Reaction Of Ethylene Oxide Research Articles

Development of 2,2′-Iminodiethanol Selective Production Process Using Shape-Selective Pentasil-Type Zeolite Catalyst

Abstract Ethanolamines are produced on an industrial scale exclusively by the reaction of ethylene oxide with an aqueous solution of ammonia. The reaction is a typical consecutive reaction with three steps; therefore, it is difficult to produce 2,2′-iminodiethanol (the second product of the reaction) with high selectivity by conventional means. We developed a catalytic 2,2′-iminodiethanol selective production process using a pentasil-type zeolite catalyst modified with rare earth elements. This highly active catalyst was able to recognize the difference at molecular level between 2,2′-iminodiethanol and 2,2′,2″-nitrilotriethanol; 2,2′,2″-nitrilotriethanol was not formed in its micropore. We also succeeded in producing a binderless molded zeolite catalyst that does not form problematic impurities and that has a shape suitable for a fixed-bed reactor. The problem of activity deterioration was overcome by developing a regeneration process using high-temperature and high-density ammonia gas as a rinse medium.

Oxidation of ethylene by a multistage corona discharge system in the absence and presence of Pt/TiO2

Abstract The main objective of this work was to investigate a combined plasma and catalytic reactor system for ethylene removal. A four-stage plasma system with wire and plate electrodes was employed to oxidize ethylene as a model pollutant under excess oxygen conditions. The effects of commercial TiO 2 , sol–gel TiO 2 , and 1% Pt/sol–gel TiO 2 loaded on glass wool used as catalysts packed in the plasma reactors were studied. For the plasma system without a catalyst, both the ethylene conversion and the CO 2 selectivity were found to increase with increasing applied voltage and the stage number of the plasma system; but increasing the frequency and feed flow rate gave the opposite effects. The presence of all studied catalysts in the plasma system was found to increase both C 2 H 4 and O 2 conversions. The CO 2 selectivity increased under the presence of the catalysts in the following order: 1% Pt/sol–gel TiO 2 > sol–gel TiO 2 = commercial TiO 2 . When the TiO 2 was present in the plasma reactor system, it enhanced the ethylene oxidation reaction because its reducible property provides both the reaction sites and oxygen for the reaction. The presence of 1% Pt on the sol–gel TiO 2 was found experimentally to promote the CO oxidation, leading to a higher CO 2 selectivity.

Catalytic activity of ethylene oxidation over Au, Ag and Au–Ag catalysts: Support effect

Au, Ag and Au–Ag catalysts on different supports of alumina, titania and ceria were studied for their catalytic activity of ethylene oxidation reactions. An addition of an appropriate amount of Au on Ag/Al 2O 3 catalyst was found to enhance the catalytic activity of the ethylene epoxidation reaction because Au acts as a diluting agent on the Ag surface creating new single silver sites which favor molecular oxygen adsorption. The Ag catalysts on both titania and ceria supports exhibited very poor catalytic activity toward the epoxidation reaction of ethylene, so pure Au catalysts on these two supports were investigated. The Au/TiO 2 catalysts provided the highest selectivity of ethylene oxide with relatively low ethylene conversion whereas, the Au/CeO 2 catalysts was shown to favor the total oxidation reaction over the epoxidation reaction at very low temperatures. In comparisons among the studied catalysts, the bimetallic Au–Ag/Al 2O 3 catalyst is the best candidate for the ethylene epoxidation. The catalytic activity of the gold catalysts was found to depend on the support material and catalyst preparation method which govern the Au particle size and the interaction between the Au particles and the support.

