Dimethyl-2,6-naphthalene dicarboxylate

Although the superior properties of PEN have been known for many years, the unavailability of the naphthalate monomer has delayed the development of commercial markets, until relatively recently (1995) when the Amoco Chemical Company offered high purity naphthalene-2,6-dimethyl dicarboxylate (NDC) in amounts of up to 60 million pounds per year. This diester is produced by a five-step synthetic route, starting from the readily available compounds, o-xylene and 1,4-butadiene [3], Prior to this, the NDC diester was obtained by extraction of 2,6-dimethylnaphthalene (DMN) from petroleum streams, where it was present in relatively low abundance. Oxidation of DMN to crude 2,6-naphthalene dixcarboxylic (NDA) is conducted by a similar process to that used for conversion of p-xylcnc to purified terephthalic acid (TA), crude NDA is esterified with methanol, and is then distilled to yield high purity NDC. Other companies (e.g. the Mitsubishi Gas Chemical Company) followed Amoco s introduction with lesser amounts of NDC. Teijin [4] has manufactured PEN for many years for its own captive uses in films. 

The manufacture of polyethylene naphthalate) (PEN) is carried out using dimethyl 2,6-naphthalene dicarboxylate (NDC) and EG and is similar to the manufacture of PET from DMT. The IV after the melt is typically in the range of 0.5... 

PEN is produced from 26DMN analogously to how PET is produced fromp-xylene. The 26DMN is oxidized to dimethyl 2,6 naphthalene dicarboxylate and then polymerized with ethylene glycol to produce PEN. The 26DMN can be synthesized by a number of methods mentioned by Lillwitz [44]. 

With one exception, naphthalen-l,4-imines with a double bond between C-2 and C-3 are not known to dissociate thermally by either possible retro-Diels-Alder pathway (the reverse of reactions described in Section III, A, 1 and 2), and the enthalpy requirements for the formation of a benzyne or an acylic acetylene are doubtless unfavorable. However, the mass spectra of compounds 93-99 reveal one important fragmentation of the molecular ions to be loss of dimethyl acetylene-dicarboxylate, and another fragmentation pathway involves the formation of nitrilium ions MeC=NR and PhC=NR from 93-95 and 96-99, respectively. ... 

On the basis of the formal similarity between 1,8-diamino-naphthalene and 3,4-diaminothienothiophene (1) the latter might be able to form a fused pyrimidine system on reaction with orthoformic ester or formamide. However, heating dimethyl 3,4-diaminothieno[2,3-6]-thiophene-2,5-dicarboxylate with acetic anhydride gave the corresponding MiV -diacetyl derivative, while 3,4-diacyloxy derivatives resulted from analogous reaction of dimethyl 3,4-dihydroxythieno-[2,3-6]thiophene-2,5-dicarboxylate with orthoformic ester and acetic anhydride."... 

Copolynaphthalene ester films were prepared by transesterification/esterifi-cation of dimethyl naphthalene dicarboxylate and dimethyl isophthalate with aliphatic diols by Hebrink et al. (1) and used in optical polarizing films with color shifts. 

Acid treatment of cyclobutanecarboxylic acids with an external /(-carbonyl group was reported to give good yields of decarboxylated compounds. For example, dimethyl 3-oxo-l,2,2a,3,8,8a-hexahydrocyclobuta[/j]naphthalene-2a,8a-dicarboxylate was treated with acetic acid, water and sulfuric acid at 100°C to give 8-oxo-l,2,2a,3,8,8a-hexahydrocyclobuta[6]naphthalene-2a-car-boxylic acid (5) after in situ hydrolysis in 91 % yield.8... 

Figure 38. (a) Absolute configuration of (55,125)-(+)-dimethyl-5,12-dihydro-5,12[l, 2 ]-benzonaphthacene-l,15-dicarboxylate (b), (c) and (d) orientations of pairs of electric transition dipole moments from the chromophores 1 and 3 from the methylbenzoate chromophores 2 from the naphthalene. The helicities are shown to the right. The 1,3 couplet is predicted to be zero since the dipoles are parallel. The 1,2 and 2,3 couplets have (+) chirality. The net chirality is predicted to be (+). (e) CD Cotton effects for the intense 233 nm transition of the benzotriptycene showing a (+) exciton chirality. 

PB PBI PBMA PBO PBT(H) PBTP PC PCHMA PCTFE PDAP PDMS PE PEHD PELD PEMD PEC PEEK PEG PEI PEK PEN PEO PES PET PF PI PIB PMA PMMA PMI PMP POB POM PP PPE PPP PPPE PPQ PPS PPSU PS PSU PTFE PTMT PU PUR Poly(n.butylene) Poly(benzimidazole) Poly(n.butyl methacrylate) Poly(benzoxazole) Poly(benzthiazole) Poly(butylene glycol terephthalate) Polycarbonate Poly(cyclohexyl methacrylate) Poly(chloro-trifluoro ethylene) Poly(diallyl phthalate) Poly(dimethyl siloxane) Polyethylene High density polyethylene Low density polyethylene Medium density polyethylene Chlorinated polyethylene Poly-ether-ether ketone poly(ethylene glycol) Poly-ether-imide Poly-ether ketone Poly(ethylene-2,6-naphthalene dicarboxylate) Poly(ethylene oxide) Poly-ether sulfone Poly(ethylene terephthalate) Phenol formaldehyde resin Polyimide Polyisobutylene Poly(methyl acrylate) Poly(methyl methacrylate) Poly(methacryl imide) Poly(methylpentene) Poly(hydroxy-benzoate) Polyoxymethylene = polyacetal = polyformaldehyde Polypropylene Poly (2,6-dimethyl-l,4-phenylene ether) = Poly(phenylene oxide) Polyp araphenylene Poly(2,6-diphenyl-l,4-phenylene ether) Poly(phenyl quinoxaline) Polyphenylene sulfide, polysulfide Polyphenylene sulfone Polystyrene Polysulfone Poly(tetrafluoroethylene) Poly(tetramethylene terephthalate) Polyurethane Polyurethane rubber... 

