Swelling and dissolution behavior of poly(methyl methacrylate) films in methyl ethyl ketone/methyl alcohol mixtures studied by optical techniques

Swelling and dissolution behavior of poly(methyl methacrylate) (PMMA) films during unidimensional penetration of methyl ethyl ketone/methyl alcohol (MEK/MA) liquid mixtures at 22°C is presented. Optical microscopy and two‐beam interferometry were applied to clamped PMMA films to obtain information on penetration kinetics and penetrant concentration profiles. Dissolution by pure MEK was initially controlled by Case II penetration kinetics and at later stages of the process, by stress cracking in the absence of a surface layer. Introduction of increasing amounts of MA in the liquid solvent resulted in moderation of the fragmentation process, enhanced penetration rates at the early stages of the process, deviations from Case II kinetics at the later stages, and the existence of a surface layer. These results indicate that penetration of MEK/MA mixtures and dissolution of PMMA are characterized by lower diffusion Deborah, and higher dissolution, numbers compared to those of pure MEK. Swelling by pure MA, as well as by nonsolvent MEK/MA mixtures, was characterized by Case II penetration kinetics. A pronounced minimum in the penetration rate versus liquid mixture composition plot was observed at 30 : 70 v/v MEK/MA composition. Laser interferometry was applied to very thin PMMA films, supported on a silicon substrate, to study selected cases. The results obtained were very similar to those obtained by optical microscopy. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2823–2834, 2002; DOI 10.1002/app.10258     

Comparison of dissolution and mutual diffusion coefficients during dissolution of poly(methyl methacrylate) films

Steady state fluorescence measurements have been used for studying the dissolution of polymer films. These films are formed by free radical polymerization of methyl methacrylate (MMA) in which pyrene ( P_y ) was introduced as a fluorescence probe. Dissolution of poly(methyl methacrylate) (PMMA) films in chloroform–heptane mixtures were monitored in real-time by the P_y fluorescence intensity change. Dissolution coefficients D_d of P_y molecules were measured during dissolution of PMMA films, and found to be about 10⁻⁶ cm² s⁻¹. After dissolution, fluorescence quenching measurements were performed and the Stern–Volmer equation was employed to measure the mutual diffusion coefficients of heptane (D_h) and P_y (D_Py) molecules; these were found to be about 10⁻⁵ cm² s⁻¹. © 1999 Society of Chemical Industry     

Dissolution rates of poly(methyl methacrylate) films in mixed solvents

A laser interferometer has been used to measure in situ the dissolution rates of thin films of poly(methyl methacrylate) (PMMA). The most significant finding is that addition of small amounts of a low-molecular weight nonsolvent can increase the rate obtained with a higher molecular weight solvent. In this study, silicon wafers were coated with polymer (about 1 μm thick) and annealed at 155°C for 1 h. The dissolution rates were measured at 17.5, 22.5, and 27.5°C. All the mixtures contained methyl ethyl ketone (MEK) (2-butanone), as the major component. The minor component was water, methanol, ethanol, 1-propanol, 2-propanol, or ethylene glycol. Water and methanol showed the greatest effects. Both were able to increase the dissolution rate as much as two-fold. All the mixtures exhibit the same activation energy (25 kcal/mol) despite their wide differences in dissolution rate.     

Studies of reactions with polymers. III. Syntheses and properties of poly(vinyl alcohol) graft terpolymers

A condensation-coupling reaction through esterification is performed between the hydroxy groups of poly(vinyl alcohol) (PVA) and the anhydride groups of methyl methacrylate (MMA)-co-maleic anhydride (MA) copolymer to produce the PVA-g-MMA/MA graft terpolymer. The MMA-co-MA copolymer was obtained by copolymerization of MA and MMA in dimethyl sulfoxide by using azobisisobutyronitrile as initiator. The structure of reaction products was confirmed by infrared analysis, and the dependence of composition, viscosity, and yield of the graft terpolymer on the MA content in MMA-co-MA as well as the concentration of the reactants fed were investigated. Mechanical properties, water content, and gel content of the membranes of terpolymers were measured over a wide range of compositions. PVA-g-MMA/N-ethylol maleimide was also synthesized by reacting the residual anhydride groups on PVA-g-MMA/MA with ethanol amine, this reaction proceeds through the PVA-g-MMA/N-ethylol maleamic acid intermediate.     

