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The liquid–liquid equilibrium (LLE) of the mesityl oxide + diethoxymethane + water was determined at 303.15, 313.15 and 323.15 K under 101.325 kPa, which was consistent with the Treybal's type II ternary phase behavior. The distribution coefficients (D) and selectivity coefficients (S) were used to evaluate the extraction ability of mesityl oxide to extract diethoxymethane from water. The experimental data were correlated with the NRTL and UNIQUAC thermodynamic models, and the RMSD values are both less than 0.47%, indicating that the two models can well correlate the experimental data. [ABSTRACT FROM AUTHOR]

The electrochemistry of dimethoxybenzene isomers and 2,2'-dihydroxy-4,4'-dimethoxybenzophenone is discussed in this paper concerning their electrooxidation in acetonitrile, allyl alcohol and mesityl oxide. The voltammograms of 1,2- and 1,4-isomers were reproducible in each solvent, only the 1,3-isomer fouled the platinum macroelectrode. In case of 2,2'-dihydroxy-4,4'-dimethoxybenzophenone a low electronically conducting film was formed in all of the investigated solvents. In mesityl oxide, the growing film showed significant adsorption capability towards the substrate molecules. Microelectrode studies shed light to interesting phenomena due to the increased mass transport to the electrode surface, in case of dimethoxybenzenes leading to more conducting polymers. The specially formed film from 2,2'- dihydroxy-4,4'-dimethoxybenzophenone demonstrated its adsorption capability towards selected compounds. [ABSTRACT FROM AUTHOR]

The results of a study of tandem reactions - aldol-crotonic condensation and hydrogenation by the mechanism of hydride transfer in acetone-isopropanol mixtures on a МgSnО3 catalyst at 300–400°C and 12.0 MРa are presented. In these conditions the mixture of reactants (acetone and isopropanol) and reaction products is in supercritical state. The temperature dependences of the reactants conversion and the selectivity for condensation and hydrogenation products are considered. It has been established that the hydrogenation of acetone aldol-crotonic condensation products proceeds by the addition of hydrogen from isopropanol molecule to C=O-bonds of isomeric mesityl and phorone oxides and is accompanied by dehydration of alcohols and isomerization of double C=C-bonds. The optimal conditions for the formation of the carbonyl group hydrogenation products are 350°C and the ratio acetone : isopropanol = 7 : 3. At the acetone to isopropanol ratio 1 : 1, methylpentadienes dominate in the products of mesityl oxide conversion. The hydrogenation reaction also proceeds with the participation of isophorones, the condensation products of three acetone molecules. [ABSTRACT FROM AUTHOR]

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This study explores the characteristics of electrodeposition of the three hydroxybenzaldehyde isomers and selected hydroxybenzoic acids (4-hydroxybenzoic acid, salicylic acid, 3,5-dihydroxybenzoic acid) from mesityl oxide solvent. Similar to recent advances of this solvent, used by electrochemical studies, the carbon–carbon double bond had significant influence on the formation of polymers from the outlined molecules. In case of most substrates the peak currents increased to a steady-state but electropolymerization of some substrates caused significant deactivation. Scanning electron microscopic and complementary voltammetric studies facilitated that the electrochemically formed polymers are present on the electrode surface in stackings. In viewpoint of analysis of 2-phenylphenol, the modifying deposit formed from 4-hydroxybenzaldehyde was the best with 5 µM detection limit obtained with differential pulse voltammetry. Furthermore, a new procedure was chosen for the involvement of a cavitand derivative into the organic layers with the purpose to improve the layer selectivity (subsequent electrochemical polymerization in an other solution). Further studies showed that in this way the sensitivities of as-modified electrodes were a little worse than without this step, thus indicating that application of this step is disadvantageous. Recovery studies of 2-phenylphenol were carried out on lemon rind without any treatment, and it was compared with the case when the outer yellow layer was removed by rasping. The inner tissues showed very high adsorption affinity towards 2-phenylphenol. [ABSTRACT FROM AUTHOR]

The electrooxidation of 1,2,4-benzenetriol was studied in different non-aqueous solvents. The results showed that the studied substance can be oxidized in several ways on the electrode surface due to the favourable positions of hydroxyl groups (similarly to hydroquinone, resorcinol and catechol). In most cases one anodic peak appeared involving all possible electrode processes. The concentration dependence of voltammetric peak currents using platinum macroelectrode showed nonlinearity attributable to the 1,3-oxidation similarly to resorcinol leading to partial deactivation. Appearance of more peaks indicated the weak deactivation at higher concentrations in acetonitrile and nitrobenzene. At higher concentration the microelectrode became deactivated as in the successive scans the currents declined continuously reinforcing the existence of resorcinol pathway. [ABSTRACT FROM AUTHOR]

