Glycol carbonate

Resorcinol carboxylation with carbon dioxide leads to a mixture of 2,4-dihydroxyben2oic acid [89-86-1] (26) and 2,6-dihydroxyben2oic acid [303-07-1] (27) (116). The condensation of resorcinol with chloroform under basic conditions, in the presence of cyclodextrins, leads exclusively to 2,4-dihydroxyben2aldehyde [95-01-2] (28) (117). Finally, the synthesis of l,3-bis(2-hydroxyethoxy)ben2ene [102-40-9] (29) has been described with ethylene glycol carbonate in basic medium (118), in the presence of phosphines (119). Ethylene oxide, instead of ethyl glycol carbonate, can also be used (120). 

Table 1. Properties of Diallyl Glycol Carbonate Monomers...

Lipase CA catalyzed the polymerization of cyclic dicarbonates, cyclobis (hexamethylene carbonate) and cyclobis(diethylene glycol carbonate) to give the corresponding polycarbonates [105]. The enzymatic copolymerization of cyclobis(diethylene glycol carbonate) with DDL produced a random ester-carbonate copolymer. As to enzymatic synthesis of polycarbonates, reported were polycondensations of 1,3-propanediol divinyl dicarbonate with 1,3-propanediol [110], and of diphenyl carbonate with bisphenol-A [111]. 

It should additionally be noted that a number of the paths of the schemes above have received some confirmation in a number of literature reports dealing with the photolysis and photo-oxidation of other polyesters [32-35], Because these reports investigated poly(butylene terephthalate) (PBT), poly(ethylene naphthalate) and poly(butylene naphthalate), however, they may not have direct application to understanding of the processes involved in PET and PECT and so have not been discussed in this present chapter. All do contain support for the formation of radicals leading to CO and C02 evolution, as well as the hydrogen abstraction at glycolic carbons to form hydroperoxides which then decompose to form alkoxy radicals and the hydroxyl radical. These species then were postulated to undergo further reaction consistent with what we have proposed above. 

Fig. 2. Effect of KBr on the copolymerization of equimolar mixtures of ethylene glycol carbonate with phthalic anhydrite.54) (Reproduced by courtesy of Huthig and Wepf Verlag). 1 — conductivity at 120 °C 2 — reaction rate at 200 °C 3 — reaction rate at 180 °C...

Solvent polarity influences the rate of copolymerization. Thus with increasing dielectric constant of the solvent, the copolymerization rate rises as a result of the increase in the dissociation constants of the active species. The apparent rate constant for the copolymerization of 2-hydroxy-4-(2,3-epoxypropoxy)benzophenone with phthalic anhydride, initiated by hexadecyltrimethylammonium bromide56), increases from 4.65 x 10 4 s 1 in o-xylene to 6.84x 10 4 s-1 in nitrobenzene. Hilt et al.S4) proposed a suitable model illustrating the effect of solvent polarity in the copolymerization of phthalic anhydride with ethylene glycol carbonate in a mixture of nitrobenzene and trichlorobenzene (Table 4). With increasing fraction of the more polar nitrobenzene, the rate of copolymerization increases. 

Table 4. Reaction rates and dielectric constants of solvents and reaction mixtures for the copolymerization of ethylene glycol carbonate (0.1 mol) with phthalic anhydride (0.1 mol) in, 100 ml of solvent initiated with KC1 (0.001 mol-%) at 200 °C. 541 (Reproduced by courtesy of Hiithig and...

Glycol carbonates and glycol sulfites are also included they split off respective oxides and form epoxides in situ during copolymerization 54 ... 

Experimental results on the copolymerization of phthalic anhydride with ethylene glycol carbonate initiated by UC-labelled sodium benzoate (Table 5) or potassium benzoate show 4l,42,54) that the molecular weights of the copolymers formed decrease with increasing initiator concentration. 

Table 5. Concentration effect of t4C-la belled sodium benzoate on the molecular weight of the polyester prepared from phthalic anhydride and ethylene glycol carbonate after 10 hours at 200 °C...