Effects of molecular weight and plasticization on dissolution rates of thin polymer films

The dissolution rates (DR) in methyl ethyl ketone (MEK) of thin films of poly(methyl methacrylate), (PMMA), were measured using interferometry. Films were spun on silicon-oxide coated wafers. After baking at 155°C for one hour the dry films were about 1 μm thick. PMMA samples with M_n of 6000 to 320 000 were prepared by (a) polymerization and fractionation, and (b) electron beam bombardment of coated wafers. Both preparations resulted in non-linear behaviour when log DR was plotted against log M_n. The irradiated samples uniformly had DR values that were about 2.5 × those of the unexposed samples of the same M_n. Plasticization of PMMA by poly(ethylene oxide), PEO, of M_n = 4000 also changed DR in direct proportion to the amount of PEO added. With a weight fraction of 0.2 PEO, the DR was double that for PMMA alone.     

Ketone Extraction of Mixed Chloride-Bisulfate Complexes of Aluminum

Abstract

The partition ratio D of Al(III) between aqueous chloride/bisulfate solutions of constant ionic strength (5.0) and methyl ethylketone (MEK) or methyl isobutyl ketone (MIBK) was investigated radiometrically as a function of the chloride/bisulfate ratio and aqueous acidity. With MIBK, the plot of D vs chloride/bisulfate showed a maximum. Results may be explained by assuming the extraction of the following species: KtH⁺·AlCl₄-, KtH⁺-AlCl₂(HSO₄)₂- and KtH⁺·Al(HSO₄)₄, where KtH⁺ represents a solvated hydrogen ion. Formation constants for these complexes were calculated.     

Aqueous polymerization of methyl methacrylate initiated by ceric ion reducing agent systems in sulfuric acid medium

Polymerization of methyl methacrylate (MMA) was carried out in aqueous sulfuric acid medium at 30°C using ammonium ceric sulfate (ACS)/methyl ethyl ketone (MEK) and ammonium ceric sulfate/acetone as redox initiator systems. A short induction period was observed with both the initiator systems, as well as the attainment of limiting conversion for polymerization reactions. The rate of ceric ion consumption, R_ce, was first order with respect to Ce(IV) concentration in the concentration range (0.5–5.5) × 10⁻³M, and 0.5 order with respect to reducing agent concentration in the concentration ranges (0.0480–0.2967M) and (0.05–0.3912M) for Ce(IV)–MEK and Ce(IV)–acetone initiator systems, respectively. A fall in R_ce was observed at higher reducing agent concentrations. The plots of R_ce versus reducing agent concentrations raised to the half power yielded straight lines passing through the origin, indicating the absence of complex formation between reducing agents and Ce(IV). The addition of sodium sulfate to maintain constant sulfate ion concentration in the reaction medium could bring down the R_ce values in the present reaction systems. The rate of polymerization of MMA, R_p, increased with increase in Ce(IV), reducing agent, and monomer concentrations for the Ce(IV)–MEK initiator. The rate of polymerization of MMA is independent of Ce(IV) concentration and increased with an increase in reducing agent and monomer concentrations for the Ce(IV)–acetone initiator. At higher concentrations of reducing agent (0.4–0.5M), a steep fall in R_p values was observed with both the initiator systems. The orders with respect to Ce(IV), MEK, and MMA using the Ce(IV)–MEK initiator were found to be 0.23, 0.2, and 1.29, respectively. The orders with respect to Ce(IV), acetone, and MMA using the Ce(IV)–acetone initiator were found to be zero, 0.42, and 1.64, respectively. Maintaining constant [SO²⁻₄] in the reaction medium could bring down R_p values for the Ce(IV)–MEK initiator system. On the other hand, a rise in R_p values with an increase in [Na₂SO₄] could be observed when constant [SO²⁻₄] was maintained in the reaction medium for the Ce(IV) on reducing agent, production of radicals, initiation, propagation, and termination of the polymeric radicals by bimolecular interaction is proposed. An oxidative termination of primary radicals by Ce(IV) is also included. © 1996 John Wiley & Sons, Inc.     

