CA2133802A1 - Process for the reduction of sulfoxide groups in polymers - Google Patents

Abstract

Abstract The invention relates to a process for the preparation of polymer sulfides, which comprises treating compounds containing sulfoxide linking groups of the formula (I) -[(Ar1)n-X]n-[(Ar2)i-Y)]j-[(Ar3)k-Z)]l-[(Ar4]o-W)]p- (I) in which the symbols and indices have the following meaning:

Ar1, Ar2, Ar3 and Ar4 are identical or different arylene systems having 6 to 18 carbon atoms, W, X, Y and Z are identical or different -SO2-, -S-, -SO-, -CO, -O-, -CO2-, alkylene or alkylidene groups having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, where at least one linking group W, X, Y or Z must be an -SO- group, n, m, i, j, k, l, o and p are, identically or differently, 0 or an integer 1, 2, 3 or 4, where their total must be at least 2, a) thermally or b) in the presence of active hydrogen or c) photochemically and reducing to give the corresponding sulfides.

Description

HOECHST ARTIENGESELLSCHAFT ~OE 93/F 311 Dr KX/PP

Doscription Procese for tho reduction of ~ulfoxlde group~ ln polymer~ ~ ;

The invention relutes to the soleot~ve photochQmical, chemical or thermal reduction of ~ulfoxlde linking group~
to thioether~ in polymer compound~

It is known that organic sulfoxides can be reduc-d by ~-homogeneou~ catalytlc hydrogenatlons, g w~th Pd/Activated carbon (R Ogura t al , Synthosi~
June 1975, p 385) However, this method lo unsultable ~ ;
for heterogeneous condltions, i o in Euspensio~s, as the activated carbon can only be incomplotely r moved from the de~ir-d product A t-chnlqiue of thi~ type ca~
therefore not be usod in the ca~e of vory chemlcal~
15 re~i~tant polymers, such ao p-polyph-nylene sulfoxide In ;~
addition, genoral transforabllity of already-known -~
reactlons to polymers 18 not possiblo It wa~ thorofore an ob~oct of the invontion to devolop ~i proce~ wlth whlch ~ulfoxldo llnking groupo can be 20 roact-d to giv- tho corro~pond~ng th~oethorc ovon ln ;~;
chomlcally re~l~tant polym-r~

Tho invontion thus relatoe tos ~, A proa-~e for tho propar-tlon of polymer ~ulfldo~, whlch comprleo~ tr-atlng compounds contalnlng eulfoxld- llnking 0roup~ of the formula I

X) 1~ Y) 1~- t ~ Z) 1,- 1 lAs~) o~W) 1 ln whlch th~ ~ymbole and lndlcos have the followlng moanings ~ ~
", Ar', Ars, Ar3 and Ar~ are ldentical or differont aryl-n~
.~
. .
, ,': '~ ,';',' ' s o ~
.

~y~tem~ having 6 to 18 carbon atoms, W, X, Y and Z aro ldentlcal or difforont -SO~ S-, -SO-, -CO, -O-, -CO~-, al~ylone or alkyl$dene groups having 1 to 6 carbon atoms, preforably l to 4 carbon atoms, where at loast ono lln~lng group W, X, Y or Z must be an -SO- group, n, m, i, ~, ~, l, o and p aro, ld~ntloally or diffor-ntly, 0 or an intogor 1, 2, 3 or 4, whoro t~olr totnl must be at lea~t 2, , '-''," ~
a) thormally or b) with activo hydrogon or -~
c) photochomically and reduclng to glvo tho corrosponding sulfldo~ ;

Compounds of tho formula I proferred are polyaryl-ne ~ ;
15 sulfoxidss and/or polyarylene oulfide/~ulfoxidos con- -taining the recurring unit of the formula (II), whose proparation process l~ descrlbod, e g ln th- Patent ~ -Application~ P 43 14 736 4 and P 43 14 735 6 ll (II) -(Ar5-S)a-~Ar6-S-)b , ~, Th- ratlo of oxyg-n to ~ulfur ln the compound of the formula (II) l~ sl and ~ 0, the total of a and b alwayc ;~
b-lng 1, ~uch that a 1~ 0 wh-n b 1~ 1 In formula (II), ~ ~ ;
Ar~ and Ar' are, ldontlcally or differontly, ~aphthylon-, bl- or trlphenyl-n- or ph-nyl~ne Partlcularly pr-f-rr-d compound- r- tho!o contalning r-currlng unit~ of th- formula (III) ll (III) ~;
-~C6H4-S)a-~C6H4-S-)b wh-r- th- oxyg~ns~ulfur ratio nd tho doflnltlon of a and b ar~ a~ indlcat-d abovo .,~
In gonoral, polymors are suitablo for tho inv~ntion wh~ch ~'''' have a ~ea~ molocular weight of 4000 to 200,000 g/mol, preferably of 10,000 to 150,000 g~mol, in particular 25,000 to 100,000 g/mol, deter~lned by aP

