1981, 14 (3), 471-5. 11. Brannock, J.C.; Lappin, G.R. J. Org. Chem. 1956, 21, 1366-68. 12. Wibert, K.B. "Laboratory Techniques in Organic Chemistry"; McGraw-Hill, New York, 1960. 13. Cava, M.P.; Deana, A.A.; Muth, K.; Mitchell, M.J. Org. Syn theses 1973, Coll. Vol. 5, 944-946. 14. Sterling, G.B.; Watson, E.J.; Pawoloski, C.E.; U.S. Patent 3,116,298, 1963. 15. Pattison, D.B.; J. Org. Chem. 1957, 22, 662-664. 16. Friebolin, H.; Kabus, S. Nucl. Magnetic Resonance Chem. Proc., Symp. Cagliari, Italy, 1964, 125-32.


POLYMERS WITH CHAIN-RING STRUCTURES


390

17. Sturzenegger, Α.; Zelauskas, J.J. U.S. Patent 3,410,871, 1968; Chem. Abstr. 1970, 73, 87950p. 18. Tinsley, S.W., Jr.; MacPeak, D. L. U. S. Patent 3,337,587, 1967. 19. Sterling, G.B.; Watson, E.J.; Pawloski, C.E. U. S. Patent 3,116,299, 1963. 20. Kimel, W.; Leimgruber, W. Fr. Patent 1,384,099, 1965; Chem. Abstr. 1965, 63, 4263d. 21. Thuy, V.M.; C.R. Acad. Sci., Ser. C 1971, 273 (23), 1655-57; Chem. Abstr. 1972, 76, 85801d. 22. Lorette, N.B.; Howard, W.L. J. Org. Chem. 1960, 25, 521. 23. Shriner, R.L.; Fuson, R.C.; Curtin, D.Y. "The Systematic Identification of Organic Compounds"; John Wiley & Sons, Inc., New York, 1959, pp. 111, 112, 283, 316. 24. Price C.C.; Judge, J.M. Org. Syntheses 1973, Coll. Vol. 5, 255-257. 25. Cherdron, J.H.O.; Ohse, H.; Palm, R.A.; Korte, F. German Patent 1,228,065, 1966. 26. Palm. R.; Ohse, H.; Cherdron, H. Angew. Chem., Int. Ed. Engl. 1966, 5 (12), 994-1000. 27. Komiyama, M.; Hirai, H.J. Polym. Sci, 1976, 14, 1993-2007. 28. Raphael, R.A. J. Chem. Soc. 1962, 401-5. 29. Pawloski, C.E.; Sterling, G.B. U.S. Patent 3,280,148, 1966. 30. Hanna, M.W.; Ashbaugh, A.L. J. Phys. Chem. 1964, 68, 811. 31. Ottenbrite, R.M. Virginia Commonwealth University, private communication. 32. Butler, G.B. J. Macromol. Sci., Chem. 1971, A5, 219. 33. Merigan, T.C. Nature (London) 1967, 214, 416. RECEIVED

February 25,

1982.


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