Synthesis Of Ethers Research Articles

Multicriteria optimization of the catalytic reaction for the synthesis of benzyl butyl ether based on the kinetic model

Multicriteria optimization of the catalytic reaction for the synthesis of benzyl butyl ether based on the kinetic model

Development of dimethyl ether synthesis processes using by-product gas from a steel-making plant: Single-vs. two-step processes

This work addresses the development of a DME synthesis process from a mixture of coke oven gas (COG) and FINEX tail gas (FTG) from a steel-making plant. Two different syngas-to-DME processes were considered: one using two separate reactors for the methanol synthesis over Cu–ZnO–Al2O3 (CZA) and the methanol dehydration over ferrierite (FER) zeolite catalysts, and the other using a single reactor by physically mixing the two catalysts. Kinetic models were developed for each catalyst and the kinetic parameters were estimated by fitting the experimental data at various conditions of temperatures, pressures, space velocities, and feed compositions. The process modeling results showed that the single reactor achieved a CO conversion of 88.1% and a DME production rate of 450 kg/h, while the corresponding values for the method employing two separate reactors were 38.6% and 240 kg/h, respectively. This difference is attributable to the spontaneous conversion of the produced MeOH to DME, by the coexistence of the two catalysts, which shifted the equilibrium of MeOH production forward. The comparison between the open-loop and recycled cases showed that the carbon efficiency could be more than doubled for both reactor configurations when the unreacted gas was recycled. Finally, the single-reactor configuration employing the recycled stream produced DME at a rate of 825.9 kg/h with the complete consumption of CO and a CO2 conversion of 76%. This indicated that such a process would maximize the use of by-product gas and increase the economic feasibility of steel-making plants.

Prediction of the epichlorohydrin derived cytotoxic substances from the eluent of poly(glycerol glycidyl ether) films

Glycerol-based epoxy networks have great potential for surface functionalization, providing anti-microbial and protein repellant function. However, the synthesis of glycerol glycidyl ether (GGE) monomer often requires excessive epichlorohydrin (ECH). ECH derived organochloride containing byproducts from monomer production maybe present in the eluent of the polymer networks prepared by cationic ring-opening polymerization. Here, the cytotoxicity analysis revealed cell damages in contact with the polyGGE eluent. The occurrence of organochlorides, which was predicted based on the data from high-performance liquid chromatography/electrospray ionization mass spectrometry, as confirmed by a constant chloride level in GGE and polyGGE, and by a specific peak of C–Cl in infrared spectra of GGE. The resulting polyGGE was densely crosslinked, which possibly contribute to the trapping of organochlorides. These results provide a valuable information for exploring the toxins leaching from polyGGE and propose a feasible strategy for minimizing the cytotoxicity via reducing their crosslink density.Graphic abstractThe eluent of poly(glycerol glycidyl ether) (polyGGE) films impaired the viability and metabolic activity of L-929 cells due to the organochloride byproducts or epichlorohydrin precursors originating from the GGE monomer, which was predicted based on the data from high-performance liquid chromatography/electrospray ionization mass spectrometry (HPLC–ESI–MS) and confirmed by chloride content analysis and attenuated total reflection fourier transform infrared (ATR-FT-IR) spectroscopy.

A new mechanism for pore enlargement in mesoporous materials and its application on biodiesel production

