CA1075260A - Tetramethylbiphenylcarboxylic acids and derivatives thereof - Google Patents

Abstract

Abstract of the Disclosure This specification discloses 2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylic acid compounds suitable for producing polymers useful for forming shaped objects, such as film, fiber and molded parts.

Description

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Thl8 inventlon relates to 2,2',6,6'-tetra~ethylblphenyl-4,4'-dl-carbo~yllc acid compound~ sultable for producing polymers useful for - for~lng shaped obJects, such as fllm, fiber and ~olted parts.
; As 18 woll known, the mechanlcal and physlcal properties of a flber .~, - 5 or film depend~ on the chemlcal ~tructure of the poly~er from whlch it 1~ made. For example, the melting polnt ant glass transltlon temper--ture or a polymer composltlon control~ ~any of the physlcsl properties of shapet obJects. The meltlng polnt deter~lnee thermal resistsnce, ' ~afe lronlng temperature and heat-~ettln8 t _ ersture of fibers. Glass ~ 10 tr-nsltlon temperature (Tg) determines inltlal modulus, tenslle straln - ~ ~ recoverg, work of recovery, drape and hand, wash-ant-wear chsracterlstlcs, comfort factors and resillence of fibers. The ~ain lecular factors -: whlch influence theee propertles lnclude chaln stlffness, the lnterool-, ;s ; ecular forces, orlentation ant crystallinity.
:, , Accortlngly, there has been conslderable lnterest in developlng aromatlc symmetrlcal aclds a~ precursors for thermally ~table polymers, ~uch nfl polyesters or poly~mldes. It i~ well known thut the lntroduc-tlon of aromatlc unltu ln the polyoer chain backbone results ln hlgh bont energle~, a low tegree of reactlvlty, and rlgldlty of the polymer chaln structure. The use of allphatlc unlts in the polymer ch d n back-bone results ln flexlbility, lower temperature characteristics nd de-creased strength as compared wlth the aromatic types.
; ~ Substantially all commerclal polyester fibers are based on tereph-.. ., .
- thallc acit. Whlle these flbers have many crcellent propertles there ~ 25 :' . .

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., 1075'~;0 i8 a need for polyester flbers having a higher T8 than provided by terephthallc ~cld polyesters. Recently, 2,6-nsphthalene dlcnrboxylic acld hss been proposed as a sultable aromatlc acld for producing poly-esters sultable for tire cord. This scid provides polyesters having 8 higher Tg than those based on terephthalic acid. For ehample, poly(ethy-lene terephthalate) has a Tg of about 75C while poly(ethylene 2,6-¦naphthalene dlcsrboxylate) has a Tg of about 115-125C. However, ehe ¦dlfficultles of manufacturing the precursor, l.e., 2,6-dimethylnaph-¦thalene, has made the production of thls acid technically difficult and ¦ economlcally costly. The acid requires a four-step synthesis with ¦ attendant 10B8 in yield and consequent high cost.
¦ Varlous other organic polymers have been suggested for use as high temperature fibers, such as copolysmldes (K~vlar), polybenzimidazoles, polyoxadiazoles, polyim1des ant highly fused rlng systems (polyphenyl-enes). Polysrylatee ant polycarbonates have been suggested for use as englneerlng plastlcs. However, all of these are costly andlor diffi-cult to manufscture. Accordin~ly, there 18 a need for new aromatlc aclts sultable for preparing polymer~ for many uses.

The general ob~ect of this invention is to provide a new aromatic polycarboxylic acld compound and polymers thereof. A more speclflc ob-Ject of thi8 lnvention 1B to provide a new polycarboxylic acid, specifi-cally 2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylic acid and a method for its production. A further ob~ect 18 to provlde novel polymers, both polyamide~ and polyesters, made from these aclds and their sl~ple esters.
2s Other obJects appear hereinafter.

In one aspect this invention relates to tetramethylbiphenyl dl-carboxylic acid compounds tacids and esters of nohydroxy compounds).
' In a second aspect this invention relates to a method of producing i tetramethylbiphenyl dicarboxylic acld compounds.

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1075;~0 In a third aspect this invention relates to polyesters based on tetramethylbiphenyl dicarboxylic acid compounds.
In a fourth aspect this invention relates to polyamides based on tetramethylbiphenyl dicarboxylic acid compounds.
Thus the present invention provides 2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylic acid compounds selected from the group consisting of the dicarboxylic acids, diacyl halides thereof, and diesters thereof containing from 1 to 24 carbon atoms in each ester moiety.
In another aspect the present invention provides a high molecular weight polyester comprising a polyhydroxy component and polycarboxylic acid component wherein 2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylate moieties comprise at least 5 percent of the acyl equivalents in the poly-ester.
In a further embodiment the present invention provides a high molecular weight poly-2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxamide.
In a preferred aspect of this embodiment the carboxamide groups are joined by arylene groups, most preferably the arylene groups comprising ~ CH