Carboxylation of Styrene Oxide Catalyzed by Quaternary Onium Salts under Solvent-free Conditions

Green chemistry has attracted much attention in organic chemistry. Major goal in this area is to maximize the efficient use of raw materials and simultaneously to minimize waste. In this context, conversion of conventional organic processes into the highly atom-efficient protocol with good selectivity is the most desirable. The carboxylation of epoxides shows an interesting application in the utilization of carbon dioxide to produce cyclic carbonates. These compounds are useful as monomers, polar aprotic solvents, and intermediates for the synthesis of pharmaceuticals and fine chemicals. Recently, we have studied the coupling of CO2 with styrene oxide as a model reaction as the carboxylation of epoxides and have noticed the processes using quaternary onium salts such as tetraalkylammonium and phosphonium halides are of full-atom-economy-type to convert styrene oxide into styrene carbonate: efficient, clean and by-productfree under solvent-free reaction conditions. We found the detailed information on the use of onium salts for this reaction under solvent-free conditions is surprisingly limited except a few examples. The patent by McMullen et al. described the coupling reaction of ethylene oxide with CO2 to produce ethylene carbonate in up to 99% yield when catalyzed by several ammonium salts such as tetraethylammonium chloride and a few other ammonium halides. However, the detailed studies of the reaction profile and the catalytic efficiency of quaternary salts in the coupling of CO2 with epoxides are still lacking so far. Historically, quaternary ammonium halides have been often used as complexed with transition metal catalysts or as the reaction ionic medium to promote the reactions of the coupling of CO2 with epoxides rather than used alone. Recent mechanistic studies suggest on the role of these catalytic systems that an epoxide is coordinated to the halogenated metal anion, generated from the interaction of the metal halide with the halide ion, and the resulting coordinated epoxide ring is opened by the halide ion to form an haloalkoxy species. Nucleophilic attack of the haloalkoxy species on CO2 leads to a linear halocarbonate that is transformed into a cyclic carbonate by the intramolecular substitution of the halide. Herein, we report on the detailed reaction profile of carboxylation of styrene oxide catalyzed by various onium salts, particularly such as quartenary ammonium and phosphonium halides under various temperatures and CO2 pressures as shown in Scheme 1. Quatenary ammonium salts-catalyzed reaction. Table 1 shows the results of the experiments performed to optimize the conditions for the carboxylation of styrene oxide in the Scheme 1

Decomposition of ethylene carbonate in the presence of ionic liquid-based zinc tetrahalide catalysts

A series of ionic liquid-based zinc tetrahalide complexes were synthesized and their effects in the coupling reactions of ethylene oxide (EO) and carbon dioxide to produce ethylene carbonate (EC) were evaluated. The zinc tetrahalide complexes displayed high catalytic activities for the coupling reaction, but were found to cause a severe decomposition of EC during the vacuum-distillation of the product mixture. Among the various factors affecting the EC decomposition, the concentration of zinc tetrahalide species was most responsible for the decomposition: the lower the concentration, the lesser the decomposition. The addition of an imidazolium or ammonium halide was effective for enhancing the activity of the zinc tetrahalide complex while having only a minor effect on the decomposition rate. The optimum catalyst composition was discussed for producing EC feasibly with minimized product decomposition.

Phosphine-bound zinc halide complexes for the coupling reaction of ethylene oxide and carbon dioxide

Phosphine adducts of zinc(II) halides, ZnX 2L 2 (X = Cl, Br, I; L = PMe 2Ph, PEt 3, PBu 3, PPh 3, PCy 3), prepared by the reaction of ZnX 2 with two equivalents of corresponding phosphines, showed high activities for the coupling reaction of CO 2 and ethylene oxide to produce ethylene carbonate. The catalytic activity of ZnX 2L 2 was hardly affected by the nucleophilicity of the phosphine ligands, with the exception of ZnX 2(PCy 3) 2, but depended strongly on the nature of halide ligands. An active species containing ethoxyphosphonium ligands, Zn 3Br 6[ μ-OCH 2CH 2-P(C 6H 5) 3] 3, was isolated and characterized by X-ray crystallography, elemental analysis, and NMR spectroscopy. The mechanistic pathway for the formation of active species and cyclic carbonates is discussed.

