Vapor Phase Carbonylation Research Articles

Vapor-Phase Carbonylation of Methanol with the Obtaining of Acetyls on Solid-Phase Catalysts: A Review

Vapor-Phase Carbonylation of Methanol with the Obtaining of Acetyls on Solid-Phase Catalysts: A Review

A Ni–Fe alloy supported by active carbon efficiently promotes the vapor phase catalytic carbonylation of ethanol

STY (mg g−1 h−1)—space-time yield of propionic acid and ethyl propionate. A Ni–Fe/AC catalyst with high dispersion and a high number of active sites promotes vapor phase carbonylation of ethanol.

Theoretical exploration of the origin of selectivity for the oxidative carbonylation reaction catalyzed by a single Pd atom embedded on graphene

A Pd–COOCH3 species in the vapor-phase carbonylation of methyl nitrite is revealed to have two-fold reactivity, where the nucleophilicity of the Pd–C bond enables C–C coupling to give DMO and the electrophilicity of the π* orbital facilitates C–O coupling to afford DMC.

Effect of microstructure of supports on catalytic activities of carbonylation catalysts

Nickel (Ni)-based catalysts supported by different active carbons (C) were prepared and used for vapor-phase carbonylation of ethanol. The microstructural properties of carbon supports were well investigated by using physical adsorption of nitrogen (N2), X-ray photoelectron spectroscopy, infrared spectrometry, Boehm titration and scanning electron microscopy. The catalytic activities of nickel/carbon catalysts were also studied. The results showed that wood charcoal had a large quantity of mesopores, a larger specific surface area and more oxygen (O)-containing groups such as carbonyl groups. The nickel catalyst supported by wood charcoal showed the highest catalytic activity, with 72.43% of ethanol conversion and 67.46% of product combined selectivity.

Solution-Phase DNA-Compatible Pictet-Spengler Reaction Aided by Machine Learning Building Block Filtering.

SummaryThe application of machine learning toward DNA encoded library (DEL) technology is lacking despite obvious synergy between these two advancing technologies. Herein, a machine learning algorithm has been developed that predicts the conversion rate for the DNA-compatible reaction of a building block with a model DNA-conjugate. We exemplify the value of this technique with a challenging reaction, the Pictet-Spengler, where acidic conditions are normally required to achieve the desired cyclization between tryptophan and aldehydes to provide tryptolines. This is the first demonstration of using a machine learning algorithm to cull potential building blocks prior to their purchase and testing for DNA-encoded library synthesis. Importantly, this allows for a challenging reaction, with an otherwise very low building block pass rate in the test reaction, to still be used in DEL synthesis. Furthermore, because our protocol is solution phase it is directly applicable to standard plate-based DEL synthesis.

Effect of NaOH content in the synthesis gel on the catalytic performance of H-ZSM-5 zeolites in the gas phase carbonylation of dimethoxymethane

AbstractA series of H-ZSM-5 zeolites were prepared by changing the NaOH content in the synthesis gel and their catalytic performance in the vapor-phase carbonylation of dimethoxymethane (DMM) to produce methyl methoxyacetate (MMAc) was investigated. The results indicate that the H-ZSM-5 zeolite prepared with the synthesis gel containing 0.81% NaOH exhibits the highest catalytic activity in the vapor-phase DMM carbonylation. Various characterization results of nitrogen sorption, 27Al NMR, NH3-TPD and Py-FTIR illustrate that both the medium-strong Brønsted acid sites and mesoporous volume are crucial factors in promoting the carbonylation of DMM over H-ZSM-5, which can be effectively regulated by changing the NaOH content in the synthesis gel. The increase of medium-strong Brønsted acid sites can raise the DMM conversion by providing more active acid sites, whereas the mesopores can improve the selectivity to MMAc by shortening the product diffusion path, weakening the steric constraints and suppressing the side reactions. The density functional theory calculation further illustrates that ZOCH2OCH3 intermediate is formed upon the decomposition of DMM on H-ZSM-5; based on this observation, a possible reaction mechanism for the formation of MMAc was then proposed.

Increased Dispersion of Nickel Particles Supported on Activated Carbon by Treating with Methyl Iodide

A novel method dispersing nickel in fine particles on activated carbon (AC) was proposed in this study. The nickel particles with 2.2 nm average diameter supported on AC were obtained through re-dispersing the nickel particles by treating with methyl iodide under atmospheric pressure. High dispersion of nickel particles promoted the activity for methanol vapor-phase carbonylation over Ni/AC catalyst.

