Methyl Isobutyl Research Articles

Sulfonium-Functionalized Polystyrene-Based Nonchemically Amplified Resists Enabling Sub-13 nm Nanolithography.

Nonchemically amplified resists based on triphenyl sulfonium triflate-modified polystyrene (PSTS) were prepared by a facile method of modification of polystyrene with sulfonium groups. The uploading of the sulfonium group can be well-controlled by changing the feed ratio of raw materials, resulting in PSTS0.5 and PSTS0.7 resists with sulfonium ratios of 50 and 70%, respectively. The optimum developer (methyl isobutyl ketone/ethanol = 1:7) is obtained by analyzing contrast curves of electron beam lithography (EBL). PSTS0.7 exhibits a better resolution (18 nm half-pitch (HP)) than the PSTS0.5 resist (20 nm HP) at the same developing conditions for EBL. This novel resist platform was further evaluated by extreme ultraviolet lithography, and patterning performance down to 13 nm HP at a dose of 186 mJ cm-2 with a line edge roughness of 2.8 nm was achieved. Our detailed study of the reaction and patterning mechanism suggests that the decomposition of the polar triflate and triphenyl sulfonium groups into nonpolar sulfide or polystyrene plays an important role in the solubility switch.

Measurement and Thermodynamic Modeling of Liquid–Liquid Equilibrium Data for Ternary Systems (Water + Formaldehyde + Methyl Isobutyl Ketone/Cyclohexanone) at Different Temperatures

Measurement and Thermodynamic Modeling of Liquid–Liquid Equilibrium Data for Ternary Systems (Water + Formaldehyde + Methyl Isobutyl Ketone/Cyclohexanone) at Different Temperatures

Continuous purification of phosphoric acid in a microchannel

Solvent extraction is an economically efficient method widely used in the purification of wet phosphoric acid. In this study, microchannel was applied to promote mixing and purification of phosphoric acid during continuous production. For this aim, liquid-liquid extraction was conducted to purify phosphoric acid via methyl isobutyl ketone/tri-butyl phosphate mixtures. Additionally, the Box-Behnken experimental design method was used to survey the liquid-liquid extraction process. The effect of various operational parameters such as solvent concentration (45–65 %wt.), temperature (18-28˚C) and organic/aqueous phase ratio (2:1–6:1) at a constant flow rate of 70 ml/l was examined. Experimental results indicated that the microchannel at the residence time of 6.85 min could promote the extraction percentage of and sulfate removal more than 98% and 60%, respectively, compared to the batch extractor.

Continuous Industrial-Scale Centrifugal Partition Chromatography with Automatic Solvent System Handling: Concept and Instrumentation

Centrifugal partition chromatography (CPC) is an emerging separation technology in pharmaceutical and natural product purifications, reaching recently industrial-scale solutions. Because both the stationary and mobile phases are liquids in CPC, the solvent consumption of such separation processes is considered significant. Thus, automation is highly required in the preparation and recycling of the solvent mixtures for economical (i.e., continuous) CPC operation. Here, we report a feasible solution for this industrial issue, including the concept, algorithm, and instrumentation of solvent system handling. For majority of ternary solvent systems used in CPC separations, the linear correlation between the density and composition of the phases was recognized and utilized during the continuous solvent recycling. Hence, an efficient density-based composition adjustment algorithm was established in a mixer-settler unit using Coriolis flow meters for precise density monitoring of the upper and lower phases of the biphasic liquid system (BLS). In addition, a complete cascade consisting of a buffer, waste, a recycler (evaporator), and mixer-settler units was designed around the industrial-scale CPC device. The proof of concept was demonstrated by sequential industrial-scale CPC separations of a binary model mixture in the n-hexane/methanol/water (5/4/1, v/v/v) solvent system, followed by the purification of a crude steroid active pharmaceutical ingredient performed in the methyl isobutyl ketone/acetone/water (2/2/1, v/v/v) solvent system. The reproducibility of chromatographic performance and the productivity of the mixer-settler and evaporator units were satisfactory, enabling a robust and continuous operation of the developed separation process.

