new polymer additives, 3. telechelic additives for polyolefins

Die Angewandte Makromolekulare Chemie 213 (1993) 207-226 (Nr. 3734)

Institute of Chemical Technology of Organic Materials, University of Technology Vienna, Getreidemarkt 9/162, 1060 Vienna, Austria

New polymer additives, 3*

Telechelic additives for polyolefins

Helmut Wanicek, Heinrich Gruber**, Gerd Greber***

(Received 26 May 1993)

SUMMARY A series of telechelic additives with molecular weights of 500- 1500 for polyolefins

was prepared by reaction of telechelic polyolefins with functional antioxidants, light stabilizers and optical brighteners. The telechelic polyolefins with amino-, carboxy- and aldehyde end groups were obtained by hydrogenation of the corresponding telechelic polybutadienes which were prepared by radical polymerization of butadiene with appropriate functional initiators as well as by anionic polymerization of butadiene and termination with carbon dioxide, ethylene oxide and chloroacetaldehyde dimethyl acetal. Oligomeric polyolefins with stabilizer end groups attached by non-hydrolyzable C-C-bonds were obtained by end-capping of living polybutadiene with appropriate functional additive components and subsequent hydrogenation. Preliminary tests of some of the telechelic additives demonstrated excellent compatibility with polypropylene and efficiencies similar to low-molecular standard additives.

ZUSAMMENFASSUNG: Eine Reihe von neuen telechelen Additiven rnit Molekulargewichten zwischen 500

und 1 500 fur Polyolefine wurden durch Reaktion von funktionellen Antioxidantien, Lichtschutzmitteln und optischen Aufhellern rnit den Endgruppen von telechelen Poly- olefinen hergestellt. Die telechelen Polyolefine rnit Amino-, Carboxy- und Aldehyd- Endgruppen wurden durch katalytische Hydrierung der entsprechenden telechelen Polybutadiene erhalten, die zum einen durch radikalische Polymerisation von Butadien rnit geeigneten funktionellen Startern, zum anderen durch Kettenabbruch von anio- nisch polymerisiertem Butadien mit CO,, Ethylenoxid und Chloracetaldehyddi- methylacetal erhalten wurden. Telechele Stabilisatoren rnit uber hydrolysebestandige C-C-Bindungen gebundenen Wirkstoff-Endgruppen wurden durch Kettenabbruch von lebendem Polybutadien rnit geeigneten Additivkomponenten hergestellt. Orientie-

* Part 2, cf.'. ** Correspondence author. *** Deceased in February 1993.

0 1993 Hiithig & Wepf Verlag, Base1 CCC OOO3-3146/93/$05.00 207

H. Wanicek, H. Gruber, G. Greber

rende Tests einiger der oligomeren Additive zeigten neben hervorragender Vertraglich- keit mit Polypropylen ahnliche Wirksamkeiten wie kommerzielle niedermolekulare Vergleichssubstanzen.

Introduction

Polymerizable and polymeric additives, their preparation, potential use and effectiveness have received a substantial amount of attention in recent years since low-molecular-weight stabilizers can be lost from plastic materials by exudation, volatilization and leaching during fabrication or e n d - ~ s e ~ - ~ . For any particular stabilizer its effectiveness and permanence in polymers depends on its - distribution and diffusion in polymers, - compatibility with polymers, - volatility, - extractability from polymers.

Generally, these requirements can be met by means of stabilizers having an increased molecular weight and a proper molecular architecture. Conse- quently, macromolecular stabilizers containing pendent stabilizing moieties have been synthesized by homo- and copolymerization of low-molecular additives containing polymerizable groups as well as by polymer-analogous reactions6- 1 3 . Besides, few examples of oligomers and polymers endcapped with stabilizing moieties on one as well as on both ends of the main chain have been reported' 4- 1 9 .

Frequently, these polymeric additives exhibit relatively high polarity because of their high content of polar stabilizing groups which results in poor compatibility with many polymers. Moreover, the known incompatibility of polymers (namely between the polymer stabilizer and the polymer matrix) limits its applications, and, finally, in many cases the active stabilizing groups are bound to the backbone by thermally and hydrolytically labile bonds.

Presuming that the best compatibility and homogeneous distribution of a macromolecular additive is realized if its chemical structure is as similar as possible to the host polymer, we have synthesized a number of telechelic additives for polyolefins based on polyolefin oligomers with stabilizing end groups of the general structure shown in Scheme 1. To combine optimal effectiveness with low volatility and high compatibility, the molecular weights (M,) of the telechelics were selected predominantly between 500 and 1 500. In this range the concentration of end groups is sufficient and on the other hand the polyolefin chain ensures low polarity and thus good compatibility.