Effects of addition of acrylic compatibilizer on the morphology and mechanical behavior of amorphous polyamide/SAN blends

Amorphous polyamide (aPA)/acrylonitrile‐styrene copolymer (SAN) blends were prepared using methyl methacrylate‐maleic anhydride copolymer MMA‐MA as compatibilizer. The aPA/SAN blends can be considered as a less complex version of the aPA/ABS (acrylonitrilebutadiene‐styrene) blends, due to the absence of the ABS rubber phase in the SAN material. It is known that acrylic copolymer might be miscible with SAN, whereas the maleic anhydride groups from MMA‐MA can react in situ with the amine end groups of aPA during melt blending. As a result, it is possible the in situ formation of aPA‐g‐MMA‐MA grafted copolymers at the aPA/SAN interface during the melt processing of the blends. In this study, the MA content in the MMA‐MA copolymer and its molecular weight was varied independently and their effects on the blend morphology and stress–strain behavior were evaluated. The morphology of the blends aPA/SAN showed a minimum in the SAN particle size at low amounts of MA in the compatibilizer, however, as the MA content in the MMA‐MA copolymer was increased larger SAN particle sizes were observed in the systems. In addition, higher MA content in the compatibilizer lead to less ductile aPA/SAN blends under tensile testing. The results shown the viscosity ratio also plays a very important role in the morphology formation and consequently on the properties of the aPA/SAN blends studied. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Methyl methacrylate based copolymers and terpolymers: Preparation,identification, and plasticizing capability for a poly(methyl methacrylate) used in aviation

In this study, we first synthesized transparent poly(methyl methacrylate–maleic anhydride) [P(MMA–MAH)] and poly(methyl methacrylate–maleic anhydride–N‐2‐methyl‐4‐nitrophenyl maleimide) [P(MMA–MAH–MI)] via free‐radical polymerization at different monomer ratios. The synthesized polymers were characterized by titration, viscometric, spectroscopy, and thermal analyses. Higher contents of maleic anhydride (MAH) resulted in increases in the viscosity, glass‐transition temperature (T_g), and transparency. The synthesized polymers were then blended with a commercial‐grade poly(methyl methacrylate) (PMMA) used in aviation in the presence of CHCl₃. According to the free volume theory, the incorporation of 5 wt % P(MMA–MAH)s or P(MMA–MAH–MI)s into the commercial PMMA resulted in a plasticizing impact on this thermoplastic, which was confirmed by the decrease in the T_g values of the blends with almost the same transparency as the initial PMMA. In fact, the higher the content of MAH was, the lower the T_g of the blends was. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46603.     

Dissolution rates for thin films of miscible polymer blends

The dissolution rates of thin polymer films were measured and compared. Mixtures of various ratios of poly(methyl methacrylate), PMMA, and poly(p-hydroxystyrene), PPHS, were dissolved in methyl isobutyl ketone, MIBK. The polymer solutions were then spun into thin films on silicon wafers and dried. The coated wafers were immersed in an MIBK bath and the rate of dissolution was observed using laser interferometry. The results show that pure PPHS films have dissolution rates 1000 times greater than films of pure PMMA at comparable molecular weights. However, for films containing both PPHS and PMMA, a minimum dissolution rate occurs for a mixture with about 20% (by weight) PPHS. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 2015–2020, 1997     

Fast transient fluorescence technique (FTRT) for studying dissolution of polymer glasses

The fast transient fluorescence technique (FTRT) was used for studying the swelling and dissolution of a glassy polymer formed by free‐radical polymerization of methyl methacrylate (MMA). Anthracene (An) was introduced during polymerization as a fluorescence probe to monitor swelling and dissolution. Swelling and dissolution processes of disc‐shaped poly(methyl methacrylate) (PMMA) glasses in a chloroform–heptane mixture were monitored by measuring the fluorescence lifetimes of An from its decay traces. A method is developed for low quenching efficiencies for measuring lifetimes, τ, of An, and it was observed that τ values decreased as the dissolution process proceeded. Desorption, D, and mutual diffusion, D_m, coefficients of An molecules were measured during dissolution of PMMA and found to be around 5.4 × 10⁻⁶ (cm²/s) and 2.2 × 10⁻⁵ (cm²/s), respectively. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 948–957, 1999     