Carbonylation of methanol to methyl acetate over Cu/TiO2-SiO2 catalysts: Influence of copper precursors

In the present study, three kinds of copper/titania-silica mixed oxides (Cu/TS) catalysts were prepared using copper chloride, copper nitrate, and copper acetate as copper precursors by the sol-gel method. The catalytic performance was tested in the vapor phase carbonylation of methanol free of halide. The characterization results showed that the interaction between copper and support was the strongest on the 10Cu/TS (Cl) catalyst, leading to the highest copper dispersion and the most surface Cu+ species. As a result, the 10Cu/TS (Cl) catalyst obtained the largest absorption capacity of CO and the maximum amount of Lewis acid sites. The catalytic performance results showed that the space time yield (STY) of methyl acetate (MA) was positively correlated with the content of surface Cu+ species and the specific surface area of the Cu+ cations (SCu(I)). Therefore, the 10Cu/TS (Cl) catalyst obtained the highest STYMA of 1.619 mol/h.kgcat. Moreover, the STYMA per Cu+ site was inversely proportional to the copper particle size, indicating that the carbonylation of methanol to MA is a structure-sensitive reaction. And the methanol conversion was positively correlated with the amount of surface acid sites. Furthermore, the active sites for the synthesis of methyl formate and dimethyl ether were also studied.

Effect of mass-transfer control on HY zeolites for dimethoxymethane carbonylation to methyl methoxyacetate

A series of hierarchical HY zeolites were prepared by using sequential acid (H4EDTA) and alkaline (NaOH and NH4OH) solution treatments. The nitrogen adsorption-desorption analysis proved that the mesoporous structure was definitely formed with the pore diameter at about 3.5 and 17.5 nm, and the external surface area and mesopore volume significantly increased. The XRD, XRF, and NH3-TPD characterization results disclosed that the relative crystallinity, crystalline sizes, and acidity of as-treated HY zeolites decreased as compared with parent HY although their Si/Al ratios were higher. The zeolites were conducted in vapor phase carbonylation of dimethoxymethane (DMM) to methoxyacetate (MMAc) at 5.0 MPa and different temperatures. As compared with reference HY, the DMM conversion and MMAc selectivity obviously increased from 50.41% to 90.91% and from 34.79% to 84.57% at 383 K, respectively. The DMM conversion were closely related to the medium-strong acid amount and greater amount of medium-strong acid sites resulted in higher DMM conversion. The catalytic stability of HY-DAl0.11-DSiNaOH0.05 was carried out at 393 K and 5.0 MPa for 100 h. The DMM conversion (about 97%) and products selectivity (MMAc: 84%) kept unchanged during the whole carbonylation process, exhibiting excellent catalytic stability, which was also supported by the TG-DTA analysis that the carbon deposition was effectively suppressed. In a word, as-treated HY zeolites with larger external surface area and mesopore volume that contributed to promoting the mass transfer efficiency exhibited much higher DMM conversion, MMAc selectivity and excellent catalytic stability than parent HY.

A highly efficient sulfonic acid resin for liquid-phase carbonylation of dimethoxymethane

The influence of H2O content on DMM carbonylation using a DICP-001 resin catalyst (Fig. 6).

Enhancement of the catalytic performance in Pd-Cu/NaY catalyst for carbonylation of methyl nitrite to dimethyl carbonate: Effects of copper doping

Doping copper in Pd/NaY catalyst has been developed for vapor-phase carbonylation of methyl nitrite (MN) to dimethyl carbonate (DMC). Different characterization methods were employed to investigate the role of Cu in the catalyst. The introduction of Cu2+ could effectively promote the dispersion of Pd species by shrinking the size of Pd species NPs, while the oxidation state of Pd could be maintained simultaneously for better selectivity. Furthermore, the strength of Pd-CO can be tuned by the amount of Cu, which is the most crucial problem towards the reaction cycle.

Effect of Cerium Dioxide in NiCl2–CuCl2 Compositions Deposited on Activated Carbon on Their Catalytic Properties in the Vapor-Phase Carbonylation of Methanol

It was shown that modification of the catalytic composition NiCl2–CuCl2 with cerium dioxide on activated carbon leads to increase in the selectivity of formation (87%) and yield (38%) of methyl acetate in the vapor-phase carbonylation of methanol. The promoting effect is caused by increase in the dispersion of the deposited particles of copper and nickel chlorides and also by the possible formation of mixed (Cu–Ce)-containing phases that are more selective with respect to methyl acetate production.