Characterization of tar generated from the mixture of municipal solid waste and coal pyrolysis at 800 °C

Nowadays, comprehensive perception of the tar characteristics generated from municipal solid waste (MSW) and coal to guide pyrolysis or gasification gas yield upgrading and cleaning has attracted massive research attention. In this study, MSW and coal samples were chosen as principal components. The mixture of these products was pyrolyzed in a horizontal tube furnace at 800 °C with a heating rate of 20 °C/min. The tar derived from the pyrolysis of this mixture was further studied. Gas chromatography–mass spectrometry (GC–MS)coupled with a trace GC and a nuclear magnetic resonance (NMR) spectrometer was applied to investigate the tar composition and characterization along with their molecular chemical structures. 1H and 13C NMR spectra indicated that the functional groups of the tar derived from the mixture of MSW and coal were dominant at the resonances of 0.9–1.8 ppm, 1.5–2.6 ppm and 3.8–4.1 ppm for 1H, 10–40 ppm and 60–80 ppm for13C. The results from GC–MS showed that the tar derived from the mixture of MSW and coal contained about 20 major chemical compounds such as benzene, methyl isobutyl, toluene, xylene, phenol, cresol, naphthalene and others.

Synthesis of Branched Octahydro-Indene with Methyl Benzaldehyde and Methyl Isobutyl Ketone

Branched octahydro-indenes were first synthesized with methyl isobutyl ketone (MIBK) and methyl benzaldehyde, which can be obtained from lignocellulose. Initially, C14 oxygenates were prepared by t...

Effect of gas superficial velocity (Jg) and frother/collector (MIBC/X-343) reagent dosage on froth horizontal displacement and galena drainage

This paper attends the study of froth behaviour for the design of future launder, crowder and scraper configurations. The effect of gas superficial velocity (Jg) and Methyl Isobutyl Carbinol/Sodium Isopropyl Xanthate (MIBC/X-343) reagent dosage on froth horizontal displacement, bubble size of the froth surface, froth velocity, froth carrying capacity, grade and particle size of the concentrate obtained, was studied. A novel experimental apparatus was constructed to promote the free transport of froth in its horizontal displacement using three output sections each 200mm long to extend the overflow lip to 200, 400 and 600mm from the flotation cell. The aim of this new experimental apparatus was to magnify the phenomena that occur in the froths. Attending this consideration, the present apparatus cannot be compared with industrial flotation cells but was particularly useful for describing phenomena on froth transport. The results show that the froth horizontal displacement was promoted at high levels of Jg, while high levels of frother/collector reagent dosage promote high froth carrying capacity and longer media half-life inhibiting bubble collapse as an effect of the mineral layer and the hydrated layer on the bubble. An adequate selection of both study variables generates a well loaded and fluid froth, which can survive for longer distances toward the overflow lip. On the other hand, the galena concentration increased or decreased across the horizontal displacement as a function of both Jg and frother/collector reagent dosage.

Root Scent Composition in Valeriana officinalis and Valeriana edulis ssp. procera Analyzed by HS-SPME-GC-MS a.

The headspace solid-phase micro extraction (HS-SPME) procedure coupled with gas chromatography-mass spectrometry (GC-MS) was used to determine profiling volatile components from the roots of Valeriana officinalis and Valeriana edulis ssp. procera. In the two species were identified more than 30 compounds finding terpenoids and aliphatic esters as principal metabolites. The major components in V. officinalis were camphene (31.13%) and bornyl acetate (11.15%), whereas isobutyl isovalerate (46.28%) and methyl isovalerate (13.42%) were the major components in V. edulis ssp. procera.

