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21.
L. Ya. Zakharova F. G. Valeeva A. R. Ibragimova L. A. Kudryavtseva Yu. F. Zuev L. V. Avvakumova V. I. Kovalenko A. I. Konovalov 《Russian Chemical Bulletin》2007,56(1):62-69
The kinetics of alkaline hydrolysis of O-ethyl O-p-nitrophenyl chloromethylphosphonate in a sodium bis(2-ethylhexyl)sulfosuccinate—n-nonane—polyethylene glycol—water reverse micellar system was studied in a wide range of concentrations of the surfactant
and water. The sign of the catalytic effect of micelles is inverted in the presence of the polymer. A sharp change in the
apparent rate constant of hydrolysis of the phosphonate was found in a region of the temperature percolation threshold.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 60–67, January, 2007. 相似文献
22.
Ionization of esters of carboxylic acids RCOOR' (R = H, alkyl; R' = alkyl) within the air plasma of the Atmospheric Pressure Chemical Ionization (APCI) source occurs largely via H(+)-transfer and, to a minor extent, via NO(+) association. The protonated ester MH(+) is normally observed as M(2)H(+) and as higher aggregates (M(3)H(+), M(3)H(+)(H(2)O)) also at high source temperature. The behavior of M(2)H(+) upon collisional activation is consistent with the reported dissociation of proton-bound dimers to MH(+) species that, in turn, fragment according to the known paths of lowest energy. In addition, other important product ions form within the plasma, some in very high relative abundance, which are attributed to ion-molecule condensation reactions between neutral M and either MH(+) or M(2)H(+) resulting in the elimination of CO, R'OH, alkene from the alkoxy moiety of the ester and HCOOH. A general scheme is proposed to account for the experimental observations, which suggest that the encounter complex formed between MH(+) and M or between M(2)H(+) and M may either collisionally relax to the protonated dimer or trimer, respectively, or react via covalent bond forming and cleaving steps to eliminate stable neutral molecules. The proposed scheme is supported by both the observed concentration dependence and the temperature dependence of the products relative abundances within the plasma. Such reactions can be the dominant process, as in the case of formate esters. A second significant ionization route involves addition of NO(+) to form M(n)NO(+) (n = 1, 2, 3). An additional product corresponding to [M(2)NO(+) - CO(2)] is also observed with iso- and n-butyl formate esters. 相似文献
23.
24.
Fluoroalkylated 1,2,3-triketone 2-arylhydrazones and 2-arylhydrazono-3-oxo esters react variously with methylamine depending on the structure of the fluorinated substituent. 2-Arylhydrazono-1,3-dicarbonyl compounds having “short” fluoroalkyl substituents condense with methylamine at the carbonyl group attached to the non-fluorinated substituent whereas ones containing a lengthy polyfluoroalkyl substituent undergo haloformic cleavage as a result of the amine addition at the carbonyl group bearing such a substituent. The resulting 2-arylazo-3-(N-methyl)amino-1-polyfluoroket-2-en-1-ones and 1-(N-methyl)amino-2-arylhydrazono-3-fluoroalkyl-3-oxopropanamides have complexing properties, and they can bind to nickel(II) and copper(II) ions. Nickel chelates can be obtained by a three-component condensation of 2-arylhydrazono-1,3-dicarbonyl compounds and methylamine in the presence of nickel(II) cations. 相似文献
25.
Sunil B. Jadhav 《Tetrahedron letters》2007,48(14):2485-2487
A rapid, mild and high yielding method for the synthesis of methylthiomethyl esters is reported from the corresponding aliphatic, aromatic and unsaturated carboxylic acids under Swern oxidation conditions using dimethylsulfoxide, oxalyl chloride and triethylamine at low temperature. 相似文献
26.
Characteristic features of reactions involving esters of phosphorus-containing acids in highly organized media (micelles, liquid crystals, vesicles, and emulsions) are surveyed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 298–312, February, 1996. 相似文献
27.
