Reaction rate of carbon dioxide in glycidyl methacrylate solution using tricaprylylmethylammonium chloride as a catalyst

Carbon dioxide was absorbed into organic solutions of glycidyl methacrylate (GMA) in a semi-batch stirred tank with a plane gas-liquid interface at 101.3 kPa to measure absorption rates of carbon dioxide, from which the reaction kinetics between carbon dioxide and GMA were studied by using tricaprylylmethylammonium chloride catalyst. The reaction rate constants of the reaction were estimated by using the mass transfer mechanism accompanied by the pseudo-first-order reaction. An empirical correlation formula between the reaction rate constants and the solubility parameters of solvents such as toluene,N-methyl-2-pirrolidinone, and dimethyl sulfoxide was presented.     

Kinetic parameters using an immobilized tetrahexylammonium chloride catalyst in glycidyl methacrylate reaction with carbon dioxide

A soluble copolymer-supported catalyst containing pendant tetrahexylammonium chloride was synthesized by the radical copolymerization of p-chloromethylated styrene with styrene followed by the addition reaction of the resulting copolymer with trihexylamine. Initial absorption rate of carbon dioxide into glycidyl methacrylate (GMA) solutions containing the catalyst was measured in a semi-batch stirred tank with a plane gas-liquid interface at 101.3 kPa. The reaction rate constants of the elementary reaction between carbon dioxide and GMA were evaluated from analysis of the mass transfer mechanism accompanied by the elementary reactions based on film theory. Solvents such as toluene, N-methyl-2-pirrolidinone, and dimethyl sulfoxide influenced the reaction rate constants. Furthermore, this catalyst was compared to monomeric tetrahexylammonium chloride under the same reaction conditions.     

Reaction kinetics between carbon dioxide and glycidyl methacrylate using trihexylamine immobilized ionic liquid on MCM41 catalyst

An ionic liquid (THA-CP-MS41), trihexylamine-immobilized on chloropropyl-functionalized MCM41, was synthesized by a grafting technique through a co-condensation method and used as a catalyst in the reaction of carbon dioxide with glycidyl methacrylate (GMA). CO₂ was absorbed into the heterogeneous system of the GMA solution and dispersed with solid particles of the catalyst in a batch stirred tank with a plane gas–liquid interface at 101.3 kPa. The absorption of CO₂ was analyzed using the mass transfer mechanism accompanied by chemical reactions based on the film theory. The proposed model fits the measured data of the enhancement factor to obtain the reaction rate constants.Solvents such as N,N-dimethylacetamide, N-methyl-2-pyrrolidinone, and dimethyl sulfoxide influenced reaction rate constants.     

Reaction kinetic for poly(styrene-co-vinylbenzyl chloride)-supported catalyst containing pendant tetraethylammonium chloride in the reaction of glycidyl methacrylate with carbon dioxide

A soluble copolymer-supported catalyst containing pendant triethylammonium chloride was synthesized by the radical copolymerization of p-chloromethylated styrene with styrene followed by the addition reaction of the resulting copolymer with triethylamine. Initial absorption rate of carbon dioxide into glycidyl methacrylate (GMA) solutions containing the catalyst was measured in a semi-batch stirred tank with a plane gas–liquid interface at 101.3 kPa. The reaction rate constants of the reaction between carbon dioxide and GMA were evaluated from analysis of the mass transfer mechanism accompanied by the elementary reactions based on the film theory. Solvents such as toluene, N-methyl-2-pirrolidinone, and dimethyl sulfoxide influenced on the reaction rate constants. Furthermore, this catalyst was compared to the monomeric tetraethylammonium chloride under the same reaction conditions.     

Copolymerization of phenyl glycidyl ether with carbon dioxide catalyzed by ionic liquids

The copolymerization of phenyl glycidyl ether (PGE) and carbon dioxide was performed without any solvent in the presence of ionic liquid as catalyst. The reaction was carried out in a batch autoclave reactor. The carbonate content of polycarbonate was affected by the structure of imidazolium salt ionic liquid; the one with the cation of bulkier alkyl chain length and with more nucleophilic anion showed better reactivity. However, the yield of carbon dioxide addition decreased when hexyl or octyl containing ionic liquids were used in place of butyl group in 1-alkyl-3-methyl imidazolium salts. The carbonate content and turnover number (TON) of the polycarbonate increased as the reaction temperature increased from 40 to 80 ‡C. However, the carbonate content decreased with increasing reaction time.     

Catalytic performance of pyridinium salt ionic liquid in the synthesis of cyclic carbonate from carbon dioxide and butyl glycidyl ether

The catalytic performance of pyridinium salt ionic liquids in the reaction of butyl glycidyl ether and carbon dioxide was investigated in this study. The catalytic activity was studied in a batch reactor with different 1-alkylpyridinium salt ionic liquids at 60–140°C. The conversion of butyl glycidyl ether was affected by the structure of the ionic liquid; the one with the cation of bulkier alkyl chain length showed better reactivity. The effect of carbon dioxide pressure, reaction temperature and zinc bromide co-catalyst on this reaction was also discussed.     

