Showing papers on "Methyl isobutyl ketone published in 1997"

Additives To Lower and Stabilize the Viscosity of Pyrolysis Oils during Storage

Abstract: The initial development of additives to stabilize the viscosity of biocrude during long-term storage has produced dramatic results. The additives investigated were ethyl acetate, methyl isobutyl ketone and methanol, acetone, methanol, acetone and methanol, and ethanol. These additives represent three chemical families, which all demonstrated the ability to drastically reduce the aging rate of biocrude, as defined by the increase in viscosity with time. Accelerated aging tests were run at 90 °C to screen the additives. The additives not only lowered the initial viscosity at 40 °C by half but also reduced the aging rate of a hot gas filtered pyrolysis oil made from hybrid poplar (NREL run 175) by factors of 1−18 compared to the original pure oil. With the best additive, methanol, at a 10 wt % level in the pyrolysis oil, the modified biocrude was still a single-phase liquid and still met the ASTM No. 4 diesel fuel specification for viscosity even after 96 h exposure to 90 °C. Based on the aging rate at 90 °C...

Transient behavior of biofilters: Start-up, carbon balances, and interactions between pollutants

Abstract: The work describes the aerobic biodegradation of volatile organic compound (VOC) mixtures from effluent air streams in laboratory-scale compost based biofilters. A rapid start-up of the system (3–5 d) was observed and 82% of the carbon in the influent pollutant (methyl ethyl ketone) was recovered as carbon dioxide in the exhaust air after this period. Biofilter performance and carbon dioxide production were also investigated during and after 0.5–1-h step inputs of 2–10 g m−3 of hexane, acetone, 1-propanol, and/or methyl isobutyl ketone (MIBK) during steady methyl ethyl ketone (MEK) treatment. Carbon dioxide patterns suggest that pulsed pollutants were first sorbed onto the packing material and subsequently degraded within 2–5 h. Hexane was not sorbed, and thus not degraded to a significant extent. Little effect was observed of the step inputs on the overall MEK removal process, mainly because the reactors were operated well below MEK breakthrough loading. However, the analysis of MEK profiles within the b...

Selective oxidation of 5-hydroxymethylfurfural to 2,5-furan-dicarboxaldehyde in the presence of titania supported vanadia catalysts

Abstract: Oxidation of 5-hydroxymethylfurfural to 2,5-furan-dicarboxaldehyde was performed in a batch reactor at 363 K in the presence of supported V 2 O 5 /TiO 2 catalysts with different vanadium loadings, and in toluene and methyl isobutyl ketone as the solvents. An air pressure of 1.6 MPa allowed the fast in situ regeneration of the catalyst and the complete transformation of the starting reactant. It appears that a multilayered V 2 O 5 /TiO 2 catalyst with a structure close to that of bulk V 2 O 5 is preferred since involving more V=O species responsible for the oxidation of alcohols. In addition, a higher turnover frequency is obtained in the presence of methyl isobutyl ketone as the solvent. This is particularly suitable for a further development of the reaction on a pilot scale as far as 5-hydroxymethylfurfural is extracted with that solvent in the preceding chemical step and thus may be directly used in the oxidation step.

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).

Extraction of Phenol Using Trialkylphosphine Oxides (Cyanex 923) in Kerosene

Abstract: A group of extractants based on phosphine oxides have been reported as an alternative to conventional polar solvents for phenol liquid-liquid extraction. Among phosphoryl extractants, Cyanex 923 (a mixture of four trialkylphosphine oxides, alkyl = normal, C6, C8) has proved to combine high extraction efficiency and low water solubility (1, 2), obviating the necessity of removing the solvent from the aqueous raffinate, a need asso- ciated with the use of methyl isobutyl ketone and isopropyl ether, the solvents most widely employed for this application (3, 4).

Amine extraction of hydroxycarboxylic acids. 3. Effect of modifiers on citric acid extraction

Abstract: The extraction equilibrium in the systems aqueous solution of a hydroxycarboxylic acid−solution of trialkylamine in an organic diluent can be largely modified by the nature of the diluent. Binary diluents composed of a neutral paraffinic solvent and an active modifier can be used to adjust the desired equilibrium behavior of a particular system. In the present work the equilibria in the systems aqueous solutions of citric acid−solutions of trialkylamine in binary diluents have been measured. Chloroform or methyl isobutyl ketone has been used as modifiers and n-heptane as neutral diluent. Besides these two data systems earlier data for the system with 1-octanol as modifier are also considered. Different mathematical models for correlating these data are proposed comprising specific effects of formation of various acid−amine complexes and nonspecific effects of interactions among the components of the organic phase. The optimum parameter values of the individual models are presented, and the goodness of fit...