Synthesis and antitumor activity of poly(3,4‐dihydro‐2H‐pyran‐co‐maleic anhydride‐co‐vinyl acetate)

The radical‐initiated terpolymerization of 3,4‐dihydro‐2H‐pyran (DHP), maleic anhydride (MA), and vinyl acetate (VA), which were used as a donor–acceptor–donor system, was carried out in methyl ethyl ketone in the presence of 2,2′‐azobisisobutyronitrile as an initiator at 65°C in a nitrogen atmosphere. The synthesis and characterization of binary and ternary copolymers, some kinetic parameters of terpolymerization, the terpolymer‐composition/thermal‐behavior relationship, and the antitumor activity of the synthesized polymers were examined. The polymerization of the DHP–MA–VA monomer system predominantly proceeded by the alternating terpolymerization mechanism. The in vitro cytotoxicities of poly(3,4‐dihydro‐2H‐pyran‐alt‐maleic anhydride) [poly(DHP‐alt‐MA)] and poly(3,4‐dihydro‐2H‐pyran‐co‐maleic anhydride‐co‐vinyl acetate) [poly(DHP‐co‐MA‐co‐VA)] were evaluated with Raji cells (human Burkitt lymphoma cell line). The antitumor activity of the prepared anion‐active poly(DHP‐alt‐MA) and poly(DHP‐co‐MA‐co‐VA) polymers were studied with methyl–thiazol–tetrazolium testing, and the 50% cytotoxic dose was calculated. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2352–2359, 2005     

Preparation of poly(methyl methacrylate‐co‐maleic anhydride)/SiO2?TiO2 hybrid materials and their thermo‐ and photodegradation behaviors

The optically transparent poly(methyl methacrylate‐co‐maleic anhydride) P(MMA‐co‐MA)/SiO₂? TiO₂ hybrid materials were prepared using 3‐aminopropyl triethoxysilane as a coupling agent for organic and inorganic components. Real‐time FTIR was used to monitor the curing process of hybrid sol, indicating that imide group formation decreased with increasing titania content. scanning electron microscopy, atomic force microscopy, and differential scanning calorimetry results confirmed their homogeneous inorganic/organic network structures. TGA analysis showed that incorporated titania greatly prohibits the thermodegradation of hybrid films, especially at the content of 5.3 wt %, showing an increase of about 32.6°C at 5% loss temperature in air. The UV degradation behavior of P(MMA‐co‐MA) studied by quasi‐real‐time FTIR showed that TiO₂ incorporated in the hybrid network provides a photocatalytic effect rather than a UV‐shielding effect. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1714–1724, 2005     

Delaying the onset of macrogelation for the synthesis of branched and star-like polymers via conventional free-radical polymerisation: Binary solvent effects and incorporation of surfmers

It is known that the preferential solvation and conformation of a polymer in a solvent mixture are functions of the polymer's molecular weight and the solvent qualities. This paper demonstrates that these relationships can be exploited to delay the onset of macrogelation for branched poly(methyl methacrylate/ethylene glycol dimethacrylate) (p(MMA/EGDMA)) polymers and star-like poly(methyl acrylate/ethylene glycol dimethacrylate) (p(MA/EGDMA)) polymers synthesised via conventional free-radical polymerisation (CFRP) in a binary solvent mixture (consisting of a good solvent and a precipitant for the polymer). The gelation limits of the MMA/EGDMA and MA/EGDMA polymerisations in a methyl ethyl ketone (MEK)/heptane binary solvent mixture can be extended to regions of higher monomer concentration with increases in polymer yield between 13 and 50 ± 5 w/w% for the p(MMA/EGDMA) system and between 8 and 19 ± 6 w/w% for the p(MA/EGDMA) system across the gelation boundary. Thus, a facile method of increasing the concentration of batch reaction mixtures by the simple addition of small amounts of precipitant into the reaction solutions is presented. Furthermore, the gelation limits of both polymerisation systems in the binary solvent mixtures were further extended with increases in polymer yield between 11 and 17 ± 4%w/w for the p(MMA/ODA/EGDMA) system and between 8 and 20 ± 5%w/w for the p(MA/VS/EGDMA) system by the respective incorporation of octadecyl acrylate (ODA) and vinyl stearate (VS) surfmers into the polymers, demonstrating the application of steric hinderance to shield the propagating polymers from excessive cross-linking reactions.     

