Methyl Isobutyl Ketone Research Articles

Dielectric, refractometric, and volumetric studies on mixing behavior of two structurally related ketones and glycols systems

The dielectric, refractometric, and volumetric properties were systematically investigated for eight binary systems containing two structurally related ketones (methyl isobutyl ketone and mesityl oxide) and four glycols over the entire composition range at 298.15 and 101 kPa. The selected glycols were (1,3-butylene glycol, pentamethylene glycol, diethylene glycol, and triethylene glycol). The experimental data were analyzed using different approaches in terms of intermolecular interactions between the constituent molecules through excess parameters of different physical quantities. The excess parameters confirm the formation of multimer structure during the mixing process. In addition, the refractive index deviations were calculated in terms of volume fraction. Based on the Iglesias-Reis approach, the influence of the interactions in excess Helmholtz energy and excess permittivity from total interactions follow the same order 1,3BG > DE > PG > TEG for their mixtures with the ketones. All the excess Kirkwood correlation factors (giE) are negative but very small for the mixtures. Thus, the Kirkwood correlation factors for binary mixtures (g12) are not very far from the ideal behavior, and therefore, the dipoles preferentially oriented parallel interrupted for some extent by the mixing process. The Redlich–Kister type polynomial equation was used to fit the experimental excess parameters.

АТОМНО-АБСОРБЦИОННЫЙ МЕТОД КОНТРОЛЯ ЭЛЕМЕНТОВ ИЗНОСА МОТОРНЫХ МАСЕЛ В РАЗЛИЧНЫХ УСЛОВИЯХ ПРИМЕНЕНИЯ

The content of wear metals in engine oils allow you to control over time both the change in the properties of oils and the serviceability of engine components. An analysis of the pattern of changes in the elemental composition of the oil makes it possible to evaluate the effectiveness of the use of flushing and break-in motor oils, to control the process of cleaning used oils and changes in the properties of oils in agricultural machinery engines during the off-season storage period. Determination of wear elements (iron, aluminium, copper and chromium) was carried out on an MGA-915M atomic absorption spectrometer manufactured by Lumex LLC Atompribor. The running-in efficiency of the D-240 engine was controlled by changing the concentration of wear elements. The composition of the break-in oil included: 1% of the mass. urea + 0.5% wt. graphene concentrate + 1% wt. oleic acid - the rest is refined motor oil. A pyro-coated graphite furnace with a Lvov platform was used as an atomizer. A working preservation oil containing an additional 6% polymerized rapeseed oil and 6% gun grease was prepared on the basis of purified M-10DM motor oil. Solutions of engine oil samples were prepared by diluting them with methyl isobutyl ketone, chemically pure grade. Flushing oil obtained by refining used oil has been found to effectively remove wear elements from the engine. The content of iron decreased by 2.5 times, aluminum by 1.5 times, copper by 5 times, and chromium by 3 times. It has been determined that cleaning the oil with ammonium hydroxide and carbamide flushes the engine more efficiently compared to cleaning with a mixture of isopropanol (3%) and mono-ethanolamine (3%). Researches of motor oils in friction units of combines were carried out in a comparative mode - in motor oil before installation of combines for storage and after storage for six months. It is concluded that it is expedient to replace oils before storage after summarizing the results obtained by determining the elements of wear products in motor oils that worked in the engines of combine harvesters, their precipitation during storage (idle time).

Modelling, optimal solvent screening and separation of 5-hydroxymethylfurfural or furfural from catalytic conversion reactor stream in downstream purification process

An overall process evaluation-based solvent selection for the biphasic catalytic conversion of the sugars into bio-based 5-hydroxymethylfurfural (5-HMF), furfural (FURF) and for the downstream separation and purification sequence was carried out, which represents an important step in industrial operating procedure. In the chemical process screening for 5-HMF extraction, the various dissolving fluids of different molecular polarity were used, parallel batch experiments were performed, and a few were identified as potential substance solutions for either, 5-HMF or FURF. Criteria were based on the ability to form two liquid phases within an aqueous thermodynamic system, to have fast transport kinetics, and simultaneously extract the 5-HMF and/or FURF with a high partitioning coefficient. The feasibility of the constituents’ pure mixture in terms of waste material efficiency, its resource recovery and the purity of both product species were also a part of the criteria. The best solute-partitioning alternatives found, besides an organic benchmark methyl isobutyl ketone (MIBK), were benzyl alcohol, tetrahydrofuran (THF) with an addition of sodium salt and homologues, resulting from the determined efficacy analysis, modelling and optimisation of the continuous purification methodology by means of partition, distillation and thermal heat recuperation. This allows for designing a diluted carbohydrate stream integrated bio refining in the wake of pulping.