Absorption of carbon dioxide into aqueous colloidal silica solution with different sizes of silica particles containing monoethanolamine

Carbon dioxide was absorbed into an aqueous nanometer-sized colloidal silica solution in a flat-stirred vessel at 25 °C and 101.3 kPa to measure the absorption rate of CO₂. The concentrations of silica were in the range of 0–31 wt% and the sizes were 7, 60, and 111 nm. The solution contained monoethanolamine (MEA) of 0–2.0 kmol/m³. The volumetric liquid-side mass transfer coefficient (k _L a) of CO₂ was correlated with the empirical formula representing the rheological property of silica solution. The use of the aqueous colloidal silica solution resulted in a reduction of the absorption rate of CO₂ compared with Newtonian liquid based on the same viscosity of the solution. The chemical absorption rate of CO₂ was estimated by film theory using k _L a and physicochemical properties of CO₂ and MEA.     

Absorption of carbon dioxide into aqueous PAA solution containing diethanolamine

Carbon dioxide was absorbed into aqueous polyacrylamide (PAA) solution containing diethanolamine (DEA) of 0–2 kmol/m³ in a flat-stirred vessel with the impeller of 0.034 m and agitation speed of 50 rpm at 25 °C and 0.101 MPa to measure the absorption rate of CO₂. The volumetric liquid-side mass transfer coefficient (k_La) was obtained from the dimensionless empirical correlation formula presenting the rheological behavior of aqueous PAA solution. PAA with elastic property of non-Newtonian liquid made the rate of chemical absorption of CO₂ accelerate compared with Newtonian liquid based on the same viscosity of the solution. The estimated value of the absorption rate of CO₂ was obtained from the model based on the film theory accompanied by chemical reaction and compared with the measured value.     

Effect of cocatalyst and carbon dioxide pressure on the synthesis of polycarbonate from phenyl glycidyl ether and carbon dioxide

The copolymerization of phenyl glycidyl ether (PGE) and carbon dioxide was performed in the presence of ionic liquid catalyst. 1-Butyl-3-methyl imidazolium chloride, tetrabutylamouim chloride and 1-n-butylpyridinium chloride were used as catalyst for this reaction carried out in a batch reactor. All the ionic liquid catalysts showed good catalytic activity for the synthesis of polycarbonates with very low polydispersity, close to 1. The carbonate content, turnover number (TON), and average molecular weight of the copolymer were affected by the structure of the ionic liquid. High carbon dioxide pressure enhanced TON and carbonate content because of the increase of carbon dioxide absorption in PGE solution. ZnBr₂ and a Zn-Co cyanide complex were also tested as a catalyst and/or cocatalyst for this reaction to compare their catalytic performance with the imidazolium salt ionic liquids.     

Comparative studies on the performance of immobilized quaternary ammonium salt catalysts for the addition of carbon dioxide to glycidyl methacrylate

The addition of carbon dioxide to glycidyl methacrylate (GMA) was investigated in a semi-batch reactor using immobilized quaternary ammonium chloride catalysts. Five different catalysts were prepared with the following supports: (1) soluble poly(ST-co-VBC)[C1], (2) insoluble poly(ST-DVB-VBC)[C2], (3) macroporous poly(ST-DVB-VBC)[C3], (4) poly(ST-co-VBC)-MMT[C4], (5) modified MCM-41[C5]. The addition of carbon dioxide to GMA can be considered as pseudo first-order with the concentration of GMA. The soluble poly(ST-co-VBC)-supported catalyst containing benzyltributylammonium chloride group showed the highest reaction rate. The order of the pseudo first-order rate constant for the catalysts was C1 > C3 > C2 > C4 > C5. The activation energy for the C1–C5 catalysts was 11.5, 28.1, 20.8, 36.6 and 39.3 kJ/mol, respectively. The immobilized catalysts can be reused for at least four successive runs without any considerable loss of their initial reactivities.     

Absorption of carbon dioxide into non-aqueous solutions ofN-methyldiethanolamine

The chemical absorption rate of carbon dioxide was measured in non-aqueous solvents, which dissolved N-methyldiethanoamine (MDEA), such as methanol, ethanol, n-propanol, n-butanol, ethylene glycol, propylene glycol, and propylene carbonate, and water at 298 K and 101.3 kPa using a semi-batch stirred tank with a plane gas-liquid interface. The overall reaction rate constant obtained from the measured rate of absorption of carbon dioxide under the condition of fast pseudo-first-order reaction regime was used to get the apparent reaction rate constant, which yields the second-order reaction rate constant and the reaction order of the overall reaction. There was approximately linear dependence of the logarithm of the rate constant for the overall second-order reaction on the solubility parameter of the solvent. In non-aqueous solutions of (MDEA), dissolved carbon dioxide is expected to react with solvated (MDEA) to produce an ion pair.     

