Transformation of phthalic acid diesters in an anaerobic/anoxic/oxic leachate treatment process

Transformations of di-n-butyl phthalate(DBP) and di(2-ethylhexyl) phthalate(DEHP) have been investigated in anaerobic/anoxic/oxic(A/A/O) leachate treatment processes. Although the DBP removal processes are different when the DBP initial concentration is different, the overall system DBP removal efficiencies are high(N 94%).DEHP is much more difficult to remove than DBP. The removal efficiency of DEHP is approximately 75%–78%.The results of mass balance calculations indicate that approximately 33.7%–50.7% of the DBP is degraded by the activated sludge, 48.9%–64.9% accumulates in the system, and 0.4%–1.4% is contained in the final effluent. Approximately 15.0%–19.0% of the DEHP is degraded by activated microcosms, 75.8%–79.0% accumulates in the system, and 5.2%–6.0% is contained in the final effluent. Biodegradation and adsorption to the activated sludge are the main mechanisms for DBP removal and adsorption to the activated sludge is the main mechanism for DEHP removal. The different removal mechanisms of the two PAEs may be related to their different molecular structures. However, PAEs are not really removed when they adsorb onto the sludge. Therefore, methods for decreasing PAEs adsorption and increasing the biodegradation efficiencies of the leachate treatment processes should be further investigated.

An Unusual Acceleration of Amination Reactivity by the Proximal Ester Groups in Catechol Diesters: An Efficient Way for Peptide Synthesis

Peptide bond formation has drawn more and more attention due to its importance in medicinal chemistry and drug discovery.Using active esters to construct peptide bonds is an indispensable strategy in this field.We herein report a fast and efficient amination reaction to synthesize peptides from catechol diesters.Catechol monoesters are good active esters in peptide synthesis due to the anchimeric assistance effect.In previously reported work,the amination reaction was inactivated if the 2-hydroxyl group in the catechol esters was functionalized.However,we found an unusual acceleration of the amination reactivity when the 2-hydroxyl group was functionalized as an ester group.The reaction can be complete in 2−3 min in some cases.This acceleration was found through experimental studies to not result from the anchimeric assistance effect.We proposed aπ*−π*interaction pathway between the two proximal ester groups.Some computational studies were made to support this assumption.

Dichloromethane as a methylene synthon for regioselective linkage of diverse carboxylic acids:Direct access to methylene diesters under metal-free conditions

A metal-free cross coupling between common CH2Cl2 and carboxylic acids has been achieved with K2CO3 as the sole additive. This simple protocol is a convenient and cost-effective route to synthesize methylene diesters from a wide scope of carboxylic acids substrates with good functional group tolerance. Several gram-scale reactions have been performed to evaluate the effectiveness and practicality of this protocol.

Chemoselective synthesis of novel aminoindolizines using aminopyridines, acetylenic diesters and α-halo ketones

A chemoselective synthesis of novel indolizine derivatives were reported via three-component reactions of aminopyridines, acetylenic diesters and a-halo ketones. In these reactions, the zwitterion generated from aminopyridines and acetylenic diesters reacted with a-halo ketones to produce indolizine skeleton in good to high yields under mild reaction conditions.

Aggregation of deuteroporphyrin IX diesters in aqueous-organic binary solution

The aggregation properties of a series of deuteroporphyrin IX diesters in the THF-Buffer (0.1 mol·L?l Tris-HCl) aquiorgano solvent have been studied by means of UV-Vis and fluorescence spectrometers. Experimental data show that the dimerization of porphyrins is mainly determined by π-π interaction in pure organic solution while further aggregation of porphyrins with long hydro-carbon chains is more likely driven by hydrophobic-lipophilic interaction in aqueous-organic binary solution. The appearance of the aggregates induces a red shift in absorption spectra and fluorescence quenching in fluorescence spectra. The chain-length effect and chain-foldability effect have also been observed.