The electropolymerization of three phenylphenol isomers was studied in methyl isobutyl ketone and mesityl oxide, and the remarkable differences highlighted the importance of the carbon–carbon double bond in mesityl oxide. In the case of each substrate, a brownish deposit formed during the electrooxidation. The obvious difference between the polymers formed from the two solvents was recognized via voltammetric signal enhancement of 4-methoxyphenol and 4-chlorophenol, and it was only observed in the case of mesityl oxide. The experiments highlighted that incorporation of a cavitand with biphenyl groups on the upper rim of the polymers of phenylphenols improved the results to a small extent. The cavitand was, itself, electroactive without any fouling effect. As 2-phenylphenol is by far the cheapest of the three isomers, a cavitand was incorporated into its polymer, which was exploited to solve analytical problems while mesityl oxide was used as solvent. Useful quantifications were achieved in organic solvents; however, it failed under aqueous conditions due to the high hydrophobicity of the deposit. Application of differential pulse voltammetry for 4-methoxyphenol and 4-chlorophenol gave detection limits of 9.28 and 50.8 μM in acetonitrile, respectively. This procedure resulted in the immobilization of cavitand derivatives onto the electrode's surface, and the layer formed offered selective sensing of phenols by electrochemical methods. [ABSTRACT FROM AUTHOR]

Using the results of an earlier study of the physicochemical properties of the reaction system of the process of producing mesityl oxide, an analysis of the statics of the combined variant of the organization of this process was carried out. It is shown that of practical interest are the modes of the process corresponding to the first specified separation. In this case, the limiting stationary states, characterized by the maximum acetone conversion, selectivity, and the yield of the target product — mesityl oxide, are distinguished. The possibility of practical implementation of the limiting stationary state of the reactive distillation process for producing mesityl oxide, which provides almost complete conversion of acetone with a yield of mesityl oxide approaching 100%, has been proved. The limit stationary state corresponds to the reaction-distillation process with the selection of a single product stream. For the mode of carrying out the combined process that corresponds to the selected limiting stationary state, a schematic flow chart for the production of the target product has been proposed. By means of computational research, it has been established that the most rational option for organizing a reaction hub is to use a single apparatus in it — the reaction-distillation column. In the Aspen Plus® software package, a process model was constructed that corresponded to the proposed technological scheme and through a computational experiment, its structural and parametric optimization was carried out. As a result, the static parameters of the technological system were established, as well as the characteristics of the apparatuses, allowing to obtain the required quality product in the reactiondistillation column. output, approaching 100%. It has been shown that when modeling a chemicaltechnological system, it is necessary to use different sets of parameters of the basic equation used to describe phase equilibrium. Thus, for calculating reactive distillation and distillation columns, the liquid – vapor phase equilibrium parameters for the mesityl oxide–water system should be used, and when calculating the Florentine vessel for this mixture, it is necessary to use the parameters corresponding to the liquid – liquid equilibrium. The use of a single set of parameters of the basic equation leads to significant errors and inadequate description of the process of producing mesityl oxide by condensation of acetone.

Acetone is generated upon mesityl oxide (MO) adsorption on TiO2 at 35°C. Water plays an important role in promoting MO decomposition to form acetone. It is suggested that diacetone alcohol plays a role in the transformation of MO to acetone. The thermal reaction of pinacol on TiO2 mainly produces pinacolone at a temperature higher than 100°C. However, acetone is mainly formed in the photocatalytic decomposition of pinacol on TiO2 in O2. Pinacolone is thermally transformed into 2,3‐dimethyl‐1,3‐butadiene in the absence of O2 and into pivalate in the presence of O2. Both the reactions of pinacolone occur above 200°C. [ABSTRACT FROM AUTHOR]