Springtime reactive volatile organic compounds (VOCs) and impacts on ozone in urban areas of Yunnan-Guizhou plateau, China: A PTR-TOF-MS study

Field observations of reactive volatile organic compounds (VOCs) were carried out in Kunming, the largest city on the Yunnan-Guizhou Plateau. Proton transfer reaction-time-of-flight mass spectrometry (PTR-TOF-MS) was used to conduct a 40-day online observation. VOCs were characterized, including concentrations, diurnal variations, ozone generation potential, and source apportionment. The results show 18 main observed active VOCs (acetaldehyde, 2-acrolein, acetone, methyl ethyl ketone (MEK), methyl vinyl ketone (MVK), methacrolein (MACR), methyl isobutyl ketone (MIK), 2-pentanone, ethyl acetate, isoprene, α-pinene, benzene, toluene, styrene, C8 aromatic hydrocarbons, C9 aromatic hydrocarbons, 1,3-dichlorobenzene, naphthalene and acetonitrile) with a total concentration of (10.97 ± 5.21) ppb. Eight OVOCs have a total concentration of (7.49 ± 3.10) ppb; two biogenic VOCs (BVOCs) have a total concentration of (1.32 ± 0.79) ppb, and six aromatic hydrocarbons have a total concentration of (1.50 ± 1.14) ppb. The ozone formation potential of isoprene, acetaldehyde and 2-acrolein make up the top three species. The main sources of three OVOC species (acetaldehyde, acetone, and MEK) have local biological sources and primary anthropogenic sources, indicating that the pollution in this area is significantly affected by regional transport. This study can improve our scientific understanding of the composition and sources of VOCs on the Yunnan-Guizhou Plateau and fundamental ozone control in the region.

Reactive Extraction of Betaine from Sugarbeet Processing Byproducts.

Betaine from natural sources is still preferred over its synthetic analogue in secondary industries. It is currently obtained by expensive separation means, which is one of the main reasons for its high cost. In this study, reactive extraction of betaine from sugarbeet industry byproducts, that is, molasses and vinasse, was investigated. Dinonylnaphthalenedisulfonic acid (DNNDSA) was used as the extraction agent, and the initial concentration of betaine in the aqueous solutions of byproducts was adjusted to 0.1 M. Although maximum efficiencies were obtained at unadjusted pH values (pH 6, 5, and 6 for aqueous betaine, molasses, and vinasse solutions, respectively), the effect of aqueous pH on betaine extraction was negligible in the range of 2-12. The possible reaction mechanisms between betaine and DNNDSA under acidic, neutral, and basic conditions were discussed. Increasing the extractant concentration significantly increased (especially in the range of 0.1-0.4 M) the yields, and temperature positively (but slightly) affected betaine extraction. The highest extraction efficiencies (∼71.5, 71, and 67.5% in a single step for aqueous betaine, vinasse, and molasses solutions, respectively) were obtained with toluene as an organic phase solvent, and it was followed by dimethyl phthalate, 1-octanol, or methyl isobutyl ketone, indicating that the efficiency increased with decreasing polarity. Recoveries from pure betaine solutions were higher (especially at higher pH values and [DNNDSA] < 0.5 M) than those from vinasse and molasses solutions, indicating the adverse influence of byproduct constituents; however, the lower yields were not due to sucrose. Stripping was affected by the type of organic phase solvent, and a significant amount (66-91% in single step) of betaine in the organic phase was transferred to the second aqueous phase using NaOH as the stripping agent. Reactive extraction has a great potential for use in betaine recovery due to its high efficiency, simplicity, low energy demand, and cost.