208

New polymer additives, 3

Scheme 1

0-1 polyolefin a S

molecular weight - 500-1500

0 : stabilizing residue, e.g. antioxidant. light stabilizer

Results and discussion

Syntheses of telechelic polyolefins

Telechelic polybutadiene with nitrile end groups (3 a) was prepared by free radical polymerization of butadiene (1) using azoisobutyronitrile (2a) as initiator. 3a was hydrogenated to give the nitrile-telechelic polyolefin (4a) (M, - 850). Using azoisobutyric acid dimethyl ester (2b) as initiator, the ester- telechelic polybutadiene 3 b was obtained and hydrogenated to yield the telechelic polyolefin 4b (M, - 1000) (Scheme 2).

4a was reduced by LiAlH, yielding the amino-terminated polyolefin 5 (M, - 876) and 4 b was converted to the carboxy-terminated polyolefin 6 (M, - 980) by hydrolysis of the ester groups with sodium in ethanol (Scheme 3).

Telechelic polybutadienes were synthesized also by anionic polymerization of butadiene using sodium naphthalene as initiator and termination with functional reagents. Thus, carboxy-, hydroxy-, and acetal-telechelic polybutadienes were synthesized by termination of “living” polybutadiene (7) with C02, ethylene oxide and chloroacetaldehyde dimethyl acetal, respectively. The corresponding telechelic polyolefins 8, 9a, b and 10a, b were obtained by hydrogenation with H2/Pd (8 M, - 680,9a M, - 512,9b M, - 1 500). The acetal-terminated polyolefins 10 a, b were converted to the dialdehydes lOc, d by acid hydrolysis (1Oc M, - 600, 10d M, - 775, Scheme 4).

The telechelic dicarboxylic acid 8 was reacted with SOCl2 and subsequently with ammonia to give the diamide which was dehydrated to the dinitrile 8a. Reduction of 8a with LiAIH, yielded the amino-telechelic polyolefin l l a . In addition, the amino-terminated polyolefin 11 b was obtained from 1Oc by reductive amination and subsequent reduction with LiAlH, (Scheme 5) .

Synthesis of the telechelic additives

The telechelic antioxidants 13 -15 were obtained by reaction of the oligomeric diamines 5, 11 a and the diol 9a with 3-(3,5-di-tert-butyl-4-hydroxy-

209

H. Wanicek. H. Gruber, G. Greber

Scheme 2

n @ +

1

I polymerization

I

Za,b

2a,3a,4a : X = -CN

2b,3b,4b : X = -COOCH3

pheny1)propionic acid chloride (12) (Scheme 6). Depending on the molecular weight of the oligomers the antioxidants contain about 38-50 wt.-Yo active moieties.

For the preparation of the light stabilizers 18a- d the oligomeric dicarboxylic acids 6 and 8 were converted to the acid chlorides and subsequently reacted with 2,2,6,6-tetramethyl-4-aminopiperidine (17a) and 2,2,6,6-tetramethyl-4- hydroxypiperidine (17 b). Another telechelic light stabilizer (18e) was obtained by reductive amination of the oligomeric dialdehyde 10a with 17a (Scheme 7). The telechelics 18a-e contain about 24- 30 wt.-Yo active stabilizing residues.

The stabilizers 13, 18a and 18b exhibit relatively high hydrolytical stability, because the stabilizing groups are attached to the oligomers by amide and ester bonds to tertiary C-atoms. The piperidine groups in 18e are bonded by stable amine bonds. To get additional telechelic additives with non-hydrolyzable

210


Scheme 3

C-COOH _rp_1_ 1 C2H50Na/C2H50H FH3

+ HOOC-C I CH3 CH3

4b

6

Scheme 4

I + Na/naphthalene

CH2-CH2-CH,-CH,

= f j-fH2-!F:, 1. +cop

H O O C - ~ ~ O O H

8

0 0

10c.d

21 1


8 10 Scheme 5

1, +S0CIz

3. +S0Cl2

~ ~ 4 7 t - c ~

2. +NH3

0a

+ LiAIH4 \ /LA,..

1la.b

7

12

Scheme 6

s, i ia ,sa resp. + z CIOC-CH,-CH, ’ \ OH ---+ R - X + ~ ~ X - - R 0 -HCI

13-16

1. -CH30Na

+ 2CH,00C-CH,-CH2 $ ’ \ OH /H<

FH3 13 X = -NH-Y-

CH,

14 -NH-CH2-

I S -O-CH2<H2-

16 -CH2-

212


Scheme 7

6, a resp. + 2 Y G H A R - X i 7 b X - R - HCI

17a Y = -NH2

17b Y = -OH

FH3

F- FH3

F-

1aa X = -NH-CO-

CH3

l a b -0-co- CH,

1 ac -NH-CO-CH2-

18d -0-CO-CH2-

I Be -NH-CH2-

active moieties we prepared antioxidants and light stabilizers by end-capping of living polybutadiene (7) with appropriate stabilizing agents and subsequent hydrogenation. Thus, the antioxidant 16 was obtained with 3-(3,5-di-tert- butyl-4-hydroxypheny1)propionic acid methyl ester (Scheme 6) and the light stabilizers 19a and 19 b with N-methyl-2,2,6,6-tetramethyl-piperidin-4-one (MTP) and 2,2,6,6-tetramethylpiperidin-4-one as end-capping reagents (Scheme 8). Interestingly, the end-capping reagents could be applicated without protecting groups due to sterical hindrance of the HO- and HN-group, respectively.

