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.

Catalysis for the synthesis of methacrylic acid and methyl methacrylate

Abstract: Methyl methacrylate (MMA) is a specialty monomer for poly methyl methacrylate (PMMA) and the increasing demand for this monomer has motivated industry to develop clean technologies based on renewable resources. The dominant commercial process reacts acetone and hydrogen cyanide to MMA (ACH route) but the intermediates (hydrogen cyanide, and acetone cyanohydrin) are toxic and represent an environmental hazard. Esterification of methacrylic acid (MAA) to MMA is a compelling alternative together with ethylene, propylene, and isobutene/t-butanol as feedstocks. Partially oxidizing isobutane or 2-methyl-1,3-propanediol (2MPDO) over heteropolycompounds to MAA in a single-step is nascent technology to replace current processes. The focus of this review is on catalysts and their role in the development of processes herein described. Indeed, in some cases remarkable catalysts were studied that enabled considerable steps forward in both the advancement of catalysis science and establishing the basis for new technologies. An emblematic example is represented by Keggin-type heteropolycompounds with cesium and vanadium, which are promising catalysts to convert isobutane and 2MPDO to MAA. Renewable sources for the MMA or MAA route include acetone, isobutanol, ethanol, lactic, itaconic, and citric acids. End-of-life PMMA is expected to grow as a future source of MMA.

Formation of acetone from the OH radical‐ and O3‐initiated reactions of a series of monoterpenes

Abstract: The formation yields of acetone from the gas-phase reactions of the OH radical (in the presence of NO) and O3 with a series of monoterpenes have been measured at room temperature and atmospheric pressure of air. The acetone formation yields ranged from <2–3% for the OH radical reaction with limonene and the O3 reactions with limonene and α-phellandrene to 50% for the O3 reaction with terpinolene. Combining these acetone formation yields with literature estimates of emission rates of monoterpenes from vegetation leads to an estimate of acetone formation from the atmospheric photooxidation of monoterpenes of ∼10–11 Tg yr−1 globally, a significant fraction of the global acetone source strength of 40–60 Tg yr−1. Reaction mechanisms leading to acetone formation from these monoterpene reactions are discussed.

Novel Acetone Metabolism in a Propane-Utilizing Bacterium, Gordonia sp. Strain TY-5

Abstract: In the propane-utilizing bacterium Gordonia sp. strain TY-5, propane was shown to be oxidized to 2-propanol and then further oxidized to acetone. In this study, the subsequent metabolism of acetone was studied. Acetone-induced proteins were found in extracts of cells induced by acetone, and a gene cluster designated acmAB was cloned on the basis of the N-terminal amino acid sequences of acetone-induced proteins. The acmA and acmB genes encode a Baeyer-Villiger monooxygenase (BVMO) and esterase, respectively. The BVMO encoded by acmA was purified from acetone-induced cells of Gordonia sp. strain TY-5 and characterized. The BVMO exhibited NADPH-dependent oxidation activity for linear ketones (C3 to C10) and cyclic ketones (C4 to C8). Escherichia coli expressing the acmA gene oxidized acetone to methyl acetate, and E. coli expressing the acmB gene hydrolyzed methyl acetate. Northern blot analyses revealed that polycistronic transcription of the acmAB gene cluster was induced by propane, 2-propanol, and acetone. These results indicate that the acmAB gene products play an important role in the metabolism of acetone derived from propane oxidation and clarify the propane metabolism pathway of strain TY-5 (propane → 2-propanol → acetone → methyl acetate → acetic acid + methanol). This paper provides the first evidence for BVMO-dependent acetone metabolism.

Ethanol production by thermophilic bacteria: metabolic control of end product formation in Thermoanaerobium brockii.

Abstract: Specific changes in the chemical and microbial composition of Thermoanaerobium brockii fermentations were compared and related to alterations of process rates, end product yields, and growth parameters. Fermentation of starch as compared with glucose was associated with significant decreases in growth rate and intracellular fructose-1,6-bisphosphate concentration and with a dramatic increase in the ethanol/lactate product ratio. Glucose or pyruvate fermentation in the presence of acetone was correlated with increased substrate consumption, growth (both rate and yield), acetate yield, and quantitative reduction of acetone to isopropanol in lieu of normal reduced fermentation products (i.e., H2, ethanol, lactate). Acetone altered pyruvate phosphoroclastic activity of cell extracts in that H2, lactate, and ethanol levels decreased, whereas the acetate concentration increased. Glucose fermentation in the presence of exogenous hydrogen was associated with inhibition of endogenous H2 production and either increased ethanol/acetate product ratios and decreased growth at less than 0.5 atm (51 kPa) of H2 or total growth inhibition at 1.0 atm (102 kPA). The effects of exogenous hydrogen on glucose fermentation were totally reversed by the addition of acetone. Glucose fermentation in coculture with Methanobacterium thermoautotrophicum correlated with increased growth (both rate and yield), acetate yield, and the formation of methane in lieu of monoculture reduced products. In coculture, but not monoculture, T. brockii grew on ethanol as the energy source, and acetate and methane were the end products as a direct consequence of hydrogen consumption by the methanogen.