Produção de etilenoglicóis e derivados por reações catalíticas do óxido de eteno

Products resulting from the ethoxylation of hydroxylated compounds, especially water and ethanol, are of great commercial importance. This work presents several aspects concerning the catalytic reactions of ethylene oxide, a chemical substance used in the production of a wide variety of products. Mechanisms of ethoxylation, distribution of products, formation of undesired by-products and perspectives for new processes using heterogeneous catalysis are also reviewed and discussed.

Electrochemical Promotion of Ethylene Oxidation over Rh Catalyst Thin Films Sputtered on YSZ and TiO2 / YSZ Supports

The effect of electrochemical promotion of catalysis or nonfaradaic electrochemical modification of catalytic activity or electropromotion was investigated for the model reaction of ethylene oxidation on sputter-coated Rh films. The thin (40 nm) Rh films were deposited on -stabilized- (YSZ) and on YSZ coated with a thin porous layer. It was found that the catalytic activity of Rh for oxidation can be reversibly enhanced via anodic current or potential application by up to a factor of 80 and that the increase in the oxidation rate is up to 2000 times larger than the rate of supply of to the Rh catalyst-electrode. Smaller anodic currents cause periodic catalytic rate and potential oscillations. The layer was found to enhance the open-circuit catalytic activity and to stabilize the electrochemically promoted catalyst state. The observed pronounced electrochemical promotion behavior is due to the anodically controlled migration (back spillover) of species from YSZ to the Rh/gas interface and the concomitant destabilization, via repulsive lateral interactions, of the formation of surface The electropromotion of such thin metal catalyst films with metal dispersion near 10% is of significant importance for the practical utilization of the electrochemical promotion of catalysis. © 2004 The Electrochemical Society. All rights reserved.

Well-Defined Highly Active Heterogeneous Catalyst System for the Coupling Reactions of Carbon Dioxide and Epoxides

The poly(4-vinylpyridine)-supported zinc halide catalysts, prepared from a reaction of ZnX2 and poly(4-vinylpyridine), exhibit high selectivity and activity for the coupling reaction of CO2 and ethylene oxide or propylene oxide. Solid NMR characterization of the poly(4-vinylpyridine)-supported ZnBr2 catalyst and its reaction product with propylene oxide and/or CO2 show that a pyridinium-alkoxy ion-bridged zinc bromide complex is functioning as an active species, such as in the homogeneous catalysis with L2ZnBr2 (L = pyridine or methyl-substituted pyridine).

Formation of a stable surface oxametallacycle that produces ethylene oxide.

Temperature programmed desorption, high-resolution electron energy loss spectroscopy (HREELS), and density functional theory (DFT) were used to investigate the adsorption and reaction of ethylene oxide (EO) on the Ag(111) surface. When EO is dosed onto Ag(111) at 140 K it adsorbs molecularly, desorbing without reaction at approximately 200 K. On the other hand, when EO is dosed at 250 K, the ring-opening of EO is activated, and a stable surface intermediate is formed. This intermediate reacts at 300 K to re-form EO plus a few other products. HREELS and DFT studies suggest that this stable intermediate is a surface oxametallacycle. Moreover, the activation energies observed for the reaction of the oxametallacycle to form EO are in an excellent agreement with the values reported for the steady-state ethylene epoxidation process. This work represents the first demonstration of surface oxametallacycle ring-closure to form EO. Comparison of the spectroscopic results obtained from silver single crystals and supported catalysts strongly suggests that oxametallacycles are important intermediates in silver-catalyzed ethylene epoxidation.

Kinetics of the reactions of ethylene oxide with water and ethylene glycols

AbstractThis study of the water‐contamination reactions of ethylene oxide was conducted by Arthur D. Little, Inc. with funding from, and under the auspices of, the Ethylene Oxide Industry Council, part of the American Chemistry Council. Significant experimental and technical contributions were also made by staff from Shell Chemicals' Westhollow Technology Center in Houston, Texas, and Union Carbide Corporation's Research Center in South Charleston, West Virginia. Unique fourth‐order kinetics for the reactions of ethylene oxide with water, and ethylene oxide with ethylene glycols were derived and validated, as were kinetics for the reactions of neat ethylene oxide and the decomposition of ethylene glycols. The latter data was incorporated into a reaction model useful for the determination of ethylene oxide storage stability and pressure relief system design under water‐contamination scenarios.

