Reference

Reaction kinetics of the model reaction of benzoic acid with ethylene carbonate

Reaction kinetics of the model reaction of benzoic acid with ethylene carbonate. Fagerburg, David R. (Res. Lab., Eastman Kodak Co., Kingsport, TN 37662, USA). J. Macromol. Sci., Chem., A21(2), 141-54 (English) 1984. CODEN: JMCHBD.There are some reagents with their cas registry numbers 665-46-3 and 96-49-1 are used in this study. ISSN: 0022-233X. DOCUMENT TYPE: Journal CA Section: 35 (Chemistry of Synthetic High Polymers) Section cross-reference(s): 22 As a model for polymn., the reaction kinetics of BzOH [65-85-0] with ethylene carbonate (I) [96-49-1] were examd. in which various tetraethylammonium halides were used as catalysts. The salt anion appeared to have little or no effect on the rate of reaction. At a 1:1 BzOH-I mol ratio, reaction was zero-order to ~95% reaction. With Et4NOH [77-98-5] catalyst at 0.4 mol% (based on I), the activation energy was 20.8 kcal/mol with preexponential factor ln A = 17.1 (activation entropy -26 cal/deg). The activation energy for decompn. of I alone was 33 kcal/mol with preexponential factor ln A = 27.3. This ruled out previously suggested mechanisms that essentially involved decompn. of I prior to esterification. The proposed mechanism for the reaction involved the attack of the quaternary salt carboxylate on the methylene carbon of I. The attack caused ring opening and was followed by proton transfer and CO2 loss from the I half-ester intermediate. Ether linkages (such as diethylene glycol) were postulated to arise from the resultant alkoxide intermediate prior to protonation to give the hydroxyethyl ester rather than by sep. postreaction of I with the hydroxyethyl ester. .

Copolymerization of hydroquinone-styrene and epoxy-dihydroxydiphenylpropane oligomers

Copolymerization of hydroquinone-styrene and epoxy-dihydroxydiphenylpropane oligomers. Ragimov, A.Several substances are used for example 25068-38-6 and 89526-53-4 which are their cas registry numbers. V.; Seiidov, M. A.; Nagiev, A. Yu.; Liogon'kii, B. I.; Tairov, T. I. (USSR). Zh. Prikl. Khim. (Leningrad), 57(1), 128-32 (Russian) 1984. CODEN: ZPKHAB. ISSN: 0044-4618. DOCUMENT TYPE: Journal CA Section: 37 (Plastics Manufacture and Processing) The 2nd order rate consts. for crosslinking of epoxy resin ED-22 [25068-38-6] with p-benzoquinone-styrene copolymer [51541-22-1], contg. repeating units (I), at equimol. epoxy-hydroxyl group ratio, depending on the nature of the crosslinking catalyst and at 373-393 K, were 0.030-0.075 L kg-1 min-1 in the presence of Et4N+OH- [77-98-5] and 0.098-0.410 L kg-1 min-1 in the presence of Et3N×BuOH complex [13624-65-2]. The corresponding activation energies were 61.4 and 47.9 kJ/mol. The conversion of epoxy groups in presence of these catalysts was low, and even at 403 K after 15 h was ￡65%. The use of KOH as the crosslinking catalyst (concn. 0.5-2.0%) gave higher conversions of epoxy groups: 80% at 403 K in 1 h and 93% at 473 K in 20 min. The crosslinked copolymer [89526-53-4] obtained in the presence of 2% KOH had high softening temp., hardness, adhesive strength, and good dielec. properties. .