Development of a Moisture Pretreatment Device for the Accurate Quantitation of Water-Soluble Volatile Organic Compounds in Air

In air pollutant monitoring using sensors, moisture can adversely affect the analytical accuracy of volatile organic compounds (VOCs). Therefore, a new moisture pretreatment device (KPASS–Odor) for analyzing VOCs in the air was developed, based on frost and created by a desublimation process inside a cold tube. The performance of KPASS–Odor was compared with conventional devices (i.e., a NafionTM dryer and a cooler) through the measurements of low water-soluble VOCs (i.e., benzene, toluene, ethyl benzene, p-xylene, and styrene) and relatively high ones (i.e., methyl-ethyl ketone, methyl isobutyl ketone, butyl acetate, and isobutyl alcohol) using gas chromatography (GC) and sensor methods. Regarding the GC method, the recovery rates for KPASS–Odor and the cooler were &gt;95% and &gt;80%, respectively, at a flow rate of 500 mL/min for all compounds. For the NafionTM dryer, the recovery rates differed between low and high water-soluble compounds, which exhibited the rates ≥88% and ≤86%, respectively. In terms of the sensor method, the VOC recovery rates of KPASS–Odor and the NafionTM dryer were found to be &gt;90% and &lt;50%, respectively. Therefore, KPASS–Odor was determined to be the most suitable moisture pretreatment device for highly soluble VOCs of concern in this study.

Solid-liquid phase equilibrium and thermodynamic properties analysis of paliperidone palmitate in 21 kinds of mono-solvents

Solid-liquid equilibrium solubility paliperidone palmitate (PP) in 21 kinds of mono-solvents, including ethanol, n-propanol, i-propanol, n-butanol, i-butanol, s-butanol, n-pentanol, i-pentanol, 2-butanone, methyl isobutyl ketone, cyclohexanone, ethyl formate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, amyl acetate, N,N-dimethylformamide (DMF), tetrahydrofuran (THF), toluene, and 1,4‑dioxane were determined by a gravimetric method at a various temperature. The solubility of PP increases with the increase of temperature. In alcoholic solvents, the solubility order is: n-pentanol > i-pentanol > i-butanol > s-butanol > n-butanol > n-propanol > i-propanol > ethanol. In easter solvents, the solubility of PP ranking as: ethyl formate > amyl acetate > butyl acetate > propyl acetate > ethyl acetate > isopropyl acetate. For ketone solvent, the solubility order is: cyclohexanone > 2-butanone > methyl isobutyl ketone. In other solvents, the solubility order is: THF > toluene > 1,4‑dioxane > DMF. The maximum solubility of PP is 0.1922 mol·mol−1 (toluene, 353.15 K), and the minimum solubility is 0.0003788 mol·mol−1 (ethanol, 318.15 K). Four thermodynamic models, i.e., the modified Apelblat model, the Yaws model, the NRTL model and the Wilson model were selected to correlate the solubility data in this paper. NRTL model fits best among all the models with RAD no larger 4.84 × 10−2 (n-propanol) and RMSD value less than 12.55 × 10−4 (1,4-dioxane). Furthermore, dissolution thermodynamic properties of PP were evaluated based on the Wilson model. The dissolution process of PP is demonstrated to be spontaneous in the chosen organic solvents.

Investigations into the Extraction of Copper (II) using Methyl Isobutyl ketone solvent

AbstractThis work concerns the study of the extraction of copper (II) in the perchlorate medium by Bis‐2‐ethylhexyl phosphoric acid (D2EHPA) in methyl isobutyl ketone (MIBK) at 25 °C at different ionic strength (1, 1/6, 1/10 mol kg−1). The stoichiometry of the reaction of extracted complexations was determined by the slope method. The organometallic complexes extracted in the organic phase are of the type CuL2 in methyl isobutyl ketone has unit ionic strength. The organometallic complexes extracted in the organic phase are of the type CuL2ClO4(H2O) or CuL2ClO4 (MIBK)x in methyl isobutyl ketone has different ionic strength Efficiency of the extraction of copper (II) depends on the ionic strength of the aqueous medium. Hence when the ionic strength of the aqueous perchlorate medium increases the extraction of copper (II) increases.