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In another embodiment the present invention provides a process of producing the dicarboxylic acid compounds~set out above, which comprises oxidizing the para methyl groups of bimesityl and recovering 2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylic acid.
These compounds (acids, acyl halides, simple esters, e.g., methyl, etc.) are desirable intermediates for produci~g condensation polymers, such as polyamides and polyesters suitable for forming shaped articles such as film, fiber and molded parts. The esters of this acid and monohydroxy ~ _ 3 _ ~j 1075~

compounds containing 4 to 24 carbon atoms can be used as plasticizers for polyvinylchloride (PVC).
Although an abstract of an article by Y. Nomura and Y. Takeuchi (J. Chem. Soc. (B) 1970, 956-960) mentions the structure 2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylic acid and its methyl ester, there is no further reference to these compounds or to their properties or preparation given in the abstract or in the article. There is no indication that these compounds were made nor suggestion how to make these compounds.
Low yields of other substituted biphenyls are reported by the authors.
For example, 4.8 grams of 4,4'-diamino-2,2',6,6'-tetramethylbiphenyl was prepared in 52% yield from 3,5-dimethylnitrobenzene which in turn yielded only 0.10 grams of 4,4'-dicyano-2,2',6,6'-tetramethylbiphenyl in 2% yield, and an overall yield of only 1% to the dicyano compound.
I have now found that 2,2',6,6'-tetramethylbiphenyl-4,4'-dicar-boxylic acid can be prepared by the oxidation of the para methyl groups of bimesityl using molecular oxygen in the presence of a cobalt compound, as for example cobaltic acetate; and the process is especially convenient and advantageous if carried out in the presence of an organic acid, preferably acetic acid. The ortho-methyl groups (the 2 and 6 methyl substituents of the bimesityl) are relatively stable and the oxidation yields primarily 2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylic _ 3(a) ~

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~acld or its precur~or whlch csn be oxidlzed to the d~acid.
¦ In soDewh~t greater detsll bimeslty1 i8 reacted wlth sn oxygen-con-¦talnlng gss (oxygen, ulr, etc.) ln the presence of cobaltlc ions at a ¦temperature within the range of 20 to 150C, preferably 70 to 120C, ¦under pressure. While the reaction can be csrried out neat, it is ¦generally preferred to use an organic solvent to prevent sublimination ¦of the blmesityl. Suitable organic carboxylic acids include acetic ¦acid, propionic acid, benzoic acid, etc. Approximately .01 to 3 parts ¦by weight cobaltlc ion per part by weight bimesityl compound can be lo ¦ u~ed. In general the hi8her the concentration of cobaltic ion the faster the rate of oxidation. The acid can be isolated by conventional means or esterlfled with a lower alcohol (methanol, ethanol, isopro-panol) to facllltate separatlon and purlfication.
2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylates can be produced ¦ by reactlng the appropriate 2,~',6,6'-tetramethylbiphenyl-4,4'-dicar-I boxylic acld compound (free acid or acyl halide) with a suitable mono-! hydroxy compound at a temperature of 60 to 200C or the dimethyl estercan be produced first and the appropriate diester produced by trans-l e~teriflcation wlth a suitable monohydroxy compound at a temperature of 1 60 to 200C.
Sultable monohydroxy compound~ useful for producing these monohy-droxy e~ters lnclude alcohol~ containlng from 1 to 24 carbon atoms such as methyl alcohol, ethyl alcohol, isopropyl alcohol, allyl alcohol, l methallyl alcohol, n-butyl alcohol, n-hexyl alcohol, n-octyl alcohol, 2- ¦
2s I ethylhexyl alcohol, decyl alcohol, trldecyl alcohol, stearyl alcohol, oleyl alcohol, tetracosyl alcohol; aromatic hydroxy compounds containing from 6 to 24 carbon atoms, such as phenol, cresol, para-stearyl-phenol, naphthol, etc., benzyl alcohol, etc.
l These esters can be produced under conventional reaction conditions 30 ¦I by reacting from about 1 to 10 moles of monohydroxy compound per car-1i !

,1 , ~,, )75'~60 ,1 oxyl equivalent of said tetramethylbiphenyl dicarboxylic acid compound to form 8 solution of ester and monohydroxy compound. If deslred esterl-~icstion catalysts or transe~terlflcation catalysts can be used, such as l sulfurlc acid, phosphoric acid, para toluene sulfonic acid, benzene s ¦ sulfonic acld, stsnnous octoate, boron trifluoride etherate, tetralkyl titanates and zirconates of U.S. Patent 3,056,818, etc.
The esters of monohydro y compounds containing from 1 to 4 carbon stoms in each alkyl group can be used advantageously in ester inter-I change proces~e6 for producing high molecular weight polyesters while the diesters containing from 1 to 24 carbon atoms ln each ester moiety, preferably alkyl groups containing from about 4 to 13 carbon atoms, can be ueed as plasticizers for resinous polymers of vinyl chloride contain-lng at least 50 mole percent vinyl chloride unlts. The resinous poly-mers of vlnyl chloride include homopolymeric polyvinyl chloride, 95/5 ls vlnyl chloride/ vlnyl acetate copolymers, etc. The plasticlzers can be u~ed in a concentratlon of from 5 to 300 parts by weight per each 100 parts by weight re-lnous polymer of vinyl chloride as the sole plas-tlclzer or together wlth other plasticizers such as dloctyl phthalate, trioctyl phosphate, epoxidized glyceride oil8, etc.
1 The 2~2'~6~6'-tetramethylbiphenyl-4~4'-dlcarboxylic acld compounds can be u~ed sdvantageously to produce hlgh molecular welght film-forming or flber forming polyesters and polycarbon~mides The polyester6 of this invention comprlse a polyhydroxy component comprlsing one or more polyhydric ~lcohol~ (dlol~, trlols, etc.) and a polycarboxyllc acid com-2s ponent comprising a 2J2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylate component. The preferred polyesters of this lnvention are es~entially linear and compri~e unlt~ of alkylene glycols containing 2 to 12 carbon atoms and 2,2',6,6'-tetramethylbiphenyl-4,4'-dlcarboxylate moieties.
The polyesters based on 2,2',6,6'-tetramethylbiphenyl-4,4'-dlcarboxylate have an exceptionally hi8h Tg. For example, homopolymeric polyethylene ~5~

