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1.
Functional zinc(II) phthalocyanines bearing Schiff base complexes as oxidation catalysts for bleaching systems
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Oxidation catalysis is used to increase the performance of hydrogen peroxide in laundry bleach applications. Bleach catalysts provide cost‐effective, energy‐saving and environmentally friendly bleach systems yielding perfect stain removal at lower temperatures. This comparative study is based on the synthesis of bis[bis(salicylhydrazonephenoxy)manganese(III)] phthalocyaninatozinc(II) ( 2 ), bis[bis(salicylhydrazonephenoxy)cobalt(III)] phthalocyaninatozinc(II) ( 3 ) and bis[bis(salicylhydrazonephenoxy)iron(III)] phthalocyaninatozinc(II) ( 4 ) as tri‐nuclear complexes consisting of two Schiff base complexes substituting a zinc phthalocyanine. Complexion on the periphery to obtain complexes 2 , 3 , 4 was performed through the reaction of a Schiff base‐substituted phthalocyanine using MnCl2?4H2O, CoCl2?6H2O or FeCl3?6H2O salts in basic condition in dimethylformamide. Fourier transform infrared, 1H NMR, 13C NMR, UV–visible, inductively coupled plasma optical emission and mass spectra were applied to characterize the prepared compounds. The bleach performances of the three phthalocyanine compounds 2 , 3 , 4 were examined by the degradation of morin as hydrophilic dye. The degradation progress in the presence of catalysts 2 , 3 , 4 /H2O2 combination in aqueous solution was investigated using an online spectrophotometric method. It was found that the catalysts 2 , 3 , 4 exhibited better bleaching performance at 25 °C than tetraactylethylethylenediamine as bleach activator used in powder detergent formulations for stain removal. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
2.
Dilek Yildiz JeronimusP.A.J. vanBeeck MichelL. Riethmuller 《Particle & Particle Systems Characterization》2004,21(5):390-402
Two‐phase flows hold an interest in many areas of science and engineering. In the safety field, one such topic is the accidental release of flammable and toxic pressure‐liquefied gases. In case of such a release, a flashing vapor explosion takes place resulting in a very dense two‐phase cloud. If the released substance is flammable, this cloud can be combustible and can lead to deflagration or detonation. For understanding the source processes of flashing and risk assessment, data related to cloud characteristics (i.e. droplet size, velocity etc.) is needed especially in the near region of the release. Due to the non‐equilibrium nature of the near field regions accurate data measurement is not possible with intrusive techniques. Therefore, laser‐based optical techniques (like Particle Image Velocimetry (PIV), Particle Tracking Velocimetry and Sizing (PTVS), Phase Doppler Anemometry (PDA) etc.) present the only possibility to obtain information for particle diameter and velocity evolution in this harsh environment. 相似文献
3.
The effects of five polyethylene glycol (PEG) compounds of different molecular weight on the thermal stability of penicillin
G acylase (PGA) obtained from a mutant ofEscherichia coli ATCC 11105 have been investigated. The molecular weights of PEG compounds were 400, 4000, 6000, 10,000, and 15,000. The thermal
inactivation mechanisms of both native and PEG-containing PGA were considered to obey first order inactivation kinetics during
prolonged heat treatments. Optimal concentrations of PEGs at molecular weights of 400,4000, 6000,10,000, and 15,000 were found
to be 250,150,150,100, and 50 mM, respectively. The greatest enhancement of thermostability was observed with PEG 4000 and
PEG 6000, as a nearly 20-fold increase above 50°C. PGA showed almost the same temperature activity profile and optimal temperature
values both in the presence and absence of PEG. The addition of PEGs did not cause any change in the optimal temperature value
of PGA, but the parametersV
m
,K
m
, the activation energy, and thek
cat
values of enzyme were markedly decreased because of the mixed inhibition by PEG compounds. The type of inhibition was found
to be hyperbolic uncompetitive. 相似文献
4.
Dilek
zmen 《Fluid Phase Equilibria》2006,250(1-2):70-75
(Liquid + liquid) equilibrium (LLE) data for (water + propionic acid + solvent) were measured at T = 298.2 K and atmospheric pressure. The solvents were methyl isoamyl ketone (5-methyl-2-hexanone), ethyl isoamyl ketone (5-methyl-3-heptanone) and diisobutyl ketone. The tie-line data were correlated by means of the NRTL and UNIQUAC equation, and compared with results predicted by the UNIFAC method. A comparison of the extracting capabilities of the solvents was made with respect to distribution coefficients, separation factors, and solvent free selectivity bases. 相似文献
5.
A new Schiff base, N,N′-bis-(2-hydroxy-5-bromobenzyl)-2-hydroxy-1,3-diiminopropane, has been synthesized for the very sensitive
determination of iron(III) and iron(II) in natural water samples. It enabled a very selective and rapid method for iron determination
to be developed. The method has also been applied to total iron determination in sediment samples. In the preconcentration
system, the Schiff base reagent is mixed with the samples and chelates containing iron(III). The complexes are then adsorbed
on silica gel within a column system. Elution of the adsorbed chelate from the silica gel was performed with a small volume
of acetone containing 2.5% nitric acid. The iron is measured off-line by flame atomic absorption spectrometry. The method
can be applied to the preconcentration, separation and speciation of iron. The effects of parameters such as pH, sample flow
rate, eluent flow rate, foreign ions and ligand concentration have been investigated. The effect of humic acid that can produce
complexes with metal ions in natural systems has also been investigated. The results obtained indicate that the method is
not affected by the presence of up to 10 ppm humic acid, which would be a very high concentration to be present in natural
systems. The solid phase extraction method developed has been applied to the determination of iron in both natural water samples
and sediment samples. The LOD was found to be 0.17 mg L−1 when no preconcentration was used, although preconcentration factors of 100 could be achieved. The recovery values for spiked
samples were between 100 and 104%. The results were compared statistically with those from the standard 1,10 phenanthroline
method used for iron speciation in water systems. A Student’s t-test indicated no significant difference between the two methods. In addition, this method was applied to the analysis of
a certified sediment sample, LGC 6156. Generally, a 10-fold preconcentration factor was required for the analysis of natural
water samples. 相似文献
6.
A series of new ionic binuclear Pd(II) complexes supported by water‐soluble bis(α‐diimine) ligands were prepared and employed as catalysts for the palladium‐catalyzed Suzuki reaction in aqueous media. The binuclear nature of the complexes increased the reaction rate, while electronic and steric modification of the ligand frameworks had a remarkable influence upon the catalytic activity of the palladium complexes. The catalysts were shown to be homogeneous through mercury poisoning experiments and complexes could be recycled more than 10 times without loss of catalytic activity. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
7.
Efficient and modular syntheses of chiral 2-(2-hydroxyaryl)alcohols (HAROLs), novel 1,4-diols carrying one phenolic and one alcohol hydroxyl group, have been developed which led to generation of a small library of structurally diverse HAROLs in enantiomerically pure form. Of the different HAROLs examined, a HAROL based on the indan backbone exhibited the highest activity and enantioselectivity in the 1,2-addition of certain organometallic compounds to aldehydes in the presence of Ti(OiPr)4 (up to 97% y, 88% ee) and performed as a hydrogen-bond donor organocatalyst in the Morita-Baylis-Hillman reaction, promoted by trialkylphosphines. 相似文献
8.
9.
10.
The Ramanujan Journal - Answering a question of Erdös, Komlós proved in 1968 that almost all $$n\times n$$ Bernoulli matrices are nonsingular as $$n\rightarrow \infty $$ . In this paper,... 相似文献