Polyethylene naphthalate (PEN) polyesters are made from 2,6-naphthalene dicarboxylic acid or 2,6-naphthalene dicarboxylic acid, dimethyl ester. They have higher temperature resistance than amorphous PET and are increasingly used in applications requiring heat sterilisation of the food/drink, although PEN at the moment is significantly more expensive. Table 10.5 lists commonly used substances in polyesters. 

Reductive bisalkylation. Treatment of (1) with 2 eq. of naphthalene-lithium (lithium naphthalenide) at —78° in THF affords dimethyl 1,4,6-cyclooctatriene-1,2-dicarboxylate (2) in 60% yield.1... 

Naphthalene does not react with sodium in ether, but Scott found that when sodium is introduced to a solution of naphthalene in dimethyl ether or in ethylene glycol dimethyl ether the metal dissolves to give a deep green solution. Carbonation of the green solution gave a mixture of naphthalene, A -dialin-3,4-dicarboxylic acids, and A"-dialin-l, 4-dicarboxylic acids, and the result led Scott to infer that the solution contains the complex (C,(,HaNa.)C oH8. However, a quantitative study of the reaction in tetrahydrofurane by Paul" indicated that the metal dissolves by... 

The product of thermal isomerization of this cyclopropane, dimethyl (l-naphthyl)malonate, was also formed (5-10%), together withtetramethyl2,3-benzo-ant -tricyclo[5.1.0.0 ]oct-2-ene-5,5,8,8-tetracarb-oxylate (5-15%) and dimethyl 377-benzocycloheptatriene-3,3-dicarboxylate (5-10%) which is likely to arise from an intermediate cyclopropane arising from carbene addition to the 2,3-bond of naphthalene. 

Irradiation of a solution of dimethyl acetylenedicarboxylate in a 14-fold molar excess of molten naphthalene at 90 °C with UV light for four days in a quartz apparatus gave an 11 % yield of 1 1 adducts, among which the major product (34%) was dimethyl 3,4-benzo-tricyclo[3.3.0.0 ]octa-3,6-diene-6,7-dicarboxylate (14). ... 

The reaction of the relatively unstable phosphine oxide (20) with dimethyl acetylenedicarboxylate gives dimethyl naphthalene-2,3-dicarboxylate. This... 

The most apparently desirable of the minor components is the 2,6-dimethyl naphthalene which can be used to make naphthalene-2,6-dicarboxylic acid, which in turn can be used to make special polyesters (3). Following oxidation of the alkylated naphthalenes (the alkyl groups do not necessarily have to be methyl, but the substitution pattern is important) the resulting dicarboxylic acids should be readily marketable. However, since the overall yields of naphthalene derivatives in the synthetic gasoline are low, this fraction is unlikely to be of commercial value in the near term. This is unfortunate, because these compounds are also unsuitable for gasoline as their boiling points lie outside the required specification. 

A dimethyl 1-naphthol-2.3-dicartx)xylate compound has been synthesised from phthalide. Thus 2-methoxyphenyllithium, prepared from 2-bromoanisole and n-butyllithium, was reacted with phthalide in tetrahydrofuran solution at -78°C during 30 minutes and after the reaction mixture had attained ambient temperature during a further 30 minutes, 4 moles of dimethyl acetylene (DMAD) in dichloromethane were introduced. Following completion of reaction overnight, and removal of excess reagent, the crude product was aromatised by refluxing for 4 hours with a benzene solution of toluenesulphonic acid to afford dimethyl 1 -hydroxy-4-(2-methoxyphenyl)naphthalene-2,3-dicarboxylate (ref.53). 

NDA can be purified by esterification with methanol and allow to fractionally crystallize the dimethyl-2,6-naphtbalene dicarboxylate (NDC) and monomethyl-2,6-naphthalene dicarboxylate. 

Poly( 1,3-propylene 2,6-naphthalate) (3GN) is synthesized from dimethyl-2,6-naphthalene dicarboxylate and 1,3-propanediol. The ingredients are reacted under atmospheric pressure under nitrogen in the presence of Ty-zorTM titanium tetraisopropoxide catalyst. The vessel is heated to 240°C over a period of about 330 min. At 188°C, methanol started to evolve. 

Naphthalates Physical properties and handling information for dimethyl 2,6-naphthalene dicarboxylate. Company Data Sheet N-2, BP Sales Administration and Customer Service, 150 West Warrenville Road, 605-CS 3, Naperville, Illinois 60563-8460, November 2004. 

N Clear Sodium Silicate. See Sodium silicate NCMC. See Carboxymethyl chitosan N-Creamer 46. See Food starch, modified NCS. See N-Chlorosuccinimide NC Size C-25. See Styrene/acrylates copolymer ND-201 Syrup. See Malt extract 2,6-NDA. See 2,6-Naphthalene dicarboxylic acid NDBC NDBC. See Nickel dibutyidithiocarbamate NDEA. See N-Nitrosodiethylamine NDGA. See Nordihydroguaiaretic acid NDI. See 1,5-Naphthalene diisocyanate NDMA. See N,N-Dimethyl-p-nitrosoaniline N-Nitrosodimethylamine... 

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