Chemical absorption of carbon dioxide into phenyl glycidyl ether solution containing THA-CP-MS41 catalyst

Carbon dioxide was absorbed into the phenyl glycidyl ether (PGE) solution within a range of 0–2.0 kmol/m³ in a stirred batch tank with a planar gas-liquid interface at 333–363 K and 101.3 kPa. Trihexylamine-immobilized on chloropropyl-functionalized MCM-41 (THA-CP-MS41) was used as a mesoporous catalyst, dispersed in organic liquid for the reaction between carbon dioxide and PGE. The measured absorption rates were analyzed to obtain the reaction kinetics of the consecutive chemical reactions which consisted of two steps using the mass transfer mechanism based on film theory. The overall reaction kinetics, analyzed with the pseudo-first-order reaction constant in the consecutive reaction model, was equivalent to the consecutive reaction kinetics. Effects of polar solvent, such as N, N-dimethylacetamide, N-methyl-2-pyrrolidinone, and dimethyl sulfoxide, on the reaction rate constants were observed using the solubility parameter of the solvent.     

Cycloaddition of carbon dioxide to epichlorohydrin using ionic liquid as a catalyst

The cycloaddition of carbon dioxide to epichlorohydrin was performed without any solvent in the presence of ionic liquid as catalyst. 1-Alkyl-3-methyl imidazolium salts of different alkyl group (C₂, C₄, C₆, C₈) and anions (Cl⁻, BF₄⁻, Br⁻, PF₆⁻) were used for this reaction carried out in a batch autoclave reactor. The conversion of epichlorohydrin was affected by the structure of the imidazolium salt ionic liquid; the one with the cation of longer alkyl chain length and with more nucleophilic anion showed better reactivity. The conversion of epichlorohydrin increased as the temperature increased from 60°C to 140°C. It also increased with increasing carbon dioxide pressure probably due to the increase of the absorption of carbon dioxide into the mixture of epichlorohydrin and the ionic liquid. Zinc bromide was also tested for its use as a cocatalyst in this reaction. This work was presented at the 6 ^th Korea-China Workshop on Clean Energy Technology held at Busan, Korea, July 4–7, 2006.     

MCM-41分子筛加氢裂化催化剂的研究

按水热法合成出介孔MCM-41分子筛，在不同的气氛下焙烧脱除有机模板剂。在固定床流动反应器上，与USY分子筛对比了正庚烷加氢裂化结果，发现MCM-41分子筛有较好的抗氮中毒能力，且其稳定时的加氢裂解活性比USY分子筛高。     

Absorption of carbon dioxide into glycidyl methacrylate solution with quaternary onium salts

Carbon dioxide was absorbed into organic solutions of glycidyl methacrylate (GMA) in a semi-batch stirred tank with a plane gas-liquid interface at 101.3 kPa to measure absorption rates of carbon dioxide, from which the reaction kinetics between carbon dioxide and GMA with quaternary onium salts as catalysts was obtained. The reaction rate constants were estimated by the mass transfer mechanism accompanied by the pseudo-first-order reaction method. An empirical correlation formula between the reaction rate constants and the solubility parameters of solvents such as toluene, N-methyl-2-pirrolidinone, and dimethyl sulfoxide was presented.     

Absorption of carbon dioxide into aqueous colloidal silica solution with diisopropanolamine

Carbon dioxide was absorbed into the aqueous nanometer-sized colloidal silica solution of 0–31 wt% and diisopropanolamine of 0–2 kmol/m³ in a flat-stirred vessel with the impeller of various sizes and speeds at 25 °C and 0.101 MPa to measure the absorption rate of CO₂. The volumetric liquid-side mass transfer coefficient (k_La) of CO₂ was used to obtain the empirical correlation formula containing the rheological behavior of the aqueous colloidal silica solution. Reduction of the measured k_La was explained by the viscoelastic properties of the aqueous colloidal silica solution. The theoretical value of the absorption rate of CO₂ was estimated from the model based on the film theory accompanied by chemical reaction and compared with the measured value.     