Synthesis of dimethyl carbonate and glycols from carbon dioxide, epoxides, and methanol using heterogeneous basic metal oxide catalysts with high activity and selectivity

This paper gives a comprehensive report on a two-step synthesis of dimethyl carbonate (DMC) from epoxides, carbon dioxide and methanol using various basic metal oxide catalysts. The first step is the reaction of ethylene oxide or propylene oxide with CO 2 to form the corresponding cyclic carbonates, and the second step is the transesterification reaction of the cyclic carbonates with methanol to DMC and glycols. Among the catalysts examined, MgO is the most active and selective for both these reactions. Other alcohols can be used for the second step, but the activity decreases as the carbon number of the alcohol increases. Although a one-pot synthesis of DMC, i.e. the sequential reaction of the epoxide, CO 2 and methanol, is also possible with MgO, the selectivity is low because of the alcoholysis of the epoxide. In contrast with the reactions of ethylene oxide and propylene oxide, when styrene oxide is used for the first reaction and for the one-pot synthesis, mandelic acid is produced. Basic properties of the metal oxide catalysts were measured by temperature programmed desorption of CO 2. The relationship between the catalytic performance and the basic property is discussed.

Cycloaddition of CO2 to Epoxides over Solid Base Catalysts

The cycloaddition of carbon dioxide to various epoxides (ethylene oxide, epoxybutene, and epoxypropylbenzene) over solid base cata-lysts (KX zeolite, Cs-loaded KX zeolite, Cs-doped alumina, and MgO) was performed in a batch autoclave reactor at 423 K and with excess CO2. Catalysts were characterized by elemental analysis, N2 physisorption, and CO2 adsorption microcalorimetry. The combination of results from elemental analysis and microcalorimetry showed that the occluded base sites on the Cs/KX were actually composed of occluded Cs and K species that could be removed by washing with water. The activity of the zeolite catalysts for ethylene oxide conversion to ethylene carbonate depended on the basicity of the sample, with the sample containing occluded alkali metal oxides being the most active. In addition, the site-time yields of ethylene carbonate formation, based on CO2 adsorption capacity, over Cs/KX, Cs/Al2O3, and MgO were similar to each other and were within a factor of 4 of the site-time yield seen with the homogeneous catalyst [N(C2H5)4]Br. The rates of epoxypropylbenzene conversion over the solid base catalysts were much lower than the rates of ethylene oxide conversion, presumably due to steric hindrance of the bulky side group on the former. Rate measurements with a mixture of ethylene oxide and epoxypropylbenzene over Cs/KX and MgO indicated that most of the basic sites on Cs/KX are located in the zeolite micropores. A high catalytic activity of Cs/Al2O3 for all of the epoxides studied suggests that proximity of surface Lewis acid sites to surface base sites is needed for the cycloaddition reaction. In the case of a zeolite catalyst, addition of a small amount of water enhanced the rate ethylene oxide reaction without significant formation of glycol side products.

Structure/function relationships for basic zeolite catalysts containing occluded alkali species