Perstraction of Phenolic Compounds from Aqueous Solution Using a Nonporous Membrane

Abstract: An exploratory study of nondispersive extraction of various phenolic solutes using a nonporous membrane has been carried out. Sorption and permeation data for these solutes have been obtained using a silicone rubber membrane. The effects of hydrodynamic factors, concentration of phenols, and temperature on the trans-membrane flux are discussed. A film model is used to determine the intrinsic mass transfer characteristics of the membrane. Comparison of sorption of phenolic solutes from the membrane into the organic solvent indicates that methyl isobutyl ketone is a better solvent than butyl acetate.

Determination of iron in alkaline salts by ICP-AES using 1-(2-Thiazolylazo)-p-cresol (TAC) for preconcentration and separation

Abstract: The present paper describes the use of 1-(2-thiazolylazo)-p-cresol (TAC) for separation, preconcentration and determination of iron traces (ng g-1) in alkaline salts by the ICP-AES technique. The proposed method is based on the liquid-liquid extraction of the complex formed between iron(III) and 1-(2-thiazolylazo)-p-cresol (TAC). Parameters such as: TAC amount, pH effect, influence of the organic solvent on the extraction, back extraction and mineralization of the organic phase were studied. The results show that the iron(III)-TAC complex, formed in the pH range from 4.0 to 10.0, can be quantitatively extracted from saline solutions (up to 30% NaCl) using isoamyl alcohol, carbon tetrachloride, chloroform or methyl isobutyl ketone as extracting solvent. The solution for the iron determination can be obtained by a back extraction using 1 mol/L hydrochloric acid or 1 mol/L nitric acid solutions or also by mineralization of the organic phase, which was accomplished by evaporation of the organic solvent and digestion of the residue with concentrated nitric acid. The procedure was used for iron determination in several alkaline salt samples. The standard addition technique was applied and the recoveries obtained revealed that the proposed procedure has a good accuracy.

Determination of Nickel in Alkaline Salts by Inductively Coupled Plasma Atomic Emission Spectroscopy Using 1-(2-Thiazolylazo)-p-Cresol for Preconcentration and Separation

Abstract: The present paper describes the use of 1-(2-thiazolylazo)-p-cresol (TAC) for separation, preconcentration and determination of nickel (ng g−1) in alkaline salts using Inductively Coupled Plasma Atomic Emission Spectroscopy technique (ICP-AES). The method proposed is based on the liquid-liquid extraction of the complex formed between nickel(II) cation and 1-(2-thiazolylazo)-p-cresol (TAC). Parameters such as: TAC concentration, effect of pH, influence of the organic solvent on the extraction, back extraction and mineralisation of the organic phase were studied. The results demonstrated that nickel in the form of nickel(II)-TAC complex, in the pH range of 5.0 to 12.0, can be quantitatively extracted from saline solutions (up to 30% NaCl) using the following solvents: isoamyl alcohol, carbon tetrachloride, chloroform, xylene, hexane, butyl acetate or methyl isobutyl ketone. The solution for the nickel determination can be obtained by a back extraction using 5 ml of a 1M hydrochloric acid solution or...

Inductively coupled plasma mass spectrometry for the sequential determination of trace metals in sea water after electrothermal vaporization of their dithiocarbamate complexes in methyl isobutyl ketone

Abstract: A sensitive method has been developed for the sequential determination of V, Mn, Fe, Co, Ni, Cu, Zn, Mo and Sb in sea water using inductively coupled plasma mass spectrometry (ICP-MS) after electrothermal vaporization of their dithiocarbamate complexes in methyl isobutyl ketone (MIBK). After complexion with sodium diethyldithiocarbamate (NaDDTC), all trace analyte elements were simultaneously separated from sea water matrix and concentrated 20 fold in a single extract of MIBK, followed by introduction of 10 μL of the extract into argon plasma using a pyrolytic graphite rod electrothermal vaporizer (ETV). Sensitivity enhancement due to chemical modification using a mixed modifier of Pd(NO3)2-Mg(NO3)2 was observed for all the elements. The limits of detection ranged from 2 ng/L for Co to 329 ng/L for V. For replicate determinations of the elements in sea water, the repeatability was within 10% (as a coefficient variation), except for V (12.8%). The recovery test performed on a sea water sample resulted in a range value from 87% for Sb to 119% for V. The method has been successfully applied to sea water samples collected from the surface to the depth of 5000 m at a sampling station in the northwest Pacific Ocean.