Polymer electrolyte membranes having sulfoalkyl grafts into ETFE film prepared by radiation‐induced copolymerization of methyl acrylate and methyl methacrylate

Polymer electrolyte membranes (PEMs) containing alkylsulfonic acid grafts can be prepared by radiation‐induced graft copolymerization of methyl acrylate (MA) and methyl methacrylate (MMA) into a poly(ethylene‐co‐tetrafluoroethylene) film followed by sulfonation of the MA units in the copolymer grafts using an equimolar complex of chlorosulfonic acid and 1,4‐dioxane (ClSO₃H‐Complex). PEMs with MA/MMA copolymer grafts that are 33%–79% MA units were prepared by preirradiation with a dose of 20 kGy and grafting in bulk comonomers at 60°C. The grafted films are treated with ClSO3H‐Complex to obtain PEMs with ion exchange capacity of 0.36‐0.81 mmol/g (sulfonation degrees of 20%–40%) and proton conductivity of 0.04‐0.065 S/cm. These values can be controlled by changing the MA content the sulfonation occurring at an α‐carbonyl carbon. The PEMs with higher MMA content showed higher durability in water (80°C) and under oxidative conditions (3% H₂O₂) at 60°C. This is because the PMMA grafts in the PEMs have no proton at an α‐carbonyl carbon, which is considered to be a trigger of the degradation of grafting polymers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation of interfacially compatibilized PP‐EPDM thermoplastic vulcanizate/graphite nanocomposites: Effects of graphite microstructure upon morphology,electrical conductivity,and melt rheology

Electrically conductive PP/EPDM dynamically crosslinked thermoplastic vulcanizate (TPV)/expanded graphite (EG) has been successfully prepared via melt compounding of maleic anhydride grafted polypropylene (PP‐g‐MA)/EG masterbatch and a commercially available TPV material. Correlation between graphite microstructure, and electrical conductivity as well as melt rheological behavior has been studied. Natural graphite flake (NGF), graphite intercalated compound (GIC), and exfoliated graphite (EG) have been employed and compared. Scanning electron microscopy (SEM) showed the presence of 100–200 nm nanolayers in the structure of PP‐g/EG masterbatches, whereas thinner platelets (1.5–2.5 nm) were revealed by transmission electron microscopy (TEM). Better dispersion of the graphite nanolayers in the microstructure of TPV/PP‐g‐MA/EG composite was verified, as the 7.3 Å spacing between the aggregated graphite nanolayers could not be observed in the XRD pattern of this material. TPV/PP‐g/EG nanocomposites exhibited much lower conductivity percolation threshold (φ_c) with increased conductivity to 10^?5 S/cm at EG wt % of 10. Higher nonlinear and nonterminal melt rheological characteristics of dynamic elastic modulus (G′) at low frequency region was presented by the TPV/PP‐g/EG nanocomposites, indicating the formation of nanoscopic conducting multiple networks throughout the continuous TPV matrix. Maleated PP was found to be much more effective in separating EG nanolayers which is attributed to the higher interfacial interaction between PP‐g‐MAH and EG, synergized with its multiporous structure. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Study on ketalization reaction of poly(vinyl alcohol) by ketones. IV. Reaction between poly(vinyl alcohol) and aliphatic ketones and behavior of polyvinylketal in water