Acetone is generated upon mesityl oxide (MO) adsorption on TiO2 at 35°C. Water plays an important role in promoting MO decomposition to form acetone. It is suggested that diacetone alcohol plays a role in the transformation of MO to acetone. The thermal reaction of pinacol on TiO2 mainly produces pinacolone at a temperature higher than 100°C. However, acetone is mainly formed in the photocatalytic decomposition of pinacol on TiO2 in O2. Pinacolone is thermally transformed into 2,3‐dimethyl‐1,3‐butadiene in the absence of O2 and into pivalate in the presence of O2. Both the reactions of pinacolone occur above 200°C. [ABSTRACT FROM AUTHOR]

Mesityl oxide is an important product of organic synthesis, which is used in the manufacture of pharmaceuticals and as a solvent. The demand for mesityl oxide is growing, which determines the need for further improvement of its production. The disadvantages of the traditional methods of obtaining mesityl oxide are low values of reagent conversion and selectivity. To eliminate them, it is proposed to obtain mesityl oxide in a combined reaction-rectification process. The combination of chemical transformation and separation of the resulting reaction mixture by means of rectification in one apparatus allows for a continuous withdrawal of the formed products from the reaction zone, which increases the rate of the target reaction, conversion and selectivity. In accordance with the modern strategy for the development of chemical-technological processes, the collection and processing of physical and chemical information on the properties of the components and mixtures contained in the reaction system was performed. Based on the experimental data, the parameters of the phase equilibrium model are determined, and its adequacy is estimated. The phase equilibrium model was used to construct a distillation diagram, to verify its consistency, and to conduct computational studies of the reaction-rectification process. The thermochemical parameters of the target reactions are calculated, the equilibrium constants are determined, and their temperature dependence is established. On the basis of the analysis of the literature data, a kinetic model of the process is proposed, and the conditions favorable for the course of the desired chemical transformation are determined with the use of this model. The obtained data are necessary for carrying out the analysis of the statics, constructing the basic technological scheme and calculating its static parameters.

Development and improvement of industrial technologies based on the principle of combining reaction and mass exchange processes is an urgent task. This is due to their advantage over the traditional sequential way of performing the chemical transformation and separation of the resulting reaction mixture. In reaction-rectification processes, the conversion of the process, the rate of reaction and selectivity may be increased due to continuous withdrawal of the formed products from the reaction zone. In addition, capital and energy costs in such processes are significantly reduced due to the reduction or even complete absence of external recycling in them. The modern method of developing reaction-rectifying processes is the analysis of statics, which allows isolating the limiting stationary states corresponding to the maximum yield of the target product. An essential disadvantage limiting the possibility of using this method for solving practical problems is the consideration of a single chemical reaction in its framework. At the same time, when passing to real processes, as a rule, this restriction is violated. The article offers a number of original approaches designed in the form of an algorithm that allows the analysis of statics to be extended to reaction-rectification processes with an unlimited number of components forming the reaction mixture and an unlimited number of chemical reactions taking place between them. On the basis of this algorithm, a ChIM program was developed in the SciLab environment, which makes it possible to single out sets of limiting stationary states of a combined process characterized by maximum reagent conversion values, selectivity and yield of the target product. The procedure for using the ChIM program is illustrated by the example of the industrial process for obtaining mesityl oxide from acetone. Calculations conducted using the software package Aspen Plus proved the possibility of practical implementation of limiting stationary state providing the maximum yield of mesityl oxide, which was predicted by using of ChIM.

Liquid–liquid equilibria (LLE) data for {water + 1-butanol + isophorone} and {water + 1-butanol + mesityl oxide} ternary systems were investigated systematically at different temperatures under atmospheric pressure. The Othmer–Tobias and Bachman equations were applied to analyze the dependability of the experimental LLE data. Selectivities and distribution coefficients were used to evaluate the extractive efficiency of the extractants. The Non-Random Two Liquid (NRTL) and Universal Quasi-Chemical (UNIQUAC) models were applied to correlate the studied systems and were well represented with all root mean square deviations (RMSD) less than 0.2%. Meanwhile, binary interaction parameters among these compounds were acquired during the correlation process. [ABSTRACT FROM AUTHOR]

