Methyl Phenyl Carbonate Research Articles

Preparation and catalytic property of modified multi-walled carbon nanotube-supported TiO2 for the transesterification of dimethyl carbonate with phenol

Modified multi-walled carbon nanotube-supported TiO2 samples were prepared and used as an efficient heterogeneous catalyst for the transesterification of dimethyl carbonate with phenol. The catalysts were characterized by X-ray photoelectron spectroscopy, transmission electron microscopy, N2 adsorption-desorption, and X-ray powder diffraction. The results showed that the catalyst, which was prepared using a low concentration (0.4%) of ammonium hydroxide as the precipitant instead of ionized water, had better catalytic activity, separability, and reusability properties. The effects of the TiO2 loading, amount of catalyst and reaction time on the performance of the transesterification reaction were also studied. Under the optimum reaction conditions, the conversion of phenol reached 42.5% with over 99.9% selectivity for methyl phenyl carbonate and diphenyl carbonate. The catalyst could be reused for the transesterification in four runs with only slight loss of its catalytic activity.

Cerium‐Based Binary and Ternary Oxides in the Transesterification of Dimethylcarbonate with Phenol

Diphenyl carbonate (DPC) plays a key role in phosgene-free carbonylation processes. It can be produced by transesterification of dimethyl carbonate (DMC) with phenol in the presence of catalysts. Methyl phenyl carbonate (MPC) is first produced that is then converted into DPC by either disproportionation or further transesterification with phenol. Cerium-based bimetallic oxides (with the heterometal being niobium, iron, palladium, or aluminum) are used as catalysts in the transesterification of DMC to synthesize MPC. The catalytic activity is affected by the type and concentration of the heterometal. XPS, IR and elementary analyses are employed to characterize the new catalysts. Differently from pure oxides, the mixed oxides produce a significant increase of the conversion and selectivity towards MPC.

Liquid–Liquid Equilibria for Ternary Mixtures of Methylphenyl Carbonate, Dimethyl Carbonate, Diphenyl Carbonate, Anisole, Methanol, Phenol, and Water at Several Temperatures

The ternary liquid–liquid equilibria (LLE) at atmospheric pressure of the following systems have been studied at several temperatures in stirred, thermo-regulated cells: water + anisole + methyl phenyl carbonate (MPC) at 308.15 K, water + methanol + MPC at 308.15 K, water + dimethyl carbonate (DMC) + MPC at 308.15 K, water + phenol + MPC at 318.15 K, and water + diphenyl carbonate (DPC) + MPC at 358.15 K. The experimental ternary LLE data have been satisfactorily correlated with the well-known two activity coefficient models: the Non-Random Two-Liquid (NRTL) and UNIversal QUAsiChemical (UNIQUAC). In addition, the distribution coefficients and the selectivity values of MPC for anisole, methanol, DMC, phenol, and DPC were derived from the tie-line data.

ChemInform Abstract: Methyl Formate as a Carbonylating Agent for the Catalytic Conversion of Phenol to Methyl Phenyl Carbonate.

AbstractA new protocol for the formation of methyl phenyl carbonate by oxidative carbonylation of phenol with methyl formate is developed, which does not require the use of toxic CO gas.

Methyl formate as a carbonylating agent for the catalytic conversion of phenol to methyl phenyl carbonate

Methyl formate was used as a green and efficient carbonylating agent in the synthesis of methyl phenyl carbonate from phenol. Methyl formate showed better performance compared to toxic CO gas and the ability to produce other useful carbonylated products, e.g., dimethyl carbonate and dimethyl oxalate.

A green metrics assessment of phosgene and phosgene-free syntheses of industrially important commodity chemicals

Synthesis plans for the following important industrial commodity chemicals using phosgene and phosgene-free chemistries have been analyzed and compared by green metrics to determine the most material-efficient routes so far developed (number of plans given in parentheses): dimethyl carbonate (DMC) (31), diphenyl carbonate (DPC) (40), diphenylurea (DPU) (23), methyl carbamate (MC) (8), methyl chloroformate (MCF) (6), methyl N-phenylcarbamate (MNPC) (25), methyl phenyl carbonate (MPC) (32), phenyl isocyanate (PI) (19), phenyl chloroformate (PCF) (10), and urea (13). Implications of these results are discussed.