Accordlng to the invention, the ~ulfoxlde group~ of the polym~r~ can bs reduced by activ- hydrogen in diff-r-nt media This can bs carried out ~ith-r in a su~p-n~ion or diroctly The temperature and duratlon in thls caae depend on the activation of the hydrogen a~d the thickne~s of the layer to be reduced In the case of hydrog~nations in Bronst-d acid~, th~
hydrogen can be formed by the additlon of ba~- m-tal~
having an electrod~ potential which is b~low that of hydrogen Customary metals omployed for this purpo~o in induetry are lron or zinc, whlch are to bo mentloned here by way of example R-du~tlon 1~ carr~od out at t-mperature~ o$ 30C to 120C, prof~r~ly 50C to 100C
and particularly pref~rably at 50C to 90C D~p-ndlng on tho thlckness of the part~ to bo roducod, the r-act~on time is betw-~n 1 hour and 24 hour~, pr-forably botw-en 2 hours and 20 hour~ and particularly prof-rably b~tweon 4 and 20 hour~

A¢cordlng to th- inv-ntion, th- dlr-ct r-actiono with aatlv- hydrog-n can al~o b- carri-d out in an autoclav-Tn thi~ ca~o, th~ polym-r lo react~d in a hydrog-n atmo~ph~r- at pr-ssur-~ of 10 bar to 300 bar, pref-rably 20 bar to 250 bar and particularly pr-ferably 30 bar to 200 bar, nd at tomp-ratura~ of 60C to 220C, pr-f-rably 80C to 200C and~particularly prefer bly 100C to 200C
Dep-ndlng on th- thlckn-~ and morphology of th- part~ to b- r-duc-d, th- r-actlo~ tlm- i- b-tw -n 1 and 36 hour~, pr-f~rably b-twe-n 4 and 30 hour- and ~articularly pref-rably b-tw-en 8 and 24 hour~

Su~p-n~ion hydrog-nations in ~aturated aliphatic alcohol~
havlng a chain l-ngth of Cl to C5 and/or Jaturat-d allphatlc carboxylic aclds havlng a chaln length of Cl to ;; `' ''," ~

,' ~, ,'~,''~

C5 can additionally be carried out ln an autoclavo Thi~
takes place in a hydrogen atmo~phoro at preesuroe of lO
to 300 bar, preforably 20 bar to 250 bar and p~rticul~rly preferably 30 to 200 bar, and at tomperaturee of 40C to 180C, profer~bly 60C to 160C

Anothor poeeibillty for tho activatlon of hydrogon i~ the addition of a catalyet which di~aolves in nonoxidizing acide, e g Raney nlc~el Depondlng on the thiokc~ of the part~ to bo roduced, the roaction t~me le betwoon 1 hour and 24 houre, proforably botw~on 2 hour~ ~nd 20 houre, particularly prefor~bly botweon 4 and 20 hour~

The reaction can al~o bo carrlod out photochomically ln cuetomary vacuum unit~ which aro equipp-d with en~rgy eourcee in the en~rgy range betweon 0 5 and l,OOO,OOO,Q00 oV, preforably 0 5 - 100,000,000 oV, or partlcularly preferably 0 5 - 50,000,000 oV The radlation den~ltl~
of the unite can vary ln tho range from 0 1 ~W/c~'o to 1000 GW/cm~s Tho radiatlon sourcee employ-d can be photon eourc~ uch ae sy~chrotron radiation or UV
l~mps, or ol-ctron boam source~ According to th-invontion, the temperaturo 18 ln tho rang- from 4 ~ to 600 R, proferably from 270 to 550 ~ and partlcularly prof-rably 275 R to 520 ~ Dopondlng on tho radlation don~lty, the trcatmont tlmo 1~ ln tho rang- from 30 ~ocond~ to 48 hour~, pr-ferably from 1 mlnuto to 36 hour~ and particularly preferably from 1 mlnut- to 24 houro Th- r-ductlon can alco b- carri-d out th~rmally, o g in cu~tomary vacuum ovon- ln a pro--uro rang- botw-on 10 bar and 101~ mbar, prof-rably fro~ 1 bar to 10' mbar ~nd partlcularly preforably from 1 bar to 10' mbar, and ln tho tomp-ratur- rang- botw~on 100 and 600C, prof-rably 120 to 500C and partlcularly proforably 120C to 400C
R-ductlon ln alr or undor a protoctlv~ ga~ atmo~phor-, e g Nl, O~ or a raro gas atmo~phere, i~ al~o po~siblo ln tho temp-raturo and pro~uro range~ lndlcated Dopo~dlng G3 ~
_ 5 _ on the preYsuro and temperature, the treatment timo i~ in the rangs from 1 minute to 100 hour~, pref-rably from 1 minute to 72 hours and partlcularly pro$orably from 1 minuto to 48 hour~