Lipophilicity determination of N-( benzothiazol-2-yl )-α-amino alkyl phosphonic diesters by RP-HPLC and RP-HPTLC

Using methanol-water mixtures as the mobile phase, the chromatographic retention parameters k' and Rf were determined by reversed-phase high-performance liquid chromatography (RP-HPLC) and reversed-phase high-performance thin-layer chromatography (RP-HPTLC) for N-(benzothiazol-2-yl)-α-amino alkyl phosphoric diesters and the correlation with lipophilicity parameter (Clog P) was established. Log Kw values obtained from RP-HPLC and Rm values obtained from RP-HPTLC can be used to evaluate the lipophilicity of this kind of compounds. Chromatographic method is a good alternative for lipophilicity measurement.

An Association of Elevated Serum Prolactin with Phthalate Exposure in Adult Men

Objective To investigate the associations of hormone circulation with phthalate exposure in adult men. Methods Semen and serum samples were collected from 118 men who were suspected of infertility. Phthalate diesters including dibutyl phthalate （DBP） and diethylhexyl phthalate （DEHP） in both semen and serum samples were measured, along with serum levels of follicle stimulating hormone （FSH）, luteinizing hormone （LH）, testosterone （T）, estradiol （E 2 ） and prolactin （PRL）. Results Serum PRL was positively associated with serum DBP and DEHP and semen DEHP in all models of Spearman correlation, linear regression and binary logistic regression. In linear regression models adjusted for potential confounders and excluding subjects with undetectable phthalates, a 10‐fold increase in semen DEHP was associated with a 23% increase in serum PRL, as well as a 26% increase in serum DBP and a 20% increase in serum DEHP. In logistic regression models all subjects demonstrated a dose‐response relationship between above reference value PRL and semen DEHP （odds ratio per tertile adjusted for potential confounders = 1.0, 1.70, 3.50; P for trend = 0.01）, and serum DBP （1.0, 1.10, 2.62; P for trend = 0.04）, and serum DEHP （1.0, 1.46, 4.69; P for trend 0.01）. A positive correlation between serum estradiol and semen DEHP （linear regression）, and an inverse correlation between semen DBP and serum testosterone and T：E 2 ratio （Spearman correlation） were also established. Conclusions Serum PRL is suggested to be positively associated with both DBP and DEHP exposure in adult men.

Synthesis and Properties of Novel Cationic Maleic Diester Polymerizable Surfactants

Three new cationic polymerizable surfactants are synthesized by the reaction of alkylmaleic hemiester with glycidyltrimethylammonium chloride. Their structures are confirmed by H-1 NMR, IR and elements analysis. The values of CMC and gamma (CMC) of these surfactants have been measured. One can obtain nearly monodisperse polystyrene latex by emulsion polymerization using the polymerizable surfactant.

Comparison of the Digestion and Absorption Characteristics of Docosahexaenoic Acid-Acylated Astaxanthin Monoester and Diester in Mice

Docosahexaenoic acid-acylated astaxanthin(DHA-AST)esters exhibit distinct bioactivities in improving brain function.However,the digestion and absorption characteristics of DHA-AST esters in vivo are unclear,thereby restricting the molecular mechanism analysis of their superior activities.This study compared the digestion and absorption characteristics of DHA-AST monoester and diester by determining the levels of AST and DHA in the serum,liver,small intestinal content and wall,and feces at different time points after a single-dose oral administration of the esters.After oral gavage with 2 mg AST equivalent of the DHA-AST monoester and diester for 18 h,the excretion rates were approximately 51%and 84%,respectively.This result indicates that DHA-AST monoester was better than diester for the absorption of AST.The results in serum,liver,and small intestinal content and wall also agreed with this finding.Moreover,the excretion rates of DHA in the feces at 24 h in the DHA-AST monoester and diester groups were approximately 40%and 36%after gavage with 5 mg DHA equivalent,respectively.This result indicates that DHA-AST diester exhibited a better tendency than monoester for the absorption of DHA.Interestingly,the results in the liver and small intestinal wall showed an apparent difference,indicating that DHA-AST diester was better than monoester for the absorption of DHA.These findings provide a scientific basis for the molecular mechanism analysis and utilization of DHA-AST monoester and diester as functional ingredients.