Effects of unsteady state conditions on the biooxidation of methyl ethyl and methyl isobutyl ketone in continuous flow liquid phase cultures

Abstract: The effects of changing operating conditions on the biooxidation of methyl ethyl and/or methyl isobutyl ketone in continuous flow enrichment culture are examined. Particular emphasis is placed on responses to step changes in feed stream concentrations and to substrate pulses injected directly into the culture supernatant. In general, the enrichment culture was better able to handle transients involving methyl isobutyl ketone, the preferred carbon substrate. However, the highly complex response patterns observed clearly indicated major gaps in knowledge concerning the physiology of methyl ketone-oxidizing bacteria. In spite of the two carbon substrates investigated being major environmental pollutants, their removal in waste biotreatment processes is remarkably little understood.

Amine curatives for flexibilized epoxies

Abstract: Reductive alkylation of branched, short chain diamines, such as 2-methyl-1,5-pentanediamine, with certain aldehydes or ketones of moderate molecular weight, such as benzaldehyde or methyl isobutyl ketone, produces novel tri- and difunctional amines which are useful in curing epoxy resins to compositions having improved flexibility and enhanced resistance to moisture and chemicals. Particularly favorable results are achieved when this curative is combined in the epoxy formulation with low molecular weight acrylic copolymers added as flexibilizers. Further improvements are available by including in the recipe monofunctional epoxy or acrylic reactive diluents.

One step synthesis of mibk (methyl isobutyl ketone) from acetone over CaO-supported Ni catalyst

Abstract: One step synthesis of MIBK from acetone over Ni/CaO catalysts was studied. 10 wt% Ni/CaO catalysts were prepared by conventional impregnation method (catalyst I), and liquid phase oxidation method using NaOCl as an oxidant (catalyst L). Catalyst L showed much higher activity than catalyst I because of recovered CaO pore structure and high BET surface area. Catalyst C, prepared by coprecipitation method, showed 60% of MIBK selectivity with a fairly high overall acetone conversion. Catalysts L and C had two CO2 desorption states (α, Β). Incorporated Ni enabled support precursor [Ca(CO)3] to decompose easily into CaO andCO2even at low temperature and generated weakCO2desorption state (α) which was from active state.

Organopolysiloxane resin composition

Abstract: PROBLEM TO BE SOLVED: To provide a silanolated organopolysiloxane resin compsn. which does not undergo condensation even at room temp., is excellent in storage stability, and hardly exhibits the change in quality with time. SOLUTION: This compsn. contains 100 pts.wt. siloxane resin represented by the average compsn. formula: R 1 n Si(OR 2 ) p (OH) q O (4-n-p-q)/2 and 40-2,000 pts.wt. at least one org. solvent selected from among org. solvents having permittivities (at 10-35°C) of 4-16 (pref. tert. butanol, tert. amyl alcohol, methyl isobutyl ketone, or tetrahydrofuran). In the formula, R 1 is H or a 1-8C org. group; R 2 is 1-6C alkyl; and 0≤n≤1.8, 0≤p≤1.0, and 2≤q≤3 provided 0.8≤(n+p+q)<4. COPYRIGHT: (C)1998,JPO

Sequential determination of trace metals in sea water by inductively coupled plasma mass spectrometry after electrothermal vaporization of their dithiocarmabamate complexes in methyl isobutyl ketone

Abstract: A sensitive method for sequential determination of V, Mn, Fe, Co, Ni, Cu, Zn, Mo and Sb in sea water using an inductively coupled plasma mass spectrometry (ICP-MS) after electrothermal vaporization of their dithiocarbamate complexes in methyl isobutyl ketone (MIBK) has been investigated. All analyte elements were simultaneously concentrated 20 fold in a single extract and introduced into the plasma using a graphite rod electrothermal vaporizer (ETV). A sensitivity enhancement due to a chemical modification using a mixed modifier of palladium nitrate and magnesium nitrate was observed for all analyte elements. The limits of detection of the method ranged from 2 ng l-1 for Co to 329 ng l-1 for V. For the replicate determinations of the analyte elements in a sea water sample, the repeatability was within 10% (as a coefficient variation), except for V (12.8%). The recovery test performed on a sea water sample resulted in values ranging from 87% for Sb to 119% for V. With the exception of Mo, the application of this method for the determination of the analyte elements in sea water samples collected from the surface to the depth of 5000 m at the sampling station of 34°12.08′N, 141°57.50′E (Oct. 12, 1994) in the northwest Pacific Ocean resulted in vertical distributions and concentration ranges which were in a good agreement with those reported in literatures.