MTP was obtained by a new synthetic method shown in Scheme 9 in an overall yield of 85% compared to 60% of the literature procedure20.

213


Scheme 8

\ 19a.b

19a R’ = CH3

19b H

co

OH

20

Scheme 9

1. +HCHO

H P + H O / \ / O ~ - H20 H+ H N 3 1 - MTP

The telechelic light stabilizer 19a was esterified with 12 to yield the polyfunctional telechelic additive 20 containing 20 wt.-To light stabilizer groups and 24 wt.-To antioxidant (Scheme 8).

Esterification of the oligomeric diol 9b with 4-methoxy cinnamic acid chloride, 4-N,N-dimethylaminobenzoic acid chloride, and 4-(2H- naphtho-[ 1,2-d]-triazol-2-yI)stiIbene-4’-carboxylic acid chloride yielded the telechelic UV-absorbers 21, 22 and the optical brightener 23 (Scheme 10).

214


Scheme 10

R-CO-O-(CH,),{ P j-(CH,hO-CO-R

9b + CIOC-CH=CH 21 - 23

All

21

22

23

elechelic I abilizers exhibited good compatibility with commercial polyolefines. The stabilizers were tested in polypropylene films by a standard weathering method (Xenotest) and aging (oven) tests using commercial low- molecular stabilizers as references. The tests demonstrated similar efficiencies of the reference stabilizers and the telechelics H a , b, 19b and 20 whereas 18e showed even higher light stabilizing activities. The efficiency of the antioxidant 14 was nearly equal to the low-molecular standard, although the telechelic antioxidant contains only about half the amount of active phenolic groups. Possibly the efficiencies of these telechelic additives can be further improved by optimization of the chain length of the oligomers.

Experimental

Tetrahydrofuran (THF) was pre-dried by common methods. After addition of sodium (5 g) and benzophenone (20 g) to THF (1 l), it was refluxed to generate a

21 5


permanent blue colour and then distilled under purified nitrogen. Naphthalene was purified by sublimation and dried over P,Os. Sodium metal was washed in petrol ether and pressed into wire before use. Azoisobutyronitrile (2a) was recrystallized twice from methanol and dried under reduced pressure at 20 "C. 2,2,6,6-Tetramethylpiper- idin-4-one was recrystallized twice from diethylether and dried over P20,.

Azoisobutyric acid dimethyl ester (2 b)2', 4-(2 H-naphtho[ t,2-d]triazol-2-yl)stil- bene-4'-carboxylic acid22 and 4-dimethylaminobenzoyl chloride23 were prepared by known methods. 3-(3,5-Di-tert-butyl-4-hydroxyphenyl)propionic acid and 4-methoxycinnamic acid were converted to the acid chlorides with SOCl,.

Preparation of telechelic polyolefines

Synthesis of 5:

A dry, thick-sided pressure glass tube was filled under nitrogen with 2a (4.0 g, 24.4 mmol) and l(8.1 g, 150 mmol) at -78 "C, fused and heated to 70°C for 17 h on a dark place. After cooling to 20 "C the tube was rinsed with methyl cyclohexane. The solution was mixed with an equal volume of acetic anhydride and after addition of Pdkarbon catalyst (0.5 g), the mixture was hydrogenated for 5 h at 20 "C (3 bar H2). The solvents were evaporated, the residue dissolved in THF, filtered from the catalyst, and the telechelic dinitril 4a was precipitated twice into THF/methanol. Yield: 5.4 g 4a (45070), MW (calcd.) 480, MW (osm.) 851.

CS&, 14N2 (851 .58) Calcd. C 83.22 H 13.49 N 3.29 Found C 83.60 H 12.55 N 3.47

(The calculation is based on MW (osm.) which was determined with a tolerance of 6- 10%).

Dinitrile 4a (20 g, 24 mmol) was dissolved in THF (200 ml) and a solution of LiAlH, (7.2 g, 190 mmol) was added with stirring. The solid, white complex was treated with water (20 ml) and 10 M NaOH (30 ml). After filtration the solvent was removed under reduced pressure. Yield: 19.0 g 5 (95%), MW 876 (by titration of the end groups with 0.1 M HCl).