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2,2',6,6'-tetramethylbiphenyl-4,4'-dlcarboxylate has a Tg of about 1910C, homopolymerlc tetrsmethylene 2,2',6,6'-tetr~methylbiphenyl-4,4'-dlcarboxylate h~ a Tg of 131C, homopolymerlc polyethylene terephtha-l late has a Tg of about 75C and homopolymeric polyethylene naphthalene ¦ 2,6-dicarboxylate has a Tg of 115-125C. Accordlngly, the polyesters of this lnvention comprise 2~2~6~6~-tetramethylbiphenyl-4~4'-dicarboxylate moieties and polyhydric alcohol moietles.
Broadly speaking, the polyesters of this invention can be prepared by reacting the polyhydrlc alcohol or alcohols with the dicarboxylic acld component or components (acid or lower alkyl ester of dicarboxylic acid). An ester-formlng derivative of the dicarboxylic acid may be used, i.e., an acid halide, a salt, lts anhydrlde and/or an ester there-of, particularly an e~ter with a lower aliphatic slcohol or with phenol.
Correspondlngly, ester-forming derlvatlves of the polyhydrlc alcohols may be employed, $.e., a derivative of the alcohol containing functional groups equlvalent to the hydroxyl groups ln their ability to react with carboxyl groups. Thus, an alcohol may be employed in the fonm of an epoxide, and/or ester of the alcohol wlth acetic acld or other lower i aliphatic acid may be used.
In a convenient method for preparing the dihydric alcohol dicar-I boxylate polyester, the dimethyl e~ter of the dicarboxylic acid or acids I is reacted with an exces~ of the polyhydrlc alcohol, 1.1 to 2.5 moles of polyol per mole of ester, preferably employing about 1.5 to 2.1 m~le~ of j polyol per mole of ester. The reactlon is usually carrled out at atmos-pheric pressure but higher or lower pressure can be used if desired. A
range is usually from 0.1 to ten atmospheres. Temperature is usually from 90DC to 32$C. Following the ester interchange reaction, in which l a lower alcohol i8 removed as a by-product, heating is continued at an ¦l increa~ed temperature to bring about polycondensation. Small amounts of j cat~lysts can ~e added to facilitate the reactlon. Manganous acetate, ~ 6-ii ~ 1~75260 ¦calclum acetate, and sod~um mæthoxlde are typical ester lnterchange ¦catalysts while antimony trioxide, dibutyltin maleate, and zinc acetate lare suitable polycondensation catalysts. Litharge, sodium hydrogen l hexabutoxytltanate and the tetra-alkyl titanAtes, such as tetra-iso-¦ propyl titanate, are examples of catalysts which may be used for boththe ester interchange and the polycondensation steps. Normally, the polycondensatlon reaction i8 contlnued until a degree of polymerizatlon i8 schleved correspondlng to an intrinsic vlscosity of approximately at least 0.3 dlJg ln a 60l40 phenol-tetrachloroethane solvent at 30C.
0 ¦ To achieve a higher degree of polymerization, the product of the polycondensation reaction 18 allowet to cool to room temperature, about 20 Lo 25C, forming a solid material. The solid is ground to flake, following which the flake is heated below its melting point in a stream of inert gas to achieve solid phase condensatlon.
S The tetrsmethylbiphenyldicarboxyllc acid can provide from about 5 to lO0 percent of the acyl equivalents in the polyester, preferably 20 to 100. Various other acid co-monomer~ include aromatic polycsrboxylic aclds, such as terephthalic acid, phthalic acld, phthalic anhydride, isophthallc acld, 2,6-naphthalene dicarboxylic acid, trimellitic anhy-dride, trimellitic acid, etc.; saturated aliphatic polycarboxylic acids, ¦such as adipic acid, sebacic acld, 1, 2, 3, 4, butane-tetracarboxylic ¦acid, etc.; unsaturated aliphatic dicarboxylic acids, such as maleic acld, malelc anhydride, fumaric acid, etc. In general, the organic acids or acyl compounds containing three or more acyl groups comprise up to about 2% of the acyl equivalents in the polyester and the difunc-tional organic aclds comprise at lea~t g8%.
The polyhydric alcohols useful for producing the polyesters of thisinvention include al~ylene glycols containing from about 2-12 carbon l,atoms, such as ethylene glycol, 1,2-propylene glycol, 1,3-propylene 30 1I glycol, butylene glycol, hexame~hylene glycol, dodecamethylene glycol, i~ ~7~