ABSTRACT In the conventional method of synthesis by using cyclohexylamine (CA) as template produces in the pore range of 0–3 nm. To enlarge the pore size which is suitable for biodiesel synthesis, the modified synthesis method is adopted by using CA as a template. In this novel method, pore size is enlarged to 7 nm. Cyclohexylamine was applied as a template for AlPO4 and AlSiO4 molecular sieves synthesis. In AlSiO4 synthesis, tetraethyl orthosilicate hydrolyzed to produce ethyl carbocation which is used for ethylation of CA in the presence of aluminum chloride. This ethylated CA size is large enough to produce a large pore size (7 nm). In AlPO4 two types of pore are produced with a pore size of 3 and 7 nm. The 3 nm are created by CA and 7 nm by the binding of CA with phosphoric acid. The synthesized materials are analyzed by physicochemical characterization. AlPO4 has a neutral framework, but the synthesized AlPO4 has acidity which is evidence for the CA binding with phosphoric acid. The synthesis of a promising catalyst (AlPO4-7 and AlSiO4-7) with an enlarged pore that can be effectively applied for the production of biodiesel from waste cooking oil (WCO) at room temperature. The acidity of the synthesized AlPO4 and AlSiO4 are 0.168 and 0.548 mmol/g. These catalysts are active at room temperature due to higher acidity. So the reaction takes place faster and it will reduce the reaction time. It is observed that AlSiO4 produces 90% biodiesel and AlPO4 produces 72% biodiesel with a shorter reaction time. This result reveals that 7 nm pores are suitable for biodiesel production. The diethyl ether selectivity of AlPO4 and AlSiO4 is 24% and 4%, respectively. This is due to the 3 nm pore size created by CA in AlPO4 and it favors diethyl ether synthesis.

Chemodivergent Synthesis of Oxazoles and Oxime Ethers Initiated by Selective C-N/C-O Formation of Oximes and Diazo Esters.

Chemodivergent reactions of oximes and diazo esters involving Rh-catalyzed [3+2] annulation and photodriven O-H insertion have been developed to generate oxazoles and oxime ethers. A range of aldehyde and ketone oximes reacted with α-diazocarbonyl compounds in a controllable manner in which functional groups, including ketone, ester, amide, ether, thiol ether, silane, alkene, allene, and alkyne groups, were well tolerated.

Zwitterionic Iron(II) Compounds: Synthesis, Reactivity, and Catalytic Carbonylative Polymerization of Cyclic Ethers

Zwitterionic Iron(II) Compounds: Synthesis, Reactivity, and Catalytic Carbonylative Polymerization of Cyclic Ethers

Synthesis and antiprotozoal activity of pyridine thioaryl ethers

By reaction of pyridine nitro derivatives containing a mobile halogen atom with thiols of the benzene series, twelve thioaryl ethers of nitropyridine were obtained. However, 2-chloro-3-nitropyridine and 2-chloro-5-nitropyridine were used as reactive pyridine compounds. The reaction was carried out in dimethylformamide (DMFA) or dimethyl sulfoxide (DMSO) in the presence of bases: sodium ethylate, potash, sodium hydride. Generally, the yields exceeded 90%. The sulfur containing derivatives of aromatic series were 2-mercaptobenzoic acid (compound 1 of Table 1), methyl ester of 2-mercaptobenzoic acid (compounds 2 and 3 of Table 1), compound 3 being obtained by reduction of nitro group of compound 2. Also the amides of 2-mercaptobenzoic acid were used: 3-dimethylaminopropylamide of 2-mercaptobenzoic acid (compound 4 of Table 1), and also the reduction product of compound 4 to 3-aminopyridine derivative (compound 5 of Table 1) and morfolide of 2-mercaptobenzoic acid (compound 6 of Table 1). To make the water-soluble a sodium salt of 2-mercaptobenzoic acid was obtained (compound 7 of Table 1). A number of compounds with the pyridine ring nitrogroup reduced to amine (compounds 8, 10 of Table 1), as well as a number of derivatives containing both free (compounds 9, 10 of Table 1) and acylated amino group (compound 11 of Table 1) were also obtained. We also prepared compound 12 representing a product of interaction of 2-chloro-3-nitropyridine with 2-mercapto-3-acetylpyridine. We should note that the best nitrogroup reductant for the synthesis of compounds 3, 5, 7, and 10 is powdered iron in alcohol medium containing both inorganic and organic acids (hydrochloric or acetic acid). The application of other reducing agents (sodium sulfide and ammonium sulfide) led to strong resinification of the reaction mixture. The compounds were recrystallized from organic solvents (ethyl acetate, benzene, ethanol) for purification. Significant antiprotozoic activity was found in 7 of 12 compounds (58%), with 3-nitro-2-chloropyridine being the most active (7.8 and 3.9 ?g/ml). To enhance the activity, the synthesis of compounds with an amino group in the benzene ring as well as the introduction of both donor and acceptor substituents into the benzene ring is recommended.