IR (cm-I): 800, 1060, 1620, 2830-2940, 3300-3450.

Synthesis of 6:

The telechelic diester 4b was prepared from 2b (5.6 g, 24.3 mmol) and 1 (8.1 g, 150 mmol) in the same way as compound 4a; it was precipitated three times into THF/methanol.

Yield: 7.1 g 4b (54%), MW (osm.) - 1 OOO.

216


4 b (1 9 g) was refluxed in dry ethanol (1 50 ml) with stirring and sodium metal (6 g) was added in small pieces. After refluxing for 1 h water (100 ml) was added and the mixture was acidified with HCI. The dicarboxylic acid 6 was obtained by extraction with diethyl ether. Yield: 11 g 6 (58%), MW calcd. 520, MW (titr.) 986 (by titration of end groups with 0.1 M methanolic NaOH).

IR (cm-I): 950, 1200, 1300, 1710, 2400-3600.

Preparation of living polybutadiene (7):

All glass ware was rigorously dried by evacuation, heating and filling with pure nitrogen. This procedure was repeated three times before use. Sodium naphthalene was prepared in a calibrated dropping funnel by shaking a mixture of naphthalene (17 g), shiny sodium metal ( 5 g) and THF (100 ml) for 3 h. The content of sodium naphthalene was determined by treating a sample with methanol and subsequent acidimetric titration.

60 ml of THF were distilled into a calibrated dropping funnel. After cooling to --7O"C, 27.8 ml of 1 (ca. 18.9 g, 350 mmol) were condensed into the funnel. 100 ml of THF were freshly distilled into a round bottom five-necked flask equipped with nitrogen inlet/outlet, two dropping funnels containing the solutions of sodium naphthalene and butadiene, thermometer and magnetic stirrer. Some drops of the sodium naphthalene solution were introduced to generate a permanent green colour and then a volume containing 0.1 11 mol initiator was added. The solution was cooled to - 15 "C and the butadiene solution was added at a rate keeping the temperature at - 10 to - 15 "C. The light-brown solution of living polybutadiene (7) was cooled to -- 70 "C and stirred for 1 h. From the ratio of monomer to initiator a theoretical degree of polymerization of 6.3 (MW 352) is calculated.

Synthesis of 8:

Ca. 25 g of powdered dry ice were added to the solution of 7 yielding a white mixture of sodium salts. The solvent was evaporated and the residue was stirred in a mixture of water (100 ml) and methanol (30 ml). After filtration from the precipitated naphthalene the solution was hydrogenated for 5 h in an autoclave at 80- 90 "C (30 bar H,) with 5 g of Raney-Ni as catalyst. The catalyst was filtered and the solvents were removed by distillation. The residue was acidified with HCI and dissolved in diethyl ether. The organic phase was washed several times with water and dried over Na,SO,. Evaporation of the solvent yielded 8 as a yellow oil. The molecular weight was determined by titration of a sample in THF with 0.1 M NaOH as well as by vapour phase osmometry. Yield: 20 g 8 (84070), MW (titr.) 679 (by titration of the end groups with 0.1 M methanolic NaOH), MW (osm.) 681.

217


C,H,,O, (679.17) Calcd. C 77.81 H 12.76 0 9.42 Found C 78.80 H 10.66 0 10.52

(the calculation is based on MW (osm.) which was determined with a tolerance of 6- 10%).

IR (cm-I): 950, 1200, 1300, 1710, 2400-3400.

Preparation of 9a, b:

20 g of ethylene oxide were added to the solution of 7 and stirred for 1 h. After acidification with conc. HCl the mixture was filtered and hydrogenated for 8 h at 20 "C (4 bar H2) with 1 g of 5% Pdkarbon as catalyst. The catalyst was filtered and the naphthalene was removed by column chromatography on silica gel with methanol/ benzene (1 :9, v/v) as eluent. The solvent was removed by distillation and 9a was obtained as a colourless oil.

Yield: 17 g 9a (71.5%), MW (osm.) 512, MW (elemental anal.) 542.

IR (cm-'): 950, 1 200, 1 300, 3 150-3600. 9b was obtained by an analogous procedure using 0.03 mol initiator. Yield: 17.8 g

9b MW (osm.) 1480, MW (elemental anal.) 1520.

Preparation of 10 a - d:

20 g of chloroacetaldehyde dimethyl acetal were added quickly to the solution 7. The temperature was raised to 0 "C and the mixture became colourless. After stirring for 1 h at 20 "C the solvent was removed under reduced pressure and the residue was treated with methanol (200 ml) and distilled again. The residue was dissolved in 100 ml of methanol and 2 drops of 2 N HCI were added. The phases were separated by centrifugation and the residue was stirred in THE After filtration from NaCl the solvent was removed under reduced pressure yielding 17.1 g (60%) acetal-end-capped polybutadiene as a yellow oil. This product was hydrogenated in methylcyclohexane/ acetic anhydride (1 : 1) for 10 h at 20°C and 4 bar H, using 1 g of 5% Pdkarbon as catalyst. The catalyst was filtered off and after removal of the solvent 10a was obtained as a colourless oil. Yield: 17.5 g 10a (95.4%).