The basicity and reactivity of alkali-modified zeolites were investigated in order to elucidate the role of occluded species on catalytic activity. To synthesize intrazeolite oxide or metal species, cesium acetate or cesium azide was impregnated into the pores of zeolites and decomposed in situ. To characterize the basicity of the samples, we used adsorption of iodine and carbon dioxide. The blue shift in the UV–visible spectrum of adsorbed iodine was found to increase with increasing electropositivity of the exchangeable cation, indicating greater donor strength of the zeolite framework. Cesium-exchanged zeolite X was an active catalyst for the reaction of ethylene oxide and carbon dioxide to form ethylene carbonate. For a series of faujasite-type zeolites with different loadings of occluded cesium oxide, the CO 2 uptake increased linearly with the amount of occluded Cs. The catalytic activities of the CsO x /CsX samples for the isomerization of 1-butene and dehydrogenation of 2-propanol increased linearly with the amount of excess cesium, consistent with results from the adsorption of CO 2. A majority of the base sites on these materials exhibited a heat of CO 2 adsorption around 85 kJ mol −1, which is much lower than the 270 kJ mol −1 seen on bulk cesium oxide. After thermal pretreatment, Na(azide) and Cs(azide) modified X zeolites catalyzed the side-chain alkylation of toluene with ethylene and the side-chain alkenylation of o-xylene with butadiene, whereas occluded cesium oxide was inactive in the reactions.

Tetrahydrofuran polymerization initiated by heteropolyacid in the presence of ethylene oxide: Reaction behavior of water and glycol

The reaction behavior of water and low molecular weight glycol in tetrahydrofuran polymerization initiated by H3PW12O40 in the presence of ethylene oxide has been studied. A lot of water was used in the hydrolysis reaction of ethylene oxide at the early stage of the polymerization and transformed into ethylene glycol (EG), which was consumed subsequently through a chain transfer reaction. EG was more reactive both than 1,4-butylene glycol and hexamethylene glycol toward propagating species, and the reaction rate constants at 0°C were determined by GC to be 0.142, 8.83 × 10−2, and 5.53 × 10−2 L · mol−1s−1, respectively. The molecular weight of the product can be predicted by an equation based upon conversion of polymerization and the concentrations of molecular weight controller and H3PW12O40. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1821–1826, 1999

IR study of the secondary reaction of ethylene oxide over silver catalyst supported on mesoporous material

The secondary reaction of ethylene oxide over silver catalyst supported on MCM-41 mesoporous material was investigated by thein-situ IR method. MCM-41 mesoporous material with a large content of hydroxyl group was very active in catalyzing the isomerization of ethylene oxide to acetaldehyde. The reduction of hydroxyl group by silane treatment or silver loading suppressed the isomerization of ethylene oxide. The selectivity for ethylene oxide in the partial oxidation of ethylene is enhanced by silane modification, revealing the acceleration of the consumption of ethylene oxide on the hydroxyl group.

Copper(II) complexes of tetraaza macrocycles bearing pendant arms: syntheses, structures and properties

A new difunctionalized tetraaza macrocycle, 1,8-bis(2-hydroxyethyl)-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane, H2L2 has been synthesized in one step by the reaction of ethylene oxide and C-rac-5,5,7,12,12, 14-hexamethyl-1,4,8,11-tetraazacyclotetradecane (L1). The crystal structure of [Cu(H2L2)][ClO4]2 1 shows the metal ion in tetragonally elongated octahedral geometry, co-ordinated by the oxygen atoms of the pendant arms in the trans-axial position. Copper(II) complexes were also synthesized and characterized from other 1,8-disubstituted macrocyclic ligands L3, L4, HL5, H2L6, L8 and H2L9. The molecular structure of [CuL3][ClO4]2 2 (R1 = R2 = CH2CH2CN) and [CuL5]ClO4, 4 (R1 = H, R2 = CH2CO2–) shows the macrocycle in trans-I configuration with square planar and distorted square pyramidal geometries respectively at the metal centers. The structures of complexes [CuL8][ClO4]2 6 [L8 = 1,8-bis(2-cyanoethyl)-4,7,11,14-tetramethyl-1,4,8,11-tetraazacyclotetradecane] and [Cu(H2L9)][ClO4]2 7 (corresponding CH2CO2H derivative) show the macrocyclic ligand in the trans-III configuration. Interestingly the two pendant acetic acid groups of H2L9 in 7 remain protonated and co-ordinate through the carbonyl oxygen atoms in trans-octahedral geometry. The cyclic voltammetric studies of the complexes revealed that the copper(I) oxidation state is highly stabilized by the ligands L3 and L8. The pH dependent co-ordination geometry changes of complexes 4, [CuL6] 5 (R1 = R2 = CH2CO2–) and 7 based on the changes in their electronic spectra are discussed. The kinetics of acid promoted dissociation reactions of complexes 2 and 6 has been studied in HCl–NaCl solutions (I = 5.0 M). The possible mechanisms of the reactions, the factors influencing the rate and the relative importance of the solvent separation and protonation pathways are discussed.