5-Hydroxymethylfurfural synthesis from fructose over deep eutectic solvents in batch reactors and continuous flow microreactors

In this work, a deep eutectic solvent (DES) composed of choline chloride (ChCl) and ethylene glycol (EG) was prepared and applied for the conversion of fructose to 5-hydroxymethylfurfural (HMF), catalyzed by HCl in both laboratory batch reactors and continuous flow microreactors. The effects of reaction temperature, batch time, catalyst loading and molar ratio of ChCl to EG on the fructose conversion and HMF yield were first investigated in the monophasic batch system of ChCl/EG DES. To inhibit HMF-involved side reactions (e.g., its polymerization to humins), methyl isobutyl ketone (MIBK) was used as the extraction agent to form a biphasic system with DES in batch reactors. As a result, the maximum HMF yield could be enhanced at an MIBK to DES volume ratio of 3:1, e.g., increased from 48% in the monophasic DES (with a molar ratio ChCl to EG at 1:3) to 63% in the biphasic system at 80°C and 5 mol% of HCl loading. Based on the optimized results in batch reactors, biphasic experiments were conducted in capillary microreactors under slug flow operation, where a maximum HMF yield of ca. 61% could be obtained in 13 min, which is similar to that in batch under otherwise the same conditions. The slight mass transfer limitation in microreactors was confirmed by performing experiments with microreactors of varying length, and comparing the characteristic mass transfer time and reaction time, indicating further room for improvement.Highlights• The efficient fructose conversion to HMF in deep eutectic solvents was achieved in batch reactors and microreactors.• An HMF yield over 60% could be obtained at a fructose conversion above 90% in both reactors at 80°C within 14 min.• The HMF yield was enhanced from 48% in the monophasic ChCl/EG system to 63% in the DES-MBIK biphasic system in batch.• A slight mass transfer limitation was found in the biphasic slug flow microreactor.Graphical

Sulphonic Acid‐Functionalized Polymeric Ionic Liquids Catalyzed Conversion of Carbohydrates into Levulinic Acid in One‐Pot Reaction

AbstractSulphonic acid‐functionalized polymeric ionic liquids (PILs) were synthesized and applied into catalytic conversion of cellulose into levulinic acid (LA). The structure, thermal stability, and Hammett acidity function (H0) of PILs were characterized and all were more thermostable than those of small‐molecular ionic liquids (IL). At the optimum reaction conditions, the LA yield was maximized to 79.4 % by catalyst [Pim]CH3SO3. More importantly, catalyst [Pim]CH3SO3 performed well in other biomass conversion, such as cellobiose, starch and rice husk. The product LA can be easily extracted by methyl isobutyl ketone from the reaction mixture. The PILs with high catalytic activity were easily recycled with an LA yield up to 68.9 % even after five cycles. These sufficient PILs will offer new approaches for transforming biomass to platform chemicals.

Aldol condensation of furfural and methyl isobutyl ketone over Zr-MOF-808/silica hybrid catalysts

Mesoporous silica-supported Zr-MOF-808 catalysts have been synthesised and tested in the aldol condensation of (biomass-derived) furfural and methyl isobutyl ketone to bio-jet fuel precursors. Growth of Zr-MOF-808 nanocrystals over silica scaffolds results in well-dispersed Zr species which confer strong Lewis acidity as determined by FTIR of chemisorbed pyridine. Hybrid Zr-MOF-808/silica materials exhibit higher condensation activity than the unsupported crystalline Zr-MOF-808 (which is also prone to rapid deactivation). Textural properties of the silica support strongly influence the catalytic performance, with a high surface area and sufficiently large mesopore desirable. In the screening, the optimum Zr-MOF-808/MCM-41 catalyst delivered 68 % furfural conversion and 90 % selectivity to the C11 aldol adduct, 1-(furan-2-yl)-5-methylhex-1-en-3-one, at 130 °C and a furfural:Zr mass ratio of 150:1. Although more stable than the pure Zr-MOF-808, the Zr-MOF-808/MCM-41 also suffered significant deactivation over successive condensation reactions due to strongly adsorbed organic residues, however this was largely ameliorated by decreasing the furfural:Zr ratio to 75:1, which also led to an outstanding catalytic performance (100 % furfural conversion and adduct selectivity), likely because of the suppression of furfural polymerization.

