Organic Acetic Acid Research Articles

Analysis of Acid Options in the Purification of Spent Motor Engine Oil Using Acidified Clay

Abstract: This research is centered on the purification of Spent Shell Helix (HX3 20W-50) lubricating oil using acidified clay treatment with three acids options: mineral sulfuric acid (H2SO4), organic acetic acid (CH3COOH), and organic citric acid (C6H8O7), (a novel washing agent). The clay mineral, spent, purified, and fresh lubrication oil samples were characterized to determine their physicochemical properties. The clay mineral was characterized using Energy-Dispersive X-Ray Fluorescence (EDXRF). The result indicated that the clay was bentonite clay and it was successfully acidified. The result also indicated that properties of the spent lubricating oil such as Kinematic viscosities at 40 oC and 100 oC increased from 118.9 cSt and 13.9 cSt for the spent oil to 169.7 cSt and 15.2 cSt, 178.2 cSt and 16.3 cSt, 183.4 cSt and 16.8 cSt for the oil samples purified with C6H8O7, CH3COOH and H2SO4 respectively Also, the flash point increased from 106 oC for the spent oil to 133 oC, 180 oC, 189 oC for the oil samples purified with C6H8O7, CH3COOH and H2SO4 respectively. The FTIR analysis of the spent oil revealed the presence of primary oxidized products, absent in spent engine oil purified with mineral sulphuric acid (H2SO4), organic acetic acid (CH3COOH), and fresh oil. Acidified clay effectively purified the spent engine oil, bringing its physicochemical properties closer to those of fresh oil. However, the effectiveness of the treatment varied depending on the specific acid used.

Variation of the properties of sol–gel synthesized bioactive glass 45S5 in organic and inorganic acid catalysts

Sol–gel synthesis of BG 45S5 using organic acetic acid as a catalyst was found to be superior to the conventional inorganic acid method.

Physicochemical and herbicidal properties of emulsions of essential oils against Avena fatua L. and Chenopodium album L.

Essential oils have herbicidal effects, which can potentially be improved by the addition of adjuvants. The present study evaluated (1) the stability and other physicochemical properties of peppermint and caraway oils in oil-in-water emulsions and mixtures with commercially available adjuvants and (2) the phytotoxic effects of the foliar application of peppermint and caraway oil emulsions and mixtures to Chenopodium album L. (common lamb’s quarters) and Avena fatua L. (wild oat). An investigation was conducted with two multifunctional adjuvants, two nonionic surfactants, and two mixture constituents, i.e., organic acetic acid (vinegar) and citric acid, to assess the physicochemical properties of emulsions and mixtures with essential oils. In addition, two series of greenhouse pot experiments were set up to evaluate the herbicidal effects of these emulsions and mixtures against two common weed species. None of the emulsions or mixtures under study exhibited satisfactory stability. The emulsions of both essential oils had a significant herbicidal effect against C. album. None of the adjuvants significantly improved the efficacy. On the other hand, the herbicidal effect of emulsions against A. fatua depended on the ambient temperature in the greenhouse with treatments more effective at higher temperatures. The multifunctional adjuvants AS 500 and Atpolan Bio enhanced the herbicidal effect of caraway oil against A. fatua over 2 weeks. Peppermint oil alone induced considerable short-term herbicidal effects. Some adjuvants improved the efficacy of peppermint oil shortly after application, but due to regrowth no significant effects on biomass were obtained at harvest. In summary, the addition of adjuvants can improve the herbicidal effects of caraway and peppermint oil; however, further research into these effects is warranted.

Ancient low–molecular-weight organic acids in permafrost fuel rapid carbon dioxide production upon thaw

Northern permafrost soils store a vast reservoir of carbon, nearly twice that of the present atmosphere. Current and projected climate warming threatens widespread thaw of these frozen, organic carbon (OC)-rich soils. Upon thaw, mobilized permafrost OC in dissolved and particulate forms can enter streams and rivers, which are important processors of OC and conduits for carbon dioxide (CO2) to the atmosphere. Here, we demonstrate that ancient dissolved organic carbon (DOC) leached from 35,800 y B.P. permafrost soils is rapidly mineralized to CO2. During 200-h experiments in a novel high-temporal-resolution bioreactor, DOC concentration decreased by an average of 53%, fueling a more than sevenfold increase in dissolved inorganic carbon (DIC) concentration. Eighty-seven percent of the DOC loss to microbial uptake was derived from the low-molecular-weight (LMW) organic acids acetate and butyrate. To our knowledge, our study is the first to directly quantify high CO2 production rates from permafrost-derived LMW DOC mineralization. The observed DOC loss rates are among the highest reported for permafrost carbon and demonstrate the potential importance of LMW DOC in driving the rapid metabolism of Pleistocene-age permafrost carbon upon thaw and the outgassing of CO2 to the atmosphere by soils and nearby inland waters.