Specific phenomena during the copolymerization of trioxane and ethylene oxide

AbstractWe, at Asahi Chemical in Japan, have industrialized three types of polyacetal resins, that is, the acetal homopolymer, copolymer and block copolymer using anionic, cationic and anionic polymerization techniques, respectively. During this industrialization, we observed various phenomena, which were not previously reported. First, the authors outline the three technologies for producing each type of polyoxymethylene from an industrial viewpoint. Next, the authors discuss a newly found reaction during the induction period of the trioxane and ethylene oxide copolymerization. Experimental proof of direct ring expansion between the reaction of trioxane and ethylene oxide is discussed and various novel cyclic compounds are also shown. To the best of our knowledge, this reaction may be the world's first experimental proof of direct ring expansion of the reaction of a cyclic monomer. Third, the authors also discuss the newly founded morphospecific polymer from the copolymerization of trioxane and ethylene oxide using boron trifluoride dibutyl ether as an initiator.

Oxidation of Alkenes, Sulfides, Amines, and Phosphines with Peroxynitrous Acid: Comparison with Other Oxidants Such as Peroxyformic Acid and Dimethyldioxirane

The oxidation reactions of ethylene, propene, dimethyl sulfide, trimethylamine, and trimethylphosphine with peroxynitrous acid have been studied computationally with the B3LYP, MP2, MP4, CISD, QCISD, and QCISD(T) levels of theory. The activation barriers for the alkene (ethylene and propene) epoxidations (18.4 and 15.5 kcal/mol at the QCISD(T)/6-31G*//QCISD/6-31G* level, respectively) and for the oxidations of dimethyl sulfide, trimethylamine, and trimethylphosphine (8.3, 4.6, and 0.5 kcal/mol at the QCISD(T)/6-31G*//B3LYP/6-311G** level, respectively) with peroxynitrous acid are similar to the barriers of their oxidations with peroxyformic acid and dimethyldioxirane, although these peroxides have very diverse O−O bond dissociation energies. Therefore, the feasibility of alkene epoxidation and the oxidations of methyl-substituted sulfides, amines, and phosphines by peroxynitrous acid should not differ significantly from those for peroxyformic acid and dimethyldioxirane. The transition structures for the e...

Analysis of the Reaction in the Early Stage of the Copolymerization of Trioxane and Ethylene Oxide. 2-Formation of 1,3,5,7,10-Pentaoxacyclododecane.

In a previous report, we noted a new direct reaction between 1 mole of trioxane and 1 mole of ethylene oxide and the formation of a novel cyclic formal of 1, 3, 5, 7-tetraoxacyclononane. We have now determined a new reaction and novel cyclic compound from the reaction of trioxane and ethylene oxide. The novel cyclic compound was separated and collected using a micro-distillation apparatus and gas chromatographic method. Its chemical structure was confirmed using 1H-NMR, 13C-NMR, mass spectrum and elemental analysis. The new isolated novel cyclic compound was 1, 3, 5, 7, 10-pentaoxacyclododecane, which might be formed by the direct reaction of 1 mole of trioxane and 2 moles of ethylene oxide. In the commercial base acetal copolymer, which was produced by the copolymerization of trioxane and ethylene oxide, it is known that there is a consecutive two units sequence of ethylene oxide, and this consecutive 2 ethylene oxide unit sequence might be postulated to come from the ring opening-polymerization of the novel cyclic formal of 1, 3, 5, 7, 10-pentaoxacyclododecane.