CO2 capture and utilization from supercritical coal direct chemical looping combustion power plant – Comprehensive analysis of different case studies

Carbon dioxide utilization has gained much attention as a greenhouse gas (GHG) abatement strategy complementary to carbon dioxide storage. Fossil fuel (including coal) based power plants are the large emitters of carbon dioxide as a single sector. Chemical looping combustion is an inherent CO2 capture technology and can also be used for hydrogen production. The captured CO2 and H2 can be used as reactants for synthesis of various products. Present study explores the carbon dioxide utilization (CDU) from the coal direct chemical looping (CDCL) combustion plant with power and hydrogen co-generation to produce four valuable products as four different cases. These case studies include formic acid (FA), methane, methanol, and dimethyl ether (DME) synthesis plants. The performance of these integrated plants is evaluated based on a comprehensive assessment including energy, exergy, ecological, economic and life cycle (4-E&L) analyses. Levelised cost of the products (LCOP) of CDU plants are estimated and compared. Results of 4-E&L analyses show that the CDCL plant with formic acid synthesis is the most favourable option with 100% CO2 utilization efficiency. At the end, the LCOPs estimated from the proposed CDU integrated CLC based power plant are compared against the LCOPs obtained from two different approaches using hydrogen production from solid oxide electrolysis cell (SOEC). The proposed approach is found to be resulting in less LCOP compared to the other approaches.

Analyses and rates of reactions influenced by water in synthesis of polyoxymethylene dimethyl ethers from trioxane and methylal

Polyoxymethylene dimethyl ethers (PODEn) are promising diesel blend components with high oxygen content, high cetane number and similar properties to diesel. In this paper, we conducted a series of experiments for synthesizing PODEn over a HZSM-5 catalyst in a batch stirred autoclave using methylal and trioxane as reactants. Our research focused on the water influence on these syntheses by contrasting the differences from experiments with or without water and built reaction pathway and rate laws. The experimental and kinetic results showed that decrease of water amount could not only increase yields of the PODEn but also reduce the influences on formation rates of the desired products and eliminate some side reactions. Therefore, it is necessary to optimize water amount in the raw materials for balancing costs of the feed and operation as well as yields of the products to maximize the economy in a commercial production of PODEn.

Modular ketal-linked prodrugs and biomaterials enabled by organocatalytic transisopropenylation of alcohols

Isopropenyl ethers are critical intermediates for accessing medicinally valuable ketal-based prodrugs and biomaterials, but traditional approaches for the synthesis of isopropenyl ethers suffer from poor functional group compatibility and harsh reaction conditions. Here, we develop an organocatalytic transisopropenylation approach to solve these challenges, enabling the synthesis of isopropenyl ethers from various hydroxyl-group-containing small-molecule drugs, polymers, and functional building blocks. The method provides a straightforward and versatile synthesis of isopropenyl ethers, features excellent tolerance of diverse functional groups, applies to a wide range of substrates, and allows scalable synthesis. The development of this organocatalytic transisopropenylation approach enables access to modular preparation of various acid-sensitive ketal-linked prodrugs and functionalized ketalated biomaterials. We expect our syntheses and transformations of isopropenyl ethers will find utility in several diverse fields, including medicinal chemistry, drug delivery, and biomaterials.

An analysis of dimethyl ether synthesis from syngas

The dimethyl ether (DME) is an environmentally friendly fuel, that can replace succesfully the petroleum Diesel in engines, or the LPG fuel. In the last period, the world production of DME was steadily rising, with annual rates of 5-8%. The actual commercial technologies producing DME are based on the methanol etherification (the two-step process). An important research effort was expensed in last decennia, in the development of technologies transforming directly the synthesis gas into DME, without separation of the intermediary methanol (the direct or one-step process). This work presents data related to the direct DME synthesis technologies from synthesis gas, thermodynamic particularities of the chemical process and design issues of multi-tubular fixed bed catalytic reactor for gas phase DME synthesis. It is proposed a new constructive solution of the synthesis reactor, with the reactor divided in multiple zones, having distinct catalyst compositions and cooling characteristics. The simulation calculations evidenced the important increase in DME production that can be achieved by this constructive solution, as consequence of an improved control of process evolution along the catalytic reactor.