IR (cm-I): 1050, 1120. For splitting of the acetal groups, 30 g of 10a were refluxed for 1 h in a mixture of

THF (100 ml) and 3 M HCI (10 ml). The solvent was removed by distillation, the residue was dissolved in diethyl ether. The organic phase was washed with NaHCO,

218


solution and water, dried over Na,SO, and the solvent was distilled. Yield: 25.9 g 10b (99.6%) MW (calcd.) 426, MW (osm.) 600.

C,,H,,O, (591.06) Calcd. C 81.29 H 13.30 0 5.41 Found C 82.41 H 12.31 0 5.12


IR (cm-I): 1730, 2700. Another oligomeric dialdehyde (10d) with MW (osm.) 775 was prepared by the same

procedure from a living polybutadiene based on 350 mmol 1 and 70 mmol sodium naphthalene.

Synthesis of 11 a:

12.7 g of 8 were refluxed with 50 ml of SOCI, for 2 h. The excess SOCI, was distilled off and the residue was dissolved in benzene (50 ml) and distilled again. The acid chloride was dissolved in benzene (200 ml) and treated with gaseous ammonia. The solvent was removed under reduced pressure and the residue was dissolved in diethyl ether. Filtration from the ammonium chloride and distillation of the solvent yielded 12.5 g (98%) telechelic diamide, which was refluxed with SOCI,. After removal of the excess SOCI, and precipitation into THF/methanol 10.2 g (86%) of the dinitrile 8a were obtained.

For the reduction of the nitrile groups, a solution of 3.5 g LiAlH, in diethyl ether was added to a solution of 8a (14.4 g) in diethyl ether (100 ml) with stirring. The resulting solid product was treated successively with water (5 ml), 5 M NaOH (10 ml) and water (5 ml). The solids were filtered and the solvent was removed under reduced pressure yielding a yellow oil. Yield: 10.9 g l l a (75%), MW - 650 (calculated from elemental analysis).

C,H,,N, (649.24) Calcd. N 4.04 Found N 3.70

IR (cm-I): 1600, 3 100-3 500.

Synthesis of 11 b:

A mixture of 1Oc (3.15 g, MW 775, 4.1 mmol), Raney-Ni (2 g) and THF (500 ml) was stirred with gaseous ammonia in an autoclave for 1 h. Then the mixture was hydrogenated for 5 h at 130°C and 100 bar H,. The catalyst was filtered and the solvent was removed under reduced pressure. The residue was dissolved in 100 ml

219


diethyl ether and after addition of a solution of LiAlH, (0.5 g) in diethyl ether (50 ml) the reaction mixture was refluxed for 1 h. 3 ml of water were added and the precipitate was filtered. The residual yellow oil was dried under reduced pressure.

(the aldehyde groups were reduced partly to alcohol groups). Yield: 2.4 g l l b ; calcd. N 3.61, found N 2.00

Preparation of telechelic additives

Synthesis of 13:

A solution of 12 (13.4 g, 45.3 mmol) in benzene (100 ml) was added slowly to a stirred mixture of 5 (19 g, 22.3 mmol) and Na,CO, (6 g). After refluxing for 1 h the inorganic salts were filtered and the solvent was removed under reduced pressure. The residue was dissolved in THF and precipitated twice into methanol. Yield: 26.5 g 13 (86.5 070).

C,,H,,,N,O, (1 380.40) Calcd. C 80.92 H 12.41 N 2.03 Found C 79.24 H 11.76 N 2.17


IR (cm-I): 1 550, 1650, 1730, 3200-3500, 3640.

Synthesis of 14:

A solution of 12 (12.3 g, 41 mmol) in benzene (100 ml) was added to a stirred mixture of l l a (10.5 g, 16.2 mmol), benzene (80 ml) and NaHCO, (5 g). After refluxing for 1 h the inorganic salts were filtered, the solvent was removed by distillation. The residue was dissolved in ether and the organic phase was washed with 2 M NaOH and water. After drying over Na,SO,, stirring with carbon black and filtration the solvent was removed under reduced pressure. Yield: 19 g 14 (94%)

C68H,28N204 (1 037.80) Calcd. C 78.50 N 2.70 0 6.77 Found C 78.16 N2.18 0 7.18

(the calculation is based on the MW of the diamine). IR (cm-I): 1550, 1650, 1730, 3200-3500, 3640.

