Acetone

About: Acetone is a research topic. Over the lifetime, 9458 publications have been published within this topic receiving 120867 citations. The topic is also known as: propanone & dimethylketone.

Preparation of nitrogen-containing carbon nanotubes and study of their performance as basic catalysts

Abstract: Nitrogen-containing carbon nanotubes were prepared, characterized and used as catalysts for two reactions of interest in the biomass upgrading processes: acetone aldol and acetic acid decarboxylative condensations. N-CNT were synthesized in a fluidized bed reactor by catalytic chemical vapor decomposition of acetonitrile on iron-, cobalt- and nickel-supported catalysts. Ni-N-CNT catalyst exhibits the highest activity, attributed to the surface concentration of basic sites, particularly the pyridinic species detected by X-ray photoelectron spectra (XPS). Likewise, the selectivity toward the final products of the reaction pathway is related both to the strength of basic sites (Ni-N-CNT) and to the morphology and chemical environment of the active sites (Fe-N-CNT). Synthesized catalysts show high stability for acetone condensation, whereas for ketonic condensation the catalyst stability decreases, mainly due to acic–base interactions with the active sites.

Development of Cellulose Acetate Membranes for Bacteria Immobilization to Remove Phenol

Abstract: The objective of this study is to investigate the feasibility of developing cellulose acetate (CA) membranes to partially immobilize Pseudomonas putida (ATCC 49451) and to evaluate the inhibitory effect of phenol on the immobilized bacteria by monitoring their growth in partially immobilized and free-suspension systems. The cellulose acetate membranes used in this study were wet spun from 20 wt % of CA in 1-methyl-2-pyrrolidone (NMP)/acetone (30 : 70) solvent using water as the bore fluid as well as the external coagulant. Scanning-electron microscopy (SEM) characterization of the newly developed CA hollow fibers suggests that the fiber cross section consists of multilayer microporous structures useful for cell immobilization. Experiments were conducted using the bacteria to degrade phenol at initial phenol concentrations of 300 mg/L and 1000 mg/L. In a free suspension (no membrane) system, it was observed that the bacteria were able to grow optimally at 300 mg/L of phenol, and degraded phenol almost completely in about 26 h. However, neither cell growth nor phenol degra- dation occurred when initial concentration of phenol was increased to 1000 mg/L. In a cell-immobilized membrane system, the cell growth and phenol concentration profiles in the medium were very similar to those obtained in a free suspension culture if phenol concentration was 300 mg/L. However, when the initial phenol concentration was increased to 1000 mg/L, data obtained in a cell-immobilized membrane system were discernibly different from that obtained in the suspension culture. In the former case, phenol concentration decreased in the beginning of test, indicating that the carbon source has been consumed and immobilized cells within the membrane had begun to multiply. As soon as the phenol concentration decreased to about 700 mg/L (at which concentration, substrate inhibition was not as severe as 1000 mg/L),partial immobili- zation occurred when some cells diffused out of the membrane into the medium and optical density became measurable in the medium. It was found that cell growth contin- ued for the next 32 h, reaching an optical density in the medium of 0.42 absorbance units and a significant amount of phenol was degraded. q 1998 John Wiley & Sons, Inc.

Spectrophotometric determinations of chloroplastidic pigments in acetone, ethanol and dimethylsulphoxide

Abstract: Spectrophotometric determinations of chloroplastidic pigments in acetone, ethanol and dimethylsulphoxide). The concentration of pigment indicates a range of properties in the physiological processes of plants. A large number of procedures have been developed to measure leaf pigment content. Some of these procedures involve leaf maceration and centrifugation, while others require incubation of a leaf sample in solvent for a few minutes or hours, which makes the process laborious. The choice of the best procedure may vary according to the plant species and type of solvent used. This study compared the efficiency of three commonly used solvents (dimethylsulphoxide, ethanol and acetone) in the extraction of chlorophylls and carotenoids of five plant species and one lichen species. The results indicated that dimethylsulphoxide was more efficient at chlorophyll extraction in all of the studied species. The ethanol and acetone extracts quickly lost molecular stability. Acetone extract may also cause phaeophytinisation and reduce the chlorophyll content.

Effect of the metallic/acid site (nPt/nA) ratio on the transformation of acetone towards methyl isobutyl ketone

Abstract: Methyl isobutyl ketone (MIBK) was synthesized from acetone (Ac) and hydrogen over Pt-HZSM5 bifunctional catalysts. The reaction was carried out at 160°C, atmospheric pressure, and with a PH2/PAc molar ratio = 0.33, using a fixed bed and dynamic flow reactor. The results show that catalytic properties and coke formation largely depend on the ratio between the number of accessible hydro-dehydrogenation sites and the number of theoretical acidic sites (nPt/nA).