i i I1 107S~0 letc.; aromfltic l-olyhydric alcohols, such as hydroquinone, resorclnol, ¦Bisphenol A, etc.; cycloaliphatic ~lycols such as 1,4-dimethylol cyclo-¦hexsne, dlmethylol cyclobutane, etc.; polyoxyalkyleue glycols, such as ¦polyoxyethylene glycol~, polyoxypropylene 81YCO1B, block copolymers of ¦polyethylene and polypropylene glycol, polytetramethylene glycols, etc.;
neopentyl glycol, polyhydric alcohols having three or more hydroxy groups, such as l,l,l-trimethylol ethane, l,l,l-trimethylol propane, ¦penta erythritol, sorbitol, reaction products of the aforesaid poly-¦hydrlc alcohols having a functlonality of three or more wlth alkylene ~0 ¦oxldes (ethylene oxide and/or propylene oxlde) such as those sold for ¦use in the productlon of flexible polyurethane foams, etc, In general, ¦the polyhydrlc alcohols h8ving a functionallty of three or more should ¦provlde no more than about 2 mole X of the polyester. For optimum fiber ¦and film propertie~, it i~ generally preferred that elther ethylene ¦glycol and/or butylene glycol comprise approxlmately 100 mole ~ of the polyol portion of the copolyester of this invention.
In tho~e casee where an alpha, beta-ethylenically unsaturated acid compound (maleic anhydrlde, fumaric acid, etc.) is used, the resulting I polyester can be dl8solved in a monovlnyl aromatlc (styrene, vlnyl-¦ toluene, etc.) and used ln moldlng compositions ln the same manner asother unsaturated polye~ters.
The e~sentlslly linear polycarbonamldes of this lnvention can be vlewed as poly-2,2',6,6'-tetramethyl-4,4'-blphenyl dicarboxamlde~ havlng l arylene and/or alkylene groups ~olning the amldo groups of the polymer.
5 ¦ One or more of the alkylene or arylene groups can be ~oined by one or H O
more heteroatoms (-O-, -N-, -S-, -S-, etc.) as is common ln this art.
Sultable alkylene groups contalning 2 to 24 carbon atoms include ethylene, trlmethylene, hexamethylene, octamethylene, dodecamethylene, ~ -8-i ! .
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! CH2 CH2 N CH2(~l2-~ C~2-C~2-N-CH2-CH2-N-CH2-CH2-~ tetracosene, etc.
¦Sultable arylene group~ contslnlng 6 to 24 carbon atoms include p-pheny-¦lene, o-phenylene, N,N-dlphenyleneamine, oxydiphenylene, etc.
¦ The high molecular weight polyamides can be prepared by well-known ¦methods. These methods include reacting tetr~methylblphenyl dicar-¦boxylic acid or its derivatives such as acid chlorides wlth alkylene and arylene diamines, diisocyanate6, diisothiocyanates and their deriva-tlves. For example, polyamides can be prepared from the free acid ~ ¦ (2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylic acid) and d~funct~onal nltrogen containing compounds such as diphenylmethane-4,4'-diisocyanate, dlphenylether-4,4'-diisocyanate, methylene bisaniline, p-phenylene diamine, etc.
In somewhat greater detall, the dicarboxyllc acid can be reacted with an excess of the aromatic diamine, diisocyanate or diisothiocyanate.
¦ (1.1 to 2.5 moles of reactant per mole of acld, preferably about 1.5 to 2.1 moles of reactant per mole of acid). The reaction can be csrried out at stmospheric pressure but higher or lower pressure can be used if de-sired. The temperature is ususlly from about 90 to 325C. Small amounts of catalyst can be added to fscllitate the reaction. Normally, the reaction 18 continued until the de3ired degree of polymerization is !l achieved.
¦ EXAMPLE I
~ Fifteen grams cobaltous acetate was stirred into 200 ml acetic acid ¦
¦ ln a 500 ml three-necked round-bottom flask equ~pped witb a thermometer, condenserf addition fumlel, electric heating mantle and magnetic stir-rer. Fifteen ml of 40% peracetic acid dissolved in acetic acid was l added slowly to the flask from the dropping funnel. The color of the ! reactants changed from red (Co++) to green (Co~+) Five to ten minutes l~ after the exothermic heat of reaction subsided, external heat was _ g_ -1~)75'~60 --upplied to the mantle to malntain the reaction temperature at 45C.
After the droppin~ funnel was removed, ten grams bimesityl was added and a gas dispersion tube ~as inserted for the dropping funnel and oxygen l was lntroduced at 0 3 SCFH. The reaction temperature was rai~ed to 95C
¦snd held within a range of 90-115C for five hours as indicated in Table I. Oxygen sparging and external heating were stopped and the reactants were allowed to cool to ambient temperature. The mixture was then filtered to obtain the precipitated solids, 2.7 grams and the filtrate ¦w88 ssvet. The insolubles were washed three times with 5 ml. of acetic ¦acld and then wlth concentrated hydrochloric acid to regenerate the free carboxyllc acids. The regenerated acids were approximately 80% diacid and 20% monoacld, The initlal filtrate produced ln the preceding paragraph was poured ¦lnto one llter of water, the preclpltate recovered, washed wlth re 1s ¦ water, and then dlssolved in 200 ml of ether. Extraction of the ether ¦ wlth 5% sodlum bicarbonate (NaHC03~ followed by acidification and flltra-tlon of the water extract ylelded a fraction thst was 85-90% biphenyl dlacld. A simllQr extraction with 5% potassium hydroxide ~KOH) gave a l fractlon that was 90-95% biphenyl mono-acld. The resldue in all cases ¦ after ether evaporation was malnly unreacted bimesityl. The amounts of the various aclds ln these fractlons were tabulated to glve the results shown ln Table I. Table I lists pertlnent data on four runs of selec-l tlve bimesltyl oxidation obtained by these method~.