VAPOUR-LIQUID EQUILIBRIUM IN SYSTEMS WITH ISOBUTYL ACETATE, ACETIC ACID AND METHYL ETHYL KETONE

The experimental temperature dependence of the vapour pressures of isobutyl acetate, acetic acid and methyl ethyl ketone were determined, and isobaric vapour-liquid equilibrium data of binary systems of methyl ethyl ketone + isobutyl acetate and methyl ethyl ketone + acetic acid were obtained. The experimental data were processed using the Antoine and Riedel equations and the NRTL and Wilson local composition equations, respectively. Comparison of the experimental and calculated data confirmed the adequacy of the vapour-liquid equilibrium mathematical simulation.

Autocatalytic Production of 5-Hydroxymethylfurfural from Fructose-Based Carbohydrates in a Biphasic System and Its Purification

An efficient autocatalytic process for the production of 5-hydroxymethylfurfural (HMF) from fructose-based carbohydrates has been investigated without the addition of any external catalysts in a methyl isobutyl ketone/water biphasic system, leading to elevated HMF yield through continuous extraction of HMF from an aqueous solution. The results show that both the reaction temperature and time have significant effects on fructose conversion and HMF yield; 96.8% of fructose can be converted into 73.6% of HMF with a small amount of levulinic acid and formic acid formed at a point of compromise between the reaction temperature and time (160 °C for 2 h). In addition, this autocatalytic system is suitable for other fructose-based feedstocks, such as sucrose and inulin, to achieve acceptable HMF yield. Moreover, a simple and efficient purification strategy for as-prepared HMF, viz., the NaOH neutralization method, has also been tested, achieving more than 99% of HMF recovery with more than 98% of purity correspon...

Removal of organic solvent from cathodic electrophoretic emulsion paint by vacuum steam stripping

The production of environmental friendly emulsion paint is of great significance. Vacuum steam stripping of methyl isobutyl ketone (MIBK) and methyl ethyl ketone (MEK) from cathodic electrophoretic emulsion was studied. The effects of mass ratio of vapor to feed (V/F), vacuum degree and feed temperature on removal rate of MIBK and MEK, emulsion size and solid volume fraction of the emulsion were investigated, and the removal of MIBK and MEK from cathodic electrophoretic emulsion by vacuum desorption was also studied. The results show that removal rates of both MIBK and MEK increase with the increase of V/F, vacuum degree and feed temperature. Removal rates of MIBK and MEK are 98.3% and 93.6%, respectively, at the operating condition V/F of 0.7, feed temperature of 27 °C and vacuum degree of 90 kPa. The emulsion size of cathodic electrophoretic emulsion increases slightly with feed temperature when temperature is below 42 °C, and increases rapidly with feed temperature when temperature is above 42 °C. Solid volume fraction increases by 10% as vacuum degree increases from 0 to 90 kPa at V/F of 0.7 and feed temperature of 27 °C. Compared with vacuum desorption, vacuum steam stripping can get a higher removal rate of MIBK and MEK under the same feed flow, vacuum degree and feed temperature.

A new irreversible enzyme-aided esterification method in organic solvents

A new irreversible esterification method for carboxylic acids catalyzed by a lipase from Candida antarctica (Novozyme 435) in organic solvents has been developed. The water produced during the process is chemically destroyed by a corresponding ester of acetoacetate, which acts as a sacrificial substrate in this reaction. The flavour esters isobutyl acetate, methyl butyrate, ethyl butyrate and benzyl butyrate were synthesized either in small scale (0.05 mol) or large scale (1 mol). The yields range from 82 to 92% within 24 h at 52 degrees C. Optimal molar ratios of reactants were 1:1:1 (carboxylic acid:alcohol:acetoacetate).

Further evidence for the development of photic-zone euxinic conditions during Mesozoic oceanic anoxic events