• Pt/TiO 2 catalyzed condensation produces >95% of MIBK + DIBK. • Conversion with Pt/TiO 2 increase from 12 to 42% in presence of H 2. • Ni/TiO 2 is highly selective for α,β-unsaturated ketones. • No deactivation observed under reductive conditions, neither for Pt nor Ni. • Ni/TiO 2 mainly yields unsaturated C9s under reducing conditions. A stable performance of TiO 2 catalysts for gas-phase acetone aldol condensation was observed when reduced metals were added (Pt or Ni, 1.5 wt%) and the reactions were conducted in presence of hydrogen. In both cases, the resulting metal-loaded catalysts are stable for 10 h, whereas continuous deactivation is observed for the parent TiO 2 catalyst (573 K). Both the activation of the H 2 molecule by metal nanoparticles and the change of the catalytic surface by metal insertion (in the case of Ni-loaded catalyst) enable suppressing oligomerization (by hindering enolates formation) and the strong adsorption of intermediates (by decreasing the concentration of high-strength acid-basic active sites), respectively. More interestingly, these metals allow to tune the selectivity of the reaction. Indeed, the Ni-loaded titania catalyst is highly selective for the synthesis of α,β-unsaturated ketones (selectivity to unsaturated C6 and C9 species >98%, at ∼12% acetone conversion), whereas the Pt-loaded one is highly selective to the formation of saturated C6 and C9 ketones (MIBK and DIBK, with selectivities >95% at ∼42% acetone conversion). The catalytic activity and stability of the two materials (Ni/TiO 2 and Pt/TiO 2) in both absence and presence of H 2 are compared between them and with those of the parent TiO 2. The results obtained by the reaction gas-phase analysis are supplemented through different solid characterization techniques (i.e. , CO 2 -TPD and NH 3 -TPD, HRTEM, XPS, TPO, and DRIFTS). [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • ATR dual-comb spectroscopy (DCS) of pure liquids matches a spectral database. • Real-time quantification of liquid-phase chemical reactions using ATR DCS. • This work is an initial step towards evanescent DCS monitoring of micro-reactors. Abstract We combine mid-infrared dual-comb spectroscopy with attenuated total reflectance measurements to provide in-situ monitoring of a chemical reaction. The mid-infrared dual-comb spectrometer measures quantitative absorption cross-sections of mesityl oxide and diacetone alcohol in the region of 3300–2700 cm−1 (3.0–3.7 μm). Based on these spectra, the system is then used to monitor the hydration of mesityl oxide to diacetone alcohol from which we extract reaction kinetics values. This work shows the potential of dual comb systems to measure and monitor reactions in the condensed phase. [ABSTRACT FROM AUTHOR]

[Display omitted] • Reaction of aniline with acetone and mesityl oxide as a model carbonyl donor in acid catalysed Scraup-type condensation was studied. • Two type of heterogeneous organosulfonic acid modified silicas (amorphous and well-ordered) was applied as a catalysts. • Condensation of aniline with acetone and mesityl oxide to 1,2-dihydroquinoline derivatives proceeds in mixed Scraup/Doebner protocol. • Reaction pathway, mechanism and formation of intermediate and by-products are discussed in detail. This paper presents investigation on the synthesis of 2,2,4-trimethyl-1,2- H -dihydroquinoline (TMQ) as a result of the reaction of aniline and both acetone and mesityl oxide in the presence of selected sulfonic acid silica catalysts. Condensation of aniline with acetone is very complex process with the formation of significant number of side products, both desirable and undesirable considering the final product (TMQ). In acidic conditions and elevated reaction temperature the reactivity of main raw materials (aniline, acetone) is significantly high, what causes the formation of many side by-products lowering the selectivity of this reaction. In this paper the reaction of aniline with acetone in the presence of heterogeneous acidic silica catalysts were investigated in more detail and discussed. The results were confirmed by GC/MS analysis, that the presence of TMQ isomers and other by-products significantly affected the formation of final product. The formation of previously not described structural isomer of TMQ has been also demonstrated. [ABSTRACT FROM AUTHOR]

• The LLE data for water + mesityl oxide + solvents were measured. • The distribution coefficient and separation factor were calculated. • The NRTL and UNIQUAC models were applied to correlate the LLE data. • The UNIFAC model was used for LLE data prediction and comparison with experimental data. • The interaction forces between solvent and solute molecules were analyzed by the Dmol3 module. Mesityl oxide (MO) is a crucial organic synthesis intermediate and a popular high boiling point solvent. However, during its production process, wastewater containing MO is easily generated. To recover MO from wastewater, four alkanols with different carbon chain lengths (C6-C9) were chosen as extractants for the separation of MO from water. Liquid-liquid equilibrium (LLE) data for the ternary mixture of extractants + MO + water was experimentally measured at 303.2 K and 101.3 kPa. The separation factor (S) and distribution coefficient (D) were used to evaluate the extraction performance of the four extractants in separating MO from water. The results showed that 1-nonanol exhibited higher S and D values compared to other extractants, indicating its suitability as an effective extractant. The NRTL and UNIQUAC models were used to correlate the experimental data and determine the regression parameters. According to the mixing surface analysis based on the Gibbs energy topology, the binary interaction parameters are found to be consistent with the measured data. The UNIFAC model was used for predicting LLE data and comparing the results with the experimental data. The root mean square deviation (RMSD) was lower than 0.0077, 0.0075, and 0.0211 in these three models, respectively. In addition, differences in extractant extraction effects were analyzed by intermolecular interactions (σ-Profile, interaction energy, and hydrogen bond length). [ABSTRACT FROM AUTHOR]

