4.4- biphenyldicarboxylates

The present method for preparing aromatic dicarboxylic acids has been used to convert phthalic or isophthalic acid to tereph-thalic acid (90-95%) 2,2 -biphenyldicarboxylic acid to 4,4 -biphenyldicarboxylic acid 3,4-pyrroledicarboxylic acid to 2,5-pyr-roledicarboxylic acid and 2,3-pyridinedicarboxylic acid to 2,5-pyridinedicarboxylic acid. A closely related method for preparing aromatic dicarboxylic acids is the thermal disproportionation of the potassium salt of an aromatic monocarboxylic acid to an equimolar mixture of the corresponding aromatic hydrocarbon and the dipotassium salt of an aromatic dicarboxylic acid. The disproportionation method has been used to convert benzoic acid to terephthalic acid (90-95%) pyridine-carboxylic acids to 2,5-pyridinedicarboxylic acid (30-50%) 2-furoic acid to 2,5-furandicarboxylic acid 2-thiophenecar-boxylic acid to 2,5-thiophenedicarboxylic acid and 2-quinoline-carboxylic acid to 2,4-quinolinedicarboxylic acid. One or the other of these two methods is often the best way to make otherwise inaccessible aromatic dicarboxylic acids. The two methods were recently reviewed. ... 

Photophysical Processes in Dimethyl 4,4 -Biphenyldicarboxy-late (4,4I-BPDC). The ultraviolet absorption spectrum of dimethyl 4,4 -biphenyldicarboxyl ate was examined in both HFIP and 95% ethanol. In each case two distinct absorption maxima were recorded, an intense absorption near 200 nm and a slightly less intense absorption near 280 nm. The corrected fluorescence excitation and emission spectra of 4,4 -BPDC in HFIP at 298°K shows a single broad excitation band centered at 280 nm with a corresponding broad structureless emission band centered at 340 nm. At 77°K, the uncorrected phosphorescence spectra shows a single broad structureless excitation band centered at 298 nm, and a structured emission band having maxima at 472 and 505 nm with a lifetime, t, equal to 1.2 seconds. 

Photophysical Processes in Pol,y(ethy1eneterephthalate-co-4,4 -biphenyldicarboxyl ate) (PET-co-4,4 -BPDC). The absorption and luminescence properties of PET are summarized above. At room temperature the absorption spectrum of PET-co-4,4 -BPDC copolymers, with concentrations of 4,4 -BPDC ranging from 0.5 -5.0 mole percent, showed UV absorption spectra similar to that of PET in HFIP. The corrected fluorescence spectra of the copolymers in HFIP exhibited excitation maxima at 255 and 290 nm. The emission spectrum displayed emission from the terephthalate portion of the polymer, when excited by 255 nm radiation, and emission from the 4,4 -biphenyldicarboxylate portion of the polymer when excited with 290 nm radiation. 

Examination of the corrected room temperature fluorescence properties of PET yarns revealed an excitation maximum at 342 nm with a corresponding emission maximum at 388 nm. At 77°K, in the uncorrected mode, the fluorescence spectra of PET yarns exhibited a structured excitation having maxima at 342 and 360 nm and a shoulder at 320 nm. At 77°K, PET yarns displayed a structured emission with maxima at 368 and 388 nm. As in solution, the copolymer yarns showed both fluorescence from the terephthalate portion of the polymer and the 4,4 -biphenyldicarboxyl ate portion of the polymer. Excitation at 342 nm produced an emission band centered at 388 nm. This excitation and emission correspond to the PET homopolymer emission. Excitation with about 325 nm light produced an emission with a maximum near 348 nm from the 4,4 -biphenyldicarboxyl ate portions of the polymer. 

