DISODIUM TEREPHTHALATE

Example 2. Reactor Experiment.66 Waste PET (110 g), 800 g of ethylene glycol, and 93 g of 50% aqueous sodium hydroxide were introduced into a reactor. The reaction mixture was heated to 170° C with agitation while collecting distillate (mostly water with some ethylene glycol). The slurry, which consisted of disodium terephthalate in ethylene glycol, was filtered at a temperature of 170° C in a vacuum filter. The disodium terephthalate obtained was pressed as dry as possible and the ethylene glycol was recovered. The filter cake was washed with room temperature EG to remove impurities and to cool the disodium terephthalate to less than 100° C, followed by washing with a saturated solution of disodium terephthalate in water (maintained at 90-100° C). 

The disodium terephthalate was dissolved in water (15 g of disodium terephthalate is soluble in 100 mL of cold water). The solution was filtered to remove any... 

PETP flakes produced from used soft drinks bottles were subjected to alkaline hydrolysis in aqueous sodium hydroxide. A phase transfer catalyst (trioctylmethylammonium bromide) was used to enable the depolymerisation reaction to take place at room temperature and under mild conditions. The effects of temperature, alkali concentration, PETP particle size, PETP concentration and catalyst to PETP ratio on the reaction kinetics were studied. The disodium terephthalate produced was treated with sulphuric to give terephthalic acid of high purity. A simple theoretical model was developed to describe the hydrolysis rate. 17 refs. 

While this is an effective nucleation mechanism for PET, the efficiency of this system is not stable and decreases significantly with melt mixing (compounding) time. This instability is due to a disproportion reaction in which the sodium chain ends react with each other to give disodium terephthalate. The subsequent decrease in ionic chain end concentration is directly linked to the loss in nucleation efficiency. 

Practical grade 2-(2-ethoxyethoxy)ethanol (Matheson, Coleman and Bell) can be used without further treatment. In a few preparations, the submitters encountered difficulty with the formation of a very stiff gel of disodium terephthalate in the flask during distillation. In one case, this difficulty was traced to the use of an old bottle of 2-(2-ethoxyethoxy)ethanol from another source. 

Fig. 10. Effect of inhibiting salts upon the hydrolysis of 2,6-dinitrophenyl phosphate in 3 X lO- MCTABat 25-0° and pH 9 0 A, sodium chloride .sodium methane sulfonate I. sodium P toluene sulfonate O. sodium benzoate . dipotassium phthalate o. disodium terephthalate disodium phenyl phosphate (Bunton et al., 1968).

The reaction between titanocene dichloride and salts of diacids were studied.181,183 The reactive species in both the aqueous solution and IF systems are believed to be R-C002 and Cp2Ti+2 with reaction occurring within the aqueous layer.181,183 The condensation of titanocene dichloride with disodium terephthalate in the IF systems occurs via a pseudo-first-order reaction R = k[Cp2TiCl2]... 

In recent years, several works have appeared on the alkali degradation of PET in solvents other than water. Thus, Collins and Zeronian56 have reported that treatment of PET with methanolic sodium hydroxide causes a faster degradation than when using aqueous sodium hydroxide. In the same way, Oku et al.51 converted PET quantitatively by reaction at 150°C with sodium hydroxide dissolved in anhydrous ethylene glycol. Disodium terephthalate was obtained as the major product, being precipitated from the ethylene glycol solution. Terephthalic acid was easily recovered by dissolution in water of the sodium salt followed by acidification with HC1. H-NMR measurements of the... 

Saponification Direct reaction of PET with alkali metal hydroxides is used to produce EG and, for example, disodium terephthalate (DNaTA). DNaTA may be recovered as-is or may be reacted with sulfuric acid to produce TA and sodium sulphate. If a market for the sodium sulfate is available, this can contribute to the process economics if it is simply a waste product, it will detract from the economics because the cost of disposal will need to be included in overall process costs. 

Phase transfer agents were chosen to give a broad representation of available agents. Typical results appear in Table 3. Addition of PTA s to the triethylamine systems typically led to lower yields and shorter chains except for 18-Crown-6 where the yield was the highest obtained, about double that obtained without the crown ether (Table 4). For the disodium terephthalate systems, addition of a PTA typically leads to a lowering of yield but a substantial increase in chain length when employing 15-Crown-5 (Table 5). 

Alkaline hydrolysis of PET was usually carried out with the use of an aqueous alkaline solution of NaOH, of a concentration of 4-20 wt.-%. The reaction products are EG and the disodium terephthalate salt. 

Tri-Nasal spray is a metered-dose manual-spray pump in an amber polyethylene terephthalate bottle with 0.05% w/v triamcinolone acetonide in a solution containing citric acid, edetate disodium, polyethylene glycol 3350, propy-... 

DSP Fibers. See Polyethylene terephthalate DSPP. See Sodium acid pyrophosphate DSS. See Disodium sebacate Dioctyl sodium sulfosuccinate... 

When the disodium salt of l,2-bis(methoxycarbonyl)ethane phosphonic acid is applied, poly(ethylene terephthalate) with the structure given below was obtained [93,94]. It was found that the polycondensation stage proceeds normally at 1-9% (by weight) of the... 

The reaction products are ethylene glycol and the disodium (or dipotassium) terephthalate salt (Scheme 4.9). 

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