Synthesis and Characterization of Polyhydroxyurethanes Prepared from Difunctional Six-Membered Ring Carbonates

New polyhydroxyurethanes (PHUs) were prepared from (5-ethyl-2-oxo-1,3-dioxan-5-yl)methyl phenyl carbonate and (5-ethyl-2-oxo-1,3-dioxan-5-yl)methyl imidazolyl carbonate with ethylenediamine, tetramethylenediamine and hexamethylenediamine. These PHUs were characterized by SEC, DSC, TGA, NMR spectroscopy and IR spectroscopy, and the results were compared to previously reported results of PHUs prepared from phenoxycarbonyl-oxymethyl ethylene carbonate with corresponding diamines.

Transesterification of dimethyl carbonate with phenol using Brønsted and Lewis acidic ionic liquids

Transesterification reaction of dimethyl carbonate with phenol to methylphenyl carbonate and diphenyl carbonate using dibutyltin oxide catalyst in conjunction with Brønsted and Lewis acidic ionic liquids was studied. It was observed that the use of ionic liquids significantly enhances the yield of diphenyl carbonate. The ionic liquid having p-toluenesulfonate as anion and metal halide (e.g. ZnCl2) as Lewis acid precursor exhibited higher activity and selectivity for diphenyl carbonate formation. Furthermore, the Brønsted and Lewis acidity of ionic liquids was measured by IR spectroscopy using pyridine as a probe and their Lewis acidity order was also determined.

Pyroaurite as an active, reusable and environmentally benign catalyst in synthesis of diphenyl carbonate by transesterification

Abstract The pyroaurite catalyzed synthesis of diphenyl carbonate (DPC) by transesterification of dimethyl carbonate (DMC) and phenol was investigated. Under the optimal reaction condition, the conversion of DMC reached 61.5%, and the yields of DPC and methyl phenyl carbonate were 13.9% and 43.7%, respectively. The catalyst can be recycled and reused several times without significant loss of catalytic activity within the scope of this study.

Reaction from Dimethyl Carbonate to Diphenyl Carbonate. 1. Experimental Determination of the Chemical Equilibria

New experimental equilibrium data of the reaction of dimethyl carbonate (DMC) and phenol to methyl phenyl carbonate (MPC) and the subsequent disproportion and transesterification reaction of MPC to diphenyl carbonate (DPC) are presented and interpreted in terms of the reaction equilibrium coefficients. Experiments have been carried out in the temperature range between 160 and 200 °C and for initial reactant ratios of DMC/phenol from 0.25 to 3. By employing activities instead of “only” mole fractions in the calculation of the reaction equilibrium coefficients, the influence on the reactant ratio DMC/phenol on the derived equilibrium values for the reaction of DMC to MPC could be reduced, especially for temperatures of 160 °C. The activity based equilibrium coefficient for the transesterification reaction from MPC with phenol to DPC and methanol is constant within experimental uncertainty and, therefore, largely independent of the initial reactant ratio DMC/phenol at temperatures of 160 and 180 °C. The temperature dependence of the equilibrium coefficients Ka,1 and Ka,2 has been fitted by applying the well-known Van’t Hoff equation, resulting in the expressions ln Ka,1 = −2702/T[K] + 0.175 and ln Ka,2 = −2331/T[K] − 2.59. It has been demonstrated that these equations have fair, in the case of ln Ka,1, and excellent, in the case of ln Ka,2, predictive capabilities, even for experimental conditions that deviate significantly from those used in this study. Hence, it is expected that the derived temperature dependent correlations for Ka,1 and Ka,2 based on activities can be used in reactive distillation models to assess different process configurations in the manufacture of DPC starting from DMC and phenol.

Reaction from Dimethyl Carbonate (DMC) to Diphenyl Carbonate (DPC). 2. Kinetics of the Reactions from DMC via Methyl Phenyl Carbonate to DPC

The kinetics of the reaction of dimethyl carbonate (DMC) and phenol to methyl phenyl carbonate (MPC) and the subsequent disproportion and transesterification reaction of methyl phenyl carbonate (MPC) to diphenyl carbonate (DPC) have been studied. Experiments were carried out in a closed batch reactor in the temperature range from 160 to 200 °C for initial reactant ratios of DMC/phenol from 0.25 to 3 and varying catalyst (titanium-(n-butoxide)) concentrations. The concept of a closed, ideally stirred, isothermal batch reactor incorporating an activity based reaction rate model has been used to fit kinetic parameters to the experimental data taking into account the catalyst concentration, the initial reactant ratio DMC/phenol and the temperature.