In silico genome‐scale reconstruction and validation of the Corynebacterium glutamicum metabolic network

A genome-scale metabolic model of the Gram-positive bacteria Corynebacterium glutamicum ATCC 13032 was constructed comprising 446 reactions and 411 metabolites, based on the annotated genome and available biochemical information. The network was analyzed using constraint based methods. The model was extensively validated against published flux data, and flux distribution values were found to correlate well between simulations and experiments. The split pathway of the lysine synthesis pathway of C. glutamicum was investigated, and it was found that the direct dehydrogenase variant gave a higher lysine yield than the alternative succinyl pathway at high lysine production rates. The NADPH demand of the network was not found to be critical for lysine production until lysine yields exceeded 55% (mmol lysine (mmol glucose)(-1)). The model was validated during growth on the organic acids acetate and lactate. Comparable flux values between in silico model and experimental values were seen, although some differences in the phenotypic behavior between the model and the experimental data were observed.

Polyphosphate Kinase Protects Salmonella enterica from Weak Organic Acid Stress

Mutants of Salmonella enterica lacking polyphosphate kinase (ppk) grow poorly in the presence of the weak organic acids acetate, propionate, and benzoate. This sensitivity is corrected by methionine and seems to result from destabilization of MetA (homoserine transsuccinylase), the first enzyme in methionine biosynthesis. The MetA protein is known to be sensitive to thermal inactivation, and ppk mutants are more sensitive to heat-induced methionine auxotrophy. Peroxide increases the sensitivity of ppk mutants to both heat and acid and may oxidatively damage (carbonylate) destabilized MetA. While acid appears to impair methionine biosynthesis, it leads to derepression of MetA and may inhibit growth by causing toxic accumulation of denatured protein. This is supported by the observation that the overexpression of MetA in ppk mutants causes acid sensitivity that is not corrected by methionine. We propose that polyphosphate acts as a chemical chaperone that helps refold MetA and/or may stimulate proteolysis of toxic denatured protein. The instability of MetA protein may provide a metabolic fuse that blocks growth under conditions that denature proteins; the sensitivity of this fuse is modulated by polyphosphate.

Propionate oxidation by and methanol inhibition of anaerobic ammonium-oxidizing bacteria.

Anaerobic ammonium oxidation (anammox) is a recently discovered microbial pathway and a cost-effective way to remove ammonium from wastewater. Anammox bacteria have been described as obligate chemolithoautotrophs. However, many chemolithoautotrophs (i.e., nitrifiers) can use organic compounds as a supplementary carbon source. In this study, the effect of organic compounds on anammox bacteria was investigated. It was shown that alcohols inhibited anammox bacteria, while organic acids were converted by them. Methanol was the most potent inhibitor, leading to complete and irreversible loss of activity at concentrations as low as 0.5 mM. Of the organic acids acetate and propionate, propionate was consumed at a higher rate (0.8 nmol min(-1) mg of protein(-1)) by Percoll-purified anammox cells. Glucose, formate, and alanine had no effect on the anammox process. It was shown that propionate was oxidized mainly to CO(2), with nitrate and/or nitrite as the electron acceptor. The anammox bacteria carried out propionate oxidation simultaneously with anaerobic ammonium oxidation. In an anammox enrichment culture fed with propionate for 150 days, the relative amounts of anammox cells and denitrifiers did not change significantly over time, indicating that anammox bacteria could compete successfully with heterotrophic denitrifiers for propionate. In conclusion, this study shows that anammox bacteria have a more versatile metabolism than previously assumed.

Sulfur isotope fractionation during growth of sulfate-reducing bacteria on various carbon sources

Stable sulfur isotope fractionation during microbial sulfate reduction is a potential tool to estimate sulfate reduction rates at field sites. However, little is known about the influence of the utilized carbon source on the magnitude of sulfur isotope fractionation. To investigate this effect, both a pure culture (strain PRTOL1) and enrichment cultures from a petroleum hydrocarbon (PHC)–contaminated aquifer were used and grown in batch cultures on various carbon sources with an initial sulfate concentration of 1 mmol/L. As sole carbon sources the PHC components naphthalene, 1,3,5-trimethylbenzene, and heating oil (enrichment culture) and the organic acids acetate, pyruvate, benzoate, and 3-phenylpropionate (enrichment culture and PRTOL1) were used. Sulfate reduction rates of all cultures ranged from 6 ± 1 nmol cm −3 d −1 (enrichment culture grown on 1,3,5-trimethylbenzene) to 280 ± 6 nmol cm −3 d −1 (enrichment culture grown on pyruvate). Cell-specific sulfate reduction rates ranged from 1.1 × 10 −14 mol cell −1 d −1 (PRTOL1 grown on pyruvate) to 1.5 × 10 −13 mol cell −1 d −1 (PRTOL1 grown on acetate). Sulfur isotope enrichment factors (ε) for the enrichment culture ranged from 16.1‰ (3-phenylpropionate) to 34.5‰ (1,3,5-trimethylbenzene) and for PRTOL1 from 30.0‰ (benzoate) to 36.0‰ (pyruvate). Cultures of PRTOL1 always showed higher ε values than the enrichment culture when grown on the same carbon source due to culture-specific properties. Higher ε values were obtained when the enrichment culture was grown on PHC components than on organic acids. No relationship between ε values and cell-specific sulfate reduction rate existed when all data were combined. When comparing the magnitude of ε values determined in this laboratory study with ε values measured at contaminated and uncontaminated field sites, it becomes evident that a multitude of factors influences ε values at field sites and complicates their interpretation. The results of this study help us assess some of the general parameters that govern the magnitude of ε in sulfate-reducing environments.