Rubber composition obtained by recycling scrap material

Abstract: A rubber composition obtained by recycling scrap material and adapted for use as raw material for manufacturing products for building, automobile accessory, and footwear industries possibly as a replacement for wood, zinc sheet, fiber cement, plastic and any other rigid or semirigid material The composition includes from about 66% to about 77% of particles of ground tires having a size between about 18 and about 30 microns, from about 15% to about 22% of particles of ground plastic material having a size between about 18 and about 30 microns, and from about 8% to about 12% of a solution of acid with toluene or methyl isobutyl ketone The acid may be lactic acid, phosphoric acid or formic acid The percentage of acid in the solution by volume is from about 12% to about 50% and the percentages of toluene or methyl isobutyl ketone in the solution by volume is from about 50% to about 88%

Process for the extraction of hydroperoxides

Abstract: A process for extraction of hydroperoxides wherein 1,3-di-(2-hydroperoxy-2-propyl)benzene and 3-(2-hydroxy-2-propyl)-1-(2-hydroperoxy-2-propyl)benzene are extracted from a raw solution comprising 1,3-di-(2-hydroperoxy-2-propyl)benzene, 3-(2-hydroxy-2-propyl)-1-(2-hydroperoxy-2-propyl)benzene and an aqueous sodium hydroxide solution, said process using methyl isobutyl ketone containing not more than 10 ppm by weight of a phenol or phenols as a solvent for extraction.

Method to de-couple methyl isobutyl ketone and diisobutyl ketone co-produced from acetone and/or isopropyl alcohol

Abstract: A method for the catalytic manufacture of MIBK and DIBK from DMK and/or IPA (optionally in the presence of water) while obtaining improved control over the ratio of DIBK to MIBK in the product stream, comprising reacting, in the presence of an aldol condensation catalyst, a reactant mixture comprising DMK and/or IPA and an effective amount of an additional reactant selected from the group consisting of mesityl oxide (MSO) and methyl isobutyl carbinol (MIBC) and mixtures thereof. Reaction temperature may also be changed to affect the product ratio obtained. The preferred catalyst is copper-based. An overall excess of hydrogen is desired, and this may be achieved by introducing or recycling hydrogen, and/or by balancing exothermic and endothermic reactions. By this invention, the product ratio of DIBK to MIBK is altered such that, as DMK and/or IPA conversion is increased, a lesser amount of DIBK than normal is produced, resulting in improved ability to control the product ratio of these materials.

Dissolution rates for thin films of miscible polymer blends

Abstract: The dissolution rates of thin polymer films were measured and compared. Mixtures of various ratios of poly( methyl methacrylate), PMMA, and poly(p-hydroxy-styrene), PPHS, were dissolved in methyl isobutyl ketone, MIBK. The polymer solutions were then spun into thin films on silicon wafers and dried. The coated wafers were immersed in an MIBK bath and the rate of dissolution was observed using laser interferometry. The results show that pure PPHS films have dissolution rates 1000 times greater than films of pure PMMA at comparable molecular weights. However, for films containing both PPHS and PMMA, a minimum dissolution rate occurs for a mixture with about 20% (by weight) PPHS.

Chemical separation procedure for the nuclide analysis of a tantalum target irradiated for 500 days with 800 MeV protons

Abstract: A rapid radiochemical separation procedure has been developed for the determination of long-lived and stable nuclides produced by spallation and activation in a tantalum target irradiated for 500 days with 800 MeV protons. In this procedure the matrix element tantalum and simultaneously the182Ta activity, built-up by activation of the matrix with themalized spallation neutrons is removed from many elements. About 50 mg of the sample is dissolved in a mixture of concentrated nitric and hydrofluoric acid. After dilution tantalum is extracted with a solution of 0.2M tetrahexylammonium bromide in methyl isobutyl ketone (MIBK). The residual amount of tantalum and the remaining182Ta activity are 0.0003% and the recoveries of 27 investigated elements are in the range of 96.0–99.9%. A further 22 elements are quantitatively separated according to their chemical behavior. In the final aqueous fraction the separated long-lived and stable nuclides of 49 elements can be measured with high sensitivity by γ-ray spectrometry and mass spectrometry (ICP-MS).

Differential Pulse Polarographic Determination of Uranium in Bituminous Coal

Abstract: A liquid-liquid extraction and determination of uranyl ion in coal ash have been investigated. Synergistic effects were observed using a combination of thenoyltrifluoracetone, tributyl phosphate, and methyl isobutyl ketone. After the separation of interfering ions by precipitation with a hot ethanolic solution of thioacetamide, the determination of uranyl ion was performed by differential pulse polarography using a solution of 1.0 M TRIS-HCl as supporting electrolyte. The average uranium content in bituminous coal was in agreement with the spectrophotometric method using 4-(2-pyridylazo)resorcinol.

A Contribution on the Determination of Bromazepam by Its Ferrous Complex Formation.

Abstract: The determination of bromazepam by spectrophotometry and atomic absorption on the basis of the extraction in methyl isobutyl ketone of the ionic-pair bromazepam-Fe(II) cationic chelate and perchlorate is discussed. Differential spectrophotometry must be used for measuring low levels of the diazepine. Both techniques were applied for determining bromazepam in pharmaceuticals.