Synthesis of 15:

A solution of 12 (1 3 g, 41 mmol) in benzene (50 ml) was added to a stirred mixture of 9 a (1 1.17 g, 21.8 mmol), benzene (100 ml) and NaHCO, (5 g). After refluxing for

220


1 h the mixture was filtered and the solvent was distilled. The residue was dissolved in diethyl ether and the organic phase was washed several times with 0.5 M NaOH, 2 M HCI and finally with 2 M NaHCO,. The product was isolated by removal of the organic solvent. Yield: 22.3 g 15 (99yo).

Elemental analysis:

C6,H,,806 (1031.69) Calcd. C 79.17 H 11.53 0 9.30 Found C 79.78 H 10.96 0 9.46

IR (cm-I): 1740, 3640.

Synthesis of 16:

3-(3,5-Di-tert-butyl-4-hydroxyphenyl)propionic acid methyl ester (25 g, 86 mmol) was added to a solution of 7 (28 g, MW (calcd.) 702, 39.9 mmol) at -78°C. The temperature rises to - 30 "C. The yellow solution was stirred for 1 h at 20 "C, the THF was removed under reduced pressure and the residue was precipitated twice into THF/methanol. The product was hydrogenated in methylcyclohexane/acetic anhydride for 4 h at 20°C (4 bar H,) with Pdkarbon catalyst. After filtration 16 was isolated as a yellow oil by precipitation into methanol.

Yield: 25 g 16 (56%), MW (osm.) 1869, MW (calculated from elemental analysis) 2766, corresponding to an average functionality of 1.35.

C,96H34504 (2765.92) Calcd. C 85.1 1 H 12.57 0 2.31 Found C 85.47 H 12.62 0 2.32

IR (cm-I): 1710, 3650.

Synthesis of 18a, b:

13 g (13.2 mmol) of 6 were refluxed with 50 ml of SOCI, for 20 min. The excess SOCI, was removed under reduced pressure and the acid chloride of 6 was dissolved in benzene (100 ml) and added slowly to a solution of 17a (8.0 g, 51.3 mmol) in 50 ml of benzene. The reaction mixture was refluxed for 1 h, the precipitated hydrochloride was filtered and the solvent was evaporated. The residue was dissolved in diethyl ether and washed several times with water. The organic phase was dried over Na,S04 and the product was isolated as a brown oil by evaporation of the solvent. Yield: 13 g 18a (78%). The product absorbs CO, from the air.

22 1


C,,H,66N,O,* 1.05 ' 2 0 2 (1 310.49) Calcd. c 77.95 H 12.77 N 4.28 0 5.01 Found C 77.94 H 12.74 N 4.14 0 5.18

IR (cm-'): 1550, 1650, 1730, 3 300. 18b was prepared by the same procedure by esterification of 6 with 17b.

Synthesis of 18c:

20 g (29.4 mmol) of 8 were refluxed with 100 ml of SOCI, for 20 min. The excess SOCI, was removed under reduced pressure and the acid chloride of 8 was dissolved in benzene (100 ml) and added slowly to a solution of 17a (20.3 g, 130 mmol) in 100 ml of benzene. The reaction mixture was refluxed for 1 h, the precipitated hydrochloride was filtered off and the solvent was evaporated. The residue was dissolved in diethyl ether and shaken with 2 M HCI. The hydrochloride of the telechelic separates and the organic phase was washed with 2 M NaOH and twice with water. The solution was dried over Na,SO,, stirred with carbon black and the product was isolated by evaporation of the solvent. Yield: 25 g 18c (88%).

C,,H,,,N,O, (969.70) Calcd. C 77.92 H 12.87 N 5.86 Found C 78.37 H 12.44 N 5.53

IR (cm-I): 1550, 1650, 1730, 3 300.

18d was prepared by the same procedure using 8 (20 g, 29.4 mmol) and 17b (20.4 g, 130 mmol). Yield: 24.5 g 18d (87.5%).

C6,H,,N,0, (957.66) Calcd. C 77.76 H 12.53 N 2.93 Found C 77.63 H 12.17 N 2.65

IR (cm-I): 1740.

Synthesis of 18e:

A solution of 10a (24.5 g, 41 mmol) and 17a (25 g, 160 mmol) in THF (800 ml) was hydrogenated with Raney-Ni catalyst (5 g) in an autoclave at 125 "C and 100 bar H, for 4 h. The solution was filtered, the THF was evaporated and the residue was distilled with benzene to remove water. For complete reduction, the residue was dissolved in THF (50 ml) and a solution of LiAIH, (2.5 g) in THF (50 ml) was added. After refluxing for 30 min the solution was treated successively with water (2.5 ml), 5 M NaOH (8.5 ml) and water (2.5 ml). The precipitate was filtered, the solvent was evaporated, the residue was dissolved in diethyl ether and after several washings with water the product was isolated as a yellow oil. Yield: 29.7 g (82.7%) 18e.