Bis(trimethylsilyl) hypophosphite reacts with unsaturated ketones (methyl vinyl ketone and mesityl oxide) to give, depending on the reaction conditions, 1 : 1 or 1 : 2 adducts after hydrolysis. It was found that the intramolecular cyclization of the 1 : 2 reaction product with mesityl oxide, trimethylsilyl bis(2-methyl-4- oxopentan-2-yl)phosphinate, yields, after hydrolysis, a phosphorinane with exocyclic carbonyl and hydroxyl groups. [ABSTRACT FROM AUTHOR]

The extractant has a great influence on the performance and economy of the Phenols Recovery processes for treating coal-gasification wastewater. Meanwhile, computer-aided screening techniques have been applied to discern candidate solvents from the molecular perspective. In this paper, mesityl oxide, as a novel extractant, is found with high phenols removal efficiency through quantum chemical calculations. To confirm that, the removal performance with three different solvents (diisopropyl ether (DIPE), methyl isobutyl ketone (MIBK) and mesityl oxide) are investigated and compared via multi-stage counter-current extraction experiments. The experimental results identified that the performance using mesityl oxide as solvent is better than that using DIPE and MIBK. The total phenols concentration can be reduced from more than 5000 mg/L to less than 250 mg/L. Then, Phenols Recovery process using mesityl oxide as solvent is developed and conceptual designed. In view of the better performance and lower cost, mesityl oxide is a very promising extractant for the removal of phenols. [ABSTRACT FROM AUTHOR]

In this work, liquid-liquid equilibrium (LLE) data for the water + propionic acid or butyric acid + mesityl oxide ternary systems were measured at (298.2 and 323.2) K under atmospheric pressure. The reliability of the experimental tie-line data was verified by the Othmer-Tobias and Hand equations. The distribution coefficient and selectivity, calculated from the LLE data, showed high efficiency for mesityl oxide extracting propionic or butyric acid from the aqueous solution. A comprehensive comparison with various other extractants not only confirmed the high extraction efficiency of mesityl oxide, but also revealed some general guide lines for further screening extractants for carboxylic acids. The experimental data were successfully correlated by both UNIQUAC and NRTL models, yielding binary interaction parameters for relevant process simulations. [ABSTRACT FROM AUTHOR]

In this work, liquid-liquid equilibrium (LLE) data for the ternary systems, mesityl oxide + o -, m -, p -cresol + water, were determined at 333.2 K and 353.2 K under 101 kPa. The high distribution coefficient and selectivity calculated by the experimental tie-line data indicate excellent efficiency for mesityl oxide extracting cresols from aqueous solutions. The NRTL and UNIQUAC models were used to correlate the experimental LLE data, with root mean square deviations (RMSDs) below 2.1% and 1.5%, respectively. The COSMO-SAC model was also employed to calculate the LLE data, which agreed with the experimental results quite well. [ABSTRACT FROM AUTHOR]

A capillary gas chromatography method with a short run time, using a flame ionization detector, has been developed for the quantitative determination of trace level analysis of mesityl oxide and diacetone alcohol in the atazanavir sulfate drug substance. The chromatographic method was achieved on a fused silica capillary column coated with 5% diphenyl and 95% dimethyl polysiloxane stationary phase (Rtx-5, 30 m x 0.53 mm x 5.0 µm). The run time was 20 min employing programmed temperature with a split mode (1:5) and was validated for specificity, sensitivity, precision, linearity, and accuracy. The detection and quantitation limits obtained for mesityl oxide and diacetone alcohol were 5 µg/g and 10 µg/g, respectively, for both of the analytes. The method was found to be linear in the range between 10 µg/g and 150 µg/g with a correlation coefficient greater than 0.999, and the average recoveries obtained in atazanavir sulfate were between 102.0% and 103.7%, respectively, for mesityl oxide and diacetone alcohol. The developed method was found to be robust and rugged. The detailed experimental results are discussed in this research paper. [ABSTRACT FROM AUTHOR]