In the yarns, the fluorescence of the 4,4 -biphenyldicarboxy-late unit is distinct and predominate both at 298 and 77°K. Examination of the phosphorescence spectra of the PET and PET-co-4,41-BPDC yarns revealed three emission maxima. In the PET homopolymer excitation with 310 nm radiation produced an emission at 452 nm from the terephthalate chromophore. In the copolymers excitation with either 305 or 310 nm radiation produced emission spectra with distinct maxima at 480 and 515 nm (t 1.2 sec), and a shoulder near 452 nm (t = 1.2 sec). The maxima in the phosphorescence spectra were assigned as emission from the 4,4 -biphenyldicarboxylate units of the copolymer. The observed emissions are bathochromatically shifted from the emission of 4,4 -BPDC in a glassed solvent. This is supported by the observed emissions from solid 4,4 -BPDC at 520 and 560 nm (t =. 3 sec) when excited with 340 or 356 nm radiation. 

The observed luminescence properties of the copolymer yarns can be easily explained if an energy transfer mechanism is assumed to be operating (Figure 7). Triplet-triplet energy transfer from the terephthalate units to the 4,4 -biphenyl -dicarboxyl ate units explains both the dual fluorescent/phospho-rescent emissions from the 4,4 -biphenyldicarboxyl ate units as well as the quenched phosphorescence from the terephthalate units. 

Figure 7. Electronic energy level diagram and transitions for polyfethylene tereph-thalate-co-4,4 -biphenyldicarboxylate) yarn (33)...

CHDM copolyesters containing residues of 2,6-naphthalenedicarboxylate, 4,4 -biphenyldicarboxylic acid and CHDM are reported to exhibit high heat resistance [91]. 

In the crystal structure of Zn3(OH)2(BPDC)2 (DEF)4(H20)2 where BPDC = 4,4 -biphenyldicarboxylate (MOF-69A), there are tetrahedral and octahedral Zn(II) centers coordinated by four and two carboxylate groups, respectively,... 

Physical properties are related to ester-segment structure and concentration in thermoplastic polyether-ester elastomers prepared hy melt transesterification of poly(tetra-methylene ether) glycol with various diols and aromatic diesters. Diols used were 1,4-benzenedimethanol, 1,4-cyclo-hexanedimethanol, and the linear, aliphatic a,m-diols from ethylene glycol to 1,10-decane-diol. Esters used were terephthalate, isophthalate, 4,4 -biphenyldicarboxylate, 2,6-naphthalenedicarboxylate, and m-terphenyl-4,4"-dicarboxyl-ate. Ester-segment structure was found to affect many copolymer properties including ease of synthesis, molecular weight obtained, crystallization rate, elastic recovery, and tensile and tear strengths. 

Alkylene 4,4 -Biphenyldicarboxylate/PTME 4,4 -Biphenyldicarbox-ylate Copolymers. Tetramethylene 4,4 -biphenyldicarboxylate/PTME 4,4 -biphenyldicarboxylate copolymers containing 20 and 30% tetra-methylene 4,4 -biphenyldicarboxylate were prepared without incident (Table VI). Attempts to prepare similar copolymers containing 40 and 50% tetramethylene 4,4 -biphenyldicarboxylate led to problems with phase separation in the melt during the copolymerizations. 

Fifty percent 4,4 -biphenyldicarboxylate/PTME 4,4 -biphenyldicar-boxylate copolymers were prepared using 1,3-propanediol (3G), 1,5-pentanediol (5G), and 1,6-hexanediol (6G) (Table VII). All were prepared without incident. The 3G-based copolymer has poor tear strength. The 5G-based copolymer has good tear strength but low tensile strength at break. The 6G-based copolymer has the best tensile strength of the three copolymers but has low tear strength. 

Table VI. Tetramethylene 4,4 -Biphenyldicarboxylate/PTME 4,4 -Biphenyldicarboxylate Copolymers—Properties as a Function of Tetramethylene 4,4 -Biphenyldicar-boxylate Concentration...