Phosphate Diester Hydrolysis by Dinuclear Tb(III) Complexes with BDBPH in Second-order Dependence

The kinetic study on the hydrolysis reaction of bis（4-nitrophenyl） phosphate （BNPP） catalyzed by Tb-BDBPH system（2：1） was carried out in 50% ethanol solution （pH 7.0-10.0） at 35℃ with I=0.10NaNO3. The second-order rate constant kBNPP, 2.3×10.3 （mol^-1L S^-1）, was determined. The dinuclear monohydroxo species, L-2Tb-OH, is kinetically mainly active species. The hydrolysis rate of BNPP by the complex is increased almost 2.6 million-fold compared with the background hydroxide rate at the same condition.

Aqueous Diels-Alder Reactions of Cyclopentadicnc with Symmetric Diester of Fumarate or Maleate

Symmetric, diesters of cis- or trans- bicyclo[2,2,1]hept-5-ene-2,3-dicarboxylate were prepared by aqueous Diels-Alder reaction of cyclopentadiene with symmetric diester of fumarate or maleate.

使用多相催化剂生产生物柴油

Diester工业公司在法国塞特建设生产脂肪酸甲酯(FAME)的新装置，160kt／a的装置将于2005年底投产，这将是采用Axens公司Esterfip-H工艺的第一套工业化装置。该装置的建设符合欧盟指令2003／EC3117目标要求，即到2010年使生物燃料用量达到5．75％，生物燃料可减少温室气体总排放量和使欧盟减小对原油进口的依赖。

A Facile Synthesis of N-Substituted Spirocyclic Diester of α-Aminophosphonic Acid

A simple and direct method for preparation of N-substituted spirocyclic dieSter of □-amino phosphonic acid (4) in high yield is introduced. The reaction consists of the threecomponent reachon of phenylurea (1), an aromatic aldehyde (2), and 3,9-dichloro-2,4,8,10-tetraoxa- 3, 9 -diphosphaspiro [5,5] undecane (3) in anhydrous benzene.

Reconstruction of Cu-ZnO catalyst by organic acid and deactivation mechanism in liquid-phase hydrogenation of dimethyl succinate to 1,4-butanediol

A reconstructed Cu-ZnO catalyst with improved stability was fabricated by organic acid treatment method for the liquid-phase hydrogenation of dimethyl succinate to 1,4-butanediol.According to the characterization results of the fresh Cu-ZnO and reconstructed Cu-ZnO,three different forms of ZnO were suggested to be presented on the catalysts:ZnO having strong interaction with Cu species,ZnO that weakly interacted with Cu species and isolated ZnO.The first form of ZnO was believed to be beneficial to the formation of efficient active site Cu^(+),while the latter two forms of ZnO took the main responsibility for the deactivation of Cu-ZnO catalysts in the liquid-phase hydrogenation of diesters.The reconstruction of the Cu-ZnO catalyst by the organic acid treatment method resulted in a new Cu-ZnO catalyst with more Cu^(+)and less ZnO species that leads to deactivation.Furthermore,the deactivation mechanism of Cu-ZnO catalysts in liquid-phase diester hydrogenation in continuous flow system was proposed:the deposition of the polyesters on the catalysts via transesterification catalyzed by weakly interacted ZnO and isolated ZnO leads to the deactivation.These results provided meaningful instructions for designing highly efficient Cu-Zn catalysts for similar ester hydrogenation systems.

Microwave-assisted,facile,rapid and solvent-free one pot two-component synthesis of some special acylals

A facile, rapid and solvent-flee method for the conversion of acids and dihalomethane to the corresponding methylene diesters （acylals） using microwave as activators or assistor, is reported. This method is particularly powerful for the diesterification of carboxylic acids, which afford methylene diesters in good to excellent yields （up to 〉99%）. When the intermediate is trapped, a ＂double successive SN2 reactions＂ mechanism is proved.