Biological Buffer Effect on Liquid–Liquid Equilibria of Systems Containing n-Butanol + Methyl Isobutyl Ketone + Water

Biofuel, that is, n-butanol, production from plant-based biomass represents a renewable energy resource that can be a substitute for fossil fuel. Thus, it is important to study the separation of n-butanol from its aqueous solution to obtain a high-purity product. Liquid–liquid extraction is a beneficial process in alcohol production to recover alcohol from the aqueous medium. Liquid–liquid equilibrium (LLE) data are needed for rational design and optimal separation operation, such as biological separation and extraction processes. The objective of this study is to determine LLE data for quaternary systems of n-butanol, methyl isobutyl ketone (MIBK), water, and a biological buffer at 303.15 K and atmospheric pressure (P = 0.1 MPa). The effect of biological buffer addition into aqueous solution was also studied. Three different biological buffers, 4-(2-hydroxyethyl)-1-piperazine propanesulfonic acid (EPPS), 4-morpholinepropanesulfonic acid (MOPS), and 4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid (HEPES), were applied in this study for the comparison. The separation factor and distribution coefficient were evaluated in this study to interpret the extraction performance of n-butanol. According to the experimental results, the extraction performance was in the order of HEPES > EPPS > MOPS, describing the strength of buffering-out as well. Furthermore, it was found that the aid of a biological buffer in the LLE systems consisting of n-butanol, MIBK, and water resulted in better extraction performance than that of the LLE systems in the absence of a biological buffer. The reliability of the experimental LLE tie-line data was satisfactorily ascertained by the Hand correlation. The non-random two-liquid and universal quasi-chemical thermodynamics models correlated well the experimental LLE tie-line data with the root mean square deviation of less than 1%. The binary interaction parameters of both models were also obtained in this study.

Sustainable recovery of phenolic antioxidants from real olive vegetation water with natural hydrophobic eutectic solvents and terpenoids

Olive oil production leads to the generation of olive mill wastewater (OMWW). Due to the presence of phenolic compounds, they are difficult to process, but they represent a source of high-added value chemicals since they have antioxidant and therapeutic properties. This work has studied the extraction of phenolic compounds from a type of OMWW, olive vegetation water, which presents these compounds in a more diluted dosage than in other studied to date, to revalue this waste stream. A real olive vegetation water from a Spanish olive oil producer was used, and liquid-liquid extraction was applied. Terpenoids and terpene-based hydrophobic eutectic solvents were systematically used to extract phenolic compounds following the concentrations of tyrosol, catechol, caffeic acid, and total phenolic content. By molecular simulation with the COSMO-RS method, 4 terpenoids, and 2 eutectic solvents were selected and compared with 2 conventional solvents. The Solvent/Feed ratio in the extraction of phenolic compounds was studied, showing that the solvents with the highest extraction results were geraniol, eucalyptol, and eutectic solvent menthol + camphor, which outperformed conventional solvents methyl isobutyl ketone and diisopropyl ether. Menthol + camphor gave total phenol extraction yields of 88.73% at a Solvent/Feed ratio in volume of 0.50, surpassing all solvents tested. A solvent reuse and regeneration process was applied by back-extraction of the 4 solvents: FTIR results showed the stability of the solvents while maintaining yields in the solvent reuse process. The phenolic compounds could be concentrated in the alkaline phase to factors up to 49.3 to the initial concentration in olive vegetation water. The alkaline phases were neutralized to obtain a precipitate with a caffeic acid content of up to 26 % wt%, and a tyrosol-rich supernatant with a concentration of up to 6.54 g/L. This work proposes a process using natural solvents to extract phenolic compounds from olive vegetation water.

Quantitative detection of organic mercury in whole blood using derivatization and gas chromatographynegative chemical ionization-mass spectrometry

The Minamata disease, first identified in Japan in the 1950s, is caused by severe methylmercury (MeHg) poisoning. To prevent the development of this disease, routine evaluation of MeHg levels in blood samples is crucial. The purpose of this research was to explore the use of derivatization and capillary gas chromatography-negative chemical ionization-mass spectrometry (GC-NCI-MS) for the quantitative detection of both organic and inorganic mercury in blood samples. Alkyl mercury in standard solutions was extracted as halide salts in toluene with hydrohalic acid. Fat contents in whole blood samples were removed by methyl isobutyl ketone and hexane using a cysteine/alkaline solution and then organic mercury was extracted as a bromide complex using toluene and cupper chloride solution. The linearity of the response ratio vs. concentration curves (R2) was 0.987 for methylmercury bromide and 0.990 for ethylmercury bromide. over the calibration range of 0.02 ng/mL to 20 ng/mL. The recovery of MeHg and ethylmercury (EtHg) was 67.1% and 49.3%, respectively. The concentrations of MeHg in whole blood samples determined using GC with an electron capture detector agreed with those determined using GC-NCI-MS, with a correlation coefficient of 0.923. The mean concentration of MeHg in a certified reference material (NMIJ CRM 7402-a) determined using GC-NCI-MS was 0.64 μg/g, comparable with the certified value of 0.58 μg/g. Our study demonstrates a simple and low-cost approach for analyzing mercury in biological samples, although further optimization is required given the relatively low recovery and the concern about the toxicity of methyl isobutyl ketone.