Polyether-Based Diblock Terpolymer Micelles with Pendant Anthracene Units-Light-Induced Crosslinking and Limitations Regarding Reversibility.

The synthesis of 9-methylanthracenyl glycidyl ether (AnthGE) as a crosslinkable monomer that can be applied in anionic ring opening polymerization is reported. Diblock terpolymers of the composition methoxy-poly(ethylene oxide)-block-poly(2-ethylhexyl glycidyl ether-co-9-methylanthracenyl glycidyl ether) (mPEO-b-P(EHGE-co-AnthGE) with 10 to 24 wt% of AnthGE are synthesized and characterized. Their micellization behavior, as well as their light-induced core-crosslinking via irradiation with UV light (λ = 365nm) is studied. The results are compared with studies on the dimerization, and the dimer cleavage via irradiation with UV-C light (λ = 254nm), of the same diblock terpolymer in organic solution, and the small-molecule model compound 9-methoxymethylanthracene. Differences in 1 H NMR spectra of the crosslinked or dimerized compounds and reaction kinetics of the dimerization reactions under different conditions suggest possible side reactions for the case of the core-crosslinking of micelles in aqueous solution. These side reactions limit the reversibility of the anthracene dimerization reaction in aqueous solutions, even if the anthracene molecule is encapsulated within the hydrophobic core of a polymeric micelle.

Synthesis of polyfluorinated aromatic ethers and thioethers by synergistic cleavage of C-B bond and C-F bond of B(C6F5)3

A concise and efficient method for the synthesis of polyfluorinated aromatic ethers and thioethers by synergistic cleavage of C-B bond and C-F bond of B(C6F5)3 is reported. The reaction could proceed smoothly with excellent functional-group compatibility. In addition, the transformation represents the first general application of B(C6F5)3 as reaction partners in cross-coupling reaction.

Iodine catalysed synthesis of unsymmetrical benzylic ethers by direct cross-coupling of alcohols

Although symmetrical ethers can be synthesized easily from alcohols, synthesis of unsymmetrical ethers by dehydrative cross-coupling of alcohols is still a challenge. While dehydrative cross-coupling is environmentally appealing due to formation of water as the only byproduct, the chances for formation of symmetrical ethers always exist. The existing transition metal based methods give good selectivity, but the catalyst are costly and not readily available. Here, we present a simple, readily available, and cost-effective catalyst in the form of molecular iodine which catalyzes a highly selective cross-coupling of benzylic alcohols with benzyl, alkyl, and aryl alcohols to give their corresponding unsymmetrical ethers in good to excellent yield.

Role of metal center and coordination environment in M-(Z)-N-((E)-pyridin-2-ylmethylene)isonicotinohydrazonate (M = LaIII, ZnII, CdII or HgII) catalyzed cyanosilylation of aldehydes

A series of known metal complexes, [LaL2(NO3)(H2O)2]·5H2O (1), [Zn(μ-L)(NO3)(H2O)]n (2), {[Cd2(μ-HL)(μ-L)(NO3)3(H2O)]·H2O}n (3) and [Hg(μ-L)(N3)]n·nH2O (4), were synthesized from the corresponding metal salts and 2-pyridinecarboxaldehyde isonicotinoylhydrazone (HL), and demonstrated high activity and selectivity in the cyanosilylation of aldehydes. Although all the complexes are derived from the same HL hydrazone ligand, the catalytic activity of 1–4 is different and relates to the metal center and coordination environment, whereas complex 1 being the most effective homogeneous Lewis acid-base catalyst towards the synthesis of cyanohydrin trimethylsilyl ethers from both aliphatic and aromatic aldehydes with yields up to 96.3 % in 6 h in methanol solution and at room temperature. According to the proposed mechanism, both coordination and noncovalent interactions (hydrogen and tetrel bonds) play a significant role and account for the higher catalytic activity of complex 1.