Tho polymors can bo omployed as powdor~, flber~ or molded articles Tho dopth of the rsduction i8 ln thl~ caso ~trongly depondent on tho morphology, tho erystallinlty, t mperaturo, troatment time and pre~sur- The powdor~
have commercially available particlQ 8~ ze~, granulo~ al~o being utilizable If the polymers ar- u~ed a~ flbor~
th-se are employod as staple fiber~, neodlo folt, non~
wovon material, slivor or fabric Films or film ~nlpplngs can also be employod In the reduction of the polyarylenes employ~d, the polymere aro roact-d to tho stage of the corro~ponding polyarylene ~ulfide Ih- polyaryl-ne sulfidos pr-parod in this way can be ~mployod for any appllcation ~nown to date, e g for the productlon of mold-d articlo~ by ln~-ctlon molding The polyaryl-ne ~ulfldo can be omployed in uncut form for tho productlon of moldod artlclo~ How-vor, tho addltion of customary fillor~, ouch a~ chalk, talc, olay, mica and/or fibrou~ r-lnforclng agent~, such a~ gla~ and carbon ~lb-r~, whi~k-ro, and further eu~tomary additiv-s and proc-~ing auxlliario~, g lubr~cant~, parting agent~, antioxidant- and UV ~tabiliz-r~ 1~ al~o po~lblo .:
Flb-r~ and ~llm~ ean additionally b- produced Th- fil!ms ean b- etretch-d uniaxially or biaxi-lly, tho fib-r~ ean b- un~troteh-d or tr-tehod ~urthormoro, tho polyarylone sulfides form-d can be sm~loy-d in accordanc- with G-rman Pat-nt Application P 43 14 734 a~ ~ilt-r matorial for ozono or in accordanc-with Patont Applieation P 43 28 405 7-27 a~ f~lt-r material for nltrog0n oxides, whor-by they ar- react-d to . ~ ,, ~ ~, .", .. .

~' ' ~ ,~.

~ ~3~.9`t3~

give the corre~ponding eulfoxide~ Thie meane that tho proces~ according to the inventlon 1~ also utilizable for the recycling of f~lter m torial~ of thie typo ;

Examples S 1 ) Preparatlon of polyphonylono 0ulfoxido accordin~ to Gorman Patent Applicatlon P 43 14 736 4 2 ) Chemical reduction 2 g of p-polyphonyl~no eulfoxide aro introducod at 80C in 200 ml o~ dilute hydrochlorio acid 13 g of ~ ~;
zinc aro then addod in the course of 4 houre The remaining polymer is filt~red of, wa~hed until neutral and dried :::
Yield 1 9 g Electron spectroscopy for chemlcal analyeio (~S Q) inveotigations of the ~ulfur 2p eignal (Fig 1) ~how a reduction of 33 % of tho ~tarting eulfoxido groups 3 ) Photochemlcal r-ductlon Polyphonylcno eulfoxide wae irradiat-d with photone o~ n~r~y 20 V (radiatlon of a comm-rcial UPS l~mp, typ- W 8 10/35 from 8poc~ ~mbH, Berlln) or 1200 -14,000 V (nonmonochromatiz-d Mg R~ radlatlon of a comm~rclal EgCA un~t, PhI 5500 from Physical El-ctronlce GmbH, Iemanlng) Tho ~ampl- wae ln an ultrahlgh vacuum ~nd at room tomp-raturo Aft-r an irradlatlon tlm- of 60 minut-o, tho ampl- wae analyz-d ln th- amo ~8CA unit u-lng no¢hromatizod ~ ;~
~l R~ radiation Tho r-eult of tho analy~ie ie ~hown ln Tablo l , ' ~:',.',' "'"~
Tabl- l ll~ts th- data for photon eourcoe of 20/40 oV and 1253 - 14,000 oV

.:, . . !