Highlights: [•] Solid acids were firstly used for the alkylation of 2-MF with mesityl oxide. [•] Nafion-212 resin exhibited the best performance among the investigated catalysts. [•] The high efficiency of Nafin-212 resin can be explained by its strong acidity. [•] Ni–Mo2C/SiO2 was used for the first time in the HDO of biomass derived oxygenates. [•] Higher yield of diesel range alkanes was obtained by the HDO over Ni–Mo2C/SiO2. [Copyright &y& Elsevier]

The aldol condensation reaction over sulfated zirconia led to the production of diacetone alcohol, which was further dehydrated forming mesityl oxide. The sulfated zirconia was obtained from zirconium acetate ethane sulfonate as a single source precursor. Oxides were obtained by calcinations of the precursors at 550-650 °C, while the self-condensation reaction of acetone was carried out at 150 °C. The precursor and the produced oxides were characterized using various characterization techniques. The precursors were synthesized with different acetate to ethane sulfonate ratio, ranging from 1 to 3. The major products obtained from the condensation reaction over the resulted oxide were mesityl oxide, mesitylene isophorone, naphthalene, and pentamers. The selectivity of mesityl oxide was approximately 100 % at the initial time-on-stream. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Aldol condensation of acetone was studied over solid base CaO-SnO catalyst in the 300-450 °C temperature range and at 15-75 atm pressure in a fixed-bed reactor. The main products are mesityl oxide and isophorone. The high stability of CaO-SnO catalyst performance was observed at pressure of 75 atm giving the acetone conversion of 36-41%. Increase in the temperature and pressure led to a simultaneous raise in acetone conversion. The maximum conversion of 41% was achieved at 400 °C, 75 atm and a flow rate of acetone of 8.1 g h (g catalyst). [ABSTRACT FROM AUTHOR]

Abstract: We demonstrate the applicability of a new reactive distillation configuration, i.e. reactive distillation with side draw, for certain industrially important reactions. For the reacting systems which involve products with intermediate volatility, a side draw facilitates its in situ removal and enhances either conversion or selectivity. It further reduces the downstream processing in some cases. The concept is proved for three representative systems, viz. esterification of lactic acid, aldol condensation of acetone and for esterification of fatty acid by methanol. Experimental proof is also provided in some cases. [Copyright &y& Elsevier]

Abstract: Dimerization of acetone (Ac) yields diacetone alcohol (DAA), which on further dehydration gives mesityl oxide (MO) along with various side-products. The reacting system is a combination of various series and parallel reactions. In the present work, the reaction is studied using a cation exchange resin (Amberlyst ) as catalyst. The effect of catalyst loading and temperature on reaction kinetics was evaluated and three models based on simplified Langmuir–Hinselwood mechanism are proposed. Aim of the work is to minimize undesired side-products and understand the effect of different parameters and operating modes on DAA:MO product ratio in reactive distillation (RD). It has been shown that the reaction when operated in a reactive rectification mode offers flexibility in the relative production rates of DAA and MO. The experimental results obtained are explained by simulation. [Copyright &y& Elsevier]

Abstract: The kinetics of one-step synthesis of methyl isobutyl ketone from acetone was studied in the presence of the bifunctional commercial ion exchange resin, Amberlyst CH28 over a wide range of temperature, total pressure and catalyst loading in a batch reactor. An activity-based kinetic model is proposed to predict the observed results, with the non-idealities of the liquid phase being described using the UNIQUAC method. Formation of mesityl oxide was found to govern the overall rate of reaction. Low reaction rates were observed at higher conversion, possibly due to a pseudo-equilibrium caused by reversible deactivation of the catalyst as a result of formation of water in the reaction system. Simultaneous removal of water during the course of the reaction may result in an enhanced conversion. [Copyright &y& Elsevier]