Chemical absorption of carbon dioxide into oxirane solution containing ID-CP-MS41 catalyst

CP-MS41 was synthesized by hydrolysis of tetraorthosilicate, as a silicon source, with 3-chloropropyltriethoxysilane as an organosilane using cetyltrimethylammonium bromide as a template. ID-CP-MS41 was synthesized by immobilization of imidazole on the CP-MS41 and was dispersed in organic liquid as a mesoporous catalyst for the reaction between carbon dioxide and oxirane. Phenyl glycidyl ether and glycidyl methacrylate were used as oxiranes. Carbon dioxide was absorbed into the oxirane solution in a stirred batch tank with a planar gas-liquid interface within a range of 0–2.0 kmol/m³ of oxirane and 333–363 K at 101.3 kPa. The measured values of absorption rate were analyzed to obtain the reaction kinetics using the mass transfer mechanism associated with the chemical reactions based on the film theory. The overall reaction of CO₂ with oxirane, which is assumed to consist of two steps-i) a reversible reaction between oxirane (B) and catalyst of ID-CP-MS41 (QX) to form an intermediate complex (C₁), and ii) irreversible reaction between C₁ and CO₂ to form QX and five-membered cyclic carbonate (C)-was used to obtain the reaction kinetics through the pseudo-first-order reaction model. Polar solvents such as N, N-dimethylacetamide, Nmethyl-2-pyrrolidinone, and dimethyl sulfoxide affected the reaction rate constants.     

Synthesis of cyclic carbonate from allyl glycidyl ether and CO2 over silica-supported ionic liquid catalysts prepared by sol-gel method

A silica-supported ionic liquid (Im-IL) was proven to be an effective heterogeneous catalyst for solventless synthesis of cyclic carbonate from allyl glycidyl ether (AGE) and carbon dioxide. Im-IL catalysts were prepared by sol-gel method. The synthesis of cyclic carbonate from AGE and CO₂ was carried out in a batch autoclave reactor. Im-IL with shorter alkyl chain length showed the highest conversion of AGE, probably due to the steric hindrance for the formation of intermediate from the catalyst prepared by using longer alkyl chains and AGE. High temperature and high pressure were favorable for the conversion of AGE. Im-IL can be reused for the reaction up to two consecutive runs without any considerable loss of its catalytic activity.     

The formation mechanisms of multi-wall carbon nanotubes over the Ni modified MCM-41 catalysts

Multi-wall carbon nanotubes (MWCNTs) were grown by thermal chemical vapor deposition (thermal CVD) of CH₄ by using Ni-MCM-41 as the catalyst. Methane pyrolysis has been performed in a quartz tube reactor over the catalyst surface to form carbon atoms via dehydrogenation process. The migration and rearrangement of the surface carbon atoms result in the formation of MWCNTs. Transmission electron microscope (TEM) and scanning electron microscope (SEM) were used to determine the morphologies and structures of CNTs, and Raman spectroscopy was exploited to analyze their purity with the relative intensity between the D-band (Disorder band) in the vicinity of 1,350 cm⁻¹ which is characteristic of the sp³ structure and G-band (Graphitic band) in vicinity of 1,580 cm⁻¹ which is characteristic of the sp² structure. In addition, the controlling factors of methane pyrolysis such as the catalyst composition; the reaction temperature, and the methane flow rate on the formation of MWCNTs were investigated to optimize the structure and yield of MWCNTs. SEM/TEM results indicate that the yield of the CNTs increases with increasing Ni concentration in the catalyst. The optimized reaction temperature to grow CNT is located between 640 and 670 °C. The uniform and narrow diameter MWCNTs form at lower flow rate of methane (∼30 sccm), and non-uniform in diameter and disorder structure of MWCNTs are observed at higher flow rate of methane. This is consistent with Raman analysis that the relative intensity of I _D/I _G increases with increasing methane flow rate. The formation mechanisms of the MWCNTs on the Ni-MCM-41 catalyst have been determined to be a Tip-Growth mode with a nanoscale catalyst particle capsulated in the tip of the CNT.     

环己烷催化氧化制环己酮的MCM-41催化剂研究

以十六烷基三甲基溴化铵为模板剂,正硅酸乙酯为硅源,采用水热合成法制备纯MCM-41分子筛和掺杂不同金属离子的MCM-41分子筛,并采用等体积浸渍法将一定量的金属离子负载在纯MCM-41分子筛内表面上,制备了负载型和掺杂型2类不同的MCM-41分子筛催化剂.分别考察了负载和掺杂的金属种类、金属Cr负载和掺杂量等对环己烷氧化制环己酮中的催化活性和选择性的影响.研究表明:采用掺杂制备的MCM-41分子筛催化剂活性明显高于负载型MCM-41分子筛催化剂;Cr掺杂量增加,虽然环己烷氧化转化率增加,但产物选择性下降;掺杂Cr的MCM-41分子筛催化剂,用于环己烷氧化制环己酮,在Si与Cr摩尔比为50以下、反应温度75℃、H2O2与环己烷摩尔比为1.2的条件下,环己烷的转化率可达60%左右,环己酮和环己醇的总选择性可达94%以上.