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I1 10'75'~60 ¦ TABLE I

¦ Selective Oxldatlon of Blmesltyl And Products Obtsined RunRea~ents Temp Z ~eight of 10 Grams Bimesityl CStarting Materials Co(OAc)2-4H20 40~
_ 3COOOH DA MATA Others 110 1~.1 90-104 29 451 4 210 10.0 100-105 25 481 3 310 10.0 112-114 12 46~ 0.5 3 410 15.0 99-102 39 351 3 0 ¦ Note~:

DA -- Dlacid (2,2',6,6'-tetrsmethylblphenyl-4,4'-dicsrboxylic l acid) I NA -- Monoacid (2,2',4,6,6'-Pentamethylblphenyl-4'-carboxylic acid) TA -- May be tri-acid~
Others -- Probably aldehydes aDd/or alcohol~.

15 Analysi~ of these extracted fractions by nuclear magnetic resonsnce (NMR) was used to identify the maJor components present. Esterificatlon gas chromatography (EGC) then indicated the quantitative percent of the ma~or component together with the number and concentration of intermedi-ates and by-products. The ma~s spectra of the esters from EGC al80 con-firmed the identification of the maJor component and gave good evldence !of the structure of the intermediates and by-products.
The crude dlacld fractions (511 gms.) were mixed with 2.75 llters of methanol and 700 grams of dry hydrochlorlc acid in a 5 liter three-l necked flaHk equipped with a thermometer, condenser, mechanicsl stlrrer Zs ¦ snd separatory funnel and was heated at reflux (70-73C) for 4~ hours.

The reaction mixture was cooled to room temperature and the precipitated solids were removed by filtration with a Buchner funDel. The preclpltate ¦
was washed twice with methanol and drled. The methanol-solu U e esters ~' were recoverable by evaporating the methanol washings. The methanol-il washed esters, 349 grams, were dissolved in 2.8 liters of ethyl ether.

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~ 1075Z60 The solutlon was extracted five tlmes in the separatory funnel, once with 60 ml of a 5% solution of 80tiUm carbonate In water, once wlth 70 ml. of a 5% ~olution of sodlum hydroxlde in wster and three time~ each l wlth 100 ml of water. The solution was dried o~ernight over anhydrous ¦ calcium sulfate. The cslclum ~ulfate was flltered out and the ethyl ether stripped off using stmospheric dl~tillation. The residue was then vacuum flashed to a pot temperature of 270C at 9-11 mm of Hg. The flashed esters were then fractionally distilled in a ten-tray stlll to l separate the diacid esters and the monoacid e~ters. The dlacid esters were then recrystallized fro~ benzene and vacuum dried. The dimethyl 2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylate melted at 128-129C.
The benzene-free diacid was recovered by heating the ester in KOH
solution, acidifying with hydrochloric acid to excess hydrogen ion. The precipitated diacid was recovered by filtration. A water wash followed s by drying under vacuum completed the purification of the 2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylic acld.
EXAMPLE II
__ .
Thl~ example illustrates the production of hlgh molecular weight polyamldes and converslon into polyamide films suitable for high-tem-perature electrical insulation, typically having high dielectric con-8 tants.
One and one-half gram~ 2,2',6,6'-tetramethylbiphenyl-4,4'-dicar-l boxylic acid was dissolved in 5.8 grams of N-methyl-2-pyrrolidone in a Zs ~ small round-bottomed three-necked flask equipped with a thermometer, electric heating mantle and magnetic stirrer. The solution was heated to 150-170C with stirrlng. Over a period of 45 minutes, 1.25 grams of diphenylmethane-4,4'-diisocyanate was added whlle maintainin~ the tem-perature at 150-170C with stirring. Carbon dloxide was evolved. The temperature of 170C was maintained for an additional hour after which an additional 0.25 grams of diphenyl methane 4,4' diisocyanate were ~ -12-Ij !
j 1075'~60 added. Heatlng and stirring were continued for another 30 mlnutes at ¦170C. The ~olution WAR then dlluted with 3.0 8rams of N-methyl-pyrro-¦lldone to reduce the viscosity to Z5-Z6 (Gardner-Holdt) at 20X sol1ds.