Abstract: The condensation and selective hydrogenation of acetone to methyl isobutyl ketone (MIBK) was studied on a directly comparable series of 0.1–1.5wt% Pd and Pt catalysts supported on hydrotalcite (HT)-derived Mgoxides in a liquid-phase batch micro-reactor at 99–153°C and 400psig. The support catalyzes the condensation of acetone to diacetone alcohol (DAA) and its subsequent dehydration to mesityl oxide (MO); Pd and Pt catalyze the selective hydrogenation of MO to MIBK. The net yield of MIBK is independent of metal type and loading, depending only on the wt% of exposed metal. However, the by-products are quite different-Pt/HT is more selective for the direct hydrogenation to isopropanol (IPA) while Pd/HT forms more of the intermediate diacetone alcohol (DAA). Among the Pd- and Pt-based catalysts examined, the 0.1wt% Pd/HT gives the maximum MIBK yield of ∼32%, with an unusually low selectivity to IPA, 0.6mol% compared to 15mol% for the next best catalyst. This appears to be due to its higher basicity, and (to a lesser extent) to its minimal concentration of metal sites. This metal loading is sufficient to fully hydrogenate mesityl oxide to MIBK, and it also shows minimal acetone hydrogenation to isopropanol. A study of physically mixed Pd/silica+HT versus Pd/HT shows that the acid/base and hydrogenation functions need not be molecularly close. [Copyright &y& Elsevier]

Abstract: The liquid phase kinetics for the selective hydrogenation of mesityl oxide (MO) to methyl isobutyl ketone (MIBK) in acetone over a 0.52wt% catalyst was studied in a 300mL Parr autoclave operating in semibatch mode at , initial MO concentrations ranging from 0.1 to 1.0M and hydrogen partial pressures ranging from 1.50 to 4.23MPa. The reaction was found to be first order in hydrogen partial pressure and a non-linear dependence on MO concentration was observed. An average MIBK selectivity of about 94.5% between 0.2 and 1.0M initial MO concentration was obtained due to a competitive hydrogenation of acetone to 2-propanol. A mechanistic kinetic model was developed following the Langmuir–Hinshelwood approach from the assumptions that only diadsorbed MO participates in the hydrogenation reaction while MO adsorbed at a single site acts as an adsorbing inert. The addition of adsorbed hydrogen atoms is stepwise with the second addition of the adsorbed hydrogen atom being the rate-determining step. The proposed kinetic model was validated using initial rate data obtained from the kinetic experiments and showed the strongest statistical significance when compared to other models reported in the literature, suggesting that the proposed mechanism is reasonable. [Copyright &y& Elsevier]

Acetone condensation was carried out over high surface area molybdenum nitride and carbide catalysts. Rates and selectivities for these materials were compared to those for MgO (a solid base catalyst), USY (a solid acid catalyst) and 1% Pt/SiO2 (a supported noble metal catalyst). The Mo2N catalyst as well as MgO and USY catalyzed the condensation of acetone to products including mesityl oxide (MO), mesitylene and isophorone. Areal rates for the Mo2C and Mo2N catalysts were higher than those for the MgO and USY catalysts. The Mo2N catalyst was most active for mesityl oxide production. The formation of mesitylene and isophorone over this catalyst indicated that Mo2N possessed strong acid and base sites, respectively. Results from the thermal desorption of CO2 and NH3 confirmed the presence of these sites. The hydrogenation of acetone to isopropanol (IPA) and its subsequent dehydration to propylene were predominant reactions for the Mo2C and 1% Pt/SiO2 catalysts. Differences between the Mo2N and Mo2C catalysts are explained based on their base, acid and metallic properties. [Copyright &y& Elsevier]

Synthesis of 2,2-dimethyl-4-formyl-7-methoxy-(2H)-1-benzopyran has been achieved by a three step reaction sequence, wherein the key step has been the preparation of 7-hydroxy-2,2,4-trimethyl-(2H)-1-benzopyran by a novel condensation reaction between resorcinol and mesityl oxide in presence of polyphosphoric acid (PPA). [ABSTRACT FROM AUTHOR]

5-Amino-4,6-dicyano-3-dicyanomethylene-1,8,8-trimethyl-2-azabicyclo[2.2.2]oct-5-ene has been synthesized. The molecular and crystal structure of this compound has been determined. [ABSTRACT FROM AUTHOR]