An efficient chemoenzymatic cascade strategy for transforming biomass into furfurylamine with lobster shell-based chemocatalyst and mutated ω-transaminase biocatalyst in methyl isobutyl ketone-water

To date, an efficient process for manufacturing valuable furan compounds from available renewable resources has gained great attention via a chemoenzymatic route. In this study, a sulfonated tin-loaded heterogeneous catalyst CLUST-Sn-LS using lobster shell as biobased carrier was prepared to convert corncob (75.0 g/L) into furfural (122.5 mM) at 170 °C for 30 min in methyl isobutyl ketone (MIBK)–H2O biphasic system (2:1, v/v). To improve furfurylamine yield, a novel recombinant E. coli TFTS harboring robust mutant Aspergillus terreus ω-transaminase [hydrophilic threonine (T) at position 130 was site-directed mutated to hydrophobic phenylalanine (F)] was constructed to transform 300–500 mM furfural into furfurylamine (90.1–93.6 % yield) at 30 °C and pH 7.5 in MIBK-H2O. Corncob was converted to furfurylamine in MIBK-H2O with a high productivity of 0.461 g furfurylamine/(g xylan). This constructed chemoenzymatic method coupling bio-based chemocatalyst CLUST-Sn-LS and mutant ω-transaminase biocatalyst in a biphasic system could efficiently convert lignocellulose into furfurylamine.

Extraction and Depolymerization of Lignin from Pine Sawdust and Pistachio Shells

Lignocellulosic biomass is a renewable resource that contains three major constituents: cellulose, hemicellulose, and lignin. Lignin is a potential source of aromatic phenols. The extraction and subsequent depolymerization of lignin was studied using pine sawdust and pistachio shells. Lignin extraction used 70:30 methyl isobutyl ketone:ethanol followed by 0.1M H2SO4. The extraction yield of lignin was 15.78 ± 3.38% from pistachio shells and 18.86 ± 1.52% from pine sawdust. The extracted lignin was characterized using Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and 1H-NMR spectroscopy. The extracted lignin was depolymerized using subcritical water and a Ni-Graphene catalyst at 240 °C for 10 min. The depolymerization products were identified as phenolic monomers, such as phenol, guaiacol, vanillin, syringol, guaiacylpropane, syringaldehyde, coniferaldehyde, synapyl alcohol, and synapyl aldehyde, using GC-MS.

Microwave-assisted choline chloride/1,2-propanediol/methyl isobutyl ketone biphasic system for one-pot fractionation and valorization of Eucalyptus biomass

The developing of pretreatment method to break the biomass barrier of lignocellulosic is a challenging task for achieve high value utilization. A fast microwave-assisted choline chloride/1,2-propanediol/methyl isobutyl ketone biphasic system was constructed for pretreating Eucalyptus to the production of furfural and cellulose-rich residues and the extraction of lignin. Results showed that the combination of AlCl3·6H2O and HCl had the best catalytic ability for furfural production among the examined catalysts. Under the optimal conditions (140 °C, 15 min, 0.075 M AlCl3·6H2O, 0.05 M HCl), the furfural yield of 55.4 %, the glucose yield of 90.3 % and the delignification rate of 92.4 % could be achieved. Moreover, the extracted lignin samples with a low polydispersity (1.55–1.73) and molecular weight (1380–2040 g/mol) are promising to act as precursor for the value-add products processing. These findings demonstrated an ultrafast pretreatment process with excellent results in biomass fractionation and comprehensive utilization of biomass components.

Process optimization for enzymatic production of a valuable biomass-based ester from levulinic acid.