Flammability properties analysis of methylphenol-carbonate in diphenylcarbonate production process

Diphenylcarbonate (DPC) has been regarded as a potential substitute material for highly toxic phosgene, reacting with bisphenol A (BPA) in a phosgene-free process to produce polycarbonate (PC). For synthesizing DPC, methylphenylcarbonate (MPC) was the critical intermediate with potential flammability in a transesterification reaction from dimethylcarbonate (DMC) and phenol. Under the National Fire Protection Association (NFPA) criterion, MPC is viewed as one sort of combustible liquid (Class IIIB). Once it fires or burns during storage, operation or transportation, it can cause a serious fire and explosion. However, researches are still scanty in mentioning the basic but crucial fire and explosion features of MPC to date. A sound background of material safety properties is essential for safe handling; in particular, flammability information is extremely crucial for a specific chemical during a unit operation to prevent any fire and explosion hazards. In this study, we investigated the explosion limits (LEL, UEL), maximum explosion pressure (Pmax), maximum rate of explosion pressure rise ((dP/dt)max), and gas or vapor explosion constant (Kg) of MPC, according to its practical operating conditions (1 atm, 250°C, 21 vol.% O2) and by means of a 20 L vessel (20-L-Apparatus).

The synthesis of diphenyl carbonate from dimethyl carbonate and phenol over mesoporous MoO 3/SiMCM-41

The mesoporous catalyst activities of supported molybdenum oxide for diphenyl carbonate (DPC) synthesis in liquid-phase transesterification of dimethyl carbonate (DMC) and phenol were investigated. The yields of DPC and methyl phenyl carbonate (MPC) were greatly improved when MoO 3 was supported on SiMCM-41 to act as catalyst. MoO 3/SiMCM-41 catalysts were characterized by X-ray diffraction (XRD), N 2 adsorption–desorption isotherms, and Fourier transform infrared (FT-IR) spectroscopy. Characterized results revealed that the high activity sites of MoO 3/SiMCM-41 were isolated MoO 4 2− tetrahedral species and polymerized octahedral molybdenum oxide species. MPC formation increased with reaction time up to 4 h and then decreased thereafter, and maximum MPC yield achieved 39.6%. The decrease of MPC yield after 4 h might be ascribed to MPC disproportionation into DPC and reversible transesterification reaction.

Transesterification of Dimethylcarbonate and Phenol Over Silica Supported TiO2 and Ti-MCM 41 Catalysts: Structure Insensitivity

Silica-supported titanium dioxide (TiO2/SiO2) and Ti-MCM 41 catalysts have been used for transesterification of dimethylcarbonate (DMC) and phenol to methylphenylcarbonate (MPC). The structure and the chemical state of titanium species in TiO2/SiO2 and Ti-MCM 41 have been investigated by means of X-ray diffraction (XRD), X-ray absorption near edge structure (XANES) for Ti K-edge and X-ray photoelectron spectroscopy (XPS). To understand the role of pore size on the activity of catalysts, different pore size silica supports (Q-series) were utilized in TiO2/SiO2 catalysts. Similarly, to understand the effect of Ti symmetry on the activity of catalysts, Ti-MCM 41 was used with different Ti-loadings. It was observed that the Ti surface area was an only important factor to achieve highest activity. In case of Ti-MCM 41 catalysts, as the Ti-loading increased octahedral symmetry increased and tetrahedral symmetry decreased. But, turnover rates based on the surface Ti atoms were independent of the Ti symmetry. They are also similar to those obtained for TiO2/SiO2 catalysts. Showing that transesterification of DMC and phenol over Ti-based catalysts is a structure insensitive reaction.

Transesterification of dimethyl carbonate with phenol to diphenyl carbonate over V 2O 5 catalyst

A novel heterogeneous catalyst, pure V 2O 5 catalyst prepared by calcination of NH 4VO 3 at 550 °C in air, was used for the synthesis of diphenyl carbonate (DPC) by the transesterification of dimethyl carbonate (DMC) with phenol. The effects of V 2O 5 amount, reaction time and molar ratio of dimethyl carbonate to phenol were investigated. Under the conditions of mass fraction of catalyst 1.6%, molar ratio of DMC/phenol of 1.5:1 and a reaction time 9 h, the maximum conversion of phenol and total yields of methyl phenyl carbonate (MPC) and DPC were 42.0 and 40.1%, respectively. Reuse of the catalysts revealed an appreciable deactivation. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform-infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM) characteristics of the fresh and used catalyst samples had been recorded. The results showed that the deactivation of the catalyst was mainly ascribed to the conversion of crystal structure. Moreover, the deactivated catalyst could be easily reactivated by calcination in air, and the regenerated catalyst showed the catalytic activity almost as high as that of the fresh sample. However, a small difference in catalytic activities between regenerated and fresh catalysts was possibly owing to the sintering of the regenerated catalyst.

