No abstract

The reaction rates of CO2 in an aqueous blend of amine solutions of N‐(2‐hydroxethyl)piperazine (N‐HEPZ) and 2‐amino‐2‐hydroxymethyl‐1,3‐propanediol (AHPD) at 298 K were investigated in a concentration range of 0.0025–0.03 kmol m–3 N‐HEPZ with a blend of 1 kmol m–3 AHPD. The reaction was modeled using a termolecular reaction mechanism with a rate of 12 971 m3kmol–1s–1. The results indicate that the blended aqueous solution of N‐HEPZ and AHPD is a potential candidate as an alternative solvent for CO2 absorption, where the sterically hindered AHPD increases the CO2 capacity and the reaction rate is enhanced by the promoter, N‐HEPZ.

Current researchers from environmental and industrial fields are focusing on advanced means of carbon dioxide (CO 2 ) capture to limit its consequences in process industries. They also intend to enhance the mitigation of environmental impart by CO 2 especially its greenhouse effect. In this study, the kinetics of CO 2 reaction with an aqueous blend of piperazine (PZ) and 2-amino-2-ethyl-1,3-propanediol (AEPD) were investigated. It was found that blending of AEPD with a little percentage of PZ generated the observed rate constant, k o , values that were more than twice the direct summation of the k o values of the aqueous pure amines at the corresponding concentration and temperature. The kinetic study of the system was modeled using a termolecular mechanism. Blending 0.05 kmol/m 3 of PZ with 0.5 kmol/m 3 of AEPD gives an observed rate constant k o value of 2397.9 s −1 at 298 K. This result is comparable to rate constants of other amine mixtures. Thus, the aqueous blend of AEPD with PZ is an attractive solvent for CO 2 capture that has good advantages. The PZ that serves as the promoter in the reaction is needed in small fraction, whereas AEPD, which is a sterically hindered amine, increases CO 2 absorption capacity of the system. AEPD can be produced from renewable materials. C

A series of mixed ligand dithiocarbamate complexes with a general formula [ML2(py)2], where M = Mn(II), Co(II), Ni(II), and Cu(II), py = pyridine, and L = N-methyl-N-phenyl dithiocarbamate have been prepared and characterised by elemental analysis, FTIR and Uv spectroscopy, magnetic moment, and thermogravimetric and conductance analysis. The infrared spectra showed that symmetrical bidentate coordination occurred with the dithiocarbamate moiety through the sulfur atoms, while neutral monodentate coordination occurred through the nitrogen atom for the pyridine molecule in the complexes. The electronic spectra, elemental analysis, and magnetic moment results proved that the complexes adopted octahedral geometry. The conductance measurement showed that the complexes are nonelectrolytes proving their nonionic nature. The compounds were screened for three human pathogenic fungi: Aspergillus flavus, Aspergillus niger, and Candida albicans. The cobalt complex showed the best antifungal activity among the test compounds. Liquid-liquid extractive abilities of the ligand towards copper and nickel ions in different solvent media were investigated. The ligand showed a strong binding affinity towards the metals ions with an extractive efficiency of about 99%.

The continued use of fossil fuels as primary sources of energy in industry and other applications stands the test of time, due to their availability and relatively lower cost than alternative sources of energy. In view of this perspective, obtaining an advanced bulk carbon dioxide (CO2) capture medium becomes an urgent necessity so as to mitigate their effect, especially in global warming, as the use of fossil fuels produces a high rate of CO2. In this work, the mechanism and kinetics of CO2 capture using aqueous piperazine (PZ) as an activator to 2‐amino‐2‐methyl‐1,3‐propanediol (AMPD) were investigated. The termolecular mechanism was used to model the kinetics of the system. Reaction kinetics of the single pure amines was first obtained. The reaction rate constant, the k value of AMPD, was 77.2 m3/kmol·s, with a reaction order, n, of 1.25 at 298 K. while that of PZ was equal to 11,059 m3/kmol·s and n as 1.49 at 298 K. Blending of 0.05 kmol/m3 of PZ with 0.5 kmol/m3 of AMPD gave a rate constant, k, value of 23,319 m3/kmol·s and n equal to 1.23 at 298 K. The result obtained for the blended system is more than twice the value of the summation of the corresponding pure amines; in addition, it is comparably higher than the rate constant of monoethanolamine (MEA) in use as a commercial solvent for CO2 capture. Therefore, an aqueous blend of PZ with AMPD deserves more comprehensive study as a solvent for commercial CO2 capture. AMPD like other sterically hindered amines absorbs CO2 in an equimolar ratio that is significantly higher than that of MEA. PZ serves as a promoter in the amine mixture and is required in a very small proportion.