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31.
There is an investigation of the influences of the type and concentration of modifier (bis(2-hydroxyethyl)phosphite or the sodium salt of diethylphosphite) on the transesterification processes during polyethyleneterephthalate formation, as well as on the properties of the pre-condensation mixture. The rates of the side-reactions caused by the modifier are found to decrease when the sodium salt of diethylphosphite is employed. The characteristics of the pre-condensation mixture are close to those obtained with modifier-free mixtures. 相似文献
32.
Transesterification of dimethylphosphite (DMP) with diols yields the tri-functional bis(ω-hydroxyalkyl)phosphites. Phosphorus-containing polyurethanes are obtained by adding the latter to toluene- and hexamethylenediisocyanate. 相似文献
33.
The effect of disodium 1,2-dicarbomethoxyethylphosphonate on the polycondensation stage is studied. It is found that the polycondensation stage proceeds normally at 1–9% (by weight) of the combined dimethylterephthalate and ethylene glycol weights. The phosphorus-containing polyethyleneterephthalate obtained showed improved resistance to combustion and better thermal stability. 相似文献
34.
K. Troev E. Tashev G. Borisov 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3):313-318
Abstract The transesterification process of dimethyl and diethyl phosphite with 1,3-dichloropropanol-2 is examined. It is found that the reaction proceeds in the absence of catalyst at a temperature of 155°, whereas in the presence of morpholine as a catalyst it takes place at 126°C. The transesterification of dimethyl phosphite and diethyl phosphite with 1,3-dichloropropanol-2 is accompanied by the evolution of dimethyl and diethyl ethers and alkyl halides (methyl chloride and ethyl chloride). 相似文献
35.
Emilia D. Naydenova Petar T. Todorov Kolio D. Troev 《Phosphorus, sulfur, and silicon and the related elements》2013,188(7):1315-1320
A series of new cycloalkanespiro-5-hydantoin phosphonic acids have been synthesized and characterized. The mixture of [(2,4-dioxo-1,3-diazaspiro-alkane-3-yl)-methyl]phosphonic acids and [(2,4-dioxo-1,3-diazaspiro-alkane-1,3-diyl)dimethyl]diphospho-nic acids was obtained from cycloalkanespiro-5-hydantoins, formaldehyde, and phosphorus trichloride in a molar ratio of 1:2:2, by a procedure modified by us. Their structures were proved by means of IR, 1H, 13C{1H} and 31P NMR spectroscopy. 相似文献
36.
Violeta Mitova Georgi Grancharov Carolina Molero Ana M. Borreguero Kolio Troev Juan F. Rodriguez 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(7):774-795
A review of the research efforts on the development of pathways for the degradation of polymer–wastes of polyurethanes, polycarbonates and polyamides by esters of H-phosphonic and phosphoric acids is presented. Our group has made it clear, thanks to a vast research program devoted to this subject, that alkyl esters of H-phosphonic and phosphoric acids can be used as very effective degrading agents for polymers. Products and mechanism of polyurethanes degradation by treatment with phosphonates are reviewed in this work. The interest of phosphorus-containing degradation products lies on the fire retardant properties that these phosphorous moieties introduce in the recovered molecules. Most of these phosphorilated molecules can be easily reapplied as reactive intermediates by treatment with propylene oxide and used for the preparation of rigid polyurethane foams. The interaction of poly[2,2-bis(4-hydroxyphenyl)-propanecarbonate] (PC) with H-phosphonic acid dialkyl esters [(RO)2P(O)H, where R = CH3 or CH2CH3], or with triethyl phosphate (CH3CH2O)3P(O) yielded interesting phosphorus-containing oligocarbonates. Polyamide-6 can be converted into functional reactive oligomers with new properties by treatment with diesters of the H-phosphonic acid. 相似文献
37.
It was found that the reaction of dimethyl H‐phosphonate ( 1 ) with 2‐hydroxyalkyl‐N‐2′‐hydroxyalkyl carbamates at 135°C includes several chemical reaction steps: (i) chemical transformations of 1‐methyl‐2‐hydroxyethyl‐N‐2′‐hydroxyethyl carbamate ( 2 ) and 2‐methyl‐2‐hydroxyethyl‐N‐2′‐hydroxyethyl carbamate ( 3 ); (ii) transesterification of dimethyl H‐phosphonate with 2 and 3 , and with secondary hydroxyl‐containing compounds that are formed during the course of the chemical transformation of 2‐hydroxyalkyl‐N‐2′‐hydroxyalkyl carbamates; (iii) hydrolysis of 1 and dialkyl H‐phosphonates, formed via transesterification of 1 with secondary hydroxyl‐containing compounds. The interaction was studied by means of 1H, 13C, 31P NMR, and FAB mass spectroscopy. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:119–124, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20404 相似文献