Effects of water and methanol on synthesis of polyoxymethylene dimethyl ethers from dimethoxymethane and paraformaldehyde

Water and methanol are two unavoidable by-products for synthesis of polyoxymethylene dimethyl ethers (PODEn) from dimethoxymethane (DMM) and paraformaldehyde (PF), but their effects have not been clearly studied. As DMM decomposes with water and is formed with methanol, the decomposition ratio of DMM is a key quantity to describe the effects of water and methanol. Using this quantity, a simple and accurate method was proposed for calculating CH2O conversion and a complete model of Schulz-Flory (SF) distribution was established in the presence of water/methanol, both of which were validated experimentally. Then the effects of water and methanol were investigated in detail. The presence of water and methanol had complicated effects on equilibrium of the reaction, and both significantly decreased the yield of PODE3-5. These results showed that both water and methanol should be removed from the recycling stream in an industrial plant to enhance the efficiency of the reactor.

Oxime Ether Synthesis through O-H Functionalization of Oximes with Diazo Esters under Blue LED Irradiation.

A green and sustainable oxime ether formation method via the visible-light-promoted O-H functionalization of oximes with diazo esters is described. The reaction occurs under very mild conditions (catalyst- and additive-free) with a high yield and a high functional group tolerance. When the reaction was performed with a cyclic ether as the solvent (e.g., THF, 1,4-dioxane, tetrahydropyran, ect.), an interesting photochemical three-component reaction product was obtained in good yields.

Catalytic Reductive Alcohol Etherifications with Carbonyl-Based Compounds or CO2 and Related Transformations for the Synthesis of Ether Derivatives.

Ether derivatives have myriad applications in several areas of chemical industry and academia. Hence, the development of more effective and sustainable protocols for their production is highly desired. Among the different methodologies reported for ether synthesis, catalytic reductive alcohol etherifications with carbonyl‐based moieties (aldehydes/ketones and carboxylic acid derivatives) have emerged in the last years as a potential tool. These processes constitute appealing routes for the selective production of both symmetrical and asymmetrical ethers (including O‐heterocycles) with an increased molecular complexity. Likewise, ester‐to‐ether catalytic reductions and hydrogenative alcohol etherifications with CO2 to dialkoxymethanes and other acetals, albeit in less extent, have undergone important advances, too. In this Review, an update of the recent progresses in the area of catalytic reductive alcohol etherifications using carbonyl‐based compounds and CO2 have been described with a special focus on organic synthetic applications and catalyst design. Complementarily, recent progress made in catalytic acetal/ketal‐to‐ether or ester‐to‐ether reductions and other related transformations have been also summarized.

Effects of Zinc and Aluminum on the CuO Crystalline Size for Direct Dimethyl Ether Synthesis from Syngas

AbstractThe effects of zinc and aluminum on the CuO crystalline size for direct dimethyl ether (DME) synthesis from syngas were investigated. Metal oxide catalysts were synthesized with various molar ratios of CuO by the precipitation method, and by the co‐precipitation method with CuO/ZnO (CZ), CuO/ZnO/Al2O3 (CZA), and CZA at ratios of 1:1, 2:2:1, and 6:3:1, respectively. The acid catalysts (γ‐Al2O3, HZSM‐5) were added to the metal oxide catalysts by physical mixing. The catalysts were characterized morphologically and their acidities were determined. Loading of zinc and aluminum at different ratios showed that CZA (2:2:1) gave the smallest CuO crystalline size, appropriate for the methanol synthesis reaction. γ‐Al2O3 has a weak to moderate acidity range, suitable for DME synthesis. Moreover, the bifunctional catalyst, CZA (2:2:1)/γ‐Al2O3, had the highest surface area as well as the highest %CO conversion and %DME selectivity.

Nucleophilic Vinylic Substitution (SNV) of Trisubstituted Monofluoroalkenes for the Synthesis of Stereodefined Trisubstituted Alkenes and Divinyl Ethers.

We herein describe a nucleophilic vinylic substitution (SNV) of trisubstituted monofluoroalkenes with excellent stereocontrol (d.r. > 99:1). Starting from (E)-β-monofluoroacrylates, various trisubstituted (E)-alkenes containing O/N/S-substituent groups at the vinylic position can be obtained under simple conditions. Furthermore, (E,E)-divinyl ethers can be generated through dimerization of the monofluoroalkenes, triggered by adventitious water in the reaction mixture.