Binyuan Liu Yang Li Boo-gyo Shin Li Zhang Weidong Yan 《Polymer Degradation and Stability》2007,92(5):868-875
The thermal properties and degradation behaviors of poly(norbornene-2,3-dicarboxylic acid dialkyl esters) (PNB-dialkyl esters) (alkyl = Me (PNB-Me), Et (PNB-Et), Pr (PNB-Pr), and Bu (PNB-Bu)) were investigated by thermogravimetric analysis (TGA) in dynamic conditions and by infrared (IR) spectroscopy. The PNB-dialkyl esters show good thermal stability up to 350 °C, and the thermal stability decreases in the order Me > Et > Pr > Bu with the increase in size of side chain. The effect of side-chain size on the thermal degradation behaviors of PNB-dialkyl esters is evidenced by one-step thermal degradation profile for PNB-Me while two-step thermal degradation profile for PNB-Et, PNB-Pr, and PNB-Bu. Transformation is deduced to undergo β-hydrogen elimination and formation of anhydride group in the first stage of thermal degradation reaction according to TGA and IR results for PNB-Et, PNB-Pr, and PNB-Bu. The apparent activation energy and thermal degradation model of PNB-dialkyl esters are estimated by means of Ozawa-Flynn-wall method and Phadnis-Deshpande method, respectively. 相似文献
28.
R. Dustan Myrex Gary M. Gray Young-Jin Wright Prakash C. Bharara Keith E. Branham 《European Polymer Journal》2003,39(6):1105-1115
Polymeric phosphonate esters are an interesting class of organophosphorus polymers because both the polymer backbone and phosphorus substituents can be modified. These polymers have been prepared by ring-opening polymerizations of cyclic phosphites, stoichiometric polycondensations of dimethyl phosphonate with diols in conjunction with diazomethane treatment and by transesterification of polyphosphonate oligomers. Our initial attempts to prepare high molecular weight polymeric phosphonate esters by the transesterification methods were unsuccessful. Results indicate that the reactions of dimethyl phosphonate with diols to form polyphosphonate oligomers with only methyl phosphonate end groups are plagued by a serious side reaction that forms phosphonic acid end groups. These end groups do not participate in the transesterification reaction and limit the molecular weights of the polymers that can be obtained. The phosphonic acid end groups can be converted into reactive methyl phosphonate end groups by treatment with diazomethane, however diazomethane is explosive and the polymerization is slow. An alternative route for the production of high molecular weight polymers is the transesterification of the 1,12-bis(methyl phosphonato)dodecane, formed by the reaction of excess dimethyl phosphonate and 1,12-dodecanediol, with a Na2CO3 promoter. This allows polymers with molecular weights of up to 4.5×104 to be prepared, and no phosphonic acid end groups are observed in these polymers. Thermal analyses of the poly(1,12-dodecamethylene phosphonate) have shown that this polymer has reasonable thermal stability (onset of thermal decomposition at 273 °C). This polymer also undergoes a cold crystallization process at 15 °C similar to that which has been observed in some polyesters, polyamides and elastomers. 相似文献
29.
疏水缔合型增稠剂聚(丙烯酰胺-丙烯酸高级酯)的合成及增稠性能研究 总被引:5,自引:0,他引:5
采用沉淀聚合法合成了聚(丙烯酰胺-丙烯酸十四酯),聚(丙烯酰胺-丙烯酸十六酯)和聚(丙烯酰胺-丙烯酸十八酯),重点讨论了共聚物中疏水基团数量及疏水基团链长对增稠性能的影响。采用凯达尔定氮法和动态热分析(DMTA)测定了共聚物的组成及玻璃化温度。 相似文献
30.
E. A. Dikusar N. G. Kozlov V. I. Potkin T. D. Zvereva A. P. Yuvchenko M. P. Bei N. V. Kovganko 《Chemistry of Natural Compounds》2006,42(5):539-542
Previously unreported esters 1b–20b were synthesized from natural terpene alcohols, sterols, plant phenols, and camphar oxime (1a–20a) by reaction with o-carborane-C-carboxylic acid chloride.
__________
Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 434–436, September–October, 2006. 相似文献