The transesterification of dimethyl carbonate and phenol catalyzed by 12-molybdophosphoric salts

Various 12-molybdophosphoric salts were used in the transesterification of dimethyl carbonate (DMC) and phenol to diphenyl carbonate (DPC) and methyl phenyl carbonate (MPC) as novel solid catalysts. The zinc salt was found to exhibit the highest activity for the transesterification. Several parameters affecting the transesterification were investigated. When the reaction was performed between 150 °C and 180 °C, with a molar ratio of phenol to DMC of 1, a reaction time 12 h, a catalyst amount 0.004 (molar ratio to phenol), the conversion of phenol reached 31%, and the selectivity of MPC and DPC was 29% and 66.1%, respectively. The TON reached 74.8 mol (MPC + DPC)/mol Zn-salt.

Molybdosphoric Acid Mixed with Titania Used as a Catalyst to Synthesize Diphenyl Carbonate via Transesterification of Dimethyl Carbonate and Phenol

The 12-molybdosphoric acid mixed with titania (MPA-TiO 2) was found to be a novel and efficient catalyst for the synthesis of diphenyl carbonate (DPC) via transesterification of dimethyl carbonate (DMC) and phenol. The X-ray diffraction (XRD) and infrared (IR) techniques were employed to characterize the prepared catalysts. The effect of the weight ratio of the 12-molybdosphoric acid to titania on the transesterification was investigated. A 13.1% yield of DPC and an 11.6% yield of methyl phenyl carbonate (MPC) were obtained over MPA-TiO 22 with the weight ratio of MPA to TiO 2 as 5:1.

Formal Asymmetric Synthesis of a 7-Methoxyaziridinomitosene

The conversion of (-)-2,3-O-isopropylidene-d-erythronolactone (14) and 2-benzyloxy-6-bromo-4-methoxy-3-methyl­aniline (18) into {(1R,2R)-(-)-1-azido-2,3,5,8-tetrahydro-7-methoxy-6-methyl-2-methanesulfonyloxy-5,8-dioxo-1H-pyrrolo-[1,2-a]indol-9-yl}methyl phenyl carbonate (39) has been accomplished in 17 steps by way of the enaminone 26. Key steps included the preparation of 26 by a Reformatsky reaction on a thiolactam precursor 25, and intramolecular Heck reaction of 26 to form the indole ring. The preparation of 39 constitutes a formal synthesis of the fully functionalised 7-methoxyaziridinomitosene 12, only the second such synthesis to have been accomplished.

Transesterification of dimethyl carbonate and phenol to diphenyl carbonate catalyzed by titanocene complexes

Some titanocene complexes were used as catalysts for the transesterification of phenol and dimethyl carbonate to diphenyl carbonate. It was found that titanocene catalysts modified by various substituents would strongly influence the steric and electronic properties of the catalytic centers, the stability of the transition states and their catalytic behaviors. The yields of methyl phenyl carbonate and diphenyl carbonate might be improved by designing the structure of the titanocene complexes. When the substituent was smaller and more electron withdrawing, or the substituent could make the transition state stabler, the reaction would go on with better results.

Ammonium‐Functionalized Polydimethylsiloxanes: Synthesis and Properties

AbstractSummary: Polydimethylsiloxane with trimethylammonium end groups and polydimethylsiloxane with diethylmethylammonium groups in the main chain was prepared by two routes. A novel carbonate coupler – (2‐oxo‐1,3‐dioxolan‐4‐yl) methyl phenyl carbonate – and the amine compounds α,ω‐(3‐aminopropyl) polydimethylsiloxane, 3‐(dimethylamino)‐1‐propylamine, and bis(2‐amino ethyl)amine served as the starting materials. The polymers obtained are hydrophobic and contain ammonium groups suitable for interaction with negatively charged surfaces. Thus these materials can be used for special surface modifications. Thin films were prepared by spin‐coating. Their morphology and properties were determined by means of optical microscopy, SFM, and contact angle measurements. The particle size distribution in aqueous solution of the vesicles formed was determined by means of a laser scattering technique; the particle sizes determined correspond to those obtained by optical microscopy. Finally, the antibacterial effects of these polymers with hydrophobic and cationic groups were tested.α,ω‐Diammonium octadimethylsiloxane molecule (6), an SFM phase image for a spin‐coated film of 6 on a silicon wafer, and a scheme of the way the molecules stack on the surface.magnified imageα,ω‐Diammonium octadimethylsiloxane molecule (6), an SFM phase image for a spin‐coated film of 6 on a silicon wafer, and a scheme of the way the molecules stack on the surface.