222


C5gH[ IsN, (871 .61) Calcd. N 6.43 Found N 5.65

From this analysis 88% conversion of the end groups is calculated which corresponds to about 76% di- and 24% monosubstituted product.

Synthesis of 19a:

N-methyl-2,2,6,6-tetramethylpiperidin-4-one (20.6 g, 122 mmol) was added to a solution of 7 (28 g, MW (calcd.) 702, 39.9 mmol) at -78°C. The temperature increased to - 30 "C. The yellow solution was stirred for 1 h at 20 "C and THF was removed under reduced pressure. The residue was treated with 2 M HCl (200 ml) and diethyl ether. The organic phase was separated and diluted with diethyl ether to precipitate the polymeric hydrochloride. The hydrochloride was filtered, 2 M NaOH was added and the aqueous phase was extracted several times with diethyl ether. The organic phase was dried and the solvent evaporated. The residue was dissolved in a mixture of THF (200 ml) and methanol (500 ml) and hydrogenated in an autoclave with 2.5 g of Raney-Ni catalyst at 75°C and 25 bar H, for 6 h. The catalyst was filtered off, the solution concentrated and the product was precipitated twice from THF in methanol. Yield: 20 g 19a (53%).

C,,H,,,N,O, (1 055.93) Calcd. C 80.78 N 2.65 0 3.03 Found C 81.07 N 2.65 0 2.85

Synthesis of 19 b:

2,2,6,6-Tetramethylpiperidin-4-one (24.6 g, 174 mmol) was added to a solution of 7 (28 g, MW (calcd.) 702,39.9 mmol) at -78 "C. The temperature increased to -25 "C. The yellow solution was stirred for 1 h at 20 "C and THF was removed under reduced pressure. The residue was dissolved in petrol ether and shaken five times with 2 N HCl. The polymer separated between the organic and aqueous phase was treated with 2 N NaOH and extracted with diethyl ether. The organic phase was dried and the solvent evaporated. Yield: 20 g, with light stabilizing end groups (58%) MW (titr.) - 928. C,,H,,,N,O, (917.59) Calcd. C 81.16 H 12.30 N 3.05

Found C 81.16 H 12.13 N 3.32

The residue was dissolved in methanol and hydrogenated in an autoclave with 2.5 g of Raney-Ni catalyst at 80 "C and 25 bar H, for 8 h. The catalyst was filtered off, the solution concentrated and the product was precipitated twice from THF in methanol. Yield: 20 g 19 b.

223


Synthesis of 20:

A solution of 12 (10.1 g 34 mmol) in benzene (50 ml) was dropped to a stirred mixture of 19a (15 g, 14 mmol), benzene (100 ml) and Na,CO, (3.7 g). After refluxing for 1 h the salts were filtered and the solvent evaporated. The residue was dissolved in diethyl ether and shaken several times with 2 M NaOH and finally with water. The product was isolated from the organic phase as a yellow oil. Yield: 15 g 20 (67%).

C,,&,&06 (1 576.7) Calcd. c 80.67 H 12.17 N 1.76 Found C 80.12 H 12.25 N 2.03

Synthesis of 21:

4-Dimethylaminobenzoylchloride (1.15 g, 6 mmol) was added in two portions to a solution of 9 b (4 g) in pyridine (1 00 ml) at - 8 "C. The mixture was stirred at 80 "C for 20 h. The solvent was evaporated and the residue was precipitated into water. The product was purified by precipitation from benzene/methanol. Yield: 2.25 g 21 (42Yo), 0.65% N (37% conversion of the HO-groups).

IR (cm-I): 1 100, 1 170, 1280, 1370, 1450, 1520, 1600, 1720, 2840-2980, 3057.

Synthesis of 22:

4-Methoxycinnamic acid chloride (0.93 g, 4.7 mmol) was added to a solution of 9 b (3 g) in pyridine (50 ml). The mixture was stirred at 20°C for 20 h. Then benzene (50 ml) and water (200 ml) were added. The aqueous phase was separated and extracted twice with benzene. The combined organic phases were shaken with dilute HCI (2070) and water. The solvent was evaporated and the residue was precipitated from benzene/acetonitrile. Yield: 1.80 g 22 (50%).

Content of UV-absorbing end groups: 10% (by UV-photometry). IR (cm-I): 1 170, 1270, 1380, 1470, 1510, 1605, 1640, 1730, 2840-2980, 3060.

Synthesis of 23:

4-(2H-naphtho[ 1,2-d]triazol-2-yl)stilben-4'-carboxylic acid chloride (1.93 g, 4.71 mmol) was added to a solution of 9b (3 g) in pyridine (60 ml) and stirred at 50 "C for 24 h. The mixture was poured into water (600 ml) and stirred for 1 h. The yellow precipitate was filtered and after drying it was precipitated with benzene/acetonitrile. Yield: 1.47 g 23 (58%), N 2.18%; content of UV-absorbing end groups: 21.3%.