Periods in Earth history characterized by extensive organic carbon deposition, so-called oceanic anoxic events (OAEs), are the subject of considerable scrutiny. Insight into the extent of anoxic conditions in the water column has been provided by the reported occurrence of derivatives of isorenieratene, a carotenoid found only in green sulphur bacteria and thus indicative of photic-zone euxinia (i.e. a water column containing free H 2 S), in North Atlantic deep-sea sediments deposited during the Cenomanian–Turonian boundary OAE2 (Bonarelli Event). In this study, we have used the distributions of chlorophyll and bacteriochlorophyll degradation products, maleimides (1- H -pyrrole-2,5-diones) and high molecular weight porphyrins, to examine further the Cenomanian–Turonian boundary OAE2 as well as other OAEs of the early Toarcian (Posidonienschiefer Event) and early Aptian (Selli Event). In particular, methyl isobutyl (Me, i -Bu) maleimide, on structural grounds, appears to be diagnostic of green sulphur bacteria. This compound occurs in five of seven examined marls that record the early Toarcian OAE (Marche–Umbria, Italy), further expanding the geographical range of Toarcian sediments where evidence for photic-zone euxinic conditions has been found. Me, i -Bu maleimide occurs in three of six black shales spanning the Livello Selli (Marche–Umbria, Italy), the type locality for the Aptian OAE1a, providing the first evidence for photic-zone euxinic conditions during this event. With respect to the Cenomanian–Turonian OAE, maleimide evidence for photic-zone euxinic conditions was found in all the North Atlantic sites investigated, including those characterized by relatively organic-lean sediments, several Tethyan sites and one site off western Australia. These data indicate that euxinic conditions were common in the water column during Mesozoic oceanic anoxic events.

2H-NMR investigation after a polymerisation-induced phase separation process*

Polymer-dispersed liquid crystals (PDLC) are composite materials consisting of micron-sized droplets of liquid crystal dispersed in a polymer matrix. The easiest method to obtain a PDLC film is the polymerisation-induced phase separation process (PIPS). The liquid crystal is mixed with a monomer of low molecular weight and polymerisation is induced by heat or UV light. The increasing molecular weight of the polymer causes the phase separation of liquid crystal from the polymer matrix as micron-sized droplets. In this work, we have studied the structural changes induced in the polymer matrix of a PDLC after the PIPS process by deuterium nuclear magnetic resonance. Two different selectively deuterated monomers have been synthesized and investigated: isobutyl methacrylate (IBMA-d2) and methyl methacrylate (MMA-d3). The main results were the disappearance of the characteristic two-site hop in poly-IBMA, due to liquid crystal molecules, and the lack of unreacted MMA molecules in the liquid crystal droplets. In this last case, we found that it is possible to confine temporarily the unreacted MMA molecules within liquid crystal droplets.

Diastereoselective Alkylation of Tricyclic Lactim Ethers

Alkylations of tricyclic 1-methoxy-3,6,11,11a-tetrahydro-4H-pyrazino[1,2-b]isoquinolin-4-one (5) were studied under various conditions. The highest conversions were obtained when LDA or LHMDS were used for the deprotonation step. The diastereoselectivity turned out to be highly dependent on the electrophile. While methyl iodide, isobutyl bromide, 4-methylpent-3-enyl bromide, and isopropyl bromide yielded mixtures of trans and cis diastereomers 10 and 11, respectively, allyl bromide, 3-methylbut-2-enyl bromide, and benzyl bromide yielded the trans-product 10 with high diastereoselectivity. X-ray crystal structures of 5 and its synthetic precursor 9 were determined. The alkylated lactim ethers 10a,c,g and 11a−c were converted into the corresponding dioxopiperazines 12a,c,g and 13a−c in high yields. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

Methyl isobutyl ketone and methyl ethyl ketone in urine as biological markers of occupational exposure to these solvents at low levels.