[Display omitted] • The LLE data for water + cyclohexanone + mesityl oxide were measured at 298.2, 303.2 and 313.2 K under 101.3 kPa. • The distribution coefficient and separation factor were calculated. • The NRTL and UNIQUAC models were applied to correlate the experimental LLE data. • The binary interaction parameter values were obtained from the data correlation. • The GUI-MATLAB tool was used to check the consistency of the binary parameters of the NRTL and UNIQUAC models. To separate and purify cyclohexanone from water, in 101.3 kPa, 298.2, 303.2 and 313.2 K, the liquid–liquid equilibrium (LLE) data of the ternary mixture of water + cyclohexanone (CYC) + mesityl oxide were presented. The distribution coefficient (D) and separation factor (S) appraised the utility of extracting cyclohexanone from water. The NRTL and UNIQUAC models successfully correlated the experimental data with RMSD less than 0.29%. The GUI-MATLAB tool was used to verify the good reliability of the regression parameters. [ABSTRACT FROM AUTHOR]

Mesityl oxide is standardly used to produce methyl iso butyl ketone but it can be also used to produce other useful compounds. Three catalysts were used for the reaction of the mesityl oxide reduction. They were NiW, NiMo, and CoMo supported on phonolite modified by HCl (metals/Ph-HCl). The fresh catalysts were characterized by XRD, XRF, BET surface, Hg porosimetry, SEM, H2-TPR, NH3-TPD, CO2-TPD. The materials were directly used, previously reduced in H2 or sulfided for the mesityl oxide reduction under H2 atmosphere. The reaction was performed in an autoclave at T = 375 °C, p = 50 bar (H2), and TOS = 1.5 h. The products were analyzed by GC/MS, GC/FID-TCD, ATR. The main products were methyl isobutyl ketone, 2-methyl pentane, and 2-methyl-2-pentene. Sulfided metal catalysts were the most active in the methyl isobutyl ketone, where the NiWSx/Ph-HCl catalyst showed the highest activity. For the non-previously-activated and hydrogen activated catalysts the most active catalyst was the NiMo/Ph-HCl for the production of methyl isobutyl ketone. The catalyst CoMo/Ph-HCl activated in hydrogen was the most active for the production of 2-methyl pentane compared to the other two hydrogen-activated materials. [ABSTRACT FROM AUTHOR]

• Electropolymerisation of phenol on platinum has identical properties. • Timescale of experiments affects the electropolymerisation of phenol on platinum. • Spectroscopic investigations show formation of composite polymers at both electrodes. • Low permeability compact deposits form on glassy carbon. In this paper, electrochemical polymerization of phenol in mesityl oxide on platinum and glassy carbon electrodes by voltammetric oxidation is discussed. The electrochemically formed phenoxyl radicals initiated the polymerization of solvent molecules. In mesityl oxide without any added phenol there was no significant film formation but glassy carbon electrode deactivated. On platinum electrode, a polymer layer with high porosity could be obtained in solution of phenol prepared with mesityl oxide. On glassy carbon electrode, the electrodeposition resulted in a compact polymer. The micro-Raman investigations demonstrated the presence of units of mesityl oxide in the formed film. [ABSTRACT FROM AUTHOR]

4,6,6-Trimethyl-1,4-dihydropyrimidines have been synthesized by condensation of 2-quinazolylguanidines with mesityl oxide. The analogous reaction with benzalacetone leads to unstable 4-methyl-6-phenyl-1,4-dihydropyrimidines, which are oxidized to the corresponding 4-methyl-6-phenylpyrimidines. [ABSTRACT FROM AUTHOR]

Protein precipitation in acetone is frequently employed ahead of mass spectrometry for sample preconcentration and purification. Unfortunately, acetone is not chemically inert; mass artifacts have previously been observed on glycine-containing peptides when exposed to acetone under acidic conditions. We herein report a distinct chemical modification occurring at the level of intact proteins when incubated in acetone. This artifact manifests as one or more satellite peaks in the MS spectrum of intact protein, spaced 98 u above the mass of the unmodified protein. Other artifacts (+84, +112 u) also appear upon incubation of proteins or peptides in acetone. The reaction is pH-sensitive, being suppressed when proteins are exposed to acetone under acidic conditions. The +98 u artifact is speculated to originate through an intermediate product of aldol condensation of acetone to form diacetone alcohol and mesityl oxide. A +98 u product could originate from nucleophilic attack on mesityl oxide or through condensation with diacetone alcohol. Given the extent of modification possible upon exposure of proteins to acetone, particularly following overnight solvent exposure or incubation at room temperature, an awareness of the variables influencing this novel modification is valued by proteomics researchers who employ acetone precipitation for protein purification.