I A second dilution with 3 0 grams of N-methylpyrrolidone was then made to ¦reduce sollds to 15%. A clear solution with vlscosity of 40 Stokes ¦resulted.
¦ The inherent vlscosity of the polyamide W88 determlned using a ¦Cannon-Fensky vi~cosimeter. The inherent viscosity was measured at 25C
at a concentration of 0.5~ by weight of the polymer in dimethyl acetamide.
¦ A fllm was then ca3t from a 15% weight solution upon a glass plate and cured with heat. The Massachusetts Institute of Technology ~MIT) film folding endurance test was used to measure film toughness.
EXAMPLE III
Example II was repeated u~ing 1.5 grams 2,2',6,6'-tetramethylbi-¦ phenyl-4 4~-dicarboxyiic acld and 1.75 grams diphenylether 4,4'-diisocya-nate ln place of the diphenylmethane diisocyanate (the same le ratio of reactants). Solvent was added to sd~ust the re~ultant polymer 801u-tion to 15% welght solids with a viscosity greater than Z6 ~Gardner-I Holdt) and equal to 148 Stokes. Inherent viscosity wa~ determined at ¦ 0.5% weight and cast film toughness determined.
EXAMPLE IV
Thls example illustrates the production of a polyamide from 2,2',-6,6'-tetramethylbiphenyl-4,4'-diacyl chlorlde and a diamine. The diacld chloride derivatlve wRs prepared by refluxing overnlght 2.0 gms of the 2S dlacld in 20 ml of thlonyl chlorlde with one drop R N,N-dlmethylfor-mamlde as catalyst. Excess thionyl chloride was evaporated. The re-sulting crystalline residue was dried in a moderate vacuum at 50C for two days. The melting point was 197-200C.
~ The polyamide was prepared by reacting 2.2 gms of the d~acid chlor- i l~ ide derivative with 1.30 gms of methylene bisaniline in 15 gm of ~ -13-N,N-dimethyl acetamide (D~C) as the solvent, at ambient temperature and Ipressure. The solvent mix was heated to 45-50C for 45 minutes and then ¦cooled to amblent temperature over 8 period of two hourJ. A clear ¦vlscous ~olutlon, viscosity 80 Stokes and 16% weight solids (calculated), S ¦resulted. DMAC was added to thin the polymer solution. Water was then ¦added to preclpitate the polymer which was separated by filtration. The ¦crumbly granule8 of preclpitated polymer were water-washed and dried overnight in a vacuum oven. The lnherent viscosity at 0.5% weight l concentratlon was determined. Cast film toughne~s wa~ measured.
¦ Product characterizatlons as to the films by the processe8 of Examples II to IV are 8ummarlzed in Table II.
TABLE II
Polyamldes From 2,2',6,6' Tetramethyl -4,4'-Dicarboxylic Acid Inherent Solution Film Folding 15 Example Viscosity(l)Vlscosity(2)Endurance (3) II 0 90 40 6500-10,000 (1.2 Mils) III 1.08 150 300 (1.3 Mils) IV 0.86 - 15-50,000 (0.9 Mils) (1) 0.5% in DMAC (N,N-dimethyl acetamide) (2) 15% solids in NMP (N-methyl-2-pyrrolldone)

(3) MIT Folding Endurance (Double Polds) EXAMPLE V
¦ Thl~ example illustrstes the production of a high molecular welght ~ homopolymeric polyethylene 2,2',6,6'-tetramethylbiphenyl-4,4'-dlcar-1 boxylate by ester lnterchange of the dimethyl ester with ethylene glycol ; I in melt foll~wed by solid state polymerization, Five grams of dimethyl 2,2',6,6'-tetramethylbiphenyl-4,4'-dicar-boxylate, 2.1 grams of ethylene glycol and 0.1 grams of dibutyltin ~ maleate were heated at 180-185C ln a test tube equipped with a nitrogen l¦bubbler and a side-arm. During the heatlng, nitrogen was slowly bubbled Il -14-)i ~ 1075;~60 ¦through the mlxture. After the mlxture wa~ heated for two hours, the ¦Illtrogen flow wac dlflcontlnued. A partlAl vacuum wa~ pulled on thc mlx-¦ture over Q perlod of 10 to 15 mlnutes, using a vacuum pump attached to Ithe slde-Qrm, and when the temperature rose to 260C a full vacuum (0.2 ¦mm Hg) was Qpplied and held for two hours. Inherent visco6ity of the ¦product was 0.21 deciliters per gram (dl/g), measured at a concentratlon ¦of 0.4 grams per deciliter in a 60:40 by weight mixture of phenol and ¦6ymmetrical tetrschloroethane.
¦ The above product was ground to ~10 mesh and heated in a test tube tO ¦ at 200-210C and O.05 mm Hg vscuum for 32 hours. After 16 hours, the ¦ whlte homopolymerlc ethylene 2,2',6,6'-tetramethylbiphenyl-4,4'dicar-boxylate had an inherent viscosity of 0.59 dl/g. After the second 16 hours the inherent vi~cosity was 0.84 dl/g.
EXAMPLE VI
~5 ¦ Thl~ example illu~trates melt polymerlzation to a relatively high I.V. One hundred twenty grams dimethyl 2,2',6,6'-tetramethylbiphenyl-