All of the isophthalate-based polyether-ester copolymers which were prepared using various diols are slow to crystallize. Those copolymers that eventually do crystallize exhibit excellent tensile strength and tear strength. All of the 2,6-naphthalenedicarboxylate copolymers prepared using linear ,o>-diols exhibit excellent tensile strength and tear strength. Phase separation in the melt is encountered with 4,4 -biphenyldicarboxyl-ate-based copolymer at the 50-wt % ester level when 1,4-butanediol is used as the diol monomer but not when 1,3-propanediol, 1,5-pentanediol, and 1,6-hexanediol are used. 

Reactions that involve cis-protected Mo2(DAniF)2 units have led to a variety of square structures with dicarboxylate anions. The linkers that have been used are oxalate (121), fumarate (122), ferrocenedicarboxylate (123) and 4,4 -biphenyldicarboxylate (124). The midpoints of the M02 units constitute a square, and their structures have been confirmed by H NMR spectroscopy and X-ray studies. Similar molecular squares containing Rh2 + units have been prepared with linkers such as oxalates (120), bicyclo[l.l.l]pentane-1,3-dicarboxylate (125), tetrafluoroterephthalate (126), 1,4-cubanedicarbboxylate (127), terephthalate (128), fumarate (129) and trans 1,4-cyclohexanedicarboxylate (130). The structures of these molecules have been established by spectroscopic and single-crystal diffraction studies. Detailed electrochemical investigations of these complexes have also been undertaken. ... 

Tb(bpdc)i, 5(H20)] 0.5 DMF was synthesized by diffusion of triethylamine into a mixture of Tb(N03 )3 H20 and 4,4 -biphenyldicarboxylic acid (H2bpdc) (molar ratio 2 1) in a mixture of DMF and EtOH at 4°C then at 55" C [75]. Its crystal structure is shown in Figure 3.16a. The terbium atom is coordinated with six oxygen atoms from six bpdc and one oxygen atom from a terminal aqua ligand, CN = 7. The crystallographically equivalent Tb(III) ions... 

Polyesters of 4,4 -Biphenyldicarboxylic Acid and Aliphatic Glycols for High-Performance... 

The dicarboxylic acid was obtained in 65% yield with 79% selectivity. Fortunately, there are better ways (see Chap. 6) to make this compound without the use of toxic carbon tetrachloride. This method gives 100% selectivity at 71% conversion in the reaction of biphenyl-4-carboxylic acid to form the 4,4 -biphenyldicarboxylic acid. /3-Cyclodextrin accelerates the platinum-catalyzed addition of triethoxysilane to styrene.231 The reaction is 100% complete in 30 min at 50°C with the cyclodextrin, but only 45% complete without it. The Wacker reaction of 1-decene produces several ketones owing to double-bond isomerization. If the reaction is run in a dimethylcyclodextrin, isomerization is reduced by faster reoxidation of palladium(O).232 The product 2-decanone is obtained with 98-99% selectivity (5.57). 

A new class of diamine spacer was synthesised from a,co-diaminoalkanes and 4-nitrophthalic anhydride the resulting a, -bis(4-aminophthalimido)alkanes were polycondensed with one of the following acid chlorides terephthaloylchlo-ride, 2-phenylthioterephthaloylchloride, naphthalene-2,6-dicarboxylic acid or 4,4 -biphenyldicarboxylic acid chloride [40]. Thermotropic behaviour was con-... 

Preparation of the starting material DIPB is typically achieved by isopropylation of benzene or cumene by use of conventional Friedel-Crafts catalysts [8] although solid acids [9], resins [10] and, more recently, zeolites [11,12] have also been mentioned as catalysts. Likewise, alkylation of polynuclear aromatics, e. g. biphenyl or naphthalene, gives rise to valuable intermediates. 4,4 -DialkyIbiphenyl can be converted into 4,4 -biphenyldicarboxylic acid, a monomer for a variety of... 

Free radical mechanisms have been proposed for this reaction [61, 72], and 4,4 -biphenyldicarboxylic acid, 2,4, 5-biphenyltricarboxylic acid, and l,2-bis(4-carboxyphenyl)ethane have been detected as side products [72]. The formation of chromophores is also enhanced by the presence of oxygen, as discussed below in Section 2.7. 

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