To examine whether unmetabolized methyl isobutyl ketone in urine is a useful marker of low-level occupational exposure to this ketone solvent, as is the case for methyl ethyl ketone. The study was conducted in the second half of a working week. In total, 27 furniture-making workers (19 men and eight women) and 11 non-exposed controls (six men and five women) volunteered to participate in the study. Time-weighted average (TWA; 8-h) concentration of vapors of several solvents in air, including methyl isobutyl ketone (MIBK-A) and methyl ethyl ketone (MEK-A) was monitored by diffusive sampling. Urine samples collected at the end of the shift were subjected to head-space gas chromatography (GC) analysis for the unmetabolized solvents (i.e., MIBK-U and MEK-U). The relationship between the concentration of the solvent vapor and the corresponding solvent level in urine was examined by simple as well as multiple regression analysis. The exposures to MIBK and MEK were well below the current occupational exposure limit levels, but the maximum levels of exposure to toluene and ethylbenzene were around the corresponding exposure limit. The correlation of the TWA concentration of the solvent in air with the concentration of the corresponding solvent in the end-of-shift urine sample was significant both for MIBK and for MEK, and the correlation coefficient was larger for MIBK than for MEK. The slope in the exposure-excretion regression line was almost twice as steep for MEK than for MIBK, possibly due to the difference in water solubility. Approximately 0.12% of MIBK absorbed in the lungs will be excreted into urine, whereas the yield for MEK was somewhat higher (0.19%). MIBK in urine is a good marker of exposure to MIBK, as in the case of MEK in urine for MEK exposure.

Reaction of glycidyl phenyl ether with imines: A model study of latent hardeners of epoxy resins in the presence of water

AbstractThe hydrolyses of several imines and their reactions with glycidyl phenyl ether were examined under highly humid conditions as a model study for the development of water‐initiated hardeners for epoxy resins. Diethyl ketone‐based imines were hydrolyzed more efficiently than methyl isobutyl ketone‐based imines. The reactions of glycidyl phenyl ether with the imines depended on their hydrolysis rates and the basicity of the amines generated from them. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 971–975, 2002

Diethyl ketone‐based imine as efficient latent hardener for epoxy resin

AbstractSeveral imines were synthesized and evaluated as water‐initiated hardener for epoxy resin. Imines with a lower electron density on the C=N carbon showed a faster hydrolysis rate. Diethyl ketone‐based imines were the most efficiently hydrolyzed among the imines examined, and the adhesive properties of epoxy resin with diimines used as the hardeners were evaluated. A novel diethyl ketone‐based diimine, N,N′‐di(1‐ethylpropylidene)‐m‐xylylenediamine (10), served as an efficient latent hardener of epoxy resin. Epikote 828 containing 10, filler, and dryer increased the adhesive strength faster than Epikote 828 containing filler and dryer with methyl isobutyl ketone‐based imine. The mixed system of epoxy resin and 10 showed good storage stability at room temperature. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1744–1749, 2002

The adsorption of methyl isobutyl ketone and methyl isobutyl carbinol onto graphite studied as a function of evaporation temperature

Atomic force microscopy has been used to study structures found on the surface of graphite following the liquid-phase adsorption of two organic solvents, methyl isobutyl ketone and methyl isobutyl carbinol. The graphite surface was examined following the evaporation of each solvent at temperatures ranging from 25°C to 300°C. The areas of decoration consisted primarily of isolated features whose profile was dependent on the solvent deposited. For the ketone, a linear relationship was found between the height and diameter of the isolated features. In addition to isolated features, low-temperature evaporation of the solvents produced graphite terraces decorated with aggregate morphologies showing spatial organisation. At higher evaporation temperatures, only isolated features were observed at the graphite steps. The differences in the results are attributed to the distinctive chemical functionality of the two solvents.

New method of phosphorus determination with improved pretreatment of occluded iron phosphate fraction in soils

In the sequential fractionation of phosphorus (P), a modified approach in the oxidation process of the occluded fraction of P (in iron oxides in soils) using redox titration in nitric acid (HNO3) medium is presented. Also a new spectrophotometric method to determine that P fraction as the phosphomolybdate complex using a mixture of isobutyl acetate and methyl isobutyl ketone to extract the formed complex into the organic phase. Radioactive tracer (32P) and sequential extraction is used to state the yield of extraction of the phosphomolybdate complex. Accuracy, precision, detection limit, and the linearity of the present method are 1.04%, 0.0322 μg mL‐1, 0.0038 ug mL‐1, and 0–15 ug mL‐1, respectively. The results correlate significantly with the results of the standard method of Petersen and Corey (1966), and the procedure saves time (50 min) and chemicals.