~13~
_ 7 _ Table 1 , _ , Source Irradintio~ Dogroe of Dogro~ of ¦
time reduction oxidation 20 eV / 40 sv 60 mln 80 % 20 ~
1253 - 14,000 60 mln 87 % _ 5 4 ) Thermal roduction ~ ;

Tho followlng oxamplos wero carrlsd out for poly-phenylono sulfoxlde aocordlng to l ) undor different conditlone -, . .
Flg 2 show~ tho ESCA S2p sp-ctrum whlch was rocordod wlth a commorclal ESCA apparatue uoing monochromatlzod Al K radiatlon, a reductlon at 10-9 mbar in an ultrahigh vacuum and a tomperature of 280C Tlmo 10 h The conv-rslon to PPS 1 guantitativo It was addltionally poeslble to check th- convorelon to PPS ln volum- by a m-ltlng polnt determination Flg 3 ~hows an BSCA 82p ~poctrum of a eampl- whlch wa~ hoat-d at 290C for 5 hour~ ln a glaee apparatue- ;
~n a tub- furnac- Th- proesuro ln tho apparatu~ wae ~ -about 10~ mbar Tho apparatus was evacuatod usln~ a turbomolocular pump and a rotary vans pump An almo~t compl~to convorolon to PPS ie dl~cornlblo ov-n hor- ln tho FSCA epoctrum An addltlonally r-aordod IR,0p-ctrum howe that no longer aro ny ~ ~
~ul~oxlde ~roup~ contaln-d ln the ~amplo ;; , ~;

Flg 4 ehowe an ESCA S2p ~poctrum of a amplo whlch~ ,~
wae heat-d for 4 houre t 290C ln lr Th~
troat~ont took plaa- ln a commerclal cloe-d furnac~
wlthout an addltlonal gae etroam The ESCA ~poctrum of tho S2p slgnal showe a guantltatlv- roductlon to PPS Thls rosult wae conflrmed by an IR analysis ~
'": :' ', ' : :.:

Claims (8)

1) A process for the preparation of polymer sulfides, which comprises treating compounds containing sulfoxide linking groups of the formula (I) -[(Ar1)n-X]n-[(Ar2)i-Y)]j-[(Ar3)k-Z)]l-[(Ar4]o-W)]p- (I) in which the symbols and indices have the following meaning:

Ar1, Ar2, Ar3 and Ar4 are identical or different arylene systems having 6 to 18 carbon atoms, W, X, Y and Z are identical or different -SO2-, -S-, -SO-, -CO, -O-, -CO2-, alkylene or alkylidene groups having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, where at least one linking group W, X, Y or Z must be an -SO- group, n, m, i, j, k, l, o and p are, identically or differently, 0 or an integer 1, 2, 3 or 4, where their total must be at least 2, a) thermally or b) in the presence of active hydrogen or c) photochemically and reducing to hive the corresponding sulfides.

2) The process as claimed in claim 1, wherein compounds containing recurring units of the formula (II) are employed (II) in which Ar5 and Ar6 are naphthylene, bi- or tri-phenylene or phenylene and in which the ratio of oxygen to sulfur is ? 1 and > O, the total of a and b always being 1.

3) The process as claimed in claim 2, wherein the recurring units employed are of the formula III

(III)

4) The process as claimed in one or more of claims 1 to 3, wherein the reaction is carried out with active hydrogen in Br?nsted acids by addition of base metals having an electrode potential which is below that of hydrogen.

5) The process as claimed in one or more of claims 1 to 3, wherein the reaction with active hydrogen is carried out under homogeneous conditions in an autoclave.

6) The process as claimed in one or more of claims 1 to 3, wherein the reaction reaction active hydrogen is carried out in an autoclave by suspension hydrogen-ations in saturated aliphatic alcohols using C1-C5 saturated aliphatic alcohols and/or in saturated aliphatic carboxylic acids.

7) The process as claimed in one or more of claims 1 to 3, wherein the photochemical reaction is carried out using radiation sources in the energy range between 0 5 and 1,000,000,000 eV.

8) The process as claimed in one or more of claims 1 to 3, wherein the thermal reaction is carried out in a vacuum oven in the pressure range from 1 bar to 10-9 mbar between 100 and 600°C.