Vapor phase ethanol carbonylation over Rh supported on zeolite 13X

While methanol carbonylation has been extensively studied, higher alcohol carbonylation has received relatively little attention, even though, for example, ethanol carbonylation could be a useful route for the production of propionates. Here we use Rh/Na13X to investigate the vapor phase carbonylation of ethanol with an ethyl iodide co-feed. In the base case, the catalyst is ∼40% selective to propionates, with the remainder forming ethylene and diethyl ether. Deposition of additional alkali can increase selectivities to ∼60%. Isotopic labeling of ethyl iodide demonstrates reversible formation of ethyl iodide from ethanol, and that preferential incorporation of ethyl iodide initiates the Rh-catalyzed carbonylation cycle. XPS and in situ X-ray absorption spectroscopy are consistent an active anionic RhI iodide species at a zeolite exchange site. This proposed structure and the attendant catalytic reaction network are directly analogous to those of classic solution-phase Rh catalysts and other supported Rh catalysts. However, important differences are noted in the reaction orders and apparent activation barrier, which suggest that the rate of ethyl iodide formation is overall rate limiting under these conditions and for this catalyst.

Study on the influence of oxygen-containing groups on the performance of Ni/AC catalysts in methanol vapor-phase carbonylation

The activated carbon was pretreated by different concentrations of HNO3 solution to prepare Ni/AC catalysts with different oxygen contents. The change of the oxygen-containing groups during the carbonylation was traced using an instrument named Micro-Fluidized Bed Reactor Analyst-Particle (MFBRA-P), which can sample out catalyst particles on-line at specific time interval during the reaction. The on-line sampled catalysts were characterized by N2-sorption, inductively coupled plasma-atomic emission spectroscopy (ICP-AES), transmission electron microscope (TEM), temperature programmed desorption (TPD), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). It was found that catalysts with smaller amount of oxygen-containing groups had higher initial activity and higher deactivation rate, which was consistent with the accumulation rate of oxygen-containing groups. High content of oxygen suppressed the accumulation of oxygen-containing carbonaceous deposits, resulting in better catalytic stability for carbonylation.

Activity enhancement of Nafion resin: Vapor-phase carbonylation of dimethoxymethane over Nafion-silica composite

A kind of composite materials consisting of nano-sized Nafion resin homogeneously dispersed in a high-surface silica matrix was prepared by sol–gel method and used as catalysts in the vapor-phase carbonylation reaction of dimethoxymethane for production of methylmethoxy acetate. These composite catalysts showed much higher catalytic activity in comparison with the original pure Nafion resin catalyst. The remarkable improvement of catalytic performance was due to the increased accessibility of acid sites of Nafion resin in the composite catalysts. The contents of Nafion-H resin and silica precursors were found to have a great influence on the structure of the composite, resulting in different catalytic activity during DMM carbonylation reactions. Furthermore, the comparison of the composite catalysts with high-silica H-Y and H-Beta zeolite catalysts demonstrated that the excellent catalytic performance is closely related to the higher acid strength and larger pores of Nafion-silica composite materials.

(Pd–CuCl2)/γ-Al2O3: a high-performance catalyst for carbonylation of methyl nitrite to dimethyl carbonate

(Pd–CuCl2)/γ-Al2O3 catalyst with excellent activity and selectivity was successfully developed for vapor-phase carbonylation of methyl nitrite to dimethyl carbonate (DMC).

A highly efficient Nafion-H catalyst for vapour phase carbonylation of dimethoxymethane

Nafion-H resin catalyst exhibits a remarkably high activity and selectivity for methyl methoxyacetate in the vapor phase carbonylation of dimethoxymethane.

Synthesis of Dimethyl Carbonate through Vapor‐Phase Carbonylation Catalyzed by Pd‐Doped Zeolites: Interaction of Lewis Acidic Sites and Pd Species

All doped up: The interaction between Lewis (L) acidic sites and Pd species in the vapor-phase carbonylation reaction of methyl nitrite over Pd/Faujasite (FAU) catalysts is determined quantitatively. By keeping the Pd species in an electron-deficient state, the Lewis acids of the Pd/FAU catalysts promote the synthesis of dialkyl carbonates.

Activated Metallic Gold as an Agent for Direct Methoxycarbonylation

We have discovered that metallic gold is a highly effective vehicle for the low-temperature vapor-phase carbonylation of methanol by insertion of CO into the O-H bond to form methoxycarbonyl. This reaction contrasts sharply to the carbonylation pathway well known for homogeneously catalyzed carbonylation reactions, such as the synthesis of acetic acid. The methoxycarbonyl intermediate can be further employed in a variety of methoxycarbonylation reactions, without the use or production of toxic chemicals. More generally we observe facile, selective methoxycarbonylation of alkyl and aryl alcohols and secondary amines on metallic gold well below room temperature. A specific example is the synthesis of dimethyl carbonate, which has extensive use in organic synthesis. This work establishes a unique framework for using oxygen-activated metallic gold as a catalyst for energy-efficient, environmentally benign production of key synthetic chemical agents.

ChemInform Abstract: Vapor Phase Carbonylation of Organic Halo Compounds.

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