4,4'-dicarboxylate, 45.6 grams of ethylene glycol, 0.1 gram~ of dibutyltin maleate, 0.05 grams of calcium acetate and 0.5 ml of antimony trisbutox-lte were he~tet to 200C for two hours in a round bottom flask equipped wlth a mechanlcal stlrrer and two slde-arms. Nitrogen was bubbled slow-ly through the mixture during the period of heating with stirring.
After two hours a partial vacuum was pulled on the mixture for 10 to 15 minute~, using Q vacuum pump attached to the side-arm. When the tempera-¦ture rose to 260C, a full vacuum (0.1-2.2 mm ~g) was applied with 1 contlnued stlrrlng and kept for 8.0 hours. Inherent ~iscosity of the llght brown homopolymer was 0.87 dlJg measured as described earlier.
Strong fibers could be pulled from the melt.

! Polymerlzation data with several diols are in Table ~II.

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1 1075Z~;0 ¦ EXAMPLE VII
l Thl~ ex~mplc llluRtrates compre~ion moldlng of a polye~ter fllm of ¦thlH lnventlon. Homopolymerlc polyethylene 2,2',6,6'-tetr~methylbl-¦phenyl-4,4'-dlcarboxylate havlng an I.V. of 0.87 dl/g wss drled at 120C
s ¦and 635 mm ~30 lnches) Hg overnight and placed between aluminum sheets ¦and spacers to obtaln the desired thickness. The polyester was placed ¦ln a press at 240C and held under pressure for five minutes. The ¦sample was then removed from the press and sllowed to cool without ¦pressure. A fibergla~s blanket was used to cover the sample in order to ~o ¦~low the cooling rate. U~ing this procedure, a 0.87 dl/g polyester pow-¦der was molded to give a film with a 0.77 dl/g inherent viscosity. The ¦ lnherent vlscosity 1088 was approximately the same~as would be observed for poly(ethylene terephthalate). For compresslon molding of thicker ¦parts up to 125 mlls, a ten minute heatlng tlme was employed wlth a ls ¦plcture frame mold instead of aluminum sheets.
Phy~ical properties of the film and shaped (molded) parts made accordlng to the above procedure are given ln the following ta~le.
Table IV
l ProPertles of PEM2 Film and Molded Parts 20 ¦ Den~lty, g/cm3 1.12 Glass Tran~ltlon Temperature, C DTA ~191 Rheovlbron227 Heat Deflectlon Temperature C, 264 psl 172 Ultlmate Tensile Strength, psl 7658 Elongation at Break, % 4.1 Flexural Modulus, pi8 282,000 Young's Modulus dyne/cm2 1 X ~olO
l Tensile Impsct Strength, psi 41 25 ¦ Limiting Oxygen Index, % 2 27-27.5 EXAKPLE VIII
Thi~ example illustrates the production of a polyester containing ¦2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylate moieties, ethylene gly-¦col moietie~ and polytetramethylene ether glycol moieties. Ten grams Idimethyl 2,2',6,6'-tetramethylbiphenyl-4,4'-dlcarboxylate (0.0307 moles), ~ 1075260 4.2 8rAms ethylene glycol (0.0677 moles), 1.5 grams polytetramethylene eth~r glycol of molecular weight 560 ~0.0023 mole~) .l Rram dibutyltln maleate and .l gram of calclum acetste were heated at 160C for 240 mlnutes in 8 te~t tube equlpped wlth a nltrogen bubbler and a sidearm.
Durlng the heatlng, nltrogen was passed slowly through the mixture. A
partlal vacuum wae pulled on the mixture over a period of 10 to 15 min-utes, us1ng a VHcuum pump attached to the side-arm. After the tempera-ture reached 275C, full vacuum (0.9 mm Hg) was applied. The isolatet polyester had a Tg of 120C.
loEXAMPLE IX
Thls example lllustrates the productlon of polyester containing ,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylate ieties, terephthalate moleties and ethylene glycol moietles. Three and one-tenth grams di-methyl terephthalate (0.016 mole), 1.3 grams (0.004 le) dimethyl ,2',6,6'-tetramethylbiphenyl-6,6'-dicarboxylate ~M2DMe), 2.8 gramC
(0.044 mole) ethylene glycol, 0.05 grams zinc scetate and 0.05 grams alcium acetate were heated at 160C for 120 minutes in a ~est tube quipped with a nitrogen bubbler and a side-srm. During the heating, ~trogen was paoset ~lowly through the mixture. After two hours the 20emperature was raised to 210C and 0.05 ml antimony tri~butoxide was added. A partial vacuum was pulled on the mixture over a period of lO

! to 15 minutes, uHing a vacuum pump attached to the slde-srm. After the temperature was raised to 275C, full vacuum (0.9 mm Hg) was applied and the reactlon continued for 133 minutes. The copolyester containing a 2s 4:1 mole ratio of terephthalate to tetrsmethylbiphenyl carboxylate moietie~ had an intrinsic viscosity of 0.29 deciliters per gram (dlJg), s determined in a 60J40 phenyl-tetrachloroethane mixed solvent at 30C.