The enzymatic production of isoamyl levulinate via esterification of isoamyl alcohol (IA) and levulinic acid (LA), a biomass-based platform chemical with attractive properties, in a solvent system has been performed in this study. For such a purpose, a low-cost liquid lipase (Eversa® Transform 2.0) immobilized by physical adsorption via hydrophobic interactions (mechanism of interfacial activation) on mesoporous poly(styrenene-divinylbenzene) (PSty-DVB) beads was used as heterogeneous biocatalyst. It was prepared at low ionic strength (5mmol.L-1 buffer sodium acetate pH 5.0) and 25℃ using an initial protein loading of 40mg.g-1 of support. Maximum protein loading of 31.2 ± 2.8mg.g-1 of support and an immobilization yield of 83% was achieved. The influence of relevant factors (biocatalyst concentration and reaction temperature) on ester production was investigated using a central composite rotatable design (CCRD). Maximum acid conversion percentage of 65% was achieved after 12h of reaction at 40°C, 20% of mass of heterogeneous biocatalyst per mass of reaction mixture (20% m.m-1), and LA:IA molar ratio of 1:1.5 in a methyl isobutyl ketone (MIBK) medium. The biocatalyst retained around of 30% of its initial activity after five consecutive esterification batches under optimal experimental conditions. The proposed experimental procedure can be considered as an acceptable green process (EcoScale score of 66.5), in addition to the fact that a new strategy is proposed to sustainably produce a valuable industrial ester (isoamyl levulinate) from biomass-based materials using an immobilized and low-cost commercial lipase as catalyst.

Rapid determination of chemical concentration and odor concentration of paint-emitted pollutants using an electronic nose

Volatile pollutants emitted from building materials are an important source of indoor air pollution. The development of rapid determination methods for the chemical concentration and odor concentration of these volatile pollutants is of great importance. The present work investigated the difference in the concentration of pollutants emitted by various paint samples, from which key pollutants (methyl isobutyl ketone, ethylbenzene, and xylene) were screened based on their concentration and odor contribution. Then, an electronic nose (E-nose) device was developed to determine the chemical concentrations of key pollutants and the odor concentration of gas emitted by paint samples. A total of 135 gas samples emitted by the selected paint were measured by the developed E-nose, by gas chromatography–mass spectrometry and by olfactory testing. The obtained sensor response values and chemical and odor concentrations were divided randomly and used for training and testing of the E-nose pattern recognition algorithm. The trained pattern recognition algorithm was able to accurately output the target values, with average relative errors of 10.0%, 10.4%, 7.6%, and 10.0% (test set, n = 13) for the methyl isobutyl ketone, ethylbenzene, and xylene chemical concentrations and the odor concentration, respectively. In addition, the cross-sensitive nature of the E-nose showed a unique advantage in determining odor concentration compared to the odor conversion model. The excellent performance of the developed E-nose demonstrates that this work provides a practical solution for the rapid determination of the chemical concentration and odor concentration of pollutants emitted by building materials.

The effectiveness of kitchen ventilation for organic gaseous compound control in Chinese residential buildings

The health hazards of cooking oil fume (COF) exposure underscore the importance of effectively controlling air pollution in kitchens, especially during cooking. The effectiveness of ventilation for gaseous pollutant control deserves more attention due to its toxicity, odor and strong diffusivity. In this study, field measurements of 23 carbonyl compounds before and during cooking in 120 Chinese residential kitchens were carried out to obtain carbonyls pollution status during cooking and to explore the effectiveness of kitchen ventilation for gaseous compounds. Carbonyls were actively sampled by dinitrophenylhydrazone adsorption tubes and analyzed by high performance liquid chromatography (HPLC) to accurately determine the concentrations. Overall, the mean concentration of total carbonyls was 496.2 μg/m3 during cooking with the range hood turned on, among which formaldehyde (153.6 μg/m3), acetaldehyde (121.3 μg/m3), and acrolein & methyl isobutyl ketone (92.8 μg/m3) had the highest mass concentration proportion (a total of 74%). Even with the range hood on, the carbonyls concentration could increase by approximately 200 μg/m3 under “Door Close, Window Close” conditions, indicating insufficient ventilation for diluting the pollutant. If Ccooking/Cnon-cooking = 1 was considered an acceptable gaseous pollutant control criterion, only 39%, 43%, 56%, and 65% of the kitchen with ventilation rates of <15 h−1, 15–25 h−1, 25–35 h−1, and >35 h−1 met the criteria, respectively. The effective exhaust air flow rate of the 25th–75th percentiles was distributed in the range of 4.3–8.9 m3/min, and the actual mean air flow rate was only 44% of the rated air flow rate stated by range hood manufacturers. Therefore, the effective ventilation rate was still not enough for gaseous pollutants in real residential kitchens, and the organized air supplement in the kitchen is crucial to control cooking pollution.