IR (cm-I): 1 110, 1 170, 1280, 1380, 1460, 1515, 1600, 1720, 2840-2980, 3060.

224


Synthesis of N-methyl-2,2,6,6-tetramethylpiperidin-4-one (MTP):

2,2,6,6-Tetramethylpiperidin-4-one (45 g, 0.29 mol) was converted to its hydrochloride by treatment with gaseous HCI in diethyl ether. The hydrochloride was refluxed with ethylene glycol (18.5 g, 0.30 mol) and 4-toluenesulfonic acid (0.7 g) in 200 ml of benzene for 15 h, removing water by azeotropic destillation. The mixture was filtered and 2 M NaOH (200 ml) was added. The ethylene acetal was isolated by extraction with diethyl ether, yield: 54.5 g (94%). The acetal was dissolved in formaline (37%) and stirred for 2 h at reflux temperature, while the N-methyl derivative separates. After addition of 2 M NaOH 25.8 g (96%) of N-methyl-2,2,6,6-tetramethylpiperidin-4-one ethylene acetal was obtained by extraction with diethyl ether, drying with KOH and removal of the solvent. The acetal was refluxed in 150 ml of 2 M HCl for 3 h. After cooling sufficient 2 M NaOH was added to adjust the mixture alkaline and MTP was isolated by extraction with diethyl ether, removal of the solvent and distillation. Yield: 18.9 g (89%) MTP, b. p. 46 "C (6.7 Pa).

CIoH,,NO (1 69.27) Calcd. C 70.96 H 11.31 N 8.27 Found C 71.24 H 11.42 N 8.07

I L. Brauer, H. Gruber, G. Greber, Angew. Makromol. Chem. 182 (1990) 165 * D. Bailey, 0. Vogl, J. Macromol. Sci., Rev. Macromol. Chem. Phys. C14 (1976) 267

J. Pospiiil, Angew. Makromol. Chem. 158/159 (1988) 221 J. Pospiiil, Adv. Polym. Sci. 101 (1991) 66 0. Vogl, Makromol. Chem. Suppl. 7 (1984) 1 0. Vogl, A. C. Albertsson, Z. Jovanovic, ACS Symp. Ser. 280 (1985) 197 0. Vogl, A. C. Albertsson, Z. Jovanovic, Polymer 26 (1984) 1288 P. Grosso, 0. Vogl, J. Macromol. Sci., Chem. A23 (1986) 1041 T. Miyazawa, T. Endo, M. Okawara, J. Polym. Sci., Polym. Chem. Ed. 23 (1985) 1527

l o W. Dickstein, 0. Vogl, J. Macromol. Sci., Chem. A22 (1985) 387 D. Munteanu, M. Mracec, I. Tincul, C. Csunderlik, Polym. Bull. (Berlin) 13 (1985) 77 D. Munteanu, in: Developments in polymer stabilization, G. Scott (Ed.), Elsevier, London 1987, vol. 8, p. 209 U.S. 4704470 (1986), Dow Chemical Co., Inv.: M. R. Johnson, C.A. 108 (1988) 76405e N. A. Nguyen, E. Marechal, J. Macromol. Sci., Rev. Macromol. Chem. Phys. C28 (1988) 187 U.S. 4377666 (1983), Phillips Petroleum Co., Inv.: R. C. Farrar, C.A. 98 (1983) 2 16948m Japan 88218,746 (1988), Yokohama Rubber Co., Invs.: K. Kayama, Y. Kikuchi, T. Muraki, C.A. 110 (1989) 116459a

' *

I'

l 3

l 4

I s

l 6

225


" Y. Minoura, Y. Yamamoto, T. Sako, S. Oinoto, K. Satoyoshi, Nippon Gomu Kyokaishi 53 (1980) 625, 631

l 8 U. S. 4522990 (1985), du Pont de Nemours, Inv.: G. D. Andrews, C.A. 103 (1985) 10544211

l 9 P. M. Gomez, H. H. Neidlinger, Polym. Prepr. (Am. Chem. SOC., Div. Polym. Chem.) 28(1) (1 987) 209

2o L. Orthner, Justus Liebigs Ann. Chem. 456 (1927) 251 21 J. Thiele, K. Heuser, Justus Liebigs Ann. Chem. 290 (1896) 1 22 Ger. 2539537 (1976), Ciba Geigy AG, Invs.: H. R. Meyer, R. Zweidler, C.A. 85

(1 976) 48287f 23 J. Decombe, Bull. SOC. Chim. Fr. 6 (1951) 456

226

new polymer additives, 3. telechelic additives for polyolefins

Documents