, ,!
1 i Il i 1075;~
¦ Copolyester~ of ethylene terephthalate (ET) and e~hylene 2,2',6,6'-¦teeramethylbiphenyl-6,6'-dlcarboxylate ~M2D) ln molc ratio~ 3:2, 2:3, ¦and 1:4 were prepared ln the ~ome apparatus by the same procedure. The ¦results sre set forth below in Table IV.

5 ¦ Table IV

l Propertles of the CoPolYesters ¦ Molar I.V. Tg IComPositlon ~atlo dl/g C Me}tlnR Point C

¦ET/M2D 1/0 0.60 74 275 10 ¦ET/~2D 4/1 0 29 95 140 ¦ET/M2D 3/2 0.31 119 140 ¦ET/M2D 2/3 0.55 145 185 ¦~T/M2D 1/4 0.40 169 210 IET/M2D 0/1 0.64 191 240 l5The above data indicates that as the concentration of terephthalate ¦ moleties to tetramethylbiphenyl dlcarboxylate moieties decreases, the meltlng point of the polymer lncrea~e~. As the concentrstion of the tetramethylblphenyl dlcarboxylate leties lncreases, the Tg of the l polymer lncreases llnearly. A 19:1 le ratlo terephthalate to tetra-¦ methylbiphenyl dlcarboxylate polyester havlng an I.V. of 0.63 dl/g has a Tg of 780C and falls on the some llne When the ethylene glycol ln the 4:1 mole ratlo torephthlate to ¦ tetramethylblphenyl dicarboxylate polyester was replaced wlth tetrs-¦ methylene glycol snd the polyester was pepared ln the same manner, a ¦ polye3ter wa~ produced havlng an I.V. of ~.53 dl~g and a Tg of 52-54DC.
In thls case also the Tg of the copolyester falls on linesr llne con-necting the Tg polnts of homopo b esters of polytetramethylene tereph-¦thalate and polytetrsmethylene-2,2',6,6'-tetramethylb~phenyI-4,4'-I dlcarboxylate 1~ l

Claims (24)

The embodiments of the invention in which an exclusive property property or privilege is claimed are defined as follows:

1. 2,2',6,6'-tetramethylbiphenyl-4-4'-dicarboxylic acid compounds selected from the group consisting of the dicarboxylic acids, diacyl halides thereof, and diesters thereof containing from 1 to 24 carbon atoms in each ester moiety.

2. The compound of Claim 1, wherein said compound comprises 2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylic acid.

3. The compound of Claim 1, wherein said compound comprises 2,2',6,6'-tetramethylbiphenyl-4,4'-diacyl halide.

4. The compound of Claim 3, wherein said diacyl halide comprises a diacyl chloride.

5. The compound of Claim 1, wherein said compound comprises a diester containing from 1 to 24 carbon atoms in each ester moiety.

6. The compound of Claim 5, wherein said diester is a dialkyl ester.

7. The compound of Claim 6 wherein said dialkyl ester is the di-methyl ester.

8. A high molecular weight polyester comprising a polyhydroxy com-ponent and polycarboxylic acid component wherein 2,2',6,6'-tetramethyl-biphenyl-4,4'-dicarboxylate moieties comprise at least 5 percent of the acyl equivalents in the polyester.

9. The polyester of Claim 8 wherein said polyester is essentially linear and said polyhydroxy component comprises alkylene glycol moieties containing 2 to 12 carbon atoms.

10. The polyester of Claim 8, wherein said 2,2',6,6'-tetramethyl-biphenyl-4,4'-dicarboxylate moieties comprises 20 to 100 equivalent per-cent of the acyl moieties in the polyester.

11. The polyester of Claim 10, wherein said polyhydroxy component comprises ethylene glycol moieties.

12. The polyester of Claim 11, wherein said polyester is a homo-polyester.

13. The polyester of Claim 10, wherein said polyhydroxy component comprises butylene glycol moieties.

14. The polyester of Claim 13, wherein said polyester is a homo-polyester.

15. The polyester of Claim 8, wherein said 2,2',6,6'-tetramethyl-biphenyl-4,4'-dicarboxylate moieties comprises 100 equivalent percent of the acyl moieties in the polyester.

16. A high molecular weight poly-2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxamide.

17. The polymer of Claim 16, wherein the carboxamide groups are joined by alkylene groups.

18. The polymer of Claim 16, wherein the carboxamide groups are joined by arylene groups.

19. The polymer of Claim 18, wherein the arylene groups comprise

20. The polymer of Claim 18, wherein the arylene groups comprise

21. The process of producing the dicarboxylic acid compound of Claim 1, which comprises oxidizing the para methyl groups of bimesityl and recovering 2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylic acid.

22. The process of Claim 21, wherein said process is carried out using a cobaltic catalyst.

23. The process of Claim 22, wherein said process is carried out at 20 to 150°C.

24. The process of Claim 23, wherein said process is carried out in an acetic acid medium.