Chemical composition of snowfall in the high Arctic: 1990–1994

From 1990 to 1994 at Alert, Nunavut, Canada, weekly snow samples were collected under low wind conditions to avoid contamination by blowing snow. They were analysed for major ions, Br −, and the organic ions methylsulphonate, formate, acetate and propionate. In the Arctic, where annual precipitation is low and blowing snow is common, these observations are unique. On an equivalent weight basis, acids and sea salt in snowfall are mixed approximately equally from December to January but from March to May acids dominate. The acidity of snowfall increases progressively throughout the winter to a May peak of ∼16 μeq l −1. SO 4 2−, Br −, and the organic acids acetate, and propionate peak in snowfall after polar sunrise indicate the influence of enhanced photochemical reactions. The greater enrichment of halides relative to sea salt Na + in snow compared to aerosols indicates that gaseous uptake by snowflakes is important in the removal of these substances from the atmosphere and their deposition on to the Earth's surface. There is a marked difference between the seasonal variation of enrichment of Cl − and Br − in snow. The latter show a marked increase after polar sunrise while the former does not. These results provide valuable baseline information on the ionic content of fresh snowfall to be used in understanding the results of snowpack chemistry and post-depositional process studies conducted in the high Arctic.

Effects of the removal of extracellular Ca 2+ on [Ca 2+] i responses to FCCP and acetate in carotid body glomus cells of adult rabbits

The effects of the removal of extracellular Ca 2+ on the responses of cytosolic concentrations of Ca 2+ ([Ca 2+] i) to acidic stimuli, a protonophore carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) and an organic acid acetate, were examined in clusters of cultured carotid body glomus cells of adult rabbits using fura-2 microfluorometry. Application of FCCP (1 μM) induced an increase in [Ca 2+] i (mean±S.E.M., 108±14%). After withdrawal of the protonophore the increased [Ca 2+] i returned slowly to a resting level. The [Ca 2+] i response was attenuated by an inorganic Ca 2+ channel antagonist Ni 2+ (2 mM) by 81±4%, and by an L-type voltage-gated Ca 2+ channel antagonist D600 (10 μM) by 53±13%. The removal of extracellular Ca 2+ eliminated the [Ca 2+] i response in 71% of the tested cells ( n=17), and depressed it by 68±6% in the rest. Recovery following stimulation with FCCP in the absence of Ca 2+ reversibly produced a rapid and large rise in [Ca 2+] i, referred to as a [Ca 2+] i rise after Ca 2+-free/FCCP. The magnitude of a [Ca 2+] i rise after Ca 2+-free/FCCP (285±28%, P<0.05) was larger than that of an increase in [Ca 2+] i induced by FCCP in the presence of Ca 2+ and had a correlation with the intensity of the suppression of the [Ca 2+] i response by Ca 2+ removal. A [Ca 2+] i rise after Ca 2+-free/FCCP was inhibited mostly by D600. Similarly, recovery following exposure to acetate in the absence of Ca 2+ caused a rise in [Ca 2+] i, referred to as a [Ca 2+] i rise after Ca 2+-free/acetate which was sensitive to D600. The magnitude of the [Ca 2+] i rise was larger than that of a change in [Ca 2+] i caused by acetate in the presence of Ca 2+. These results suggest that FCCP-induced increase in [Ca 2+] i was, in most cells, due to Ca 2+ influx via L-type voltage-gated Ca 2+ channels and, in some cells, due to both Ca 2+ influx and Ca 2+ release from internal Ca 2+ pool. The removal of extracellular Ca 2+ might modify [Ca 2+] i responses to acidic stimuli, causing [Ca 2+] i rises after Ca 2+-free/acidic stimuli which involve mostly L-type Ca 2+ channels.

A Structure-Activity Study with Aryl Acylamidases

We examined the relationship between chemical structure and biodegradability of acylanilide herbicides by using a set of model compounds. Four bacterial isolates (one gram-negative and three gram-positive) that grew on acetanilide were used. These soil isolates cleaved the amide bond of acetanilide via an aryl acylamidase reaction, producing aniline and the organic acid acetate. A series of acetanilide analogs with alkyl substitutions on the nitrogen atom or the aromatic ring were tested for their ability to induce aryl acylamidase activity and act as substrates for the enzyme. The substrate range, in general, was limited to those analogs not disubstituted in the ortho position of the benzene ring or which did not contain an alkyl group on the nitrogen atom. These same N-substituted compounds did not induce enzyme activity either, whereas the ortho-substituted compounds could in some cases.