In contrast to the copolymerization of cyclic carbonates, the molecular weights are lower in the epoxide copolymerization 6,41 43). We assume that this is due to the presence of proton donors in the reaction mixture. They occur as impurities in epoxides 19,20) or anhydrides, moisture in all components of the copolymerization system, or their presence is a consequence of the high rate of hydrolysis of cyclic anhydrides 21). Proton donors added to the monomer feed remarkably decrease the molecular weight42 even in the copolymerization of ethylene glycol carbonate at 200 °C. Under these conditions, when recyclization of phthalic acid takes place 64) and the released C02 can tear off moisture to the gas phase, the molecular weight Mv decreases without proton donors from 45200 to 7100 in the presence of 5% phthalic acid or ethylene glycol or to 9300 in the presence of 15% water42,54. ... 

Fractionation of polyesters, prepared from phthalic anhydride and ethylene glycol carbonate and initiated by sodium benzoate or by KC1 (Fig. 5) revealed a broad molecular weight distribution 42). This indicates a wide application of transfer reactions and participation of macromolecules in transfer reactions. 

Fig. 5. Integral and differential distribution curves of polyesters 421 (Reproduced by courtesy of Hiithig and Wepf Verlag.). (Equimolar mixture of ethylene glycol carbonate and phthalic anhydride, 1 mol- % KC1, 15 h at 180 °C, and 24 h at 200 °C.)...

The most commonly used diallyl monomer is diallyl diethylene glycol carbonate, DADC or CR 39, developed for preparing clear, colorless, abrasion- and heat-resistant polymers (Table 2.29). DADC is obtained by reaction of diethylene glycol bis(chloroformate) with allyl alcohol, or allyl-chloroformate and diethylene glycol. 

Solubility in water, 4 g/100 mL. Slightly soluble in alcohol, benzene, ethylene glycol, carbon tetrachloride, and dioxane sparingly soluble in ether and acetone. Sensitive to oxidation, moisture, and light liquefies upon loss of water of crystallization.2... 

Daneshvar M, Kim S, Gulari E (1990) High-pressure phase equilibria of polyethylene glycol-carbon dioxide systems. J Phys Chem 94(5) 2124—2128... 

Weidner E, Wiesmet V, Knez Z et al (1997) Phase equilibrium (solid-liquid-gas) in polyethylene glycol-carbon dioxide systems. J Supercrit Fluids 10(3) 139-147... 

Water absorption is less than 0.1wt% after 24 hours. However, PBT is not recommended for extended use in water or aqueous solutions above 52C (125F).112 PBT plastics are also intrinsically resistant to detergents, weak acids and bases, aliphatic hydrocarbons, fluorinated hydrocarbons, alcohols, ketones, ethylene glycol, carbon tetrachloride, oils, and fats at room temperature. They also exhibit good resistance to motor oil, gasoline, transmission fluids, and brake fluids at temperatures to 60C (HOF).113... 

UnPET [United Resource Recovery PolyEthylene Terephthalate] A process for recycling waste PET (polyethylene terephthalate). The PET is first hydrolyzed by hot aqueous alkali, and the product then undergoes five complex processes. The only products leaving the process are terephthalic acid, ethylene glycol, carbon dioxide, and water. Developed from 1996 by the United Resource Recovery Corporation, Spartanburg, SC, and operated on a large scale in Switzerland, Germany, and the United States. 

In presence of aluminium trichloride, phosgene reacts with ethylene dissolved in carbon disulphide, forming -chloro-propionic chloride as well as polymerisation products of ethylene. By the action of phosgene on ethylene glycol at ordinary temperatures, glycol carbonate is formed according to the equation ... 

Cyclic dicarbonates, cyclobis(hexamethylene carbonate) and cyclobis(diethylene glycol carbonate), were polymerized by lipase CA.188 The random ester-carbonate copolymers were enzymatically obtained from DDL-cyclobis(diethylene glycol carbonate) and lactides-TMC.189... 

Polymer mitrix Rav 7 S - polyallyl di glycol carbonate Specimen jilmvi 1cm. ihicbea I. it mm Application method. thermal transfer... 

The third type of reaction for polyester polyols synthesis is the ring opening polymerisation of cyclic esters, such as -caprolactone (reaction 8.4) or cyclic carbonates, such as ethylene glycol carbonate, propylene glycol carbonate, neopentyl glycol carbonate, etc., (reaction 8.5) initiated by diols (or polyols) and catalysed by specific catalysts [7, 16]. 

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