Ketalization reaction of poly(vinyl alcohol) (PVA) by aliphatic ketones, dimethylsulfoxide (DMSO) as solvent, under the presence of acidic catalyst, in homogeneous system was carried out and the synthesis of polyvinylketals were successfully performed. The equilibrium constant at 40°C is ca. 0.07 in the case of methyl n-propyl ketone (nPK) and methyl n-butyl ketone (nBK), but is ca. 0.05 in the case of methyl i-propyl ketone (iPK) and ca. 0.01 in the case of methyl i-butyl ketone (iBK) and methyl t-butyl ketone (tBK), respectively. Moreover, the ketalization degree of polyvinylketal by iBK and tBK reached to only ca. 35 mol % as the maximum. It seems that these were due to steric hindrance of bulky side chain of ketones. But the heat of reaction is 7.5 kcal/mol in all aliphatic ketones, it seems to proceed the same ketalization reaction mechanism. Films prepared from the polyvinylketals were soaked in water and degree of swelling, solubility, and hydrolysis of films were measured. The reaction of film with water, in acidic side, at first the film swells, and then, as the deketalization reaction proceeds, the film dissolves in water. The dissolution time is controlled by the kind of ketones, ketalization degree, and pH of water which reveals that deketalization reaction proceeds proportional to proton concentration. It is more difficult to dissolve highly ketalized polyvinylketals obtained by propyl ketones and butyl ketones than that by acetone. The hydrolysis of polyvinylketal film proceeds in the order as follows: acetone > MEK > nPK > iPK ≒ nBK > iBK > tBK. This phenomenon seems to be affected by hydrophobicity of the film surface which depends upon the kind of the original ketones.     

Differential dissolution and electron-beam lithographic sensitivity of poly(methyl methacrylate)

Photolithographic and electron-beam integrated circuit fabrication techniques rely heavily upon differences in polymer resist dissolution (development) rates to produce circuit patterns. We have applied the wide-line NMR, technique, augmented by dynamic nuclear polarization, to the measurement of polymer dissolution rates of poly(methyl methacrylate), (PMMA). At high gamma-ray exposures, we find PMMA to have dissolution rates from 2X to 1000X those of unirradiated material. The highest radiation-enhanced dissolution rates are obtained with carbon tetrachloride-based developer solutions, whereas generally lower enhanced rates are observed with 1:3 acetone or methylethylketone/isopropanol standard developer. E-beam line exposures are developed in PMMA and poly(ethyl methacrylate), PEMA, resists using similar developers for comparison. Using straight CCl₄ as a developer, e-beam lines 1-2 μ wide were developed in 3800 Å thick PEMA resist at 1 × 10^?5 C/cm² with ≤200 Å loss in unexposed resist thickness. The higher differential dissolution with CCl₄, a poorer solvent for unirradiated PMMA than acetone or MEK, is explained by decline in polarity of PMMA by radiationinduced decarboxylation.     

Synthesis and characterization of poly(methyl methacrylate‐co‐maleic anhydride) copolymers and its potential as a compatibilizer for amorphous polyamide blends

Poly(methyl methacrylate‐co‐maleic anhydride) copolymers (MMA‐MA) have been synthesized by solution method, using toluene as solvent and benzoyl peroxide as initiator. The MMA‐MA copolymers were characterized by size exclusion chromatography, Fourier transforms infrared spectroscopy (FTIR), and titration. It was found that the modified polymerization procedure used in this work was more effective in controlling the molecular weight when adding different amounts of maleic anhydride (MA) than procedures previously used. In spite of the significant difference in reactivity ratios between MMA and MA, up to 50% of the MA added to the reactor was incorporated into the copolymer. The evidences for reactions of the MA groups of the MMA‐MA copolymer with the amine end groups of the amorphous polyamide (aPA) during melt blending was obtained by rheological measurements. In this work, the molecular weight and the content of MA reactive functional groups in the MMA‐MA copolymer were varied independently and its effects on the interaction with aPA were studied. It was observed that a compromise between molecular weight and the level of reactive functional group of the compatibilizer should be sought to improve the compatibilization of the polymer systems. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

One-step synthesis of methyl isobutyl ketone from acetone and hydrogen over Pd/(Nb2O5/SiO2) catalysts

The surface-phase oxides of niobia on silica substrate ((Nb₂O₅/SiO₂), NS(x)) were prepared and characterized. Such oxides were used as supports for palladium catalysts. The one-step synthesis of methyl isobutyl ketone (MIBK) from acetone and hydrogen in liquid phase was also investigated over Pd/NS(x) catalysts. Experimental results indicate that these catalysts were effective for the formation of MIBK; since little of the parallel by-product of isopropanol (IPA) was formed, these catalysts reached selectivities of 88–92% MIBK and 2–3% IPA at 30–35% conversion. The reactivity of Pd/NS(x) declined obviously with an increase of water content that accumulated in a semi-batch reaction system. The water could be partially expelled and the deactivation of catalysts could be improved by using a fixed bed continuous flow reaction system.