PCTAs production

PCT, PETG, PCTG and PCTAs can all be prepared readily via standard melt-phase poly condensation processes [34, 35], The diacid can be delivered via transesterification of the dimethyl esters or via direct esterification of the diacids. Numerous conventional catalyst and catalyst combinations can be employed. The use of a catalyst or catalyst combination is important for the manufacture of polyesters via the melt-phase process and has been well reported in the literature [36-41], Appropriate catalyst systems enable the production of polyesters with high processing rates and high molecular... 

A method originally developed for terpenoid type off-flavor compounds was used [35]. By this method a JH NMR spectrum could be measured reliably from ca. 5 pg of monoterpenoid compound collected directly in the NMR solvent by preparative GC. A thick-wall (5 mm o.d., 2 mm i.d.) sample tube instead of a standard NMR tube was selected for the measurements in order to decrease the solvent volume from 700 to 100 pi. CH2C12 was found to be a suitable medium, because its JH NMR signal is locked at 5.30 ppm from tetramethylsilane (TMS). TheTi NMR spectral interpretation was mainly based on the synthetic procedure used, symmetry considerations of possible products, and characteristic intra-aromatic couplings. More details on the NMR spectroscopy of PCDTs and PCTAs are reported elsewhere [29,30,32]. 

Sample PCTA Mw t gmol PCTA -SH ino. per chain [PCTA] % (wlw) Product Mw 1 gmol Product a... 

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